Cardiac repair represents a feasible goal by means of cell therapy. Thus, the hypothesis was advanced that primitive cells can be isolated and expanded from the human and murine heart. For this purpose, myectomies from 22 patients undergoing aortic valve replacement and 10 hearts from each J129sv mice and Wistar Rats were sampled. Human cells were obtained by the tissue explant technique whereas mouse cells were isolated after enzymatic dissociation. Culture conditions were established minimizing the use of serum. Doubling time averaged 26 12 hours without significant decrement in cell replication until P10. Small c-kit^pos and/or Sca-1^pos cells were present in human and mouse preparations at an incidence of 1.06 0.01% and 2.05 1.45%, respectively, among which nearly 80% expressed GATA-4 or Mef-2C. Vasculogenic progenitors (Flk1^pos), constituted 2% of the cells. Vimentin (65%) and a-smooth muscle actin (7%) were detected, whereas vW factor (FVIII) and a-sarcomeric actin (a-Sarc) involved 11 6% and 1.3 0.6% of the cells, respectively. Interestingly, a significant fraction of cultured cells showed the morphology of Purkinje cells and expressed HNK1. Upon differentiating medium, cells labelled by SMA, FVIII and a-Sarc markedly increased. After injection of human and murine cells in the border zone of an experimental infarct, a partial functional and structural recovery was observed.

Conclusion: 

stem/progenitor cells are present in the mammalian heart representing a suitable autologous source to repair the damage myocardium by cellular therapy.