Composition and metabolic activity of the intestinal microbiota in obese children and adolescents

The intestinal microbiota, according to modern data, is a “metabolic organ". Scientists distinguish a bidirectional "gut-brain" axis, the connection between the components of which is carried out thanks to intestinal microbiota and its metabolites (dopamine, short-chain fatty acids, etc.). Currently, scientific data continue to accumulate actively, studying the relationship of intestinal microbiota disorders and the development of obesity [Abenavoli, L., 2019 г. Julita Tokarek, et, 2022]. The problem of the relationship of the composition, metabolic effects of intestinal microbiota in the development of obesity has not been sufficiently studied and requires additional clarification. The study included children aged 6-18 years with obesity or overweight (74 people) (SDS BMI criterion ≥ 1) and 44 conditionally healthy children and adolescents without acute and severe chronic diseases with normal body weight (SDS BMI ≤1.0, WHO criteria). Anamnestic data were analyzed with the identification of risk factors for the development of obesity and metabolic syndrome, objective status data were evaluated, venous blood was taken (general blood analysis, biochemical blood analysis, study of the extended lipid spectrum (total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, atherogenicity index), hormones (insulin, leptin, resistin, irisin, GLP-1 and GLP-2). Instrumental research methods (ultrasound examination of abdominal organs, bioimpedance). Microbiota composition was studied by mass spectrometry (blood and feces) and 16S-RNA sequencing (feces) and microbiota metabolic activity by gas mass spectrometry (feces). The aim of the study was to establish the significance of the composition and metabolic activity of the intestinal microbiota, clinical and hormonal disorders in overweight and obese children and adolescents for early diagnosis of carbohydrate metabolism disorders. Data have been obtained that the taxonomic composition of the intestinal microbiota in obese and overweight children is characterized by the predominance of a stable phylum (type) of Actinobacteriota and a decrease in the phylum of Bacteroidota, which are part of the phylogenetic nucleus. The metabolic activity of the intestinal microbiota in obese and overweight children is characterized by a decrease in the production of all short-chain fatty acids, mainly butyrate, which is accompanied by a decrease in some types of butyrate-producing bacteria, such as Faecalibacterium. The greatest influence on metabolic activity is exerted by bacteria of the genus Bacteroides, the species Bacteroides_eggerthii. A decrease in the production of short-chain fatty acids in obese and overweight children leads to a decrease in the level of incretins, especially GLP-1 and GLP-2 in the blood, contributing to the development of carbohydrate metabolism disorders.