title: Rectal mucosal nitric oxide in differentiation of inflammatory bowel disease and irritable bowel syndrome.
abstract: OBJECTIVE
  Differentiating patients with functional bowel disorders from those with inflammatory bowel disease (IBD) can be difficult. Rectal luminal levels of nitric oxide (NO) are greatly increased in IBD. To further evaluate this disease marker, we compared NO in patients with irritable bowel syndrome (IBS) with those found in patients with active IBD and in healthy control subjects.
  
  
  METHODS
  Rectal NO was measured with chemiluminescence technique by using a tonometric balloon method in 28 healthy volunteers, 39 patients with IBS, 86 with IBD (Crohn's disease and ulcerative colitis), and 12 patients with collagenous colitis. In addition, NO was measured before and after a 4-week treatment period in patients with active ulcerative colitis and repeatedly during 2 weeks in healthy volunteers.
  
  
  RESULTS
  NO was low in healthy control subjects (median, 45; 25th-75th percentile, 34-64 parts per billion [ppb]), and variations over time were small. In IBS patients NO was slightly increased (150, 53-200 ppb; P < .001), whereas patients with active IBD or collagenous colitis had greatly increased NO levels (3475, 575-8850 ppb, and 9950, 4475-19,750 ppb, respectively; P < .001). With a cutoff level of 250 ppb, NO had a sensitivity of 95% and a specificity of 91% in discriminating between active bowel inflammation and IBS. Rectal NO correlated with disease activity in IBD and collagenous colitis and decreased markedly in IBD patients responding to anti-inflammatory treatment.
  
  
  CONCLUSIONS
  Rectal NO is a minimally invasive and rapid tool for discriminating between active bowel inflammation and IBS and a possibly useful add-on for monitoring patients with IBD.
authors.affiliation: Division of Pharmacology, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden. claudia.reinders@fyfa.ki.se
authors.forename: Claudia I
authors.initials: CI
authors.lastname: Reinders
authors.forename: Max
authors.initials: M
authors.lastname: Herulf
authors.forename: Tryggve
authors.initials: T
authors.lastname: Ljung
authors.forename: Jakob
authors.initials: J
authors.lastname: Hollenberg
authors.forename: Eddie
authors.initials: E
authors.lastname: Weitzberg
authors.forename: Jon O
authors.initials: JO
authors.lastname: Lundberg
authors.forename: Per M
authors.initials: PM
authors.lastname: Hellström
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D046729:Colitis, Collagenous / Q000378:metabolism; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D043183:Irritable Bowel Syndrome / Q000378:metabolism*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D012007:Rectum / Q000378:metabolism*; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D009569:Nitric Oxide