In mice with type 2 diabetes, a vascular endothelial growth factor (VEGF)-activating transcription factor modulates VEGF signaling and induces therapeutic angiogenesis after hindlimb ischemia

Abstract

Peripheral arterial disease is a major complication of diabetes. The ability to promote therapeutic angiogenesis may be limited in diabetes. Type 2 diabetes was induced by high-fat feeding C57BL/6 mice (n = 60). Normal chow-fed mice (n = 20) had no diabetes. Mice underwent unilateral femoral artery ligation and excision. A plasmid DNA encoded an engineered transcription factor designed to increase vascular endothelial growth factor expression (ZFP-VEGF). On day 10 after the operation, the ischemic limbs received 125 microg ZFP-VEGF plasmid or control. Mice were killed 3, 10, or 20 days after injection (n = 10/group, at each time point). Limb blood flow was measured by laser Doppler perfusion imaging. VEGF mRNA expression was examined by real-time PCR. VEGF, Akt, and phospho-Akt protein were measured by enzyme-linked immunosorbent assay. Capillary density, proliferation, and apoptosis were assessed histologically. Compared with normal mice, mice with diabetes had greater VEGF protein, reduced phospho-Akt-to-Akt ratio before ligation, and an impaired perfusion recovery after ligation. At 3 and 10 days after injection, in mice with diabetes, gene transfer increased VEGF expression and signaling. At later time points, gene transfer resulted in better perfusion recovery. Gene transfer with ZFP-VEGF was able to promote therapeutic angiogenesis mice with type 2 diabetes.