Link Found Between Stroke And Gut Microbiome

Substances produced by bacteria may be associated with the likelihood of developing vascular anomalies.

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In animal studies, scientists have already shown that substances secreted by intestinal bacteria can enter the brain with blood and cause pathologies in its vessels. Scientists have now discovered for the first time a direct link between the risk of hemorrhagic stroke and the gut microbiome in humans. The new study is published in Nature Communications.

Scientists collected stool samples from more than 100 patients with cavernous angioma. This is a vascular malformation (defect, anomaly) that occurs in about 0.5% of people. It can cause epileptic seizures and cerebral hemorrhages (hemorrhagic strokes). There is evidence that such angiomas appear in people aged 30-50 years.

It turned out that the presence of angiomas in the brain is closely related to certain indicators of the gut microbiome. Among the main characteristics, scientists named the number of Odoribacter splanchnicus above average and reduced concentrations of Faecalibacterium prausnitzii and Bifidobacterium adolescentis.

Patients with cavernous angioma, regardless of how they were taken for the study, had a similar microbiome, said Issam Awad, a professor at the University of Chicago and co-author of the study. This did not depend on whether the angiomas in the study participants were the product of hereditary mutations or were sporadic cases.

Further analysis showed that the concentration of certain substances in the body depends on the microbiome. Scientists have found increased synthesis of certain lipopolysaccharides in people whose microbiome is associated with cavernous angioma. Before that, scientists had found a similar phenomenon in mice. In animal studies, it has been shown that such molecules are carried with the bloodstream into the brain and stimulate the development of cavernous angiomas.

It is noteworthy that the analysis of bacterial populations in the intestine and the measurement of the level of certain biomarkers in the blood within the framework of this study provided great accuracy in the diagnosis of the severity of cavernous angioma.

Scientists don't expect to find a probiotic or antibiotic that can help treat this condition anytime soon. They fear that the action of such substances could spread beyond the necessary bacteria strains. Therefore, it is now impossible to fully predict the effects of such treatment.