Young at heart. An update on cardiac regeneration.

Cardiovascular disease remains one of the most important causes of mortality. Over the past decades important advances have been made in prevention and treatment of acute complications after myocardial infarction (MI). As a result, the number of patients that acutely die from MI has been reduced. Current treatments can not prevent the loss of cardiac contractility caused by cardiomyocyte death, and therefore patients that do survive MI are prone to develop progressive impaired cardiac function, which may lead to heart failure. Cell-based therapy has been proposed as a potential new therapy to prevent progression to end-stage heart failure by (re)generating contractile tissue in the damaged heart. During the last years many different cell sources have been studied extensively for their cardiomyogenic differentiation capacity in vitro and in vitro. These cells include several populations of cardiac-derived progenitor cells as well as mesenchymal stem cells derived from different sources. It has become clear that not only the origin, but also the "age" of a cell is an important determinant of its plasticity. Therefore, special attention is paid to the difference in developmental state of the cell sources and the consequences for their differentiation capacity and therapeutic applicability. Furthermore, we provide future perspectives for several aspects of cell-based therapy that could be optimized in order to enhance the regeneration of the heart.