title: Lipopolysaccharide-induced blood-brain barrier disruption: roles of cyclooxygenase, oxidative stress, neuroinflammation, and elements of the neurovascular unit.
abstract: BACKGROUND
  Disruption of the blood-brain barrier (BBB) occurs in many diseases and is often mediated by inflammatory and neuroimmune mechanisms. Inflammation is well established as a cause of BBB disruption, but many mechanistic questions remain.
  
  
  METHODS
  We used lipopolysaccharide (LPS) to induce inflammation and BBB disruption in mice. BBB disruption was measured using (14)C-sucrose and radioactively labeled albumin. Brain cytokine responses were measured using multiplex technology and dependence on cyclooxygenase (COX) and oxidative stress determined by treatments with indomethacin and N-acetylcysteine. Astrocyte and microglia/macrophage responses were measured using brain immunohistochemistry. In vitro studies used Transwell cultures of primary brain endothelial cells co- or tri-cultured with astrocytes and pericytes to measure effects of LPS on transendothelial electrical resistance (TEER), cellular distribution of tight junction proteins, and permeability to (14)C-sucrose and radioactive albumin.
  
  
  RESULTS
  In comparison to LPS-induced weight loss, the BBB was relatively resistant to LPS-induced disruption. Disruption occurred only with the highest dose of LPS and was most evident in the frontal cortex, thalamus, pons-medulla, and cerebellum with no disruption in the hypothalamus. The in vitro and in vivo patterns of LPS-induced disruption as measured with (14)C-sucrose, radioactive albumin, and TEER suggested involvement of both paracellular and transcytotic pathways. Disruption as measured with albumin and (14)C-sucrose, but not TEER, was blocked by indomethacin. N-acetylcysteine did not affect disruption. In vivo, the measures of neuroinflammation induced by LPS were mainly not reversed by indomethacin. In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes.
  
  
  CONCLUSIONS
  The BBB is relatively resistant to LPS-induced disruption with some brain regions more vulnerable than others. LPS-induced disruption appears is to be dependent on COX but not on oxidative stress. Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.
authors.affiliation: Geriatric Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. wabanks1@uw.edu.|Division of Gerontology and Geriatric Medicine, Department of Internal Medicine, University of Washington School of Medicine, Seattle, WA, USA. wabanks1@uw.edu.
authors.forename: William A
authors.initials: WA
authors.lastname: Banks
authors.affiliation: University of Washington School of Medicine, Seattle, WA, USA. amg44@u.washington.edu.
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Gray
authors.affiliation: Geriatric Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. merick@dental.upenn.edu.|Division of Gerontology and Geriatric Medicine, Department of Internal Medicine, University of Washington School of Medicine, Seattle, WA, USA. merick@dental.upenn.edu.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Erickson
authors.affiliation: Geriatric Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. therese.s.salameh@gmail.com.
authors.forename: Therese S
authors.initials: TS
authors.lastname: Salameh
authors.affiliation: Division of Gerontology and Geriatric Medicine, Department of Internal Medicine, University of Washington School of Medicine, Seattle, WA, USA. damodm@u.washington.edu.
authors.forename: Mamatha
authors.initials: M
authors.lastname: Damodarasamy
authors.affiliation: Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA. nsheibanikar@wisc.edu.
authors.forename: Nader
authors.initials: N
authors.lastname: Sheibani
authors.affiliation: Mental Health Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. james64@u.washington.edu.
authors.forename: James S
authors.initials: JS
authors.lastname: Meabon
authors.affiliation: Geriatric Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. emilywing@gmail.com.
authors.forename: Emily E
authors.initials: EE
authors.lastname: Wing
authors.affiliation: Geriatric Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. yoichi51@hotmail.com.|Division of Gerontology and Geriatric Medicine, Department of Internal Medicine, University of Washington School of Medicine, Seattle, WA, USA. yoichi51@hotmail.com.|Department of Neurosurgery, University of Nagasaki, Nagasaki, Japan. yoichi51@hotmail.com.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Morofuji
authors.affiliation: Geriatric Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. dgcook@u.washington.edu.
authors.forename: David G
authors.initials: DG
authors.lastname: Cook
authors.affiliation: Division of Gerontology and Geriatric Medicine, Department of Internal Medicine, University of Washington School of Medicine, Seattle, WA, USA. mjr@u.washington.edu.
authors.forename: May J
authors.initials: MJ
authors.lastname: Reed
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D002461:Cell Line, Transformed; D018920:Coculture Techniques; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D007249:Inflammation / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism; D018836:Inflammation Mediators / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000633:toxicity*; D008297:Male; D051379:Mice; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000502:physiology*
chemical_list: D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D011451:Prostaglandin-Endoperoxide Synthases