Cholangio Pericytes in Periductal Fibrosis of Biliary Atresia

Abstract

Periductal fibrosis of the interlobular bile ducts of the liver was examined in 20 cases of biliary atresia (BA) . Spindle-shaped mesenchymal cells, which we regarded as cholangio pericytes, were observed in all cases around interlobular bile ducts, and concentric circular fibrosis with ductal stenosis was seen in the cirrhotic cases. Cholangio pericytes were positive for a smooth muscle actin on immunohistochemistry, which is a marker of activated fat-storing cells. Electron microscopy revealed fat-storing cells, myofbroblasts and fbroblasts in the cholangio pericytes. Fibroblasts were observed in the cases of advanced periductal fibrosis, whereas fat-storing cells and myofibroblasts were seen in the cases with no obvious periductal fibrosis. These pathological findings suggest that periductal fibrosis in BA is mediated by fat-storing cells and activated myofibroblasts. Active periductal fibrosis is considered to be a characteristic intra-hepatic disorder associated with BA.