MKI67 and myocardial infarction: To study the impact of hTERT + PDGFRα + cMSC treatment on cardiac cell proliferation after MI, we used Ki67 and WGA co-immunostaining to quantify the percentage of rat cardiomyocytes (CM) and non-cardiomyocytes actively proliferating 4 weeks after hTERT + PDGFRα + cMSC delivery.