title: High prevalence of abnormal gastrointestinal permeability in moderate-severe asthma.
abstract: OBJECTIVE
  Abnormal gastrointestinal permeability (GIP) has been implicated in a number of diseases, including chronic intestinal inflammatory disorders such as Crohn's as well as non-intestinal immunologic diseases such as diabetes and multiple sclerosis. Although evidence in the literature demonstrates mucosal abnormalities of the digestive barrier in asthma, previous studies have assessed only colonic permeability, while ignoring the mucosal-associated lymphoid tissue (MALT) rich areas of the small intestine. Alterations in GIP may lead to increased entry of allergenic proteins from the gut lumen into the systemic circulation, thus priming and activating the adaptive immune system and leading to inappropriate allergen sensitization and/or deregulated extra-intestinal inflammation. This study examines GIP in adults with moderate to severe asthma.
  
  
  METHODS
  Patients ingested a mixed-sugar solution and urine was collected. GIP was assayed using high-performance liquid chromatography. Demographics, atopy (assessed by allergen skin testing) and sputum cell counts were also assessed.
  
  
  RESULTS
  Fourteen patients with moderate to severe asthma were studied, half of whom were found to have abnormal GIP. Abnormal GIP did not correlate with sputum cell counts and there was no apparent association between atopy and intestinal permeability.
  
  
  CONCLUSIONS
  This study demonstrated our ability to identify abnormal GIP in the MALT-rich, immunogenic small intestine of patients with asthma. The absence of a correlation between airway inflammation and increased GIP suggests that these two parameters are not causally linked, but rather define distinct entities that could separately or sequentially be involved with the development and propagation of asthma over time.
authors.forename: John
authors.initials: J
authors.lastname: Walker
authors.forename: Levinus
authors.initials: L
authors.lastname: Dieleman
authors.forename: Dennell
authors.initials: D
authors.lastname: Mah
authors.forename: Kyungran
authors.initials: K
authors.lastname: Park
authors.forename: Jon
authors.initials: J
authors.lastname: Meddings
authors.affiliation: . dilini@ualberta.ca.
authors.forename: Dilini
authors.initials: D
authors.lastname: Vethanayagam
mesh_terms: D000328:Adult; D001249:Asthma / Q000378:metabolism* / Q000503:physiopathology*; D005260:Female; D041981:Gastrointestinal Tract / Q000378:metabolism* / Q000503:physiopathology*; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology; D008297:Male; D008875:Middle Aged