title: Faecal gas analysis by electronic nose as novel, non-invasive method for assessment of active and quiescent paediatric inflammatory bowel disease: Proof of principle study.
abstract: OBJECTIVE
  Inflammatory bowel disease (IBD) and its two phenotypes ulcerative colitis (UC) and Crohn's disease (CD) are essentially assessed by endoscopy, both in initial diagnostic work-up and during follow-up. This carries a high burden, especially on paediatric patients. Faecal volatile organic compounds (VOCs) are considered potential non-invasive biomarkers for intestinal diseases linked to gut microbiota alterations. We hypothesized that faecal VOC analysis by electronic nose allows discrimination of children with CD, UC and controls during active disease and remission.
  
  
  METHODS
  Faecal VOC patterns of children with newly diagnosed IBD and controls were studied by an electronic nose (Cyranose 320®), at baseline and upon achieving remission at 6-weeks of follow-up. Disease activity was assessed by global physician's assessment, substantiated by serum C-reactive protein and faecal calprotectin. Internally cross-validated receiver-operator-characteristic curves and corresponding sensitivity and specificity for detection of IBD were calculated RESULTS: Faecal VOC profiles of patients with UC (26) and CD (29) differed from controls (28); in active disease (AUC±95% CI, p-value, sensitivity, specificity: 1.00±0.00; p<0.001, 100%, 100%) and (0.85±0.05, p<0.001, 86%, 67%) and in clinical remission (0.94±0.06, p<0.001, 94%, 94%) and (0.94±0.06, p<0.001, 94%, 94%), respectively. Furthermore, CD-patients differed from UC-patients during active disease (0.96±0.03; p<0.001, 97%, 92%), and upon achieving clinical remission (0.81±0.08, p=0.002, 88%, 72%).
  
  
  CONCLUSIONS
  Faecal VOC analysis allowed discrimination of paediatric patients with IBD from controls, both during active disease and remission. It therefore has potential as non-invasive test, in both diagnostic work-up and assessment of disease activity in IBD.
authors.affiliation: Department of Pediatric Gastroenterology, VU University Medical Centre, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands. Electronic address: t.demeij@vumc.nl.
authors.forename: Tim G J
authors.initials: TG
authors.lastname: de Meij
authors.affiliation: Department of Gastroenterology and Hepatology, VU University Medical Centre, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors.forename: Nanne K H
authors.initials: NK
authors.lastname: de Boer
authors.affiliation: Department of Pediatric Gastroenterology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Benninga
authors.affiliation: Department of Pediatric Gastroenterology, VU University Medical Centre, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors.forename: Yvette E
authors.initials: YE
authors.lastname: Lentferink
authors.affiliation: Department of Pediatric Gastroenterology, VU University Medical Centre, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors.forename: Evelien F J
authors.initials: EF
authors.lastname: de Groot
authors.affiliation: Department of Pediatric Gastroenterology, VU University Medical Centre, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors.forename: Mirjam E
authors.initials: ME
authors.lastname: van de Velde
authors.affiliation: Department of Gastroenterology and Hepatology, VU University Medical Centre, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors.forename: Adriaan A
authors.initials: AA
authors.lastname: van Bodegraven
authors.affiliation: Department of Pulmonology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Marc P
authors.initials: MP
authors.lastname: van der Schee
keywords: Biomarkers; Electronic nose; Faecal gas analysis; Flatography; Inflammatory bowel disease; Volatile organic compounds