Hepcidin in human iron disorders: diagnostic implications.
Physiol Res
2006;55:667-74.
(182.) Tussing-Humphreys LM, Nemeth E, Fantuzzi G, Freels S,
Holterman AX, Galvani C, et al. Hereditary
hemochromatosis: genetic complexity and new diagnostic approaches. AAPS J 2010;12:646-57.
(23.) Merle U, Fein E, Gehrke SG, Stremmel W, Kulaksiz H. Hepcidin-25 induces the internalization and degradation of ferroportin (35-38), resulting in increased
intracellular iron stores, decreased dietary iron absorption, and
decreased circulating iron concentrations (Fig. Kidney Int 2009; 75:976-81.
(187.) Lapenna D, Pierdomenico SD, Ciofani G, Ucchino S, Neri M,
Giamberardino MA, Cuccurullo F. 4). pylori-induced
inflammation does not influence iron status through increased hepcidin
production in childhood (118).
(34.) Wan L, Bellomo R, Di GD, Ronco C. PLoS ONE 2009;4:e6618.
(157.) Cercamondi CI, Egli IM, Ahouandjinou E, Dossa R, Zeder C,
Salami L, et al. J Clin Invest 2009;119:1159-66.
Honoraria: None declared.
The development and validation of hepcidin assays paved the way for
a large number of human studies that considerably increased our
understanding of the physiology and pathophysiology of iron homeostasis
and moreover demonstrated promising applications for hepcidin in
diagnostic medicine (Table 2).
(48.) Finberg KE, Whittlesey RL, Fleming MD, Andrews NC.
Down-regulation of Bmp/Smad signaling by Tmprss6 is required for
maintenance of systemic iron homeostasis. Blood 2009;113: 6225-36.
In a proof-of-principle study, Sasu et al. Serum hepcidin levels are innately low in
HFE-related haemochromatosis but differ between C282Y-homozygotes with
elevated and normal ferritin levels. Clinical stability, time of sampling in relation to iron and ESA
therapy, and iron and EPO dosage and dialysis regimens differ between
studies and are likely to influence results. Serum prohepcidin concentration: no association with iron
absorption in healthy men; and no relationship with iron status in men
carrying HFE mutations, hereditary haemochromatosis patients undergoing
phlebotomy treatment, or pregnant women. Hepcidin, a new iron regulatory peptide. Nat Genet 2006;38:531-9.
Expert Testimony: None declared.
(221.) Klaus S, Langsetmo I, Spong S, Gervasi B, Nichols B, Fourney
P, et al. Blood Cells Mol Dis 2008;40: 347-52.
Consultant or Advisory Role: D.W. Br J Haematol
2009;145:657-64.
(107.) Kroot JJ, Hendriks JC, Laarakkers CM, Klaver SM, Kemna EH,
Tjalsma H, Swinkels DW. A new mouse liverspecific gene, encoding a protein
homologous to human antimicrobial peptide hepcidin, is over-expressed
during iron overload. This effect might be attributable in part to
the effect of hypoxia on EPO expression and thus erythropoietic
activityand/or possibly via a direct interaction with hepatocyte
receptors (51). J Hepatol
2009;50:1219-25.
Administration of erythropoiesis-stimulating agents (ESA) was found
to decrease (hepatocyte) hepcidin production in murine, human, and in
vitro studies (50-53). Patients with cancer often suffer from anemia,
generally in association with other markers of inflammation. Haematologica 2007;92: 857-8.
(186.) Kraml PJ, Klein RL, Huang Y, Nareika A, Lopes-Virella MF.
Iron loading increases cholesterol accumulation and macrophage scavenger
recep tor I expression in THP-1 mononuclear phagocytes. First, any postexercise free iron uptake by the RE
macrophages may be trapped within the scavenger cell owing to the action
of hepcidin on the ferroportin transporters, thereby affecting the
recycling of iron back into the circulation. Although no specific hepcidin
therapies are available, several compounds are under development as
hepcidin agonists or antagonists [reviewed in (204-206)]. Am J
Trop Med Hyg 2007;77:623-6.
The quantification of hepcidin has been found to be complicated by
its tendency to aggregate (79) and to stick to laboratory plastics,
necessitating implementation of robust laboratory procedures.
Furthermore, progress in developing a conventional immunochemical hepcidin assay has been hampered by difficulties in generating specific
antihepcidin antibodies in hosts such as rabbits. However, circadian variation in hepcidin could
be secondary as well, because it might be driven by the influence of
iron intake during the day. The hepatocellular interaction of IL-6
with its receptor activates the janus kinase/signal transducer and
activator of transcription-3 signaling pathway (59,64-66). Blood
2010;115:3616-24.
(153.) de Mast Q, Nadjm B, Reyburn H, Kemna EH, Amos B, Laarakkers
CM, et al. Biochim Biophys Acta 2009;1790:718-23.
(61.) Silvestri L, Pagani A, Camaschella C. Serum hepcidin concentration in chronic
haemodialysis patients: associations and effects of dialysis, iron and
erythropoietin therapy. Blood Cells Mol Dis 2010;45: 238-45.
(170.) van der Putten K, Jie KE, van den Broek D, Kraaijenhagen RJ,
Laarakkers C, Swinkels DW, et al. Blocking HIF
could also be of useful for increasing hepcidin concentrations in
iron-overload diseases.
(97.) Grebenchtchikov N, Geurts-Moespot AJ, Kroot JJ, den Heijer M,
Tjalsma H, Swinkels DW, Sweep FG. Tjalsma, Radboud University Ni jmegen
Medical Centre (among others offers services through
hepcidinanalysis.com); D.W. However, the use of
different assay technologies to assess hepcidin concentrations in
patients with disorders of iron metabolism makes it difficult to
interpret the results of the many reported studies. Mass spectrometry-based proteomic analysis of urine in acute kidney
injury following cardiopulmonary bypass: a nested case-control study. (89)
MALDI-TOF MS Kroot et al. Hepcidin regulates cellular iron efflux by binding to
ferroportin and inducing its internalization. Swinkels, Radboud University Nijmegen Medical Centre (among others offers services through
hepcidinanalysis.com).
(203.) Peeling P. 2) (12-17). Clin Chem 2010;56:1725-32.
Hepcidin Methods
(160.) Weiss G, Goodnough LT. Regulation of hepcidin and iron-overload
disease. Erythroid activity, transfusion iron overload, and
hepcidin levels in patients with myelodysplastic syndrome. An insight into the relationships between
hepcidin, anemia, infections and inflammatory cytokines in pediatric
refugees: a cross-sectional study. vivax
malaria. The iron
regulatory peptide hepcidin is expressed in the heart and regulated by
hypoxia and inflammation. The relevance of these studies is questionable,
because of the fact that prohepcidin concentrations correlate with
neither urinary nor serum hepcidin concentrations, nor do they correlate
with relevant physiological responses (71, 81-83). Elderly people often suffer from anemia. Adv Hematol 2010;2010:750643.
REGULATION BY INFLAMMATION
Hepcidin in infectious and inflammatory diseases. These
include kidney tubule, heart, retina, monocytes, neutrophils, fat cells,
alveolar cells, pancreatic [beta]-cells, and cardiomyocardal cells
(20-27). Expression and localization of hepcidin in macrophages: a
role in host defense against tuberculosis. Crit
Care Med 2008;36:2388-94.
(57.) Chou ST, Weiss MJ. Plos One 2008;3:e4030
(12.) Kemna EH, Tjalsma H, Podust VN, Swinkels DW. Results are expected during 2011
(unpublished data).
(109.) Galesloot TE, Vermeulen SH, Geurts-Moespot AJ, Klaver SM,
Kroot JJ, van Tienoven D, et al. Targeting the hepcidin-ferroportin axis in the
diagnosis and treatment of anemias. Clin Chem 2007;53: 620-8.
(132.) Girelli D, Trombini P, Busti F, Campostrini N, Sandri M,
Pelucchi S, et al. It is possible that binding to [alpha]2-macroglobulin or
other carrier proteins prevents circulating hepcidin from being
freelyfiltered. Serum hepcidin is significantly associated
with iron absorption from food and supplemental sources in healthy young
women. J
Endocrinol 2005;184:361-70.
(41.) Theurl I, Theurl M, Seifert M, Mair S, Nairz M, Rumpold H, et
al. reported that transgenic hepcidin overexpression in
[beta]-thalassemia intermedia mice decreased iron overload, and even
ameliorated ineffective erythropoiesis (207).
Several reports suggest the potential use of hepcidin
concentrations in determining cardiovascular risk. The hypothesis that
erythropoietin (EPO) acts directly on hepatocyte receptors in cell
culture (51) could not be confirmed in animal models for anemia, which
showed that decreased hepcidin expression depends on erythropoiesis and
is not directly mediated by EPO (53, 54).
(44.) Hentze MW, Muckenthaler MU, Galy B, Camaschella C. STAT3 mediates hepatic hepcidin expression and its
inflammatory stimulation. Am J Physiol Lung
Cell Mol Physiol 2006;291:L417-25.
(197.) Ukarma L, Johannes H, Beyer U, Zaug M, Osterwalder B,
Scherhag A. Effect of body mass index reduction
on serum hepcidin levels and iron status in obese children. The
former defect leads to greater than normal ferroportin activity and thus
is often described as a "gain of function" ferroportin
mutation. Kidney Int 2010;78:769-73.
(63.) Mastrogiannaki M, Matak P, Keith B, Simon MC, Vaulont S,
Peyssonnaux C. J Clin Oncol 2011;29:e42.
Hepcidin has been demonstrated to be important in the pathogenesis
of other infectious agents as well. Hepcidin in obese children as a potential mediator
of the association between obesityand iron deficiency. (91)
SELDI-TOF MS Campostrini et al. Virtually all studies on hepcidin in CKD patients
revealed a strong positive relationship between hepcidin and ferritin
concentrations. Some studies report a weak, but
significant, negative correlation between serum hepcidin concentrations
and iron absorption (112, 146, 147). These conditions
include iron deficiency, hypoxia, anemia, and conditions characterized
by increased erythropoietic activity. This finding raises the
possibility that in this population hepcidin-independent mechanisms can
cause hypoferremia and anemia of inflammation, and/or that even
otherwise "normal" hepcidin concentrations are sufficient to
sustain anemia once it is initiated (162).
(101.) Kiernan UA, Tubbs KA, Gruber K, Nedelkov D, Niederkofler EE,
Williams P, Nelson RW. Possibly the consequent increase in hepcidin by
inflammatory signals attenuates iron toxicity than would otherwise be
observed in sickle cell disease patients (141, 143).
(100.) Butterfield AM, Luan P, Witcher DR, Manetta J, Murphy AT,
Wroblewski VJ, Konrad RJ. Hepcidin
expression is also increased byoxidative or endoplasmic reticulum stress. A number of exercise-generated mechanisms may
contribute to this low iron status of athletes, including hemolysis,
hematuria, sweating, and gastrointestinal bleeding (198). Other
groups have also reported reliable hepcidin assays that can be divided
in 3 main methodologies: (a)MS(85-95);(b) immunochemical assays,
comprising cRIA (96, 97), cELISA (13, 29, 98, 99), and a 2-site ELISA
(100); and (c) a ligand-binding assay (43) (Table 1). Perhaps, in such areas, untargeted
iron supplementation among iron-replete children might result in severe
adverse events by increasing the proliferation of latent pathogens
(158).
(205.) Pietrangelo A. Blood
2008;112:5241-4.
It is speculative, but conceivable, that under certain conditions
hepcidin escapes renal tubular reabsorption. These findings of increased
hepcidin concentrations led Peeling et al. Increased serum hepcidin and alterations in blood iron
parameters associated with asymptomatic P. Cumulative effects of consecutive running
sessions on hemolysis, inflammation and hepcidin activity. Moreover, in a previous study we found a relatively high
(pre)analytical variation for urine hepcidin measurements (107). Expression of the peptide hormone hepcidin increases in
cardiomyocytes under myocarditis and myocardial infarction. Hepcidin measurement also may be useful in
anticipating consequences of iron supplementation in infectious and
inflammatory diseases.
Hepcidin in Human Iron Disorders
Iron-depleted HFE C282Y patients have been shown to have very low
serum hepcidin concentrations, reflecting the combined effects of the
HFE mutation and phlebotomy on hepcidin expression (125, 132). J Am Soc Mass Spectrom 2010;21:1515-25.
(53.) Vokurka M, Krijt J, Sulc K, Necas E. Circ J 2010; 74:301-6.
DISORDERS ASSOCIATED WITH HEPCIDIN EXCESS
(39.) Sow FB, Florence WC, Satoskar AR, Schlesinger LS, Zwilling
BS, Lafuse WP. ER stress-inducible factor CHOP affects the expression
of hepcidin by modulating C/EBPalpha activity. Under low iron conditions, membrane-bound HJV is cleaved by
matriptase-2, a transmembrane protease serine 6, encoded bythe
transmembrane protease, serine 6 (TMPRSS6) [6] gene, expressed
predominantly in the liver (48, 49). Plasma hepcidin is a modest predictor of dietary iron
bioavailability in humans, whereas oral iron loading, measured by
stable-isotope appearance curves, increases plasma hepcidin. In a pediatric study, no relationship was found
between Helicobacter pylori infection and hepcidin and between cytokine
and hepcidin concentrations, suggesting that H. Recently,
several (199-201) but not all (202) studies showed increased urinary
hepcidin concentrations after exercise. Tohoku J Exp Med 2009;218:93-8.
(133.) Swinkels DW, Fleming RE Novel observations in hereditary
hemochromatosis: potential implications for clinical strategies.
Haematologica 2011;96:485-8.
(162.) Ferrucci L, Semba RD, Guralnik JM, Ershler WB, Bandinelli S,
Patel KV, et al. Characterization of the transition-metal-binding properties of
hepcidin. The serine protease matriptase-2 (TMPRSS6) inhibits hepcidin
activation by cleaving membrane hemojuvelin. Serum hepcidin-20 is elevated during the acute phase of myocardial
infarction. In anemia of multiple myeloma, hepcidin is induced by increased
bone morphogenetic protein 2. Immunochemical and
mass-spectrometry-based serum hepcidin assays for iron metabolism
disorders. In HD patients
on ESA, hepcidin did not predict which patients increase their
hemoblobin after iron loading (17). Pathways underlying iron accumulation in human nonalcoholic fatty
liver disease. Detection of serum hepcidin in renal failure and
inflammation by using ProteinChip System. Distinct requirements for Hfe in basal and induced hepcidin levels
in iron overload and inflammation. Hepatology 2011;53:1333-41.
Hepcidin in hereditary hemochromatosis (HH). Assessment of urinary concentrations of hepcidin provides
novel insight into disturbances in iron homeostasis during malarial
infection. Iron regulatory hormone hepcidin decreases in chronic
heart failure patients with anemia. These results suggest that
quantification of serum hepcidin concentrations could be a predictor for
the therapeutic effect of oral iron administration. We recently
assessed serum hepcidin reference intervals stratified by age and sex
stratified in a reference set selected from a large, well-phenotyped
sample of the general population of the Dutch city of Nijmegen (109). Gastroenterology 2007;132:294-300.
(35.) Nemeth E, Tuttle MS, Powelson J, Vaughn MB, Donovan A, Ward
DM. In small
studies in humans the fractional excretion of hepcidin has been
calculated to be as low as 0%-5% (29, 30), either because it is
reabsorbed, similarly to other small peptides, or because it is not
freely filtered. Fax +31-24-3668754; e-mail
d.swinkels@labgk.umcn.nl.
(218.) Poli M, Girelli D, Campostrini N, Maccarinelli F, Finazzi D,
Luscieti S, et al. At the same time it
should be noted that the relevance of measuring hepcidin-25 instead of
total hepcidin for clinical decision-making has not been systematically
investigated. Currently available hepcidin methods.
MS Reference
HPLC/UPLC (a) MS/MS Kobold et al. Conversely, the increased hepcidin
concentrations seen with inflammation might increase the virulence of
bacteria that depend on macrophage iron for their proliferation within
these cells (e.g., Salmonella and Mycobacteria spp.). Diseased red blood cells topple iron
balance. Serum hepcidin: reference ranges and
biochemical correlates in the general population. These hepcidin peptides form a hairpin structure, with 4
intramolecular disulfide bridges (Fig. Accurate determination of hepcidin concentrations in serum and
urine will improve our understanding of iron metabolism disorders and
may provide a useful tool in the differential diagnosis and clinical
management of such diseases.
At present, there is no single laboratory test that can
definitively distinguish ACD from IDA (160, 163). In sickle
cell disease, patients demonstrate the additional confounding factor of
inflammation. Therefore, the diagnostic
toolbox for hepcidin peptide measurements in animal models should be
improved and extended (75, 219, 222). Development of reference methods and
reference materials. N Engl J
Med 2005;352:1011-23.
(185.) Divakaran V, Mehta S, Yao D, Hassan S, Simpson S, Wiegerinck
E, et al. Role of alcohol in the regulation of iron
metabolism. Blood 2008;112:4292-7.
(183.) Amato A, Santoro N, Calabro P, Grandone A, Swinkels DW,
Perrone L, Miraglia Del Giudice E. HIF antagonists
are used in cancer to inhibit tumor angiogenesis (210). J Hepatol 2010;53: 941-9.
(106.) Forest JC, Burtis CA. This lack of reabsorption
may play a role in several disorders of iron metabolism that are
associated with tubular dysfunction and increased concentrations ofurine
hepcidin, such as inflammation, iron overload, and malaria (33, 34).
Possible local tubular production of hepcidin must also be taken into
account in the interpretation of urine as a mirror of serum hepcidin
concentrations in such studies (25) as well as possible defective
tubular reabsorption of hepcidin. ER stress controls iron metabolism through induction
of hepcidin. Nat Med 2007;13:1020-1.
Preclinical and clinical studies have also shown that hepcidin
antagonists such as hepcidin antibodies, BMP antagonists, cytokine
receptor antibodies, and HIF stabilizers can decrease hepcidin
expression and reverse iron abnormalities (208, 211-218).
(141.) Kroot JJ, Laarakkers CM, Kemna EH, Biemond BJ, Swinkels DW.
Regulation of serum hepcidin levels in sickle cell disease.
Haematologica 2009;94:885-7.
(26.) Gnana-Prakasam JP, Martin PM, Mysona BA, Roon P, Smith SB,
Ganapathy V. Humanized antiinterleukin-6 receptor antibody treatment
of multicentric Castleman disease. Biometals 2006;19: 527-33.
[4] Nonstandard abbreviations: AMI, acute myocardial infarction;
ACD, anemia of chronic disease; CKD, chronic kidney disease; RE,
reticuloendothelial; Tf-[Fe.sub.2], transferrin bound iron; TfR,
transferrin receptor; HFE, hemochromatosis iron protein; ERK/MAPK,
extracellular signal-regulated kinases/mitogen-activated protein kinase;
BMP/SMAD, bone morphogenetic protein/mothers against decapentaplegic
homolog (Drosophila); HJV, hemojuvelin; ESA, erythropoiesis-stimulating
agent; EPO, erythropoietin; GDF15, growth differentiation factor-15;
TWSG1, twisted gastrulation protein homolog-1; HIF, hypoxia inducible
factor; DMT, divalent metal transporter; IL, interleukin; C/EBP,
CCAAT-enhancer-binding protein; c, competitive; MS, mass spectrometry;
IDA, iron deficiency anemia; HH, hereditary hemochromatosis; HD,
hemodialysis.
(204.) Nemeth E. Inhibitors of the key initiators of the
cellular hypoxic response, such as prolyl hydroxylases, prevent
inactivation and degradation of HIF and as such maybe effective hepcidin
suppressors and restore natural iron regulation in anemia (220, 221).
In several early studies a commercial serum-based immunoassay was
used that measures the hepcidin precursor prohepcidin rather than the
bioactive peptide (80). The peptide hormone hepcidin interacts with the cellular
iron exporter ferroportin and thus is now recognized as the key
regulator of systemic iron homeostasis. Genes
that are regulated through E-boxes, including the clock genes period
homolog 1 (Drosophila) (PER1), timeless homolog (Drosophila) (TIMELESS),
and clock homolog (mouse) (CLOCK), tend to be under circadian rhythmic
transcriptional control. Daily regulation of serum and urinary hepcidin is not
influenced by submaximal cycling exercise in humans with normal iron
metabolism. Cell 2010;142:24-38.
Received May 10, 2011; accepted July 20, 2011.
(70.) Harrison-Findik DD. It has been
hypothesized that increased hepcidin concentrations may enhance
cardiovascular risk by increasing intracellular macrophage iron
concentrations and by increasing their atherogenic potential (186-189).
Furthermore, recent studies showed increased hepcidin production in
patients with (low-grade) inflammation, obesity, and nonalcoholic fatty
liver disease, which are traditionally associated with cardiovascular
disease (21, 144, 190, 191). Blood 2005; 106:2627-32.
(137.) Origa R, Galanello R, Ganz T, Giagu N, Maccioni L, Faa G,
Nemeth E.
(124.) Lee PL, Beutler E. Therefore, a
second Round Robin for plasma hepcidin was initiated to explore
word-wide hepcidin harmonization by exchanging synthetic materials for
assay harmonization and native samples. This latter variation is not surprising given
the absence of a reference method (106) and a validated commutable calibrator or other material for assay harmonization. However, there are 2 classes of
ferroportin mutations with different phenotypic consequences: loss of
hepcidin regulation and loss of ferroportin function (36, 128-130). Eur J Appl Physiol 2005;95:569-71.
(67.) Vecchi C, Montosi G, Zhang K, Lamberti I, Duncan SA, Kaufman
RJ, Pietrangelo A. High-throughput protein characterization using
mass spectrometric immunoassay. The first assays to
measure bioactive hepcidin-25 were an immunodot assay (59), SELDI-TOF
mass spectrometry (MS) (12, 15, 84). Blood Cells Mol Dis
2005;35:177-81.
(16.) Peters HP, Laarakkers CM, Swinkels DW, Wetzels JF. Determinants of hepcidin in patients on maintenance
hemodialysis: role of inflammation. Urinary hepcidin: an
inverse biomarker of acute kidney injury after cardiopulmonary bypass?
Curr Opin Crit Care [Epub ahead of print 2010 Aug 21].
Serum hepcidin concentrations appear to be determined by the
relative strengths of the individual regulators. In conclusion, hepcidin is a
promising diagnostic tool but efforts must be undertaken to assess the
relevance of specifically measuring hepcidin-25, to harmonize assay
outcomes throughout the world, to define clinical decision limits, and
to make assays available to clinical laboratories before hepcidin assays
can be fully included in clinical practice.
Concluding Remarks
(215.) Hashizume M, Uchiyama Y, Horai N, Tomosugi N, Mihara M.
Tocilizumab, a humanized antiinterleukin-6 receptor antibody, improved
anemia in monkey arthritis by suppressing IL-6-induced hepcidin
production. Plasma hepcidin levels are elevated but responsive to
erythropoietin therapy in renal disease. PLoS ONE 2008;3: e2706.
(60.) Peyssonnaux C, Zinkernagel AS, Schuepbach RA, Rankin E,
Vaulont S, Haase VH, et al. falciparum and P. Clearly, future large and
well-designed studies are needed to improve our understanding of this
hepcidin regulatory network in various disorders of iron metabolism.
(118.) Cherian S, Forbes DA, Cook AG, Sanfilippo FM, Kemna EH,
Swinkels DW, Burgner DP. Decreased serum hepcidin and improved
functional iron status 6 months after restrictive bariatric surgery.
Obesity 2010;18:2010-6.
Author Contributions: All authors confirmed they have contributed
to the intellectual content of this paper and have met the following 3
requirements: (a) significant contributions to the conception and
design, acquisition of data, or analysis and interpretation of data; (b)
drafting or revising the article for intellectual content; and (c) final
approval of the published article.
Hepcidin in sports medicine. Time-course analysis of
serum hepcidin, iron and cytokines in a C282Y homozygous patient with
Schnitzler's syndrome treated with IL-1 receptor antagonist.
Haematologica 2009;94:1297-300.
(72.) Lasocki S, Millot S, Andrieu V, Letteron P, Pilard N, Muzeau
F, et al. Natural and synthetic STAT3 inhibitors reduce
hepcidin expres sion in differentiated mouse hepatocytes expressing the
active phosphorylated STAT3 form. J Hepatol 2008;48: 801-10.
(96.) Busbridge M, Griffiths C, Ashby D, Gale D, Jayantha A,
Sanwaiya A, Chapman RS. J Clin Invest 2007;117:1933-9.
(1.) Krause A, Neitz S, Magert HJ, Schulz A, Forssmann WG,
Schulz-Knappe P, Adermann K. The low hepcidin state
relative to ferritin in these patients (125-127) leads to increased
intestinal iron absorption and body iron overload. This cleavage bymatriptase-2
weakens the BMP signaling.
(199.) Roecker L, Meier-Buttermilch R, Brechtel L, Nemeth E, Ganz
T. Nephrol Dial Transplant 2010;25:3996-4002.
https://www.thefreelibrary.com/Hepcidininhumanirondisorders:diagnosticimplications.-a0324761278
MS assays require relatively expensive equipment, but they have the
advantage of distinguishing between hepcidin-25, -22, and -20 (13).
ELISA assays will measure total hepcidin concentrations, with (depending
on the specificity of the antibody) different contributions from each of
these 3 isoforms. (99)
c-RIA Bushbridge et al. Immunoassays have the potential for more widespread use in
clinical laboratories. N Engl J Med 2009;361:1904-6.
Hepcidin in iron-loading anemias. For example, the
accumulation of hepcidin-22 and -20 isoforms may raise questions
regarding the interpretation that measured hepicidin concentrations
reflected bioactive hepcidin-25 in studies in which certain immunoassays
were used. Am J Nephrol 2010;31: 534-40.
(81.) Kemna E, Pickkers P, Nemeth E, van der Hoeven H, Swinkels D.
Time-course analysis of hepcidin, serum iron, and plasma cytokine levels
in humans injected with LPS. et al. Under
physiological conditions hepcidin-20 and hepcidin-22 are present in the
urine, but not, or at very low concentrations, in the serum (11-13).
Interestingly, these smaller hepcidin isoforms occur only in serum of
patients with diseases that are associated with increased concentrations
of hepcidin-25, such as acute myocardial infarction (AMI), [4] sepsis,
anemia of chronic disease (ACD), metabolic syndrome, and chronic kidney
disease (CKD) (Fig. Blood 2007;110:1048-54.
(127.) Papanikolaou G, Tzilianos M, Christakis JI, Bogdanos D,
Tsimirika K, MacFarlane J, et al. However,
the optimal target concentration of hemoglobin is debated, and many
patients become ESA resistant. Arterioscler Thromb Vasc Biol 2011;31:683-90.
Effect of iron administration on hepcidin concentrations. Also, heparin and heparin derivatives have
recently been shown to inhibit hepcidin expression in vitro and in vivo
by interfering with BMP signaling (218).
(29.) Ganz T, Olbina G, Girelli D, Nemeth E, Westerman M.
Immunoassay for human serum hepcidin. (13)
Swinkels et al. (30)
Anderson et al. Blood Cells Mol Dis
2009;43:169-79.
(28.) Peslova G, Petrak J, Kuzelova K, Hrdy I, Halada P, Kuchel PW,
et al. J Biol Chem 2002;277:37597-603.
(8.) Tselepis C, Ford SJ, McKie AT, Vogel W, Zoller H, Simpson RJ,
et al. Swinkels [1,2] *
Since the discovery of hepcidin 10 years ago, multiple studies have
contributed insights into the regulation of hepcidin and its functional
properties. Serum
hepcidin-25 levels in patients with chronic kidney disease are
independent of glomerular filtration rate. Expert Opin Ther Targets 2006;10:267-80.
