Ascorbic acid improves embryonic cardiomyoblast cell survival and promotes vascularization in potential myocardial grafts in vivo

Organ restoration via cell therapy and tissue transplantation is limited by impaired graft survival. We tested the hypothesis that ascorbic acid (AA) reduces cell death in myocardial grafts both in vitro and in vivo and introduced a new model of autologous graft vascularization for later transplantation. Luciferase (Fluc)- and green fluorescent protein (GFP)-expressing H9C2 cardiomyoblasts were seeded in gelatin scaffolds to form myocardial artificial grafts (MAGs). MAGs were supplemented with AA (5 or 50μmol/L) or plain growth medium. Bioluminescence imaging showed increased cell photon emission from day 1 to 5 in grafts supplemented with 5μmol/L (p<0.001) and 50μmol/L (p<0.01) AA. The amount of apoptotic cells in plain MAGs was significantly higher than in AA-enriched grafts. In our in vitro model, AA also enhanced H9C2 cell myogenic differentiation. For in vivo studies, MAGs containing H9C2-GFP-Fluc cells and enriched with AA (n=10) or phosphate-buffered saline (n=10) were implanted in the renal pouch of Wistar rats. At day 6, postimplantation bioluminescence signals decreased by 74% of baseline in plain MAGs versus 36% in AA-enriched MAGs (p<0.0001). AA grafts contained significantly higher amounts of blood vessels, GFP⁺ donor cells, and endothelial cells. In this study, we identified AA as a potent supplement that improves cardiomyoblast survival and promotes neovascularization in bioartificial grafts.