TAXONOMIC CHARACTERISTICS OF THE COLON MICROBIOTA AND ITS RELATIONSHIP WITH THE ENDOCRINE SYSTEM IN CHILDREN AND ADOLESCENTS WITH OVERWEIGHT AND OBESITY
Authors:   Siberian State Medical University (SSMU), Tomsk, Russia, Samoilova Yu.G. , Sagan E.V. ,   Siberian State Medical University (SSMU), Tomsk, Russia, Oleinik O.A. ,   Siberian State Medical University (SSMU), Tomsk, Russia,   "Nebbiolo" Center for Clinical Trials, LLC, Tomsk, Russia, Kudlay D.A. ,   National Research Center Institute of Immunology of the Russian Federal Biomedical Agency, Moscow, Russia,   I.M. Sechenov First Moscow State Medical University, Moscow, Russia, Matveeva M.V. ,   Siberian State Medical University (SSMU), Tomsk, Russia, Tolmachev I.V. ,   Siberian State Medical University (SSMU), Tomsk, Russia, Podchinenova D.V. ,   Siberian State Medical University (SSMU), Tomsk, Russia, Kovarenko M.A. ,   Siberian State Medical University (SSMU), Tomsk, Russia
Published: October 2022

Composition of the intestinal microbiota and its influence on human metabolism, including hormone synthesis, has been studied in many research works, but the data obtained as yet does not allow forming the general idea of microbiota composition in overweight and obese individuals. The purpose of the research was to determine the internal microbiota composition and its relationship with certain hormones in children against the background of weight gain. A single-stage single-center comparative study was carried out in parallel groups in Dec. 2018 - May 2021, which included 74 children, of which 38 (51.3%) boys and 36 (48.6%) girls, median age 12.1 [10.8; 14.6] years old, with overweight and constitutional-exogenous obesity (CEO) of different grades compared to 44 healthy children (26 (59.09%) boys and 18 (40.9%) girls, median age 13.1 [10.5; 13.8] years old). The anthropometric assessment included: measuring height with 1-millimeter accuracy; body weight with 100-gram accuracy (without shoes and outerwear on the scales). The calculation of BMI SDS and height SDS was carried out using the software developed by the WHO, “AnthroPlus,” for children aged 6 to 19 years old with the BMI SDS formula used as follows: (x-X)/SD, where x is the patient's BMI, X is the average BMI for a given age and gender, SD is the standard deviation of the BMI index for a given age and gender. The investigation of the intestinal microbiota using the DNA metagenomic sequencing of stool samples (sequencing the V4 region of 16S ribosomal RNA (rRNA) gene) was carried out using the QIAamp® PowerFecal® DNA Kit by QIAGEN in accordance with the manufacturer's instructions at the laboratory facilities of the “Knomics” microbiome research company (Skolkovo, Moscow, Russia). The levels of leptin, insulin, irisin, resistin, GLP-1 and GLP-2 were evaluated in blood serum by ELISA using the laboratory kits from the CLOUD-CLONE CORP. (CCC, USA) using the enzyme immunoassay reactions analyzer UNIPLAN (Russia). The information about the following taxonomic composition of the intestinal microbiota was obtained during the research: the level of Firmicutes demonstrated the absence of a statistically significant difference in the groups (p=0.645); the level of Actinobacteriota and Euryarchaeota was statistically significantly higher in group 1 (in overweight and obese children and adolescents) than in group 2 (p=0.002 and p=0.002, respectively); the level of Bacteroidota was statistically significantly lower in group 1 than in group 2 (p< 0.001); statistically significantly lower level of certain hormones in group 1 compared to group 2 (glucagon (p=0.001), resistin (p=0.019), GLP-1 (p<0.001), and GLP-2 (p< 0.001)); statistically significantly higher concentration of insulin (p=0.001) and leptin (p=0.008). Statistically significantly higher levels of the following bacterial genus were revealed in microbiota in children from group 1 compared to the control group 2: Bifidobacterium (p=0.007); Agathobacter (p=0.002); Dorea (p=0.001); Blautia (p=0.016); Lachnoclostridium (p=0.012); Roseburia (p=0.012); Collinsella (p<0.001); and Holdemanella (p=0.034), while statistically significantly lower levels of: Faecalibacterium (p<0.001); Subdoligranulum (p<0.001); Bacteroides_vulgatus (p=0.042); Bacteroides (p=0.001); Bacteroidesmassiliensis (p=0.002); Bacteroides_eggerthii, Alistipes (p<0.001); and Parabacteroides_merdae (p=0.002). The data on the average multidirectional and insignificant correlations of microbiota composition and hormone levels in obese children compared to the children and adolescents from healthy group have been obtained as well, which requires further studying. The decrease in the strength of the relationship between specific representatives of the intestinal microbiota and the level of certain hormones in overweight and obese children obtained in this research is probably associated with an imbalance in the “microbiota-metabolism” axis.