Introducing the brain: how the brain monitors immune system (Introduction)

by David Turell , Wednesday, May 01, 2024, 20:42 (16 days ago) @ David Turell

New discoveries:

https://www.sciencedaily.com/releases/2024/05/240501125818.htm

"The brain can direct the immune system to an unexpected degree, capable of detecting, ramping up and tamping down inflammation, shows a new study in mice from researchers at Columbia's Zuckerman Institute.

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"The scientists looked for connections the brain might have with inflammation and innate immunity, the defense system shared by all animals and the most ancient component of the immune system. Whereas the adaptive immune system remembers previous encounters with intruders to help it resist them if they invade again, the innate immune system attacks anything with common traits of germs. The relative simplicity of innate immunity lets it respond to new insults more quickly than adaptive immunity.

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"The Zuker lab turned to a bacterial compound that sets off innate immune responses. The scientists found that giving this molecule to mice activated the caudal nucleus of the solitary tract, or cNST, which is tucked inside the brainstem. The cNST plays a major role in the body-brain axis and is the primary target of the vagus nerve.

"The scientists showed that chemically suppressing the cNST resulted in an out-of-control inflammatory response to the immune insult: levels of pro-inflammatory molecules released by the immune system were more than three times higher than usual, and levels of anti-inflammatory immune compounds were roughly three times lower than normal. In contrast, artificially activating the cNST reduced pro-inflammatory molecule levels by nearly 70 percent and increased anti-inflammatory chemical levels almost tenfold.

"'Similar to a thermostat, this newfound brain circuit helps increase or decrease inflammatory responses to keep the body responding in a healthy manner," said Dr. Jin, who started this study as a postdoctoral researcher in Dr. Zuker's lab. Dr. Jin is now a tenure track investigator at the National Institute of Allergy and Infectious Diseases. "In retrospect, it makes sense to have a master arbiter controlling this vital response."

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"'A lot of psychosomatic effects could actually be linked to brain circuits telling your body something," Dr. Jin noted.

"The scientists identified the specific groups of neurons in the vagus nerve and in the cNST that help detect and control pro- and anti-inflammatory activity. "This opens up a new window into how the brain monitors and modulates body physiology," said Dr. Zuker, a professor of biochemistry, molecular biophysics and neuroscience at Columbia's Vagelos College of Physicians and Surgeons.

"Discovering ways to control this newfound brain circuit may lead to novel therapies for common auto-immune diseases such as rheumatoid arthritis, type I diabetes, multiple sclerosis, neurodegenerative diseases, lupus, inflammatory bowel disease and Crohn's disease, as well as conditions such as long COVID syndrome, immune rejection of transplanted organs, and the potentially deadly outbursts known as cytokine storms that COVID infections can trigger.

"Autoimmune diseases may affect roughly one in 10 individuals, a 2023 Lancet study suggested. In the United States alone, autoimmune diseases may cost the economy $100 billion annually, a figure that may be a gross underestimate, according to the Autoimmune Association."

Comment: the Vigus nerve wanders all over the body influencing every organ. It is one of twelve cranial nerves that connect directly to the brain. All but the Vagus are specific. The Vagus is a generalist and probably the most important.