An Observational Clinical Study on the Association of Intestinal Ruminococcus Gnavus and Its Derived Biogenic Amines With Metabolic Dysfunction-associated Fatty Liver Disease

1.Healthy individuals without a history of liver disease or related underlying diseases; or patients diagnosed with metabolic dysfunction-associated fatty liver disease (MAFLD) according to the latest guideline, Guidelines for the Prevention and Treatment of Metabolic (Dysfunction-Associated/Non-Alcoholic) Fatty Liver Disease (2024 Edition), meeting the following criteria: (i) imaging-based diagnosis of fatty liver and/or liver biopsy showing ≥5% macrovesicular steatosis in hepatocytes; (ii) presence of at least one component of metabolic syndrome (MetS); and (iii) exclusion of other causes of fatty liver, including excessive alcohol consumption (weekly ethanol intake ≥210 g for men and ≥140 g for women), malnutrition, hepatolenticular degeneration (Wilson's disease), and other potential etiologies.