Gut microbiome composition and metabolic activity in metabolic-associated fatty liver disease

Metabolic Associated Fatty Liver Disease (MAFLD) impacts approximately 25% of the global population. Between April 2023 and July 2023, 60 patients with MAFLD, along with 60 age, ethnicity, and sex-matched healthy controls (HCs), were enrolled from the Inner Mongolia Autonomous Region, China. Analysis of gut microbiota composition and plasma metabolic profiles was conducted using metagenome sequencing and LC-MS. LEfSe analysis identified five pivotal species: Eubacterium rectale, Dialister invisus, Pseudoruminococcus massiliensis, GGB3278 SGB4328, and Ruminococcaceae bacteria. In subgroup analysis, Eubacterium rectale tended to increase by more than 2 times and more than double in the non-obese MAFLD group, and MAFLD with moderate hepatic steatosis (HS), respectively. Plasma samples identified 172 metabolites mainly composed of fatty acid metabolites such as propionic acid and butyric acid analogues. Ruminococcaceae bacteria have a strong positive correlation with β-alanine, uric acid, and L-valine. Pseudoruminococcus massiliensis has a strong positive correlation with β-alanine. Combinations of phenomics and metabolomics yielded the highest accuracy (AUC = 0.97) in the MAFLD diagnosis. Combinations of phenomics and metagenomics yielded the highest accuracy (AUC = 0.94) in the prediction of the MAFLD HS progress. Increases in Eubacterium rectale and decreases in Dialister invisus seem to be indicative of MAFLD patients. Eubacterium rectale may predict HS degree of MAFLD and play an important role in the development of non-obese MAFLD. Eubacterium rectale can generate more propionic acid and butyric acid analogues to absorb energy and increase lipid synthesis and ultimately cause MAFLD.