In addition to its potential as a marker of iron metabolism in
patients with CKD, combined urinary and serum hepcidin concentrations
may serve as a marker for renal disease itself. Liver iron concentrations and urinary hepcidin in
beta-thalassemia. STAT3 is required for IL-6-gp130-dependent
activation of hepcidin in vivo. Training surface and intensity: inflammation,
hemolysis, and hepcidin expression. Br J Haematol 2009; 146:317-25.
In patients with heritable forms of anemia, information on hepcidin
concentrations may be valuable for identifying the most severely
affected patients and predicting and monitoring parenchymal iron
overload.
(150.) Hartman KR, Barker JA Microcytic anemia with iron
malabsorption: an inherited disorder of iron metabolism. Blood
2006;108:4237-45.
(98.) Koliaraki V, Marinou M, Vassilakopoulos TP, Vavourakis E,
Tsochatzis E, Pangalis GA, et al. The swinging pendulum of the anemia of cancer:
erythropoietin trumps hepcidin. Anal Biochem 2008;384:245-53.
(50.) Nicolas G, Viatte L, Bennoun M, Beaumont C, Kahn A, Vaulont
S. To allow proper interpretation of the effect of the
erythropoietic drive on hepcidin production, EPO and hepcidin
concentrations should be assessed simultaneously in selected patients
with anemia of CKD.
(122.) van Bokhoven MA, van Deursen CT, Swinkels DW. Hepcidin mediates transcriptional changes that modulate acute
cytokine-induced inflammatory responses in mice. Eur J Haematol
2009;83:595-602.
(18.) Rivera S, Nemeth E, Gabayan V, Lopez MA, Farshidi D, Ganz T.
Synthetic hepcidin causes rapid dose-dependent hypoferremia and is
concentrated in ferroportin-containing organs. Several
studies have addressed the relationship between iron absorption and
hepcidin concentrations. The
N-terminus of hepcidin is essential for its interaction with
ferroportin: structure-function study. Furin-mediated release
of soluble hemojuvelin: a new link between hypoxia and iron homeostasis.
Blood 2008;111:924-31.
Stock Ownership: None declared.
(79.) Hunter HN, Fulton DB, Ganz T, Vogel HJ. Measurement of serum hepcidin may prove to be useful as a
marker of iron dysregulation in these forms of iron overload.
(211.) Sasu BJ, Cooke KS, Arvedson TL, Plewa C, Ellison AR, Sheng J, et al. (13) (Bachem)
Ganz et al. Hepcidin-a potential novel biomarker for iron status in
chronic kidney disease. 4).
Circulating transferrin appears to be sensed via a hepatocellular
complex, which includes transferrin receptor-1 (TfR1), TfR2, and
hemochromatosis iron protein (HFE). For instance, studies
suggest that smaller increases in urinary hepcidin, relative to serum
hepcidin, maybe associated with a greater risk of acute kidney injury
after coronary artery bypass graft surgery in patients with stable renal
function (178, 179).Ina study on urine biomarkers in patients with lupus
nephritis, urinary concentrations of hepcidin, possibly secreted by
interstitial inflammatory cells, were identified as markers of renal
lupus nephritis flare (108).
(19.) Nemeth E, Preza GC, Jung CL, Kaplan J, Waring AJ, Ganz T. Biochem J 2008;413:553-7.
(51.) Pinto JP, Ribeiro S, Pontes H, Thowfeequ S, Tosh D, Carvalho
F, Porto G. In an attempt to
delineate relative strengths of these regulators in patients with iron
metabolism disorders, we constructed an algorithm to predict relative
hepcidin concentrations based on certain serum parameters (C-reactive
protein, Tf saturation, and soluble TfR) that reflect inflammation,
serum iron, and erythropoietic regulatory pathways (71). Blood 2007;109: 353-8.
(37.) Delaby C, Pilard N, Goncalves AS, Beaumont C, Canonne-Hergaux
F. Intra-individual
variability in serum hepcidin precludes its use as a marker of iron
status in hemodialysis patients. Blood 2009;113:3593-9.
FIRST-GENERATION (SEMIQUANTITATIVE) HEPCIDIN ASSAYS
(105.) Kroot JJ, Kemna EH, Bansal SS, Busbridge M, Campostrini N,
Girelli D, et al. Rapid Commun
Mass Spectrom 2007;21:4033-8.
(89.) Li H, Rose MJ, Tran L, Zhang J, Miranda LP, James CA, Sasu
BJ. SELDI-TOF-MS determination of hepcidin in clinical samples
using stable isotope labelled hepcidin as an internal standard. Clin J Am Soc Nephrol
2009;4:1331-7.
Circulating hepcidin was recently found to be bound to
[[alpha].sub.2]-macroglobulin with relatively high affinity and to
albumin with relatively low affinity. Haematologica 2008;93:90-7.
(176.) Kato A, Tsuji T, Luo J, Sakao Y, Yasuda H, Hishida A.
Association of prohepcidin and hepcidin-25 with erythropoietin response
and ferritin in hemodialysis patients Am J Nephrol 2008;28:115-21.
(22.) Nguyen NB, Callaghan KD, Ghio AJ, Haile DJ, Yang F. In healthy human volunteers hepcidin in urine
and serum increased upon oral iron dosing, although nonresponders were
reported (29, 59, 112, 145-147). Clin Chem 2009;55:1354-60.
(207.) Gardenghi S, Ramos P, Marongiu MF, Melchiori L, Breda L, Guy
E, et al. Iron homeostasis in mother and child during placental
malaria infection. (100)
Hepcidin binding
Q-TOF LC-MS Crockett et al. Development of a novel immunoassay for the iron
regulatory peptide hepcidin. The effects of erythropoetic activity and iron
burden on hepcidin expression in patients with thalassemia major.
Haematologica 2006;91:809-12.
The activation of the hepcidin regulatory pathways described above
are all dependent on interactions of circulating or autocrine factors
with hepatocyte membrane sensors to control the hepatic production of
hepcidin for proper maintenance of systemic iron homeostasis [reviewed
in (44)]. Trans R Soc
Trop Med Hyg 2010; 104:175-84.
[FIGURE 2 OMITTED]
Hepcidin Kinetics
(193.) Sharma S, Nemeth E, Chen YH, Goodnough J, Huston A, Roodman
GD, et al. Harmonization of the methodologies, by
using reliable calibrators or other materials for harmonization, will
enable translational scientists as well as physicians in clinical
practice around the world to collectively define criteria for the use of
hepcidin assays in diagnosis, staging, monitoring, and assessing
treatment indications of iron disorders.
(76.) Roy CN, Custodio AO, de Graaf J, Schneider S, Akpan I,
Montross LK, et al. Blood 2010;115: 3817-26.
(68.) Oliveira SJ, Pinto JP, Picarote G, Costa VM, Carvalho F,
Rangel M, et al. A crucial element in the maintenance of
systemic iron homeostasis is effective communication between cells that
absorb iron from the diet (duodenal enterocytes), use iron (mainly
erythroid precursors), and store iron (hepatocytes and tissue
macrophages). Regulation of type II transmembrane serine proteinase TMPRSS6
by hypoxia-inducible factors: new link between hypoxia signalling and
iron homeostasis. J Clin Invest
2004;113:1271-6.
Hepcidin-Modulating Agents
(13.) Kroot JJC, Laarakkers CM, Geurts-Moespot AJ, Grebenchtchikov
N, Pickkers P, van Ede AE, et al. Hepcidin in iron overload disorders.
Blood 2005; 105:4103-5.
Hepcidin in renal diseases. Although in vitro
studies suggest bacteriocidal effects of hepcidin, these effects would
require concentrations higher than those observed in the circulation.
Such concentrations may be achieved locally, for instance in phagosomes
of infected macrophages (39). Erythropoiesis requires considerable amounts of
iron, so suppression of hepatic hepcidin synthesis by erythropoietic
signals is of great physiological importance. Kidney Int 2009;76:912-3.
(148.) Finberg KE, Heeney MM, Campagna DR, Aydinok Y, Pearson HA,
Hartman KR, et al. These differences
in level assignment hinder the comparability of data collected by use of
the various methods and preclude the definition of universal reference
intervals and cutoff values for clinical decision making. Am J Clin Nutr
2009;89:1088-91.
(145.) Lin L, Valore EV, Nemeth E, Goodnough JB, Gabayan V, Ganz T.
Iron transferrin regulates hepcidin synthesis in primary hepatocyte
culture through hemojuvelin and BMP2/4. However, there are
indirect mechanisms by which HIFs may regulate hepcidin expression.
Increased HIF activity is associated with increased matriptase-mediated
cleavage hemojuvelin and thus decreased hepcidin expression (62).
Moreover, the systemic iron regulation by the hepcidin-ferroportin axis
acts in harmony with the enterocyte cellular iron homeostasis control
system. Hepcidin as a therapeutic tool to limit iron overload and
improve anemia in beta-thalassemic mice. Endocrinology 2007;148: 2663-8.
Hepcidin in cancer. Science 2004;306: 2090-3.
(139.) Malcovati L, Porta MGD, Laarakkers CM, Galli A, Albertini R,
Maffioli M, et al. Blood 2007; 110:2182-9.
(146.) Young MF, Glahn RP, riza-Nieto M, Inglis J, Olbina G,
Westerman M, O'Brien KO. However, this concern might be overcome by exploiting
antibodies that are hepcidin-25 specific (100). These findings again suggest that
the erythroid demand for iron might be a more powerful regulator of
hepcidin expression than inflammatory- or iron-induced hepcidin
formation. Eur J Clin Invest 2009;39: 883-90.
Interestingly, hepcidin also was evaluated as a predictor of ESA
response in several relatively small studies in humans. Pediatr Nephrol 1998;12:280-3.
(69.) Bridle K, Cheung TK, Murphy T, Walters M, Anderson G,
Crawford DG, Fletcher LM. Science 2009;325:877-80.
(55.) Tanno T, Bhanu NV, Oneal PA, Goh SH, Staker P, Lee YT, et al.
High levels of GDF15 in thalassemia suppress expression of the iron
regulatory protein hepcidin. A
novel TMPRSS6 mutation that prevents protease auto-activation causes
IRIDA. Hepcidin
concentrations in untreated patients with rare juvenile forms of HH tend
to be very low (127). Proinflammatory state, hepcidin, and anemia in older
persons. The pathogenesis of septic
acute renal failure. Plasma hepcidin concentrations significantly predict interindividual
variation in iron absorption in healthy men. Hepcidin biology and therapeutic applications.
Expert Rev Hematol 2010;3:153-5.
REGULATION BY IRON STATUS
REGULATION BY HYPOXIA
(102.) Nicolardi S, Palmblad M, Dalebout H, Bladergroen M,
Tollenaar RA, Deelder AM, van der Burgt YE. HFE mutations modulate the effect of iron on serum
hepcidin-25 in chronic hemodialysis patients. Development of a method for the sensitive and quantitative
determination of hepcidin in human serum using LC-MS/MS. Clin Chem 2010;56:1570-9.
(201.) Peeling P, Dawson B, Goodman C, Landers G, Wiegerinck ET,
Swinkels DW, Trinder D. J Infect Dis 2009;199:253-62.
Small hepcidin peptides have been shown to act as agonists in mice
in vivo on the basis of their amino-terminal domain (206). 3).
(172.) Kuragano T, Shimonaka Y, Kida A, Furuta M, Nanami M, Otaki
Y, et al. Elevated growth differentiation factor 15 expression
in patients with congenital dyserythropoietic anemia type I. Blood
2005;106: 3268-70.
REGULATION BY ERYTHROPOIETIC SIGNALS
(6.) Gerardi G, Biasiotto G, Santambrogio P, Zanella I, Ingrassia
R, Corrado M, et al. The
consequences of ineffective erythropoiesis on hepcidin expression thus
appear to trump the consequences of excessive iron stores. The gene encoding the iron regulatory peptide hepcidin is
regulated by anemia, hypoxia, and inflammation. Notably, monitoring of the bioactive serum hepcidin
during treatment by these hepcidin antagonists appears to be complicated
by the interference of the compounds in the assays (219).
(123.) Swinkels DW, Janssen MC, Bergmans J, Marx JJ. Hepcidin might thus be a mediator of the high incidence of iron
deficiency among athletes.
(85.) Murphy AT, Witcher DR, Luan P, Wroblewski VJ. On the basis of some
studies, investigators have reported that hepcidin binds divalent metals
([Cu.sup.2+], [Fe.sup.2+], [Zn.sup.2+], and [Ni.sup.2+]), but these
findings are inconsistent, e.g., some studies have suggested the
presence of iron in the core of the peptide in a tetrahedral sulfur
coordination (4-6), whereas others provide evidence for an
amino-terminal Cu(2+)-Ni(2+)-binding (ATCUN) motif (7, 8). Subsequent amino-terminal processing of the 25 amino acid
form can result in the appearance of 2 smaller hepcidin forms of 22 and
20 amino acids. Overweight children
have higher circulating hepcidin concentrations and lower iron status
but have dietary iron intakes and bioavailability comparable with normal
weight children. (90)
Altamura et al. A
metal-binding site is present in the amino terminal region of the
bioactive iron regulator hepcidin-25. Hepcidin: a new tool in the
management of anaemia in patients with chronic kidney disease? Nephrol
Dial Transplant 2008;23:2450-3.
(114.) Rehu M, Punnonen K, Ostland V, Heinonen S, Westerman M,
Pulkki K, Sankilampi U. Serum and liver iron differently regulate the bone
morphogenetic protein 6 (BMP6)-SMAD signaling pathway in mice.
Hepatology 2011;54:273-84.
(36.) De Domenico I, Ward DM, Nemeth E, Vaughn MB, Musci G, Ganz T,
Kaplan J. A time course of hepcidin response to iron challenge
in patients with HFE and TfR2 haemochromatosis. Nephrol Dial Transplant
2010;25:848-53.
(95.) Ward DG, Roberts K, Stonelake P, Goon P, Zampronio CG, Martin
A, et al. Blood 2010;116: 3635-44.
(83.) Roe MA, Spinks C, Heath AL, Harvey LJ, Foxall R, Wimperis J,
et al. Hepcidin, the iron watcher. Other studies have shown
that increased and/or ineffective erythropoiesis blunts the induction of
hepcidin by increased body iron stores (52, 73). As mentioned earlier, several
investigators have reported a decrease in hepcidin concentrations after
EPO administration (31, 50, 169, 170). (95)
Immunochemical
c-ELISA Kroot et al. Am J Hematol
1996;51:269-75.
(175.) Ford BA, Eby CS, Scott MG, Coyne DW. Am J Clin Nutr 2008;87:1374-83.
Hepcidin clearance is assumed to occur via cellular codegradation
with ferroportin at its sites of action, and via excretion by the
kidneys. Free Radic Biol Med 2007;42:492-8.
Although hepcidin is a promising companion diagnostic for ESA
therapy, patients with renal insufficiency are a rather complex
population in which consistent results have been difficult to obtain
(175). (85)
Murao et al. Clin
Chem 2006;52:950-68.
(156.) Nweneka CV, Doherty CP, Cox S, Prentice A. Because of its low molecular weight and small radius, unbound hepcidin is likely to freely pass into the glomerular filtrate. Metabolism
2005;54:453-9.
(159.) Drakesmith H, Prentice A. Cis and trans regulation of
hepcidin expression by upstream stimulatory factor. Most promising applications of serum
hepcidin in diagnostic medicine.
Disease condition Expected hepcidin
concentrations (a)
Classical Low, maybe compensated
hereditary by iron overload over
hemochromatosis time
Iron-loading Low, maybe compensated
anemias by transfusional iron
overload over time
Acquired forms of Miscellaneous
iron overload
Iron-refractory Inappropriately high
iron deficiency
anemia
Inflammation and High
infection
Chronic kidney High, decreases upon
diseases EPO treatment
Acute kidney Low (urine)
injury
Treatment with Depends on the disorder
hepcidin
antagonists and
agonists
Disease condition Potential added value
of hepcidin diagnostics
Classical Screen for the presence
hereditary of hemochromatosis
hemochromatosis
Predict which homozygotes
will be at risk for iron
overload
Determine the phlebotomy
interval
Prioritize genes to be
investigated
Iron-loading Identify the most
anemias severely affected
patients
Predict and monitor
(parenchymal) iron
overload
Acquired forms of A marker of iron
iron overload dysregulation
Iron-refractory Screen for primary defect
iron deficiency in hepcidin regulation
anemia
Inflammation and Differentiate ACD (b) and
infection IDA
Guide iron supplementation
therapy
Chronic kidney Predict EPO response
diseases
Guide treatment with EPO,
intravenous iron
Acute kidney Diagnose acute kidney
injury injury
Treatment with Monitor and assess
hepcidin indications
antagonists and
agonists
(a) In serum, unless stated otherwise.
(b) ACD, anemia of chronic disease; IDA, iron
deficiency anemia; EPO, erythropoietin.
(213.) Fatih N, Camberlein E, Island ML, Corlu A, Abgueguen E,
Detivaud L, et al. Int J Lab Hematol
2010;33:187-93.
(71.) Kemna EH, Kartikasari AE, van Tits LJ, Pickkers P, Tjalsma H,
Swinkels DW. Hepcidin, the hormone of iron metabolism, is bound specifically
to alpha-2-macroglobulin in blood. if you are handy you can probably replace the battery and or alternator in your car. The problem is that the problem with your vehicle might not be caused by the battery or the alternator! It might be a short in a wire, a bad ground or just a sticky relay that causes the battery to drain or the alternator to not charge the battery. That is why there are professional auto repair shops! http://www.ikev.org/haber/
stabilite/cd/08%201.7%20ICH%20Q2A%20for %20CD.pdf (Accessed June 2011).
REFERENCE INTERVALS FOR SERUM HEPCIDIN
(92.) Crockett DK, Kushnir MM, Phillips JD, Rockwood AL.
Time-of-flight mass spectrometry analysis of the ferroportin-hepcidin
binding domain complex for accurate mass confirmation of bioactive
hepcidin 25. Anal Biochem 2009;389:124-9.
Interpretation of hepcidin test results might be influenced by
whether the various assays are detecting freely circulating hepcidin,
hepcidin bound to a carrier protein, or both of these hepcidin species.
Lastly, the presence of hepcidin-22 and -20 isoforms, which play no role
in the regulation of iron metabolism, can interfere with the
quantification of hepcidin-25 in immunoassays that use antibodies that
react with all of these hepcidin isoforms.
(5.) Farnaud S, Rapisarda C, Bui T, Drake A, Cammack R, Evans RW.
Identification of an iron-hepcidin complex. Eur J Appl
Physiol 2009;106:51-9.
(138.) Tamary H, Shalev H, Perez-Vraham G, Zoldan M, Levi I,
Swinkels DW, et al. GDF15 and TWSG1 are
both BMP antagonists produced by erythroblasts and putative components
of the erythroid regulator that can inhibit hepcidin expression in
vitro. Gut
2004;53:735-43.
(112.) Roe MA, Collings R, Dainty JR, Swinkels DW, Fairweather-Tait
SJ. Furthermore, as the field moves toward
the use of hepcidin-related therapies, it should be realized that the
outcome of assays that are used to monitor the fate of hepcidin during
antihepcidin therapy may be affected by compounds that interfere with
hepcidin. The iron-regulatory peptide hormone hepcidin:
expression and cellular localization in the mammalian kidney. The
results of this study suggest that administration of antihepcidin
therapies alone or in combination with erythropoiesis-stimulating agents
may improve patients' erythropoietic response and allow the use of
lower EPO doses to avoid the potential detrimental effects of high EPO
concentrations. Most patients with iron-refractory
IDA are resistant to dietary iron supplementation, owing to a defect in
the TMPRSS6 gene encoding matriptase-2. Blood 2005;106: 1864-6.
(210.) Semenza GL. The ability
of hepcidin to bind iron and other divalent metals suggests there may be
a nonhormonal role for hepcidin in iron metabolism or a conformational
mechanism for uptake of divalent metals as part of hepcidin's
hormonal role in regulating ferroportin degradation.
(14.) Suzuki H, Toba K, Kato K, Ozawa T, Tomosugi N, Higuchi M, et
al. The hepcidin/ferritin ratio is also found to be
low in patients with these disorders (135, 137, 138, 140-142). The microcytic red cell and the anemia
of inflammation. Identification of TWSG1 as a second novel
erythroid regulator of hepcidin expression in murine and human cells.
Blood 2009;114:181-6.
Employment or Leadership: H. Infections are
associated with marked changes in iron homeostasis (152).
Malaria-associated anemia has been found to be associated with low serum
iron and increased hepcidin concentrations, causing iron withholding in
the RE system that ultimately leads to iron-restricted erythropoiesis
(115, 118, 153-156). J Endocrinol 2008;197:241-9.
(180.) Tussing-Humphreys LM, Nemeth E, Fantuzzi G, Freels S, Guzman
G, Holterman AX, Braunschweig C. Hepcidin expression in mouse retina and its regulation via
lipopolysaccharide/Toll-like receptor-4 pathway independent of Hfe.
Biochem J 2008;411:79-88.
Acknowledgments: We thank Mirian Janssen and Paul Brons and the
members of the Dutch HEPCIKID (HEPCIdin in patients with KIdney Disease)
consortium, Jack Wetzels, Carlo Gaillard, Roos Masereeuw, Jaap Joles,
and Hilde Peters, for useful discussions on the diagnostic potential for
hepcidin measurements in clinical practice; Fred Sweep, Alec Ross, Guus
Kortman, Rieneke Terink, Susanne van Santen, Lucas van Eijk, Tessel
Galesloot, Louise de Swart, Charlotte Schaap, Erwin Wiegerinck, Coby
Laarakkers, Siem Klaver, Rian Roelofs, Anneke Geurts-Moespot, Nicolai
Grebenchtchikov, and other members of the Nijmegen Iron Group for
stimulating discussions on hepcidin methodology and its clinical
utility; Hans Willems for discussion on assay harmonization; and Hanka
Venselaar and Erwin Kemna for their contribution to the figures.
(140.) Casanovas G, Swinkels DW, Altamura S, Schwarz K, Laarakkers
CM, Gross HJ, et al. Anemia of inflammation: the cytokine-hepcidin
link. Blood
2009;113:5277-86.
The functional signaling routes by which (a) iron status, (b)
erythropoietic activity, (c) hypoxia, and (d) inflammation affect
hepcidin expression are increasingly being investigated. ASH Annu
Meeting Abstracts 2008;112:2676.
(62.) Lakhal S, Schoedel J, Townsend AR, Pugh CW, Ratcliffe PJ,
Mole DR. A decrease in hepcidin results in
the release of stored iron and an increase in dietary iron absorption.
On the other hand, infection and inflammation cause an increase in
hepcidin synthesis. Thus, in chronic mild inflammatory
conditions, such as obesity or the metabolic syndrome, even a mild
hepcidin excess may be sufficient to alter the balance between iron loss
and iron uptake toward iron deficiency.
Much is still unknown on the origin of the smaller isoforms of
hepcidin, although data suggest that calcium-independent tissue activity
in pancreas extracts might lead to the systemic N-terminal truncation of
hepcidin-25 to hepcidin-22, and that dipeptidylpeptidase 4 is involved
in the processing of hepcidin-22 into hepcidin-20 (9, 10). J
Biol Chem 2009;284:24155-67.
In ACD, IL-6 and other cytokines induce hepcidin concentrations,
resulting in iron sequestration in macrophages and leading to
hypoferremia. Nat Rev Microbiol 2008;6: 541-52.
(220.) Braliou GG, Verga Falzacappa MV, Chachami G, Casanovas G,
Muckenthaler MU, Simos G. Results of the first international round robin for the
quantification of urinary and plasma hepcidin assays: need for
standardization. These promises brought about a large series of
studies that examined hepcidin concentrations in patients with CKD. Soon after its discovery and during the
years thereafter, hepcidin was recognized as potentially relevant in CKD
because it may be responsible for the often-observed imbalance between
iron homeostasis and ESA resistance (50, 166). This apparent circadian rhythm of hepcidin
concentrations may be regulated by transcription factors such as
upstream stimulatory factor and c-Myc/Max through E-boxes (110). Blood
2006;108:3730-5.
(47.) Babitt JL, Huang FW, Wrighting DM, Xia Y, Sidis Y, Samad TA,
et al. Some of these studies also demonstrated correlations
between hepcidin and iron or transferrin saturation (169, 170). Subsequently, iron availability for the erythron becomes
limiting and contributes to the development of ACD (59, 75, 81, 160,
161). Haematologica 2007;92:583-8
Decreased hepcidin expression has been reported in response to
hypoxia in vivo (58, 59). Increased adipose tissue expression of hepcidin in severe obesity is
independent from diabetes and NASH. Is
hepcidin-25 a clinically relevant parameter for the iron status in
hemodialysis patients? J Ren Nutr 2010;20:S77-83.
[FIGURE 3 OMITTED]
(15.) Tomosugi N, Kawabata H, Wakatabe R, Higuchi M, Yamaya H,
Umehara H, Ishikawa I. J Biomed
Biotechnol 2010;2010:329646.
Hepcidin in iron-refractory IDA. This algorithm
provided insight into the interrelation of these pathways by showing
that hepcidin inhibition by erythropoiesis strongly interferes with
hepcidin upregulation by iron and that inflammation strongly increases
hepcidin regardless of iron status and erythropoietic activity. IL-6 mediates hypoferremia of inflammation by inducing the
synthesis of the iron regulatory hormone hepcidin. In these
conditions, dysregulation of hepcidin synthesis as a consequence of
reactive oxygen species, endoplasmic reticulum stress, and cytokine tumor necrosis factor-[alpha]-mediated pathways may contribute to
relatively decreased hepcidin synthesis and iron accumulation (59,
67-70, 144). However, how
erythropoiesis regulates hepcidin is not clear yet. In
addition, hepcidin's potential to become a target of treatment was
quickly acknowledged. Anti-interleukin 6 receptor antibody tocilizumab reduces the
level of serum hepcidin in patients with multicentric Castleman's
disease. These
molecules, like BMPs are members of the transforming growth
factor-[beta] family and thus possibly act through effects on the
BMP/SMAD pathway (Fig. Serum hepcidin concentrations decreased, and an increase
in iron status and intestinal absorption was observed in individuals
with weight loss (182, 183). Blood
2005;106:1092-7.
(43.) De Domenico I, Nemeth E, Nelson JM, Phillips JD, Ajioka RS,
Kay MS, et al. However, MS methods can also be
automated (101, 102), and would have to be optimized for hepcidin
because its amphiphatic character makes it readily stick to laboratory
plastics, especially when relatively small sample volumes are used in
large tubes.
(42.) Keel SB, Abkowitz JL. 4).
(10.) Valore EV, Ganz T. Blood 2010;115:3810-6.
Further comparison of the analytical characteristics of various
published assays is incomplete, because not all studies have reported
these characteristics in accordance with the STARD (STAndards for the
Reporting of Diagnostic accuracy studies) procedures (103) or validated
the reported assays according to recommendations of the International
Conference of the Harmonization (ICH) of analytical procedures (104).
Nonetheless, the scientific and medical community was informed on the
status and agreement of the current hepcidin methods by a recent
international send-out of samples for urine and serum hepcidin
measurement in 2009, the so-called "Round Robin 1." In this
study the correlations between the participating methods were generally
high and the between-sample and analytical variation of most methods
were similar (105). (97)
Sandwich ELISA Butterfield et al. Moreover, hepcidin concentrations in these patients
were associated with increased concentrations of monocyte
chemoattractantprotein-1 and vascular damage. Blood Cells Mol Dis 2010;44:16-21.
(80.) Kulaksiz H, Gehrke SG, Janetzko A, Rost D, Bruckner T,
Kallinowski B, Stremmel W. Autocrine formation of hepcidin induces iron retention in human
monocytes. 1), and the high degree of conservation of
hepcidin among a wide range of species, which diminishes the elicitation
of an immune response in host animals (50).
