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The effect of oral antioxidants on brachial artery flow-mediated dilation following 5 and 10 min of ischemia

Harris, Ryan A., Nishiyama, Steven K., Wray, D.Walter, Tedjasaputra, Vince, Bailey, Damien M. and Richardson, Russell S. (2009) The effect of oral antioxidants on brachial artery flow-mediated dilation following 5 and 10 min of ischemia. European Journal of Applied Physiology, 107 . pp. 445-453. [Journal article]

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DOI: 10.1007/s00421-009-1147-x

Abstract

In light of the current methodological developments in flow-mediated dilation (FMD) testing and therecognition that oxidative stress may play an important role in regulating this process, the present study sought to: (1) compare flow-mediated dilation (FMD) following 5 and 10 min of forearm cuff occlusion, and (2) evaluate the role of oxidative stress on vasodilation, both distal and proximal to the cuff. Of the 14 subjects studied, 6 partook solely in a validation study of the antioxidant cocktail (AOC; vitamins C, E, and a-lipoic acid), while the remaining 8 subjects underwent FMD assessment in response to 5 and 10 min of forearm occlusion following ingestion ofAOC or placebo.Although the efficacy of the AOC was clearly documented by elevated plasma ascorbate levels (*95%) and a reduced free radical concentration (*65%), no effects of acute oral antioxidants were observed. FMD was significantly augmented in response to 10 min of forearm occlusion when compared to 5 min, whether expressed as % change (10.1 ± 2 vs. 4.5 ± 1%, respectively) or absolute change in diameter (0.035 ± 0.005 vs. 0.018 ± 0.005 cm, respectively). Additionally, postocclusion shear rate (28,640 ± 2,799 vs. 18,629 ± 1,724/s, AUC), FMD/shear rate (*50%), and time to peak dilation (68 ± 7 vs. 53 ± 8 s) were greater following 10 min of occlusion. In contrast to previous studies, this investigation has identified a greater brachial artery FMD in response to 10 versus 5 min of forearm ischemia, which appears to be unexplained by oxidative stress.

Item Type:Journal article
Keywords:Shear rate Reactive hyperemia Endothelial function FMD Antioxidants
Faculties and Schools:Faculty of Life and Health Sciences > School of Sport
Faculty of Life and Health Sciences
Research Institutes and Groups:Sport and Exercise Sciences Research Institute
ID Code:28314
Deposited By: Mrs Julie Haydock
Deposited On:06 Jan 2014 10:57
Last Modified:06 Jan 2014 10:57

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