What regulates hepcidin in poly-transfused β-Thalassemia Major: erythroid drive or store drive?

Abstract

Hepcidin, a key regulator of iron homeostasis, is increased by iron overload and inflammation while suppressed by hypoxia. In spite of iron overload in β-Thalassemia Major (β-TM), a paradoxical decrease in hepcidin is observed. To assess the opposing effects of enhanced erythropoiesis due to anemia and iron overloading on hepcidin in β-TM patients. This prospective observational study was done at our tertiary care hospital. Eighty-three pediatric polytransfused (> 20 transfusions) patients of β-TM were compared with 70 children who served as controls. Serum assays for ferritin, transferrin receptors (sTfR) and hepcidin were performed. Independent Student t test was used to compare variables between both the groups. A Pearson correlation coefficient was used to find any correlation between ferritin, sTfR and hepcidin. The mean value of hepcidin in β-TM children was 13.88±10.68 ng/ml (range, 0.9-60 ng/ml) and showed significant negative correlation with sTfR (r = -0.296, P < 0.0066). However, there was no correlation of hepcidin with ferritin. Ferritin and sTfR were significantly elevated in β-TM children compared to controls (P < 0.001). The mean serum hepcidin/ferritin index in the study group (0.00552) was significantly lower (P value < 0.001) than the controls (0.378) thus indicating inappropriate levels of hepcidin to iron overload. In polytransfused β-TM children increased iron demand dominates over iron overload in regulating hepcidin. In spite of excessive iron load, the inappropriate hepcidin levels may further contribute to iron overload enhancing iron toxicity.