(212.) Yu PB, Hong CC, Sachidanandan C, Babitt JL, Deng DY, Hoyng
SA, et al. Furthermore, sample throughput is likely to be
higher for ELISA than for MS assays. Quantitation of hepcidin in serum using
ultra-high-pressure liquid chromatography and a linear ion trap mass
spectrometer. There are multiple potential opportunities for cross
communication among these pathways, and experimental evidence shows that
these pathways do not function completely independently of each other.
Anti-IL-6-receptor antibody (tocilizumab) was shown to suppress
IL-6-induced hepcidin production in Castleman disease (a rare disorders
with systematic inflammation and anemia), and it improved anemia in
arthritic monkeys (214-217). 4) (55-57). Eur J Appl Physiol 2010;110: 877-83.
(167.) Viatte L, Vaulont S. Possibly, these increased hepcidin concentrations
might be advantageous in the protection against extracellular growing
microorganisms by decreasing the extracellular supply of iron. 3) [reviewed in (44)]. Best
Pract Res Clin Gastroenterol 2009;23:171-83.
(86.) Murao N, Ishigai M, Yasuno H, Shimonaka Y, Aso Y. Clin Chem
2008;54:1584-6.
(191.) Aigner E, Theurl I, Theurl M, Lederer D, Haufe H, Dietze O,
et al. Br J Biomed Sci 2009; 66:150-7.
SECOND-GENERATION (QUANTITATIVE) HEPCIDIN ASSAYS
(94.) Altamura S, Kiss J, Blattmann C, Gilles W, Muckenthaler MU.
SELDI-TOF MS detection of urinary hepcidin. However, because the defect is downstream of
hepcidin, these patients do not have low hepcidin concentrations. Biochem J 2010;427:289-96.
(111.) Bozzini C, Campostrini N, Trombini P, Nemeth E, Castagna A,
Tenuti I, et al. As such, we recommend standardization of
sampling time to minimize within-individual and (pre)analytical
variability in clinical studies exploiting hepcidin measurements.
Hepcidin in IDA. Dorsomorphin inhibits BMP signals required for embryogenesis and iron metabolism. Am
J Kidney Dis 2009;53: 584-95.
Authors' Disclosures or Potential Conflicts of Interest: Upon
manuscript submission, all authors completed the Disclosures of
Potential Conflict of Interest form. Haematologica
2010;95:1660-7.
(143.) Porter JB. J Nutr
Biochem 2010;21:749-56.
(84.) Kemna E, Tjalsma H, Laarakkers C, Nemeth E, Willems H,
Swinkels D. neutralized hepcidin by
a monoclonal antibody in the Brucella abortus mouse model of anemia of
inflammation and found it to restore responsiveness to EPO (211). However, in this study increased hepcidin
concentrations appeared insufficient for the development of anemia
(195), suggesting that compensation by increased erythropoiesis through
increased EPO production may explain the lack of anemia in cancer
despite increased hepcidin concentrations (196).
Hepcidin in heart diseases. Clin Chem 2003;49:19-20.
(38.) Ramey G, Deschemin JC, Durel B, Canonne-Hergaux F, Nicolas G,
Vaulont S. Eur J Appl Physiol 2009;106:435-43.
(216.) Nishimoto N, Kanakura Y, Aozasa K, Johkoh T, Nakamura M,
Nakano S, et al. Maternal serum hepcidin is low at term and
independent of cord blood iron status. 4). Hereditary
hemochromatosis due to resistance to hepcidin: high hepcidin
concentrations in a family with C326S ferroportin mutation. Iron and its relation to immunity and
infectious disease. J Pharmacol
Toxicol Methods 2009;59:171-80.
(135.) Gardenghi S, Marongiu MF, Ramos P, Guy E, Breda L, Chadburn
A, et al. Alternatively, the otherwise expected increased
circulating concentrations in patients with decreased renal filtration
may be offset by a compensatory feedback decrease in hepatic hepcidin
production.
The increase in hepcidin expression with inflammation is primarily
mediated by interleukin-6 (IL-6). Eur J Appl Physiol 2008;103:
381-91.
(4.) Farnaud S, Patel A, Evans RW. Gastroenterology 2006;131:788-96.
(184.) Matsumoto M, Tsujino T, Lee-Kawabata M, Naito Y, Akahori H,
Sakoda T, et al. The solution
structure of human hepcidin, a peptide hormone with antimicrobial
activity that is involved in iron uptake and hereditary hemochro
matosis. Int J Obes
2010;34:1772-4.
(125.) van Dijk BA, Laarakkers CM, Klaver SM, Jacobs EM, van Tits
LJ, Janssen MC, Swinkels DW. Lancet 2006;367:133-43.
(128.) Sham RL, Phatak PD, Nemeth E, GanzT. One study
revealed that hepcidin concentrations of EPO responders did not differ
from those of hyporesponders (176), whereas cross-sectional studies
among HD patients and a prospective study among patients with combined
CKD and chronic heart failure revealed that nonresponders had low
hepcidin concentrations (32, 170, 177). Hepcidin is not useful as a biomarker for iron needs
in haemodialysis patients on maintenance erythropoiesis-stimulating
agents. LEAP-1, a novel highly disulfide-bonded
human peptide, exhibits antimicrobial activity. Future studies are needed to
assess the position of hepcidin in clinical decision making in these
patients.
(174.) Zaritsky J, Young B, Gales B, Wang HJ, Rastogi A, Westerman
M, et al. Iron absorption in dysmetabolic iron overload syndrome is
decreased and correlates with increased plasma hepcidin. J Clin Invest 2004;113: 1251-3.
Hepcidin Function
(206.) Nemeth E. Hepcidin in the management of
patients with mild nonhemochromatotic iron overload: fact or fiction? J
Hepatol 2008;49:680-5.
Hepcidin measurements appear to have potential utility in
diagnostic algorithms to distinguish IDA from ACD and the combined
presence of IDA/ACD. Blood 2010;
116:3627-34.
(46.) Corradini E, Meynard D, Wu Q, Chen S, Ventura P, Pietrangelo
A, Babitt JL. J Clin Invest
2010;120:2395-405.
(151.) Beutler E, Van GC, te Loo DM, Gelbart T, Crain K, Truksa J,
Lee PL. Hepcidin in anemia of chronic heart failure. Measurement of urinary hepcidin levels by SELDI-TOF-MS
in HFE hemochromatosis. The hepcidin produced by these cells, however, is unlikely to
make a significant contribution to systemic circulating concentrations,
but may exert local effects in these tissues (see below).
(66.) Pietrangelo A, Dierssen U, Valli L, Garuti C, Rump A,
Corradini E, et al. Am J
Clin Nutr 2010; 92:1385-92.
Hepcidin produced by various cell types other than hepatocytes (see
above) may have local effects in these tissues. Br J Haematol 2008;142:979-85.
(30.) Swinkels DW, Girelli D, Laarakkers C, Kroot J, Campostrini N,
Kemna EH, Tjalsma H. In this study serum hepcidin was strongly associated with serum
ferritin in men and women, confirming findings of smaller previous
studies (29, 30, 107, 111, 112). Down-regulation of hepcidin resulting from long-term
treatment with an anti-IL-6 receptor antibody (tocilizumab) improves
anemia of inflammation in multicentric Castleman disease. Hepcidin mRNA levels in
mouse liver respond to inhibition of erythropoiesis. Impaired intestinal iron absorption in Crohn's
disease correlates with disease activity and markers of inflammation.
Inflamm Bowel Dis 2006;12: 1101-6.
Since the discovery of hepcidin, there has been a substantial
interest in developing a reliable assay of the peptide hormone in body
fluids. A novel immunological assay for
hepcidin quantification in human serum. Blood 2006;108:1381-7.
Hepcidin-25 is thought to be the major regulator of dietary iron
absorption and cellular iron release. Br J Nutr 2007;97:544-9.
(104.) ICH Steering Committee. Biochimie 2009;91:1335-8.
DISORDERS ASSOCIATED WITH HEPCIDIN DEFICIENCY
(73.) Huang H, Constante M, Layoun A, Santos MM. In patients with hepatitis C virus,
increased transferrin saturation and increased concentrations of serum
ferritin and hepatic iron have been observed. These
findings are corroborated by in vitro studies that showed that the
truncated 22 amino acid and 20 amino acid forms have greatly diminished
and almost complete loss of ferroportin regulatory activity,
respectively, compared with 25 amino acid hepcidin (19).
In addition to its role in regulating systemic iron metabolism,
hepcidin may also contribute to host defense. After
treatment with phlebotomy that normalized iron stores (as assessed by
serum ferritin), these patients have been found to have serum hepcidin
concentrations or serum hepcidin/ferritin ratios within or above
reference intervals (128, 131). Effects of routine
(2.) Pigeon C, Ilyin G, Courselaud B, Leroyer P, Turlin B, Brissot
P, Loreal O. The
low-grade inflammation in obese and dysmetabolic iron overload syndrome
patients, (characterized by the association of increased body iron
stores and metabolic features), is associated with increased hepcidin
concentrations, leading to poor iron absorption and causing ACD (116,
117, 180, 181). Plos One 2009;4: e4581.
(75.) Theurl I, Aigner E, Theurl M, Nairz M, Seifert M, Schroll A,
et al. In congenital iron-loading
anemias, such as [beta]-thalassemia (major and intermedia) and
congenital dyserythropoietic anemia I and II, but also in acquired forms
such as myelodys-plastic syndrome types RA (refractory anemia) and RARS (RA with ringed sideroblasts), the diseased erythron dysregulates iron
homeostasis by inhibiting hepcidin synthesis, even in the presence of
iron overload (134-140). Iron-regulatory protein hepcidin is increased in female athletes
after a marathon. Serum
pro-hepcidin: measuring active hepcidin or a non-functional precursor?
Gut 2005;54: 169-70.
Research Funding: None declared.
References
(192.) Valenti L, Dongiovanni P, Motta BM, Swinkels DW, Bonara P,
Rametta R, et al. Am J Clin Nutr 2009; 89:533-8.
As we discussed previously, basal hepcidin concentrations greatly
depend on the applied measurement method (105). Renal tubular function in
betathalassemia. Anal Chem 2010;82:1551-5.
[6] Human genes: TMPRSS6, transmembrane protease, serine 6; HFE,
hemochromatosis; PER1, period homolog 1 (Drosophila); TIMELESS, timeless
homolog (Drosophila); CLOCK, clock homolog (mouse); HAMP, hepcidin
antimicrobial peptide; TFR2, transferrin receptor 2; HFE2,
hemochromatosis type 2 (juvenile).
(188.) Sullivan JL. The
IL-6-independent pathway may be attributed to increased BMP-2
concentrations, which have been suggested to act synergistically with
IL-6 to induce hepatocyte hepcidin synthesis (193, 194).
(108.) Zhang X, Jin M, Wu H, Nadasdy T, Nadasdy G, Harris N, et al.
Biomarkers of lupus nephritis determined by serial urine proteomics.
Kidney Int 2008;74:799-807.
(171.) Valenti L, Girelli D, Valenti GF, Castagna A, Como G,
Campostrini N, et al. FEBS Lett
2000;480:147-50.
(155.) Howard CT, McKakpo US, Quakyi IA, Bosompem KM, Addison EA,
Sun K, et al. Hepcidin targets ferroportin for degradation in hepatocytes.
Haematologica 2010;95:501-4.
(147.) Zimmermann MB, Troesch B, Biebinger R, Egli I, Zeder C,
Hurrell RF. J Hepatol 2011;54: 173-81.
In recent years, substantial progress has been made by the
introduction of an internal standard to quantify hepcidin-25 in serum
and urine by an updated TOF-MS assay (13, 30). Ineffective erythropoiesis in beta-thalassemia is
characterized by increased iron absorption mediated by downregulation of
hepcidin and up-regulation of ferroportin. One study showed a blunted hepcidin response to
inflammatory stimuli in hemochromatosis (HFE) knock-out mice (76),
whereas results of other studies of the same mice or a patient with an
HFE mutation suggest that inflammatory induction of hepcidin is
independent from the HFE protein (77, 78). Additional studies to investigate the
possibility that local urinary infections or tubular dysfunction can
contribute to hepcidinuria are warranted.
(32.) Costa E, Swinkels DW, Laarakkers CM, Rocha-Pereira P, Rocha
S, Reis F. Cellular iron is mostly bound
within iron protoporphyrin (heme) and iron--sulfur clusters, which serve
as enzyme cofactors, or stored within the core of ferritin multimers.
Without adequate iron, cells lose their capacity for electron transport and energy metabolism. (Pre) analytical imprecision, between-subject
variability, and daily variations in serum and urine hepcidin:
implications for clinical studies. Blood 2007;109:5027-35.
(129.) Drakesmith H, Schimanski LM, Ormerod E, Merryweather-Clarke
AT, Viprakasit V, Edwards JP, et al. The first reliable assays to quantify hepcidin in human body
fluids have recently been developed, and proof-of-principle studies in
human iron disorders highlight hepcidin as a promising novel tool in
diagnostic medicine, as outlined in Table 2. As such hepcidin was
described as a promising companion diagnostic marker to predict ESA
responsiveness, and to guide treatment with ESA and intravenous iron. We
conclude by highlighting the most promising applications of hepcidin
assays in diagnostic medicine.
Preclinical studies and some clinical studies have provided
proof-of-concept for synthetic hepcidin-25, small hepcidin peptides, BMP
agonists, and HIF stabilizers to prevent iron overload attributed to
hepcidin deficiency.
(24.) Kulaksiz H, Fein E, Redecker P, Stremmel W, Adler G, Cetin Y.
Pancreatic beta-cells express hepcidin, an iron-uptake regulatory
peptide. Clin J Am Soc Nephrol 2010;5: 1010-4.
(110.) Bayele HK, McArdle H, Srai SK. Moreover, hepcidin was found to modulate
lipopolysaccharide-induced transcription in both cultured macrophages
and in vivo mouse models (40). 2-Oxoglutarate-dependent oxygenases control
hepcidin gene expression. Heparin: a potent inhibitor of hepcidin expression in
vitro and in vivo. Regulation of hepcidin: Insights from biochemical analyses
on human serum samples. Therefore, there is need
for further studies on serum hepcidin concentrations in larger and
well-designed studies to resolve the aforementioned discrepancies in the
literature.
(158.) Sazawal S, Black RE, Ramsan M, Chwaya HM, Stoltzfus RJ,
Dutta A, et al. Development of novel therapeutic strategies that
target HIF-1. Eur J Heart Fail
2010;12:943-50.
Urine hepcidin measurements may be attractive, especially for use
in research and measurements in children and patients in the
underdeveloped world, because this matrix allows noninvasive sampling.
Nevertheless, although a significant relationship was found between the
hepcidin concentrations of urine-serum sample pairs from healthy
controls and patients with disorders of iron metabolism (12, 29, 107),
urine hepcidin concentrations may not always accurately reflect serum
hepcidin concentrations. Primaire hemochromatose door
ferroportinegenmutaties: is er een plaats voor hepcidine in de
diagnostiek? Ned Tijdschr Klin Chem Labgeneesk 2011;36:6-11.
HEPCIDIN ANTAGONISTS
(103.) Bruns DE. Hepcidin, a urinary
antimicrobial peptide synthesized in the liver. Supraphysiological doses of exogenous BMP-6 for 10 days also were
reported to improve hepcidin deficiency, reduce serum iron, and
redistribute tissue iron to appropriate storage sites (RE macrophages,
spleen) in a mouse model for HFE hemochromatosis (209). Furthermore, CRP and IL-6 were shown
to be less relevant predictors in the setting of renal insufficiency
(16,170,172-175). Of the currently
available commercial immunochemical research kits for serum hepcidin, we
found the RIA and enzyme-immunoassay kits of Bachem (purchased November
2009 and August 2010, respectively) to be suitable to differentiate
between hepcidin concentrations in serum samples of controls and
patients with various iron disorders, whereas the bioactive hepcidin kit
of DRG Instruments, (purchased October 2009) gave similar concentrations
for all samples and could not discriminate between iron metabolism
disorders (unpublished results).
(195.) Hohaus S, Massini G, Giachelia M, Vannata B, Bozzoli V,
Cuccaro A, et al. However, absolute hepcidin concentrations differed
widely between the assays. Proteome Sci 2008;6:28.
CHALLENGES FOR HEPCIDIN ASSAYS
(117.) Aeberli I, Hurrell RF, Zimmermann MB. Elevated systemic hepcidin and iron
depletion in obese premenopausal females. Correlations between the expression
of TWSG1 expression and serum iron parameters and serum hepcidin
concentrations have not yet been determined in humans. Suppression of
hepcidin during anemia requires erythropoietic activity. Evidence for distinct pathways of hepcidin regulation by acute
and chronic iron loading in mice. Regulation of iron homeostasis in anemia of chronic disease and
iron deficiency anemia: diagnostic and therapeutic implications. Hepcidin: a putative iron-regulatory
hormone relevant to hereditary hemochromatosis and the anemia of chronic
disease. Eur J Haematol 2010; 85:345-52.
prophylactic supplementation with iron and folic acid on admission
to hospital and mortalityin preschool children in a high malaria
transmission setting: community-based, randomised, placebo-controlled
trial. (98)
Schwarz et al. An Hfe-dependent pathway mediates hyposideremia in
response to lipopolysaccharide-induced inflammation in mice. BMP-2 administration in mice was found to increase
liver hepcidin expression and reduce serum iron concentrations in vivo
(208). Clin J Am Soc Nephrol 2009;4:1051-6.
(208.) Babitt JL, Huang FW, Xia Y, Sidis Y, Andrews NC, Lin HY.
Modulation of bone morphogenetic protein signaling in vivo regulates
systemic iron balance. Advances in quantitative hepcidin measurements by
time-of-flight mass spectrometry. Because these patients tend to be anemic, even a mild
hepcidin excess can be considered to be inappropriately high for the
level of anemia. A novel mono clonal antibody immunoassay for the
detection of human serum hepcidin. Blood 2006;108:3204-9.
There is an increasing demand for preclinical tools to assess the
efficacy of hepcidin-related therapies. Adipose tissue is an active
endocrine organ that releases several cytokines and adipokines, which
can contribute to the development of a low-grade systemic inflammation.
Furthermore, adipose tissue also can produce hepcidin (21). BMJ 2011;342:c7251.
Iron is required for the function of oxygen-binding molecules,
mainly hemoglobin and myoglobin, and iron-containing enzymes, including
the cytochrome system in mitochondria. Hepcidin is down-regulated in alcoholic liver
injury: implications for the pathogenesis of alcoholic liver disease.
Alcohol Clin Exp Res 2006;30: 106-12.
(3.) Jordan JB, Poppe L, Haniu M, Arvedson T, Syed R, Li V, et al.
Hepcidin revisited, disulfide connectivity, dynamics, and structure. This
situation suggests that reference intervals may have limitations when
used for the interpretation of individual hepcidin concentrations. Antihepcidin antibody treatment modulates iron metabolism and
is effective in a mouse model of inflammation-induced anemia. Hepcidin and iron-related gene expression in
subjects with Dysmetabolic Hepatic Iron Overload. The authors concluded that hepcidin-20, rather than
hepcidin-25, may be helpful for the diagnosis of acute myocardial
infarction (14).
(99.) Schwarz P, Strnad P, von FG, Janetzko A, Krayenbuhl P, Adler
G, Kulaksiz H. Quantification of hepcidin-25 in human serum by
isotope dilution micro-HPLC-tandem mass spectrometry. Haematologica 2009; 94:1748-52.
(181.) Ruivard M, Laine F, Ganz T, Olbina G, Westerman M, Nemeth E,
et al. Therefore,
differentiation between these conditions is often achieved by combining
various biochemical markers of iron metabolism. http://www.ifcc.org/
index.asp?cat=Publications&scat=eJIFCC_&suba =
VoL13_No_3&subx=Development_Of_Reference_
Methcds_And_Reference_Materials_byJean-Claude_
Forest_Cari_A_Burtis&zip=1&dove=1&zona=full&
numero=&aq=1 (Accessed October 2011).
Hepcidin concentrations can also be induced by targeting the BMP
pathway (Fig. (94)
Ward et al. Blood
2008;111:5727-33.
(214.) Song SN, Tomosugi N, Kawabata H, Ishikawa T, Nishikawa T,
Yoshizaki K. This increased synthesis leads to a deficiency of
iron available for erythropoiesis, and is considered to be the mechanism
underlying reticuloendothelial (RE) iron sequestration, intestinal iron
absorption impairment, and low serum iron concentrations characteristic
of anemia of chronic disease.
(222.) Tjalsma H, Laarakkers CM, van Swelm RP, Theurl M, Theurl I,
Kemna EH, et al. Hepcidin was originally
identified as an antimicrobial peptide (1, 11). Fleming, [3]
and Dorine W. J Biol Chem 2001;276:7811-9.
(87.) Kobold U, Dulffer T, Dangl M, Escherich A, Kubbies M,
Roddiger R, Wright JA. Viral infection and iron
metabolism. The relatively high hepcidin
concentrations in some patients might be a consequence of the
transferrin saturation that remained increased despite phlebotomy. On the basis of theoretical
calculations, 11% of hepcidin was estimated to be freely circulating
(28). Additional data were reported that
suggested an atherogenic function of hepcidin in a study that revealed
that ex vivo hepcidin-25 treatment of differentiating monocytes from
patients with the metabolic syndrome induced monocyte chemoattractant protein-1 (192). Quantitation of
hepcidin from human and mouse serum using liquid chromatography tandem
mass spectrometry. Blood 2005;106: 3979-84.
(119.) Altamura S, D'Alessio F, Selle B, Muckenthaler MU. J Gastroenterol 2011; 46:648-56.
(190.) Barisani D, Pelucchi S, Mariani R, Galimberti S, Trombini P,
Fumagalli D, et al. In IDA patients, and also in patients with low
ferritin concentrations without anemia, secondary to blood losses or
insufficient dietary intake, hepcidin concentrations have been found to
be very low, often below the lower limit of detection of the employed
assays (13, 29).
(144.) Swinkels DW, Drenth JP. J Mol Med 2011.
[FIGURE 4 OMITTED]
(91.) Anderson DS, Heeney MM, Roth U, Menzel C, Fleming MD, Steen
H. Evidence for the latter explanation comes from the
finding of increases of only 1- to 6-fold of serum hepcidin
concentrations in patients with glomerular dysfunction (15, 16, 29, 31,
32) compared with the 20- to 30-fold increase of serum
[[beta].sub.2]-microglobulin. Prohepcidin: expression and cell specific
localisation in the liver and its regulation in hereditary
haemochromatosis, chronic renal insufficiency, and renal anaemia. Anal Biochem 2002;301:49-56.
(116.) del Giudice EM, Santoro. finding electric problems in a car can be challenging. It is very difficult to trace one of the hundreds of wires in a vehicle. You need a specialized electric automotive repair shop to find most electric problems in a vehicleN, Amato A, Brienza C, Calabro P,
Wiegerinck ET, et al. On the
other hand, increased hepcidin concentrations may lead to iron
deficiency and blunt the efficacy of iron fortification programs by
decreasing iron absorption (157). HIF-2alpha, but not HIF-1alpha, promotes iron absorption
in mice. Novel urine hepcidin assay by mass spectrometry. Acta Haematol
2009;122:226-9.
Joyce J.C. Hepcidin
agonists could be useful to prevent iron overload attributed to hepcidin
deficiency, such as HH, and especially [beta]-thalassemias and other
iron-loading anemias, and possibly some acquired forms of
non-hemochromatotic iron-overload diseases. J Mol Med 2010;88:477-86.
Recent observations suggest that the erythropoietic signal may
include 1 or more proteins released at sites of active erythropoiesis,
i.e., growth differentiation factor-15 (growth differentiation factor-15
(GDF15) and twisted gastrulation protein homolog-1 (TWSG1). 1) (3). It is likely that additional
erythropoietic factors downregulating hepcidin expression will be
identified.
(11.) Park CH, Valore EV, Waring AJ, Ganz T. Mass
spectrometry-based hepcidin measurements in serum and urine: analytical
aspects and clinical implications. Haematologica 2008;93:1473-9.
[1] Department of Laboratory Medicine, Laboratory of Genetic,
Endocrine and Metabolic Disorders, [2] Hepcidinanalysis.com, Radboud
University Nijmegen Medical Centre, Nijmegen, the Netherlands; [3] Saint
Louis University School of Medicine, St. Intracellular iron stores
communicate with hepcidin via BMPs, particularly BMP-6, in a paracrine or autocrine fashion. Severe iron
deficiency blunts the response of the iron regulatory gene Hamp and
proinflammatory cytokines to lipopolysaccharide. J Clin Invest
2007;117:1926-32.
Hepcidin in acquired forms of nonhemochromatotic iron overload.
Several nonhereditary liver diseases such as excessive alcohol
consumption, nonalcoholic fatty liver disease and nonalcoholic
steatohepatitis are associated with mild hepatic iron overload. Kroot, [1] Harold Tjalsma, [1,2] Robert E. Possibly hepcidin should be
regarded as a marker of response rather than resistance to ESA treatment
in these patients.
(7.) Melino S, Garlando L, Patamia M, Paci M, Petruzzelli R. Blood 2005;106:2196-9.
(177.) Bratescu LO, Barsan L, Munteanu D, Stancu S, Mircescu G. Am J Hematol
2011;86: 107-9.
(200.) Peeling P, Dawson B, Goodman C, Landers G, Wiegerinck ET,
Swinkels DW, Trinder D. Hepcidin as a predictor of response to epoetin therapy in
anemic cancer patients. Relationship of hepcidin with parasitemia and anemia among
patients with uncomplicated Plasmodium falciparum malaria in Ghana. Phlebotomies or erythropoietin injections allow mobilization
of iron stores in a mouse model mimicking intensive care anemia. However, the redox activity of iron can also
cause damage, primarily by the production of reactive oxygen radicals.
As such, iron concentrations must be tightly regulated both at the
cellular and the systemic level. Anemia of chronic disease. BMP6 treatment compensates for the
molecular defect and ameliorates hemochromatosis in Hfe knockout mice.
Gastroenterology 2010;139:1721-9.
For Hodgkin lymphoma we recently demonstrated that increased IL-6
production is associated with induction of hepcidin, which contributes
to the iron-restricted anemia of chronic disease often observed at
Hodgkin lymphoma diagnosis. Mass spectrometry analysis of hepcidin peptides in
experimental mouse models. Patients with most forms of
HH have the inability to appropriately upregulate hepcidin synthesis in
response to increased iron stores. Large and well-designed studies exploiting
harmonized assays are required to more firmly establish the position of
hepcidin in diagnostic medicine. Contribution of
STAT3 and SMAD4 pathways to the regulation of hepcidin by opposing
stimuli. Iron is
necessary for microbial growth, and reductions in plasma iron are
bacteriostatic. Nat Med 2007;13:1096-101.
Several physiologic and pathologic processes regulate the synthesis
of hepcidin (Fig. TLR4-dependent hepcidin expression by myeloid cells in response
to bacterial pathogens. Neither of these
factors, however, appears to be required to mediate the decrease in
hepcidin observed with EPO administration. Blood Cells Mol Dis 2008;40:339-46.
Montosi G, Chen S, et al. Blood 2011;117:997-1004.
(154.) de Mast Q, van Dongen-Lases EC, Swinkels DW, Nieman AE,
Roestenberg M, Druilhe P, et al. Consistent with this iron
loading, low hepcidin concentrations have been found in these patients,
along with other changes in the expression of iron-transport genes
[reviewed in (159)]. We
observed lower serum hepcidin concentrations in premenopausal women than
in postmenopausal women (median 4.1 nmol/L vs 8.5 nmol/L) (109).
