Progenitor cell transplantation has been considered as a potential angiogenesis therapy for the ischemic hindlimb. In this work we performed an ischemic hindlimb model in dogs. We ligated the middle sacra and the external right iliac arteries. After 7 days, the femoral artery was ligated and removed, and three Silastic tubes were inserted into the gracilis muscle to create fibrocollagenous tunnels. After Silastic implantation, we administered saline or granulocyte colony stimulating factor (G-CSF) subcutaneously daily during 5 days. Fourteen days after device positioning we transplanted bone marrow mononuclear cells (BMMC) into the tunnels previously formed by Silastic tube reaction. Twenty-eight days later, contrasted angiographies were performed and angiographic scores were calculated. Also, vessels and endothelial cells and proliferating cells were identified by immunochemistry of muscle sections. Results demonstrated that BMMC transplantation enriched by G-CSF administration significantly stimulates angiogenesis in the ischemic hindlimb, and more than BMMC transplantation alone. Transplantation of progenitor cells in an appropriate extracellular matrix is a potential therapy for hindlimb ischemia.

Peripheral blood mononuclear cells (PBMCs) contain a cell fraction of mononuclear progenitor cells (MPCs), which own significant angiogenic potential. Autologous transplant of PBMC and/or platelet-rich plasma (PRP) promotes endothelial cells differentiation in experimental lower limb ischemia, which is considered a safe and effective strategy to support revascularization, either in animal models or clinical trials. In addition, thrombin has been proposed to enrich biological scaffolds, hence increasing MPC viability after intramuscular administration, whereas proangiogenic mediators such as vascular endothelial growth factor (VEGF), tumor necrosis factor alpha (TNF-α), inhibitor of the plasminogen activator-1 (PAI-1), and chemokine (CXCL1; GRO-α) participate in the endothelial response to ischemia, through their proangiogenic effects over endothelial cells proliferation, survival, migration, endothelial integrity maintenance, and physiologic vascular response to injury. In the present study, we describe the effect of autologous PBMCs transplant and PRP, either with or without thrombin, over proangiogenic mediators (measured by enzyme-linked immunosorbent assay) and revascularization response (angiographic vascular pattern at 30 days after vascular occlusion) in a rat model of lower limb ischemia. The group treated with PBMC + PRP significantly induced PAI-1, an effect that was prevented by the addition of thrombin. Furthermore, treatment with PBMC + PRP + thrombin resulted in the induction of VEGF. GRO-α showed a sensitive induction of all proangiogenic mediators. All treatments significantly stimulated revascularization, according to angiographic assessment, whereas higher effect was observed with PBMC + PRP treatment (p < .0001). In conclusion, autologous PBMC transplant stimulates revascularization during experimental ischemia of the lower limb, whereas

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Critical limb ischemia is a medical condition that decreases blood flow and limb oxygen supply; this disease in its late stages of progression leads to only two possible options: either surgical bypass revascularization or limb amputation. We investigated a novel method using autologous transplantation of progenitor cells derived from mobilized peripheral blood bone marrow mononuclear cells to evaluate its longterm effect as a cell therapy to induce neo-angiogenesis and restore blood flow in the affected ischemic limbs. A total of 20 ischemic limbs from critical limb ischemia diagnosed patients, non candidates to surgical revascularization were transplanted with autologous progenitor cells by either intramuscular combined with intravenous (group A) or intramuscular (group B) procedure. Patients were monitored during 31 months. Treatment efficacy was evaluated according to the following parameters: ankle brachial index which increased at a range of 0.29 -1.0 in group A and 0.40 -0.90 in group B; pain-free walking distance which increased at a range of 50 -600 m in group A and 50 -300 m in group B; and blood perfusion (measured by Laser Doppler) which increased at a range of 48 -299 in group A and 135 -225 in group B. We achieved 90% treated ischemic limbs free of amputation in both transplanted groups. Results here described provide a safe, efficient and minimally invasive therapy with progenitor cells to induce angiogenesis and preserve limbs from amputation in CLI diagnosed patients.