Specifically, using models of chronic ischemic cardiomyopathy (old myocardial infarction [MI]), we found that three repeated doses of c-kit-positive cardiac cells (CPCs) in mice [7] and rats [8,9] and cardiac mesenchymal cells (CMCs) in mice [5] improve left ventricular (LV) function to a greater extent than a single dose; the fact that similar outcomes were observed with two different cell types and in two different species suggests that the greater efficacy of multiple doses is not dependent on species or cell type. This evidence concerns the gene KIT and myocardial infarction.