title: Bile Acids Increase Independently From Hypocaloric Restriction After Bariatric Surgery.
abstract: OBJECTIVE
  To measure changes in the composition of serum bile acids (BA) and the expression of Takeda G-protein-coupled receptor 5 (TGR5) acutely after bariatric surgery or caloric restriction.
  
  
  BACKGROUND
  Metabolic improvement after bariatric surgery occurs before substantial weight loss. BA are important metabolic regulators acting through the farnesoid X receptor and TGR5 receptor. The acute effects of surgery on BA and the TGR5 receptor in subcutaneous white adipose tissue (WAT) are unknown.
  
  
  METHODS
  A total of 27 obese patients with type 2 diabetes mellitus were randomized to Roux-en-Y gastric bypass (RYGB) or to hypocaloric diet (HC diet) restriction (NCT 1882036). A cohort of obese patients with and without type 2 diabetes mellitus undergoing vertical sleeve gastrectomy was also recruited (n = 12) as a comparison.
  
  
  RESULTS
  After vertical sleeve gastrectomy, the level of BA increased [total: 1.17 ± 1.56 μmol/L to 4.42 ± 3.92 μmol/L (P = 0.005); conjugated BA levels increased from 0.99 ± 1.42 μmol/L to 3.59 ± 3.70 μmol/L (P = 0.01) and unconjugated BA levels increased from 0.18 ± 0.24 μmol/L to 0.83 ± 0.70 μmol/L (P = 0.009)]. With RYGB, there was a trend toward increased BA [total: 1.37 ± 0.97 μmol/L to 3.26 ± 3.01 μmol/L (P = 0.07); conjugated: 1.06 ± 0.81 μmol/L to 2.99 ± 3.02 μmol/L (P = 0.06)]. After HC diet, the level of unconjugated BA decreased [0.92 ± 0.55 μmol/L to 0.32 ± 0.43 μmol/L (P = 0.05)]. The level of WAT TGR5 gene expression decreased after surgery, but not in HC diet. Protein levels did not change.
  
  
  CONCLUSIONS
  The levels of serum BA increase after bariatric surgery independently from caloric restriction, whereas the level of WAT TGR5 protein is unaffected.
authors.affiliation: *Department of Surgery, University of Minnesota, Minneapolis, MN†Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN‡Department of Food Science and Nutrition, University of Minnesota, Minneapolis, MN§CentraCare Bariatric Center, University of Minnesota, St. Cloud, MN.
authors.forename: Cyrus
authors.initials: C
authors.lastname: Jahansouz
authors.forename: Hongliang
authors.initials: H
authors.lastname: Xu
authors.forename: Ann V
authors.initials: AV
authors.lastname: Hertzel
authors.forename: Federico J
authors.initials: FJ
authors.lastname: Serrot
authors.forename: Nicholas
authors.initials: N
authors.lastname: Kvalheim
authors.forename: Abigail
authors.initials: A
authors.lastname: Cole
authors.forename: Anasooya
authors.initials: A
authors.lastname: Abraham
authors.forename: Girish
authors.initials: G
authors.lastname: Luthra
authors.forename: Kristin
authors.initials: K
authors.lastname: Ewing
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Leslie
authors.forename: David A
authors.initials: DA
authors.lastname: Bernlohr
authors.forename: Sayeed
authors.initials: S
authors.lastname: Ikramuddin
mesh_terms: D000328:Adult; D050110:Bariatric Surgery; D001647:Bile Acids and Salts / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000601:surgery*; D004038:Diet, Reducing; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000601:surgery*; D060888:Real-Time Polymerase Chain Reaction; D043562:Receptors, G-Protein-Coupled / Q000097:blood*
chemical_list: D001647:Bile Acids and Salts; C473772:GPBAR1 protein, human; D043562:Receptors, G-Protein-Coupled