Is the intestinal microbiota involved in some strokes?
Cerebral cavernous malformations, or cavernomas, are malformations of blood vessels in the brain. Abnormally dilated, they form ball-shaped conglomerations. Some forms, called familial, are made more likely by recently identified genetic mutations. Generally asymptomatic, cavernomas can sometimes cause neurological problems (headaches, vision problems, epilepsy, etc.). Although the risk is minimal, the primary concern is the potential for cerebral hemorrhage.
Researchers whose work was recently published in Nature showed that the cell receptor in the body whose role is to recognize various germs is involved in the development of cavernomas. When the receptor is activated by the presence of certain bacteria, the formation of cavernomas is accelerated, but when the receptor is blocked, it prevents their formation. Lastly, the study authors demonstrated that germ-free mice (with no microbiota) and mice that had undergone an antibiotic treatment to eliminate their microbiota are protected against the disease. These discoveries shed light on the direct role of the intestinal microbiota and constitute a potential therapeutic target to treat this vascular anomaly.
Alan T. Tang et al. Endothelial TLR4 and the microbiome drive cerebral cavernous malformations. Nature 545, 305–310 (18 May 2017) doi:10.1038/nature22075