title: Enhanced fasting and post-prandial plasma bile acid responses after Roux-en-Y gastric bypass surgery.
abstract: OBJECTIVE
  Exogenous bile acid (BA) administration is associated with beneficial metabolic effects very similar to those seen after Roux-en-Y gastric bypass (RYGB) surgery. Re-routing of bile into a biliopancreatic limb with simultaneous exclusion of food occurs after RYGB, with subsequent increased fasting plasma BAs. The study assessed fasting and post-prandial plasma BA response before and 15 months after RYGB.
  
  
  METHODS
  The prospective study recruited 63 obese individuals (43 females), aged 43 (36-56) [median (IQR)] years. Blood samples were collected before and every 30 min for 120 min after a standard 400 kcal meal. Fasting and post-prandial plasma BAs, glucagons like peptide-1 (GLP-1), -tyrosine (PYY), fasting C-reactive protein (CRP), glucose and insulin were measured and homeostasis model assessment-insulin resistance (HOMA-IR) was calculated.
  
  
  RESULTS
  Following RYGB, body mass index, CRP, fasting glucose and HOMA-IR decreased; 43.7 (39.3-49.2) kg/m(2) to 29.2 (25.1-35.0) kg/m(2), 7.9 (4.1-11.9) mg/L to 0.4 (0.2-1.0) mg/L, 5.5 (5.0-6.0) mmol/L to 4.6 (4.3-4.9) mmol/L and 5.9 (3.5-9.2) to 1.7 (1.1-2.2), respectively, all P < 0.001. Fasting total BAs, GLP-1 and PYY increased after RYGB; 1.69 (0.70-2.56) µmol/L to 2.43 (1.23-3.82) µmol/L (P = 0.02), 6.8 (1.5-15.3) pmol/L to 17.1 (12.6-23.9) pmol/L (P < 0.001) and 4.0 (1.0-7.1) pmol/L to 15.2 (10.0-28.3) pmol/L (P < 0.001), respectively. The area under the curve for post-prandial total BAs, total glycine-conjugated BAs, GLP-1 and PYY were greater after RYGB; 486 (312-732) µmol/L/min versus 1012 (684-1921) µmol/L/min, 315 (221-466) µmol/L/min versus 686 (424-877) µmol/L/min, 3679 (3162-4537) pmol/L/min versus 5347 (4727-5781) pmol/L/min and 1887 (1423-2092) pmol/L/min versus 3296 (2534-3834) pmol/L/min, respectively, all P < 0.0001.
  
  
  CONCLUSIONS
  Weight loss following RYGB is associated with an increase in post-prandial plasma BA response due to larger amounts of glycine-conjugated BAs. This suggests up regulation of BA production and conjugation after RYGB.
authors.affiliation: Department of Gastrosurgical Research and Education, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital , Sweden.
authors.forename: Malin
authors.initials: M
authors.lastname: Werling
authors.forename: Royce P
authors.initials: RP
authors.lastname: Vincent
authors.forename: Gemma F
authors.initials: GF
authors.lastname: Cross
authors.forename: Hanns-Ulrich
authors.initials: HU
authors.lastname: Marschall
authors.forename: Lars
authors.initials: L
authors.lastname: Fändriks
authors.forename: Hans
authors.initials: H
authors.lastname: Lönroth
authors.forename: David R
authors.initials: DR
authors.lastname: Taylor
authors.forename: Jamshid
authors.initials: J
authors.lastname: Alaghband-Zadeh
authors.forename: Torsten
authors.initials: T
authors.lastname: Olbers
authors.forename: Carel W
authors.initials: CW
authors.lastname: Le Roux
mesh_terms: D000328:Adult; D001646:Bile / Q000378:metabolism*; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism; D015331:Cohort Studies; D005215:Fasting / Q000097:blood*; D005260:Female; D015390:Gastric Bypass; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000601:surgery; D019518:Postprandial Period / Q000502:physiology*; D013997:Time Factors; D015431:Weight Loss / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D007328:Insulin; D052216:Glucagon-Like Peptide 1; D002097:C-Reactive Protein