Metabolic surgery: an evolution through bariatric animal models

Abstract

Metabolic surgery was developed through the application and experience gained from bariatric or weight loss procedures. Much of our knowledge from the procedures comes from the study of animal models, where they have revealed anatomic feasibility, systemic physiological elements and cellular metabolic effects. The first generation of operation included the jejunoileal bypass and partial ileal bypass that led to the development of the current procedures including Roux-en-Y gastric bypass, biliopancreatic diversion, adjustable gastric banding and sleeve gastrectomy. These operations carry significant metabolic benefits and can reduce the risk of diabetes, heart disease and cancer. Further insights from these animal models can reveal genetic, molecular and systemic effects that can enhance and develop the next generation of metabolic operations.

Metabolic surgery and cancer

“…11,58,59 Although, traditionally, surgery was considered to achieve weight loss through the malabsorption of food and restriction of stomach size, there is some discrepancy supporting the effects of stomach-pouch size or calorific malabsorption other than for a minority of procedures (such as the biliopancreatic diversion). 11,60 Surgery does, however, achieve a sustained decrease in caloric intake, 61,62 which has a long-standing association with decreased carcinogenesis in several experimental models that span over a century of research. 63,64 One study has revealed that the Roux-en-Y gastric bypass operation can decrease daily calorie intake by 1479 Kcal/day so that patients only consume 1341 Kcal/day.…”

“…Here, the surgical patients had a 5 times higher remission rate for diabetes compared with medical controls, and weight loss was the principal predictor of diabetes remission. 31,57 The mechanisms for weight loss after metabolic surgery are muiltifactorial 11,12 and include the modulation of gut hormones that lead to alterations in appetite, hunger, dietary feeding behavior, and, more recently, taste modulation in addition to alterations in metabolic rate and resting energy expenditure. 11,58,59 Although, traditionally, surgery was considered to achieve weight loss through the malabsorption of food and restriction of stomach size, there is some discrepancy supporting the effects of stomach-pouch size or calorific malabsorption other than for a minority of procedures (such as the biliopancreatic diversion).…”

“…31,57 The mechanisms for weight loss after metabolic surgery are muiltifactorial 11,12 and include the modulation of gut hormones that lead to alterations in appetite, hunger, dietary feeding behavior, and, more recently, taste modulation in addition to alterations in metabolic rate and resting energy expenditure. 11,58,59 Although, traditionally, surgery was considered to achieve weight loss through the malabsorption of food and restriction of stomach size, there is some discrepancy supporting the effects of stomach-pouch size or calorific malabsorption other than for a minority of procedures (such as the biliopancreatic diversion). 11,60 Surgery does, however, achieve a sustained decrease in caloric intake, 61,62 which has a long-standing association with decreased carcinogenesis in several experimental models that span over a century of research.…”

“…Pure bypass procedures that ''rearrange'' gastrointestinal anatomy (duodenojejunal bypass), or combination procedures with elements of both anatomical rearrangement and stomach size restriction (Rouxen-Y gastric bypass-the current gold standard metabolic operation). 12 These procedures consist of several physiological steps, the so-called BRAVE 10,11 effects: 1) bile flow alteration, 2) reduction of gastric size, 3) anatomical gut rearrangement and altered flow of nutrients, 4) vagal manipulation, and 5) enteric gut hormone modulation. It was initially hypothesized that performing gastric bypass surgery could result in biliary reflux and increased cancer risk.…”

Sleeve Gastrectomy With Modified Jejunoileal Bypass Model in Goto-Kakizaki Rats

“…19 SG has a similar hypoglycemic effect to Roux-en-Y bypass. 4 JIB was a widely performed procedure for morbid obesity during the 1970s, and it led to intestinal malabsorption for reducing weight and decreasing blood glucose; however, because of the high morbidity rates, its popularity declined, and most surgeons no longer perform the operation.…”