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Fluctuation in Shear Rate, with Unaltered Mean Shear Rate, Improves Brachial Artery Flow-mediated Dilation in Healthy Young Men.

Holder, Sophie, M., Dawson, Ellen, A., Brislane, Aine ORCID: https://orcid.org/0000-0002-3214-6544, Hisdal, Jonny, Green, Daniel, J. and Thijssen, Dick, H.J. (2019) Fluctuation in Shear Rate, with Unaltered Mean Shear Rate, Improves Brachial Artery Flow-mediated Dilation in Healthy Young Men. Journal of Applied Physiology.

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Abstract

Aim: Increase in mean shear stress represents an important and potent hemodynamic stimulus to improve conduit artery endothelial function in humans. No previous study has examined whether fluctuations in shear rate patterns, without altering mean shear stress, impacts conduit artery endothelial function. This study
examined the hypothesis that 30-minutes exposure to fluctuations in shear rate patterns, in the presence of unaltered mean shear rate, improves brachial artery
flow-mediated dilation.
Methods: Fifteen healthy males (27.3±5.0 years) completed the study. Bilateral brachial artery flow-mediated dilation was assessed before and after unilateral
exposure to 30-minutes of intermittent negative pressure (10seconds -40mmHg, 7seconds 0mmHg) to induce fluctuation in shear rate, whilst the contra-lateral arm was exposed to a resting period.
Results: Negative pressure significantly increased shear rate, followed by a decrease in shear rate upon pressure release (both P<0.001). Across the 30-minute intervention, mean shear rate was not different compared to baseline (P=0.458). A linear mixed model revealed a significant effect of time was observed for flow51
mediated dilation (P=0.029), with exploratory post-hoc analysis showing an increase in the intervention arm (ΔFMD +2.0%, P=0.008), but not in the contra-lateral control arm (ΔFMD +0.5%, P=0.664). However, there was no effect for arm (P=0.619) or interaction effect (P=0.096).
Conclusion: In conclusion, we found that fluctuations in shear patterns, with unaltered mean shear, improves brachial artery flow-mediated dilation. These novel data suggest that fluctuations in shear pattern, even in the absence of altered mean shear, represents a stimulus to acute change in endothelial function in healthy individuals.

Item Type: Article
Status: Published
DOI: https://doi.org/10.1152/japplphysiol.00009.2019
Subjects: Q Science > Q Science (General)
Q Science > QP Physiology
School/Department: School of Sport
URI: http://ray.yorksj.ac.uk/id/eprint/3866

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