Objective There are two types of endothelial progenitor cell (EPC) in bone marrow (BM) and circulation, BM-EPC and Circulation late endothelial progenitor cell (CL-EPC). Diabetes impairs the function of EPC, but it is not clear whether transplantation of EPC can rescue ischemic myocardium in diabetes. In this study, we compared the function of BM-EPC and CL-EPC in vitro. Then we administered BM-EPC and CL-EPC intramyocardially and compared their contribution to vasculogenesis in diabetic rabbits.

Methods BM-EPC and CL-EPC from healthy and diabetic rabbits were isolated and subjected to in vitro proliferation, tube-forming, angiogenic cytokine assays. Exogenous BM-EPC and CL-EPC were analysed for therapeutic efficacy in an acute ischemia model of diabetic rabbits. LVfunction was assessed using echocardiography. The capillary density and fibrosis area were evaluated. mRNA expression of VEGF and bFGF was analysed using relative realtime quantitive PCR.

Results Proliferation, tube-forming, secretion of VEGF and bFGF of diabetic EPC were significantly reduced compared with healthy EPC. In diabetic rabbits, healthy BM-EPC transplantation could increase capillary density and improve cardiac function, decrease fibrosis area compared with CL-EPC and the control group. Real time PCR indicated that mRNA expression of VEGF and bFGF were augmented more in the healthy BM-EPC group than those in the control and CL-EPC groups.

Conclusions These findings suggest that diabetes impairs the function of EPC. Transplantation of healthy BM-EPC may rescue the ischemic myocardium by neovasculogenesis and paracrine effect in diabetic rabbits. However, autologous transplantation of CL-EPC could not enhance cardiac function.