The long-term effect of autologous endothelial progenitor cells from peripheral blood implantation on infarcted myocardial contractile force.

This study was designed to evaluate the long-term effect of endothelial progenitor cell (EPC) implantation in acute myocardial infarction in Sprague-Dawley rats after ligation of the left anterior descending coronary artery. Autologous EPCs from peripheral blood were purified and implanted into an acute myocardial infarct site. Specimens and muscle strip were harvested at 3 and 6 weeks, and at 6, 8 and 12 months for contractile force assessment and, by immunohistology, for expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and factor VIII. Expression of VEGF and bFGF, and microvessel counts and contractile force in the cell implantation group were significantly higher than in the control group up to 8 months after implantation. Beyond 8 months following implantation, however, no further improvement occurred. The EPCs showed an ability to improve contractile performance in infarcted myocardium by means of angiogenesis and vasculogenesis, and the results seemed to persist long-term.