Stroke: Modulation of a genetic predisposition by the microbiota

An international team of researchers led by Mark Kahn of the University of Pennsylvania has recently demonstrated the link between the intestinal flora and the formation of Cerebral Cavernous Malformations responsible for strokes and seizures.

Cerebral cavernous malformations (CCMs) are vascular lesions of the central nervous system that affect about one in 200 people. Surgey is the main therapeutical approach.

The study carried out on a line of mice genetically predisposed shows that mice with many cavernomas and which microbiota have been modified do not develop lesions.

What is the explanation? The occurrence of Cerebral Cavernous Malformations (CCMs) in these animals is associated with the intra-abdominal presence of gram-negative bacteria that migrate to the brain to bind to the Toll-like receptor 4 (TLR4) responsible for Cerebral cavernous malformations. By acting on the mice intestinal flora, the Toll-like receptor 4 (TLR4) is uninhibited.

“These results in mice corroborate the observations made on humans: depending on their intestinal flora, people with the same genetic mutation may or may not develop cerebral cavernous malformations (CCMs). It is interesting to note that an unfavorable genetic predisposition could be counterbalanced by modulating the microbiota.”