Assessment of the functional state of gut microbiota in patients with metabolic-associated fatty liver disease in combination with type 2 diabetes mellitus

Abstract

Background. The purpose of the study was to assess the functional state of gut microbiota in patients with metabolic-associated fatty liver disease (MAFLD) combined with type 2 diabetes mellitus (T2DM). Materials and methods. The prospective interventional randomized study included 71 patients with MAFLD in combination with T2DM, who were examined and divided into the 2 groups. The first group included 39 people with MAFLD and T2DM without small intestinal bacterial overgrowth (SIBO). The second group consisted of 32 patients with MAFLD in combination with T2DM and SIBO. The control group included 25 practically healthy patients. The content of serum zonulin was determined by enzyme-linked immunosorbent assay (ELISA) using test systems IDK Zonulin ELISA, KR5601. Serum concentration of interleukin (IL) 6 and IL-10 was assessed by the ELISA method using the Human Interleukin 6 and 10 ELISA Kit test systems. The content of short-chain fatty acids in feces was determined by gas chromatography with mass spectrometry in the PerkinElmer Clarus 680 GC Gas Chromatograph. Results. Patients of the first and second groups had an increase in hepatic aminotransferases, total cholesterol, triglycerides, fasting blood glucose, insulin, HOMA-IR, glycosylated hemoglobin, serum zonulin, leptin, IL-6 and liver attenuation coefficient and a decrease in high-density lipoprotein. The results of steatometry revealed a severe degree of hepatic steatosis (S3) in patients with MAFLD combined with T2DM and SIBO and without SIBO. During the quantitative study of the level of butyric acid in feces, it was found to be significantly reduced, by 2.3 times in the first group and by 3.4 times in the second one, compared to the controls (p < 0.001). The content of butyric acid was decreased by 1.4 times in the second group compared to the first one (p < 0.001). When evaluating the level of acetic acid, it was found to be significantly increased compared to the controls, by 1.2 times in the first group and by 1.3 times in the second one (p < 0.001). The concentration of propionic acid was increased by 1.3 times in the first group and by 1.5 times in the second one compared the control group (p < 0.05). When comparing the level of acetic acid, a significant increase by 1.3 times was observed in patients of the first and second groups compared to patients of the control group (p < 0.001). The content of propionic and acetic acids was increased by 1.1 times in the second group compared to patients of the first group (p < 0.05). When analyzing the correlation coefficients in patients with MAFLD combined with T2DM and SIBO and without SIBO, a direct proportional strong correlation was revealed between the levels of butyric, acetic and propionic acids and serum zonulin, IL-6, IL-10. A direct moderate correlation was found between the content of short-chain fatty acids and leptin, indicators of lipid metabolism (total cholesterol, triglycerides), carbohydrate metabolism (fasting blood glucose, HOMA-IR, HbA1c) and inverse weak correlation with high-density lipoprotein. A direct moderate correlation was revealed between levels of short-chain fatty acids and indicators of functional activity of the liver (alanine aminotransferase, aspartate aminotransferase), liver attenuation coefficient in patients with MAFLD combined with T2DM and SIBO and without SIBO. Conclusions. Increased intestinal permeability and hyperleptinemia have been found in patients with МAFLD combined with T2DM and SIBO and without SIBO. When studying the functional state of the gut microbiota, an increase was found in propionic and acetic acids and a decrease in butyric acid, which indicates an increase in the number of Bacteroidetes in the intestine and a decrease in Firmicutes. Patients with MAFLD combined with Т2DM and SIBO and without SIBO had a direct proportional strong correlation between the levels of butyric, acetic and propionic acids and serum zonulin, IL-6, IL-10, which is associated with pro-inflammatory and anti-inflammatory processes in the intestinal mucosa and a violation of the permeability of the intestinal barrier. It was found that concentrations of short-chain fatty acids correlate with indicators of functional activity of the liver (alanine aminotransferase, aspartate aminotransferase), leptin, indicators of carbohydrate and lipid metabolism, degree of hepatic steatosis.