title: Metabolic and hormonal changes after laparoscopic Roux-en-Y gastric bypass and sleeve gastrectomy: a randomized, prospective trial.
abstract: BACKGROUND
  The mechanisms of amelioration of glycemic control early after laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) are not fully understood.
  
  
  METHODS
  In this prospective, randomized 1-year trial, outcomes of LRYGB and LSG patients were compared, focusing on possibly responsible mechanisms. Twelve patients were randomized to LRYGB and 11 to LSG. These non-diabetic patients were investigated before and 1 week, 3 months, and 12 months after surgery. A standard test meal was given after an overnight fast, and blood samples were collected before, during, and after food intake for hormone profiles (cholecystokinin (CCK), ghrelin, glucagon-like peptide 1 (GLP-1), peptide YY (PYY)).
  
  
  RESULTS
  In both groups, body weight and BMI decreased markedly and comparably leading to an identical improvement of abnormal glycemic control (HOMA index). Post-surgery, patients had markedly increased postprandial plasma GLP-1 and PYY levels (p < 0.05) with ensuing improvement in glucose homeostasis. At 12 months, LRYGB ghrelin levels approached preoperative values. The postprandial, physiologic fluctuation returned, however, while LSG ghrelin levels were still markedly attenuated. One year postoperatively, CCK concentrations after test meals increased less in the LRYGB group than they did in the LSG group, with the latter showing significantly higher maximal CCK concentrations (p < 0.012 vs. LRYGB).
  
  
  CONCLUSIONS
  Bypassing the foregut is not the only mechanism responsible for improved glucose homeostasis. The balance between foregut (ghrelin, CCK) and hindgut (GLP-1, PYY) hormones is a key to understanding the underlying mechanisms.
authors.affiliation: Department of Surgery, St Claraspital, 4016 Basel, Switzerland. Ralph.Peterli@Claraspital.ch
authors.forename: Ralph
authors.initials: R
authors.lastname: Peterli
authors.forename: Robert E
authors.initials: RE
authors.lastname: Steinert
authors.forename: Bettina
authors.initials: B
authors.lastname: Woelnerhanssen
authors.forename: Thomas
authors.initials: T
authors.lastname: Peters
authors.forename: Caroline
authors.initials: C
authors.lastname: Christoffel-Courtin
authors.forename: Markus
authors.initials: M
authors.lastname: Gass
authors.forename: Beatrice
authors.initials: B
authors.lastname: Kern
authors.forename: Markus
authors.initials: M
authors.lastname: von Fluee
authors.forename: Christoph
authors.initials: C
authors.lastname: Beglinger
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D002766:Cholecystokinin / Q000097:blood; D005260:Female; D015390:Gastric Bypass; D005768:Gastrointestinal Hormones / Q000097:blood*; D015391:Gastroplasty; D054439:Ghrelin / Q000097:blood; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D010535:Laparoscopy; D008297:Male; D009767:Obesity, Morbid / Q000097:blood* / Q000601:surgery; D019894:Peptide YY / Q000097:blood; D019518:Postprandial Period; D011446:Prospective Studies; D015431:Weight Loss
chemical_list: D001786:Blood Glucose; D002766:Cholecystokinin; D005768:Gastrointestinal Hormones; D054439:Ghrelin; D052216:Glucagon-Like Peptide 1; D006442:Glycated Hemoglobin; D019894:Peptide YY; C517652:hemoglobin A1c protein, human