Hepcidin levels in chronic hemodialysis patients: a critical evaluation

Altered systemic iron metabolism is a key element of uremia, and functional iron deficiency mainly related to subclinical inflammation makes it difficult to maintain proper control of anemia in chronic hemodialysis patients (CHD). In the last decade, the hepatic hormone hepcidin has been progressively recognized as the master regulator of circulating iron levels through the modulation of cellular iron fluxes in response to iron stores, as well as to erythroid and inflammatory stimuli. Hepcidin is cleared by the kidney and progression of renal disease has been associated to increased serum hepcidin levels. This, in turn, reduces iron availability for erythropoiesis, suggesting anti-hepcidin strategies for improving anemia control. Moreover, hepcidin has been recently implicated in the pathogenesis of long-term complications of dialysis, like accelerated atherosclerosis. Initial studies almost invariably reported a sustained increase of serum hepcidin in chronic hemodialysis patients. Noteworthy, such studies included relatively few patients and controls that were poorly matched for major determinants of serum hepcidin at population level, i.e., age and gender. More recent data based on accurately matched larger series challenge the view that hepcidin is intrinsically increased in hemodialysis patients, showing a marked inter- and intra-individual variability of hormone levels. Here we take a critical look to the data published so far on hepcidin levels in CHD, analyze the reasons underlying the discrepancies in available studies and the hepcidin variability in CHD, and point out the need for further studies in large series of well-characterized CHD patients and controls.