Cardiac regenerative capacity of the American alligator (87.5)

Abstract

Human hearts lack regenerative capacity and form scars after myocardial infarction. While teleost fish and urodele amphibians are able replace lost or damaged cardiomyocytes even as adults, mice are only able do so as neonates. Whether regenerative capacity exists in other vertebrate clades (reptiles and birds) has not yet been described. In order to determine if reptile hearts have regenerative potential following tissue damage, we developed injury models similar to those used in zebrafish and mice—ventricular resection and cryoinjury—and tested them in a non‐traditional animal model, the American alligator.Hatchling alligators were injured or sham operated, and allowed to recover over periods of time up to 4 months. Preliminary data from hatchlings 1, 3, and 14 days post‐injury show appearance of regenerative cardiomyocytes around the injury area. Whether this is a significant increase over background proliferation of sham operated hearts, as well as the ability to replace scar tissue with cardiomyocytes, remains to be determined. Results from this study will demonstrate whether the alligator— with its four‐chambered heart, and independent systemic and pulmonary pressure generation—can be a useful model in studies of cardiac regeneration, and serve to further elucidate the phylogenetic and evolutionary relationship between the aforementioned clades with regard to regenerative capacity.Grant Funding Source: Supported by California Institute for Regenerative Medicine