(DOWNLOAD) "Effects and Mechanisms of Bariatric Surgery" by Hilary E. Wilson-Perez # Book PDF Kindle ePub Free
eBook details
- Title: Effects and Mechanisms of Bariatric Surgery
- Author : Hilary E. Wilson-Perez
- Release Date : January 19, 2013
- Genre: Medical,Books,Professional & Technical,
- Pages : * pages
- Size : 12341 KB
Description
With obesity now reaching epidemic proportions, and the associated health risks and economic burden, effective weightloss strategies are critical. Currently, the only highly-effective, long-term treatment for obesity is weight-reduction bariatric surgery. Roux-en-Y Gastric Bypass (RYGB), the most commonly-performed bariatric surgery, decreases stomach capacity and bypasses part of the small intestine, re-routing the flow of nutrients. Vertical Sleeve Gastrectomy (VSG), a newer and lesser-known procedure, involves removal of approximately 80 percent of the stomach, and does not manipulate the intestine. VSG is rapidly gaining in popularity due to its safety and positive outcomes regarding weight loss, glycemic control, and other metabolic endpoints.Despite the broad success of bariatric surgery, we understand remarkably little about how these procedures actually produce their potent effects. One thing we know is that patients who undergo bariatric surgery frequently change their eating behavior after surgery. In particular, after RYGB, humans and rodents select or prefer foods which are lower in fat content. We investigated whether a bariatric surgical procedure limited to the stomach, VSG, causes a similar reduction of fat intake/preference. We found that VSG-operated rats decreased their intake of fat in several diet choice paradigms, and that this change in food choice is comparable to the changes induced by RYGB.One candidate to mediate the effects of VSG on food choice and other metabolic outcomes is the peptide hormone Glucagon-Like Peptide-1 (GLP-1). GLP-1 is secreted from the intestine in response to nutrient ingestion, and has potent effects to improve glycemic control and reduce food intake. Furthermore, GLP-1 secretion is greatly enhanced following VSG and RYGB, and has been widely hypothesized to be at least partially responsible for the metabolic benefits of those surgeries. To test this hypothesis, we performed VSG in mice with genetic deficiency for the GLP-1 receptor. Contrary to our hypothesis, GLP-1 receptor-deficient mice responded normally to VSG in all examined aspects, including weight loss, glycemic control, and altered food choice.These studies demonstrate for the first time the potent effect of VSG surgery to alter food choice, particularly by decreasing fat intake. These data provide another parallel between the effects of VSG and RYGB, suggesting that these two anatomically-distinct surgeries may share a common mechanism to induce their powerful effects. Regarding the nature of that mechanism, we demonstrated that GLP-1 receptor activity is not necessary for those effects to manifest in VSG-operated mice. Instead, enhanced GLP-1 secretion and changes in food choice may be downstream of more global adaptations of the digestive system in response to the surgical manipulations.
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