The Vagus Nerve, Inflammation, and Pain

According to new work from The Feinstein Institute for Medical Research in Manhasset, New York, it is possible to “use” the vagus nerve to help treat rheumatoid arthritis (RA) and other conditions.

“We know from previous studies that the vagus nerve is a conduit for signals from many of our vital organs and that it has a role in reporting changes in inflammation to the brain, ” said Patricio T. Huerta, Ph.D., Feinstein Institute investigator and corresponding author of the paper. “Our new finding clearly shows that the vagus nerve carries immune-related signals, which makes it a good target for bioelectronic treatment for autoimmune conditions such as rheumatoid arthritis, Crohn’s disease and lupus.”

“In this study, we were looking to sharpen our understanding of what makes the vagus nerve sense the immune response, ” said Dr. Huerta. “We devised an electrode setup to record down to the vagus fibers that are activated by the cytokines. We found that similar to how the brain perceives and interprets colors differently, each cytokine is perceived and interpreted by the vagus nerve differently.”

Dr. Huerta commented to OTW, “Previous work done here at The Feinstein Institute has shown that stimulating the vagus nerve can have a strong effect in the immune system. This means that the brain can send signals that travel though the vagus nerve and influence immune cells, leading them to inhibit the production of cytokines, and reduce inflammation in the body.”

“Our work asked the reverse question: Can the cytokines produced by immune cells exert an effect in the vagus nerve? If this were the case, then the brain would be informed about the state of the immune system. Indeed, successfully tapping into the immune-related signals travelling through the vagus could provide us with a full understanding of how different immune-related receptors within the vagus trigger different reactions in the brain. This information can be used to identify the different mechanisms to treat a condition using bioelectronic medicine.”

“One of the biggest achievements in this study was the method we developed to record the signals traveling throughout the vagus nerve. We developed our own electrode-recording device and also a method to cut through the tough outer layer of the nerve to have better access to its axons. This method is easily repeatable and can be used for future studies to map the different signals of the vagus nerve as well as other nerves within the body.”

“It was this electrode setup which let us discover that the immune system does have an impact on and can trigger a response by the nervous system. Our in vivo recordings have shown that different cytokines are sensed by the vagus nerve, which was not previously known.”

“Pain management is an important issue after orthopedic surgery. We think that controlling and manipulating the signal flow through the vagus nerve into the brain has tremendous potential to become an alternative approach to reduce the pain linked to inflammation.”