Pericanalicular hepatocytic and bile ductular microfilaments in cholestasis in man.

The cytoplasmic microfilaments of hepatocytes in the pericanalicular area and of bile ductular cells in various types of human cholestasis were examined and compared with those seen in the noncholestatic human liver. An increase in the number of hepatocytic microfilaments with an increase in the apparent density of the filamentous network and in the thickness of bundles of filaments was evident in the vicinity of the bile canaliculi, in the pericanalicular ectoplasm, and in the surrounding cytoplasm in all types of cholestasis but more so in intrahepatic cholestasis. This increase in the number of microfilaments was also seen around undilated canaliculi. Microfilaments were also increased in number beneath the surface of the bile ductular cells facing the cytoplasm but not beneath the rest of the plasma membrane. More microfilaments also were found around ductular cell nuclei. No striking differences were noted between intrahepatic and extrahepatic cholestasis. These findings suggest that microfilaments play a role that is not established in human cholestasis.