A promising strategy for the treatment of ischemic heart disease: Mesenchymal stem cell-mediated vascular endothelial growth factor gene transfer in rats.

Background: Treatment of ischemic heart disease (IHD) remains a worldwide problem. Gene therapy, and recently, cell transplantation, have made desirable progress. A combination of appropriate stem cells and angiogenic genes appears promising in treating IHD.

Objective: To study the results of angiogenesis and myogenesis induced by transplantation of the adenovirus carrying human vascular endothelial growth factor 165 (Ad-hVEGF(165))-transfected mesenchymal stem cells (MSCs) in IHD compared with direct MSC transplantation or Ad-hVEGF165 delivery.

Methods: Cultured MSCs were transfected by Ad-hVEGF(165), and secreted VEGF was measured by ELISA in vitro. Ad-hVEGF(165)-transfected MSCs (MSC/VEGF group), MSCs (MSC group), Ad-hVEGF(165) (VEGF group) or a serum-free medium (control group) was injected into syngeneic Wistar rats immediately after left coronary artery occlusion. All cells were marked with CM-DiI (Molecular Probes, USA) before transplantation. One week after treatment, messenger RNA expression of hVEGF(165) in the MSC/VEGF group was found to be significantly higher than in other groups by reverse transcriptase-polymerase chain reaction analysis. One month after cell transplantation, left ventricular (LV) ejection fraction, capillary density of the infarcted region, infarct size and hemodynamic parameters (including LV end-diastolic pressure, LV+dP/dt and LV-dP/dt) were measured and immunohistochemical analysis was performed.

Results: A high level of VEGF was expressed by Ad-hVEGF(165)-transfected MSCs. LV ejection fraction, mean capillary density of the infarcted region and hemodynamic parameters were significantly improved in the MSC/VEGF group compared with the MSC group, the VEGF group and the control group (P<0.001 for all). Partly transplanted MSCs showed the cardiomyocyte phenotype, expressed desmin and cardiac troponin T, and resulted in angiogenesis in the ischemic myocardium. However, a few transplanted MSCs incorporated into the vascular structure and most of the new vascular components were host-derived.

Conclusions: The combined strategy of MSC transplantation and VEGF gene therapy can produce effective myogenesis and host-derived angiogenesis, resulting in the prevention of progressive heart dysfunction after myocardial infarction.