IL13 and periostin in active fibrogenic areas of the extrahepatic bile ducts in biliary atresia patients

Background: The leading pathology of biliary atresia (BA) is inflammatory and fibrous obstruction of extrahepatic bile duct, but the pathogenesis remains unclear. IL13 is a cytokine associated with allergies and inflammatory fibrosis, and periostin induces fibrogenesis by stimulation with IL13. We analyzed the involvement of IL13 and periostin in inflammatory fibrosis in the extrahepatic bile duct of BA patients. Materials and methods: Surgically resected tissues from the hepatic hilar area of BA patients were immunostained with CD45, α-SMA, IL13 and periostin and statistically analyzed. Fibroblasts from the resected tissue were cultured with recombinant IL13, and periostin production was analyzed by quantitative polymerase chain reaction and Western blotting. Results: IL13 was stained in 93% of large and micro bile ducts, and 92.1% matched with the CD45 location (p = 0.006) around the large bile ducts. Periostin staining correlated with the localization of IL13 and αSMA (p < 0.001) around the large bile ducts. Periostin mRNA and protein were upregulated by IL13 stimulation in cultured fibroblasts. Conclusion: IL13 was associated with induced periostin expression by fibroblasts, playing a vital role in the pathogenesis of fibrogenesis around the extrahepatic bile duct in BA.