title: Differential effects of nutritional and non-nutritional therapies on intestinal barrier function in an in vitro model.
abstract: BACKGROUND
  Diminished intestinal epithelial barrier function contributes to the pathogenesis of Crohn's disease. Clinical and experimental studies propose that increased tumor necrosis factor (TNF)-α promotes barrier dysfunction. The aim of this study was to investigate the effects of nutritional and other therapies upon intestinal barrier function in the presence of TNF-α in an in vitro model.
  
  
  METHODS
  Caco-2 monolayers were grown to confluence on membrane supports and then exposed to TNF-α in the presence of polymeric formula, hydrocortisone or infliximab. Monolayer permeability was evaluated by measuring epithelial resistance, short-circuit current and horseradish peroxidase flux in an Ussing chamber. Tight junction and myosin II regulatory light-chain kinase gene expression was analysed by real-time PCR, with protein expression and localization analysed by Western blot and immunofluorescence.
  
  
  RESULTS
  TNF-α increased monolayer permeability and diminished tight junction integrity. However both polymeric formula and infliximab completely abrogated the effects of TNF-α. These monolayers displayed unchanged permeability and tight junction integrity compared to untreated cells (media-no-TNF-α controls). In contrast, hydrocortisone only partially abrogated the effects of TNF-α, with these monolayers having increased permeability and altered tight junction integrity compared to media-no-TNF-α controls.
  
  
  CONCLUSIONS
  Both polymeric formula and infliximab completely prevent epithelial barrier dysfunction in the presence of TNF-α, whereas hydrocortisone partially prevents barrier dysfunction. These results provide evidence that superior mucosal healing can be achieved with both polymeric formula and infliximab compared to hydrocortisone.
authors.affiliation: School of Women's and Children's Health, University of New South Wales, Randwick, Sydney, NSW, Australia. lily.nahidi@student.unsw.edu.au
authors.forename: Lily
authors.initials: L
authors.lastname: Nahidi
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Day
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Lemberg
authors.forename: Steven T
authors.initials: ST
authors.lastname: Leach
mesh_terms: D000893:Anti-Inflammatory Agents / Q000008:administration & dosage; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000494:pharmacology; D015153:Blotting, Western; D018938:Caco-2 Cells; D002463:Cell Membrane Permeability / Q000502:physiology; D003424:Crohn Disease / Q000503:physiopathology / Q000628:therapy; D017097:Electric Impedance; D006801:Humans; D006854:Hydrocortisone / Q000008:administration & dosage; D066298:In Vitro Techniques; D000069285:Infliximab; D007413:Intestinal Mucosa / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D024462:Myosin Type II / Q000502:physiology; D009752:Nutritional Status; D060888:Real-Time Polymerase Chain Reaction; D019108:Tight Junctions / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
chemical_list: D000893:Anti-Inflammatory Agents; D000911:Antibodies, Monoclonal; D014409:Tumor Necrosis Factor-alpha; D000069285:Infliximab; D024462:Myosin Type II; D006854:Hydrocortisone