New research suggests that a hormone treatment could help people reap some of the benefits of gastric bypass without having the surgery.
The infusions lasted for 12 hours per day and contained three gut hormones, the levels of which increase in people who undergo gastric bypass surgery.
The hormone combination has the name GOP, which is short for glucagon-like peptide 1, oxyntomodulin, and peptide YY.
The 15 trial participants who received the GOP hormone infusions lost an average of 4.4 kilograms (kg) compared with 2.5 kg of weight loss in 11 control participants whose infusions contained a saline solution.
The results also showed that those who received the gut hormone treatment experienced near normal glucose levels without large swings in glucose and insulin. Those who received the saline did not show this improvement.
In a Diabetes Care paper about the study, the authors conclude that "GOP infusion at home was feasible and well tolerated over a 4-week period."
However, they also observe that, while GOP infusion resulted in "a substantial mean weight loss of 4.4 kg," the difference between this amount and the average weight loss in the control group was not statistically significant, "likely due to small sample sizes."
The participants gave themselves the infusions at home. The researchers instructed them to connect the portable infusion pump 1 hour before breakfast and to disconnect it around 12 hours later, after their last meal each day.
Both groups received advice about diet, healthful eating, and weight loss and stopped their usual diabetes treatment during the study period.
More treatments for obesity needed
Obesity used to be a public health concern that only affected high-income nations. However, according to the World Health Organization (WHO), rates of obesity and excess weight are also increasing in middle- and low-income countries.
In the United States, estimates for 2015–2016 from the Centers for Disease Prevention and Control (CDC) suggest that obesity affects 39.8% of adults, or about 93.3 million people.
Gastric bypass surgery is a type of weight loss surgery that can help people with obesity to shed excess weight and help those who also have type 2 diabetes to improve their blood sugar levels.
However, not all patients who qualify for the surgery want it. In addition, the procedure can result in complications, such as stomach pain, persistent vomiting and nausea, and blood sugar levels that are too low.
"There is a real need," says senior study author Tricia M. Tan, a professor in the Department of Metabolism, Digestion, and Reproduction at Imperial College London, in the United Kingdom, "to find new medicines, so we can improve and save the lives of many patients."
Previous research had suggested that a rise in GOP hormones could be a factor in the success of gastric bypass surgery.
It appears that after gastric bypass surgery, the small intestine and colon produce more GOP hormones. A rise in GOP hormones can spur weight loss, suppress the appetite, and improve the ability of cells to take in and use sugar from digested food.
Benefit of gut hormones to treat obesity
The purpose of the new study was to investigate the extent to which increasing GOP hormone levels without undergoing gastric bypass surgery might produce the same benefits.
Prof. Tan concludes that "Although this is a small study, our new combination hormone treatment is promising and has shown significant improvements in patients' health in only 4 weeks."
In addition to running the trial — in which they had randomly assigned the participants to the GOP hormone and saline groups — the researchers also monitored glucose levels and weight loss in two other groups.
The two other groups included, respectively, 21 people who underwent gastric bypass surgery and 22 who followed a very low calorie diet.
The people who followed the very low calorie diet or who underwent the surgery lost a lot more weight than those who received GOP treatment. The average weight loss was 10.3 kg in the surgery group and 8.3 kg in the diet group.
However, compared with gastric bypass surgery, GOP infusion seemed to have a more beneficial effect on blood glucose.
While participants who had undergone surgery achieved overall improvements in blood sugar, their glucose levels had bigger highs and lows.
In contrast, those who received the GOP infusion experienced "near normal" blood sugar with steadier, less variable levels.
Prof. Tan says that, while it may result in less weight loss, GOP infusion appears to carry fewer side effects, compared with surgery.
The team is planning a larger clinical trial with more participants and a longer treatment period.
"This study adds to emerging evidence of the potential benefit of future medications that are a combination of gut hormones for the treatment of obesity," comments Professor Lora Heisler, Chair in Human Nutrition at the Rowett Institute of the University of Aberdeen, in the U.K. She was not involved in the study.
"Compared to other methods, the treatment is noninvasive and reduced glucose levels to near normal levels in our patients."
Prof. Tricia M. Tan