Meeting Abstract

78.3  Wednesday, Jan. 6  Models of Cardiac Repair and Regeneration in Teleost Fish LAFONTANT, P.J.*; GRIVAS, J.A.; GOLDEN, B.L.; LESCH, M.A; FROUNTFELTER, T.; DePauw University; DePauw University; DePauw University; DePauw University; DePauw University pascallafontant@depauw.edu

The limited ability of mammalian adult cardiac myocytes to proliferate often results in scaring and permanent loss of cardiac function after injury. By contrast, in models including newt and axolotl, the destruction or resection of ventricular tissue is mitigated by partial to complete replacement of the lost tissue and the restoration of functional contractile myocardium; regeneration occurs with little to no scarring. More recently, robust regeneration has been demonstrated in the teleost zebrafish (Danio rerio). We developed a cardiac ventricular injury model in Goldfish and Giant danio to test whether the ability to repair and regenerate is widely distributed among teleosts. Following partial cauterization of their ventricles, we observed three distinct and temporally overlapping processes occurring. The first phase is an intense inflammatory response, characterized by increased presence of myeloperoxidase-positive cells. The inflammatory cells were also observed by electron microscopy. A second phase involves tissue remodeling with differential accumulation of collagen in the two species and the presence of PCNA-positive cells. The third phase involves the resorption of necrotic tissue and of accumulated collagen, and is accompanied by apparent regeneration of the injured ventricle by 45 days. Our data suggests that the ability to regenerate heart tissue may extend beyond the teleost zebrafish, and that the Goldfish and Giant danio can be used as models of heart repair and regeneration.