FEATURES OF THE BLOOD MICROBIOME IN OBESE CHILDREN
Authors:   Pirogov Russian National Research Medical University, Moscow, Russia, Kirilina I.V. ,   "Center for Molecular Health," LLC, Moscow, Russia, Shestopalov A.V. ,   Pirogov Russian National Research Medical University, Moscow, Russia,   "Center for Molecular Health," LLC, Moscow, Russia, Gaponov A.M. ,   "Center for Molecular Health," LLC, Moscow, Russia, Kamaldinova D.R. ,   Research Laboratory for Omix Technologies with the Institute of Fundamental Medicine and Biology of the Kazan and the Volga Region Federal University (KFU), Kazan, Republic of Tatarstan, Russia, Khusnutdinova D.R. ,   Research Laboratory for Omix Technologies with the Institute of Fundamental Medicine and Biology of the Kazan and the Volga Region Federal University (KFU), Kazan, Republic of Tatarstan, Russia, Grigorieva T.V. ,   Research Laboratory for Omix Technologies with the Institute of Fundamental Medicine and Biology of the Kazan and the Volga Region Federal University (KFU), Kazan, Republic of Tatarstan, Russia, Teplyakova E.D. ,   Rostov State Medical University, Rostov-on-Don, Russias, Yudin S.M. ,   Center for Strategic Planning and Management of Medical and Biological Health Risks of the Russian Federal Biomedical Agency, Moscow, Russia, Makarov V.V. ,   Center for Strategic Planning and Management of Medical and Biological Health Risks of the Russian Federal Biomedical Agency, Moscow, Russia, Rumyantsev A.G. ,   Pirogov Russian National Research Medical University, Moscow, Russia, Borisenko O.V. ,   Pirogov Russian National Research Medical University, Moscow, Russia, Rumyantsev S.A. ,   Pirogov Russian National Research Medical University, Moscow, Russia,   "Center for Molecular Health," LLC, Moscow, Russia
Published: October 2022

Lifestyle and nutrition of a modern human being is steadily leading to an increasing prevalence of obesity among adults and children. The development and progression of obesity is directly related to changes in the intestinal microbiota, which is also the main source of blood bacterial DNA. The purpose of the research was to study the taxonomic representation of bacterial DNA in the blood of healthy children vs. children with obesity. Materials and methods used: a single-center one-stage study was carried out. 170 children, of which 78 (45.88%) girls and 92 (54.12%) boys, aged 10 to 18 years old were examined in 2019 - 2020. The following clinical groups were formed: the observation group of children with Classes I to III obesity (81 in total); and the comparison group of children without obesity/metabolic disorders who applied to the same clinic with a checkup purpose (89 in total): age p=0.3162, gender p=0.0269. The assessment of taxonomic representation of bacterial DNA in the blood was performed using metagenomic sequencing. DNA was isolated from blood samples, then the variable section v3–v4 of the 16S rRNA gene was sequenced. Results: statistically significant (p<0.05) differences in the quantitative and qualitative composition of bacterial DNA in the blood of obese children compared to healthy children were revealed while maintaining the diversity of the blood microbiome as a whole. In the group of children with obesity, compared with the group of healthy children, the DNA of Proteobacteria type prevailed (p<0.0001), while the amount of isolated DNA of the Firmicutes (p=0.0009) and Bacteroidetes types were reduced (p=0.0362). Also, in children with obesity, the frequency of detection of Fusobacteria DNA was statistically significantly higher (p=0.0351) and the frequency of Thermi detection was lower compared to the same indicators in the group of healthy children (p=0.0407). Conclusion: despite the similarity in characteristics of blood microbiome diversity in healthy children and children with obesity, obesity leads to significant changes in the taxonomic composition of blood bacterial DNA already at the level of phyla.