Cell Transplantation for the Treatment of Acute Myocardial Infarction Using Vascular Endothelial Growth Factor–Expressing Skeletal Myoblasts

Abstract

Background Vascular endothelial growth factor (VEGF) is a promising reagent for inducing myocardial angiogenesis. Skeletal myoblast transplantation has been shown to improve cardiac function in chronic heart failure models by regenerating muscle. We hypothesized that transplantation of VEGF-expressing myoblasts could effectively treat acute myocardial infarction by providing VEGF-induced cardioprotection through vasodilatation in the early phase, followed by angiogenesis effects in salvaging ischemic host myocardium combined with the functional benefits of newly formed, skeletal myoblast-derived muscle in the later phase. Methods and Results Primary rat skeletal myoblasts were transfected with the human VEGF 165 gene using hemagglutinating virus of Japan-liposome with >95% transfection efficiency. Four million of these myoblasts (VEGF group), control-transfected myoblasts (control group), or medium only (medium group) was injected into syngeneic rat hearts 1 hour after left coronary artery occlusion. Myocardial VEGF-expression increased for 2 weeks in the VEGF group, resulting in enhanced angiogenesis without the formation of tumors. Grafted myoblasts had differentiated into multinucleated myotubes within host myocardium. Infarct size (33.3±1.4%, 38.1±1.4%, and 43.7±1.6% for VEGF, control, and medium groups, respectively; P =0.0005) was significantly reduced with VEGF treatment, and cardiac function improved in the VEGF group (maximum dP/dt: 4072.0±93.6, 3772.5±101.1, and 3482.5±90.6 mm Hg/s in the 3 groups, respectively; P =0.0011; minimum dP/dt: −504.2±68.5, −2311.3±57.0, and −2124.0±57.9 mm Hg/s, respectively; P =0.0008). Conclusions This combined strategy of cell transplantation with gene therapy could be of importance for the treatment of acute myocardial infarction.