title: The potential of volatile organic compounds for the detection of active disease in patients with ulcerative colitis.
abstract: To optimise treatment of ulcerative colitis (UC), patients need repeated assessment of mucosal inflammation. Current non-invasive biomarkers and clinical activity indices do not accurately reflect disease activity in all patients and cannot discriminate UC from non-UC colitis. Volatile organic compounds (VOCs) in exhaled air could be predictive of active disease or remission in Crohn's disease.
  
  
  
  To investigate whether VOCs are able to differentiate between active UC, UC in remission and non-UC colitis.
  
  
  
  UC patients participated in a 1-year study. Clinical activity index, blood, faecal and breath samples were collected at each out-patient visit. Patients with clear defined active faecal calprotectin >250 μg/g and inactive disease (Simple Clinical Colitis Activity Index <3, C-reactive protein <5 mg/L and faecal calprotectin <100 μg/g) were included for cross-sectional analysis. Non-UC colitis was confirmed by stool culture or radiological evaluation. Breath samples were analysed by gas chromatography time-of-flight mass spectrometry and kernel-based method to identify discriminating VOCs.
  
  
  
  In total, 72 UC (132 breath samples; 62 active; 70 remission) and 22 non-UC-colitis patients (22 samples) were included. Eleven VOCs predicted active vs. inactive UC in an independent internal validation set with 92% sensitivity and 77% specificity (AUC 0.94). Non-UC colitis patients could be clearly separated from active and inactive UC patients with principal component analysis.
  
  
  
  Volatile organic compounds can accurately distinguish active disease from remission in UC and profiles in UC are clearly different from profiles in non-UC colitis patients. VOCs have demonstrated potential as new non-invasive biomarker to monitor inflammation in UC.
authors.affiliation: Department of Pharmacology and Toxicology, NUTRIM School for Nutrition, and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Smolinska
authors.affiliation: Department of Gastroenterology and Hepatology, NUTRIM School for Nutrition, and Translational Research in Metabolism, Maastricht University Medical Center+, Maastricht, The Netherlands.|Department of Gastroenterology, Amphia Hospital, Breda, The Netherlands.
authors.forename: A G L
authors.identifier: 0000-0002-2329-9995
authors.initials: AG
authors.lastname: Bodelier
authors.affiliation: Department of Pharmacology and Toxicology, NUTRIM School for Nutrition, and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: Dallinga
authors.affiliation: Department of Gastroenterology and Hepatology, NUTRIM School for Nutrition, and Translational Research in Metabolism, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: A A M
authors.initials: AA
authors.lastname: Masclee
authors.affiliation: Department of Gastroenterology and Hepatology, NUTRIM School for Nutrition, and Translational Research in Metabolism, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: D M
authors.initials: DM
authors.lastname: Jonkers
authors.affiliation: Department of Pharmacology and Toxicology, NUTRIM School for Nutrition, and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands.
authors.forename: F-J
authors.initials: FJ
authors.lastname: van Schooten
authors.affiliation: Department of Gastroenterology and Hepatology, NUTRIM School for Nutrition, and Translational Research in Metabolism, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: M J
authors.initials: MJ
authors.lastname: Pierik
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D001944:Breath Tests; D002097:C-Reactive Protein / Q000032:analysis; D003092:Colitis / Q000097:blood / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D005243:Feces / Q000737:chemistry; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D012680:Sensitivity and Specificity; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex; D055549:Volatile Organic Compounds; D002097:C-Reactive Protein