Self-Powered Implant Short-Circuits Hunger Pangs

A new study describes how a battery-free implanted device gently stimulates vagal afferent fibers to reduce food intake and achieve weight control.

Developed by researchers at the University of Wisconsin (WISC; Madison, USA) and the University of Electronic Science and Technology of China (Chengdu, China), the vagus nerve stimulation system is comprised of a flexible, biocompatible, battery-free nanogenerator that is attached to the surface of stomach, generating biphasic electric pulses in response to gastric peristalsis. The electric signals generated by the device stimulate vagus nerve afferent fibers in order to reduce food intake and realize weight control.

In a rat model, the researchers achieved a 38% weight loss in just 15 days, which was maintained for a period of 100 days without rebound. When the researchers removed the devices after a period of 12 weeks, the rats resumed their normal eating patterns and their excess weight returned. A potential advantage of the new device over existing vagus nerve stimulators, according to the researchers, is that it is a smart, self-responsive system that does not require external charging. The study was published on December 17, 2018, in Nature Communications.

“The pulses correlate with the stomach's motions, enhancing a natural response to help control food intake. It's automatically responsive to our body function, producing stimulation when needed. Our body knows best,” said senior author professor of materials science and engineering Xudong Wang, PhD, of WISC. “Our expectation is that the device will be more effective and convenient to use than other technologies.”

It has been known for a century that the vagus (tenth cranial) nerve, a mixed parasympathetic nerve containing both afferent and efferent nerve fibers, acts as a signal bridge to transport information between the central nervous system and the body. Neuromodulation, as a non-destructive, reversible therapeutic strategy, can manipulate body functions by stimulating or influencing neurophysiological signals through the neural networks to achieve therapeutic purpose.

Related Links:
University of Wisconsin
University of Electronic Science and Technology of China