A MODEL OF CARDIAC REGENERATION AND LONG TERM CULTURE OF CARDIAC-DERIVED CELLS IN ZEBRAFISH

Zebrafish hearts can regenerate through activation of growth factors and trans-differentiation of fibroblasts, epicardial, myocardial and endocardial cells1,2,3, all positive for GATA4 during the process4,5. A innovative model of regeneration of the whole heart and the regenerating cells in ex-vivo culture is developed by a stimulation of cocktail of growth factors. In ex-vivo growth-factors-supplemented culture the heart regeneration was quite complete without signs of fibrosis. Epicardial- and endocardial-derived cells have shown capability to moving out of the herats in culture and were analysed and than expanded to obtain long term culture. Electron microscopy evidencing two main types of : 1) larger/prismatic and 2) small/rounded. Type(1) showed on the surface protein-sculptures, while type(2) was smooth with sparse globular proteins. To confirm their nature we have contemporarily analysed their proliferative capability and markers-positivity. The cells treated by growth factors have at least two-fold more proliferation with GATA4-positivity. The type (1) cell evidenced WT1+ (marker of embryonic epicardium); the type (2) showed NFTA2+(marker of embryonic endocardium); whereas cTNT-cardiotroponin (marker of cardiomyocytes) was negative. Under growth factors stimulation, GATA4+/WT1+ and GATA4+/NFTA2+ could be suitable candidates to be the cells with capability to move in/out of the tissue, probably by using their integrins..The model of regeneration in ex-vivo open the possibility to have long term selected organ/culture to future translationa studies.