title: Decreased procoagulant phospholipids in patients treated by vitamin K antagonists.
abstract: BACKGROUND
  The stimulation of cells by thrombin is associated with the release of microparticles (MPs) from cell membranes. These MPs can express procoagulant activity. As vitamin K antagonists (VKA) decrease the generation of thrombin, we compared plasma procoagulant phospholipids (PPL) levels in patients with a previous history of venous thrombosis who were being treated with VKA and compared them with an untreated group.
  
  
  METHODS
  Plasma PPL were measured using a factor Xa-based coagulation assay. sGPV, a marker of platelet activation by thrombin, was measured by ELISA. Platelet MPs were also evaluated using standard flow cytometric techniques. Ninety-six VKA-treated patients and 80 patients not undergoing VKA therapy were tested and the results compared.
  
  
  RESULTS
  PPL activity was significantly reduced (p<0.0001) in VKA-treated patients compared with the untreated group. PPL were correlated with platelet and white blood cell count and with sGPV levels in the untreated group, but not in VKA-treated patients. PPL were correlated with fibrinogen levels in both groups, but not with C-reactive protein. Polymorphonuclear neutrophils (PMN) were significantly lower (p=0.01) in VKA-treated patients than in untreated patients.
  
  
  CONCLUSIONS
  The difference between PPL levels in VKA-treated patients and patients without treatment could be related to the decrease in PMN count. It remains to be established if this decrease of PPL is directly related to the capacity of activated PMN to generate MPs, or indirectly by reducing the amount of pro-inflammatory cytokines or reactive oxygen species produced by PMN.
authors.affiliation: Diagnostica Stago, 125 avenue Louis Roche, 92635 Gennevilliers cedex, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Rousseau
authors.forename: Barry
authors.initials: B
authors.lastname: Woodhams
authors.forename: Michèle
authors.initials: M
authors.lastname: Paunet-Bobo
authors.forename: Patrick
authors.initials: P
authors.lastname: Van Dreden
authors.forename: Dany
authors.initials: D
authors.lastname: Bigot
authors.forename: Sylviane
authors.initials: S
authors.lastname: Leclerc
authors.forename: Bernard
authors.initials: B
authors.lastname: Lenormand
authors.forename: Marc
authors.initials: M
authors.lastname: Vasse
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D001779:Blood Coagulation Factors / Q000032:analysis*; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010743:Phospholipids / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020246:Venous Thrombosis / Q000097:blood* / Q000188:drug therapy* / Q000453:epidemiology; D014812:Vitamin K / Q000037:antagonists & inhibitors*; D055815:Young Adult
chemical_list: D000925:Anticoagulants; D001779:Blood Coagulation Factors; D010743:Phospholipids; D014812:Vitamin K