Gut-brain mechanisms underlying the negative and positive health outcomes following bariatric surgery

Bariatric surgery is by far the most effective treatment for obesity and it involves major rerouting of the gut or transection of the stomach to reduce the amount of food that can enter. But patients also report a change in their preference for and thus desire to eat junk food. A small number also report increases in suicide, self-harm, depression and can develop alcohol and drug problems. This project aims to understand how and why these things happen.


Bariatric surgery is remarkably successful as it produces profound and sustained weight loss in combination with metabolic benefits. These benefits are thought to occur via actions on the gut-brain axis which lead to alterations in the neuroendocrine regulation of appetite and glycaemia. Furthermore, the hedonic responses to high-fat, high-sugar foods are dampened after bariatric surgery and decreased levels of compulsive forms of eating behaviour such as emotional eating and binge eating are observed. The precise mechanism responsible for these positive effects on eating behaviour is currently unknown. Evidence is also emerging which shows that subset of patients experience adverse mental health effects, including suicide, self-harm, depression and substance use disorders. The causative and contributing factors behind these adverse effects are not well understood. This project explores the utility of using a mouse model of bariatric surgery to determine the mechanisms underlying the impact of this procedure on affective behaviour including depression-like and anxiety-like behaviour, as well as operant responding for palatable food and drugs of abuse. Neurochemical analysis of brain tissue will investigate the changes in central gut hormones and their receptors potentially responsible for these changes in behaviour.

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