A recent publication by Caroline Ménard shows that chronic stress, as occurs in cases of bullying, can make the blood-brain barrier more permeable to contaminants and microbes that may be in the blood. As the brains of depressed individuals show signs of inflammation, Caroline Ménard and her colleagues had hypothesized that leakiness of the blood brain barrier could allow molecules and microbes to reach the brain, causing inflammation.
"Our study is the first to demonstrate that peripheral inflammation induced by chronic social stress can directly affect the brain by altering the integrity of the blood-brain barrier. It also confirms the central role of inflammation in the development of depressive symptoms "
said Dr. Ménard.
This advance could have clinical repercussions on three levels, says the researcher. First, it suggests that we could diagnose major depression in people at risk, those who suffer from cardiovascular diseases for example, by evaluating the permeability of the BBB by magnetic resonance. Second, since blood molecules can cross this barrier, it is possible that brain molecules can pass into the bloodstream. Some of these molecules could therefore be used as blood biomarkers for depression. Finally, in the longer term, we could consider the development of new treatments for depression that would target the expression of claudin-5 in order to maintain the integrity of the blood-brain barrier," concludes Caroline Ménard.
Learn more about this important discovery here:
- New & Views in Nature Neuroscience: An opening for humor in melancholy (subcription required)
- Le chaînon manquant entre stress social et dépression | L'inflammation causée par un stress social chronique peut entrouvrir la porte qui protège le cerveau, par Jean Hamann, Journal Le Fil de l'Université Laval (French)
- Le lien stress-dépression élucidé - Jean-François Cliche, Le Soleil (French)
- Le lien entre intimidation et dépression se précise - La Presse (French)
Original Research Article (subcription required):
Social stress induces neurovascular pathology promoting depression, Menard, Caroline, Pfau Madeline L., Hodes Georgia E., Kana Veronika, Wang Victoria X., Bouchard Sylvain, Takahashi Aki, Flanigan Meghan E., Aleyasin Hossein, LeClair Katherine B., Janssen William G., Labonte Benoit, Parise Eric M., Lorsch Zachary S., Golden Sam A., Heshmati Mitra, Tamminga Carol, Turecki Gustavo, Campbell Matthew, Fayad Zahi A., Tang Cheuk Ying, Merad Miriam, and Russo Scott J. , Nature Neuroscience, 2017/12/01, Volume 20, Issue 12, p.1752 - 1760, (2017) Google Scholar RIS