title: A Large Animal Survival Model to Evaluate Bariatric Surgery Mechanisms.
abstract: BACKGROUND
  The impact of Roux-en-Y gastric bypass (RYGB) on type 2 diabetes mellitus is thought to result from upper and/or lower gut hormone alterations. Evidence supporting these mechanisms is incomplete, in part because of limitations in relevant bariatric-surgery animal models, specifically the lack of naturally insulin-resistant large animals. With overfeeding, Ossabaw swine develop a robust metabolic syndrome, and may be suitable for studying post-surgical physiology. Whether bariatric surgery is feasible in these animals with acceptable survival is unknown.
  
  
  METHODS
  Thirty-two Ossabaws were fed a high-fat, high-cholesterol diet to induce obesity and insulin resistance. These animals were assigned to RYGB (n = 8), RYGB with vagotomy (RYGB-V, n = 5), gastrojejunostomy (GJ, n = 10), GJ with duodenal exclusion (GJD, n = 7), or sham operation (n = 2) and were euthanized 60 days post-operatively. Post-operative changes in weight and food intake are reported.
  
  
  RESULTS
  Survival to scheduled necropsy among surgical groups was 77%, living an average of 57 days post-operatively. Cardiac arrest under anesthesia occurred in 4 pigs. Greatest weight loss (18.0% ± 6%) and food intake decrease (57.0% ± 20%) occurred following RYGB while animals undergoing RYGB-V showed only 6.6% ± 3% weight loss despite 50.8% ± 25% food intake decrease. GJ (12.7% ± 4%) and GJD (1.2% ± 1%) pigs gained weight, but less than sham controls (13.4% ± 10%).
  
  
  CONCLUSIONS
  A survival model of metabolic surgical procedures is feasible, leads to significant weight loss, and provides the opportunity to evaluate new interventions and subtle variations in surgical technique (e.g. vagus nerve sparing) that may provide new mechanistic insights.
authors.affiliation: Departments of Surgery, University of Washington, Seattle, USA.
authors.forename: Vlad V
authors.initials: VV
authors.lastname: Simianu
authors.affiliation: Departments of Surgery, University of Washington, Seattle, USA.
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Sham
authors.affiliation: Departments of Surgery, University of Washington, Seattle, USA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Wright
authors.affiliation: Departments of Surgery, University of Washington, Seattle, USA.
authors.forename: Skye D
authors.initials: SD
authors.lastname: Stewart
authors.affiliation: Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: Mouhamad
authors.initials: M
authors.lastname: Alloosh
authors.affiliation: Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Sturek
authors.affiliation: Departments of Medicine, University of Washington, Seattle, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Cummings
authors.affiliation: Departments of Surgery, University of Washington, Seattle, USA ; Departments of Health Services, University of Washington, Seattle, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Flum
keywords: Bariatric Surgery; Metabolic Syndrome; Ossabaw; Roux-en-Y Gastric Bypass; Weight Loss