L emos AR et AL .596Rev Assoc Med Bras 2010; 56(5): 596-9I ntroductIonHepcidin and iron metabolismIron is an essential element for nearly all living organisms. Iron is a key component of oxygen storage and transporting proteins, such as hemoglobin and myoglobin, and of many enzymes that catalyze oxidation-reduction reactions necessary to generate energy and produce various metabolic intermediates for host defense 1-3 .In all species, the concentration of iron in biological fluids is tightly regulated to provide iron as needed and to avoid toxicity, since iron excess can lead to the generation of reactive oxygen species (ROS), and decreased iron levels can lead to anemia 4,5 . Thus, maintenance of body iron stores is essential, because many human diets contain iron sufficient only to replace the small iron losses. When iron intake is more abundant, apparently iron absorption is appropriately controlled 6,7 .Iron deficiency may occur by inadequate dietary intake, by increased physiological needs of the nutrient, and/or by increased losses, which may lead to anemiaAnemia is the most widespread nutritional disorder in the world, affecting mainly women of childbearing age and children under two years of age 8 . The same scenario is described in Brazilian studies 9-12 . Data from the last National Survey on Children and Women Health revealed that 20.9% of Brazilian children and 29.4% of women have anemia 13 .For this reason, there is great interest in investigating effective methods for the diagnosis of iron deficiency anemia.Recent studies have evaluated the use of hepcidin as a biomarker for the regulation of iron metabolism. Hepcidin has evolved as the primary regulator of iron homeostasis and a probable mediator of anemia of chronic disease and inflamma-tion. This role has been widely demonstrated in a number of recent studies 14-18 , and there is enormous interest in quantifying circulating hepcidin levels in clinical samples 19 .*Correspondence: Avenida Dr. Arnaldo 715 - Cerqueira CésarSão Paulo – SPCEP: 01246-904AbstractIron deficiency anemia is the most prevalent nutritional disorder in the world. Information on the metabolism of hepcidin and its possible significance as a biochemical parameter in iron deficiency anemia is reported in this review, which was based on a survey of the databases PubMed and LILACS for articles published between 2006 and 2010 on hepcidin as a biomarker for the regulation of iron metabolism. The literature search returned 35 studies published in international journals and one study on the subject in a Brazilian journal. Hepcidin production is homeostatically regulated by anemia and hypoxia. When oxygen delivery is inadequate, hepcidin levels decrease. Consequently, more iron is made available from the diet and from the storage pool in macrophages and hepatocytes. Hepcidin binds to ferroportin, regulating iron release into plasma. When hepcidin concentrations are low, ferroportin molecules are displayed on the plasma membrane and release iron. When hepcidin levels increase, hepcidin binds to ferroportin molecules inducing their internalization and degradation, and iron release is decreased progressively. Apparently, the development of diagnosis and therapy for anemia based on the bioindicator hepcidin may provide a more effective approach. Epidemiological studies are needed to demonstrate the relevance of hepcidin to the differential diagnosis of anemia, including sampling protocols for analysis, with standardization similar to that used in other biochemical assessments, and establishment of cutoff points for urinary and plasma expression of this peptide. K ey woRds : A nemiA . i Ron . P ARAmeteRs .hepcIdIn as a bIochemIcal parameter for the assessment of Iron defIcIency anemIaa ndrea dos r eIs l emos 1 , l orene a parecIda s Ilva I smael 1 , c laudIa c arvalho m altese b oato 2 , m arIa t ereza f rota b orges 3 , p atrIcIa h elen de c arvalho r ondó 4*Study conducted at the Department of Nutrition, School of Public Health, Universidade de São Paulo, São Paulo, SP, Brazil.1. Graduação em Nutrição - Mestranda da Faculdade de Ciências Farmacêuticas da Universidade de São Paulo, São Paulo, SP 2. Mestranda da Faculdade de Saúde Pública da Universidade de São Paulo, São Paulo, SP.3. Mestre em Nutrição - Doutoranda na Faculdade de Saúde Pública da Universidade de São Paulo, São Paulo, SP4. Livre-docência - Professor Doutor do Departamento de Nutrição, Faculdade de Saúde Pública da Universidade de São Paulo, São Paulo, SPReview Article