Hepcidin concentrations in men were constant over age (median 7.8
nmol/L). Mutations in the gene encoding the cellular iron
exporter ferroportin can also cause HH. J Clin Endocrinol
Metab 2009;94:5102-7.
(219.) Xiao JJ, Krzyzanski W, Wang YM, Li H, Rose MJ, Ma M, et al.
Pharmacokinetics of anti-hepcidin monoclonal antibody Ab 12B9m and
hepcidin in cynomolgus monkeys. Hepcidin
in CKD also has been associated with iron-restricted erythropoiesis, as
reflected by the relation of hepcidin with lower hemoglobin and/or
reticulocyte counts (31, 169, 171). Blood
2009;114:493-4.
(64.) Wrighting DM, Andrews NC. Int J Obes 2009;33:1111-7.
(209.) Corradini E, Schmidt PJ, Meynard D, Garuti C,
HEPCIDIN AGONISTS
(164.) Thomas C, Kobold U, Balan S, Roeddiger R, Thomas L. However, these assays could be used
to measure hepcidin only in a semiquantitative manner.
(82.) Brookes MJ, Sharma NK, Tselepis C, Iqbal TH. Gardenghi et
al. As a result the outcomes of studies to assess the
diagnostic value of hepcidin largely have depended on the definition of
surrogate gold standards. The hepcidin-binding site on ferroportin is
evolutionarily conserved. Altogether, these limitations should be kept in mind
during the interpretation of urine hepcidin data and the decision to
develop dedicated point-of-care devices for urine hepcidin measurements.
(17.) Tessitore N, Girelli D, Campostrini N, Bedogna V, Pietro SG,
Castagna A, et al. In
general, these studies have reported increased hepcidin concentrations
in CKD patients compared with healthy controls (15, 16, 29, 31, 32, 88,
89, 96, 167-169). J Biol Chem 2011;286:4090-7.
(169.) Weiss G, Theurl I, Eder S, Koppelstaetter C, Kurz K,
Sonnweber T, et al. The utility of multivariate analysis
in the study of hepcidin. Hepcidin: from
discovery to differential diagnosis. International Conference on
Harmonisation of Technical Requirements for Registration of
Pharmaceuticals for Human Use: ICH harmonised tripartite guideline text
on validation of analytical procedures. Situations in which demand for
circulating iron is increased (particularly erythropoietic activity)
elicit a decrease in hepatocellular hepcidin synthesis. Resistance to hepcidin is conferred
by hemochromatosis-associated mutations of ferroportin. Hepcidin
expression and iron transport in alveolar macrophages. The excretion of the latter low molecular
weight protein is known to be almost completely governed by glomerular
filtration. Soluble
HJV, which also acts as an antagonist of BMP signaling, decreases
hepcidin baseline expression in mice, mobilizes RE-system (splenic) iron
stores, increases liver iron content and concurrently increases serum
concentrations (208). Erythropoietin administration in humans causes a marked and
prolonged reduction in circulating hepcidin. Whether HIFs directly bind to the
hepcidin promoter is currently controversial. Louis, MO.
(194.) Maes K, Nemeth E, Roodman GD, Huston A, Esteve F, Freytes C,
et al. The introduction of ESAs, such as EPO,
has allowed effective treatment of anemia in patients with CKD. Such pathogens are
common in malaria-endemic regions. In cases in which interference has occurred, assays must be
revalidated for this specific application before definite conclusions on
the efficacy of the therapy can be drawn. This latter observation suggests a role
for hepcidin in modulating acute inflammatory responses to bacterial
infection.
(178.) Ho J, Lucy M, Krokhin O, Hayglass K, Pascoe E, Darroch G, et
al. The prevalence of iron deficiency is
high among athletes. Haematologica
2010;95:505-8.
(93.) Bansal SS, Halket JM, Bomford A, Simpson RJ, Vasavda N, Thein
SL, Hider RC. Iron in arterial plaque: modifiable risk factor
for atherosclerosis. Am J Physiol Gastrointest Liver
Physiol 2006;291:G229-37.
(65.) Verga Falzacappa MV, Vujic SM, Kessler R, Stolte J, Hentze
MW, Muckenthaler MU. Erythropoietin mediates hepcidin expression in hepatocytes
through EPOR signaling and regulation of C/EBPalpha. Macrophage iron, hepcidin, and atherosclerotic
plaque stability. Simple and
sensitive quantification of bioactive peptides in biological matrices
using liquid chromatography/selected reaction monitoring mass
spectrometry coupled with trichloroacetic acid clean-up. It
appears that hepcidin values, like those of other hormones, should be
interpreted in the context of other indices of iron metabolism. High-sensitive radioimmunoassay for
human serum hepcidin. Haematologic data, iron parameters and molecular findings in
two new cases of iron-refractory iron deficiency anaemia. Defects in TfR2 and HFE lead to
decreased hepcidin concentrations via the extracellular signal-regulated
kinases: the mitogen-activated protein kinase (ERK/MAPK) pathwayand/or
the bone morphogenetic protein/mothers against decapentaplegic homolog (Drosophila) (BMP/SMAD) pathway (Fig. PLoS ONE 2011;6: e16762.
(126.) Piperno A, Girelli D, Nemeth E, Trombini P, Bozzini C,
Poggiali E, et al. (87)
Bansal et al. Evaluation of hepcidin isoforms in hemodialysis
patients by a proteomic approach based on SELDI-TOF MS. Further studies in which hepcidin response to iron
supplementation is used as a proxy for the gold standard of iron status
would be informative. Exercise as a mediator of hepcidin activity in
athletes. By
contrast, mutational defects that result in the loss of ferroportin
function cause cellular iron overload due to compromised iron export.
Such patients thus have some phenotypic characteristics which vary from
those of classical HH and have been reported to have high (urinary)
hepcidin concentrations when untreated (127).
We foresee the following potential applications of hepcidin
measurements in patients diagnosed with or suspected for HH: (a)
screening for the presence of HH in patients with increased ferritin
concentrations; (b) prioritization of genes to be investigated (very low
hepcidin concentrations point to juvenile HH forms); (c) prediction of
which C282Y-homozygous patients will be at risk for iron overload; and
(d) monitoring of phlebotomy treatment (123, 133).
(202.) Troadec MB, Laine F, Daniel V, Rochcongar P, Ropert M,
Cabillic F, et al. (43)
(a) UPLC, ultra-high pressure LC; MS/MS, tandem MS; Q,
quadrupole; HBD, hepcidin-binding domain.
Table 2. Recent advances in the understanding of iron overload in
sideroblastic myelodysplastic syndrome. Hepcidin concentrations have not been
consistently compared between races and there are few studies in
children (113-120). Mild increases in serum hepcidin and
interleukin-6 concentrations impair iron incorporation in haemoglobin during an experimental human malaria infection. Some studies showed that hepcidin is an
appropriate marker in the differentiation of ACD and IDA/ACD but not of
IDA and IDA/ACD (75), whereas others have reported that hepcidin allowed
distinguishing IDA from IDA/ACD but not ACD from IDA/ACD (13,164).
Results of another study have suggested that hepcidin concentrations can
serve as an appropriate marker to differentiate between all 3 groups
(165).
(131.) Wijngaarden P, Hoskam J, Koeken A, Boer JMA, Swinkels DW,
Ermens AAM, Cobbaert CM. Rheumatol Int 2010;30:917-23.
[FIGURE 1 OMITTED]
(196.) Zucker SD. Cell Metab 2008;8:146-56.
(74.) Darshan D, Frazer DM, Wilkins SJ, Anderson GJ. Am J Clin
Nutr 2009;90: 1280-7.
INTERACTION BETWEEN HEPCIDIN REGULATORY PATHWAYS
Several components can interfere with the BMP/ SMAD pathway.
Administration of dorsomorphin, a small inhibitor of BMP signaling,
prevented hepcidin induction by iron in mice (212). Blood 2007;110:4096-100.
(136.) Kearney SL, Nemeth E, Neufeld EJ, Thapa D, Ganz T, Weinstein
DA, Cunningham MJ. Anemia in Hodgkin's lymphoma: the role of
interleukin-6 and hepcidin. In these
so-called nonhemochromatotic iron overload diseases, hepcidin
concentrations are increased, but relatively low for the level of iron
overload, suggesting ineffective liver iron sensing. et al. Clin Chim Acta 2010;411:453-5.
(88.) Bansal SS, Abbate V, Bomford A, Halket JM, Macdougall IC,
Thein SL, Hider RC. Med Sci Sports Exerc
2009;41:1138-45.
Liver iron stores and circulating transferrin-bound iron
(Tf-[Fe.sub.2]) each provide distinct signals to influence hepatocyte hepcidin expression (44-46) and are considered separately (Fig. This difficulty is due
to the small and compact structure of hepcidin, which leaves scarce
antigenic epitopes (Fig. Nat Chem Biol 2008;4:33-41.
Human hepcidin is predominantly produced by hepatocytes as a 25
amino acid peptide (2789.4 Da) (1, 2), that is secreted into the
circulation. Hereditary haemochromatosis. Interleukin-6 induces hepcidin
expression through STAT3. Intravenous iron administration was found not to
influence hepcidin concentrations in hemodialysis (HD) patients that
were withheld from iron and ESA therapy for 2 weeks (169), whereas it
increased hepcidin in iron-naive CKD patients (31, 96). Studies in
patients with multiple myeloma suggest that hepcidin is upregulated in
these patients by both IL-6-dependent and IL-6-independent mechanisms
that may play a role in the anemia often observed in these patients. Moreover, the
response of the hepcidin to oral iron might prove to be a useful test to
evaluate iron absorption in iron deficiency.
(173.) Zaritsky J, Young B, Wang HJ, Westerman M, Olbina G, Nemeth
E, et al. Here, we review the major
advances from studies on the structure, kinetics, regulation, and
function of hepcidin and the current state-of-the-art in hepcidin
assays. Diagnosis and
management of hereditary haemochromatosis. Reduction of serum hepcidin by hemodialysis in pediatric and
adult patients. J Nutr 2001;131: 616S-33S.
(179.) Prowle JR, Westerman M, Bellomo R. Recombinant human hepcidin expressed in Escherichia
coli isolates as an iron containing protein. Bone morphogenetic protein signaling by hemojuvelin regulates
hepcidin expression. (96) (Bachem)
Grebenchtchikov et al. Pathophysiology of transfusional iron overload:
contrasting patterns in thalassemia major and sickle cell disease.
Hemoglobin 2009; 33(Suppl 1):S37-45.
Hepcidin-targeted therapies may improve treatment options for
patients suffering from iron disorders. Hepcidin might also contribute indirectly
to host defense by reducing plasma iron concentrations. The molecular basis of ferroportin-linked hemochromatosis.
Proc Natl Acad SciUSA 2005;102:8955-60.
To date, differences in hepcidin concentrations between the sexes
have not been consistently found (12, 29, 85, 96, 97, 107). Proc Natl Acad SciUSA2001;98: 8160-2.
(163.) Andrews NC. Blood
2011;117:e218-25.
. Exp Biol Med 2007; 232:1014-20.
Hepcidin Synthesis and Structure
(189.) Sullivan JL. Association of body iron stores with low
molecular weight iron and oxidant damage of human atherosclerotic
plaques. Repeated intravenous iron
infusions, on the other hand. Polymorphisms and mutations of human TMPRSS6 in iron deficiency
anemia. J Am Soc Nephrol 16,
49A 2005.
(161.) Fleming RE, Sly WS. Involvement of hepcidin in the anemia of multiple myeloma.
Clin Cancer Res 2008;14:3262-7.
(90.) Campostrini N, Castagna A, Zaninotto F, Bedogna V, Tessitore
N, Poli A, et al. (88)
LC-MS/MS Murphy et al. Mice lacking intestinal HIF2[alpha] have decreased expression of
both ferroportin and divalent metal transporter 1, the principal iron
importer at the apical surface of duodenal enterocytes, and thus fail to
induce iron absorption even upon lowering of hepcidin expression (63).
These data suggest that in hypoxic (or iron deficient) conditions,
expression of HIF2[alpha] promotes iron absorption from the intestine
via increased activity of divalent metal transporter 1 and ferroportin.
This result implies that HIF2[alpha]-induced changes in iron transport
can override the effects of the hepcidin-ferroportin regulatory axis.
(224.) Kemna EH, Tjalsma H, Willems HL, Swinkels DW. Iron
delocalisation in the pathogenesis of ma larial anaemia. Alcohol-dependent
downregulation of C/EBP[alpha], probably through radical oxygen species,
might be responsible for a decrease of hepcidin expression and
subsequent (mild) iron overload in heavy drinkers (69, 70).
Previously published online at DOI: 10.1373/clinchem.2009.140053
(40.) De Domenico I, Zhang TY, Koening CL, Branch RW, London N, Lo
E, et al. These
patients demonstrated an exaggerated increase in serum iron
concentrations upon oral iron loading (132). In a recent study among
elderly individuals ([greater than or equal to]65 years old), the
presence of anemia could not be attributed to increased hepcidin
concentrations, because urinary hepcidin concentrations were
significantly lower among participants with inflammation anemia and iron
deficiency compared with nonanemic controls. This dysregulation is caused by
defects in certain genes encoding for positive regulators of hepcidin
(HFE, TfR2, HJV), or, rarely, the hepcidin gene [hepcidin antimicrobial
peptide (HAMP)] itself [reviewed in (123, 124)]. (29)
Koliaraki et al. Reports on the effect
of a defective HFE/TfR2 pathway on hepcidin upregulation by inflammation
are not consistent. Urinary hepcidin in congenital chronic anemias.
Pediatr Blood Cancer 2007;48:57-63.
(115.) de Mast Q, Syafruddin D, Keijmel S, Olde RT, Deky O, Asih
PB, et al. J Leukoc Biol 2007;82:934-45.
Hepcidin Regulation
Although the number of studies on the role of hepcidin in the
anemia of cancer is limited, these studies have contributed to our
insights regarding the mechanisms involved. Haematologica 2010;95:1068-74.
(58.) Nicolas G, Chauvet C, Viatte L, Danan JL, Bigard X, Devaux I,
et al. Anemia of chronic heart failure has
been found to be associated with low hepcidin concentrations, making
(low-grade) inflammation less likely as the sole underlying mechanism
(184, 185).A study on acute cardiac ischemia showed a transient increase
in serum hepcidin-20 concentrations for the majority of patients
studied, whereas hepcidin-25 remained increased 7 days after the
incident. This situation implies
that until harmonization is achieved, reference intervals as well as
clinical decision limits for certain patient populations specific to the
assay methods should be used. Quantitation of hepcidin in human urine by liquid
chromatography-mass spectrometry. The presence of the iron exporter ferroportin at the plasma membrane
of macrophages is enhanced by iron loading and downregulated by
hepcidin. Serum hepcidin and macrophage iron correlate with
MCP-1 release and vascular damage in patients with metabolic syndrome
alterations. World J Gastroenterol 2007;13:4925-30.
Hepcidin in obesity-related diseases. Although the
smaller forms of hepcidin do not elicit a hypoferremic response, it is
currently unknown whether they retain other identified biological
functions of hepcidin-25 (e.g., in host defense or in metal binding) (4,
6, 11, 43).
(113.) Semrin G, Fishman DS, Bousvaros A, Zholudev A, Saunders AC,
Correia CE, et al. to propose that
exercise-induced increases in hemolysis and hepcidin expression may have
2 effects. Surprisingly, these results are not fully
consistent with those found for patients with CKD (see above), but
suggest that baseline hepcidin concentrations may play a potential role
as a predictive marker to identify patients who either are going to
respond adequately to EPO therapy or need to be excluded from anemia
correction with ESA owing to a low chance of responding.
(49.) Silvestri L, Pagani A, Nai A, De D, I, Kaplan J, Camaschella
C. For
instance, it is possible that "normal" concentrations of
hepcidin in iron deficiency anemia (IDA) are inappropriately high, and
perpetuate iron restriction.
(130.) Mayr R, Janecke AR, Schranz M, Griffiths WJ, Vogel W,
Pietrangelo A, Zoller H. Hepcidin serum levels and resistance to recombinant
human erythropoietin therapy in haemodialysis patients. Blood Cells Mol Dis 2002;29:
327-35.
(77.) Constante M, Jiang W, Wang D, Raymond VA, Bilodeau M, Santos
MM. Afebrile Plasmodium falciparum parasitemia decreases
absorption of fortification iron but does not affect systemic iron
utilization: a double stable-isotope study in young Beninese women. Am J Trop Med Hyg 2011;84: 148-51.
(217.) Kawabata H, Tomosugi N, Kanda J, Tanaka Y, Yoshizaki K,
Uchiyama T. Blood 2006;107:328-33.
(20.) Peyssonnaux C, Zinkernagel AS, Datta V, Lauth X, Johnson RS,
Nizet V. Interpretation of urinary hepcidin data is
difficult because urine concentrations may also depend on glomerular
filtration, tubular reabsorption, local production by tubular epithelial
cells (25), and production by interstitial inflammatory cells (108).
These issues make measurement of hepcidin somewhat disadvantageous in
urine compared to serum and imply that for reliable interpretation of
urine hepcidin concentrations as an alternative for serum
concentrations, information on renal hepcidin production and handling is
needed. Curr Opin Crit Care 2003;9:496-502.
(121.) Van Santen S, de Mast Q, Luty AJ, Wiegerinck ET, van der Ven
A, Swinkels DW. HH comprises several
genetic disorders of iron homeostasis characterized by body iron excess.
This results in body iron overload, which can progress to organ injury,
such as liver fibrosis and cirrhosis (122). Hepcidin-25 is a marker of the
response rather than resistance to exogenous erythropoietin in chronic
kidney disease/chronic heart failure patients. Nat Genet 2008;40: 569-71.
(9.) Schranz M, Bakry R, Creus M, Bonn G, Vogel W, Zoller H.
Activation and inactivation of the iron hormone hepcidin: biochemical
characterization of prohepcidin cleavage and sequential degradation to
N-terminally truncated hepcidin isoforms. Blood 2006;107:3727-32.
(52.) Ashby DR, Gale DP, Busbridge M, Murphy KG, Duncan ND, Cairns
TD, et al. Cell Metab 2008;8:502-11.
* Address correspondence to this author at: Department of
Laboratory Medicine, Laboratory of Genetic, Endocrine and Metabolic
Diseases 830, Radboud University Nijmegen Medical Centre, P.O. Box 9101,
6500 HB Nijmegen, the Netherlands. (86)
Li et al. These
findings are in agreement with results of studies demonstrating that
high erythroid demand for iron blunts hepcidin induction by a
concomitant inflammatory response (50, 72-75). In vivo studies in mice have
demonstrated that only full-length 25 amino acid hepcidin induces
significant hypoferremia when injected intraperitoneally (18). J Biol Chem
2001;276:7806-10.
(142.) Cuijpers ML, Raymakers RA, Mackenzie MA, de Witte TJ,
Swinkels DW. As expected, patients with these mutations have a phenotype
similar to classical HH. In addition, Ganz et al.
(29) developed a competitive (c)ELISA for human serum hepcidin. Hemojuvelin
(HJV), a BMP coreceptor (47), is crucial for hepcidin expression because
various hepcidin regulatory pathways converge at this membrane-bound
protein. (92)
HBD assay De Domenico et al. J Pept Res 2005;66:65-71.
(45.) Ramos E, Kautz L, Rodriguez R, Hansen M, Gabayan V, Ginzburg
Y, et al. High-throughput matrix-assisted laser desorption ionization-time-of-flight mass spectrometry method for quantification of
hepcidin in human urine. Hepcidin in human iron disorders: therapeutic
implications. Loss of
matriptase-2 activity results in an inability to reduce hepcidin
synthesis during iron deficiency (49). Ferroportin disease: a systematic meta-analysis
of clinical and molecular findings. Quality control based on
isotopic distributions for high-throughput MALDI-TOF and MALDI-FTICR
serum peptide profiling. A dual-monoclonal sandwich ELISA specific for
hepcidin-25. Induction of erythropoiesis and iron utilization by the HIF
prolyl hydroxylase inhibitor FG-4592 [Abstract]. have been reported to (partially) increase
hemoglobin and mean cell volume (119, 120, 148-151). Blood 2008;111:2392-9.
(78.) van Deuren M, Kroot JJ, Swinkels DW. Haematologica
2010;96:500-6.
(25.) Kulaksiz H, Theilig F, Bachmann S, Gehrke SG, Rost D,
Janetzko A, et al. Another
potential drawback of urine hepcidin measurements is its sensitivity to
oxidation (30) and the relatively high concentration of the smaller
hepcidin isoforms, which cannot be distinguished from hepcidin-25 by
most immunoassays. The STARD initiative and the reporting of studies
of diagnostic accuracy. Serum hepcidin but not prohepcidin may be an effective marker for
anemia of inflammation (AI). These extracellular signaling molecules act on
hepatocellular BMP receptors to activate the intracellular SMAD signaling pathway and increase hepcidin transcription. Annu Rev Pathol 2009;4: 489-515.
(165.) Sasu BJ, Li H, Rose MJ, Arvedson TL, Doellgast G, Molineux
G. Hepcidin antagonists, on the
other hand, might be expected to benefit patients with diseases of
hepcidin excess manifested as iron-restricted anemia and systemic iron
deficiency, such as iron-refractory IDA, ACD (rheumatic diseases,
inflammatory bowel diseases, autoimmune diseases), CKD, multiple myeloma
and other cancers, obesity-related iron deficiency, and cardiovascular
disease.
STRENGTHS AND LIMITATIONS OF QUANTITATIVE PLASMA AND URINE HEPCIDIN
ASSAYS
Table 1. Moreover, well-designed large
clinical studies addressing safety and long-term efficacy are needed to
clarify the risks and benefits of hepcidin-targeted treatments.
(198.) Peeling P, Dawson B, Goodman C, Landers G, Trinder D.
Athletic induced iron deficiency: new insights into the role of
inflammation, cytokines and hormones. Although the physiological relevance of GDF15 and TWSG1 remains
to be defined, these proteins might have therapeutic potential. Biochem J 2010;431:363-71.
(33.) Sumboonnanonda A, Malasit P, Tanphaichitr VS, Ong-ajyooth S,
Sunthornchart S, Pattanakitsakul S. Nat Genet
2004;36:481-5.
(27.) Isoda M, Hanawa H, Watanabe R, Yoshida T, Toba K, Yoshida K,
et al. Rapid Commun Mass Spectrom 2010;24:1251-9.
(120.) Tchou I, Diepold M, Pilotto PA, Swinkels D, Neerman-Arbez M,
Beris P. This stress response can be controlled by the transcription
factor cAMP-response-element-binding-protein-H (67) or by the
stress-inducible transcription factors CCAAT-enhancer-binding protein
(C/EBP[alpha]) and C/EBP-homologous protein (68). Growth differentiation factor 15 in patients with
congenital dyserythropoietic anaemia (CDA) type II. Two to
tango: regulation of Mammalian iron metabolism. Obesity (Silver Spring)
2010;18:1449-56.
Recent studies have demonstrated hepcidin expression by cells other
than hepatocytes, although at much lower levels by comparison. Studies to assess the
role of hepcidin in ACD are complicated by the lack of a gold standard
methodology. These observations raise
the possibility that hepcidin may prove to be a novel determinant for
cardiovascular disease risk.
(59.) Nemeth E, Rivera S, Gabayan V, Keller C, Taudorf S, Pedersen
BK, Ganz T. Through an autocrine interaction with ferroportin, local hepcidin may protect the nearby
cells from iron deficiency, prevent extracellular oxidative stress,
affect inflammatory reponses, and/or deplete extracellular iron pools
that are available for extracellular pathogens (27, 40-42). J Clin Invest
2002;110:1037-44.
(54.) Pak M, Lopez MA, Gabayan V, Ganz T, Rivera S. Biochimie
2009;91:1223-8.
(168.) Zaritsky JJ, Young BY. Posttranslational processing of hepcidin
in human hepatocytes is mediated by the prohormone convertase furin.
Blood Cells Mol Dis 2008;40:132-8.
(152.) Oppenheimer SJ. It exerts its regulatory function
by counteracting the function of ferroportin, the major cellular iron
exporter in the membrane of macrophages, hepatocytes, and the
basolateral site of enterocytes. Blunted hepcidin response to oral iron challenge in
HFE-related hemochromatosis. Accordingly, patients have
increased innate hepcidin concentrations resulting in extremely low
transferrin saturation percentages and ferritin concentrations in the
lower range of the reference interval (118, 119, 120, 148-151).
Therefore, assessment of hepcidin concentrations can serve to exclude or
raise the suspicion for matriptase-2 deficiency in unexplained IDA and
thus help to avoid the unnecessary burden associated with multiple
diagnostic testing and delayed or ineffective treatment.
(21.) Bekri S, Gual P, Anty R, Luciani N, Dahman M, Ramesh B, et
al. Mutations in TMPRSS6 cause iron-refractory iron
deficiency anemia (IRIDA). In addition, the lower hepcidin concentrations observed
in response to hypoxia may be attributed to liver-specific stabilization
of hypoxia-inducible factor (HIF)-1 (60), with downstream effects on the
BMP/ SMAD signaling pathway (61, 62). Moreover, there is a need for harmonization of the various
assays to enable the establishment of world-wide reference intervals and
clinical decision limits. We furthermore summarize human studies of hepcidin in
physiological and pathophysiological states, and discuss the evidence of
the therapeutic potential of modulating hepcidin concentrations. These routes
comprise 4 highly interconnected regulatory pathways (Fig. This observation draws
further attention to the concern that lowering hepcidin concentrations
by phlebotomy in HH patients may exacerbate the underlying
pathophysiology, exacerbating the excess release of iron into the
circulation, with an ensuing vicious circle that leads to the need for
more frequent maintenance phlebotomies in HH patients (125, 126).
In a study among anemic cancer patients receiving ESA therapy,
those with relatively low hepcidin concentrations at baseline showed a
better response (197). Swinkels, NOXXON, Pharma AG,
Berlin, Germany; Pieris AG, Freising-Weihenstephan, Germany.
(134.) Kattamis A, Papassotiriou I, Palaiologou D, Apostolakou F,
Galani A, Ladis V, et al. J Clin Oncol 2010;28:2538-43.
The wide reference intervals may be attributed at least partly to
the increase of hepcidin concentrations in the course of the day (12,
29, 96, 97, 107). Regulation of iron homeostasis by the
hypoxiainducible transcription factors (HIFs). J Clin Invest 2010;120:4466-77.
(56.) Tanno T, Porayette P, Sripichai O, Noh SJ, By rnes C,
Bhupatiraju A, et al. Serum
hepcidin-25 may replace the ferritin index in the Thomas plot in
assessing iron status in auto repair anemic patients. To the best of our knowledge there are 2 reported
studies of hepcidin concentrations in pregnant women, both of which
showed that hepcidin concentrations in anemic pregnant women is lower
than in nonanemic pregnant women, but are not related to cord-blood or
newborn hepcidin or other fetal iron parameters (114, 121).
(149.) Melis MA, Cau M, Congiu R, Sole G, Barella S, Cao A, et al.
A mutation in the TMPRSS6 gene, encoding a transmembrane serine protease
that suppresses hepcidin production, in familial iron deficiency anemia
refractory to oral iron. Second, increased hepcidin
activity postexercise may reduce the absorption of iron from the diet
(203). et al. Potential conflicts of interest:
(223.) Janssen MC, Swinkels DW. Br J Haematol 2010; 149:322-33.
(31.) Ashby DR, Gale DP, Busbridge M, Murphy KG, Duncan ND, Cairns
TD, et al. Modelling of a metal-containing
hepcidin. J Hepatol
2008;49:123-33.
(166.) Swinkels DW, Wetzels JF. Whether binding to these carrier molecules influences the
functional properties of hepcidin is uncertain.
Small and large studies of healthy controls have revealed
considerable interindividual variation in hepcidin concentrations,
resulting in wide reference intervals (12, 29, 96, 97, 107, 109)
2006;55:667-74.
