Abstract 15555: Administration of c-Kit+ Cardiac Stem Cells (CSCs) Results in Increased Proliferation and Cardiac Content of CSCs 1 Year Later

Background: We have previously shown in rats that the beneficial effects of c-kit+ CSCs on LV function and remodeling post-myocardial infarction persist for at least 1 year after CSC administration. However, in that study the retention of transplanted Y-chromosome+ cells in the risk region (RR) of female rat hearts at 1 year was low (<10% of total nuclei) and not sufficient to account for the functional improvement, suggesting that other mechanisms must be at work. Methods and Results: To address this issue, rats received intracoronary vehicle or 1x106 syngeneic CSCs 4 h after a 90-min coronary occlusion; 11 months later, BrdU treatment was given for 1 month. CSCs, which are c-kit+/CD45−, were distinguished from c-kit+ hematopoietic stem cells/mast cells, which are CD45+. At 1 year after CSC administration, the total number of c-kit+ or c-kit+/BrdU+ cells in the heart (the sum of c-kit+/CD45− and c-kit+/CD45+ cells) did not differ between CSC and control groups (Figs. H and I). However, CSC transplantatio...