SDF-1 Combined With Peripheral Blood Endothelial Progenitor Cells Transplantation For The Treatment Of Hindlimb Ischemia In Nude Mice

Objective Endothelial progenitor cells (EPCs) as a class of precursor cells, which can cycle, proliferate and differentiate into mature endothelial cells, not only involved in embryonic vascular development, but also played an important role in the adult organism angiogenesis in adult bone marrow and peripheral blood. Studies have shown that EPCs plays an important role in the incidence and development of lower extremity ischemic disease in recent years, the reduce of endothelial progenitor cells indicates that the endothelial repair capacity reduced and incidence of vascular disease increased. EPCs contribute to the formation of the new blood vessels in the ischemic part, the therapeutic neovascularizationt of limb ischemia became a research focus, and initial results has achieved.The bone marrow stromal cell-derived factor -1 (SDF-1) is a cytokine which been able to make EPCs homing to the area of vascular injury or tissue ischemia. SDF-1αis a subtype in SDF-1 family continuous expression in the bone marrow stromal cells, endothelial cells and hematopoietic progenitor cells.In this experiment, hindlimb ischemia model was established in nude mice. To explore the ability of SDF-1 and its antagonist AMD3100 in homing of EPCs and angiogenesis ability. Offer the experimental basis of stem cells and SDF-1 in the treatment of limb ischemia, and a new way in enhancing the effectiveness of clinical stem cell transplantation. Methods The mononuclear cells (MNCs) were harvested from the human peripheral blood, isolated by the density gradient centrifugation and cultured in the fibronectin-coated culture plates.EPCs were identified by immunofluorescence. Hindlimb ischemia model was established by ligation of femoral artery in nude mice, which was divided into five groups randomizedly: Ischemic control group(A), Peripheral blood EPCs transplantation group(B), SDF-1 local application group(C), SDF-1 combined EPCs group(D), SDF-1 combined AMD3100 treated EPCs group(E). Local CD34+VEGFR+ cells in the hind gastrocnemius were detected at day 3,7 after transplantation. The intensity of neovasculorization were evaluated at day 28.Results EPCs became spindle-shaped or round after 7 days, has radial colony formation and showed positive yellow fluorescence by DiI-acLDL and FITC-UEA-1 double staining. The double-positive cells number in control group, EPCs group, SDF-1 group, SDF-1 + EPCs group, SDF-1 + AMD3100 EPCs group were 0.00±0.00,5.30±0.65,0.00±0.00,10.31±0.63,1.86±0.17 and 0.00±0.00,7.05±0.18,0.00±0.00,11.81±0.53,2.83±0.48 at 3 and 7d respectively, the number of new capillaries in each group above were 3.00±0.13,6.15±0.04,6.20±0.10,10.65±0.08,6.21±0.08 at 28 d.Conclusions Human peripheral blood mononuclear cells could be induced to differentiate into EPCs. SDF-1 can increase the CD34+VEGFR+ cells (P <0.05) and the number of new vessels (P <0.05) in ischemic limb. SDF-1 combined EPCs can further improve the number of new vessels (P <0.05). SDF-1 can enhance the ability of blood vessel formation and promote angiogenesis by promoting EPCs homing to the ischemic. Its'effect could be blocked by AMD3100.