Potential contribution of the hepcidin-macrophage axis to plaque vulnerability in acute myocardial infarction in human

Objectives: Hepcidin-25 serves as a key peptide in the regulation of iron homeostasis and inflammation. It remains unknown whether hepcidin-25 plays an adverse role in atherosclerotic diseases. The aim of this study was to investigate whether hepcidin-25 is involved in the pathophysiology of coronary plaque vulnerability.

Methods and results: Serum hepcidin-25 levels were quantitatively determined by the LC-MS/MS assay system. Peripheral blood was collected from patients with acute myocardial infarction (MI, n=33) and patients with stable angina pectoris (sCAD, n=19). The levels of hepcidin-25, IL-6, and CRP were significantly higher in the patients with acute MI than in the patients with sCAD. Coronary blood was aspirated from the culprit arteries via a thrombectomy catheter in 16 of the MI patients. Serum from the aspirates contained higher levels of hepcidin-25 and IL-6 compared with the peripheral blood. In immunohistochemical staining, the macrophages of the plaques in the solid component of the aspirates were immunoreactive for hepcidin-25. To confirm the clinical observation, an in vitro study was performed using human macrophages and coronary endothelial cells. The hepcidin gene and protein were detected in the cultured macrophages but not in the endothelial cells. Hepcidin-25 exposure induced ferroportin degradation and reduced the survival rate of endothelial cells.

Conclusions: The results of the present study demonstrated that circulating hepcidin-25 and IL-6 were both elevated in the acute phase of MI and that hepcidin-25 released from plaque macrophages and other cell sources contributed to the plaque instability by inducing endothelial cell death.