Mechanisms in bariatric surgery: Gut hormones, diabetes resolution, and weight loss

Obesity has received much attention worldwide in association with an increased risk of cardiovascular diseases, diabetes, and cancer. At present, bariatric surgery is the only effective treatment for obesity in which long-term weight loss is achieved in patients. By contrast, pharmacological interventions for obesity are usually followed by weight regain. Although the exact mechanisms of long-term weight loss following bariatric surgery are yet to be fully elucidated, several gut hormones have been implicated. Gut hormones play a critical role in relaying signals of nutritional and energy status from the gut to the central nervous system, in order to regulate food intake. Cholecystokinin, peptide YY, pancreatic polypeptide, glucagon-like peptide-1, and oxyntomodulin act through distinct yet synergistic mechanisms to suppress appetite, whereas ghrelin stimulates food intake. Here, we discuss the role of gut hormones in the regulation of food intake and body weight.

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Food preferences and underlying mechanisms after bariatric surgery

Proceedings of The Nutrition Society ◽

10.1017/s0029665115002074 ◽

2015 ◽

Vol 74 (4) ◽

pp. 419-425 ◽

Cited By ~ 36

Author(s):

Preeshila Behary ◽

Alexander D. Miras

Keyword(s):

Bariatric Surgery ◽

Weight Loss ◽

Gastric Bypass ◽

Eating Behaviour ◽

Food Preferences ◽

Gut Hormones ◽

High Energy ◽

Sweet Taste ◽

Current Evidence ◽

Fatty Food

Bariatric surgery leads to significant long-term weight loss, particularly Roux-en-Y gastric bypass (RYGB). The mechanisms underlying weight loss have not been fully uncovered. The aim of this review is to explore the changes in food preferences, as a novel mechanism contributing to weight loss, and also focus on the underlying processes modulating eating behaviour after bariatric surgery. Patients after gastric bypass are less hungry and prefer healthier food options. They develop an increased acuity to sweet taste, which is perceived as more intense. The appeal of sweet fatty food decreases, with functional MRI studies showing a corresponding reduction in activation of the brain reward centres to high-energy food cues. Patients experiencing post-ingestive symptoms with sweet and fatty food develop conditioned aversive behaviours towards the triggers. Gut hormones are elevated in RYGB and have the potential to influence the taste system and food hedonics. Current evidence supports a beneficial switch in food preferences after RYGB. Changes within the sensory and reward domain of taste and the development of post-ingestive symptoms appear to be implicated. Gut hormones may be the mediators of these alterations and therefore exploiting this property might prove beneficial for designing future obesity treatment.

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Recombinant Human Leptin Does Not Alter Gut Hormone Levels after Gastric Bypass but May Attenuate Sweet Cravings

International Journal of Endocrinology ◽

10.1155/2014/120286 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Rushika Conroy ◽

Gerardo Febres ◽

Donald J. McMahon ◽

Michael O. Thorner ◽

Bruce D. Gaylinn ◽

...

Keyword(s):

Bariatric Surgery ◽

Weight Loss ◽

Gastric Bypass ◽

Gut Hormones ◽

Liquid Meal ◽

Gut Hormone ◽

Sweet Cravings ◽

The Impact ◽

To Receive ◽

Reduced State

Bariatric surgery improves glucose homeostasis and alters gut hormones partly independent of weight loss. Leptin plays a role in these processes; levels are decreased following bariatric surgery, creating a relative leptin insufficiency. We previously showed that leptin administration in a weight-reduced state after Roux-en-Y gastric bypass (RYGB) caused no further weight loss. Here, we discuss the impact of leptin administration on gut hormones, glucostasis, and appetite. Weight stable women after RYGB were randomized to receive placebo or recombinant human metreleptin (0.05 mg/kg twice daily). At weeks 0 and 16, a liquid meal challenge was performed. Glucose, insulin, C-peptide, GLP-1, PYY, glucagon, and ghrelin (total, acyl, and desacyl) were measured fasting and postprandially. Appetite was assessed using a visual analog scale. Mean post-op period was53±2.3months; mean BMI was34.6±0.2 kg/m2. At 16 weeks, there was no significant change in weight within or between groups. Fasting PYY was significantly different between groups and the leptin group had lower sweets craving at week 16 than the placebo group (P<0.05). No other differences were observed. Leptin replacement does not alter gut hormones or glucostasis but may diminish sweet cravings compared to placebo in this population of post-RYGB women.