(182.) Tussing-Humphreys LM, Nemeth E, Fantuzzi G, Freels S,
Holterman AX, Galvani C, et al. Hereditary
hemochromatosis: genetic complexity and new diagnostic approaches. AAPS J 2010;12:646-57.
(23.) Merle U, Fein E, Gehrke SG, Stremmel W, Kulaksiz H. Hepcidin-25 induces the internalization and degradation of ferroportin (35-38), resulting in increased
intracellular iron stores, decreased dietary iron absorption, and
decreased circulating iron concentrations (Fig. Kidney Int 2009; 75:976-81.
(187.) Lapenna D, Pierdomenico SD, Ciofani G, Ucchino S, Neri M,
Giamberardino MA, Cuccurullo F. 4). pylori-induced
inflammation does not influence iron status through increased hepcidin
production in childhood (118).
(34.) Wan L, Bellomo R, Di GD, Ronco C. PLoS ONE 2009;4:e6618.
(157.) Cercamondi CI, Egli IM, Ahouandjinou E, Dossa R, Zeder C,
Salami L, et al. J Clin Invest 2009;119:1159-66.
Honoraria: None declared.
The development and validation of hepcidin assays paved the way for
a large number of human studies that considerably increased our
understanding of the physiology and pathophysiology of iron homeostasis
and moreover demonstrated promising applications for hepcidin in
diagnostic medicine (Table 2).
(48.) Finberg KE, Whittlesey RL, Fleming MD, Andrews NC.
Down-regulation of Bmp/Smad signaling by Tmprss6 is required for
maintenance of systemic iron homeostasis. Blood 2009;113: 6225-36.
In a proof-of-principle study, Sasu et al. Serum hepcidin levels are innately low in
HFE-related haemochromatosis but differ between C282Y-homozygotes with
elevated and normal ferritin levels. Clinical stability, time of sampling in relation to iron and ESA
therapy, and iron and EPO dosage and dialysis regimens differ between
studies and are likely to influence results. Serum prohepcidin concentration: no association with iron
absorption in healthy men; and no relationship with iron status in men
carrying HFE mutations, hereditary haemochromatosis patients undergoing
phlebotomy treatment, or pregnant women. Hepcidin, a new iron regulatory peptide. Nat Genet 2006;38:531-9.
Expert Testimony: None declared.
(221.) Klaus S, Langsetmo I, Spong S, Gervasi B, Nichols B, Fourney
P, et al. Blood Cells Mol Dis 2008;40: 347-52.
Consultant or Advisory Role: D.W. Br J Haematol
2009;145:657-64.
(107.) Kroot JJ, Hendriks JC, Laarakkers CM, Klaver SM, Kemna EH,
Tjalsma H, Swinkels DW. A new mouse liverspecific gene, encoding a protein
homologous to human antimicrobial peptide hepcidin, is over-expressed
during iron overload. This effect might be attributable in part to
the effect of hypoxia on EPO expression and thus erythropoietic
activityand/or possibly via a direct interaction with hepatocyte
receptors (51). J Hepatol
2009;50:1219-25.
Administration of erythropoiesis-stimulating agents (ESA) was found
to decrease (hepatocyte) hepcidin production in murine, human, and in
vitro studies (50-53). Patients with cancer often suffer from anemia,
generally in association with other markers of inflammation. Haematologica 2007;92: 857-8.
(186.) Kraml PJ, Klein RL, Huang Y, Nareika A, Lopes-Virella MF.
Iron loading increases cholesterol accumulation and macrophage scavenger
recep tor I expression in THP-1 mononuclear phagocytes. First, any postexercise free iron uptake by the RE
macrophages may be trapped within the scavenger cell owing to the action
of hepcidin on the ferroportin transporters, thereby affecting the
recycling of iron back into the circulation. Although no specific hepcidin
therapies are available, several compounds are under development as
hepcidin agonists or antagonists [reviewed in (204-206)]. Am J
Trop Med Hyg 2007;77:623-6.
The quantification of hepcidin has been found to be complicated by
its tendency to aggregate (79) and to stick to laboratory plastics,
necessitating implementation of robust laboratory procedures.
Furthermore, progress in developing a conventional immunochemical hepcidin assay has been hampered by difficulties in generating specific
antihepcidin antibodies in hosts such as rabbits. However, circadian variation in hepcidin could
be secondary as well, because it might be driven by the influence of
iron intake during the day. The hepatocellular interaction of IL-6
with its receptor activates the janus kinase/signal transducer and
activator of transcription-3 signaling pathway (59,64-66). Blood
2010;115:3616-24.
(153.) de Mast Q, Nadjm B, Reyburn H, Kemna EH, Amos B, Laarakkers
CM, et al. Biochim Biophys Acta 2009;1790:718-23.
(61.) Silvestri L, Pagani A, Camaschella C. Serum hepcidin concentration in chronic
haemodialysis patients: associations and effects of dialysis, iron and
erythropoietin therapy. Blood Cells Mol Dis 2010;45: 238-45.
(170.) van der Putten K, Jie KE, van den Broek D, Kraaijenhagen RJ,
Laarakkers C, Swinkels DW, et al. Blocking HIF
could also be of useful for increasing hepcidin concentrations in
iron-overload diseases.
(97.) Grebenchtchikov N, Geurts-Moespot AJ, Kroot JJ, den Heijer M,
Tjalsma H, Swinkels DW, Sweep FG. Tjalsma, Radboud University Ni jmegen
Medical Centre (among others offers services through
hepcidinanalysis.com); D.W. However, the use of
different assay technologies to assess hepcidin concentrations in
patients with disorders of iron metabolism makes it difficult to
interpret the results of the many reported studies. Mass spectrometry-based proteomic analysis of urine in acute kidney
injury following cardiopulmonary bypass: a nested case-control study. (89)
MALDI-TOF MS Kroot et al. Hepcidin regulates cellular iron efflux by binding to
ferroportin and inducing its internalization. Swinkels, Radboud University Nijmegen Medical Centre (among others offers services through
hepcidinanalysis.com).
(203.) Peeling P. 2) (12-17). Clin Chem 2010;56:1725-32.
Hepcidin Methods
(160.) Weiss G, Goodnough LT. Regulation of hepcidin and iron-overload
disease. Erythroid activity, transfusion iron overload, and
hepcidin levels in patients with myelodysplastic syndrome. An insight into the relationships between
hepcidin, anemia, infections and inflammatory cytokines in pediatric
refugees: a cross-sectional study. vivax
malaria. The iron
regulatory peptide hepcidin is expressed in the heart and regulated by
hypoxia and inflammation. The relevance of these studies is questionable,
because of the fact that prohepcidin concentrations correlate with
neither urinary nor serum hepcidin concentrations, nor do they correlate
with relevant physiological responses (71, 81-83). Elderly people often suffer from anemia. Adv Hematol 2010;2010:750643.
REGULATION BY INFLAMMATION
Hepcidin in infectious and inflammatory diseases. These
include kidney tubule, heart, retina, monocytes, neutrophils, fat cells,
alveolar cells, pancreatic [beta]-cells, and cardiomyocardal cells
(20-27). Expression and localization of hepcidin in macrophages: a
role in host defense against tuberculosis. Crit
Care Med 2008;36:2388-94.
(57.) Chou ST, Weiss MJ. Plos One 2008;3:e4030
(12.) Kemna EH, Tjalsma H, Podust VN, Swinkels DW. Results are expected during 2011
(unpublished data).
(109.) Galesloot TE, Vermeulen SH, Geurts-Moespot AJ, Klaver SM,
Kroot JJ, van Tienoven D, et al. Targeting the hepcidin-ferroportin axis in the
diagnosis and treatment of anemias. Clin Chem 2007;53: 620-8.
(132.) Girelli D, Trombini P, Busti F, Campostrini N, Sandri M,
Pelucchi S, et al. It is possible that binding to [alpha]2-macroglobulin or
other carrier proteins prevents circulating hepcidin from being
freelyfiltered. Serum hepcidin is significantly associated
with iron absorption from food and supplemental sources in healthy young
women. J
Endocrinol 2005;184:361-70.
(41.) Theurl I, Theurl M, Seifert M, Mair S, Nairz M, Rumpold H, et
al. reported that transgenic hepcidin overexpression in
[beta]-thalassemia intermedia mice decreased iron overload, and even
ameliorated ineffective erythropoiesis (207).
Several reports suggest the potential use of hepcidin
concentrations in determining cardiovascular risk. The hypothesis that
erythropoietin (EPO) acts directly on hepatocyte receptors in cell
culture (51) could not be confirmed in animal models for anemia, which
showed that decreased hepcidin expression depends on erythropoiesis and
is not directly mediated by EPO (53, 54).
(44.) Hentze MW, Muckenthaler MU, Galy B, Camaschella C. STAT3 mediates hepatic hepcidin expression and its
inflammatory stimulation. Am J Physiol Lung
Cell Mol Physiol 2006;291:L417-25.
(197.) Ukarma L, Johannes H, Beyer U, Zaug M, Osterwalder B,
Scherhag A. Effect of body mass index reduction
on serum hepcidin levels and iron status in obese children. The
former defect leads to greater than normal ferroportin activity and thus
is often described as a "gain of function" ferroportin
mutation. Kidney Int 2010;78:769-73.
(63.) Mastrogiannaki M, Matak P, Keith B, Simon MC, Vaulont S,
Peyssonnaux C. J Clin Oncol 2011;29:e42.
Hepcidin has been demonstrated to be important in the pathogenesis
of other infectious agents as well. Hepcidin in obese children as a potential mediator
of the association between obesityand iron deficiency. (91)
SELDI-TOF MS Campostrini et al. Virtually all studies on hepcidin in CKD patients
revealed a strong positive relationship between hepcidin and ferritin
concentrations. Some studies report a weak, but
significant, negative correlation between serum hepcidin concentrations
and iron absorption (112, 146, 147). These conditions
include iron deficiency, hypoxia, anemia, and conditions characterized
by increased erythropoietic activity. This finding raises the
possibility that in this population hepcidin-independent mechanisms can
cause hypoferremia and anemia of inflammation, and/or that even
otherwise "normal" hepcidin concentrations are sufficient to
sustain anemia once it is initiated (162).
(101.) Kiernan UA, Tubbs KA, Gruber K, Nedelkov D, Niederkofler EE,
Williams P, Nelson RW. Possibly the consequent increase in hepcidin by
inflammatory signals attenuates iron toxicity than would otherwise be
observed in sickle cell disease patients (141, 143).
(100.) Butterfield AM, Luan P, Witcher DR, Manetta J, Murphy AT,
Wroblewski VJ, Konrad RJ. Hepcidin
expression is also increased byoxidative or endoplasmic reticulum stress. A number of exercise-generated mechanisms may
contribute to this low iron status of athletes, including hemolysis,
hematuria, sweating, and gastrointestinal bleeding (198). Other
groups have also reported reliable hepcidin assays that can be divided
in 3 main methodologies: (a)MS(85-95);(b) immunochemical assays,
comprising cRIA (96, 97), cELISA (13, 29, 98, 99), and a 2-site ELISA
(100); and (c) a ligand-binding assay (43) (Table 1). Perhaps, in such areas, untargeted
iron supplementation among iron-replete children might result in severe
adverse events by increasing the proliferation of latent pathogens
(158).
(205.) Pietrangelo A. Blood
2008;112:5241-4.
It is speculative, but conceivable, that under certain conditions
hepcidin escapes renal tubular reabsorption. These findings of increased
hepcidin concentrations led Peeling et al. Increased serum hepcidin and alterations in blood iron
parameters associated with asymptomatic P. Cumulative effects of consecutive running
sessions on hemolysis, inflammation and hepcidin activity. Moreover, in a previous study we found a relatively high
(pre)analytical variation for urine hepcidin measurements (107). Expression of the peptide hormone hepcidin increases in
cardiomyocytes under myocarditis and myocardial infarction. Hepcidin measurement also may be useful in
anticipating consequences of iron supplementation in infectious and
inflammatory diseases.
Hepcidin in Human Iron Disorders
Iron-depleted HFE C282Y patients have been shown to have very low
serum hepcidin concentrations, reflecting the combined effects of the
HFE mutation and phlebotomy on hepcidin expression (125, 132). J Am Soc Mass Spectrom 2010;21:1515-25.
(53.) Vokurka M, Krijt J, Sulc K, Necas E. Circ J 2010; 74:301-6.
DISORDERS ASSOCIATED WITH HEPCIDIN EXCESS
(39.) Sow FB, Florence WC, Satoskar AR, Schlesinger LS, Zwilling
BS, Lafuse WP. ER stress-inducible factor CHOP affects the expression
of hepcidin by modulating C/EBPalpha activity. Under low iron conditions, membrane-bound HJV is cleaved by
matriptase-2, a transmembrane protease serine 6, encoded bythe
transmembrane protease, serine 6 (TMPRSS6) [6] gene, expressed
predominantly in the liver (48, 49). Plasma hepcidin is a modest predictor of dietary iron
bioavailability in humans, whereas oral iron loading, measured by
stable-isotope appearance curves, increases plasma hepcidin. In a pediatric study, no relationship was found
between Helicobacter pylori infection and hepcidin and between cytokine
and hepcidin concentrations, suggesting that H. Recently,
several (199-201) but not all (202) studies showed increased urinary
hepcidin concentrations after exercise. Tohoku J Exp Med 2009;218:93-8.
(133.) Swinkels DW, Fleming RE Novel observations in hereditary
hemochromatosis: potential implications for clinical strategies.
Haematologica 2011;96:485-8.
(162.) Ferrucci L, Semba RD, Guralnik JM, Ershler WB, Bandinelli S,
Patel KV, et al. Characterization of the transition-metal-binding properties of
hepcidin. The serine protease matriptase-2 (TMPRSS6) inhibits hepcidin
activation by cleaving membrane hemojuvelin. Serum hepcidin-20 is elevated during the acute phase of myocardial
infarction. In anemia of multiple myeloma, hepcidin is induced by increased
bone morphogenetic protein 2. Immunochemical and
mass-spectrometry-based serum hepcidin assays for iron metabolism
disorders. In HD patients
on ESA, hepcidin did not predict which patients increase their
hemoblobin after iron loading (17). Pathways underlying iron accumulation in human nonalcoholic fatty
liver disease. Detection of serum hepcidin in renal failure and
inflammation by using ProteinChip System. Distinct requirements for Hfe in basal and induced hepcidin levels
in iron overload and inflammation. Hepatology 2011;53:1333-41.
Hepcidin in hereditary hemochromatosis (HH). Assessment of urinary concentrations of hepcidin provides
novel insight into disturbances in iron homeostasis during malarial
infection. Iron regulatory hormone hepcidin decreases in chronic
heart failure patients with anemia. These results suggest that
quantification of serum hepcidin concentrations could be a predictor for
the therapeutic effect of oral iron administration. We recently
assessed serum hepcidin reference intervals stratified by age and sex
stratified in a reference set selected from a large, well-phenotyped
sample of the general population of the Dutch city of Nijmegen (109). Gastroenterology 2007;132:294-300.
(35.) Nemeth E, Tuttle MS, Powelson J, Vaughn MB, Donovan A, Ward
DM. In small
studies in humans the fractional excretion of hepcidin has been
calculated to be as low as 0%-5% (29, 30), either because it is
reabsorbed, similarly to other small peptides, or because it is not
freely filtered. Fax +31-24-3668754; e-mail
d.swinkels@labgk.umcn.nl.
(218.) Poli M, Girelli D, Campostrini N, Maccarinelli F, Finazzi D,
Luscieti S, et al. At the same time it
should be noted that the relevance of measuring hepcidin-25 instead of
total hepcidin for clinical decision-making has not been systematically
investigated. Currently available hepcidin methods.
MS Reference
HPLC/UPLC (a) MS/MS Kobold et al. Conversely, the increased hepcidin
concentrations seen with inflammation might increase the virulence of
bacteria that depend on macrophage iron for their proliferation within
these cells (e.g., Salmonella and Mycobacteria spp.). Diseased red blood cells topple iron
balance. Serum hepcidin: reference ranges and
biochemical correlates in the general population. These hepcidin peptides form a hairpin structure, with 4
intramolecular disulfide bridges (Fig. Accurate determination of hepcidin concentrations in serum and
urine will improve our understanding of iron metabolism disorders and
may provide a useful tool in the differential diagnosis and clinical
management of such diseases.
At present, there is no single laboratory test that can
definitively distinguish ACD from IDA (160, 163). In sickle
cell disease, patients demonstrate the additional confounding factor of
inflammation. Therefore, the diagnostic
toolbox for hepcidin peptide measurements in animal models should be
improved and extended (75, 219, 222). Development of reference methods and
reference materials. N Engl J
Med 2005;352:1011-23.
(185.) Divakaran V, Mehta S, Yao D, Hassan S, Simpson S, Wiegerinck
E, et al. Role of alcohol in the regulation of iron
metabolism. Blood 2008;112:4292-7.
(183.) Amato A, Santoro N, Calabro P, Grandone A, Swinkels DW,
Perrone L, Miraglia Del Giudice E. HIF antagonists
are used in cancer to inhibit tumor angiogenesis (210). J Hepatol 2010;53: 941-9.
(106.) Forest JC, Burtis CA. This lack of reabsorption
may play a role in several disorders of iron metabolism that are
associated with tubular dysfunction and increased concentrations ofurine
hepcidin, such as inflammation, iron overload, and malaria (33, 34).
Possible local tubular production of hepcidin must also be taken into
account in the interpretation of urine as a mirror of serum hepcidin
concentrations in such studies (25) as well as possible defective
tubular reabsorption of hepcidin. ER stress controls iron metabolism through induction
of hepcidin. Nat Med 2007;13:1020-1.
Preclinical and clinical studies have also shown that hepcidin
antagonists such as hepcidin antibodies, BMP antagonists, cytokine
receptor antibodies, and HIF stabilizers can decrease hepcidin
expression and reverse iron abnormalities (208, 211-218).
(141.) Kroot JJ, Laarakkers CM, Kemna EH, Biemond BJ, Swinkels DW.
Regulation of serum hepcidin levels in sickle cell disease.
Haematologica 2009;94:885-7.
(26.) Gnana-Prakasam JP, Martin PM, Mysona BA, Roon P, Smith SB,
Ganapathy V. Humanized antiinterleukin-6 receptor antibody treatment
of multicentric Castleman disease. Biometals 2006;19: 527-33.
[4] Nonstandard abbreviations: AMI, acute myocardial infarction;
ACD, anemia of chronic disease; CKD, chronic kidney disease; RE,
reticuloendothelial; Tf-[Fe.sub.2], transferrin bound iron; TfR,
transferrin receptor; HFE, hemochromatosis iron protein; ERK/MAPK,
extracellular signal-regulated kinases/mitogen-activated protein kinase;
BMP/SMAD, bone morphogenetic protein/mothers against decapentaplegic
homolog (Drosophila); HJV, hemojuvelin; ESA, erythropoiesis-stimulating
agent; EPO, erythropoietin; GDF15, growth differentiation factor-15;
TWSG1, twisted gastrulation protein homolog-1; HIF, hypoxia inducible
factor; DMT, divalent metal transporter; IL, interleukin; C/EBP,
CCAAT-enhancer-binding protein; c, competitive; MS, mass spectrometry;
IDA, iron deficiency anemia; HH, hereditary hemochromatosis; HD,
hemodialysis.
(204.) Nemeth E. Inhibitors of the key initiators of the
cellular hypoxic response, such as prolyl hydroxylases, prevent
inactivation and degradation of HIF and as such maybe effective hepcidin
suppressors and restore natural iron regulation in anemia (220, 221).
In several early studies a commercial serum-based immunoassay was
used that measures the hepcidin precursor prohepcidin rather than the
bioactive peptide (80). The peptide hormone hepcidin interacts with the cellular
iron exporter ferroportin and thus is now recognized as the key
regulator of systemic iron homeostasis. Genes
that are regulated through E-boxes, including the clock genes period
homolog 1 (Drosophila) (PER1), timeless homolog (Drosophila) (TIMELESS),
and clock homolog (mouse) (CLOCK), tend to be under circadian rhythmic
transcriptional control. Daily regulation of serum and urinary hepcidin is not
influenced by submaximal cycling exercise in humans with normal iron
metabolism. Cell 2010;142:24-38.
Received May 10, 2011; accepted July 20, 2011.
(70.) Harrison-Findik DD. It has been
hypothesized that increased hepcidin concentrations may enhance
cardiovascular risk by increasing intracellular macrophage iron
concentrations and by increasing their atherogenic potential (186-189).
Furthermore, recent studies showed increased hepcidin production in
patients with (low-grade) inflammation, obesity, and nonalcoholic fatty
liver disease, which are traditionally associated with cardiovascular
disease (21, 144, 190, 191). Blood 2005; 106:2627-32.
(137.) Origa R, Galanello R, Ganz T, Giagu N, Maccioni L, Faa G,
Nemeth E.
(124.) Lee PL, Beutler E. Therefore, a
second Round Robin for plasma hepcidin was initiated to explore
word-wide hepcidin harmonization by exchanging synthetic materials for
assay harmonization and native samples. This latter variation is not surprising given
the absence of a reference method (106) and a validated commutable calibrator or other material for assay harmonization. However, there are 2 classes of
ferroportin mutations with different phenotypic consequences: loss of
hepcidin regulation and loss of ferroportin function (36, 128-130). Eur J Appl Physiol 2005;95:569-71.
(67.) Vecchi C, Montosi G, Zhang K, Lamberti I, Duncan SA, Kaufman
RJ, Pietrangelo A. High-throughput protein characterization using
mass spectrometric immunoassay. The first assays to
measure bioactive hepcidin-25 were an immunodot assay (59), SELDI-TOF
mass spectrometry (MS) (12, 15, 84). Blood Cells Mol Dis
2005;35:177-81.
(16.) Peters HP, Laarakkers CM, Swinkels DW, Wetzels JF. Determinants of hepcidin in patients on maintenance
hemodialysis: role of inflammation. Urinary hepcidin: an
inverse biomarker of acute kidney injury after cardiopulmonary bypass?
Curr Opin Crit Care [Epub ahead of print 2010 Aug 21].
Serum hepcidin concentrations appear to be determined by the
relative strengths of the individual regulators. In conclusion, hepcidin is a
promising diagnostic tool but efforts must be undertaken to assess the
relevance of specifically measuring hepcidin-25, to harmonize assay
outcomes throughout the world, to define clinical decision limits, and
to make assays available to clinical laboratories before hepcidin assays
can be fully included in clinical practice.
Concluding Remarks
(215.) Hashizume M, Uchiyama Y, Horai N, Tomosugi N, Mihara M.
Tocilizumab, a humanized antiinterleukin-6 receptor antibody, improved
anemia in monkey arthritis by suppressing IL-6-induced hepcidin
production. Plasma hepcidin levels are elevated but responsive to
erythropoietin therapy in renal disease. PLoS ONE 2008;3: e2706.
(60.) Peyssonnaux C, Zinkernagel AS, Schuepbach RA, Rankin E,
Vaulont S, Haase VH, et al. falciparum and P. Clearly, future large and
well-designed studies are needed to improve our understanding of this
hepcidin regulatory network in various disorders of iron metabolism.
(118.) Cherian S, Forbes DA, Cook AG, Sanfilippo FM, Kemna EH,
Swinkels DW, Burgner DP. Decreased serum hepcidin and improved
functional iron status 6 months after restrictive bariatric surgery.
Obesity 2010;18:2010-6.
Author Contributions: All authors confirmed they have contributed
to the intellectual content of this paper and have met the following 3
requirements: (a) significant contributions to the conception and
design, acquisition of data, or analysis and interpretation of data; (b)
drafting or revising the article for intellectual content; and (c) final
approval of the published article.
Hepcidin in sports medicine. Time-course analysis of
serum hepcidin, iron and cytokines in a C282Y homozygous patient with
Schnitzler's syndrome treated with IL-1 receptor antagonist.
Haematologica 2009;94:1297-300.
(72.) Lasocki S, Millot S, Andrieu V, Letteron P, Pilard N, Muzeau
F, et al. Natural and synthetic STAT3 inhibitors reduce
hepcidin expres sion in differentiated mouse hepatocytes expressing the
active phosphorylated STAT3 form. J Hepatol 2008;48: 801-10.
(96.) Busbridge M, Griffiths C, Ashby D, Gale D, Jayantha A,
Sanwaiya A, Chapman RS. J Clin Invest 2007;117:1933-9.
(1.) Krause A, Neitz S, Magert HJ, Schulz A, Forssmann WG,
Schulz-Knappe P, Adermann K. The low hepcidin state
relative to ferritin in these patients (125-127) leads to increased
intestinal iron absorption and body iron overload. This cleavage bymatriptase-2
weakens the BMP signaling.
(199.) Roecker L, Meier-Buttermilch R, Brechtel L, Nemeth E, Ganz
T. Nephrol Dial Transplant 2010;25:3996-4002.
https://www.thefreelibrary.com/Hepcidininhumanirondisorders:diagnosticimplications.-a0324761278
MS assays require relatively expensive equipment, but they have the
advantage of distinguishing between hepcidin-25, -22, and -20 (13).
ELISA assays will measure total hepcidin concentrations, with (depending
on the specificity of the antibody) different contributions from each of
these 3 isoforms. (99)
c-RIA Bushbridge et al. Immunoassays have the potential for more widespread use in
clinical laboratories. N Engl J Med 2009;361:1904-6.
Hepcidin in iron-loading anemias. For example, the
accumulation of hepcidin-22 and -20 isoforms may raise questions
regarding the interpretation that measured hepicidin concentrations
reflected bioactive hepcidin-25 in studies in which certain immunoassays
were used. Am J Nephrol 2010;31: 534-40.
(81.) Kemna E, Pickkers P, Nemeth E, van der Hoeven H, Swinkels D.
Time-course analysis of hepcidin, serum iron, and plasma cytokine levels
in humans injected with LPS. et al. Under
physiological conditions hepcidin-20 and hepcidin-22 are present in the
urine, but not, or at very low concentrations, in the serum (11-13).
Interestingly, these smaller hepcidin isoforms occur only in serum of
patients with diseases that are associated with increased concentrations
of hepcidin-25, such as acute myocardial infarction (AMI), [4] sepsis,
anemia of chronic disease (ACD), metabolic syndrome, and chronic kidney
disease (CKD) (Fig. Blood 2007;110:1048-54.
(127.) Papanikolaou G, Tzilianos M, Christakis JI, Bogdanos D,
Tsimirika K, MacFarlane J, et al. However,
the optimal target concentration of hemoglobin is debated, and many
patients become ESA resistant. Arterioscler Thromb Vasc Biol 2011;31:683-90.
Effect of iron administration on hepcidin concentrations. Also, heparin and heparin derivatives have
recently been shown to inhibit hepcidin expression in vitro and in vivo
by interfering with BMP signaling (218).
(29.) Ganz T, Olbina G, Girelli D, Nemeth E, Westerman M.
Immunoassay for human serum hepcidin. (13)
Swinkels et al. (30)
Anderson et al. Blood Cells Mol Dis
2009;43:169-79.
(28.) Peslova G, Petrak J, Kuzelova K, Hrdy I, Halada P, Kuchel PW,
et al. J Biol Chem 2002;277:37597-603.
(8.) Tselepis C, Ford SJ, McKie AT, Vogel W, Zoller H, Simpson RJ,
et al. Swinkels [1,2] *
Since the discovery of hepcidin 10 years ago, multiple studies have
contributed insights into the regulation of hepcidin and its functional
properties. Serum
hepcidin-25 levels in patients with chronic kidney disease are
independent of glomerular filtration rate. Expert Opin Ther Targets 2006;10:267-80.
