Neonatal Heart Regeneration: Mounting Support and Need for Technical Standards

R egenerating the adult heart is by many standards theholy grail of modern cardiovascular medicine. As a result, this field has been fraught with innumerable conflicts and controversies. Everything from the rate of cardiomyocyte turnover and regulators of cardiomyocyte proliferation in the adult heart, to the existence of cardiac progenitors and their therapeutic role, has been heavily contested. In 2011, we published a report outlining the regenerative potential of the neonatal mouse heart in the first few days of life. We found that the newborn mouse heart is capable of regeneration following apical resection of 15 % of the left ventricle with only minimal scarring seen in a small percent-age of samples. Moreover, we showed that this process is mediated primarily by proliferation of preexisting cardiomyo-cytes.1 These studies were inspired by the well-known ability of early neonatal myocytes to divide, even in culture. Ou