title: The effect of shiga toxin on weibel-palade bodies in primary human endothelial cells.
abstract: OBJECTIVE
  Diarrhea-associated hemolytic uremic syndrome is associated with the presence of Shiga toxin (Stx1, Stx2 and several variants) in the circulation. The aim of this study is to examine the possible triggering effect of Stx1 on the exocytosis of Weibel-Palade bodies (WPbs).
  
  
  METHODS
  Cultured human umbilical venous endothelial cells (HUVECs) and glomerular microvascular endothelial cells (GMVECs) were stimulated by thrombin and Stx1 in both static and flowing conditions. The amount of secreted von Willebrand factor (VWF) in the supernatant as well as the remaining intracellular fraction was determined.
  
  
  RESULTS
  In HUVECs and in 2 out of 4 GMVECs, the stimulation of Stx1 in flow at 1 dyne/cm(2) resulted in a decrease of intracellular VWF. This is contrary to the results of Stx1 applied in static conditions. At a higher flow rate of 5 dyne/cm(2), no effect in GMVECs was observed.
  
  
  CONCLUSIONS
  Stx1 can contribute, via an effect on WPbs, to the exocytosis of WPbs in flow conditions in HUVECs and probably in GMVECs. This results in the release of VWF, suggesting an initiating role of the coagulation system in the pathogenesis.
authors.affiliation: Department of Paediatric Nephrology, The Netherlands.
authors.forename: Joyce
authors.initials: J
authors.lastname: Geelen
authors.affiliation: Department of Plasma Proteins, Sanquin Research, Amsterdam, The Netherlands ; Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands.
authors.forename: Maartje
authors.initials: M
authors.lastname: van den Biggelaar
authors.affiliation: Central Hematology Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: Linssen
authors.affiliation: Department of Paediatric Nephrology, The Netherlands.
authors.forename: Thea
authors.initials: T
authors.lastname: van der Velden
authors.affiliation: Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands.
authors.forename: Koen
authors.initials: K
authors.lastname: Mertens
authors.affiliation: Department of Paediatric Nephrology, The Netherlands.
authors.forename: Leo
authors.initials: L
authors.lastname: Monnens
keywords: Endothelial cells; Shiga toxin; Weibel-Palade bodies; von Willebrand factor