Repair of the damaged heart

The human heart contains a subpopulation of replicating myocytes that is enhanced in pathologic states characterized by acute and chronic cardiac failure. In accordance with our hypothesis that these dividing cells represent amplifying myocytes originated from a pool of undifferentiated cells, effort was made to establish the conditions for the isolation and expansion of potential progenitor cells from small samples of human myocardium. Here we report the identification of a c-kit-positive cardiac stem cell that is self-renewing, clonogenic, and multipotent. This primitive cell has the morphologic properties and expresses some of the surface antigens commonly found in mesenchymal stem cells. Additionally, when locally injected in the infarcted myocardium of immunodeficient rats and mice, cardiac stem cells regenerate myocytes and coronary vessels