title: Altered bile acid metabolism in patients with constipation-predominant irritable bowel syndrome and functional constipation.
abstract: OBJECTIVE
  Bile acids are derived from cholesterol and are potent physiological laxatives. The aim of this study was to investigate whether bile acid synthesis is altered in constipation.
  
  
  METHODS
  Female patients with constipation (23 IBS-C, 4 functional constipation (FC)) were studied and compared with non-constipated subjects (16 IBS-D, 20 healthy women). Body mass index (BMI), blood lipids, lanosterol, sitosterol, colonic transit (oro-anal transit time (OATT), reference < or =4.3 days) and stool frequency were measured. C4 (7-alpha-hydroxy-4-cholesten-3-one) levels reflecting bile acid synthesis were measured at 0800 h and 1300 h.
  
  
  RESULTS
  When all the groups of constipated and non-constipated subjects were compared, it was found that only stool frequency and OATT differed between groups (p <0.001). When constipated patients were categorized according to OATT, absence of the usual C4 increase at lunchtime was noted in 82% of patients with delayed OATT compared with 17% in subjects with normal OATT (p <0.001). Symptom severity did not differ between groups. A subset of the patients with severely delayed OATT had markedly elevated C4 levels.
  
  
  CONCLUSIONS
  Patients with IBS-C and FC have marked changes in bile acid synthesis in relation to colonic transit. The diurnal rhythm is altered in the slow transit colon when there is no C4 peak at lunchtime. Alterations in bile acid metabolism may be implicated in the pathophysiology of constipation.
authors.affiliation: Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden. hasse.abrahamsson@medic.gu.se
authors.forename: Hasse
authors.initials: H
authors.lastname: Abrahamsson
authors.forename: Ann-Margret
authors.initials: AM
authors.lastname: Ostlund-Lindqvist
authors.forename: Ralf
authors.initials: R
authors.lastname: Nilsson
authors.forename: Magnus
authors.initials: M
authors.lastname: Simrén
authors.forename: Per-Göran
authors.initials: PG
authors.lastname: Gillberg
mesh_terms: D000328:Adult; D001647:Bile Acids and Salts / Q000378:metabolism*; D003248:Constipation / Q000503:physiopathology*; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000503:physiopathology*; D008875:Middle Aged
chemical_list: D001647:Bile Acids and Salts