Stem cells in the treatment of heart disease.

Progenitor cells residing in bone marrow, adipose tissue, and skeletal muscle or circulating in the blood are capable of improving myocardial function in preclinical models. In contrast, early clinical studies using bone marrow cells have shown mixed results and reflect our incomplete understanding of underlying mechanisms. Recent identification of various cardiac precursor cells has suggested an endogenous reservoir for cell-based repair. However, confronted with massive cardiac cell loss, inventive strategies and enabling technologies are required to mobilize or deliver functionally competent progenitor cells to sites of injury or to effectively stimulate endogenous repair. We review our present knowledge in this promising and rapidly evolving development in cardiovascular medicine and highlight obstacles as well as opportunities.