title: Weight loss induced by Roux-en-Y gastric bypass but not laparoscopic adjustable gastric banding increases circulating bile acids.
abstract: BACKGROUND
  It has been hypothesized that increased plasma bile acids (BAs) contribute to metabolic improvements after Roux-en-Y gastric bypass (RYGB) surgery by the G protein-coupled receptor TGR5-mediated effects on glucagon-like peptide-1 secretion and thyroid hormones.
  
  
  OBJECTIVE
  The objective of this study was to evaluate the importance of bariatric surgery-induced alterations in BA physiology on factors that regulate glucose homeostasis (insulin secretion and sensitivity) and energy metabolism (resting energy expenditure and thyroid hormone axis). DESIGN, PARTICIPANTS, INTERVENTION, AND MAIN OUTCOME MEASURE: Eighteen extremely obese subjects were studied before and after 20% weight loss, induced by either laparoscopic adjustable gastric banding (LAGB) (n = 10) or RYGB surgery (n = 8).
  
  
  RESULTS
  Plasma BAs more than doubled after RYGB [fasting: 1.08 (0.26-1.42) to 2.28 (1.59-3.28) μmol/L, P = .03; postprandial: 2.46 ± 1.59 to 6.00 ± 2.75 μmol/L, P = .01] but were either lower or did not change after LAGB [fasting: 1.80 (1.49-2.19) to 0.92 (0.73-1.15) μmol/L, P = .02; postprandial: 3.71 ± 2.61 to 2.82 ± 1.75 μmol/L, P = .14]. Skeletal muscle expression of TGR5 targets, Kir6.2 and cyclooxygenase IV, increased after RYGB but not LAGB. Surgery-induced changes in BAs were associated with increased peak postprandial plasma glucagon-like peptide-1 (r(2) = 0.509, P = .001) and decreased serum TSH (r(2) = 0.562, P < .001) but did not correlate with the change in insulin response to a meal (r(2) = 0.013, P = .658), insulin sensitivity (assessed as insulin stimulated glucose disposal during a hyperinsulinemic-euglycemic clamp procedure) (r(2) = 0.001, P = .995), or resting energy expenditure (r(2) = 0.004, P = .807).
  
  
  CONCLUSIONS
  Compared with LAGB, RYGB increases circulating BAs and TGR5 signaling, but this increase in BAs is not a significant predictor of changes in glucose homeostasis or energy metabolism.
authors: Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA.
authors: Rohit
authors: R
authors: Kohli
authors: David
authors: D
authors: Bradley
authors: Kenneth D
authors: KD
authors: Setchell
authors: J Christopher
authors: JC
authors: Eagon
authors: Nada
authors: N
authors: Abumrad
authors: Samuel
authors: S
authors: Klein
mesh_terms: D000328:Adult; D000713:Anastomosis, Roux-en-Y / Q000009:adverse effects / Q000379:methods; D001647:Bile Acids and Salts / Q000097:blood*; D004734:Energy Metabolism / Q000502:physiology; D005215:Fasting / Q000097:blood / Q000378:metabolism; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects / Q000379:methods; D015391:Gastroplasty / Q000379:methods; D006801:Humans; D010535:Laparoscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000378:metabolism / Q000601:surgery*; D019518:Postprandial Period / Q000502:physiology; D012146:Rest / Q000502:physiology; D015854:Up-Regulation; D015431:Weight Loss / Q000502:physiology*
chemical_list: D001647:Bile Acids and Salts