title: Changes in bile acid composition and effect on cytolytic activity of fecal water by ursodeoxycholic acid administration: a placebo-controlled cross-over intervention trial in healthy volunteers.
abstract: BACKGROUND
  Ursodeoxycholic acid (UDCA) has been shown to affect membrane-damaging effects of bile acids in vitro and fecal bile acid composition in rats. This study evaluates the effect of UDCA on fecal bile acid composition and on cytolytic activity of fecal water in man to clarify the potential chemopreventive role of UDCA for colorectal cancer.
  
  
  METHODS
  In this placebo-controlled crossover intervention trial, the effect of 900 mg/day UDCA orally in 15 healthy volunteers was studied. At the end of each 4-week period, 72 h feces were collected. Total and individual bile acids in feces were determined by gas chromatography and soluble bile acids were analyzed by high-performance liquid chromatography. Cytolytic activity of fecal water was measured using an erythrocyte lysis assay.
  
  
  RESULTS
  In feces, the percentages of primary bile acids-cholic acid (CA) and chenodeoxycholic acid (CDCA)-and of secondary bile acid-deoxycholic acid (DCA) - decreased after supplementation with UDCA, whereas those of UDCA and LCA increased from 2.7 +/- 0.4% to 23.7 +/- 2.6%, P < 0.0001 and from 26.2 +/- 1.2% to 49.4 +/- 1.8%, P < 0.0001 respectively. The concentrations of these two bile acids in fecal water also increased after UDCA administration from 7.8 +/- 1.9 micromol/l to 47.0 +/- 6.7 micromol/l (UDCA), P < 0.0001 and from 2.5 +/- 0.6 micromol/l to 18.3 +/- 4.1 micromol/l (LCA), P < 0.002, respectively. Cytolytic activity of fecal water was not affected by UDCA.
  
  
  CONCLUSIONS
  These results do not support a protective effect of UDCA supplementation against colorectal cancer in man.
authors.affiliation: Dept of Gastroenterology, University Hospital, Groningen, The Netherlands.
authors.forename: B A P
authors.initials: BA
authors.lastname: van Gorkom
authors.forename: R
authors.initials: R
authors.lastname: van der Meer
authors.forename: W
authors.initials: W
authors.lastname: Boersma-van Ek
authors.forename: D S M L
authors.initials: DS
authors.lastname: Termont
authors.forename: E G E
authors.initials: EG
authors.lastname: de Vries
authors.forename: J H
authors.initials: JH
authors.lastname: Kleibeuker
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001647:Bile Acids and Salts / Q000737:chemistry*; D002756:Cholagogues and Choleretics / Q000494:pharmacology*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D015179:Colorectal Neoplasms / Q000209:etiology / Q000517:prevention & control; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005243:Feces / Q000737:chemistry*; D005260:Female; D006461:Hemolysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012307:Risk Factors; D014580:Ursodeoxycholic Acid / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D001647:Bile Acids and Salts; D002756:Cholagogues and Choleretics; D014580:Ursodeoxycholic Acid