The ratio of the main phylotypes of the intestinal microbiota in patients with non-alcoholic fatty liver disease against the background of obesity and its correlation with the stage of hepatic steatosis

Abstract

Objective — to study the ratio of the main phylotypes of the gut microbiota (GM) in patients with non‑alcoholic fatty liver disease (NAFLD) depending on the body mass index and its correlation with the stage of hepatic steatosis.Materials and methods. The study included 140 individuals. The main group consisted of 120 patients with NAFLD, who were divided into two subgroups depending on body mass index: I — 85 (70.83 %) patients with concomitant obesity (OB) I — III degree, II — 35 (29.17 %) overweight patients. Each subgroup was divided into two groups depending on the stage of NAFLD: A — non‑alcoholic steatosis (NAS), B — non‑alcoholic steatohepatitis (NASH). The control group consisted of 20 apparently healthy individuals. In the main group there were 59 (49.2 %) men and 61 (50.8 %) women, in the control group — 8 (40.0 %) and 12 (60.0 %), respectively. The median and interquartile range of the age of patients in the study group was 48.75 [40.5; 60.0] years, in the control group — 46.30 [35.00; 56.00] years. All patients underwent ultrasound examination of the liver, general clinical and laboratory examinations with measurement of the level of the main phylotypes (Bacteroidetes, Firmicutes and Actinobacteria) in the fecal contents by the polymerase chain reaction method in real time and calculating the Firmicutes/Bacteroidetes ratio.Results. As the result of investigation of the ratio of the main phylotypes of GM it has been revealed that in subgroup ІА (n = 34) the value of Firmicutes/Bacteroidetes ratio was 6.96 [1.57; 8.39], in subgroup IB (n = 51) — 8.68 [1.77; 10.40], in subgroup IIA (n = 26) — 5.25 [1.14; 7.37], in subgroup II B (n = 9) — 3.30 [1.17; 6.17]. Indicators in the subgroups did not differ significantly, though significantly differed from the indicator of the control group (0.64 [0.52; 1.47]). The increase in Firmicutes/Bacteroidetes ratio in the studied subgroups was associated with the enrichment of GM with bacteria of Firmicutes type: 51.91 [42.6; 64.96] %, 53.65 [41.85; 69.66] %, 48.35 [37.47; 62.99] % and 44.31 [37.43; 62.80] % in subgroups ІА, ІB, ІІА, IIB, respectively. The relative content of Firmicutes was almost the same in the subgroups, but significantly different from the indicator of the control group (34.65 [24.58; 43.53] %), and the relative content of Bacteroidetes was less and was 18.77 in subgroup IA — 18.77 [8.10; 26.09] %, in subgroup IB — 18.79 [5.78; 25.76] %, in subgroup IIA — 24.69 [8.38; 34.04] %, in subgroup II B — 25.19 [12.93; 37.44] %. According to this indicator, there was no significant difference between the subgroups, and in subgroups IIA and II B — also with the indicator of the control group (29.97 [22.52; 41.75] %). The relative number of Actinobacteria almost did not differ in the subgroups and the control group (8.66 [3.81; 9.61] %, 8.95 [2.63; 9.00] %, 5.05 [1.37; 6, 85] %, 10.80 [2.75; 17.95] % and 4.92 [2.63; 9.00] %, respectively).Conclusions. The results of the study showed that the GM composition in terms of the content of the main phylotypes was significantly different in patients with NAFLD, depending on the body mass index and the stage of steatosis, compared with the control group. There was a significant increase in Firmicutes/Bacteroidetes ratio in the subgroups compared with the control group: in NAS patients with concomitant OB — by 13.56 times, in patients with NAS with concomitant OB — by 10.87 times, in overweight patients with NASH — 8.2 times, in patients with NASH with overweight — 5.16 times. The relative content of Actinobacteria in the subgroups and the control group did not significantly differ. Analysis of the relative composition of GM did not reveal significant differences between the subgroups. In NAFLD patients with OB or overweight, the relationship between the stage of hepatic steatosis and the ratio of the main GM phylotypes was not found.