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The Role of Gut Hormones in Diet-Induced Weight Change: A Systematic Review

Hormone and Metabolic Research ◽

10.1055/s-0043-115646 ◽

2017 ◽

Vol 49 (11) ◽

pp. 816-825 ◽

Cited By ~ 9

Author(s):

Xue Zhao ◽

Qing Han ◽

Xiaokun Gang ◽

You Lv ◽

Yujia Liu ◽

...

Keyword(s):

Bariatric Surgery ◽

Weight Loss ◽

Large Scale ◽

Weight Regain ◽

Dietary Intervention ◽

Gut Hormones ◽

Current Evidence ◽

Cochrane Library ◽

Weight Changes ◽

Gut Hormone

AbstractGut hormones are known to play an important role in long-term weight loss maintenance after bariatric surgery. However, the interplay between gut hormones and diet-induced weight changes remains unclear. Our aims were to evaluate the alterations of gut hormones in diet-induced weight loss, weight maintenance, and weight regain periods. Available studies were searched on MEDLINE, EMASE, ClinicalTrials.gov, the Cochrane Library, and Web of science from inception to October 2016. After selection, 16 studies with 656 participants were included. Based on current evidence, we found significant alterations of gut hormones induced by different diets. In weight-loss diets, decreased fasting total PYY, GLP-1, CCK, GIP, PP, and amylin along with increased ghrelin levels were observed in most studies. After weight loss, the persistent decreases of fasting total PYY and GLP-1 levels as well as increased appetite were reported, suggesting the profound impact of altered gut hormones on later weight regain after dietary intervention. The differences between diet-induced changes in gut hormones and other treatments such as bariatric surgery and exercise are also discussed in this review. Although significant alterations of gut hormones were found during weight changes, huge heterogeneity exists in methods and populations. More large-scale studies with elaborate design addressing the gut hormone alterations in dietary weight regulation are required in the future.

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Do Gut Hormones Contribute to Weight Loss and Glycaemic Outcomes after Bariatric Surgery?

Nutrients ◽

10.3390/nu13030762 ◽

2021 ◽

Vol 13 (3) ◽

pp. 762

Author(s):

Dimitris Papamargaritis ◽

Carel W. le Roux

Keyword(s):

Bariatric Surgery ◽

Weight Loss ◽

Glucose Homeostasis ◽

Hormone Secretion ◽

Eating Behaviour ◽

Early Period ◽

Specific Inhibitor ◽

Gut Hormones ◽

Current Evidence ◽

Gut Hormone

Bariatric surgery is an effective intervention for management of obesity through treating dysregulated appetite and achieving long-term weight loss maintenance. Moreover, significant changes in glucose homeostasis are observed after bariatric surgery including, in some cases, type 2 diabetes remission from the early postoperative period and postprandial hypoglycaemia. Levels of a number of gut hormones are dramatically increased from the early period after Roux-en-Y gastric bypass and sleeve gastrectomy—the two most commonly performed bariatric procedures—and they have been suggested as important mediators of the observed changes in eating behaviour and glucose homeostasis postoperatively. In this review, we summarise the current evidence from human studies on the alterations of gut hormones after bariatric surgery and their impact on clinical outcomes postoperatively. Studies which assess the role of gut hormones after bariatric surgery on food intake, hunger, satiety and glucose homeostasis through octreotide use (a non-specific inhibitor of gut hormone secretion) as well as with exendin 9–39 (a specific glucagon-like peptide-1 receptor antagonist) are reviewed. The potential use of gut hormones as biomarkers of successful outcomes of bariatric surgery is also evaluated.

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