Psychology

Stimulation

Gastric emptying

Neuromodulation

Vagus nerve

Neuroscience

Bioinformatics

Biology

Gastroparesis

Internal medicine

Stomach

Vagus nerve stimulation

Medicine

Nature Reviews Gastroenterology & Hepatology

The gastrointestinal tract has extensive, surgically accessible nerve connections with the central nervous system. This provides the opportunity to exploit rapidly advancing methods of nerve stimulation to treat gastrointestinal disorders. Bioelectric neuromodulation technology has considerably advanced in the past decade, but sacral nerve stimulation for faecal incontinence currently remains the only neuromodulation protocol in general use for a gastrointestinal disorder. Treatment of other conditions, such as IBD, obesity, nausea and gastroparesis, has had variable success. That nerves modulate inflammation in the intestine is well established, but the anti-inflammatory effects of vagal nerve stimulation have only recently been discovered, and positive effects of this approach were seen in only some patients with Crohn’s disease in a single trial. Pulses of high-frequency current applied to the vagus nerve have been used to block signalling from the stomach to the brain to reduce appetite with variable outcomes. Bioelectric neuromodulation has also been investigated for postoperative ileus, gastroparesis symptoms and constipation in animal models and some clinical trials. The clinical success of this bioelectric neuromodulation therapy might be enhanced through better knowledge of the targeted nerve pathways and their physiological and pathophysiological roles, optimizing stimulation protocols and determining which patients benefit most from this therapy. Electric stimulation of nerves might be useful for various gastrointestinal disorders. In this Review, the authors discuss neuromodulation therapies in relation to current knowledge of the nerve circuitry, provide insights into possible mechanisms and explore reasons for limited success and how effectiveness might be improved.

Bioelectric neuromodulation for gastrointestinal disorders: effectiveness and mechanisms