Abstract 3310: Human Peripheral Blood-derived CD31+Cells Have Robust Angio-vasculogenic Properties And Enhance Recovery Following Hindlimb Ischemia
Background: Recently, we reported that murine bone marrow derived CD31+ cells have hemangioblastic activities. In this study, we hypothesized that human peripheral blood derived CD31+ cells (hCD31+) have robust angio-vasculogenic potential and can induce therapeutic neovascularization in hindlimb ischemia.
Methods and Results: hCD31+ cells were isolated using a magnetic bead separation technique. By FACS analysis, we confirmed that more than 98% of hCD31+ cells are positive for CD45, suggesting that hCD31+ cells are not circulating endothelial cells. In endothelial progenitor cell (EPC) culture assay, hCD31+ cells almost exclusively gave rise to EPCs and produced significantly higher colony forming activity than hCD31- cells (n=5, each) (25.2 ± 2.2 vs. 3.6 ± 0.5/mm2, P<0.01). In the matrigel tube formation assay, coculturing HUVEC with hCD31+ cells revealed that hCD31+ cells robustly contributed to network formation with HUVECs suggestive of angio-vasculogenic activity. Real-time PCR showed that hCD31+ cells express higher levels of angiogenic genes (fold increase: angiopoietin-1, 5.6 ± 0.8; HGF, 2.7 ± 0.6; VEGF-A, 3.8 ± 0.5; FGF-2, 2.0 ± 0.5) and lower levels of inflammatory genes (fold decrease: Interferonγ, 13.2 ± 2.5; TNFα, 2.3 ± 0.9) than hCD31− cells. To investigate therapeutic potential, we surgically induced hindlimb ischemia in athymic nude mice, and injected hCD31+ cells, hCD31− cells and PBS into the ischemic limbs (n=9, each). The hCD31+ treated group showed a higher limb salvage rate than other groups [total salvage/tip necrosis/amputation; hCD31+ cells 5/4/0, hCD31− cells 2/5/2, PBS control 0/5/4] (P<0.01). At 14 days, perfusion ratio and capillary density were significantly higher in the hCD31+ treated group compared to the hCD31− and PBS treated groups. Histologic analysis demonstrated that a fraction of injected DiI-labeled hCD31+ cells exhibit endothelial phenotypes during the follow-up period of 8 weeks.
Conclusion: The present study demonstrated that hCD31+ cells have robust angio-vasculogenic potential with low inflammatory activity, and enhanced post-ischemia recovery. These data suggested that hCD31+ cell transplantation may represent a novel therapeutic option for treating ischemic cardiovascular diseases.