title: ATP-binding cassette transporters in immortalised human brain microvascular endothelial cells in normal and hypoxic conditions.
abstract: BACKGROUND
  Rapid reperfusion following ischemia is the most effective therapy in stroke therapy. However, the success may be compromised by ischemia & reperfusion (I/R) injury and at the human blood-brain barrier (BBB), therefore the effects on transendothelial transport are of special interest. Current studies suggest the ATP-binding cassette (ABC) transporters to be regulated upon ischemic stroke in a way that impedes the effects of drug therapy. The immortalised human brain microvascular endothelial cell line hCMEC/D3 provides most of the unique properties of the BBB with respect to transport and might be a reliable in vitro model to study transendothelial transport after I/R.
  
  
  METHODS
  We exposed hCMEC/D3 cells to 24 hours of hypoxia alone and to hypoxia followed by 60 min of reoxygenisation as an in vitro model for I/R. Western blot showed mild upregulation of hypoxia inducible factor (HIF-1α) after hypoxia alone and RNA lysates were analysed with a well-established real-time RT-PCR-based TaqMan low-density array detecting 47 of 48 known human ABC transporters.
  
  
  RESULTS
  No significant increases of ABC mRNA expression levels were detected neither in hypoxic nor in I/R samples. However, slight decrease of ABCC1 in hypoxic and I/R samples and of ABCA10 and ABCD3 in I/R samples was observed.
  
  
  CONCLUSIONS
  Our data suggests that hCMEC/D3 cell line and - at the moment - in vitro models in general are a poor basis for stroke research but may be enhanced by co-culturing more cells of the neurovascular unit inducing an overall ischemic response at the BBB.
authors.affiliation: Department of Neurology, University of Regensburg, Bezirksklinikum Regensburg, Regensburg, Germany. felix.schlachetzki@klinik.uni-regensburg.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Lindner
authors.forename: Alexander
authors.initials: A
authors.lastname: Sigrüner
authors.forename: Franziska
authors.initials: F
authors.lastname: Walther
authors.forename: Ulrich
authors.initials: U
authors.lastname: Bogdahn
authors.forename: Pierre O
authors.initials: PO
authors.lastname: Couraud
authors.forename: Gert
authors.initials: G
authors.lastname: Schmitz
authors.forename: Felix
authors.initials: F
authors.lastname: Schlachetzki