Changes in gut microbiota in patients with metabolic-associated fatty liver disease

Abstract

Background. Modern science considers changes in the gut microbiota as a pathogenetic factor in the development of many di­seases, including metabolic-associated fatty liver disease (MAFLD) and liver steatosis. Although dysbiosis is present at every stage of fatty liver disease, typical signs have not been identified separately for MAFLD that determines the relevance and expedien­cy of our research. This investigation purposed to evaluate the state of the gut microbiota in patients with MAFLD. Materials and methods. In total, 19 patients were observed. Among them, 14 had metabolic syndrome and MAFLD and 5 were without metabolic syndrome with intact liver. These two groups differed significantly only in body mass index, had similar gender-age distribution, blood pressure, parameters of lipid and carbohydrate metabolism. Metagenomic analysis of the intestinal microbiome was performed by polymerase chain reaction in a certified laboratory in addition to standard cli­nical and laboratory examinations. Patients were treated and exa­mined according to regulatory documents and the Declaration of Helsinki. Digital results were processed statistically, the level of significance was p < 0.05. Results. In patients with MAFLD, the changes in the gut microbiota began already at the stage of steatosis. They manifested by an increase in the total bacterial mass by a third, a lower number of obligate strains (Lactobacillus, Bifidobacterium, Bacteroides thetaiotaomicron, Akkermansia muciniphila) and an increased content of opportunistic pathogens (Сlostridium perfringens, Klebsiella pneumoniae, Klebsiella oxytoca, enterоpathogenic Escherichia coli, Shigella, Proteus, Salmonella) in contrast to patients with an intact liver. The bulk of bacterial DNA were DNA of Bacteroidetes (50.66 % compared to intact liver; Δ = +8.29 %) and Firmicutes (31.97 ± 3.19 %; Δ = –10.87 %) and Actinobacteria DNA (Δ = +40.41 %) made up 7.47 ± 2.69 %. Changes in the metagenomic status of the gut microbiota are associated with body weight, systemic blood circulation, lipid and carbohydrate metabolism. Conclusions. Alterations in the gut microbiota with an increase in total bacterial mass, a lower number of obligate and increased amount of opportunistic strains already at the stage of steatosis have been shown to correlate with the development and progression of fatty liver disease due to metabolic effects.