Tiny implantable device short-circuits hunger pangs, aids weight loss

20 Dec 2018 --- A new battery-free, easily implantable weight-loss device developed by engineers at the University of Wisconsin-Madison could offer a promising future route for aiding weight-loss. Published in Nature Communications, laboratory testing results demonstrated that the devices helped rats shed almost 40 percent of their body weight. The devices could be used as reversible alternatives to the permanent gastric bypass procedure, for example, the researchers note.

Measuring less than 1 centimeter across, the tiny devices – which are implantable via a minimally invasive procedure – generate gentle electric pulses from the stomach's natural churning motions and deliver them to the vagus nerve, which links the brain and the stomach. That mild stimulation “dupes” the brain into thinking that the stomach is full after a small amount of food.

“The pulses correlate with the stomach's motions, enhancing a natural response to help control food intake,” says Xudong Wang, a UW-Madison Professor of Materials Science and Engineering.

There is an existing unit on the market that also stimulates the vagus nerve for weight-loss. However, Wang explains how this device has several advantages over the existing unit. “Maestro,” approved by the Food and Drug Administration (FDA) in 2015, administers high-frequency zaps to the vagus nerve to shut down all communication between the brain and stomach. However, it requires a technical control unit and “bulky” batteries which frequently must be recharged, Wang notes.

That ongoing maintenance can be a big barrier to use, comments Luke Funk, Surgery Professor in UW-Madison's Division of Minimally Invasive, Foregut and Bariatric Surgery. 

“One potential advantage of the new device over existing vagus nerve stimulators is that it does not require external battery charging, which is a significant advantage when you consider the inconvenience that patients experience when having to charge a battery multiple times a week for an hour or so,” Funk notes.

Wang’s device contains no batteries, no electronics and no complicated wiring, instead relying on the undulations of the stomach walls to power its internal generators. This means the device only stimulates the vagus nerve when the stomach moves.

“It's automatically responsive to our body function, producing stimulation when needed,” says Wang. 

“Our expectation is that the device will be more effective and convenient to use than other technologies,” he adds.

Although this technology is currently in the early stages of development, it does point to future fruitful collaborations between health and technology in tackling global issues such as obesity.

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