Manipulating the vagus nerve
Using the bioelectronic approach, researchers have been able to stimulate the vagus nerve and to turn off the release of TNF. Researchers believe that the indirect route works by activating the vagus nerve communications to the spleen nerves which increases the production and release of neurotransmitters. This increased release of neurotransmitters has a direct effect on the immune cells called T-cells and increases the release of certain substances, which causes a reduction in the release of TNF from the macrophages.
Kox notes that it may be possible that macrophages are more directly affected by the neurotransmitters from the vagus nerve itself and further notes that this pathway is extremely complex and requires further research.
Research has already been done on rodents showing that there seems to be a link between TNF levels and activation of the vagus nerve, but research on this interaction inside of humans is limited. Tracey still states that the problem with autoimmune diseases may lie in a problem with the vagus nerve.
Research has already revealed that the vagus nerve plays a major role in controlling heart rate and patients who have rheumatoid arthritis typically have a higher heart rate than individuals who are healthy. Whereas everyone once thought that the impairments in the vagus nerves were caused by the diseases, some are now speculating whether or not the diseases could be stemming from the impairments.