Open Collections

Shabir, Nadhiyya

University of British Columbia

Purpose: Variations in shear stimulus has been shown to impact endothelial function. Studies have shown that increases in shear improves endothelial function and overall vascular health while decreases in shear leads to impairments in endothelial function and develops risk of cardiovascular diseases. Although this pattern is noticed in adult studies, there are limited studies that investigate this relationship in children. Therefore, the aim of this study was to examine the relationship between shear rate and flow mediated dilation (FMD) in children and adults. Methods: Nine adults and seven children completed two protocols: passive heat and low-pressure cuff. Superficial femoral artery diameter, flow, shear rate, FMD were measured pre and post condition. Results: Mean shear rate increased significantly post passive heat condition in children (103.1 ± 41.5 s⁻¹ to 230.4 ± 79.1 s⁻¹) and adults (29.9 ± 12.1 s⁻¹ to 140.3 ± 36.0 s⁻¹) with a greater increase in adults than children. Despite the increases in mean shear rate and antegrade shear rate, FMD did not significantly improve post heat. There were no age-related differences in FMD responses post passive heat condition. Mean shear rate decreased significantly following low cuff condition in children (142.4 ± 67.4 s⁻¹ to 101.1 ± 22.1 s⁻¹) and adults (38.7 ± 19.5 s⁻¹ to 23.8 ± 15.4 s⁻¹). The significant increases in retrograde shear rate post low pressure cuff was followed by a significant decline in FMD in children (4.3 ± 1.8% to 2.6 ± 1.4%) and adults (4.1 ± 1.2% to 2.9 ± 0.78%). Conclusions: Passive heat can increase shear rates and flow in both children and adults but may not be enough to stimulate positive endothelial function. Low pressure cuff can impair endothelial function through decreases in shear, flow and FMD in children and adults. These findings have implications for understanding vascular function in different age groups and for developing interventions to enhance vascular health.

Text

2024-05-13

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/88283

Health and Exercise Sciences

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/