Introducing the brain: the effects of stress (Introduction)

by David Turell , Wednesday, February 07, 2024, 18:29 (79 days ago) @ David Turell

Major effects through the immune system:

https://medicalxpress.com/news/2024-02-stress-brain-psyche-immune.html

"Chronic stress has far-reaching consequences for our bodies. For example, many stress-related psychiatric illnesses, such as depression, are associated with changes in the immune system. However, the underlying mechanisms of how these changes affect the brain remain largely unknown.

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"'We were able to show that stress increases the amount of the matrix metalloproteinase-8 (MMP-8), an enzyme in the blood of mice. The same changes were found in patients with depression," says author Flurin Cathomas. MMP-8 travels from the blood to the brain, where it alters the functioning of certain neurons. In the affected mice, this leads to behavioral changes: they withdraw and avoid social contact.

"According to Cathomas, the findings are novel in two respects: "Firstly, they indicate a new 'body-mind mechanism,' which might be relevant not only for stress-related mental illness but also for other diseases that affect both the immune and nervous systems." Secondly, says the psychiatrist, identification of the specific MMP-8 protein could be a potential starting point to develop new treatments for depression.
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"The researchers were able to use animal models to show that stress increases the migration of a specific type of white blood cells called monocytes into the vascular system of the brain, particularly into the reward center regions. These monocytes produce MMP-8. MMP-8 is involved in the restructuring and regulation of the net-like frame that surrounds neurons in the brain—called the extracellular matrix.

"'If MMP-8 penetrates the brain tissue from the blood, it changes the matrix structure and thus disrupts the functioning of the neurons. Mice who are affected by this process display changes in behavior that are similar to those seen in humans with depression," says Cathomas.

"In order to prove that MMP-8 was really responsible for the behavioral changes, the researchers removed the MMP-8 gene from some of the mice. Compared to the control mice, these animals did not display stress-related negative behavioral changes.

"'Blood analyses of patients with depression indicate that the findings from the mouse models are also relevant for humans: both the monocytes and MMP-8 were increased in the blood of people with depression in comparison to healthy participants.'"

Comment: we come back to the same issue: depression is immaterial but is produced by a sick brain which is material. In dualism theory the separate consciousness sends a proper message which is then interpreted in a distorted fashion by the sick brain.