Abnormal hepatic expression of fibrillin-1 in children with cholestasis.

Abstract

Fibrillin-1, one of the main constituents of microfibrils, is present in normal adult liver and overexpressed in fibrotic area around cirrhotic nodules and hepatocellular carcinoma. In this work fibrillin-1 expression was studied by immunohistochemistry in liver samples from children with various cholestatic diseases corresponding to paucity of intrahepatic bile ducts, biliary atresia, congenital hepatic fibrosis, Byler's disease, mitochondrial cytopathy, sclerosing cholangitis, or choledochal cyst. As controls, histologically normal liver samples were used. In control liver, as in adult, fibrillin-1 was expressed in vessel walls, sinusoids, and portal connective tissue, particularly at the interface with the limiting hepatocytic plate and close to the basement membrane of bile ducts. In paucity of intrahepatic bile ducts without fibrosis, the fibrillin-1 distribution was similar to controls. In cholestatic diseases associated with severe fibrosis, such as biliary atresia, congenital hepatic fibrosis, Byler's disease, mitochondrial cytopathy, or sclerosing cholangitis, an enhanced deposition of fibrillin-1 was observed in portal connective tissue and fibrous septa. The strong fibrillin-1 expression close to the basement membrane of biliary structures was lost in cholestatic diseases, except biliary atresia. Finally, in normal and pathologic tissues, fibrillin-1 was co-localized with its putative receptor alphaVbeta3 in sinusoids but not around biliary structures.