| Summary |
In the current study, we examined if similar differences in skeletal muscle capillarization and VEGF expression exist in aged compared to young men. Muscle biopsies of the vastus lateralis muscle were obtained from seven aged (65 ± 2 yrs) and eight young (21 ± 1 yrs) men before and four hours after a sub-maximal exercise bout. Muscle samples were measured for capillarization, VEGF mRNA, and VEGF protein. Capillary contacts (CC) were significantly lower in aged men for all skeletal muscle fiber types. Aged men also demonstrated significantly lower C/Fi in type I fibers, and lower capillary-to-fiber perimeter exchange index (CFPE) in type I fibers. In addition, aged men had significantly lower VEGF protein and the exercise induced increase in VEGF mRNA was significantly lower in aged men. Regression analysis revealed several significant relationships: greater type I CC was associated with greater VEGF protein, greater CFPE was associated with greater maximal oxygen consumption (Vc>2max), and greater CFPE was associated with greater insulin sensitivity. Thus, The principle findings of this study are as follows: 1) resting VEGF mRNA and protein are lower in aged men compared to young; 2) overall CC, C/Fi, and CFPE were lower in aged men; 3) there is a significant relationship between CC and VEGF protein and between CC and FCSA 4) there are significant relationships between CFPE and VcUmax and CFPE and insulin sensitivity. |
