Boston scientists discover capsule that improves nausea or loss of appetite

A team of American scientists from Boston has discovered a way to make an ingestible capsule that boosts the production of the body's hunger-regulating hormone. This new invention could prove useful for treating diseases that involve nausea or loss of appetite.

Headed by Giovanni Traverso, an associate professor of mechanical engineering at MIT and a gastroenterologist at Brigham and Women's Hospital, the MIT engineers were interested in fixing gastrointestinal issues in human bodies.

"This study helps establish electrical stimulation by ingestible electroceuticals as a mode of triggering hormone release via the GI tract. We show one example of how we're able to engage with the stomach mucosa and release hormones, and we anticipate that this could be used in other sites in the GI tract that we haven't explored here," Traverso stated.

The stomach releases hormones, such as ghrelin, that play an important role in stimulating one's appetite. These types of hormones are produced by endocrine cells that are part of the enteric nervous system, which, in turn, controls hunger, nausea and feelings of fullness. The new artificial capsule was designed to deliver electrical currents to cells, in order to stimulate the body into producing ghrelin.

The enteric nervous system controls all aspects of digestion, including the movement of food through the gastrointestinal tract. Some patients with gastroparesis, a stomach disorder that leads to very slow movement of food, have shown symptomatic improvement after electrical stimulation generated by a device, similar to a pacemaker, that can be surgically implanted in the stomach.

The MIT team started with the hypothesis that the electrical stimulation of the stomach might be leading to the release of ghrelin. To test that hypothesis, the researchers used an electrical probe to deliver electrical stimulation to the stomachs of animals, specifically pigs. They found that after 20 minutes of stimulation, ghrelin levels in the bloodstream were significantly higher. In addition, it was found that electrical stimulation did not lead to any significant inflammation or other adverse effects.

The researchers then set out to see if they could achieve the same thing using a device that could be swallowed and temporarily reside in the stomach. The engineers produced a capsule with a grooved surface that disperses fluid away from the electrodes. This was inspired by the skin of the Australian thorny devil lizard, which uses ridged scales to collect water.

James McRae, an MIT graduate student and one of the lead authors of the study, said: "We were inspired by that to incorporate surface textures and patterns onto the outside of this capsule. That surface can manage the fluid that could potentially prevent the electrodes from touching the tissue in the stomach, so it can reliably deliver electrical stimulation."

The team tested their capsule by administering it into the stomachs of large animals, and they found that the capsule produced a substantial spike in ghrelin levels in the bloodstream. The scientists found that in order for the simulation to work, the vagus nerve, used to control digestion, must be intact. They think that the electrical pulses transmit to the brain through the vagus nerve, which then stimulates the endocrine cells and produces ghrelin.

"As far as we know, this is the first example of using electrical stimuli through an ingestible device to increase endogenous levels of hormones in the body, like ghrelin. And so, it has this effect of utilizing the body's own systems rather than introducing external agents," Khamil Ramadi said. He is the current assistant professor of bioengineering at the NYU Tandon School of Engineering and the Director of the Laboratory for Advanced Neuroengineering and Translational Medicine at NYU Abu Dhabi.

In other related news, the world's first-ever "mini-heart" was created in a petri dish by a team of German scientists. The heart is only 0.5 millimetres big and though it cannot pump blood, it functions almost as well as a real one. Another study found, through the help of Artificial Intelligence, we could slow down our ageing process.