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Bariatric surgery addressing large problems

Sixty-one per cent of Australians are overweight or obese, and despite countless fad diets and apparent quick-fix solutions, this figure is on the rise. Bariatric surgery is the only available clinical treatment for obesity. Professor Brian Oldfield wants to understand why lap band surgery -- the simplest form of bariatric surgery -- has such a strong influence on our stomach-to-brain interactions.



The two most common types of bariatric surgery are the adjustable gastric band, or lap band, and Roux-en-Y gastric bypass. In Australia, more than 80 per cent of procedures involve the adjustable gastric band, which doctors inflate according to the patient's needs. Brian believes bariatric surgery is a viable option for obese people if dieting and other lifestyle changes have failed.

"If you look at the figures on the impact of different interventions or strategies, people can lose five per cent of their body weight by changing their diet and exercise regime, sometimes more," says Brian. "But if you look at those people over eight or 10 years, virtually all of them return to their original weight. That's because we have a genetic environment in our bodies that drives us to maintain body fat."

"Whatever breed of bariatric surgery you want to talk about, patients lose at least 25 to 30 per cent of their body weight and 60 to 70 per cent of their excess body weight."

Brian says the adjustable gastric band has advantages over the more complex Roux-en-Y procedure that dominates bariatric surgery in the United States. He says the importance lies not in the band itself, but in the chemical reactions it creates.

"Initially, everybody thought people ate less with a gastric band fitted because it was restrictive. It just stopped the food getting in so you couldn't eat as much. It doesn't work like that. We are charged with finding out the mechanism of the effectiveness of the adjustable gastric band."

Brian believes a better understanding of why the band works could eliminate the need for surgery altogether.

"Knowing why the band works is important because it can change the way you do bariatric surgery," he says. "It can give you confidence and you can market it better. But the real impact is if you understand the stomach-to-brain interactions that can cause satiety or eliminate diabetes, we can actually bypass bariatric surgery. That's the major long-term driver."

Brian is also working on a project involving lipolysis, the process whereby the nervous system breaks down body fat. By tracking a mutated form of Pseudorabies virus through the nervous system, Brian is hoping to increase lipolysis preferentially. He says this could lead to a reduction in abdominal fat which, unlike subcutaneous fat, relates to issues like cardiovascular disease and diabetes.

"We thought there may be some differential input from the nervous system to subcutaneous fat and abdominal fat, and that in some way the brain controls these differently," he says. "Given that the activity of brain pathways is mediated by neurotransmitters, it could be possible to modulate the activity of the pathways that were going to abdominal fat."

"The advantage we have is a Pseudorabies virus that glows red and a Pseudorabies virus that glows green. You can inject the green virus into the subcutaneous fat and the red virus into abdominal fat, follow their passage through the nervous system and map the pathways that are controlling subcutaneous or abdominal fat. So you can start to investigate the changes in genes in specific nerve cells that are related to one type of fat or the other."

Keywords

  • Obesity & Diabetes
  • energy expenditure
  • Bariatric Surgery
  • neuroscience
  • brown adipose tissue

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Projects 2005 2022

Research Output 1977 2018

AgRP Neurons Require Carnitine Acetyltransferase to Regulate Metabolic Flexibility and Peripheral Nutrient Partitioning

Reichenbach, A., Stark, R., Mequinion, M., Denis, R. R. G., Goularte, J. F., Clarke, R. E., Lockie, S. H., Lemus, M. B., Kowalski, G. M., Bruce, C. R., Huang, C., Schittenhelm, R. B., Mynatt, R. L., Oldfield, B. J., Watt, M. J., Luquet, S. & Andrews, Z. B., 13 Feb 2018, In : Cell Reports. 22, 7, p. 1745-1759 15 p.

Research output: Contribution to journalArticleResearchpeer-review

Open Access
File

Evaluating anhedonia in the activity-based anorexia (ABA) rat model

Milton, L. K., Oldfield, B. J. & Foldi, C. J., 1 Oct 2018, In : Physiology and Behavior. 194, p. 324-332 9 p.

Research output: Contribution to journalArticleResearchpeer-review

A focus on reward in anorexia nervosa through the lens of the activity-based anorexia rodent model

Foldi, C. J., Milton, L. & Oldfield, B. J., 1 Oct 2017, In : Journal of Neuroendocrinology. 29, 10, 9 p., e12479.

Research output: Contribution to journalReview ArticleResearchpeer-review

Open Access
File

Characterization of the central neural projections to brown, white, and beige adipose tissue

Wiedmann, N. M., Stefanidis, A. & Oldfield, B. J., 1 Nov 2017, In : FASEB Journal. 31, 11, p. 4879-4890 12 p.

Research output: Contribution to journalArticleResearchpeer-review

Improving efficacy of the adjustable gastric band: Studies of the use of adjuvant approaches in a rodent model

Stefanidis, A., Lee, C. C. M., Brown, W. A. & Oldfield, B. J., Feb 2017, In : Surgery for Obesity and Related Diseases. 13, 2, p. 291-304 14 p.

Research output: Contribution to journalArticleResearchpeer-review

Press / Media

Ask the Doctor - Series 1 Episode 1 Obesity

Michael John Farrell & Brian John Oldfield

16/05/17

1 media contribution

Press/Media: Profile/Interview