Protective and aggressive bacterial subsets and metabolites modify hepatobiliary inflammation and fibrosis in PSC.

Objective: Conflicting microbiota data exist for primary sclerosing cholangitis (PSC) and experimental models. Goal: Define complex interactions between resident microbes and their association in PSC patients by studying antibiotic-treated specific pathogen-free (SPF) and germ-free (GF) multi-drug-resistant 2 deficient (mdr2-/-) mice. Design: We measured weights, liver enzymes, RNA expression, histological, immunohistochemical and fibrotic biochemical parameters, fecal 16s rRNA gene profiling, and metabolomic endpoints in gnotobiotic and antibiotic-treated SPF mdr2-/- mice and targeted metagenomic analysis in PSC patients. Results: GF mdr2-/- mice had exaggerated hepatic inflammation and fibrosis with 100% mortality by 8 weeks; early SPF autologous stool transplantation rescued liver-related mortality. Broad-spectrum antibiotics and vancomycin alone accelerated disease in weanling SPF mdr2-/- mice, indicating that vancomycin-sensitive resident microbiota protect against hepatobiliary disease. Vancomycin treatment selectively decreased Lachnospiraceae and short-chain fatty acids (SCFAs) but expanded Enterococcus and Enterobacteriaceae. Antibiotics increased cytolysin-expressing E. faecalis and E. coli liver translocation; colonization of gnotobiotic mdr2-/- mice with translocated E. faecalis and E. coli strains accelerated liver inflammation and mortality. Lachnospiraceae colonization of antibiotic pre-treated mdr2-/- mice reduced liver fibrosis, inflammation and translocation of pathobionts, while Lachnospiraceae-produced SCFA decreased fibrosis. Fecal E. faecalis/ Enterobacteriaceae was positively and Lachnospiraceae was negatively associated with PSC patient clinical severity Mayo risk scores. Conclusions: We identified specific functionally protective and detrimental resident bacterial species in mdr2-/- mice and PSC patients with associated clinical outcomes. These insights may guide personalized targeted therapeutic interventions in PSC patients.