Novel Circulating Isoforms of Hepcidin

Abstract

To the Editor: The 25 amino acids constituting peptide hepcidin-25 (Hep25)1 are key regulators of iron metabolism (1). Two isoforms with 20 (Hep20) and 22 (Hep22) amino acids have been found in urine, whereas Hep20 has been detected in blood (2) and serum (3). Increased concentrations of Hep25 are observed in chronic kidney disease (1). We used liquid chromatography–high-resolution mass spectrometry (LC-HRMS) to analyze plasma samples from patients with postoperative infections after gastrointestinal surgery. Analysis of these samples revealed high concentrations of C-reactive protein and several putative hepcidin isoforms. To the best of our knowledge, some of these hepcidin isoforms have not previously been reported. Blood samples obtained by venipuncture and collected into lithium-heparin tubes were maintained at room temperature for 30 min and centrifuged at 1500 g for 15 min at 4 °C, and then the plasma was transferred in 300-μL aliquots into 2-mL polypropylene tubes and stored at −80 °C until analysis. Written consent was obtained from the patients (n = 5) whose results are included in the present work. The samples were processed according …