| Treatment of acute myocardial infarction (AMI) with endothelial progenitor cell (EPC) therapy has been shown to lead to improved cardiac function. However, effect of post-MI cell injection timing on cardiac retention of cells and functional benefit remains largely uncharacterized.; Male, bone marrow-derived EPCs were injected into the peri-infarct myocardial region of female rats after coronary artery ligation. Post-MI injection time points tested were 1 hour and 3, 7, 21, 35 days. Organs were harvested at 7 days post-injection (PI) for cell retention assessment using real-time quantitative PCR for the Sry3 gene on the Y chromosome. Left ventricular (LV) cell retention was maximal for the 7 day post-MI injection group. Both early (1 hour, 3 day) and late injection (21, 35 day post-MI) rendered comparatively minimal LV cell retention. There was rapid cell loss from cardiac injection site and accumulation in the lungs. Functional cardiac assessment at 7 days PI showed cardiac benefit only with cell injection at 7 days post-MI.; These results indicate injection time point post-MI is critical to maximizing both cell retention and cardiac benefit within the heart. |
