When the brain helps regulate inflammation
For a long time, the immune system was primarily viewed as an independent defense system. However, it is becoming increasingly clear that immune responses, the nervous system, and the brain communicate closely with each other.
A study published in Nature in 2024 by Hao Jin and his team provides fascinating experimental insights into this.
The vagus nerve transmits information about inflammation.
In a mouse model, the researchers were able to demonstrate that specific pro-inflammatory and anti-inflammatory messenger substances are detected by different groups of vagal nerve cells. This information is then transmitted via the vagus nerve to specific nerve cells in the brainstem. The brain thus receives feedback on what is currently happening within the immune system.
But communication doesn't only happen from the body to the brain.
The brain, in turn, influences the immune response.
Things became particularly interesting when the researchers deliberately altered this control loop.
When certain nerve cells in the brainstem were switched off, the inflammatory response became significantly more unbalanced.
However, when certain components of the control loop were experimentally activated, pro-inflammatory messenger substances decreased and anti-inflammatory signals increased.
The authors therefore describe the nerve cells involved as a kind of biological regulator that helps to balance the immune response.
So it's not simply a matter of "more or less inflammation".
This is an important point. A functioning immune response must be able to react to a threat. At the same time, the organism must prevent this reaction from continuing uncontrollably. Therefore, what is crucial is not simply minimizing inflammation, but rather ensuring appropriate regulation.
What does this mean for our understanding of chronic diseases?
The study reveals something fundamental:
The nervous system and the immune system are not separate worlds.
The organism regulates inflammatory responses via a network involving immune messengers, peripheral nerves, and the brain.
For us, this systemic perspective is particularly interesting.
Not only the question "What has changed in the immune system?" is relevant, but also:
How does the entire organism perceive these signals, how does it process them – and how does it regulate its reaction?
This changes the way we view health and regulation.
The body is not made up of separate systems that function independently of each other. The brain, autonomic nervous system, immune system, metabolism, and organs are in constant communication with one another.
This also fits with the concept of Cell Danger Response (CDR) according to Prof. Robert Naviaux: It describes how cells, when faced with threat or stress, not only change individual processes, but also coordinate their metabolism, communication and behavior.
And that is precisely why it is worthwhile to consider health as a regulatory process of the entire organism.
Source: Jin H, Li M, Jeong E, Castro-Martinez F, Zuker CS. A body–brain circuit that regulates body inflammatory responses. Nature. 2024;630:695-702.DOI: 10.1038/s41586-024-07469-y
