by University of Manitoba

Non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) improves the colitis-related disease activity index (DAI) and macroscopic score. Credit: Bioelectronic Medicine (2024). DOI: 10.1186/s42234-024-00162-5

A simple, non-invasive treatment focused on the ears could one day provide relief for people with ulcerative colitis, a UM research study has found.

The study, “Exploring the efficacy of transcutaneous auricular vagus nerve stimulation (taVNS) in modulating local and systemic inflammation in experimental models of colitis,” has just been published in the journal Bioelectronic Medicine.

Ulcerative colitis, a type of inflammatory bowel disease, is a chronic immune condition that causes inflammation and ulcers inside the colon. Symptoms can include diarrhea, abdominal cramping, fatigue and weight loss. People with ulcerative colitis can develop life-threatening complications.

To perform the study, scientists from the immunology department in the Max Rady College of Medicine chemically induced a condition that mimics acute ulcerative colitis in mice. As a treatment, they applied gentle electrical pulses to the outer ears of the mice in order to stimulate the vagus nerve.

The researchers used the treatment, called transcutaneous auricular vagus nerve stimulation, to stimulate specific areas of both ears in mice for 10 minutes per day for six days.

“This stimulation activates the brain–gut axis through the vagus nerve, which can control gut inflammation,” said Fatemeh Hesampour, a Ph.D. candidate who led the study as her doctoral research project.

“In both mice and humans, the part of the outer ear where the vagus nerve is most accessible is the cymba conchae, the ‘pocket’ above the ear hole.”

Mice that received the stimulation showed significant symptom improvement. Compared with untreated mice, they experienced less weight loss, reduced intestinal damage and lower inflammatory marker levels. The treatment also increased levels of anti-inflammatory molecules, suggesting that it helps to restore balance in the immune system.

“In the near future, this treatment could offer a safe, drug-free option for patients with ulcerative colitis who have not found success with other treatments, or this treatment could be added to a patient’s therapies,” said Dr. Jean-Eric Ghia, professor of immunology, who supervised the study.

The researchers were surprised to find that stimulating the vagus nerve via the ears had positive effects even in healthy mice, potentially opening doors for preventive care and improving gut health.

A recent proof-of-concept clinical trial of non-invasive vagus nerve stimulation of the ears in children with inflammatory bowel disease was conducted in the U.S., showing beneficial results. More clinical trials in humans are needed, Ghia said.

The research team is now investigating how the treatment affects specific immune cells in different parts of both diseased and healthy colons in mice.

“This research offers hope for a future where managing ulcerative colitis could be as simple as a daily ear-stimulation session using the same type of earbud that is used for listening to music,” Ghia said.

More information: Fatemeh Hesampour et al, Exploring the efficacy of Transcutaneous Auricular Vagus nerve stimulation (taVNS) in modulating local and systemic inflammation in experimental models of colitis, Bioelectronic Medicine (2024). DOI: 10.1186/s42234-024-00162-5

Provided by University of Manitoba

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