title: The influence of vitamin C on systemic markers of endothelial and inflammatory cell activation in smokers and non-smokers.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  Twenty smokers (serum cotinine > or = 20 ng ml(-1)) and 20 age- and gender-matched non-smokers (serum cotinine < or = 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.
authors.affiliation: Periodontics, Endodontics and Dental Hygiene, School of Dentistry, University of Louisville, 501 South Preston, Louisville, KY 40202, USA. dascot07@louisville.edu
authors.forename: D A
authors.initials: DA
authors.lastname: Scott
authors.forename: R N
authors.initials: RN
authors.lastname: Poston
authors.forename: R F
authors.initials: RF
authors.lastname: Wilson
authors.forename: P Y
authors.initials: PY
authors.lastname: Coward
authors.forename: R M
authors.initials: RM
authors.lastname: Palmer
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology*; D015415:Biomarkers; D003367:Cotinine / Q000097:blood; D004727:Endothelium / Q000473:pathology*; D005260:Female; D006801:Humans; D007249:Inflammation; D018799:Intercellular Adhesion Molecule-1 / Q000097:blood*; D019272:Leukocyte Elastase / Q000096:biosynthesis; D008168:Lung / Q000187:drug effects* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D019798:Neopterin / Q000097:blood*; D010919:Placebos; D012907:Smoking; D013997:Time Factors
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D010919:Placebos; D018799:Intercellular Adhesion Molecule-1; D019798:Neopterin; D019272:Leukocyte Elastase; D003367:Cotinine; D001205:Ascorbic Acid