AIMS/BACKGROUND:

Extracellular matrix (ECM) may affect the function and phenotype of hepatocytes. Phenotypic changes of hepatocytes in diseased liver were investigated with reference to ECM composition.

METHODS:

Immunohistochemistry was performed on biopsied liver samples from chronic viral hepatitis (CVH), primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and normal patients, using monoclonal antibodies for laminin, type IV collagen, cytokeratin 19 (CK19) and epithelial glycoprotein (EGP), a protein homologous to nidogen.

RESULTS:

In normal controls, both EGP and CK 19 were expressed exclusively on biliary epithelia. Laminin and type IV collagen were expressed around portal bile ducts and blood vessels. Although type IV collagen was expressed in Disse's space, laminin was scarcely expressed. In all pathological livers, both EGP and CK 19 were expressed in proliferated bile ductules. In CVH with piecemeal necrosis, EGP was expressed on periportal hepatocytes, while CK19 expression was limited to a few hepatocytes. Laminin was expressed in Disse's space of periportal sinusoids, where EGP was expressed on hepatocytes. EGP expression on hepatocytes and laminin deposition in Disse's space were rare in PBC and PSC liver.

CONCLUSION:

These results suggest that hepatocytes transform into a phenotype similar to biliary epithelia and, laminin deposition in Disse's space (capillarization of sinusoids) may play a role in this phenotypic change.