Hepcidin regulates iron metabolism by inhibiting intestinal iron absorption and iron release from iron stores. In addition to iron overload, inflammatory conditions also up-regulate hepcidin synthesis, which may serve as an antimicrobial defense by reducing iron availability to the invading microbes. The purpose of this study is to test this hypothesis in human patients by determining serum hepcidin concentration by enzyme linked immunosorbent assay (ELISA) in healthy blood donors (n = 60) and patients hospitalized because of bacteremia (n = 50), before (day 0) and after seven days (day 7) of appropriate antibiotic treatment. Serum hepcidin was significantly increased in patients with bacteremia, both at day 0 and at day 7, compared to healthy controls. However, there was significant reduction of serum hepcidin after 7-day treatment, in concert with changes in serum C-reactive protein (CRP). The hepcidin changes were similar for both Gram-negative and Gram-positive single infection cases, while CRP was significantly reduced only in the former. In contrast to hepcidin, the levels of serum ferritin in the patients remained high after treatment, irrespective of infection type. These data confirm the stimulation of hepcidin secretion in human subjects upon different types of systemic microbial infection and suggest that hepcidin is a more sensitive and treatment-responsive acute-phase marker than ferritin in bacteremia, which needs to be explored with bigger-sized and better-matched patient cohorts.
Keywords: CRP; acute phase marker; bacteremia; ferritin; hepcidin.