A Large Animal Survival Model to Evaluate Bariatric Surgery Mechanisms

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 mechan-isms is incomplete, in part because of limitations in relevant bariatric-surgery animal models, spe-cifically the lack of naturally insulin-resistant large animals. With overfeeding, Ossabaw swine de-velop a robust metabolic syndrome, and may be suitable for studying post-surgical physiology. Whe-ther 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 resis-tance. These animals were assigned to RYGB (n = 8), RYGB with vagotomy (RYGB-V, n = 5), gastro-jejunostomy (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 re-ported. 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 weigh