Intestinal microbiota as a non-invasive biomarker for diagnosis and prognosis of non-alcoholic fatty liver disease

Objective — to determine butyrate metabolism (via the level of butyrate­­producing bacteria) and assess qualitative and quantitative changes in the intestinal microbiota composition at the level of major phyla in patients with non­­alcoholic fatty liver disease (NAFLD) under various stress factors during wartime. Materials and methods. The study included 114 patients with NAFLD and metabolic disorders. 60 patients with NAFLD were examined during wartime, and 54 were assessed during the pre­­war period. Solid­­phase enzyme­­linked immunosorbent assay using the reagents «Insulin­­ELISA» («Hema», Ukraine), «Human BDNF ELISA Kit» (Wuhan Fine Biotech Co., China), «CRP­­ELISA» («Hema», Ukraine), «Prolactin­­ELISA» («Hema», Ukraine), «DHEAS­­ELISA» («Hema», Ukraine), and molecular­­genetic analysis of intestinal microbiota were used. Results. Quantitative determination of the butyryl‑CoA:acetate CoA‑transferase (BCoAT) gene in fecal samples may serve as a biomarker of butyrate production for individual assessment of gastrointestinal tract status and microbiota function in NAFLD patients. A significant reduction in the BCoAT gene and a decreased pool of butyrate­­producing bacteria were observed in NAFLD patients exposed to wartime stress compared to both healthy individuals and NAFLD patients examined during the pre­­war period. NAFLD patients exposed to wartime stress showed a significant imbalance in gut microbiota, characterized by an increased Firmicutes content (up to 57%) and a reduced Bacteroidetes pool (8%). The Firmicutes/Bacteroidetes ratio in these patients was nearly four times higher than in NAFLD patients examined in the pre­­war period, reaching 25.9 compared to 6.43, respectively (p <0.05). Additionally, Actinobacteria content increased to 10% compared to 7% in the pre­­war group, and other intestine bacteria rose to 25% compared to 22% during the pre­­war period. A moderate positive correlation was found between prolactin and BDNF (brain­­derived neurotrophic factor) levels and Firmicutes content, while an inverse correlation was noted between prolactin and Bacteroidetes content (p <0.05). Conclusions. Thus, based on specific microbiota and metabolite changes in NAFLD patients, the microbiota composition is expected to serve as a non­­invasive biomarker for NAFLD diagnosis and prognosis.