Obesity is a common and serious disease in the United States, affecting two out of five people. When someone is obese (a body mass index of 30 or more), your weight is unhealthy, which increases your risk of type 2 diabetes, heart disease, stroke, and certain types of cancer.
Current weight loss options include diet and exercise, which in some cases are unsuccessful, FDA-approved appetite suppressant medications with known side effects, and invasive procedures such as bariatric surgery, which requires long-term lifestyle changes.
A team of scientists from the Massachusetts Institute of Technology (MIT), Brigham and Women’s Hospital, and Harvard University have developed a non-invasive alternative: an oral capsule that contains a small vibrating motor designed to stimulate the stomach to produce the same feeling of satiety that people experience after eating a large meal.
In a preclinical animal study published in Scientific advancesThe researchers found that when pigs were given the vibrating electronic capsule before meals, they significantly reduced their food consumption and gained weight more slowly compared to when they did not receive the treatment.
“The metabolic responses triggered by the ingestible capsule have the potential to benefit people struggling with obesity. By simulating fullness, this capsule could facilitate weight loss and better glycemic control,” said Dave Rampulla, Ph.D., director of NIBIB’s Science and Technology Discovery Division.
An artificial feeling of satiety
Previous investigations has shown that applying external vibrations to a muscle tendon can create an illusory sensation of movement. The researchers wanted to see if applying vibrations to the stomach could cause an artificial feeling of satiety.
“We wanted to explore whether we could use the body’s own sensory feedback mechanisms to create a feeling of fullness in the stomach. Our proof-of-concept study examined whether vibrations would induce and stimulate stretch receptors in the stomach, allowing the stomach to distend and send signals to the brain that create an illusory feeling of fullness,” said senior author Shriya Srinivasan, Ph.D., assistant professor of bioengineering at Harvard University.
To test the concept, the research team designed a capsule containing a small battery-operated device with a vibrating motor and a gelatinous membrane that will dissolve in the human stomach when mixed with gastric juices. The vibrations activate the stretch receptors in the stomach in the same way as when we eat. This sends a signal to the brain to initiate hormones that help us digest food, feel full, and stop eating.
Evaluation in a large animal model.
The researchers evaluated their vibrating capsule in a porcine model because their gastric anatomy is similar to that of humans and biomedical gastrointestinal devices have previously been evaluated in pigs.
To evaluate how the capsules affected appetite and the amount of food consumed, the researchers designed an experiment with four pigs. The scientists compared how much each pig ate over two weeks with the vibrating capsule and how much each pig ate over two weeks without the vibrating capsule. During treatment, the vibrating capsule was activated before each meal for 30 minutes. The results showed that, on average, the four pigs ate 40% less feed when treated with the capsule. Intake of a given meal was the proportion of food consumed in the first 30 minutes.
The researchers evaluated whether the vibrating capsules affected weight gain. They found that the treated pigs gained weight more slowly than the untreated ones. Their body weight was measured at least twice a week during the study, although the researchers did not quantify the results.
The researchers also evaluated the effects of vibrating capsules in fasted pigs on hormones involved in digestion, satiety, and appetite. Six pigs were treated with the capsules and six different pigs received a “dummy” pill (placebo). Blood samples revealed that treated animals experienced a marked reduction in the hunger hormone ghrelin compared to untreated animals. This decrease represents a reduction in appetite, which facilitates weight loss.
The safety of the vibrating capsules was also evaluated in the treated pigs and no adverse effects were reported. Further experiments showed that it took four to five days for the capsules to pass through the animals’ digestive tract.
The main limitations of the study were related to the use of a young pig model for laboratory research. The researchers said it was challenging to quantify their weight loss and plan to study the vibrating pill next in other animals with a stomach geometry similar to that of humans.
“Following further safety validations, clinical translation could facilitate a paradigm shift in potential therapeutic options for obesity and other diseases affected by delayed stomach fullness, which leads to excessive overeating and subsequent metabolic, cardiac, and endocrine conditions,” said the study’s senior author, Giovanni Traverso, M.D., Ph.D., an associate professor of mechanical engineering at MIT and a gastroenterologist at Brigham Women’s Hospital.
This research was supported in part by a NIBIB grant (R01EB000244).
This prominent scientist describes a basic research finding. Basic research increases our understanding of human behavior and biology, which is critical to promoting new and better ways to prevent, diagnose, and treat diseases. Science is an unpredictable and incremental process: each research advance builds on past discoveries, often in unexpected ways. Most clinical advances would not be possible without knowledge of fundamental basic research.
Study reference: Shriya S. Srinivasan et al. An ingestible, vibrating bioelectronic stimulator modulates gastric stretch receptors to achieve illusory satiety. Scientific Advances: 2023. 9, eadj30039. DOI: 10.1126/sciadv.adj3003
The graph seen above was taken from the post on Scientific advances and is licensed under the Creative Commons Attribution 4.0 International License.
