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

Ryan A. Harris, Steven K Nishiyama, D. Walter Wray, Vince Tedjasaputra, Damian M Bailey, Russell S Richardson

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    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
    Original languageEnglish
    Pages (from-to)445-453
    JournalEuropean Journal of Applied Physiology
    Volume107
    DOIs
    Publication statusPublished - 11 Aug 2009

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    Keywords

    • Shear rate
    • Reactive hyperemia
    • Endothelial function
    • FMD
    • Antioxidants

    Cite this

    Harris, R. A., Nishiyama, S. K., Wray, D. W., Tedjasaputra, V., Bailey, D. M., & Richardson, R. 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, 445-453. https://doi.org/10.1007/s00421-009-1147-x