Early haemoglobin-independent increase of plasma erythropoietin levels in patients with acute myocardial infarction

Aims: We studied plasma erythropoietin (EPO) levels and their relation with CD34+VEGFR-2+ (mature and progenitor endothelial cells) and CD34+ CD133+VEGFR-2+, or CD34+ CD117+VEGFR-2+ (early/immature endothelial progenitors) cells in patients with acute myocardial infarction (AMI). Methods and results: Fifty AMI patients undergoing percutaneous coronary intervention (PCI) within 6 h of symptom onset were enrolled. EPO, measured by ELISA, and cell subsets, by cytofluorimetric analysis, were evaluated before PCI, 24 h and 7 days afterwards. Forty-five healthy subjects (CTRLs) were studied. Plasma EPO levels were higher in AMI patients at admission, 24 h, and 7 days (P = 0.04, P = 0.0001, P = 0.001, respectively) than in CTRLs. No correlation was evidenced between EPO and haemoglobin (Hb) or haematocrit at admission or 24 h after AMI. Differently, both Hb and haematocrit inversely correlated with EPO at day 7 (P = 0.0016, P = 0.029, respectively). Plasma EPO levels correlated with CD34 +CD133+VEGFR-2+ cells at day 7 (P = 0.03). Conclusion: AMI patients have increased plasma EPO levels until day 7. In the early phase, plasma EPO levels are Hb-independent; at day 7, an Hb-modulated increase of EPO correlates with the percentage of CD34+CD133 +VEGFR-2+ cells.