The relationship between intestinal dysbiosis and acute cerebrovascular accident

Introduction. Acute cerebrovascular accident remains one of the most common causes of disability and mortality not only in Russia, but throughout the world. About 12 million cases of ischemic stroke are registered annually, and more than 30 % of patients remain dependent on outside help even after rehabilitation. Despite significant advances in the study of pathogenesis, traditional risk factors such as hypertension, atherosclerosis, and diabetes mellitus do not explain all cases of the disease. Recently, the role of the intestinal microbiota in the origin of cerebrovascular diseases, including ischemic stroke, has been actively investigated. The intestinal-brain axis is considered as a key pathway of interaction between the microbiota and the central nervous system. The human microbiome has ceased to be considered solely as a symbiotic system involved in digestion. Numerous studies demonstrate its key role in regulating immunity, metabolism, neuronal activity, and even behavior through the gut–brain axis. In the context of ischemic stroke, the microbiota can influence the pathogenesis of the disease through several mechanisms, which makes its study critically important for the development of new therapeutic strategies. The intestinal microbiome, numbering trillions of microorganisms, is involved in the regulation of the immune response, metabolism, the blood-brain barrier and systemic inflammation, which can affect the development, severity and outcome of stroke. However, the mechanisms of this effect remain poorly understood, and the clinical data are contradictory.

The aim of the study: to study the role of the composition and species activity of the intestinal microbiota in the risk of developing and determining the degree of ischemic stroke, with the identification of potential microbial markers.

Materials and methods. The study involved 64 people with a median age of 62 years. 4 groups were formed according to the clinical course of stroke: healthy people without signs of stroke (n=19), mild cerebrovascular accident (n=15), moderate cerebrovascular accident (n=15), severe cerebrovascular accident (n=15). In all groups, anamnesis was collected and stool analysis was performed using 16S-ribosomal RNA genetic sequencing to determine the species composition of the intestinal microbiota.

Results. The analysis of the intestinal microbiota in patients with acute cerebrovascular accident of varying severity and healthy individuals revealed significant differences in the composition of key bacterial species. A typical composition of the microbiota of the large intestine of different types of cerebrovascular accident was also compiled. Based on the values of the regression coefficients, the factors: the proportion of microorganisms such as Proteobacteria and Actinobacteriota, have a direct relationship with the likelihood of cerebrovascular accident. Thus, an increase in the proportion of Proteobacteria by 1 % increases the chances of cerebrovascular accident by 10,5 times (95 % CI 2,08–53,33), an increase in the proportion of Actinobacteriota by 1 % increases the chances of cerebrovascular accident by 5,3 times (95 % CI 2,12–13,35).

Conclusion. The gut microbiota is a potentially modifiable risk factor for stroke that affects it through multiple mechanisms. Further research should be aimed at establishing causal relationships, identifying key microbial markers, and developing methods for correcting dysbiosis for stroke prevention and treatment.

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