title: Human placental syncytiotrophoblast microvillous membranes impair maternal vascular endothelial function.
abstract: OBJECTIVE
  To investigate the hypothesis that, should there be an increase in deported syncytiotrophoblast microvillous membrane fragments in pre-eclampsia, it may cause maternal vascular endothelial dysfunction.
  
  
  METHODS
  Syncytiotrophoblast microvillous membrane (STBM) vesicles, prepared from normal term placentae, were perfused through small subcutaneous arteries isolated from fat biopsies obtained at caesarean section. Endothelial function of these arteries was studied by determining acetylcholine-induced relaxation after preconstriction with noradrenaline. As controls, physiological buffer or red blood cell membranes in physiological buffer were used and endothelial function similarly estimated. Transmission electron microscopy was performed on arteries after perfusion.
  
  
  METHODS
  STBM vesicles, isolated from the placentae of three healthy women undergoing elective caesarean section for reasons unrelated to pre-eclampsia, were suspended in physiological buffer. Subcutaneous fat arteries were obtained from a separate group of 13 normotensive pregnant women, also undergoing elective caesarean section at term.
  
  
  RESULTS
  Perfusion with red blood cell membranes or physiological buffer had no significant effect on the concentration dependent relaxation in arteries preconstricted with noradrenaline. However, after 2 h perfusion with STBM vesicles, arteries showed a significant reduction in relaxation to acetylcholine, indicative of altered endothelial function. Transmission electron microscopy of arteries perfused with STBM vesicles confirmed endothelial disruption.
  
  
  CONCLUSIONS
  STBM vesicle perfusion specifically altered the relaxation response of preconstricted maternal subcutaneous fat arteries to acetylcholine, suggesting an alteration in endothelial dependent relaxation. Deported microvilli may therefore be capable of producing endothelial cell damage and endothelial dysfunction observed in the maternal syndrome of pre-eclampsia.
authors.affiliation: Division of Obstetrics and Gynaecology, United Medical School of Guy's Hospital, London, UK.
authors.forename: A P
authors.initials: AP
authors.lastname: Cockell
authors.forename: J G
authors.initials: JG
authors.lastname: Learmont
authors.forename: A K
authors.initials: AK
authors.lastname: Smárason
authors.forename: C W
authors.initials: CW
authors.lastname: Redman
authors.forename: I L
authors.initials: IL
authors.lastname: Sargent
authors.forename: L
authors.initials: L
authors.lastname: Poston
mesh_terms: D001158:Arteries; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006801:Humans; D008854:Microscopy, Electron; D008871:Microvilli / Q000648:ultrastructure; D009126:Muscle Relaxation; D011225:Pre-Eclampsia / Q000473:pathology / Q000503:physiopathology; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000473:pathology / Q000503:physiopathology*; D014327:Trophoblasts / Q000502:physiology / Q000648:ultrastructure*; D014655:Vascular Resistance