Unique gut microbiota and metabolomic profiling as biomarker of post-transplant recovery in acute-on-chronic liver failure after liver transplantation.

Acute-on-chronic liver failure (ACLF) is a severe condition arising from chronic liver disease, characterized by acute decompensation, organ failure, and high short-term mortality. Poor outcomes have also been observed in patients with ACLF after liver transplantation (LT). Emerging evidence, including a study from our center, suggests that gut microbiota plays an important role in ACLF. Patients who underwent LT at our center between October 2022 and June 2024 were included. Fecal samples were collected within 1 month post-LT for 16S rRNA and untargeted metabolomic sequencing. In this study, 144 samples from 69 patients with ACLF, cirrhosis, or hepatocellular carcinoma (HCC) were analyzed. Distinct microbiota and metabolic profiles were observed among the groups. ACLF patients exhibited significantly altered beta diversity, with notable depletion of g__Anaerostipes. Metabolomic analysis revealed substantial differences, including enrichment of tangeritin and depletion of candesartan in the ACLF group. Network analysis identified g__Anaerostipes as a key node linking differential taxa and metabolites. A random forest model based on these features effectively distinguished patient groups, with the highest classification accuracy observed in HCC. Multi-omic signatures were also associated with early allograft dysfunction (EAD), particularly g__Lachnoclostridium. Several microbial and metabolic features, including g__Lachnoclostridium, showed significant correlations with clinical indicators. The gut microbiome after LT is closely associated with ACLF. This study offers valuable insights for further investigation into the pathogenesis and post-LT prognosis. KEY POINTS: • ACLF patients have a unique gut microbiota and metabolic profile after LT • g__Anaerostipes is the prominent biomarker of ACLF's multi-omics signature • g__Lachnoclostridium is a promising indicator of recovery after LT.