Immunohistochemical studies on tenascin in extrahepatic bile duct remnants of biliary atresia

The expression of tenascin in the extrahepatic bile duct remnants in biliary atresia was investigated using an immunohistochemical method. Tenascin is thought to be a marker of repair of injured tissues based on an immunohistochemical study of a variety of tissues. Twenty-three specimens were obtained from 23 cases (2 correctable type and 21 non-correctable type) of biliary atresia at the time of the definitive operation. Positive tenascin staining was observed in matrices surrounding degenerated epithelium of the bile ductules in the obliterated extrahepatic bile duct. Regarding the correlation between the size of the bile ductule and the degree of positive staining, the larger diameter bile ductules tended to show a higher degree of positive staining. Furthermore, regarding the correlation between the degeneration of epithelium and the degree of staining, the bile ductules with the more significantly denuded epithelium tended to show a higher degree of positive staining. In some specimens classified as non-correctable type, a lumen larger than 1 millimeter in diameter without epithelium was observed. This ductule itself was thought to be the original extrahepatic bile duct because strong tenascin staining was observed surrounding this lumen. These findings suggested that the extrahepatic bile duct might be obliterated after the completion of the hepatobiliary tree system and the bile ductules in the obliterated extrahepatic bile duct might be degenerated in order of their size.