TY - JOUR
T1 - The effect of oral antioxidants on brachial artery flow-mediated dilation following 5 and 10 min of ischemia
AU - Harris, Ryan A.
AU - Nishiyama, Steven K.
AU - Wray, D. Walter
AU - Tedjasaputra, Vince
AU - Bailey, Damian M.
AU - Richardson, Russell S.
N1 - Funding Information:
Acknowledgments The authors would like to give a special thanks to all the subjects who participated in this investigation. This study was funded in part by Tobacco-Related Disease Research Program Grant 15RT-0100, NIH PO1 HL 09183-01A1, American Heart Association grant 0835209N, and the Parker B. Francis Foundation.
PY - 2009
Y1 - 2009
N2 - 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 α-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 (∼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, post-occlusion 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.
AB - 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 α-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 (∼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, post-occlusion 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.
KW - Antioxidants
KW - Endothelial function
KW - FMD
KW - Reactive hyperemia
KW - Shear rate
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U2 - 10.1007/s00421-009-1147-x
DO - 10.1007/s00421-009-1147-x
M3 - Article
C2 - 19669786
AN - SCOPUS:70350257604
SN - 1439-6319
VL - 107
SP - 445
EP - 453
JO - European Journal of Applied Physiology
JF - European Journal of Applied Physiology
IS - 4
ER -