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Effect of oxidative stress on racial differences in vascular function at rest and during hand grip exercise
Rebecca M Kappus1, Kanokwan Bunsawat, Michael D Brown
1aDepartment of Health and Exercise Science, Appalachian State University, Boone, North Carolina bDepartment of Kinesiology and Nutrition cDepartment of Physical Therapy, University of Illinois at Chicago, Chicago, Illinois, USA.
Insights
Antioxidant supplementation affects blood vessel function differently in older adults based on race. This study explored how age and race impact vascular responses to antioxidants.
Area of Science:
- Cardiovascular research
- Aging and health
- Racial health disparities
Background:
- Hypertension prevalence is higher in African-Americans than whites, potentially linked to oxidative stress and vascular dysfunction.
- The influence of aging on oxidative stress and vascular function across racial groups remains unclear.
Purpose of the Study:
- To investigate the differential effects of antioxidant supplementation on vascular function in young and older African-American and white adults.
- To determine the impact of age and race on oxidative stress and vascular responses to antioxidants.
Main Methods:
- A double-blind, randomized, cross-over study involving 93 participants (young/older, African-American/white).
- Participants received antioxidant (AOX) or placebo supplementation.
- Evaluated endothelial function, exercise blood flow, and oxidative stress biomarkers.
Main Results:
- Young adults showed racial differences in resistance vessel response but not macrovascular function post-AOX.
- Older white adults improved resistance vessel function with AOX, while older African-Americans showed reduced function.
- Macrovascular function improved in both older races with AOX, more so in African-Americans.
Conclusions:
- Antioxidant supplementation has differential effects on macrovascular and resistance vessel function.
- These effects are significantly influenced by both participant age and race.
Objectives:
African-Americans have a higher prevalence of hypertension compared with whites, possibly due to elevated oxidative stress and subsequent vascular dysfunction. It is unclear the contribution of aging on oxidative stress and vascular function in a racially diverse cohort.
Methods:
Ninety-three young and older African-American and white participants received antioxidant (AOX) or placebo supplementation in a double-blind, randomized, cross-over design. Measures of endothelial function (reactive hyperemia, flow-mediated dilation), exercise blood flow, and biomarkers of oxidative stress and AOX activity were measured following supplementation.
Results:
In young adults, there were racial differences in resistance vessel response to reactive hyperemia and no effects of race on macrovascular function following AOX supplementation. Following AOX supplementation, older white adults improved while African-Americans reduced resistance vessel function responses to reactive hyperemia, whereas macrovascular function improved in both races, with a greater increase in African-Americans. There were racial differences in blood flow normalized to lean mass during handgrip exercise at 20% maximal voluntary contraction in the young group and AOX supplementation led to increased forearm vascular conductance in older whites with a decrease in older African-Americans. There was a supplement effect in superoxide dismutase activity in younger adults only.
Conclusion:
The results of the current study show that there are differential effects of AOX supplementation on macrovascular and resistance vessel function, and this is impacted by both age and race.
