title: Vitamin C supplementation in normal subjects reduces constitutive ICAM-1 expression.
abstract: Regulation of monocyte adhesion molecule gene expression is via redox sensitive transcription factors. We have investigated whether dietary antioxidant supplementation with vitamin C (250 mg/day) can modulate monocyte ICAM-1 expression in healthy male subjects with low plasma vitamin C at baseline. In a randomised, double-blind, crossover study, monocyte ICAM-1 mRNA was analysed using quantitative reverse transcriptase PCR. Protein was determined by flow cytometry (monocytes) and ELISA (plasma). Monocyte numbers were unaltered by supplementation. Subjects with low plasma vitamin C (<50 microM) prior to supplementation expressed higher levels of monocyte ICAM-1mRNA, and showed a significant (50%) reduction in ICAM-1mRNA expression after 6 weeks of 250 mg/day vitamin C supplementation (p<0.05). This was paralleled by a reduction in sICAM-1 (p<0.05). For the first time, these results show that dietary vitamin C can modulate monocyte ICAM-1 gene expression in vivo, where regulation of gene expression represents a novel mechanism for benefit from dietary antioxidants.
authors.affiliation: School of Life and Health Sciences, Aston University, Birmingham, UK.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Rayment
authors.forename: Jacqui
authors.initials: J
authors.lastname: Shaw
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Woollard
authors.forename: Joe
authors.initials: J
authors.lastname: Lunec
authors.forename: Helen R
authors.initials: HR
authors.lastname: Griffiths
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000097:blood; D001483:Base Sequence; D018592:Cross-Over Studies; D004311:Double-Blind Method; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D000975:Antioxidants; D012333:RNA, Messenger; D018799:Intercellular Adhesion Molecule-1; D001205:Ascorbic Acid