Pathogenetic Substantiation of the Therapeutic Impact on Microbiota in Irritable Bowel Syndrome

Abstract

Aim. This review aims to describe the nature of changes in the intestinal microbiota in irritable bowel syndrome (IBS) and provide a pathogenetic justification of the feasibility of a therapeutic impact on microbiota. General findings. An important aspect of the interaction of intestinal bacteria with the “host” cells is their contact with pattern recognition receptors of enterocytes, dendritic cell receptors, as well as a transcellular transport of antigens in the region of Peyer’s patches. The area of interaction of intestinal bacteria and the human body is not limited to the intestines. Intestinal bacteria demonstrate a significant humoral effect due to signalling molecules, some of which exhibit neurotransmitter properties. The study of the bacterial cross-feeding for various species, i.e. mutual use of nutrient substrates produced by bacteria of various species, is of a great interest. The development of a low-activity inflammation in IBS can partly be explained by the increased interaction of flagellin with the corresponding receptor, as well as the influx of excess bacteria from the small intestine. The majority of studies on IBS have demonstrated the predominance of intestinal bacteria with pro-inflammatory potential (Enterobacteriaceae) and the lack of bacteria with a pronounced anti-inflammatory, antimicrobial and enzymatic action (Lactobacillus and Bifidobacterium), as well as increased mucus degradation. Similar changes are observed in inflammatory bowel diseases. Reduced microbial diversity increases susceptibility to intestinal infections and parasitoses, including those caused by protozoa conditionally pathogenic for adults, such as Blastocystis hominis hominis, Dientamoeba fragilis, Giardia lamblia. With the help of nutrition correction, the use of probiotics and functional foods containing certain probiotic strains, plant fibres (primarily psyllium) and, in some cases, nonabsorbable antibiotics, a positive effect can be achieved in a significant number of IBS patients. Recent works have shown that clinical improvement is accompanied by a change in the composition of the intestinal microbiota. Conclusion. For the pathogenetic treatment of irritable bowel syndrome, the use of non-drug treatment is justified, such as diet optimization and prescription of plant fibres and probiotic bacterial strains. The positive effect of such an approach is largely determined by modification of the intestinal microbiota composition. This opens up prospects for a further, more targeted impact on the intestinal microbiome.