Researchers are reporting that the presence of abnormal bundles of brittle blood vessels in the brain or spinal cord, called cavernous angiomas (CA), are linked to the composition of a person’s gut bacteria. Also known as cerebral cavernous malformations, these lesions which contain slow moving or stagnant blood, can often cause hemorrhagic strokes, seizures, or headaches.
For the study, the researchers used advanced genomic analysis techniques to compare stool samples from 122 people who had at least one CA as seen on brain scans, with those from age- and sex-matched, control non-CA participants. Initially, they found that on average the CA patients had more gram-negative bacteria whereas the controls had more gram-positive bacteria, and that the relative abundance of three gut bacterial species distinguished CA patients from controls. Moreover, gut bacteria from the CA patients appeared to produce more lipopolysaccharide molecules which have been shown to drive CA formation in mice. According to the authors, these results provided the first demonstration in humans of a "permissive microbiome" associated with the formation of neurovascular lesions in the brain.
The study, funded by the NINDS with some support from the NHLBI, appeared in Nature Communications.