ABSTRACT
The aim of this paper is to establish whether there are cytochemical or ultrastructural alterations in the hepatocytes of patients with primary biliary cirrhosis (PBC) at stages I and II compared with the biopsies from individuals with normal liver. Cytochemical technique with ATP as substrate, transmission electron microscopy (TEM) and freeze fracture were used for the studies. In the normal liver biopsies the ultrastructural cytochemical localization of the enzymatic activity was clearly shown in the bile canaliculi. In the PBC biopsies, the enzymatic activity is increased in the bile canaliculi and is also present in the lateral membranes of the hepatocyte. TEM of the lateral surface of the hepatocyte in normal livers showed a smooth surface without microvilli but in PBC livers a large number of microvilli were seen in the lateral membranes. The Golgi apparatus in these patients was localized not only near the canaliculi (normal livers) but also in front of the microvilli. Freeze-fracture showed normal features in the bile canaliculus junctions of the PBC patients. We suggest that the localization of the enzymatic reaction, microvilli and Golgi apparatus at the PBC hepatocyte lateral membranes may represent a compensatory mechanism for derivation of bile flow and other components from the hepatocyte to the intercellular space.