For managing iron therapy in MHD patients being treated with ESA, it has been hypothesized that measuring serum levels of hepcidin may be useful as an additional selleck chemical tool for predicting and monitoring the need for iron supplementation.
However, the recent clinical observations demonstrated that it could not provide an advantage over established markers of iron status, ferritin and TSAT [47, 53]. Hepcidin and iron regulation in the intestine and macrophages As mentioned above, serum hepcidin levels were found to be tightly linked to circulating ferritin levels in both healthy volunteers and MHD patients [8, 45]. To estimate the relationship between serum hepcidin levels and iron absorption serum ferritin may be used as a surrogate for hepcidin, as depicted in Fig. 2a. A highly significant inverse correlation between iron stores, as reflected by serum ferritin, and the absorption of nonheme iron was consistently found in healthy subjects and MHD patients [54–57] (Fig. 2b). As the serum ferritin decreased with iron deficiency (<100 ng/ml), a 10-fold rise in nonheme iron absorption occurred . This indicates that depletion of body iron stores accelerates the dietary absorption mTOR kinase assay of non-heme iron . This effect is probably due to the control
of iron absorption by hepcidin. A similar relationship between body iron stores or serum ferritin levels and iron egress from macrophages has been observed . Hepcidin also appears to play a fundamental role in iron homeostasis in the RES. Iron recycles from senescent erythrocytes to macrophages and back to circulation (approximately 20–25 mg/day), resulting in an
iron supply to erythroid cells which is far greater than that provided by duodenal absorption (1–2 mg/day). Erythrocyte iron processing by the RES was studied after intravenous injection of 59Fe-labeled heat-damaged red blood cells and 55Fe-labeled Telomerase transferrin to calculate the early release of 59Fe by the RES . Interestingly, there was a significant negative correlation between the percentage of early iron release by macrophages and serum ferritin (Fig. 2c). This has led to the conclusion that storage iron tightly modulates the release of iron into the circulation from the intestine and from macrophages under the control of hepcidin. Recently, factors affecting erythrocyte iron incorporation were analyzed in anemic pediatric patients treated with oral iron. It was concluded that hepcidin powerfully controlled the utilization of dietary iron by erythrocytes, as serum hepcidin was inversely correlated with RBC iron incorporation .