title: Small intestinal permeability is increased in diarrhoea predominant IBS, while alterations in gastroduodenal permeability in all IBS subtypes are largely attributable to confounders.
abstract: BACKGROUND
  Intestinal permeability has been studied in small groups of IBS patients with contrasting findings.
  
  
  OBJECTIVE
  To assess intestinal permeability at different sites of the GI tract in different subtypes of well-characterised IBS patients and healthy controls (HC), and to assess potential confounding factors.
  
  
  METHODS
  IBS patients and HC underwent a multi-sugar test to assess site-specific intestinal permeability. Sucrose excretion and lactulose/rhamnose ratio in 0-5 h urine indicated gastroduodenal and small intestinal permeability, respectively. Sucralose/erythritol ratio in 0-24 h and 5-24 h urine indicated whole gut and colonic permeability, respectively. Linear regression analysis was used to assess the association between IBS groups and intestinal permeability and to adjust for age, sex, BMI, anxiety or depression, smoking, alcohol intake and use of medication.
  
  
  RESULTS
  Ninety-one IBS patients, i.e. 37% IBS-D, 23% IBS-C, 33% IBS-M and 7% IBS-U and 94 HC were enrolled. Urinary sucrose excretion was significantly increased in the total IBS group [μmol, median (Q1;Q3): 5.26 (1.82;11.03) vs. 2.44 (0.91;5.85), P < 0.05], as well as in IBS-C and IBS-D vs. HC. However, differences attenuated when adjusting for confounders. The lactulose/rhamnose ratio was increased in IBS-D vs. HC [0.023 (0.013;0.038) vs. 0.014 (0.008;0.025), P < 0.05], which remained significant after adjustment for confounders. No difference was found in 0-24 and 5-24 h sucralose/erythritol ratio between groups.
  
  
  CONCLUSIONS
  Small intestinal permeability is increased in patients with IBS-D compared to healthy controls, irrespective of confounding factors. Adjustment for confounders is necessary when studying intestinal permeability, especially in a heterogeneous disorder such as IBS.
authors.affiliation: Division Gastroenterology-Hepatology, Department of Internal Medicine, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: Z
authors.initials: Z
authors.lastname: Mujagic
authors.forename: S
authors.initials: S
authors.lastname: Ludidi
authors.forename: D
authors.initials: D
authors.lastname: Keszthelyi
authors.forename: M A M
authors.initials: MA
authors.lastname: Hesselink
authors.forename: J W
authors.initials: JW
authors.lastname: Kruimel
authors.forename: K
authors.initials: K
authors.lastname: Lenaerts
authors.forename: N M J
authors.initials: NM
authors.lastname: Hanssen
authors.forename: J M
authors.initials: JM
authors.lastname: Conchillo
authors.forename: D M A E
authors.initials: DM
authors.lastname: Jonkers
authors.forename: A A M
authors.initials: AA
authors.lastname: Masclee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003967:Diarrhea / Q000378:metabolism*; D004896:Erythritol / Q000652:urine; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D043183:Irritable Bowel Syndrome / Q000378:metabolism*; D007792:Lactulose / Q000652:urine; D008297:Male; D008875:Middle Aged; D010539:Permeability; D012210:Rhamnose / Q000652:urine; D013395:Sucrose / Q000652:urine; D055815:Young Adult
chemical_list: D007792:Lactulose; D013395:Sucrose; D012210:Rhamnose; D004896:Erythritol