In addition to its potential as a marker of iron metabolism in
patients with CKD, combined urinary and serum hepcidin concentrations
may serve as a marker for renal disease itself. Liver iron concentrations and urinary hepcidin in
beta-thalassemia. STAT3 is required for IL-6-gp130-dependent
activation of hepcidin in vivo. Training surface and intensity: inflammation,
hemolysis, and hepcidin expression. Br J Haematol 2009; 146:317-25.
In patients with heritable forms of anemia, information on hepcidin
concentrations may be valuable for identifying the most severely
affected patients and predicting and monitoring parenchymal iron
overload.
(150.) Hartman KR, Barker JA Microcytic anemia with iron
malabsorption: an inherited disorder of iron metabolism. Blood
2006;108:4237-45.
(98.) Koliaraki V, Marinou M, Vassilakopoulos TP, Vavourakis E,
Tsochatzis E, Pangalis GA, et al. The swinging pendulum of the anemia of cancer:
erythropoietin trumps hepcidin. Anal Biochem 2008;384:245-53.
(50.) Nicolas G, Viatte L, Bennoun M, Beaumont C, Kahn A, Vaulont
S. To allow proper interpretation of the effect of the
erythropoietic drive on hepcidin production, EPO and hepcidin
concentrations should be assessed simultaneously in selected patients
with anemia of CKD.
(122.) van Bokhoven MA, van Deursen CT, Swinkels DW. Hepcidin mediates transcriptional changes that modulate acute
cytokine-induced inflammatory responses in mice. Eur J Haematol
2009;83:595-602.
(18.) Rivera S, Nemeth E, Gabayan V, Lopez MA, Farshidi D, Ganz T.
Synthetic hepcidin causes rapid dose-dependent hypoferremia and is
concentrated in ferroportin-containing organs. Several
studies have addressed the relationship between iron absorption and
hepcidin concentrations. The
N-terminus of hepcidin is essential for its interaction with
ferroportin: structure-function study. Furin-mediated release
of soluble hemojuvelin: a new link between hypoxia and iron homeostasis.
Blood 2008;111:924-31.
Stock Ownership: None declared.
(79.) Hunter HN, Fulton DB, Ganz T, Vogel HJ. Measurement of serum hepcidin may prove to be useful as a
marker of iron dysregulation in these forms of iron overload.
(211.) Sasu BJ, Cooke KS, Arvedson TL, Plewa C, Ellison AR, Sheng J, et al. (13) (Bachem)
Ganz et al. Hepcidin-a potential novel biomarker for iron status in
chronic kidney disease. 4).
Circulating transferrin appears to be sensed via a hepatocellular
complex, which includes transferrin receptor-1 (TfR1), TfR2, and
hemochromatosis iron protein (HFE). For instance, studies
suggest that smaller increases in urinary hepcidin, relative to serum
hepcidin, maybe associated with a greater risk of acute kidney injury
after coronary artery bypass graft surgery in patients with stable renal
function (178, 179).Ina study on urine biomarkers in patients with lupus
nephritis, urinary concentrations of hepcidin, possibly secreted by
interstitial inflammatory cells, were identified as markers of renal
lupus nephritis flare (108).
(19.) Nemeth E, Preza GC, Jung CL, Kaplan J, Waring AJ, Ganz T. Biochem J 2008;413:553-7.
(51.) Pinto JP, Ribeiro S, Pontes H, Thowfeequ S, Tosh D, Carvalho
F, Porto G. In an attempt to
delineate relative strengths of these regulators in patients with iron
metabolism disorders, we constructed an algorithm to predict relative
hepcidin concentrations based on certain serum parameters (C-reactive
protein, Tf saturation, and soluble TfR) that reflect inflammation,
serum iron, and erythropoietic regulatory pathways (71). Blood 2007;109: 353-8.
(37.) Delaby C, Pilard N, Goncalves AS, Beaumont C, Canonne-Hergaux
F. Intra-individual
variability in serum hepcidin precludes its use as a marker of iron
status in hemodialysis patients. Blood 2009;113:3593-9.
FIRST-GENERATION (SEMIQUANTITATIVE) HEPCIDIN ASSAYS
(105.) Kroot JJ, Kemna EH, Bansal SS, Busbridge M, Campostrini N,
Girelli D, et al. Rapid Commun
Mass Spectrom 2007;21:4033-8.
(89.) Li H, Rose MJ, Tran L, Zhang J, Miranda LP, James CA, Sasu
BJ. SELDI-TOF-MS determination of hepcidin in clinical samples
using stable isotope labelled hepcidin as an internal standard. Clin J Am Soc Nephrol
2009;4:1331-7.
Circulating hepcidin was recently found to be bound to
[[alpha].sub.2]-macroglobulin with relatively high affinity and to
albumin with relatively low affinity. Haematologica 2008;93:90-7.
(176.) Kato A, Tsuji T, Luo J, Sakao Y, Yasuda H, Hishida A.
Association of prohepcidin and hepcidin-25 with erythropoietin response
and ferritin in hemodialysis patients Am J Nephrol 2008;28:115-21.
(22.) Nguyen NB, Callaghan KD, Ghio AJ, Haile DJ, Yang F. In healthy human volunteers hepcidin in urine
and serum increased upon oral iron dosing, although nonresponders were
reported (29, 59, 112, 145-147). Clin Chem 2009;55:1354-60.
(207.) Gardenghi S, Ramos P, Marongiu MF, Melchiori L, Breda L, Guy
E, et al. Iron homeostasis in mother and child during placental
malaria infection. (100)
Hepcidin binding
Q-TOF LC-MS Crockett et al. Development of a novel immunoassay for the iron
regulatory peptide hepcidin. The effects of erythropoetic activity and iron
burden on hepcidin expression in patients with thalassemia major.
Haematologica 2006;91:809-12.
The activation of the hepcidin regulatory pathways described above
are all dependent on interactions of circulating or autocrine factors
with hepatocyte membrane sensors to control the hepatic production of
hepcidin for proper maintenance of systemic iron homeostasis [reviewed
in (44)]. Trans R Soc
Trop Med Hyg 2010; 104:175-84.
[FIGURE 2 OMITTED]
Hepcidin Kinetics
(193.) Sharma S, Nemeth E, Chen YH, Goodnough J, Huston A, Roodman
GD, et al. Harmonization of the methodologies, by
using reliable calibrators or other materials for harmonization, will
enable translational scientists as well as physicians in clinical
practice around the world to collectively define criteria for the use of
hepcidin assays in diagnosis, staging, monitoring, and assessing
treatment indications of iron disorders.
(76.) Roy CN, Custodio AO, de Graaf J, Schneider S, Akpan I,
Montross LK, et al. Blood 2010;115: 3817-26.
(68.) Oliveira SJ, Pinto JP, Picarote G, Costa VM, Carvalho F,
Rangel M, et al. A crucial element in the maintenance of
systemic iron homeostasis is effective communication between cells that
absorb iron from the diet (duodenal enterocytes), use iron (mainly
erythroid precursors), and store iron (hepatocytes and tissue
macrophages). Regulation of type II transmembrane serine proteinase TMPRSS6
by hypoxia-inducible factors: new link between hypoxia signalling and
iron homeostasis. J Clin Invest
2004;113:1271-6.
Hepcidin-Modulating Agents
(13.) Kroot JJC, Laarakkers CM, Geurts-Moespot AJ, Grebenchtchikov
N, Pickkers P, van Ede AE, et al. Hepcidin in iron overload disorders.
Blood 2005; 105:4103-5.
Hepcidin in renal diseases. Although in vitro
studies suggest bacteriocidal effects of hepcidin, these effects would
require concentrations higher than those observed in the circulation.
Such concentrations may be achieved locally, for instance in phagosomes
of infected macrophages (39). Erythropoiesis requires considerable amounts of
iron, so suppression of hepatic hepcidin synthesis by erythropoietic
signals is of great physiological importance. Kidney Int 2009;76:912-3.
(148.) Finberg KE, Heeney MM, Campagna DR, Aydinok Y, Pearson HA,
Hartman KR, et al. These differences
in level assignment hinder the comparability of data collected by use of
the various methods and preclude the definition of universal reference
intervals and cutoff values for clinical decision making. Am J Clin Nutr
2009;89:1088-91.
(145.) Lin L, Valore EV, Nemeth E, Goodnough JB, Gabayan V, Ganz T.
Iron transferrin regulates hepcidin synthesis in primary hepatocyte
culture through hemojuvelin and BMP2/4. However, there are
indirect mechanisms by which HIFs may regulate hepcidin expression.
Increased HIF activity is associated with increased matriptase-mediated
cleavage hemojuvelin and thus decreased hepcidin expression (62).
Moreover, the systemic iron regulation by the hepcidin-ferroportin axis
acts in harmony with the enterocyte cellular iron homeostasis control
system. Hepcidin as a therapeutic tool to limit iron overload and
improve anemia in beta-thalassemic mice. Endocrinology 2007;148: 2663-8.
Hepcidin in cancer. Science 2004;306: 2090-3.
(139.) Malcovati L, Porta MGD, Laarakkers CM, Galli A, Albertini R,
Maffioli M, et al. Blood 2007; 110:2182-9.
(146.) Young MF, Glahn RP, riza-Nieto M, Inglis J, Olbina G,
Westerman M, O'Brien KO. However, this concern might be overcome by exploiting
antibodies that are hepcidin-25 specific (100). These findings again suggest that
the erythroid demand for iron might be a more powerful regulator of
hepcidin expression than inflammatory- or iron-induced hepcidin
formation. Eur J Clin Invest 2009;39: 883-90.
Interestingly, hepcidin also was evaluated as a predictor of ESA
response in several relatively small studies in humans. Pediatr Nephrol 1998;12:280-3.
(69.) Bridle K, Cheung TK, Murphy T, Walters M, Anderson G,
Crawford DG, Fletcher LM. Science 2009;325:877-80.
(55.) Tanno T, Bhanu NV, Oneal PA, Goh SH, Staker P, Lee YT, et al.
High levels of GDF15 in thalassemia suppress expression of the iron
regulatory protein hepcidin. A
novel TMPRSS6 mutation that prevents protease auto-activation causes
IRIDA. Hepcidin
concentrations in untreated patients with rare juvenile forms of HH tend
to be very low (127). Proinflammatory state, hepcidin, and anemia in older
persons. The pathogenesis of septic
acute renal failure. Plasma hepcidin concentrations significantly predict interindividual
variation in iron absorption in healthy men. Hepcidin biology and therapeutic applications.
Expert Rev Hematol 2010;3:153-5.
REGULATION BY IRON STATUS
REGULATION BY HYPOXIA
(102.) Nicolardi S, Palmblad M, Dalebout H, Bladergroen M,
Tollenaar RA, Deelder AM, van der Burgt YE. HFE mutations modulate the effect of iron on serum
hepcidin-25 in chronic hemodialysis patients. Development of a method for the sensitive and quantitative
determination of hepcidin in human serum using LC-MS/MS. Clin Chem 2010;56:1570-9.
(201.) Peeling P, Dawson B, Goodman C, Landers G, Wiegerinck ET,
Swinkels DW, Trinder D. J Infect Dis 2009;199:253-62.
Small hepcidin peptides have been shown to act as agonists in mice
in vivo on the basis of their amino-terminal domain (206). 3).
(172.) Kuragano T, Shimonaka Y, Kida A, Furuta M, Nanami M, Otaki
Y, et al. Elevated growth differentiation factor 15 expression
in patients with congenital dyserythropoietic anemia type I. Blood
2005;106: 3268-70.
REGULATION BY ERYTHROPOIETIC SIGNALS
(6.) Gerardi G, Biasiotto G, Santambrogio P, Zanella I, Ingrassia
R, Corrado M, et al. The
consequences of ineffective erythropoiesis on hepcidin expression thus
appear to trump the consequences of excessive iron stores. The gene encoding the iron regulatory peptide hepcidin is
regulated by anemia, hypoxia, and inflammation. Notably, monitoring of the bioactive serum hepcidin
during treatment by these hepcidin antagonists appears to be complicated
by the interference of the compounds in the assays (219).
(123.) Swinkels DW, Janssen MC, Bergmans J, Marx JJ. Hepcidin might thus be a mediator of the high incidence of iron
deficiency among athletes.
(85.) Murphy AT, Witcher DR, Luan P, Wroblewski VJ. On the basis of some
studies, investigators have reported that hepcidin binds divalent metals
([Cu.sup.2+], [Fe.sup.2+], [Zn.sup.2+], and [Ni.sup.2+]), but these
findings are inconsistent, e.g., some studies have suggested the
presence of iron in the core of the peptide in a tetrahedral sulfur
coordination (4-6), whereas others provide evidence for an
amino-terminal Cu(2+)-Ni(2+)-binding (ATCUN) motif (7, 8). Subsequent amino-terminal processing of the 25 amino acid
form can result in the appearance of 2 smaller hepcidin forms of 22 and
20 amino acids. Overweight children
have higher circulating hepcidin concentrations and lower iron status
but have dietary iron intakes and bioavailability comparable with normal
weight children. (90)
Altamura et al. A
metal-binding site is present in the amino terminal region of the
bioactive iron regulator hepcidin-25. Hepcidin: a new tool in the
management of anaemia in patients with chronic kidney disease? Nephrol
Dial Transplant 2008;23:2450-3.
(114.) Rehu M, Punnonen K, Ostland V, Heinonen S, Westerman M,
Pulkki K, Sankilampi U. Serum and liver iron differently regulate the bone
morphogenetic protein 6 (BMP6)-SMAD signaling pathway in mice.
Hepatology 2011;54:273-84.
(36.) De Domenico I, Ward DM, Nemeth E, Vaughn MB, Musci G, Ganz T,
Kaplan J. A time course of hepcidin response to iron challenge
in patients with HFE and TfR2 haemochromatosis. Nephrol Dial Transplant
2010;25:848-53.
(95.) Ward DG, Roberts K, Stonelake P, Goon P, Zampronio CG, Martin
A, et al. Blood 2010;116: 3635-44.
(83.) Roe MA, Spinks C, Heath AL, Harvey LJ, Foxall R, Wimperis J,
et al. Hepcidin, the iron watcher. Other studies have shown
that increased and/or ineffective erythropoiesis blunts the induction of
hepcidin by increased body iron stores (52, 73). As mentioned earlier, several
investigators have reported a decrease in hepcidin concentrations after
EPO administration (31, 50, 169, 170). (95)
Immunochemical
c-ELISA Kroot et al. Am J Hematol
1996;51:269-75.
(175.) Ford BA, Eby CS, Scott MG, Coyne DW. Am J Clin Nutr 2008;87:1374-83.
Hepcidin clearance is assumed to occur via cellular codegradation
with ferroportin at its sites of action, and via excretion by the
kidneys. Free Radic Biol Med 2007;42:492-8.
Although hepcidin is a promising companion diagnostic for ESA
therapy, patients with renal insufficiency are a rather complex
population in which consistent results have been difficult to obtain
(175). (85)
Murao et al. Clin
Chem 2006;52:950-68.
(156.) Nweneka CV, Doherty CP, Cox S, Prentice A. Because of its low molecular weight and small radius, unbound hepcidin is likely to freely pass into the glomerular filtrate. Metabolism
2005;54:453-9.
(159.) Drakesmith H, Prentice A. Cis and trans regulation of
hepcidin expression by upstream stimulatory factor. Most promising applications of serum
hepcidin in diagnostic medicine.
Disease condition Expected hepcidin
concentrations (a)
Classical Low, maybe compensated
hereditary by iron overload over
hemochromatosis time
Iron-loading Low, maybe compensated
anemias by transfusional iron
overload over time
Acquired forms of Miscellaneous
iron overload
Iron-refractory Inappropriately high
iron deficiency
anemia
Inflammation and High
infection
Chronic kidney High, decreases upon
diseases EPO treatment
Acute kidney Low (urine)
injury
Treatment with Depends on the disorder
hepcidin
antagonists and
agonists
Disease condition Potential added value
of hepcidin diagnostics
Classical Screen for the presence
hereditary of hemochromatosis
hemochromatosis
Predict which homozygotes
will be at risk for iron
overload
Determine the phlebotomy
interval
Prioritize genes to be
investigated
Iron-loading Identify the most
anemias severely affected
patients
Predict and monitor
(parenchymal) iron
overload
Acquired forms of A marker of iron
iron overload dysregulation
Iron-refractory Screen for primary defect
iron deficiency in hepcidin regulation
anemia
Inflammation and Differentiate ACD (b) and
infection IDA
Guide iron supplementation
therapy
Chronic kidney Predict EPO response
diseases
Guide treatment with EPO,
intravenous iron
Acute kidney Diagnose acute kidney
injury injury
Treatment with Monitor and assess
hepcidin indications
antagonists and
agonists
(a) In serum, unless stated otherwise.
(b) ACD, anemia of chronic disease; IDA, iron
deficiency anemia; EPO, erythropoietin.
(213.) Fatih N, Camberlein E, Island ML, Corlu A, Abgueguen E,
Detivaud L, et al. Int J Lab Hematol
2010;33:187-93.
(71.) Kemna EH, Kartikasari AE, van Tits LJ, Pickkers P, Tjalsma H,
Swinkels DW. Hepcidin, the hormone of iron metabolism, is bound specifically
to alpha-2-macroglobulin in blood. if you are handy you can probably replace the battery and or alternator in your car. The problem is that the problem with your vehicle might not be caused by the battery or the alternator! It might be a short in a wire, a bad ground or just a sticky relay that causes the battery to drain or the alternator to not charge the battery. That is why there are professional auto repair shops! http://www.ikev.org/haber/
stabilite/cd/08%201.7%20ICH%20Q2A%20for %20CD.pdf (Accessed June 2011).
REFERENCE INTERVALS FOR SERUM HEPCIDIN
(92.) Crockett DK, Kushnir MM, Phillips JD, Rockwood AL.
Time-of-flight mass spectrometry analysis of the ferroportin-hepcidin
binding domain complex for accurate mass confirmation of bioactive
hepcidin 25. Anal Biochem 2009;389:124-9.
Interpretation of hepcidin test results might be influenced by
whether the various assays are detecting freely circulating hepcidin,
hepcidin bound to a carrier protein, or both of these hepcidin species.
Lastly, the presence of hepcidin-22 and -20 isoforms, which play no role
in the regulation of iron metabolism, can interfere with the
quantification of hepcidin-25 in immunoassays that use antibodies that
react with all of these hepcidin isoforms.
(5.) Farnaud S, Rapisarda C, Bui T, Drake A, Cammack R, Evans RW.
Identification of an iron-hepcidin complex. Eur J Appl
Physiol 2009;106:51-9.
(138.) Tamary H, Shalev H, Perez-Vraham G, Zoldan M, Levi I,
Swinkels DW, et al. GDF15 and TWSG1 are
both BMP antagonists produced by erythroblasts and putative components
of the erythroid regulator that can inhibit hepcidin expression in
vitro. Gut
2004;53:735-43.
(112.) Roe MA, Collings R, Dainty JR, Swinkels DW, Fairweather-Tait
SJ. Furthermore, as the field moves toward
the use of hepcidin-related therapies, it should be realized that the
outcome of assays that are used to monitor the fate of hepcidin during
antihepcidin therapy may be affected by compounds that interfere with
hepcidin. The iron-regulatory peptide hormone hepcidin:
expression and cellular localization in the mammalian kidney. The
results of this study suggest that administration of antihepcidin
therapies alone or in combination with erythropoiesis-stimulating agents
may improve patients' erythropoietic response and allow the use of
lower EPO doses to avoid the potential detrimental effects of high EPO
concentrations. Most patients with iron-refractory
IDA are resistant to dietary iron supplementation, owing to a defect in
the TMPRSS6 gene encoding matriptase-2. Blood 2005;106: 1864-6.
(210.) Semenza GL. The ability
of hepcidin to bind iron and other divalent metals suggests there may be
a nonhormonal role for hepcidin in iron metabolism or a conformational
mechanism for uptake of divalent metals as part of hepcidin's
hormonal role in regulating ferroportin degradation.
(14.) Suzuki H, Toba K, Kato K, Ozawa T, Tomosugi N, Higuchi M, et
al. The hepcidin/ferritin ratio is also found to be
low in patients with these disorders (135, 137, 138, 140-142). The microcytic red cell and the anemia
of inflammation. Identification of TWSG1 as a second novel
erythroid regulator of hepcidin expression in murine and human cells.
Blood 2009;114:181-6.
Employment or Leadership: H. Infections are
associated with marked changes in iron homeostasis (152).
Malaria-associated anemia has been found to be associated with low serum
iron and increased hepcidin concentrations, causing iron withholding in
the RE system that ultimately leads to iron-restricted erythropoiesis
(115, 118, 153-156). J Endocrinol 2008;197:241-9.
(180.) Tussing-Humphreys LM, Nemeth E, Fantuzzi G, Freels S, Guzman
G, Holterman AX, Braunschweig C. Hepcidin expression in mouse retina and its regulation via
lipopolysaccharide/Toll-like receptor-4 pathway independent of Hfe.
Biochem J 2008;411:79-88.
Acknowledgments: We thank Mirian Janssen and Paul Brons and the
members of the Dutch HEPCIKID (HEPCIdin in patients with KIdney Disease)
consortium, Jack Wetzels, Carlo Gaillard, Roos Masereeuw, Jaap Joles,
and Hilde Peters, for useful discussions on the diagnostic potential for
hepcidin measurements in clinical practice; Fred Sweep, Alec Ross, Guus
Kortman, Rieneke Terink, Susanne van Santen, Lucas van Eijk, Tessel
Galesloot, Louise de Swart, Charlotte Schaap, Erwin Wiegerinck, Coby
Laarakkers, Siem Klaver, Rian Roelofs, Anneke Geurts-Moespot, Nicolai
Grebenchtchikov, and other members of the Nijmegen Iron Group for
stimulating discussions on hepcidin methodology and its clinical
utility; Hans Willems for discussion on assay harmonization; and Hanka
Venselaar and Erwin Kemna for their contribution to the figures.
(140.) Casanovas G, Swinkels DW, Altamura S, Schwarz K, Laarakkers
CM, Gross HJ, et al. Anemia of inflammation: the cytokine-hepcidin
link. Blood
2009;113:5277-86.
The functional signaling routes by which (a) iron status, (b)
erythropoietic activity, (c) hypoxia, and (d) inflammation affect
hepcidin expression are increasingly being investigated. ASH Annu
Meeting Abstracts 2008;112:2676.
(62.) Lakhal S, Schoedel J, Townsend AR, Pugh CW, Ratcliffe PJ,
Mole DR. A decrease in hepcidin results in
the release of stored iron and an increase in dietary iron absorption.
On the other hand, infection and inflammation cause an increase in
hepcidin synthesis. Thus, in chronic mild inflammatory
conditions, such as obesity or the metabolic syndrome, even a mild
hepcidin excess may be sufficient to alter the balance between iron loss
and iron uptake toward iron deficiency.
Much is still unknown on the origin of the smaller isoforms of
hepcidin, although data suggest that calcium-independent tissue activity
in pancreas extracts might lead to the systemic N-terminal truncation of
hepcidin-25 to hepcidin-22, and that dipeptidylpeptidase 4 is involved
in the processing of hepcidin-22 into hepcidin-20 (9, 10). J
Biol Chem 2009;284:24155-67.
In ACD, IL-6 and other cytokines induce hepcidin concentrations,
resulting in iron sequestration in macrophages and leading to
hypoferremia. Nat Rev Microbiol 2008;6: 541-52.
(220.) Braliou GG, Verga Falzacappa MV, Chachami G, Casanovas G,
Muckenthaler MU, Simos G. Results of the first international round robin for the
quantification of urinary and plasma hepcidin assays: need for
standardization. These promises brought about a large series of
studies that examined hepcidin concentrations in patients with CKD. Soon after its discovery and during the
years thereafter, hepcidin was recognized as potentially relevant in CKD
because it may be responsible for the often-observed imbalance between
iron homeostasis and ESA resistance (50, 166). This apparent circadian rhythm of hepcidin
concentrations may be regulated by transcription factors such as
upstream stimulatory factor and c-Myc/Max through E-boxes (110). Blood
2006;108:3730-5.
(47.) Babitt JL, Huang FW, Wrighting DM, Xia Y, Sidis Y, Samad TA,
et al. Some of these studies also demonstrated correlations
between hepcidin and iron or transferrin saturation (169, 170). Subsequently, iron availability for the erythron becomes
limiting and contributes to the development of ACD (59, 75, 81, 160,
161). Haematologica 2007;92:583-8
Decreased hepcidin expression has been reported in response to
hypoxia in vivo (58, 59). Increased adipose tissue expression of hepcidin in severe obesity is
independent from diabetes and NASH. Is
hepcidin-25 a clinically relevant parameter for the iron status in
hemodialysis patients? J Ren Nutr 2010;20:S77-83.
[FIGURE 3 OMITTED]
(15.) Tomosugi N, Kawabata H, Wakatabe R, Higuchi M, Yamaya H,
Umehara H, Ishikawa I. J Biomed
Biotechnol 2010;2010:329646.
Hepcidin in iron-refractory IDA. This algorithm
provided insight into the interrelation of these pathways by showing
that hepcidin inhibition by erythropoiesis strongly interferes with
hepcidin upregulation by iron and that inflammation strongly increases
hepcidin regardless of iron status and erythropoietic activity. IL-6 mediates hypoferremia of inflammation by inducing the
synthesis of the iron regulatory hormone hepcidin. In these
conditions, dysregulation of hepcidin synthesis as a consequence of
reactive oxygen species, endoplasmic reticulum stress, and cytokine tumor necrosis factor-[alpha]-mediated pathways may contribute to
relatively decreased hepcidin synthesis and iron accumulation (59,
67-70, 144). However, how
erythropoiesis regulates hepcidin is not clear yet. In
addition, hepcidin's potential to become a target of treatment was
quickly acknowledged. Anti-interleukin 6 receptor antibody tocilizumab reduces the
level of serum hepcidin in patients with multicentric Castleman's
disease. These
molecules, like BMPs are members of the transforming growth
factor-[beta] family and thus possibly act through effects on the
BMP/SMAD pathway (Fig. Serum hepcidin concentrations decreased, and an increase
in iron status and intestinal absorption was observed in individuals
with weight loss (182, 183). Blood
2005;106:1092-7.
(43.) De Domenico I, Nemeth E, Nelson JM, Phillips JD, Ajioka RS,
Kay MS, et al. However, MS methods can also be
automated (101, 102), and would have to be optimized for hepcidin
because its amphiphatic character makes it readily stick to laboratory
plastics, especially when relatively small sample volumes are used in
large tubes.
(42.) Keel SB, Abkowitz JL. 4).
(10.) Valore EV, Ganz T. Blood 2010;115:3810-6.
Further comparison of the analytical characteristics of various
published assays is incomplete, because not all studies have reported
these characteristics in accordance with the STARD (STAndards for the
Reporting of Diagnostic accuracy studies) procedures (103) or validated
the reported assays according to recommendations of the International
Conference of the Harmonization (ICH) of analytical procedures (104).
Nonetheless, the scientific and medical community was informed on the
status and agreement of the current hepcidin methods by a recent
international send-out of samples for urine and serum hepcidin
measurement in 2009, the so-called "Round Robin 1." In this
study the correlations between the participating methods were generally
high and the between-sample and analytical variation of most methods
were similar (105). (97)
Sandwich ELISA Butterfield et al. Moreover, hepcidin concentrations in these patients
were associated with increased concentrations of monocyte
chemoattractantprotein-1 and vascular damage. Blood Cells Mol Dis 2010;44:16-21.
(80.) Kulaksiz H, Gehrke SG, Janetzko A, Rost D, Bruckner T,
Kallinowski B, Stremmel W. Autocrine formation of hepcidin induces iron retention in human
monocytes. 1), and the high degree of conservation of
hepcidin among a wide range of species, which diminishes the elicitation
of an immune response in host animals (50).
