Expanded human cord blood-derived endothelial progenitor cells salvage infarcted myocardium in rats with acute myocardial infarction.

1. Cell transplantation has promise as a therapeutic option for restoring impaired heart function after acute myocardial infarction (AMI). However, the optimal cell type to use remains controversial. We investigated the therapeutic efficacy and feasibility of intramyocardial transplantation of human umbilical cord blood-derived endothelial progenitor cells (hUCB-EPC) in rats with AMI. 2. The Wistar rats myocardial infarction model was established by ligating the left anterior descending artery. The labelled hUCB-EPC were transplanted through intramyocardial injection. Left ventricular function was assessed using a pressure-volume catheter and echocardiogram. Anti-VIII immunohistochemistry staining was used to reflect the degree of angiogenesis in peri-infarcted areas by calculating the average capillary density. The fibrosis degree of infarcted myocardium was analysed by Masson staining and the collagen volume fraction was calculated. 3. The labelled donor endothelial progenitor cells were detected in the new microvessels in host myocardium by double-positive staining with CM-Dil and FITC-UEA-l. An increase in left ventricular ejection fraction, left ventricular fractional shortening, left ventricular end-systolic pressure, first derivative of left ventricular pressure (+dP/dtmax and -dP/dtmax), as well as a decrease in the left ventricular end-diastolic pressure in rats with cell therapy indicated a significant improvement in global heart function. The cell therapy group had increased microvessel formation and a decreased degree of myocardial fibrosis compared to the control group. Moreover, the degree of myocardial fibrosis was less than that of the control group. 4. The improved global heart function and decreased cardiac fibrosis in rats with AMI implies the potential benefit of hUCB-EPC transplantation.