2024-01-26 20:35:02
MONTREAL — Chronic stress triggers a biochemical ripple effect that modifies the composition of the intestinal microbiome, shows a study carried out on mice by Chinese researchers.
This allows us to better understand how chronic stress increases the risk of various health problems, from irritable bowel syndrome to depression, the authors say.
“The most studied mechanisms are those which go from the intestine and the intestinal microbiota to the brain,” commented Professor Vincenzo Di Marzio, a specialist in the intestinal microbiome at the Faculty of Medicine of Laval University. On the other hand, the mechanisms that leave the brain and reach the intestinal microbiota are not very well known, so I believe that this is a very important study.
Chinese researchers discovered that mice that were exposed to chronic stress for two weeks subsequently had fewer cells whose role is to protect the intestines from pathogens.
Even more precisely, they found that a substance produced by intestinal bacteria that proliferate in the presence of stress interferes with the mechanism that normally allows intestinal stem cells to transform into protective cells.
The study, however, does not clarify how stress causes these bacteria to proliferate, Professor Di Marzo said.
“(Researchers) have identified a novel mechanism by which the brain, stress, changes the activity of the autonomic peripheral nervous system that affects the gut,” he explained. And in a way that is not yet well understood, it affects the composition of the intestinal microbiota by increasing species of bacteria that produce a metabolite that affects the proliferation of intestinal stem cells.
The researchers then found high levels of these bacteria and the substance in question in the stools of humans suffering from depression, compared to the stools of healthy humans.
It’s no secret that stress plays a leading role in the manifestation of several psychosomatic illnesses. Multiple studies have also demonstrated, in recent years, that the intestinal microbiota has an influence that we are only beginning to measure on multiple facets of health.
New knowledge that allows us to understand a little better the association between stress and the microbiota is therefore very useful, said Professor Di Marzo, and not only because it sheds light for the first time on the relationship between the brain and the intestine rather than the other way around.
“If there is a way for the brain to control the gut microbiota’s production of certain metabolites, the brain might also direct the microbiota to have protective functions or functions that contribute to disease, through the gut of course “, he concluded.
The findings of this study were published by the medical journal Cell Metabolism.
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