The Impact of Age on the Vasodilatory Capacity of Human Skeletal Muscle Feed Arteries

The effect of aging on the vasodilatory capacity of human skeletal muscle feed arteries (FAs), recognized to be important regulators of muscle blood flow, has not been elucidated. Purpose To determine the impact of age on FA vasodilatory capacity. We hypothesized that vasodilation will be attenuated in FAs from old compared to young individuals and that this difference will be endothelium dependent. Methods FAs (754.5±53.3 μm) were obtained from young (33±2 yr; n=10) and old (62±2 yr; n=7) human subjects and studied using pressure myography. Vasodilation (%) was assessed in response to three stimuli 1) flow induced shear stress (Δ29 mmHg), 2) acetylcholine (ACh, 10 −3 M), and 3) sodium nitropusside (SNP, 10 −4 M), with the latter two discerning endothelium dependent and independent vasodilation. Results Both flow (old: 32±7 vs young: 68±11 %) and ACh (old: 73±4 vs young: 92±3 %) ‐induced vasodilation of the FAs were significantly blunted ( p < 0.05) in the old compared to the young. In contrast, there was no impact of age on the vasodilation induced by SNP (old: 102±4 vs young: 112±11 %). Conclusion This study has documented that the endothelium‐mediated vasodilatory capacity of FAs, but not smooth muscle function, is impacted by age. Given the potential role of FAs in the regulation of blood flow, these findings may help to explain the attenuated perfusion of skeletal muscle associated with aging.