Empowering Adult Stem Cells for Myocardial Regeneration V2.0

Myocardial aging is a constellation of concurrent processes occurring at organ, cellular, and molecular levels. Despite this complexity, differences become readily identifiable by comparing phenotypic characteristics of mammalian cardiomyocytes and cardiac stem cells in young versus old hearts. One hallmark unique to the early postnatal myocardium is increased cellular proliferation, resulting in formation of new myocytes. Although research is ongoing to identify when proliferation subsides in the postnatal myocardium, current findings indicate that the murine heart experiences a proliferative burst around 2 weeks, whereas the human heart experiences proliferation in smaller growth spurts throughout adolescence. It is hypothesized that the regenerative capacity of the neonatal mammalian heart is dependent on the sympathetic nerve, and poorly functioning nerve structure in adult myocardium impairs the heart’s capability to regenerate. Later in life, de novo myocyte formation in mammals is severely limited by the suboptimal milieu of struggling myocardium and accumulation of poorly functioning senescent myocytes. Senescence also exacts a toll on the cardiac stem Review