By studying the brains of people with depression at the time of their death, the team led by Caroline Ménard, professor at the Faculty of Medicine at Laval University and researcher at the CERVO Research Center, noticed that the alterations in the brain caused by depression were located in different regions depending on gender.
Attributable to a loss of the claudin-5 protein, these alterations are manifested by a reduction in the tightness of the blood-brain barrier, which separates the brain and the peripheral blood circulation.
In a previous study, Professor Ménard’s team had shown that, in male mice as in men, the alterations are localized in the nucleus accumbens, a region of the brain involved in the control of emotions and in reward.
By repeating the experiment on female mice, the scientists observed that chronic stress alters their brain barrier differently.
When we expose our female mice to stress, the region of the brain where the barrier is more fragile is different than in male mice., explains Caroline Ménard in an interview on the show It’s even better in the afternoon.
Instead of being located in the nucleus accumbens, the alterations in the blood-brain barrier caused by the decrease in the protein claudin-5 were instead located in the prefrontal cortex, an area of the brain that plays a role in mood regulation. , anxiety and self-perception.
The researchers made the same findings by analyzing the brains of women who suffered from depression when they died.
Caroline Ménard reminds that twice as many women as men suffer from depression. In addition, they have different symptoms and do not react to antidepressants in the same way.
Professor Ménard believes that the study carried out by her team, the results of which were published Monday in the journal Nature Communications, could lead to an improvement of current treatments.
Since there is still a good proportion of people who are resistant to these treatments, perhaps treating the barrier also as a complement, it could improve the treatments we currently have, reduce inflammation. Protecting that barrier, that could be a promising avenue, advises Caroline Ménard.
His team also discovered a blood marker linked to the health of the brain barrier. It is soluble E-selectin, an inflammatory molecule found in blood samples from women with depression, but not from men.
Go beyond questionnaires
According to Caroline Ménard, soluble E-selectin could be used for the screening and diagnosis of depression as well as to measure the effectiveness of the treatments used to treat it.
You should know that in 2022, depression is still only diagnosed with questionnaires, then it is believed that having a biomarker that would help for the diagnosis, but also for the monitoring of treatments, would facilitate the development of more personalized treatments., argues the researcher.
However, she specifies that before getting there, it will first be necessary to conduct clinical studies on larger cohorts in order to confirm the reliability of the results obtained so far.