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Hormone injection aids weight loss without need for gastric bypass operation

Published: 07 August 2019

New research supported by the NIHR has shown that an injection of gut hormones helps obese people lose weight via a similar mechanism to gastric bypass surgery.

The study found patients lost on average 4.4kg and the treatment led to substantial improvements to their blood glucose, with some patients' reducing to near-normal levels. 

The weight loss achieved was smaller than in those having a gastric bypass operation. However, the hormone treatment has the benefit of being non-invasive and having fewer side effects than surgery. 

The research was supported by the NIHR Imperial Biomedical Research Centre and trialled on patients at the NIHR Imperial Clinical Research Facility

Previous research by Imperial College London suggested that one of the reasons why gastric bypass surgery works so well is because three specific hormones originating from the bowels are released in higher levels. This hormone combination, called 'GOP' for short, reduces appetite, causes weight loss and improves the body's ability to use the sugar absorbed from eating.

Researchers wanted to see if infusing patients with the GOP hormones to mimic the high levels seen after surgery could aid weight loss and reduce high glucose levels.

Twenty-six obese patients with prediabetes (when blood glucose is too high but not high enough to be classified as diabetes) and those with diabetes were recruited to the study at Hammersmith Hospital from July 2016 to October 2018. Fifteen patients were randomly selected to receive the hormone treatment and 11 patients were given a saline (salt water) infusion as a placebo over a four-week period. The team also recruited 21 patients who had undergone bariatric surgery and 22 patients who followed a very low-calorie diet to compare the results of GOP. 

In the trial, patients on the GOP treatment lost an average of 4.4kg, compared with 2.5kg for participants receiving a saline placebo. The treatment also had no side effects.

However, patients who received bariatric surgery or who followed a very low calorie diet lost significantly more weight than GOP patients. The changes in weight were 10.3kg for bariatric patient and 8.3kg for patients who followed a very low calorie diet. 

The team also found GOP was capable of lowering blood glucose levels to near-normal levels, with little variation in the blood glucose. Patients who received bariatric surgery also had an overall improvement in blood glucose, but the levels were much more variable, leaving them vulnerable to low blood glucose levels.

Professor Tricia Tan, Professor of Practice at Imperial College London and lead author of the study, said: "Although the weight loss was smaller, using the GOP infusion would be preferable as it has fewer side effects than bariatric surgery. This result shows that it is possible to obtain some of the benefits of a gastric bypass operation without undergoing the surgery itself. If further trials are successful, in future we could potentially give this type of treatment to many more patients."


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