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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, Damian 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 the recognition 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 alpha-lipoic acid), while the remaining 8 subjects underwent FMD assessment in response to 5 and 10 min of forearm occlusion following ingestion of AOC or placebo. Although the efficacy of the AOC was clearly documented by elevated plasma ascorbate levels (approximately 95%) and a reduced free radical concentration (approximately 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, post-occlusion shear rate (28,640 +/- 2,799 vs. 18,629 +/- 1,724/s, AUC), FMD/shear rate (approximately 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:28342
Deposited By: Mrs Julie Haydock
Deposited On:08 Jan 2014 13:18
Last Modified:08 Jan 2014 13:18

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