title: Nitric oxide mediates interferon-gamma-induced hyperpermeability in cultured human intestinal epithelial monolayers.
abstract: OBJECTIVE
  Incubation with interferon-gamma has been shown to increase the permeability of cultured monolayers of intestinal epithelial cells. We sought to determine whether this phenomenon is mediated, at least in part, by increased production of nitric oxide.
  
  
  METHODS
  Prospective, controlled, laboratory study. Human intestinal epithelial (Caco-2BBe) cells were grown as monolayers on permeable supports mounted in bicameral chambers. Permeability was assessed by adding fluorescein sulfonic acid (molecular weight = 478 daltons) to the apical compartment and determining the apical-to-basolateral clearance of the probe over a 24-hr period of incubation.
  
  
  METHODS
  Basic science laboratory.
  
  
  RESULTS
  The permeability of monolayers to fluorescein sulfonic acid was significantly increased after incubation in the presence of interferon-gamma (250 to 1000 U/mL). The effect of interferon-gamma on permeability was dependent on both the concentration of the cytokine and the duration of exposure to it. Concentrations of nitric oxide oxidation products, nitrite and nitrate, in incubation media were increased after exposure of cells to interferon-gamma. When intestinal epithelial (Caco-2BBe) monolayers were incubated with interferon-gamma in the presence of inhibitors of nitric oxide synthase (NG-monomethyl-L-arginine NG-nitro-L-arginine-methyl ester, or NG-nitro-L-arginine), both of the effects of the cytokine (i.e., increased epithelial permeability and increased production of nitrite/nitrate) were attenuated.
  
  
  CONCLUSIONS
  These results suggest that upregulation of nitric oxide biosynthesis plays a pivotal role in the increase in permeability of intestinal epithelial (Caco-2BBe) monolayers induced by interferon-gamma. Increased production of nitric oxide induced by proinflammatory cytokines, such as interferon-gamma, may be an important factor contributing to gut mucosal hyperpermeability in sepsis.
authors.affiliation: Department of Surgery, Beth Israel Hospital, Boston, MA 02215, USA.
authors.forename: N
authors.initials: N
authors.lastname: Unno
authors.forename: M J
authors.initials: MJ
authors.lastname: Menconi
authors.forename: M
authors.initials: M
authors.lastname: Smith
authors.forename: M P
authors.initials: MP
authors.lastname: Fink
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005452:Fluoresceins / Q000493:pharmacokinetics; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase; D009573:Nitrites / Q000378:metabolism; D011446:Prospective Studies; D011994:Recombinant Proteins; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D005452:Fluoresceins; D009566:Nitrates; D009573:Nitrites; D011994:Recombinant Proteins; C094528:fluorescein sulfonic acid; D009569:Nitric Oxide; D007371:Interferon-gamma; D007770:L-Lactate Dehydrogenase; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases