Therapeutic neovascularization by autologous transplantation with expanded endothelial progenitor cells from peripheral blood into ischemic hind limbs

Aim: To investigate the hypothesis that transplantation with expanded autologous endothelial progenitor cells (EPC) could enhance neovascularization. Methods: Peripheral blood mononuclear cells (PB-MNC) isolated from New Zealand White rabbits were cultured in vitro. At d 7, the adherent cells were collected for autologous transplantation. Rabbits with severe unilateral hind limb ischemia were randomly assigned to receive phosphate-buffered saline or expanded EPC in phosphate-buffered saline, administered by intramuscular injection in 6 sites of the ischemic thigh at postoperative d 7. Neovascularization was monitored by using the calf blood pressure ratio to indicate tissue perfusion, digital subtraction angiography to identify collateral vessel development and histological analysis of capillary density in the ischemic limb at d 35 after surgery. Results: Autologous EPC transplantation produced significant amelioration in ischemic hind limbs, as indicated by a greater calf blood pressure ratio (0.52±0.04 vs 0.42±0.05, P<0.01), angiographic score (1.44±0.06 vs 0.98±0.08, P<0.01) and capillary density in muscle (195.2±5.4/mm² vs 169.4±6.4/mm², P<0.05), than controls. Conclusion: Transplantation of autologous expanded EPC can promote neovascularization in ischemic hindlimbs.