title: The LPS-induced increase in circulating microparticles is not affected by vitamin C in humans.
abstract: OBJECTIVE
  Microparticles (MP) are considered to promote coagulation. This study aimed to characterize the time course of MP levels and the effect of high-dose vitamin C on MP formation during inflammation in an in vivo Escherichia coli endotoxin (LPS) model.
  
  
  METHODS
  Microparticle formation was studied in 14 male subjects in a cross-over trial who received either intravenous vitamin C at 320 mg/kg body weight (BW) or 480 mg/kg BW or saline solution in a random order on alternate trial days 3 h after intravenous exposure to LPS (2 ng/kg BW). Venous blood samples were taken before, 3 and 6 h after LPS. D-dimer, leucocyte count, C-reactive protein, plasma vitamin C and body temperature were assessed as inflammatory parameters. MP were detected using flow cytometric analysis and expressed in 10³ MP/mL plasma.
  
  
  RESULTS
  Microparticles levels were decreased from baseline 848 units [range 431-1705] by 21% to 671 units [253-1586] at 3 h and increased by 32% to 1119 units [288-4443] at 6 h after LPS. This pattern was not influenced by administration of vitamin C, with a change from 730 units [399-1396] at baseline by an increase to 832 units [215-2168] at 3 h to 1055 units [350-4858] at 6 h. MP subpopulations followed similar dynamics. Alterations in inflammatory parameters were independent from vitamin C administration during endotoxemia.
  
  
  CONCLUSIONS
  Microparticles are increased in acute systemic inflammation with inconsistent changes in MP subgroups in healthy subjects. Systemic vitamin C administration does not mitigate MP formation and D-dimer levels during acute systemic inflammation, suggesting that MP-induced coagulation activity is not affected by vitamin C.
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Weisshaar
authors.forename: Ghazaleh
authors.initials: G
authors.lastname: Gouya
authors.forename: Daniel
authors.initials: D
authors.lastname: Nguyen
authors.forename: Stylianos
authors.initials: S
authors.lastname: Kapiotis
authors.forename: Michael
authors.initials: M
authors.lastname: Wolzt
mesh_terms: D061605:Administration, Intravenous; D000328:Adult; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000097:blood; D001831:Body Temperature; D002097:C-Reactive Protein / Q000378:metabolism; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D018592:Cross-Over Studies; D004731:Endotoxins / Q000008:administration & dosage*; D005434:Flow Cytometry; D006801:Humans; D007958:Leukocyte Count; D008070:Lipopolysaccharides / Q000008:administration & dosage*; D008297:Male; D014815:Vitamins / Q000008:administration & dosage* / Q000097:blood
chemical_list: D004731:Endotoxins; D008070:Lipopolysaccharides; D014815:Vitamins; C044101:endotoxin, Escherichia coli; D002097:C-Reactive Protein; D001205:Ascorbic Acid