QUANTIFICATION OF THE INTRAHEPATIC BILIARY TREE DURING HUMAN FETAL DEVELOPMENT

Development and differentiation of bile ducts have been studied for th e understanding of pathogenesis of biliary atresia and other diseases of the intrahepatic biliary tree. The aim of this study is to correlat e the type of biliary structure with the size of the portal tract and the gestational age. Twenty-four human livers were studied. Fetuses we re assigned to four gestational age groups: group I, up to 20 postfecu ndation weeks (PFW); group II, from 21-26 PFW; group III, from 27-32 P FW; and group TV, from 33-38 PFW. In each specimen, 30 portal tracts w ere classified as small, medium, or large according to the diameter of the portal vein. In order to identify the bile duct cells, the sectio ns were immunolabeled with anti-cytokeratin antibody, and the biliary structure was classified as absent (bile ducts (BD) = 0), presence of bile duct cells without lumen (BD = 1), or presence of bile duct with lumen (BD = 2).In the small portal tracts, either there were no biliar y structures or just a few. There was a substantial increase in the nu mber of medium portal tracts that included a bile duct as a function o f gestational age. The majority of large portal tracts exhibited a bil e duct. In human fetus up to 20 PFW, it is possible to find 70% of por tal tracts without bile ducts, and at 38 PFW it is expected that more than 50% of the portal tract has a ED > 0. We suggest the use of the d iameter of the portal vein and the gestational age for the quantificat ion of biliary structures and the evaluation of maturity of intrahepat ic biliary tree. Anat. Rec. 251:297-302, 1998. a 1998 Wiley-Liss, Inc.