Researchers have shed light on the existence of a “stress axis” in our body that extends from our brain to our adrenal glands, and contributes to the development of anxiety, depression, metabolic diseases and diabetes .
- There is a “stress axis” in our body, starting from the hypothalamus in the brain and reaching the adrenal glands which produce cortisol
- By passing from one organ to another, stress modifies the genes, which can have the long-term consequence of the appearance of psychic disorders such as depression, but also of metabolic diseases.
According to a survey conducted in January 2016 by BVA for the Chambre Syndicale de la Sophrologie, 19% of French people say they are “stressed most of the time” and 42% “from time to time”.
Chronic stress that has direct consequences on our mental and physical health since in the long term, it can lead to metabolic diseases, accelerate aging and cause psychic disorders such as anxiety and depression.
In a study published in the journal Science Advances, researchers from the Weizmann Institute of Science in Israel and the Max Planck Institute of Psychiatry in Germany have shed light on the role played in our organism by the “stress axis” which starts from the hypothalamus in our brain to get to the adrenal glands, which produce the hormone cortisol. When the stress axis is continually activated, changes occur in cells and organs, and the continued production of cortisol then contributes substantially to the symptoms of chronic stress.
Genes modified by stress
To study the long-term consequences of chronic stress on the body, the researchers mapped the entire length of the stress axis. The experiment, conducted on two series of mice – one unstressed and the other exposed to chronic stress – revealed the activity of 21,723 cells located along this axis.
Comparing the results obtained on the two groups of mice, they noted that when the stress message passed from one organ to another, the expression of genes in the cells and the tissues themselves underwent significant changes. . In total, the researchers found 66 altered genes between normal mice and stressed mice in the hypothalamus, 692 in the pituitary and 922 in the adrenal glands. It is in these adrenal glands that they noted the most significant alterations among the various cells.
In these adrenal glands, the researchers were able to identify for the first time a subpopulation of cells that plays a crucial role in the response and adaptation to stress. Located in the adrenal cortex, they carry the Abcb1b gene, which is overexpressed when these cells are under stress. According to the researchers, it is possible that the Abcb1b gene plays a role in the release of cortisol.
Abcb1 gene variants cause stress-related illnesses
It now remains to be determined whether the results obtained on mice are relevant to humans. To find out, the researchers analyzed adrenal glands that had been removed from patients to relieve symptoms of Cushing’s disease. It turned out that the cells of the adrenal glands of these patients presented a picture similar to that of the mice belonging to the chronic stress group and also expressed the Abcb1 gene.
However, the Abcb1 gene is known thanks to previous studies on the genetics of depression. By performing blood tests on subjects suffering from depression and under temporary stress, the researchers found that certain gene variants affect how the adrenal glands process stress signals which then move down the stress axis.
This can lead to affect the whole body and be the cause of diseases such as diabetes or metabolic diseases. Researchers now want their work to open up “new directions for future research” and that they may result in the treatment of illnesses due to chronic stress.
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