title: Bile composition in inflammatory bowel disease: ileal disease and colectomy, but not colitis, induce lithogenic bile.
abstract: BACKGROUND
  Inflammatory bowel disease is a risk factor for gall-bladder stones, but there is controversy about the composition of these stones and whether such patients develop lithogenic bile.
  
  
  METHODS
  In 54 gallstone-free inflammatory bowel disease patients and 13 non-inflammatory bowel disease patients with cholesterol-rich gallstones, we measured the biliary cholesterol saturation indices, nucleation times and bilirubin concentrations, and determined the bile acid composition and molecular species of phosphatidylcholine, in gall-bladder bile.
  
  
  RESULTS
  Patients with Crohn's colitis or ulcerative colitis had less saturated bile (mean cholesterol saturation index, 0.9) and longer nucleation times (median, 21 days) than those with ileal Crohn's disease (1.5; 14 days) or those who had undergone colectomy (1.6; 5 days). In patients with ileal Crohn's disease, the mean biliary bilirubin concentration was two- to three-fold higher than that in the other groups, and was associated with a decrease in the percentage of biliary deoxycholate and an increase in the percentage of ursodeoxycholate, compared with disease controls, but phosphatidylcholine species were similar.
  
  
  CONCLUSIONS
  Patients with small bowel Crohn's disease, or who have undergone colonic resection, have supersaturated bile and an increased risk of cholesterol gallstone formation. In patients with ileal disease, the presence of high biliary bilirubin concentrations and low percentage of deoxycholic acid may also favour the formation of mixed, pigment-rich, gallstones.
authors.affiliation: Gastroenterology Unit, Guy's Hospital Campus, GKT School of Medicine, London, UK. steve.pereira@uclh.org
authors.forename: S P
authors.initials: SP
authors.lastname: Pereira
authors.forename: I M
authors.initials: IM
authors.lastname: Bain
authors.forename: D
authors.initials: D
authors.lastname: Kumar
authors.forename: R H
authors.initials: RH
authors.lastname: Dowling
mesh_terms: D000328:Adult; D000368:Aged; D001646:Bile / Q000737:chemistry*; D001647:Bile Acids and Salts / Q000032:analysis; D001663:Bilirubin / Q000032:analysis; D002784:Cholesterol / Q000032:analysis; D003082:Colectomy; D003424:Crohn Disease / Q000378:metabolism* / Q000601:surgery; D003460:Crystallization; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010713:Phosphatidylcholines / Q000032:analysis
chemical_list: D001647:Bile Acids and Salts; D010713:Phosphatidylcholines; D002784:Cholesterol; D001663:Bilirubin