Abstract
Although periductal fibrosis is a well-known risk factor for progressive hepatic fibrosis in biliary atresia, the fibrogenic process is not well understood. Histological examination was used to determine the cell type responsible for periductal fibrosis in biliary atresia. Hepatic specimens were obtained by radical operation of 20 patients with biliary atresia, ranging in age from 1 to 4 months. Alpha smooth muscle actin and CD34 antibodies were used as probes in immunohistochemical labeling experiments. In all cases, cytoplasm stained positive for alpha smooth muscle actin. The number of cells in the CD34 positive peribiliary capillary plexus was greater in BA patients, and the capillaries had more frequent connections with periductal mesenchymal cells. Electron microscopy revealed that spindle-shaped mesenchymal cells, regarded as periductal mesenchymal cells, surrounded the interlobular bile duct in 16 cases, and were occasionally located in spaces between the capillaries and bile duct epithelia. These results suggest that periductal mesenchymal cells are derived from pericytes of the peribiliary capillary plexus in biliary atresia.
