Stimulating the Vagus Nerve Reduces Chronic Inflammation for Children With IBD
A proof-of-concept study has shown how non-invasive stimulation of the vagus nerve can reduce inflammatory symptoms of IBD.
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Non-invasive stimulation of the vagus nerve through the ear reduces inflammation for pediatric patients with inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, reports a new study. The results of the proof-of-concept clinical trial were published in Bioelectronic Medicine.
Crohn's disease and ulcerative colitis are characterized by chronic inflammation in the gastrointestinal tract and affect an estimated 3 million US adults. Nearly a quarter of patients with IBD experience symptoms – including abdominal pain, fatigue and weight loss – before 20 years of age, and prevalence of IBD in children is rising.
“Currently approved biological medications for children with IBD have the potential for side effects and may not help fully alleviate symptoms or lead to disease healing,” said Dr. Benjamin Sahn, lead author of the study and co-director of the pediatric inflammatory bowel disease center at Cohen Children’s Medical Center.
Why target the vagus nerve?
The vagus nerve plays a multitude of roles within the body – as the main nerve of the parasympathetic nervous system, it controls involuntary functions such as heart rate, digestion and the immune response, while also connecting the brain to all major organs.
The inflammatory reflex, also controlled by the vagus nerve, activates innate immune responses and inflammation in the presence of pathogens or tissue damage. When this response goes into overdrive, it can lead to chronic inflammatory conditions including rheumatoid arthritis, lupus and IBD.
By stimulating the vagus nerve with electricity, control over the inflammatory reflex can be restored, reducing the release of pro-inflammatory proteins and overall inflammation.
In the trial, Sahn and colleagues examined the impact of non-invasive, non-pharmacological transcutaneous auricular vagus nerve stimulation (ta-VNS) over a short-term period (2 weeks) and a long-term period (12 weeks).
The ta-VNS was delivered from a commercially available transcutaneous electrical nerve stimulator (TENS) unit. They placed a sensor probe with two earbuds in the left ear, where the vagus nerve is most accessible. Previous research has shown that stimulating the vagus nerve in this way activates the same regions as implanted devices that deliver direct brain stimulation.
The trial’s 22 participants were between 10 and 21 years of age, had mild to moderate ulcerative colitis or Crohn’s disease and displayed elevated levels of fecal calprotectin (an inflammatory marker) at the start of the study.
Reducing both Crohn’s disease and ulcerative colitis symptoms
The trial was composed of two phases. In the first phase, half of the participants received ta-VNS once daily for two weeks then switched to sham stimulation for two weeks, while the remaining half received the opposite. In the second phase, all participants received ta-VNS twice daily for 12 weeks.
After the first two weeks of ta-VNS, four participants saw a decrease in their IBD symptoms. Of those who received the sham stimulation first, three participants saw an increase in their symptoms, followed by a decrease when they started the ta-VNS.
However, three participants saw an improvement in their symptoms while receiving the sham treatment within the first phase of the trial. Two of these participants received the sham stimulation before ta-VNS.
At the end of the trial, half of the participants with Crohn’s disease and a third of the participants with ulcerative colitis were in remission. Interestingly, the researchers noted that patients with ulcerative colitis saw improvements earlier in the trial than those with Crohn’s disease.
Furthermore, for the majority of the cohort (64.7%), levels of the inflammatory marker measured at the beginning of the trial had reduced by at least 50%.
“These proof-of-concept study results show that non-invasive vagus nerve stimulation should be studied further and considered an alternative or additive to pharmacologic therapy”, said Sahn.
Reference: Sahn B, Pascuma K, Kohn N, Tracey KJ, Markowitz JF. Transcutaneous auricular vagus nerve stimulation attenuates inflammatory bowel disease in children: a proof-of-concept clinical trial. Bioelect Med. 2023;9(1):23. doi: 10.1186/s42234-023-00124-3
This article is a rework of a press release issued by the Feinstein Institutes for Medical Research. Material has been edited for length and content.