Short-term increases in pressure and shear stress attenuate age-related declines in endothelial function in skeletal muscle feed arteries

Eur J Appl Physiol. 2016 Jul;116(7):1305-11. doi: 10.1007/s00421-016-3388-9. Epub 2016 May 5.

Abstract

Purpose: We tested the hypothesis that exposure to a short-term (1 h) increase in intraluminal pressure and shear stress (SS), to mimic two mechanical signals associated with a bout of exercise, improves nitric oxide (NO)-mediated endothelium-dependent dilation in aged soleus muscle feed arteries (SFA). In addition, we hypothesized that pressure and SS would interact to produce greater improvements in endothelial function than pressure alone.

Methods: SFA from young (4 months) and old (24 months) Fischer 344 rats were cannulated and pressurized at 90 (P90) or 130 (P130) cmH2O and exposed to no SS (0 dyn/cm(2)) or high SS (~65 dyn/cm(2)) for 1 h. At the end of the 1 h treatment period, pressure in all P130 SFA was set to 90 cmH2O and no SS (0 dyn/cm(2)) for examination of endothelium-dependent [flow and acetylcholine (ACh)] and endothelium-independent [sodium nitroprusside (SNP)] dilation. To evaluate the contribution of NO, vasodilator responses were assessed in the presence of N(ω)-nitro- l -arginine (L-NNA).

Results: Flow- and ACh-induced dilations were impaired in Old P90 SFA. Treatment with increased pressure + SS for 1 h improved flow- and ACh-induced dilations in old SFA. The beneficial effect of pressure + SS was abolished in the presence of L-NNA and was not greater than treatment with increased pressure alone.

Conclusion: These results indicate that short-duration increases in pressure + SS improve NO-mediated endothelium-dependent dilation in aged SFA; however, pressure and SS do not interact to produce greater improvements in endothelial function than pressure alone.

Keywords: ACh-induced dilation; Aging; Endothelial dysfunction; Fischer 344 rats; Skeletal muscle feed arteries; Vascular smooth muscle.

MeSH terms

  • Aging / physiology*
  • Animals
  • Arterial Pressure / physiology*
  • Arteries / physiology*
  • Endothelium, Vascular / physiology*
  • Female
  • Male
  • Muscle, Skeletal / blood supply
  • Muscle, Skeletal / physiology*
  • Nitric Oxide / metabolism*
  • Rats
  • Rats, Inbred F344
  • Shear Strength / physiology

Substances

  • Nitric Oxide