The influence of vitamin C on systemic markers of endothelial and inflammatory cell activation in smokers and non-smokers

Abstract.

Objective and design: To determine the influence of vitamin C supplementation (500 mg, bd, 14 days) on the circulating concentrations of soluble ICAM-1 (a marker of endothelial activation), neopterin (a marker of monocyte activation), and neutrophil elastase (a marker of neutrophil activation) in smokers and non-smokers in a randomised, double-blind, placebo-controlled trial in a hospital setting.

Subjects: Twenty smokers (serum cotinine ≥ 20 ng ml⁻¹) and 20 age- and gender-matched non-smokers (serum cotinine ≤ 13.7 ng ml⁻¹).

Results: At baseline, there was a significant elevation in the concentration of sICAM-1 in smokers (median 247, IQR 199 to 357 ng ml⁻¹) compared to non-smokers (median 207, IQR 189 to 227 ng ml⁻¹; p = 0.014). Vitamin C supplementation did not influence the circulating concentrations of ICAM-1 or neopterin, or leukocyte elastase activity, in smokers, non-smokers, or in the total population.

Conclusions: Markers of monocyte and neutrophil activation were not influenced by smoking status in this study population. However, sICAM-1 concentrations were significantly elevated in tobacco smokers, reflecting tobacco-induced vascular activation that is unaffected by Vitamin C supplementation.