title: Development of a humanized in vitro blood-brain barrier model to screen for brain penetration of antiepileptic drugs.
abstract: OBJECTIVE
  A biotechnologic breakthrough for the study of drug permeability across the blood-brain barrier (BBB) would be the use of a reproducible in vitro model that recapitulates the functional, structural, and pathologic properties of the BBB in situ. We developed a humanized dynamic in vitro BBB model (DIV-BBB) based on cocultures of human microvascular endothelial cells (HBMECs) from "normal" and drug-resistant epileptic brain tissue with human brain astrocytes (HAs) from epilepsy patients or controls.
  
  
  METHODS
  HBMECs and HAs were cocultured for 28 days in polypropylene capillaries. HBMECs were exposed to physiologic levels of shear stress generated by intraluminal flow. Permeability to [3H]sucrose, [14C]phenytoin, and [14C]diazepam was measured in control and drug-resistant DIV-BBB with and without pretreatment with the MDR1 inhibitor XR9576. BBB integrity was monitored by transendothelial electrical resistance measurements (TEERs). Cell growth and viability were assessed by measurement of glucose consumption and lactate production.
  
  
  RESULTS
  PSucrose and TEER values did not depend on the origin of the endothelium used (epileptic or normal). PPhenytoin was 10-fold less (1.54 x 10(-6) cm/s) in drug-resistant BBB models than in controls (1.74 x 10(-5) cm/s). MDR1 blockade with XR9576 was effective (3.5-fold increase) only in drug-resistant cultures. PDiazepam in control and drug-resistant DIV-BBB was not affected by XR9576 and did not depend on the epileptic or control origin of endothelia. The overall contribution of epileptic glia to pharmacoresistance was negligible.
  
  
  CONCLUSIONS
  These results show that, for the substances used, the humanized DIV-BBB recapitulates the physiologic permeability properties of the BBB in vivo and is also capable of mimicking a drug-resistant BBB phenotype.
authors.affiliation: Center for Cerebrovascular Research, Cleveland, Ohio, USA.
authors.forename: Luca
authors.initials: L
authors.lastname: Cucullo
authors.forename: Mohammed
authors.initials: M
authors.lastname: Hossain
authors.forename: Ed
authors.initials: E
authors.lastname: Rapp
authors.forename: Toby
authors.initials: T
authors.lastname: Manders
authors.forename: Nicola
authors.initials: N
authors.lastname: Marchi
authors.forename: Damir
authors.initials: D
authors.lastname: Janigro
mesh_terms: D000927:Anticonvulsants / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001253:Astrocytes / Q000378:metabolism / Q000502:physiology; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D001921:Brain / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003975:Diazepam / Q000378:metabolism; D004353:Drug Evaluation, Preclinical; D018432:Drug Resistance, Multiple / Q000502:physiology*; D017097:Electric Impedance; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D004827:Epilepsy / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008959:Models, Neurological; D010539:Permeability / Q000187:drug effects; D010672:Phenytoin / Q000378:metabolism; D011804:Quinolines / Q000494:pharmacology; D033081:Shear Strength; D013395:Sucrose / Q000378:metabolism; D014316:Tritium
chemical_list: D000927:Anticonvulsants; D011804:Quinolines; D014316:Tritium; D013395:Sucrose; D010672:Phenytoin; C402343:tariquidar; D003975:Diazepam