title: PP009. Hypoxia alters syncytiotrophoblastic microparticles (STBM)-related coagulation capacities.
abstract: BACKGROUND
  Endothelial dysfunction is thought to be the cause of preeclampsia (PE) symptoms. Severe forms of PE are correlated to the release of syncytiotrophoblastic microparticles (STBM), which triggers inflammatory processes on the endothelium. The thrombogenic potential of STBMs is not well characterized. We investigated the pro-coagulant activity of STBMs.
  
  
  METHODS
  STBMs were derived from placentae perfused under norm- and hypoxic conditions and quantified with our house-"ELISA". Surface phospholipid-dependent thrombin formation of microparticles was determined with a commercial ELISA. Rate and absolute platelet aggregation in platelet-rich plasma (PRP), while fibrin production in platelet free plasma, was measured in absence and presence of STBMs using a PAP-4 aggregometer.
  
  
  RESULTS
  STBM concentration and STBM-induced thrombin formation is stable under normoxic and elevated under hypoxic conditions. STBMs derived from hypoxic placentae increase the rate of fibrinogenesis. Maximum platelet aggregation is stable under normoxic, while highly variable under hypoxic conditions. STBMs of hypoxic placentae cannot alter the rate of platelet aggregation, while normoxic STBMs adjust the rate according to need.
  
  
  CONCLUSIONS
  Hypoxia negatively affects fibrinogenesis and the platelet aggregation-modulating effects of STBMs, which might be due to a phenotype alteration. All observed results may contribute to the impaired microcirculation seen in PE.
authors.forename: Claudia
authors.initials: C
authors.lastname: Göhner
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schlembach
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Schleussner
authors.forename: Udo R
authors.initials: UR
authors.lastname: Markert
authors.forename: Justine S
authors.initials: JS
authors.lastname: Fitzgerald