(212.) Yu PB, Hong CC, Sachidanandan C, Babitt JL, Deng DY, Hoyng
SA, et al. Furthermore, sample throughput is likely to be
higher for ELISA than for MS assays. Quantitation of hepcidin in serum using
ultra-high-pressure liquid chromatography and a linear ion trap mass
spectrometer. There are multiple potential opportunities for cross
communication among these pathways, and experimental evidence shows that
these pathways do not function completely independently of each other.
Anti-IL-6-receptor antibody (tocilizumab) was shown to suppress
IL-6-induced hepcidin production in Castleman disease (a rare disorders
with systematic inflammation and anemia), and it improved anemia in
arthritic monkeys (214-217). 4) (55-57). Eur J Appl Physiol 2010;110: 877-83.
(167.) Viatte L, Vaulont S. Possibly, these increased hepcidin concentrations
might be advantageous in the protection against extracellular growing
microorganisms by decreasing the extracellular supply of iron. 3) [reviewed in (44)]. Best
Pract Res Clin Gastroenterol 2009;23:171-83.
(86.) Murao N, Ishigai M, Yasuno H, Shimonaka Y, Aso Y. Clin Chem
2008;54:1584-6.
(191.) Aigner E, Theurl I, Theurl M, Lederer D, Haufe H, Dietze O,
et al. Br J Biomed Sci 2009; 66:150-7.
SECOND-GENERATION (QUANTITATIVE) HEPCIDIN ASSAYS
(94.) Altamura S, Kiss J, Blattmann C, Gilles W, Muckenthaler MU.
SELDI-TOF MS detection of urinary hepcidin. However, because the defect is downstream of
hepcidin, these patients do not have low hepcidin concentrations. Biochem J 2010;427:289-96.
(111.) Bozzini C, Campostrini N, Trombini P, Nemeth E, Castagna A,
Tenuti I, et al. As such, we recommend standardization of
sampling time to minimize within-individual and (pre)analytical
variability in clinical studies exploiting hepcidin measurements.
Hepcidin in IDA. Dorsomorphin inhibits BMP signals required for embryogenesis and iron metabolism. Am
J Kidney Dis 2009;53: 584-95.
Authors' Disclosures or Potential Conflicts of Interest: Upon
manuscript submission, all authors completed the Disclosures of
Potential Conflict of Interest form. Haematologica
2010;95:1660-7.
(143.) Porter JB. J Nutr
Biochem 2010;21:749-56.
(84.) Kemna E, Tjalsma H, Laarakkers C, Nemeth E, Willems H,
Swinkels D. neutralized hepcidin by
a monoclonal antibody in the Brucella abortus mouse model of anemia of
inflammation and found it to restore responsiveness to EPO (211). However, in this study increased hepcidin
concentrations appeared insufficient for the development of anemia
(195), suggesting that compensation by increased erythropoiesis through
increased EPO production may explain the lack of anemia in cancer
despite increased hepcidin concentrations (196).
Hepcidin in heart diseases. Clin Chem 2003;49:19-20.
(38.) Ramey G, Deschemin JC, Durel B, Canonne-Hergaux F, Nicolas G,
Vaulont S. Eur J Appl Physiol 2009;106:435-43.
(216.) Nishimoto N, Kanakura Y, Aozasa K, Johkoh T, Nakamura M,
Nakano S, et al. Maternal serum hepcidin is low at term and
independent of cord blood iron status. 4). Hereditary
hemochromatosis due to resistance to hepcidin: high hepcidin
concentrations in a family with C326S ferroportin mutation. Iron and its relation to immunity and
infectious disease. J Pharmacol
Toxicol Methods 2009;59:171-80.
(135.) Gardenghi S, Marongiu MF, Ramos P, Guy E, Breda L, Chadburn
A, et al. Alternatively, the otherwise expected increased
circulating concentrations in patients with decreased renal filtration
may be offset by a compensatory feedback decrease in hepatic hepcidin
production.
The increase in hepcidin expression with inflammation is primarily
mediated by interleukin-6 (IL-6). Eur J Appl Physiol 2008;103:
381-91.
(4.) Farnaud S, Patel A, Evans RW. Gastroenterology 2006;131:788-96.
(184.) Matsumoto M, Tsujino T, Lee-Kawabata M, Naito Y, Akahori H,
Sakoda T, et al. The solution
structure of human hepcidin, a peptide hormone with antimicrobial
activity that is involved in iron uptake and hereditary hemochro
matosis. Int J Obes
2010;34:1772-4.
(125.) van Dijk BA, Laarakkers CM, Klaver SM, Jacobs EM, van Tits
LJ, Janssen MC, Swinkels DW. Lancet 2006;367:133-43.
(128.) Sham RL, Phatak PD, Nemeth E, GanzT. One study
revealed that hepcidin concentrations of EPO responders did not differ
from those of hyporesponders (176), whereas cross-sectional studies
among HD patients and a prospective study among patients with combined
CKD and chronic heart failure revealed that nonresponders had low
hepcidin concentrations (32, 170, 177). Hepcidin is not useful as a biomarker for iron needs
in haemodialysis patients on maintenance erythropoiesis-stimulating
agents. LEAP-1, a novel highly disulfide-bonded
human peptide, exhibits antimicrobial activity. Future studies are needed to
assess the position of hepcidin in clinical decision making in these
patients.
(174.) Zaritsky J, Young B, Gales B, Wang HJ, Rastogi A, Westerman
M, et al. Iron absorption in dysmetabolic iron overload syndrome is
decreased and correlates with increased plasma hepcidin. J Clin Invest 2004;113: 1251-3.
Hepcidin Function
(206.) Nemeth E. Hepcidin in the management of
patients with mild nonhemochromatotic iron overload: fact or fiction? J
Hepatol 2008;49:680-5.
Hepcidin measurements appear to have potential utility in
diagnostic algorithms to distinguish IDA from ACD and the combined
presence of IDA/ACD. Blood 2010;
116:3627-34.
(46.) Corradini E, Meynard D, Wu Q, Chen S, Ventura P, Pietrangelo
A, Babitt JL. J Clin Invest
2010;120:2395-405.
(151.) Beutler E, Van GC, te Loo DM, Gelbart T, Crain K, Truksa J,
Lee PL. Hepcidin in anemia of chronic heart failure. Measurement of urinary hepcidin levels by SELDI-TOF-MS
in HFE hemochromatosis. The hepcidin produced by these cells, however, is unlikely to
make a significant contribution to systemic circulating concentrations,
but may exert local effects in these tissues (see below).
(66.) Pietrangelo A, Dierssen U, Valli L, Garuti C, Rump A,
Corradini E, et al. Am J
Clin Nutr 2010; 92:1385-92.
Hepcidin produced by various cell types other than hepatocytes (see
above) may have local effects in these tissues. Br J Haematol 2008;142:979-85.
(30.) Swinkels DW, Girelli D, Laarakkers C, Kroot J, Campostrini N,
Kemna EH, Tjalsma H. In this study serum hepcidin was strongly associated with serum
ferritin in men and women, confirming findings of smaller previous
studies (29, 30, 107, 111, 112). Down-regulation of hepcidin resulting from long-term
treatment with an anti-IL-6 receptor antibody (tocilizumab) improves
anemia of inflammation in multicentric Castleman disease. Hepcidin mRNA levels in
mouse liver respond to inhibition of erythropoiesis. Impaired intestinal iron absorption in Crohn's
disease correlates with disease activity and markers of inflammation.
Inflamm Bowel Dis 2006;12: 1101-6.
Since the discovery of hepcidin, there has been a substantial
interest in developing a reliable assay of the peptide hormone in body
fluids. A novel immunological assay for
hepcidin quantification in human serum. Blood 2006;108:1381-7.
Hepcidin-25 is thought to be the major regulator of dietary iron
absorption and cellular iron release. Br J Nutr 2007;97:544-9.
(104.) ICH Steering Committee. Biochimie 2009;91:1335-8.
DISORDERS ASSOCIATED WITH HEPCIDIN DEFICIENCY
(73.) Huang H, Constante M, Layoun A, Santos MM. In patients with hepatitis C virus,
increased transferrin saturation and increased concentrations of serum
ferritin and hepatic iron have been observed. These
findings are corroborated by in vitro studies that showed that the
truncated 22 amino acid and 20 amino acid forms have greatly diminished
and almost complete loss of ferroportin regulatory activity,
respectively, compared with 25 amino acid hepcidin (19).
In addition to its role in regulating systemic iron metabolism,
hepcidin may also contribute to host defense. After
treatment with phlebotomy that normalized iron stores (as assessed by
serum ferritin), these patients have been found to have serum hepcidin
concentrations or serum hepcidin/ferritin ratios within or above
reference intervals (128, 131). Effects of routine
(2.) Pigeon C, Ilyin G, Courselaud B, Leroyer P, Turlin B, Brissot
P, Loreal O. The
low-grade inflammation in obese and dysmetabolic iron overload syndrome
patients, (characterized by the association of increased body iron
stores and metabolic features), is associated with increased hepcidin
concentrations, leading to poor iron absorption and causing ACD (116,
117, 180, 181). Plos One 2009;4: e4581.
(75.) Theurl I, Aigner E, Theurl M, Nairz M, Seifert M, Schroll A,
et al. In congenital iron-loading
anemias, such as [beta]-thalassemia (major and intermedia) and
congenital dyserythropoietic anemia I and II, but also in acquired forms
such as myelodys-plastic syndrome types RA (refractory anemia) and RARS (RA with ringed sideroblasts), the diseased erythron dysregulates iron
homeostasis by inhibiting hepcidin synthesis, even in the presence of
iron overload (134-140). Iron-regulatory protein hepcidin is increased in female athletes
after a marathon. Serum
pro-hepcidin: measuring active hepcidin or a non-functional precursor?
Gut 2005;54: 169-70.
Research Funding: None declared.
References
(192.) Valenti L, Dongiovanni P, Motta BM, Swinkels DW, Bonara P,
Rametta R, et al. Am J Clin Nutr 2009; 89:533-8.
As we discussed previously, basal hepcidin concentrations greatly
depend on the applied measurement method (105). Renal tubular function in
betathalassemia. Anal Chem 2010;82:1551-5.
[6] Human genes: TMPRSS6, transmembrane protease, serine 6; HFE,
hemochromatosis; PER1, period homolog 1 (Drosophila); TIMELESS, timeless
homolog (Drosophila); CLOCK, clock homolog (mouse); HAMP, hepcidin
antimicrobial peptide; TFR2, transferrin receptor 2; HFE2,
hemochromatosis type 2 (juvenile).
(188.) Sullivan JL. The
IL-6-independent pathway may be attributed to increased BMP-2
concentrations, which have been suggested to act synergistically with
IL-6 to induce hepatocyte hepcidin synthesis (193, 194).
(108.) Zhang X, Jin M, Wu H, Nadasdy T, Nadasdy G, Harris N, et al.
Biomarkers of lupus nephritis determined by serial urine proteomics.
Kidney Int 2008;74:799-807.
(171.) Valenti L, Girelli D, Valenti GF, Castagna A, Como G,
Campostrini N, et al. FEBS Lett
2000;480:147-50.
(155.) Howard CT, McKakpo US, Quakyi IA, Bosompem KM, Addison EA,
Sun K, et al. Hepcidin targets ferroportin for degradation in hepatocytes.
Haematologica 2010;95:501-4.
(147.) Zimmermann MB, Troesch B, Biebinger R, Egli I, Zeder C,
Hurrell RF. J Hepatol 2011;54: 173-81.
In recent years, substantial progress has been made by the
introduction of an internal standard to quantify hepcidin-25 in serum
and urine by an updated TOF-MS assay (13, 30). Ineffective erythropoiesis in beta-thalassemia is
characterized by increased iron absorption mediated by downregulation of
hepcidin and up-regulation of ferroportin. One study showed a blunted hepcidin response to
inflammatory stimuli in hemochromatosis (HFE) knock-out mice (76),
whereas results of other studies of the same mice or a patient with an
HFE mutation suggest that inflammatory induction of hepcidin is
independent from the HFE protein (77, 78). Additional studies to investigate the
possibility that local urinary infections or tubular dysfunction can
contribute to hepcidinuria are warranted.
(32.) Costa E, Swinkels DW, Laarakkers CM, Rocha-Pereira P, Rocha
S, Reis F. Cellular iron is mostly bound
within iron protoporphyrin (heme) and iron--sulfur clusters, which serve
as enzyme cofactors, or stored within the core of ferritin multimers.
Without adequate iron, cells lose their capacity for electron transport and energy metabolism. (Pre) analytical imprecision, between-subject
variability, and daily variations in serum and urine hepcidin:
implications for clinical studies. Blood 2007;109:5027-35.
(129.) Drakesmith H, Schimanski LM, Ormerod E, Merryweather-Clarke
AT, Viprakasit V, Edwards JP, et al. The first reliable assays to quantify hepcidin in human body
fluids have recently been developed, and proof-of-principle studies in
human iron disorders highlight hepcidin as a promising novel tool in
diagnostic medicine, as outlined in Table 2. As such hepcidin was
described as a promising companion diagnostic marker to predict ESA
responsiveness, and to guide treatment with ESA and intravenous iron. We
conclude by highlighting the most promising applications of hepcidin
assays in diagnostic medicine.
Preclinical studies and some clinical studies have provided
proof-of-concept for synthetic hepcidin-25, small hepcidin peptides, BMP
agonists, and HIF stabilizers to prevent iron overload attributed to
hepcidin deficiency.
(24.) Kulaksiz H, Fein E, Redecker P, Stremmel W, Adler G, Cetin Y.
Pancreatic beta-cells express hepcidin, an iron-uptake regulatory
peptide. Clin J Am Soc Nephrol 2010;5: 1010-4.
(110.) Bayele HK, McArdle H, Srai SK. Moreover, hepcidin was found to modulate
lipopolysaccharide-induced transcription in both cultured macrophages
and in vivo mouse models (40). 2-Oxoglutarate-dependent oxygenases control
hepcidin gene expression. Heparin: a potent inhibitor of hepcidin expression in
vitro and in vivo. Regulation of hepcidin: Insights from biochemical analyses
on human serum samples. Therefore, there is need
for further studies on serum hepcidin concentrations in larger and
well-designed studies to resolve the aforementioned discrepancies in the
literature.
(158.) Sazawal S, Black RE, Ramsan M, Chwaya HM, Stoltzfus RJ,
Dutta A, et al. Development of novel therapeutic strategies that
target HIF-1. Eur J Heart Fail
2010;12:943-50.
Urine hepcidin measurements may be attractive, especially for use
in research and measurements in children and patients in the
underdeveloped world, because this matrix allows noninvasive sampling.
Nevertheless, although a significant relationship was found between the
hepcidin concentrations of urine-serum sample pairs from healthy
controls and patients with disorders of iron metabolism (12, 29, 107),
urine hepcidin concentrations may not always accurately reflect serum
hepcidin concentrations. Primaire hemochromatose door
ferroportinegenmutaties: is er een plaats voor hepcidine in de
diagnostiek? Ned Tijdschr Klin Chem Labgeneesk 2011;36:6-11.
HEPCIDIN ANTAGONISTS
(103.) Bruns DE. Hepcidin, a urinary
antimicrobial peptide synthesized in the liver. Supraphysiological doses of exogenous BMP-6 for 10 days also were
reported to improve hepcidin deficiency, reduce serum iron, and
redistribute tissue iron to appropriate storage sites (RE macrophages,
spleen) in a mouse model for HFE hemochromatosis (209). Furthermore, CRP and IL-6 were shown
to be less relevant predictors in the setting of renal insufficiency
(16,170,172-175). Of the currently
available commercial immunochemical research kits for serum hepcidin, we
found the RIA and enzyme-immunoassay kits of Bachem (purchased November
2009 and August 2010, respectively) to be suitable to differentiate
between hepcidin concentrations in serum samples of controls and
patients with various iron disorders, whereas the bioactive hepcidin kit
of DRG Instruments, (purchased October 2009) gave similar concentrations
for all samples and could not discriminate between iron metabolism
disorders (unpublished results).
(195.) Hohaus S, Massini G, Giachelia M, Vannata B, Bozzoli V,
Cuccaro A, et al. However, absolute hepcidin concentrations differed
widely between the assays. Proteome Sci 2008;6:28.
CHALLENGES FOR HEPCIDIN ASSAYS
(117.) Aeberli I, Hurrell RF, Zimmermann MB. Elevated systemic hepcidin and iron
depletion in obese premenopausal females. Correlations between the expression
of TWSG1 expression and serum iron parameters and serum hepcidin
concentrations have not yet been determined in humans. Suppression of
hepcidin during anemia requires erythropoietic activity. Evidence for distinct pathways of hepcidin regulation by acute
and chronic iron loading in mice. Regulation of iron homeostasis in anemia of chronic disease and
iron deficiency anemia: diagnostic and therapeutic implications. Hepcidin: a putative iron-regulatory
hormone relevant to hereditary hemochromatosis and the anemia of chronic
disease. Eur J Haematol 2010; 85:345-52.
prophylactic supplementation with iron and folic acid on admission
to hospital and mortalityin preschool children in a high malaria
transmission setting: community-based, randomised, placebo-controlled
trial. (98)
Schwarz et al. An Hfe-dependent pathway mediates hyposideremia in
response to lipopolysaccharide-induced inflammation in mice. BMP-2 administration in mice was found to increase
liver hepcidin expression and reduce serum iron concentrations in vivo
(208). Clin J Am Soc Nephrol 2009;4:1051-6.
(208.) Babitt JL, Huang FW, Xia Y, Sidis Y, Andrews NC, Lin HY.
Modulation of bone morphogenetic protein signaling in vivo regulates
systemic iron balance. Advances in quantitative hepcidin measurements by
time-of-flight mass spectrometry. Because these patients tend to be anemic, even a mild
hepcidin excess can be considered to be inappropriately high for the
level of anemia. A novel mono clonal antibody immunoassay for the
detection of human serum hepcidin. Blood 2006;108:3204-9.
There is an increasing demand for preclinical tools to assess the
efficacy of hepcidin-related therapies. Adipose tissue is an active
endocrine organ that releases several cytokines and adipokines, which
can contribute to the development of a low-grade systemic inflammation.
Furthermore, adipose tissue also can produce hepcidin (21). BMJ 2011;342:c7251.
Iron is required for the function of oxygen-binding molecules,
mainly hemoglobin and myoglobin, and iron-containing enzymes, including
the cytochrome system in mitochondria. Hepcidin is down-regulated in alcoholic liver
injury: implications for the pathogenesis of alcoholic liver disease.
Alcohol Clin Exp Res 2006;30: 106-12.
(3.) Jordan JB, Poppe L, Haniu M, Arvedson T, Syed R, Li V, et al.
Hepcidin revisited, disulfide connectivity, dynamics, and structure. This
situation suggests that reference intervals may have limitations when
used for the interpretation of individual hepcidin concentrations. Antihepcidin antibody treatment modulates iron metabolism and
is effective in a mouse model of inflammation-induced anemia. Hepcidin and iron-related gene expression in
subjects with Dysmetabolic Hepatic Iron Overload. The authors concluded that hepcidin-20, rather than
hepcidin-25, may be helpful for the diagnosis of acute myocardial
infarction (14).
(99.) Schwarz P, Strnad P, von FG, Janetzko A, Krayenbuhl P, Adler
G, Kulaksiz H. Quantification of hepcidin-25 in human serum by
isotope dilution micro-HPLC-tandem mass spectrometry. Haematologica 2009; 94:1748-52.
(181.) Ruivard M, Laine F, Ganz T, Olbina G, Westerman M, Nemeth E,
et al. Therefore,
differentiation between these conditions is often achieved by combining
various biochemical markers of iron metabolism. http://www.ifcc.org/
index.asp?cat=Publications&scat=eJIFCC_&suba =
VoL13_No_3&subx=Development_Of_Reference_
Methcds_And_Reference_Materials_byJean-Claude_
Forest_Cari_A_Burtis&zip=1&dove=1&zona=full&
numero=&aq=1 (Accessed October 2011).
Hepcidin concentrations can also be induced by targeting the BMP
pathway (Fig. (94)
Ward et al. Blood
2008;111:5727-33.
(214.) Song SN, Tomosugi N, Kawabata H, Ishikawa T, Nishikawa T,
Yoshizaki K. This increased synthesis leads to a deficiency of
iron available for erythropoiesis, and is considered to be the mechanism
underlying reticuloendothelial (RE) iron sequestration, intestinal iron
absorption impairment, and low serum iron concentrations characteristic
of anemia of chronic disease.
(222.) Tjalsma H, Laarakkers CM, van Swelm RP, Theurl M, Theurl I,
Kemna EH, et al. Hepcidin was originally
identified as an antimicrobial peptide (1, 11). Fleming, [3]
and Dorine W. J Biol Chem 2001;276:7811-9.
(87.) Kobold U, Dulffer T, Dangl M, Escherich A, Kubbies M,
Roddiger R, Wright JA. Viral infection and iron
metabolism. The relatively high hepcidin
concentrations in some patients might be a consequence of the
transferrin saturation that remained increased despite phlebotomy. On the basis of theoretical
calculations, 11% of hepcidin was estimated to be freely circulating
(28). Additional data were reported that
suggested an atherogenic function of hepcidin in a study that revealed
that ex vivo hepcidin-25 treatment of differentiating monocytes from
patients with the metabolic syndrome induced monocyte chemoattractant protein-1 (192). Quantitation of
hepcidin from human and mouse serum using liquid chromatography tandem
mass spectrometry. Blood 2005;106: 3979-84.
(119.) Altamura S, D'Alessio F, Selle B, Muckenthaler MU. J Gastroenterol 2011; 46:648-56.
(190.) Barisani D, Pelucchi S, Mariani R, Galimberti S, Trombini P,
Fumagalli D, et al. In IDA patients, and also in patients with low
ferritin concentrations without anemia, secondary to blood losses or
insufficient dietary intake, hepcidin concentrations have been found to
be very low, often below the lower limit of detection of the employed
assays (13, 29).
(144.) Swinkels DW, Drenth JP. J Mol Med 2011.
[FIGURE 4 OMITTED]
(91.) Anderson DS, Heeney MM, Roth U, Menzel C, Fleming MD, Steen
H. Evidence for the latter explanation comes from the
finding of increases of only 1- to 6-fold of serum hepcidin
concentrations in patients with glomerular dysfunction (15, 16, 29, 31,
32) compared with the 20- to 30-fold increase of serum
[[beta].sub.2]-microglobulin. Prohepcidin: expression and cell specific
localisation in the liver and its regulation in hereditary
haemochromatosis, chronic renal insufficiency, and renal anaemia. Anal Biochem 2002;301:49-56.
(116.) del Giudice EM, Santoro. finding electric problems in a car can be challenging. It is very difficult to trace one of the hundreds of wires in a vehicle. You need a specialized electric automotive repair shop to find most electric problems in a vehicleN, Amato A, Brienza C, Calabro P,
Wiegerinck ET, et al. On the
other hand, increased hepcidin concentrations may lead to iron
deficiency and blunt the efficacy of iron fortification programs by
decreasing iron absorption (157). HIF-2alpha, but not HIF-1alpha, promotes iron absorption
in mice. Novel urine hepcidin assay by mass spectrometry. Acta Haematol
2009;122:226-9.
Joyce J.C. Hepcidin
agonists could be useful to prevent iron overload attributed to hepcidin
deficiency, such as HH, and especially [beta]-thalassemias and other
iron-loading anemias, and possibly some acquired forms of
non-hemochromatotic iron-overload diseases. J Mol Med 2010;88:477-86.
Recent observations suggest that the erythropoietic signal may
include 1 or more proteins released at sites of active erythropoiesis,
i.e., growth differentiation factor-15 (growth differentiation factor-15
(GDF15) and twisted gastrulation protein homolog-1 (TWSG1). 1) (3). It is likely that additional
erythropoietic factors downregulating hepcidin expression will be
identified.
(11.) Park CH, Valore EV, Waring AJ, Ganz T. Mass
spectrometry-based hepcidin measurements in serum and urine: analytical
aspects and clinical implications. Haematologica 2008;93:1473-9.
[1] Department of Laboratory Medicine, Laboratory of Genetic,
Endocrine and Metabolic Disorders, [2] Hepcidinanalysis.com, Radboud
University Nijmegen Medical Centre, Nijmegen, the Netherlands; [3] Saint
Louis University School of Medicine, St. Intracellular iron stores
communicate with hepcidin via BMPs, particularly BMP-6, in a paracrine or autocrine fashion. Severe iron
deficiency blunts the response of the iron regulatory gene Hamp and
proinflammatory cytokines to lipopolysaccharide. J Clin Invest
2007;117:1926-32.
Hepcidin in acquired forms of nonhemochromatotic iron overload.
Several nonhereditary liver diseases such as excessive alcohol
consumption, nonalcoholic fatty liver disease and nonalcoholic
steatohepatitis are associated with mild hepatic iron overload. Kroot, [1] Harold Tjalsma, [1,2] Robert E. Possibly hepcidin should be
regarded as a marker of response rather than resistance to ESA treatment
in these patients.
(7.) Melino S, Garlando L, Patamia M, Paci M, Petruzzelli R. Blood 2005;106:2196-9.
(177.) Bratescu LO, Barsan L, Munteanu D, Stancu S, Mircescu G. Am J Hematol
2011;86: 107-9.
(200.) Peeling P, Dawson B, Goodman C, Landers G, Wiegerinck ET,
Swinkels DW, Trinder D. Hepcidin as a predictor of response to epoetin therapy in
anemic cancer patients. Relationship of hepcidin with parasitemia and anemia among
patients with uncomplicated Plasmodium falciparum malaria in Ghana. Phlebotomies or erythropoietin injections allow mobilization
of iron stores in a mouse model mimicking intensive care anemia. However, the redox activity of iron can also
cause damage, primarily by the production of reactive oxygen radicals.
As such, iron concentrations must be tightly regulated both at the
cellular and the systemic level. Anemia of chronic disease. BMP6 treatment compensates for the
molecular defect and ameliorates hemochromatosis in Hfe knockout mice.
Gastroenterology 2010;139:1721-9.
For Hodgkin lymphoma we recently demonstrated that increased IL-6
production is associated with induction of hepcidin, which contributes
to the iron-restricted anemia of chronic disease often observed at
Hodgkin lymphoma diagnosis. Mass spectrometry analysis of hepcidin peptides in
experimental mouse models. Patients with most forms of
HH have the inability to appropriately upregulate hepcidin synthesis in
response to increased iron stores. Large and well-designed studies exploiting
harmonized assays are required to more firmly establish the position of
hepcidin in diagnostic medicine. Contribution of
STAT3 and SMAD4 pathways to the regulation of hepcidin by opposing
stimuli. Iron is
necessary for microbial growth, and reductions in plasma iron are
bacteriostatic. Nat Med 2007;13:1096-101.
Several physiologic and pathologic processes regulate the synthesis
of hepcidin (Fig. TLR4-dependent hepcidin expression by myeloid cells in response
to bacterial pathogens. Neither of these
factors, however, appears to be required to mediate the decrease in
hepcidin observed with EPO administration. Blood Cells Mol Dis 2008;40:339-46.
Montosi G, Chen S, et al. Blood 2011;117:997-1004.
(154.) de Mast Q, van Dongen-Lases EC, Swinkels DW, Nieman AE,
Roestenberg M, Druilhe P, et al. Consistent with this iron
loading, low hepcidin concentrations have been found in these patients,
along with other changes in the expression of iron-transport genes
[reviewed in (159)]. We
observed lower serum hepcidin concentrations in premenopausal women than
in postmenopausal women (median 4.1 nmol/L vs 8.5 nmol/L) (109).
Hepcidin concentrations in men were constant over age (median 7.8
nmol/L). Mutations in the gene encoding the cellular iron
exporter ferroportin can also cause HH. J Clin Endocrinol
Metab 2009;94:5102-7.
