title: Increased colonic bile acid exposure: a relevant factor for symptoms and treatment in IBS.
abstract: OBJECTIVE
  Bile acids may play a role in the pathogenesis of IBS. We investigated the potential effects of bile acids entering the colon and its role in the symptom pattern in IBS.
  
  
  METHODS
  We measured 75Se-labelled homocholic acid-taurine (75SeHCAT) retention, and serum levels of 7α-hydroxy-4-cholesten-3-one (C4) and fibroblast growth factor (FGF) 19 in patients with IBS (n=141) and control subjects (75SeHCAT n=29; C4 and FGF19 n=435). In patients with IBS stool frequency and form, as well as GI symptom severity were registered, and in a proportion of patients colonic transit time and rectal sensitivity were measured (n=66). An 8-week open-label treatment with colestipol was offered to patients with 75SeHCAT <20%, and the effect of treatment was evaluated with IBS severity scoring system and adequate relief of IBS symptoms.
  
  
  RESULTS
  Compared with controls, patients with IBS had lower 75SeHCAT values (p=0.005), higher C4c levels (C4 corrected for cholesterol) (p<0.001), but similar FGF19 levels. Abnormal 75SeHCAT retention (<10%) was seen in 18% of patients, whereas 23% had elevated C4c levels. Patients with IBS with 75SeHCAT retention <10% had more frequent stools, accelerated colonic transit time, rectal hyposensitivity, a higher body mass index, higher C4c and lower FGF19 levels. Colestipol treatment improved IBS symptoms (IBS severity scoring system 220±109 vs. 277±106; p<0.01), and 15/27 patients fulfilled criteria for treatment response (adequate relief ≥50% of weeks 5-8).
  
  
  CONCLUSIONS
  Increased colonic bile acid exposure influences bowel habit and colonic transit time in patients with IBS. A high response rate to open label treatment with colestipol supports this, but placebo-controlled studies are warranted.
authors.affiliation: Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Antal
authors.initials: A
authors.lastname: Bajor
authors.affiliation: Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden University of Gothenburg Centre for Person-Centred Care (GPCC), Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Hans
authors.initials: H
authors.lastname: Törnblom
authors.affiliation: Department of Medicine, Metabolism Unit, Center for Endocrinology, Metabolism, and Diabetes, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden Molecular Nutrition Unit, Department of Biosciences and Nutrition, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Rudling
authors.affiliation: Department of Internal Medicine, Medicine and R&D Unit, Skaraborgs Hospital, Skövde, Sweden.
authors.forename: Kjell-Arne
authors.initials: KA
authors.lastname: Ung
authors.affiliation: Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden University of Gothenburg Centre for Person-Centred Care (GPCC), Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Simrén
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001647:Bile Acids and Salts; D003106:Colon; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D013656:Taurocholic Acid / Q000031:analogs & derivatives; D055815:Young Adult
chemical_list: D001647:Bile Acids and Salts; D013656:Taurocholic Acid; C033638:23-seleno-25-homotaurocholic acid
keywords: Bile Acid; Irritable Bowel Syndrome