[Correction of gut dysbiosis as a promising direction in the prevention of neuroinflammation and cognitive impairment].

In recent years new data have been obtained on the role of intestinal dysbiosis in the pathogenesis mechanisms of neuroinflammation and neurodegeneration in Alzheimer's disease (AD), as well as on the influence of dietary patterns (Mediterranean diet, MIND diet) and probiotics on the correction of dysbiosis and slowing down the development of cognitive disorders. It seems reasonable to draw the attention of practicing physicians to the need to prevent cognitive dysfunction through dietary correction, probiotics and prebiotics intake. The purpose of the research was to study the possibility of using certain dietary patterns, as well as intake of probiotics and prebiotics for the correction of dysbiosis and early prevention of cognitive dysfunction, basing on the analysis of published data on the bidirectional communication between the colon microbiota and the brain and microbiota changes in patients with cognitive dysfunction and AD. Material and methods . We searched domestic and foreign literature devoted to gut microbiota, the "gut-brain" axis, microbiota disorders in AD patients; mechanisms of neuroinflammation and neurodegeneration; the role of dietary patterns, in particular MIND diet, pre- and probiotics in the prevention of cognitive dysfunction - via PubMed search engine, SemanticScholar Google Internet search platform and domestic scientific electronic library Cyberleninka. 72 literature sources were analyzed. Results . Intestinal dysbiosis and disruption of intestinal barrier integrity play an important role in the pathogenesis of neuroinflammation and neurodegeneration. Changes in the microbiota in patients with cognitive impairment and AD are associated with disease severity and are generally characterized by increased numbers of Gram-negative microorganisms in Bacteroidetes and Proteobacteria phyla and decreased numbers of Gram-positive microorganisms in Firmicutes and Actinobacteria phyla. An increase in gram-negative microorganisms abundance leads to elevated release of lipopolysaccharides (LPS) that disrupt the integrity of the intestinal mucous barrier and, through a series of steps, initiate neuroinflammation. Course application of probiotics containing representatives of Bifidobacterium and Lactobacillus genera, in particular, Bifidobacterium breve A1 и Lactobacillus plantarum С29 strains, leads to improved cognitive function, which can be explained by anti-inflammatory and antioxidant effects. Long-term prospective studies of the effects of dietary patterns such as the Mediterranean diet and the MIND diet clearly show delayed regression of cognitive function in older adults without initial dementia as well as in patients with AD. For example, according to various studies, individuals who have strictly adhered to the Mediterranean diet for 6-9 years have a 23-39% lower risk of developing cognitive impairment. Adherence to the MIND diet for 6 years has a statistically significant association with higher verbal memory scores. Correction of gut dysbiosis, including through the administration of probiotics, prebiotics and bringing the diet to the MIND diet pattern, is the most affordable and rational method for early prevention of cognitive dysfunction. Conclusion . A promising strategy in the early prevention of neuroinflammation, cognitive impairment and dementia is to maintain the balance of the gut microbiota. The solution to this problem is achieved by adjusting the dietary pattern, increasing the use of dietary fiber and prebiotics and reasonable use of probiotics.