Exercise‐Like Mechanical Stimulation of Soleus Feed Arteries (SFA) Attenuates Age‐Induced Endothelial Dysfunction

Abstract

ObjectiveTo determine the mechanism of exercise‐induced attenuation of the detrimental effects of aging on endothelial function. We tested the hypothesis that exercise‐like mechanical stimulation of aged SFA with an acute increase in intraluminal pressure in combination with an increase in intraluminal shear stress would induce greater improvements in endothelium‐dependent dilation than an acute increase in intraluminal pressure alone. Methods: SFA from young and old, Fischer 344 rats were pressurized at 90 cmH20 or 130 cmH20 (P130). P130 arteries were exposed to no shear stress (0 dyn/cm2) or high shear stress (~65 dyn/cm2) for 1 h. Following the 1 h treatment period, pressure in the P130 arteries was reduced to 90 cmH2O for examination of endothelium‐dependent [acetylcholine (ACh)] and endothelium‐independent [sodium nitroprusside (SNP)] dilation.ResultsACh‐induced vasodilation was impaired in old SFA compared to young SFA. Mechanical stimulation with increased pressure for 1 h improved ACh‐induced dilation in old SFA. Stimulation of old SFA with an increase in pressure plus shear stress also improved ACh‐induced. There were no between‐group differences in SNP‐induced dilation.ConclusionThese results indicate that stimulation with an acute increase in intraluminal pressure alone or in combination with an acute increase in shear stress improves endothelium‐dependent dilation. Research support: AHA grant 0765043Y, AHA grant 4150031, The National Space Biomedical Research Institute through NCC 9‐58 and a Sydney and JL Huffines Institute of Sports Medicine Graduate Student Research Grant.