Bile microbiota in primary sclerosing cholangitis: Impact on disease progression and development of biliary dysplasia

Primary sclerosing cholangitis (PSC) is a chronic inflammatory liver disease leading to strictures in intra- and extrahepatic bile ducts and finally to cholestasis and secondary biliary cirrhosis. The chronic inflammation is associated with increased proliferation of biliary epithelial cells and a markedly increased risk of development of biliary dysplasia and cholangiocarcinoma. The etiopathogenesis of PSC is unknown, but the frequent association with inflammatory bowel disease, in 62–83% of PSC patients, and increased intestinal permeability in PSC has suggested a role for microbiota or microbial metabolites or derivatives, e.g. pathogen-associated molecular patterns, PAMPs) such as lipopolysaccharide (LPS), lipoteichoic acid, and peptidoglycan in the etiopathogenesis of the disease. It has been proposed that the association between PSC and IBD can be due to increased enterohepatic circulation of PAMPs (“leaking gut”), or abnormal PAMPs (as a result of enteric microbial dysbiosis, described in IBD).The samples were collecting during ERCP examinations. Before injecting contrast media a bile sample was aspirated from extrahepatic bile ducts using balloon catheter. Brush cytology was routinely performed during ERC. ERC findings were scored according to the modified Amsterdam score (mAm score). Isolation, amplification and sequencing of the V1-V3 regions of bacterial 16S rRNA gene were performed on the Illumina MiSeq platform.