Effects of the biliopancreatic diversion on energy balance in the rat

Abstract

Objective: This study was carried out to determine the effects of the biliopancreatic diversion (BPD), a bariatric surgery applied to the treatment of morbidly obese humans, on energy balance in rats. Methods: BPD was performed on a group of male Wistar rats. Body weight and food intake were measured daily throughout the study. Feces were also collected to assess energy losses and the determination of digestible energy. Energy expenditure and body composition were also determined for the 50-day length of the protocol. On the day of killing, the brain, the entire intestinal tract and white and brown adipose tissues were collected and weighed. Expression of neuropeptide Y (NPY) and agouti-related protein (AgRP) in the ARC nucleus were assessed by in situ hybridization. Results: Marked changes in the regulation of energy balance were observed in the BPD-operated rats. A decrease in digestible energy and food intake coupled with an increase in the fecal energy density and protein fecal energy led to an important weight loss in the BPD-operated rats. This weight loss was observed in the loss of fat mass (specifically the white epididymal, inguinal, retroperitoneal and brown adipose tissues). The rats modified their food intake pattern to be able to potentially eat more during the entire day. An increase in the surfaces of all intestinal structures (muscular and mucosal layers) was observed in the BPDoperated rats. The NPY and AgRP expression in the brain were both shown to be greater in the BPD-operated rats than in the control animals. At the beginning of the study, the surgery led to an energy expenditure decrease, which, however, did not persist throughout the study despite the fact that BPD-operated rats exhibited persistent lower fat free masses. Conclusion: BPD led to a noticeable reduction in weight and fat gains in rats, which was in large part owing to a decrease in digestible energy intake led to by the gastrectomy, the intestinal malabsorption inherent to the surgery and to potentially a thermogenesis stimulation that occurred in the second end of the study. The reduction in energy gain occurs despite adaptations to thwart the intestinal malabsorption and the hunger signals from the central nervous system.

Gastrointestinal hormones, energy balance and bariatric surgery

“…35 The gut is metabolically very active and gut hypertrophy may hence explain a higher energy requirement that contributes to body weight loss. 9,37,38 These findings are in line with previous reports demonstrating a reduced body weight without decreased food intake or malabsorption, but increased energy expenditure after GBP in rats. 39,40 Furthermore, Stylopoulos et al 41 described a 19% increase in total and a 31% increase in resting energy expenditure in rats after GBP operation.…”

RIP140 Gene and Protein Expression Levels are Downregulated in Visceral Adipose Tissue in Human Morbid Obesity

“…However, after biliopancreatic diversion (BPD), energy expenditure studied at different time-points has been observed to be significantly higher than that of nonobese controls [41]. Moreover, in rat models, it has been shown that the BPD induces a negative energy balance [42,43]. It has been recently shown that acute deficiency of RIP140 results in an inhibition of the proinflammatory program in macrophages, which would likely include those infiltrating adipose tissue [44].…”

Meal patterns, satiety, and food choice in a rat model of Roux-en-Y gastric bypass surgery

“…This likely reflects adaptive changes in the Roux limb (30), minimizing the negative impact of large liquid meals.…”

“…Compared with sham controls, these rats ate significantly less and lost significant body weight and fat tissue over 7 wk, with only an initial decrease in energy expenditure. Hypotha-lamic neuropeptide Y and agouti-related protein gene expression were significantly increased at the end of the study (30). Furthermore, jejunoileal bypass and biliopancreatic diversion surgery in male Wistar rats with no reduction in stomach size significantly decreased food intake and body weight and increased fasting plasma levels of both PYY and GLP-1 over a period of 28 days (4,21).…”

“…A different surgical approach used vertical sleeve gastrectomy and a clip on the proximal duodenum with the cut jejunum anastomosed to the proximal stump of the duodenum (30). Compared with sham controls, these rats ate significantly less and lost significant body weight and fat tissue over 7 wk, with only an initial decrease in energy expenditure.…”