An Exploratory Study on the Pathogenic Role of Faecal Extracellular Vesicles in Metabolic Dysfunction‐Associated Steatotic Liver Disease Progression and in Drug‐Induced Liver Injury

The role of extracellular vesicles secreted by the gut microbiota present in faeces (fEVs) is not well known in metabolic dysfunction-associated steatotic liver disease (MASLD) and idiosyncratic drug-induced liver injury (DILI). We identify the microbiome profiles of fEVs in these liver diseases, and analyse the effects of fEVs from MASLD, without (F≤2) or with (F≥3) significant liver fibrosis, and DILI patients on inflammation, steatosis and mitochondrial function. DILI patients showed a consistent pattern in fEVs, characterised by a decrease in Paraprevotella and an increase in AAP99, Acinetobacter, Actinobacillus, Aerococcus and Anaeroglobus. A higher presence of 16S rDNA was observed in plasma EVs from MASLD and DILI patients. HepG2 cells treated with DILI and MASLD F≥3 fEVs increased TLR4, TLR5, IL6 and CASP3 expression, and accumulation of lipid droplets. DILI fEVs enhanced the hepatotoxic impact of diclofenac on the response to microbial components (TLR4, TLR5), inflammatory response (IL1B, IL6), accumulation of lipid droplets and mitochondrial dysfunction (OPA1, DNM1L). In conclusion, bacterial EVs enter the bloodstream and could modulate the immune response. DILI and MASLD F≥3 fEVs are drivers of the pro-inflammatory response and hepatocyte steatosis. DILI fEVs have a distinct bacterial profile that enhances the hepatotoxic potential of diclofenac.