TITLE:
A Large Animal Survival Model to Evaluate Bariatric Surgery Mechanisms
AUTHORS:
Vlad V. Simianu, Jonathan G. Sham, Andrew S. Wright, Skye D. Stewart, Mouhamad Alloosh, Michael Sturek, David E. Cummings, David R. Flum
KEYWORDS:
Ossabaw, Bariatric Surgery, Roux-en-Y Gastric Bypass, Weight Loss, Metabolic Syndrome
JOURNAL NAME:
Surgical Science,
Vol.6 No.8,
July
24,
2015
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.