Gut microbiota in non-alcoholic fatty liver disease: Pathophysiology, diagnosis, and therapeutics

Non-alcoholic fatty liver disease (NAFLD), also referred to as metabolic-associated fatty liver disease, is among the most prevalent chronic liver conditions. In some cases, NAFLD may lead to liver inflammation and non-alcoholic steatohepatitis, which can eventually progress to liver cirrhosis and hepatocellular carcinoma. The pathophysiology of NAFLD is complex, involving both genetic and environmental factors. NAFLD is a multisystem disease linked to a higher likelihood of developing metabolic disorders such as type 2 diabetes, obesity, and cardiovascular and chronic kidney diseases. The gut-liver axis represents a key connection between the gut microbiota and the liver, and its disruption has been linked to NAFLD. Growing evidence underscores the significant role of gut microbiota in the onset and progression of NAFLD, with alterations in the gut microbiome and impaired gut barrier function. Studies have identified key microbiota signatures and metabolites linked to NAFLD, implicating oxidative stress, endotoxemia, and inflammatory pathways that further strengthen the connection between gut microbiota and NAFLD. Modulation of gut microbiota through diet and microbiota-centered therapies, such as next-generation probiotics and fecal microbiota transplantation, holds promise for treating NAFLD. In this review, we explore the key link between gut microbiota and the development and progression of NAFLD, as well as its potential applications in the diagnosis and treatment of the disease.