G-CSF-mobilized peripheral blood mononuclear cells from diabetic patients augment neovascularization in ischemic limbs but with impaired capability

Background: Autologous transplantation of mobilized peripheral blood mononuclear cells (M-PBMNCs) is a novel approach to improve critical limb ischemia (CLI) in diabetes. However, endothelial progenitor cells (EPCs) from diabetes are dysfunctional and impaired in ischemia-induced neovascularization. Objective: This study aimed to confirm the compromised efficiency of diabetic M-PBMNCs in therapeutic neovascularization, and to determine the underlying mechanisms of this impairment. Methods: Diabetic M-PBMNCs from 17 diabetic patients or healthy controls, or phosphate-buffered saline (PBS) were injected into the ischemic limbs of streptozotocin-induced diabetic nude mice. The limb blood perfusion, ambulatory score.. ischemia damage, capillary/fiber ratio, arteriole density, collateral vessel formation, and pericytes recruitment were evaluated between these three groups. Noninvasive real time image and histopathology were used to detect the in vivo role of transplanted M-PBMNCs. Proliferation and adhesion of EPCs were assayed. In vitro vascular network incorporation and matrigel plug assay were used to test the pro-neovascularization role of M-PBMNCs. Results: Transplantation of diabetic M-PBMNCs also improved neovascularization, but to a lesser extent from that observed with non-diabetic ones. This was associated with the impairment of diabetic M-PBMNCs capacity to differentiate into EPCs. to incorporate into vessel-like tubules in vitro, to participate in vascular-like structure formation in a subcutaneous matrigel plug, and to stimulate the recruitment of pericytes/smooth muscle cells. In addition, there was impairment in vasculogenesis, which was related to the reduced adhesion ability of EPCs from diabetic M-PBMNCs. Conclusions: Diabetes reduced the capacity of M-PBMNCs to augment neovascularization in ischemia.