Cell sources for cardiovascular tissue regeneration and engineering.

The heart has long been regarded as a post-mitotic organ. Since many years, physicians have focused on developing strategies to restore the myocardium after ischemic damage followed by ventricular dysfunction. Restoration is generally achieved through the redirection of blood flow or by supporting contractile performance. The discovery of stem cells capable of generating angiogenic or contractile cells and structures offers new horizons to patients suffering from myocardial disease. Experimental studies indicate that the delivery or mobilization of stem and progenitor cells may improve tissue perfusion and the contractile performance of the damaged heart. Another aspect of restoration is based on cardiovascular tissue engineering and the creation of three-dimensional biological conformations to replace the artificial materials frequently used during operations, i.e., valves and grafts, or even a portion of the nonfunctional myocardial tissue. At present, the underlying intra- and intercellular molecular mechanisms controlling myocardiogenesis and cardiomyocyte replacement during regenerative processes are not very well understood. In this brief review we try to give the answers to questions on certain aspects of myocardial tissue regeneration and engineering procedures.