Abstract 225: Role Of PEDF In Regulation Of Skeletal Blood Flow And Neovascularization In Ischemic Limb Via Interaction With VEGF
[Introduction] We reported that pigment epithelium-derived factor (PEDF) plays an important role in the angiogenesis, vascular permeability and regulation of blood flow in the eye and brain via interaction with VEGF.
[Objective] We examined the role of PEDF in ischemia or VEGF-related angiogenesis or regulation of blood flow in severe limb ischemia.
[Methods] Unilateral hindlimb ischemia was performed in klotho-mice by binding the unilateral femoral artery. After hindlimb ischemia was surgically induced, we injected saline (control group) or VEGF (3 μg/day × 7, VEGF group) to ischemic limb from day 1 to 7. The expression level of PEDF in the ischemic tissue was examined by RT-PCR method. Furthermore, we injected recombinant mouse PEDF (4 μg/day × 7) or anti-PEDF antibody (60 μg/day × 7) in addition to VEGF (VEGF + PEDF group and VEGF + anti-PEDF group, respectively) to ischemic limb from day 1 to 7. We evaluated limb blood flow by laser doppler blood-flow (LDBF) at day 0, 3, 7, and 14, and number of CD34 positive cells in the ischemic tissue by histology as an index of ischemic angiogenesis at day 7 in all groups.
[Results] Expression levels of PEDF in ischemic tissue were significantly elevated in VEGF group. In VEGF group, the ischemic/normal limb blood flow ratio by LDBF analysis and number of CD34 positive cells were significantly increased compared with control group (p < 0.05). The effects of VEGF on blood flow or number of CD34 positive cells were completely abolished by administration of PEDF. Furthermore, anti-PEDF group, accelerated recover of blood flow in ischemic limb, but not number of CD34 positive cells compared in VEGF administration.
[Conclusion] VEGF augmented the expression level of PEDF in the ischemic limb. VEGF-induced ischemic angiogenesis was abolished by exogenous administration of PEDF. Furthermore, anti-PEDF antibody augmented VEGF-induced increase of blood flow. These results suggest that PEDF may play an important role in regulation of skeletal blood flow and neovascularization in ischemic limb via interaction with VEGF.