Effects of exercise training with weight loss on skeletal muscle expression of angiogenic factors in overweight and obese older men

Abstract

Low skeletal muscle capillarization is associated with impaired glucose tolerance (IGT); however, aerobic exercise training with weight loss (AEX+WL) increases skeletal muscle capillarization and improves glucose tolerance in adults with IGT. Given that expression of angiogenic growth factors mediates skeletal muscle capillarization, we sought to determine whether angiogenic growth factor levels are associated with low capillarization in those with IGT vs. normal glucose tolerance (NGT), or to the benefits of AEX+WL in both groups. Sixteen overweight or obese men 50-75 years of age completed 6 months of AEX+WL with oral glucose tolerance tests and vastus lateralis muscle biopsies for measurement of muscle vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble fms-like tyrosine kinase receptor-1 (sFlt-1) and basic fibroblast growth factor (bFGF). At baseline, all growth factor levels were numerically lower in IGT compared with NGT, but these did not reach statistical significance (P=0.06-0.33). Following AEX+WL, aerobic capacity (VO2max) increased by 16%, while body weight and 120-minute postprandial glucose levels decreased by 10% and 15%, respectively (P ≤ 0.001 for all). There was a main effect of AEX+WL to increase VEGF (0.095±0.016 vs. 0.114±0.018 ng/µg, P<0.05), PlGF (0.004±0.001 vs. 0.005±0.001 ng/µg, P<0.05), and sFlt-1 (0.216±0.029 vs. 0.264±0.036 ng/µg, P<0.01) with overall increases driven by the IGT group. These results suggest that 6 months of AEX+WL increases skeletal muscle angiogenic growth factor levels in older, obese adults with IGT and NGT, which may contribute to our previous findings that AEX+WL increases capillarization to improve glucose tolerance in those with IGT.