COMP-angiopoietin-1 enhances skeletal muscle blood flow and insulin sensitivity in mice

To test whether chronic enhanced blood flow alters insulin-stimulated glucose uptake, we measured skeletal muscle glucose uptake in chow-fed and high-fat-fed mice injected with adenovirus containing modified angiopoietin-1, COMP-Ang1, via euglycemic-hyperinsulinemic clamp. Blood flow rates and platelet endothelial cell adhesion molecule-1 positive endothelial cells in the hindlimb skeletal muscle were elevated in COMP-Ang1 compared with control LacZ. Whole body glucose uptake and whole body glycogen/lipid synthesis were elevated in COMP-Ang1 compared with LacZ in chow diet. High-fat diet significantly reduced whole body glucose uptake and whole body glycolysis in LacZ mice, whereas high-fat-fed COMP-Ang1 showed a level of whole body glucose uptake that was comparable with chow-fed LacZ and showed increased glucose uptake compared with high-fat-fed LacZ. Glucose uptake and glycolysis in gastrocnemius muscle of chow-fed COMP-Ang1 were increased compared with chow-fed LacZ. High-fat diet-induced whole body insulin resistance in the LacZ was mostly due to approximately 40% decrease in insulin-stimulated glucose uptake in skeletal muscle. In contrast, COMP-Ang1 prevented diet-induced skeletal muscle insulin resistance compared with high-fat-fed LacZ. Akt phosphorylation in skeletal muscle was increased in COMP-Ang1 compared with LacZ in both chow-fed and high-fat-fed groups. These results suggest that increased blood flow by COMP-Ang1 increases insulin-stimulated glucose uptake and prevents high-fat diet-induced insulin resistance in skeletal muscle.