title: Serotonin synthesis and uptake in symptomatic patients with Crohn's disease in remission.
abstract: OBJECTIVE
  Symptoms resembling irritable bowel syndrome (IBS) are reported frequently in Crohn's disease (CD) patients in remission. Studies of the mucosal content of serotonin, which is a pivotal neurotransmitter in the gut, suggest that serotonin availability is altered in IBS patients. We aimed to study the role of serotonin in the generation of IBS-like symptoms in CD patients in remission.
  
  
  METHODS
  Ileal and colonic biopsy specimens were obtained from 20 CD patients in remission, 10 with and 10 without IBS-like symptoms, and 11 healthy controls. Enterochromaffin cells were counted, and messenger RNA expression levels of tryptophan hydroxylase (TpH)-1 and serotonin reuptake transporter were determined.
  
  
  RESULTS
  The levels of mucosal serotonin reuptake transporter expression were significantly higher in the ileum than in the colon, in all groups studied (P < .02). When the ileum and colon were analyzed separately, TpH-1 expression in the colon of CD patients with IBS-like symptoms was found to be significantly higher compared with the 2 other studied groups (controls, P < .005; CD patients without IBS-like symptoms, P < .01). The number of enterochromaffin cells per gland was comparable for the patient groups in the ileum and colon.
  
  
  CONCLUSIONS
  CD patients in remission who experience IBS-like symptoms have increased mucosal TpH-1 levels in the colon, suggesting that increased serotonin biosynthesis in the colon plays a role in the generation of the symptoms.
authors.affiliation: Department of Gastroenterology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Itta M
authors.initials: IM
authors.lastname: Minderhoud
authors.forename: Bas
authors.initials: B
authors.lastname: Oldenburg
authors.forename: Marguerite E I
authors.initials: ME
authors.lastname: Schipper
authors.forename: José J M
authors.initials: JJ
authors.lastname: ter Linde
authors.forename: Melvin
authors.initials: M
authors.lastname: Samsom
mesh_terms: D000328:Adult; D002452:Cell Count; D003106:Colon / Q000473:pathology; D003113:Colonoscopy; D003424:Crohn Disease / Q000378:metabolism*; D004759:Enterochromaffin Cells / Q000166:cytology; D019858:Enteroendocrine Cells / Q000166:cytology; D005260:Female; D006801:Humans; D007082:Ileum / Q000473:pathology; D043183:Irritable Bowel Syndrome / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D012074:Remission Induction; D012701:Serotonin / Q000096:biosynthesis* / Q000378:metabolism; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism; D014365:Tryptophan Hydroxylase / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D050486:Serotonin Plasma Membrane Transport Proteins; D012701:Serotonin; D014365:Tryptophan Hydroxylase