A mechanical appetite suppressant: Researchers have developed an electronic capsule that, after ingestion, triggers a feeling of satiety through vibrations in the stomach. In tests on pigs, the capsules were able to reduce food intake by 40 percent, were well tolerated and were excreted without any problems. The concept could represent a minimally invasive treatment alternative to medication or surgical interventions, especially for severely overweight people. Thanks to the relatively uncomplicated technology, the capsules would also be suitable for inexpensive mass production, say the developers.
Many weigh a little too much - but for some people this takes on pathological forms: it is estimated that around 650 million people worldwide are affected by obesity. This is associated with a significantly increased risk of a number of health problems such as cardiovascular disease, diabetes and certain forms of cancer. Obesity can have various causes, but it is often caused by permanently excessive food intake. Behavioral therapies to change eating habits are often unsuccessful - many of those affected find it difficult to resist the strong urge to eat. In such cases, appetite-suppressing medications are used or even so-called surgical procedures are carried out in which the stomach capacity is restricted. However, both approaches are associated with side effects and are too expensive for many of those affected.
Can the natural system be activated?
Against this background, researchers led by Shriya Srinivasan from the Massachusetts Institute of Technology (MIT) in Cambridge have now developed a concept that is based on a regulatory factor for the natural feeling of satiety. Specialized cells sense the stretching of the stomach during a meal. At a certain level, these mechanoreceptors then send the signal to the brain via the vagus nerve that it is now enough. Signal substances and hormones are then released that aid digestion and trigger a feeling of satiety. At the same time, the level of an appetite-stimulating hormone is also reduced.
Srinivasan and her colleagues came up with the idea for the vibration capsule because of previous research that found vibrations can make muscles feel as if they have stretched further than they actually have. “I therefore wondered whether we could also activate the stretch receptors in the stomach using vibration to trick them into thinking that there is a strong stretch,” says Srinivasan.
To trigger this effect, the researchers use a technology that is currently being developed for other applications at MIT: swallowable capsules that can fulfill certain functions in the body using electronic units. For the current application target, the team has now developed a capsule the size of a multivitamin preparation that contains a vibrating element that is powered by a small silver oxide battery. When the capsule reaches the stomach, stomach fluids dissolve a membrane, completing an electronic circuit that activates the vibration motor. In the previous test version it runs for 30 minutes.
A minimally invasive treatment alternative
The scientists examined the extent to which an appetite-suppressing effect can actually be achieved in pigs. Initially, blood tests showed that as soon as the capsules began to vibrate in the empty stomachs of the test animals, the researchers noticed hormone release patterns that are typically observed after a meal. The researchers then tested the effects of this effect on the appetite of the test animals. This showed that if the pill was activated for around 20 minutes before food was offered, the animals ate an average of 40 percent less than if the capsule was inactive in their stomach. The study also found that the pigs showed no signs of constipation or other negative effects from the capsules: These passed through the digestive tract without any problems and were then excreted.
“There is an intense effect on eating behavior through the use of the natural satiety system instead of an exogenous therapeutic agent or intervention,” summarizes senior author Giovanni Traverso from MIT. The system could therefore develop into a sensible alternative to current treatment approaches for stubborn obesity. “For many populations, some of the treatments for obesity are very expensive. On the other hand, on a large scale, our device could be manufactured at a fairly cost-effective price,” says Srinivasan. “Specifically, people who want to lose weight or control their appetite could take such a capsule before every meal,” says the scientist.
Until then, however, further development work is necessary: Above all, the tolerability and effectiveness of the concept must now be tested in humans, the researchers conclude.
Source: Massachusetts Institute of Technology, specialist article: Science Advances doi: 10.1126/sciadv.adj3003