Heart repair: from natural mechanisms of cardiomyocyte production to the design of new cardiac therapies.

Most organs in mammals, including the heart, show a certain level of plasticity and repair ability during gestation. This plasticity is, however, compromised for many organs in adulthood, resulting in the inability to repair organ injury, including heart damage produced by acute or chronic ischemic conditions. In contrast, lower vertebrates, such as fish or amphibians, retain a striking regenerative ability during their entire life, being able to repair heart injuries. There is a great interest in understanding both the mechanisms that allow heart plasticity during mammalian fetal life and those that permit adult cardiac regeneration in zebrafish. Here, we revise strategies for cardiomyocyte production during development and in response to injury and discuss differential regeneration ability of teleosts and mammals. Understanding these mechanisms may allow establishing alternative therapeutic approaches to cope with heart failure in humans.