(219.) Xiao JJ, Krzyzanski W, Wang YM, Li H, Rose MJ, Ma M, et al.
Pharmacokinetics of anti-hepcidin monoclonal antibody Ab 12B9m and
hepcidin in cynomolgus monkeys. Hepcidin
in CKD also has been associated with iron-restricted erythropoiesis, as
reflected by the relation of hepcidin with lower hemoglobin and/or
reticulocyte counts (31, 169, 171). Blood
2009;114:493-4.
(64.) Wrighting DM, Andrews NC. Int J Obes 2009;33:1111-7.
(209.) Corradini E, Schmidt PJ, Meynard D, Garuti C,
HEPCIDIN AGONISTS
(164.) Thomas C, Kobold U, Balan S, Roeddiger R, Thomas L. However, these assays could be used
to measure hepcidin only in a semiquantitative manner.
(82.) Brookes MJ, Sharma NK, Tselepis C, Iqbal TH. Gardenghi et
al. As a result the outcomes of studies to assess the
diagnostic value of hepcidin largely have depended on the definition of
surrogate gold standards. The hepcidin-binding site on ferroportin is
evolutionarily conserved. Altogether, these limitations should be kept in mind
during the interpretation of urine hepcidin data and the decision to
develop dedicated point-of-care devices for urine hepcidin measurements.
(17.) Tessitore N, Girelli D, Campostrini N, Bedogna V, Pietro SG,
Castagna A, et al. In
general, these studies have reported increased hepcidin concentrations
in CKD patients compared with healthy controls (15, 16, 29, 31, 32, 88,
89, 96, 167-169). J Biol Chem 2011;286:4090-7.
(169.) Weiss G, Theurl I, Eder S, Koppelstaetter C, Kurz K,
Sonnweber T, et al. The utility of multivariate analysis
in the study of hepcidin. Hepcidin: from
discovery to differential diagnosis. International Conference on
Harmonisation of Technical Requirements for Registration of
Pharmaceuticals for Human Use: ICH harmonised tripartite guideline text
on validation of analytical procedures. Situations in which demand for
circulating iron is increased (particularly erythropoietic activity)
elicit a decrease in hepatocellular hepcidin synthesis. Resistance to hepcidin is conferred
by hemochromatosis-associated mutations of ferroportin. Hepcidin
expression and iron transport in alveolar macrophages. The excretion of the latter low molecular
weight protein is known to be almost completely governed by glomerular
filtration. Soluble
HJV, which also acts as an antagonist of BMP signaling, decreases
hepcidin baseline expression in mice, mobilizes RE-system (splenic) iron
stores, increases liver iron content and concurrently increases serum
concentrations (208). Erythropoietin administration in humans causes a marked and
prolonged reduction in circulating hepcidin. Whether HIFs directly bind to the
hepcidin promoter is currently controversial. Louis, MO.
(194.) Maes K, Nemeth E, Roodman GD, Huston A, Esteve F, Freytes C,
et al. The introduction of ESAs, such as EPO,
has allowed effective treatment of anemia in patients with CKD. Such pathogens are
common in malaria-endemic regions. In cases in which interference has occurred, assays must be
revalidated for this specific application before definite conclusions on
the efficacy of the therapy can be drawn. This latter observation suggests a role
for hepcidin in modulating acute inflammatory responses to bacterial
infection.
(178.) Ho J, Lucy M, Krokhin O, Hayglass K, Pascoe E, Darroch G, et
al. The prevalence of iron deficiency is
high among athletes. Haematologica
2010;95:505-8.
(93.) Bansal SS, Halket JM, Bomford A, Simpson RJ, Vasavda N, Thein
SL, Hider RC. Iron in arterial plaque: modifiable risk factor
for atherosclerosis. Am J Physiol Gastrointest Liver
Physiol 2006;291:G229-37.
(65.) Verga Falzacappa MV, Vujic SM, Kessler R, Stolte J, Hentze
MW, Muckenthaler MU. Erythropoietin mediates hepcidin expression in hepatocytes
through EPOR signaling and regulation of C/EBPalpha. Macrophage iron, hepcidin, and atherosclerotic
plaque stability. Simple and
sensitive quantification of bioactive peptides in biological matrices
using liquid chromatography/selected reaction monitoring mass
spectrometry coupled with trichloroacetic acid clean-up. It
appears that hepcidin values, like those of other hormones, should be
interpreted in the context of other indices of iron metabolism. High-sensitive radioimmunoassay for
human serum hepcidin. Haematologic data, iron parameters and molecular findings in
two new cases of iron-refractory iron deficiency anaemia. Defects in TfR2 and HFE lead to
decreased hepcidin concentrations via the extracellular signal-regulated
kinases: the mitogen-activated protein kinase (ERK/MAPK) pathwayand/or
the bone morphogenetic protein/mothers against decapentaplegic homolog (Drosophila) (BMP/SMAD) pathway (Fig. PLoS ONE 2011;6: e16762.
(126.) Piperno A, Girelli D, Nemeth E, Trombini P, Bozzini C,
Poggiali E, et al. (87)
Bansal et al. Evaluation of hepcidin isoforms in hemodialysis
patients by a proteomic approach based on SELDI-TOF MS. Further studies in which hepcidin response to iron
supplementation is used as a proxy for the gold standard of iron status
would be informative. Exercise as a mediator of hepcidin activity in
athletes. By
contrast, mutational defects that result in the loss of ferroportin
function cause cellular iron overload due to compromised iron export.
Such patients thus have some phenotypic characteristics which vary from
those of classical HH and have been reported to have high (urinary)
hepcidin concentrations when untreated (127).
We foresee the following potential applications of hepcidin
measurements in patients diagnosed with or suspected for HH: (a)
screening for the presence of HH in patients with increased ferritin
concentrations; (b) prioritization of genes to be investigated (very low
hepcidin concentrations point to juvenile HH forms); (c) prediction of
which C282Y-homozygous patients will be at risk for iron overload; and
(d) monitoring of phlebotomy treatment (123, 133).
(202.) Troadec MB, Laine F, Daniel V, Rochcongar P, Ropert M,
Cabillic F, et al. (43)
(a) UPLC, ultra-high pressure LC; MS/MS, tandem MS; Q,
quadrupole; HBD, hepcidin-binding domain.
Table 2. Recent advances in the understanding of iron overload in
sideroblastic myelodysplastic syndrome. Hepcidin concentrations have not been
consistently compared between races and there are few studies in
children (113-120). Mild increases in serum hepcidin and
interleukin-6 concentrations impair iron incorporation in haemoglobin during an experimental human malaria infection. Some studies showed that hepcidin is an
appropriate marker in the differentiation of ACD and IDA/ACD but not of
IDA and IDA/ACD (75), whereas others have reported that hepcidin allowed
distinguishing IDA from IDA/ACD but not ACD from IDA/ACD (13,164).
Results of another study have suggested that hepcidin concentrations can
serve as an appropriate marker to differentiate between all 3 groups
(165).
(131.) Wijngaarden P, Hoskam J, Koeken A, Boer JMA, Swinkels DW,
Ermens AAM, Cobbaert CM. Rheumatol Int 2010;30:917-23.
[FIGURE 1 OMITTED]
(196.) Zucker SD. Cell Metab 2008;8:146-56.
(74.) Darshan D, Frazer DM, Wilkins SJ, Anderson GJ. Am J Clin
Nutr 2009;90: 1280-7.
INTERACTION BETWEEN HEPCIDIN REGULATORY PATHWAYS
Several components can interfere with the BMP/ SMAD pathway.
Administration of dorsomorphin, a small inhibitor of BMP signaling,
prevented hepcidin induction by iron in mice (212). Blood 2007;110:4096-100.
(136.) Kearney SL, Nemeth E, Neufeld EJ, Thapa D, Ganz T, Weinstein
DA, Cunningham MJ. Anemia in Hodgkin's lymphoma: the role of
interleukin-6 and hepcidin. In these
so-called nonhemochromatotic iron overload diseases, hepcidin
concentrations are increased, but relatively low for the level of iron
overload, suggesting ineffective liver iron sensing. et al. Clin Chim Acta 2010;411:453-5.
(88.) Bansal SS, Abbate V, Bomford A, Halket JM, Macdougall IC,
Thein SL, Hider RC. Med Sci Sports Exerc
2009;41:1138-45.
Liver iron stores and circulating transferrin-bound iron
(Tf-[Fe.sub.2]) each provide distinct signals to influence hepatocyte hepcidin expression (44-46) and are considered separately (Fig. This difficulty is due
to the small and compact structure of hepcidin, which leaves scarce
antigenic epitopes (Fig. Nat Chem Biol 2008;4:33-41.
Human hepcidin is predominantly produced by hepatocytes as a 25
amino acid peptide (2789.4 Da) (1, 2), that is secreted into the
circulation. Hereditary haemochromatosis. Interleukin-6 induces hepcidin
expression through STAT3. Intravenous iron administration was found not to
influence hepcidin concentrations in hemodialysis (HD) patients that
were withheld from iron and ESA therapy for 2 weeks (169), whereas it
increased hepcidin in iron-naive CKD patients (31, 96). Studies in
patients with multiple myeloma suggest that hepcidin is upregulated in
these patients by both IL-6-dependent and IL-6-independent mechanisms
that may play a role in the anemia often observed in these patients. Moreover, the
response of the hepcidin to oral iron might prove to be a useful test to
evaluate iron absorption in iron deficiency.
(173.) Zaritsky J, Young B, Wang HJ, Westerman M, Olbina G, Nemeth
E, et al. Here, we review the major
advances from studies on the structure, kinetics, regulation, and
function of hepcidin and the current state-of-the-art in hepcidin
assays. Diagnosis and
management of hereditary haemochromatosis. Reduction of serum hepcidin by hemodialysis in pediatric and
adult patients. J Nutr 2001;131: 616S-33S.
(179.) Prowle JR, Westerman M, Bellomo R. Recombinant human hepcidin expressed in Escherichia
coli isolates as an iron containing protein. Bone morphogenetic protein signaling by hemojuvelin regulates
hepcidin expression. (96) (Bachem)
Grebenchtchikov et al. Pathophysiology of transfusional iron overload:
contrasting patterns in thalassemia major and sickle cell disease.
Hemoglobin 2009; 33(Suppl 1):S37-45.
Hepcidin-targeted therapies may improve treatment options for
patients suffering from iron disorders. Hepcidin might also contribute indirectly
to host defense by reducing plasma iron concentrations. The molecular basis of ferroportin-linked hemochromatosis.
Proc Natl Acad SciUSA 2005;102:8955-60.
To date, differences in hepcidin concentrations between the sexes
have not been consistently found (12, 29, 85, 96, 97, 107). Proc Natl Acad SciUSA2001;98: 8160-2.
(163.) Andrews NC. Blood
2011;117:e218-25.
. Exp Biol Med 2007; 232:1014-20.
Hepcidin Synthesis and Structure
(189.) Sullivan JL. Association of body iron stores with low
molecular weight iron and oxidant damage of human atherosclerotic
plaques. Repeated intravenous iron
infusions, on the other hand. Polymorphisms and mutations of human TMPRSS6 in iron deficiency
anemia. J Am Soc Nephrol 16,
49A 2005.
(161.) Fleming RE, Sly WS. Involvement of hepcidin in the anemia of multiple myeloma.
Clin Cancer Res 2008;14:3262-7.
(90.) Campostrini N, Castagna A, Zaninotto F, Bedogna V, Tessitore
N, Poli A, et al. (88)
LC-MS/MS Murphy et al. Mice lacking intestinal HIF2[alpha] have decreased expression of
both ferroportin and divalent metal transporter 1, the principal iron
importer at the apical surface of duodenal enterocytes, and thus fail to
induce iron absorption even upon lowering of hepcidin expression (63).
These data suggest that in hypoxic (or iron deficient) conditions,
expression of HIF2[alpha] promotes iron absorption from the intestine
via increased activity of divalent metal transporter 1 and ferroportin.
This result implies that HIF2[alpha]-induced changes in iron transport
can override the effects of the hepcidin-ferroportin regulatory axis.
(224.) Kemna EH, Tjalsma H, Willems HL, Swinkels DW. Iron
delocalisation in the pathogenesis of ma larial anaemia. Alcohol-dependent
downregulation of C/EBP[alpha], probably through radical oxygen species,
might be responsible for a decrease of hepcidin expression and
subsequent (mild) iron overload in heavy drinkers (69, 70).
Previously published online at DOI: 10.1373/clinchem.2009.140053
(40.) De Domenico I, Zhang TY, Koening CL, Branch RW, London N, Lo
E, et al. These
patients demonstrated an exaggerated increase in serum iron
concentrations upon oral iron loading (132). In a recent study among
elderly individuals ([greater than or equal to]65 years old), the
presence of anemia could not be attributed to increased hepcidin
concentrations, because urinary hepcidin concentrations were
significantly lower among participants with inflammation anemia and iron
deficiency compared with nonanemic controls. This dysregulation is caused by
defects in certain genes encoding for positive regulators of hepcidin
(HFE, TfR2, HJV), or, rarely, the hepcidin gene [hepcidin antimicrobial
peptide (HAMP)] itself [reviewed in (123, 124)]. (29)
Koliaraki et al. Reports on the effect
of a defective HFE/TfR2 pathway on hepcidin upregulation by inflammation
are not consistent. Urinary hepcidin in congenital chronic anemias.
Pediatr Blood Cancer 2007;48:57-63.
(115.) de Mast Q, Syafruddin D, Keijmel S, Olde RT, Deky O, Asih
PB, et al. J Leukoc Biol 2007;82:934-45.
Hepcidin Regulation
Although the number of studies on the role of hepcidin in the
anemia of cancer is limited, these studies have contributed to our
insights regarding the mechanisms involved. Haematologica 2010;95:1068-74.
(58.) Nicolas G, Chauvet C, Viatte L, Danan JL, Bigard X, Devaux I,
et al. Anemia of chronic heart failure has
been found to be associated with low hepcidin concentrations, making
(low-grade) inflammation less likely as the sole underlying mechanism
(184, 185).A study on acute cardiac ischemia showed a transient increase
in serum hepcidin-20 concentrations for the majority of patients
studied, whereas hepcidin-25 remained increased 7 days after the
incident. This situation implies
that until harmonization is achieved, reference intervals as well as
clinical decision limits for certain patient populations specific to the
assay methods should be used. Quantitation of hepcidin in human urine by liquid
chromatography-mass spectrometry. The presence of the iron exporter ferroportin at the plasma membrane
of macrophages is enhanced by iron loading and downregulated by
hepcidin. Serum hepcidin and macrophage iron correlate with
MCP-1 release and vascular damage in patients with metabolic syndrome
alterations. World J Gastroenterol 2007;13:4925-30.
Hepcidin in obesity-related diseases. Although the
smaller forms of hepcidin do not elicit a hypoferremic response, it is
currently unknown whether they retain other identified biological
functions of hepcidin-25 (e.g., in host defense or in metal binding) (4,
6, 11, 43).
(113.) Semrin G, Fishman DS, Bousvaros A, Zholudev A, Saunders AC,
Correia CE, et al. to propose that
exercise-induced increases in hemolysis and hepcidin expression may have
2 effects. Surprisingly, these results are not fully
consistent with those found for patients with CKD (see above), but
suggest that baseline hepcidin concentrations may play a potential role
as a predictive marker to identify patients who either are going to
respond adequately to EPO therapy or need to be excluded from anemia
correction with ESA owing to a low chance of responding.
(49.) Silvestri L, Pagani A, Nai A, De D, I, Kaplan J, Camaschella
C. For
instance, it is possible that "normal" concentrations of
hepcidin in iron deficiency anemia (IDA) are inappropriately high, and
perpetuate iron restriction.
(130.) Mayr R, Janecke AR, Schranz M, Griffiths WJ, Vogel W,
Pietrangelo A, Zoller H. Hepcidin serum levels and resistance to recombinant
human erythropoietin therapy in haemodialysis patients. Blood Cells Mol Dis 2002;29:
327-35.
(77.) Constante M, Jiang W, Wang D, Raymond VA, Bilodeau M, Santos
MM. Afebrile Plasmodium falciparum parasitemia decreases
absorption of fortification iron but does not affect systemic iron
utilization: a double stable-isotope study in young Beninese women. Am J Trop Med Hyg 2011;84: 148-51.
(217.) Kawabata H, Tomosugi N, Kanda J, Tanaka Y, Yoshizaki K,
Uchiyama T. Blood 2006;107:328-33.
(20.) Peyssonnaux C, Zinkernagel AS, Datta V, Lauth X, Johnson RS,
Nizet V. Interpretation of urinary hepcidin data is
difficult because urine concentrations may also depend on glomerular
filtration, tubular reabsorption, local production by tubular epithelial
cells (25), and production by interstitial inflammatory cells (108).
These issues make measurement of hepcidin somewhat disadvantageous in
urine compared to serum and imply that for reliable interpretation of
urine hepcidin concentrations as an alternative for serum
concentrations, information on renal hepcidin production and handling is
needed. Curr Opin Crit Care 2003;9:496-502.
(121.) Van Santen S, de Mast Q, Luty AJ, Wiegerinck ET, van der Ven
A, Swinkels DW. HH comprises several
genetic disorders of iron homeostasis characterized by body iron excess.
This results in body iron overload, which can progress to organ injury,
such as liver fibrosis and cirrhosis (122). Hepcidin-25 is a marker of the
response rather than resistance to exogenous erythropoietin in chronic
kidney disease/chronic heart failure patients. Nat Genet 2008;40: 569-71.
(9.) Schranz M, Bakry R, Creus M, Bonn G, Vogel W, Zoller H.
Activation and inactivation of the iron hormone hepcidin: biochemical
characterization of prohepcidin cleavage and sequential degradation to
N-terminally truncated hepcidin isoforms. Blood 2006;107:3727-32.
(52.) Ashby DR, Gale DP, Busbridge M, Murphy KG, Duncan ND, Cairns
TD, et al. Cell Metab 2008;8:502-11.
* Address correspondence to this author at: Department of
Laboratory Medicine, Laboratory of Genetic, Endocrine and Metabolic
Diseases 830, Radboud University Nijmegen Medical Centre, P.O. Box 9101,
6500 HB Nijmegen, the Netherlands. (86)
Li et al. These
findings are in agreement with results of studies demonstrating that
high erythroid demand for iron blunts hepcidin induction by a
concomitant inflammatory response (50, 72-75). In vivo studies in mice have
demonstrated that only full-length 25 amino acid hepcidin induces
significant hypoferremia when injected intraperitoneally (18). J Biol Chem
2001;276:7806-10.
(142.) Cuijpers ML, Raymakers RA, Mackenzie MA, de Witte TJ,
Swinkels DW. As expected, patients with these mutations have a phenotype
similar to classical HH. In addition, Ganz et al.
(29) developed a competitive (c)ELISA for human serum hepcidin. Hemojuvelin
(HJV), a BMP coreceptor (47), is crucial for hepcidin expression because
various hepcidin regulatory pathways converge at this membrane-bound
protein. (92)
HBD assay De Domenico et al. J Pept Res 2005;66:65-71.
(45.) Ramos E, Kautz L, Rodriguez R, Hansen M, Gabayan V, Ginzburg
Y, et al. High-throughput matrix-assisted laser desorption ionization-time-of-flight mass spectrometry method for quantification of
hepcidin in human urine. Hepcidin in human iron disorders: therapeutic
implications. Loss of
matriptase-2 activity results in an inability to reduce hepcidin
synthesis during iron deficiency (49). Ferroportin disease: a systematic meta-analysis
of clinical and molecular findings. Quality control based on
isotopic distributions for high-throughput MALDI-TOF and MALDI-FTICR
serum peptide profiling. A dual-monoclonal sandwich ELISA specific for
hepcidin-25. Induction of erythropoiesis and iron utilization by the HIF
prolyl hydroxylase inhibitor FG-4592 [Abstract]. have been reported to (partially) increase
hemoglobin and mean cell volume (119, 120, 148-151). Blood 2008;111:2392-9.
(78.) van Deuren M, Kroot JJ, Swinkels DW. Haematologica
2010;96:500-6.
(25.) Kulaksiz H, Theilig F, Bachmann S, Gehrke SG, Rost D,
Janetzko A, et al. Another
potential drawback of urine hepcidin measurements is its sensitivity to
oxidation (30) and the relatively high concentration of the smaller
hepcidin isoforms, which cannot be distinguished from hepcidin-25 by
most immunoassays. The STARD initiative and the reporting of studies
of diagnostic accuracy. Serum hepcidin but not prohepcidin may be an effective marker for
anemia of inflammation (AI). These extracellular signaling molecules act on
hepatocellular BMP receptors to activate the intracellular SMAD signaling pathway and increase hepcidin transcription. Annu Rev Pathol 2009;4: 489-515.
(165.) Sasu BJ, Li H, Rose MJ, Arvedson TL, Doellgast G, Molineux
G. Hepcidin antagonists, on the
other hand, might be expected to benefit patients with diseases of
hepcidin excess manifested as iron-restricted anemia and systemic iron
deficiency, such as iron-refractory IDA, ACD (rheumatic diseases,
inflammatory bowel diseases, autoimmune diseases), CKD, multiple myeloma
and other cancers, obesity-related iron deficiency, and cardiovascular
disease.
STRENGTHS AND LIMITATIONS OF QUANTITATIVE PLASMA AND URINE HEPCIDIN
ASSAYS
Table 1. Moreover, well-designed large
clinical studies addressing safety and long-term efficacy are needed to
clarify the risks and benefits of hepcidin-targeted treatments.
(198.) Peeling P, Dawson B, Goodman C, Landers G, Trinder D.
Athletic induced iron deficiency: new insights into the role of
inflammation, cytokines and hormones. Although the physiological relevance of GDF15 and TWSG1 remains
to be defined, these proteins might have therapeutic potential. Biochem J 2010;431:363-71.
(33.) Sumboonnanonda A, Malasit P, Tanphaichitr VS, Ong-ajyooth S,
Sunthornchart S, Pattanakitsakul S. Nat Genet
2004;36:481-5.
(27.) Isoda M, Hanawa H, Watanabe R, Yoshida T, Toba K, Yoshida K,
et al. Rapid Commun Mass Spectrom 2010;24:1251-9.
(120.) Tchou I, Diepold M, Pilotto PA, Swinkels D, Neerman-Arbez M,
Beris P. This stress response can be controlled by the transcription
factor cAMP-response-element-binding-protein-H (67) or by the
stress-inducible transcription factors CCAAT-enhancer-binding protein
(C/EBP[alpha]) and C/EBP-homologous protein (68). Growth differentiation factor 15 in patients with
congenital dyserythropoietic anaemia (CDA) type II. Two to
tango: regulation of Mammalian iron metabolism. Obesity (Silver Spring)
2010;18:1449-56.
Recent studies have demonstrated hepcidin expression by cells other
than hepatocytes, although at much lower levels by comparison. Studies to assess the
role of hepcidin in ACD are complicated by the lack of a gold standard
methodology. These observations raise
the possibility that hepcidin may prove to be a novel determinant for
cardiovascular disease risk.
(59.) Nemeth E, Rivera S, Gabayan V, Keller C, Taudorf S, Pedersen
BK, Ganz T. Through an autocrine interaction with ferroportin, local hepcidin may protect the nearby
cells from iron deficiency, prevent extracellular oxidative stress,
affect inflammatory reponses, and/or deplete extracellular iron pools
that are available for extracellular pathogens (27, 40-42). J Clin Invest
2002;110:1037-44.
(54.) Pak M, Lopez MA, Gabayan V, Ganz T, Rivera S. Biochimie
2009;91:1223-8.
(168.) Zaritsky JJ, Young BY. Posttranslational processing of hepcidin
in human hepatocytes is mediated by the prohormone convertase furin.
Blood Cells Mol Dis 2008;40:132-8.
(152.) Oppenheimer SJ. It exerts its regulatory function
by counteracting the function of ferroportin, the major cellular iron
exporter in the membrane of macrophages, hepatocytes, and the
basolateral site of enterocytes. Blunted hepcidin response to oral iron challenge in
HFE-related hemochromatosis. Accordingly, patients have
increased innate hepcidin concentrations resulting in extremely low
transferrin saturation percentages and ferritin concentrations in the
lower range of the reference interval (118, 119, 120, 148-151).
Therefore, assessment of hepcidin concentrations can serve to exclude or
raise the suspicion for matriptase-2 deficiency in unexplained IDA and
thus help to avoid the unnecessary burden associated with multiple
diagnostic testing and delayed or ineffective treatment.
(21.) Bekri S, Gual P, Anty R, Luciani N, Dahman M, Ramesh B, et
al. Mutations in TMPRSS6 cause iron-refractory iron
deficiency anemia (IRIDA). In addition, the lower hepcidin concentrations observed
in response to hypoxia may be attributed to liver-specific stabilization
of hypoxia-inducible factor (HIF)-1 (60), with downstream effects on the
BMP/ SMAD signaling pathway (61, 62). Moreover, there is a need for harmonization of the various
assays to enable the establishment of world-wide reference intervals and
clinical decision limits. We furthermore summarize human studies of hepcidin in
physiological and pathophysiological states, and discuss the evidence of
the therapeutic potential of modulating hepcidin concentrations. These routes
comprise 4 highly interconnected regulatory pathways (Fig. This observation draws
further attention to the concern that lowering hepcidin concentrations
by phlebotomy in HH patients may exacerbate the underlying
pathophysiology, exacerbating the excess release of iron into the
circulation, with an ensuing vicious circle that leads to the need for
more frequent maintenance phlebotomies in HH patients (125, 126).
In a study among anemic cancer patients receiving ESA therapy,
those with relatively low hepcidin concentrations at baseline showed a
better response (197). Swinkels, NOXXON, Pharma AG,
Berlin, Germany; Pieris AG, Freising-Weihenstephan, Germany.
(134.) Kattamis A, Papassotiriou I, Palaiologou D, Apostolakou F,
Galani A, Ladis V, et al. J Clin Oncol 2010;28:2538-43.
The wide reference intervals may be attributed at least partly to
the increase of hepcidin concentrations in the course of the day (12,
29, 96, 97, 107). Regulation of iron homeostasis by the
hypoxiainducible transcription factors (HIFs). J Clin Invest 2010;120:4466-77.
(56.) Tanno T, Porayette P, Sripichai O, Noh SJ, By rnes C,
Bhupatiraju A, et al. Serum
hepcidin-25 may replace the ferritin index in the Thomas plot in
assessing iron status in auto repair anemic patients. To the best of our knowledge there are 2 reported
studies of hepcidin concentrations in pregnant women, both of which
showed that hepcidin concentrations in anemic pregnant women is lower
than in nonanemic pregnant women, but are not related to cord-blood or
newborn hepcidin or other fetal iron parameters (114, 121).
(149.) Melis MA, Cau M, Congiu R, Sole G, Barella S, Cao A, et al.
A mutation in the TMPRSS6 gene, encoding a transmembrane serine protease
that suppresses hepcidin production, in familial iron deficiency anemia
refractory to oral iron. Second, increased hepcidin
activity postexercise may reduce the absorption of iron from the diet
(203). et al. Potential conflicts of interest:
(223.) Janssen MC, Swinkels DW. Br J Haematol 2010; 149:322-33.
(31.) Ashby DR, Gale DP, Busbridge M, Murphy KG, Duncan ND, Cairns
TD, et al. Modelling of a metal-containing
hepcidin. J Hepatol
2008;49:123-33.
(166.) Swinkels DW, Wetzels JF. Whether binding to these carrier molecules influences the
functional properties of hepcidin is uncertain.
Small and large studies of healthy controls have revealed
considerable interindividual variation in hepcidin concentrations,
resulting in wide reference intervals (12, 29, 96, 97, 107, 109)