Cardiac versus non-cardiac stem cells to repair the heart: The role of autocrine/paracrine signals

The heart can grow and change to accommodate alterations in its workload in response to stress. Stress-induced pathological cardiac hypertrophy, characterized by an increase in the size of cardiac myocytes, is a major risk factor for the development of cardiomyopathies and heart failure. Restoration of damaged heart muscle through repair or regeneration is a promising strategy to cure cardiovascular diseases. The robust proliferative and differentiation capacity of stem cells holds the potential of an unlimited supply of functioning cardiomyocytes. A crucial issue in designing rational stem cell-based therapy approaches for cardiac diseases is the understanding of the exact mechanisms whereby each stem cell can affect the performance of the heart. Stem cells are self-renewing and can become functionally specialized cardiac cells with the proper milieu of locally acting growth and signaling factors. In this chapter, we review the current advancements in our understanding of how adult stem cells within the myocardium, such as cardiac stem cells, or derived from other tissues, such as mesenchymal stem cells, may contribute to the repair of the damaged heart. Moreover we describe how this process could be experimentally boosted for therapy, by manipulating local autocrine and paracrine molecules regulating endogenous stem cell regenerative potential.