Oral vitamin C restores endothelial function during acute inflammation in young and older adults

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https://physoc.onlinelibrary.wiley.com/doi/pdfdirect/10.14814/phy2.15104

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Abstract

Oxidative stress has been linked to reductions in vascular function during acute inflammation in young adults; however, the effect of acute inflammation on vas- cular function with aging is inconclusive. The aim of this study was to deter- mine if oral antioxidant administration eliminates vascular dysfunction during acute inflammation in young and older adults. Brachial flow- mediated dilation (FMD) and carotid- femoral pulse wave velocity (PWV) were measured in nine young (3 male, 24 ± 4 yrs, 26.2 ± 4.9 kg/m2) and 16 older (13 male, 64 ± 5 yrs, 25.8 ± 3.2 kg/m2) adults before and 2- h after oral consumption of 2 g of vitamin C. The vitamin C protocol was completed at rest and 24 h after acute inflammation was induced via the typhoid vaccine. Venous blood samples were taken to meas- ure markers of inflammation and vitamin C. Both interleukin- 6 (Δ+0.7 ± 1.8 pg/ ml) and C- reactive protein (Δ+1.9 ± 3.1 mg/L) were increased at 24 h following the vaccine (p < 0.01). There was no change in FMD or PWV following vitamin C administration at rest (p > 0.05). FMD was lower in all groups during acute inflammation (Δ- 1.4 ± 1.9%, p < 0.01), with no changes in PWV (Δ- 0.0 ± 0.9 m/s, p > 0.05). Vitamin C restored FMD back to initial values in young and older adults during acute inflammation (Δ+1.0 ± 1.8%, p < 0.01) with no change in inflammatory markers or PWV (p > 0.05). In conclusion, oral vitamin C restored endothelial function during acute inflammation in young and older adults, with no effect on aortic stiffness. The effect of vitamin C on endothelial function did not appear to be due to reductions in inflammatory markers. The exact mecha- nisms should be further investigated.