Cholangiocyte cilia are abnormal in syndromic and non-syndromic biliary atresia

Biliary atresia is a neonatal disorder characterized by aggressive fibroinflammatory obliteration of the biliary tract. Approximately 20 percent of biliary atresia patients demonstrate left-right laterality defects (syndromic biliary atresia). Cilia participate in important physiologic functions in cholangiocytes, and since some ciliopathies have been associated with both laterality defects and hepatic fibrosis, we hypothesized that patients with syndromic biliary atresia exhibit abnormalities of cholangiocyte cilia that disrupt cholangiocyte homeostasis. Nine biliary atresia specimens were studied, including pre-Kasai diagnostic biopsies (n=7) and liver explants (n=2). Five specimens were from patients with laterality defects. These were compared to normal pediatric livers as well as livers affected by primary sclerosing cholangitis, Wilson’s disease, and cardiac cirrhosis. Biopsy sections were stained with antibodies against keratin 19 (a cholangiocyte marker) and acetylated α-tubulin (a cilia marker) and were visualized by confocal microscopy. Computer-assisted relative quantification was used to compare staining of cilia within bile ducts among samples. Surprisingly, cilia in biliary atresia specimens were significantly shorter, abnormal in their orientation, and less abundant compared to normal liver and disease controls regardless of the presence of a laterality defect. CONCLUSION: There are significant abnormalities of cholangiocyte cilia in both syndromic and non-syndromic biliary atresia livers compared to normal livers and livers affected by other cholestatic diseases. While this may result from severe cholestasis or inflammation, it may also reflect common mechanistic pathways in different forms of biliary atresia and may have important implications for understanding the progression of the disease.