Association of prohepcidin and hepcidin-25 with erythropoietin response and ferritin in hemodialysis patients

Hepcidin is a key regulator of iron metabolism. In this study, we examined whether measurement of hepcidin is useful in assessing recombinant human erythropoietin (rHuEPO) responsiveness in regular hemodialysis (HD) patients in a cross-sectional fashion. We examined the association between serum prohepcidin, a prohormone of hepcidin, and rHuEPO dosage and the rHuEPO/hemoglobin (Hb) ratio in 75 HD patients. We also semiquantatively measured the peak intensity of serum hepcidin-25, the major form of mature hepcidin, in 24 HD patients by using surface-enhanced laser desorption ionization time of flight time mass spectrometry, and compared those between rHuEPO-hyporesponsive (rHuEPO 192 +/- 10 [126-252] IU/kg/week, n = 15) and responsive patients (rHuEPO 40 +/- 9 [0-81] U/kg/week, n = 9). A significant but weak relationship was found between serum prohepcidin and rHuEPO dosage (r = 0.24, p < 0.05) and rHuEPO/Hb ratio (r = 0.22, p = 0.06). However, prohepcidin did not become an indicator of hematopoietic parameters by multiple regression analysis. Serum hepcidin-25 intensity was significantly and positively correlated with ferritin (r = 0.51, p < 0.01) but not with log-transformed C-reactive protein. There was no difference in the intensities of serum hepcidin-25 between rHuEPO-hyporesponsive and responsive patients (64 +/- 10 vs. 52 +/- 16 AU, p = NS). It follows from these findings that the assessment of serum hepcidin using currently available assays was not valid in predicting rHuEPO responsiveness in chronic HD patients.