This study investigates the potential of adult stem cells to regenerate ischemic cardiac muscle and vascular endothelium. The researchers transplanted highly enriched hematopoietic stem cells, known as side population (SP) cells, into lethally irradiated mice that were then subjected to ischemia by coronary artery occlusion followed by reperfusion. The SP cells, characterized by their CD34-/low, c-Kit+, and Sca-1+ surface markers, migrated into the ischemic cardiac muscle and blood vessels, differentiated into cardiomyocytes and endothelial cells, and contributed to the formation of functional tissue. Donor-derived cardiomyocytes were found primarily in the peri-infarct region, while donor-derived endothelial cells were identified in small vessels adjacent to the infarct. The results demonstrate the cardiomyogenic potential of hematopoietic stem cells and suggest a therapeutic strategy for myocardial infarction.This study investigates the potential of adult stem cells to regenerate ischemic cardiac muscle and vascular endothelium. The researchers transplanted highly enriched hematopoietic stem cells, known as side population (SP) cells, into lethally irradiated mice that were then subjected to ischemia by coronary artery occlusion followed by reperfusion. The SP cells, characterized by their CD34-/low, c-Kit+, and Sca-1+ surface markers, migrated into the ischemic cardiac muscle and blood vessels, differentiated into cardiomyocytes and endothelial cells, and contributed to the formation of functional tissue. Donor-derived cardiomyocytes were found primarily in the peri-infarct region, while donor-derived endothelial cells were identified in small vessels adjacent to the infarct. The results demonstrate the cardiomyogenic potential of hematopoietic stem cells and suggest a therapeutic strategy for myocardial infarction.