Mesenchymal stromal cells improve cardiac function and left ventricular remodeling in a heart transplantation model

Background: Ischemia/reperfusion (I/R) injury is an inevitable consequence of organ transplantation and a major determinant of patient and graft survival in heart transplantation. Bone marrow–mesenchymal stromal cell (BM-MSC) treatment is a potentially effective cell therapy for cardiac disease. We investigated the effects of intravenous delivery of BM-MSCs in the acute phase post-transplant in a heterotopic heart transplantation (HHT) model associated with I/R injury. Methods: Hearts of wild-type Lewis (WT LEW) rats were harvested and transplanted heterotopically into the necks of recipient WT LEW rats. Forty-eight hours after HHT, BM-MSCs were injected intravenously into animals in the experimental group, whereas controls received normal saline (NS). Results: Eight days after BM-MSC injection, fractional shortening of transplanted hearts was significantly higher and left ventricular systolic diameter was lower in the BM-MSC group compared with controls, whereas no differences were found 28 days after infusion. A reduction in ventricular remodeling and cardiac fibrosis was observed by histochemical analysis and confirmed by cardiac magnetic resonance imaging in the BM-MSC group. The perivascular stromal cells’ density and the number of capillaries were increased whereas the number of apoptotic cells decreased significantly in transplanted hearts in the BM-MSC group compared with the NS group. Conclusions: We showed early improvement in cardiac function and subsequent enhanced ventricular remodeling, reduced cardiac fibrosis, augmented neo-vascularization and decreased cardiomyocyte apoptosis of the transplanted heart in a heterotopic transplantation model after intravenous infusion of BM-derived MSCs. Our data suggest that clinical studies with BM-MSCs are warranted to understand their effects on cardiac graft and transplant recipient survival.Fil: Montanari, Sonia. University Health Network; Canadá. University of Toronto; CanadáFil: Dayan, Victor. University Health Network; CanadáFil: Yannarelli, Gustavo Gabriel. University Health Network; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Billia, Filio. Toronto General Hospital; CanadáFil: Viswanathan, Sowmya. University Health Network; CanadáFil: Connelly, Kim A.. Keenan Research Centre; CanadáFil: Keating, Armand. University Health Network; Canadá. University of Toronto; Canad