Abstract
Unlike quadrupeds, humans exhibit a larger hydrostatic pressure in the lower limbs compared with the upper limbs during a major part of the day. It is plausible that repeated episodes of elevated pressure in the legs may negatively impact the endothelium, hence contributing to the greater predisposition of atherosclerosis in the legs. We tested the hypothesis that an acute exposure to increased hydrostatic pressure would induce conduit artery endothelial dysfunction. In protocol 1, to mimic the hemodynamic environment of the leg, we subjected the brachial artery to a hydrostatic pressure gradient ( approximately 15 mmHg) by vertically hanging the arm for 3 h. Brachial artery flow-mediated dilation (FMD) was assessed in both arms before and following the intervention. In protocol 2, we directly evaluated popliteal artery FMD before and after a 3-h upright sitting (pressure gradient approximately 48 mmHg) and control (supine position) intervention. Our arm-hanging model effectively resembled the hemodynamic milieu (high pressure and low shear rate) present in the lower limbs during the seated position. Endothelium-dependent vasodilation at the brachial artery was attenuated following arm hanging (P < 0.05); however, contrary to our hypothesis, upright sitting did not have an impact on popliteal artery endothelial function (P > 0.05). These data suggest an intriguing vascular-specific response to increased hydrostatic pressure and reduced shear rate. Further efforts are needed to determine if this apparent protection of the leg vasculature against an acute hydrostatic challenge is attributable to posture-induced chronic adaptations.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: American Journal of Physiology-Heart and Circulatory Physiology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.