Studies on Capillarization of the Hepatic Sinusoids in Alcoholic Liver Disease

It has been reported that basement membranes were found around the sinusoidal walls in cirrhotic livers, indicating the development of capillarization of the sinusoids. It has been also emphasized that capillarization of the sinusoids is more prominent in alcoholic liver disease (ALD). In the present study, factor VIII related antigen (VIII-Ag) and UEA-1 were identified immunohistochemically in order to analyze capillarization of the sinusoids in chronic liver diseases. Electron microscopic studies on the endothelial cells and sinusoids were also performed. Electron microscopic studies revealed that the number of fenestra in the endothelial cells decreased and basement membranes were clearly observed in the space of Disse from an early stage of ALD. However, these changes were not observed in the early stage of non-ALD. VIII-Ag or UEA-1 was not stainable in the sinusoidal cells of normal livers or at an early stage of non-ALD. However, in ALD, both VIII-Ag and UEA-1 were clearly demonstrated in the sinusoidal cells from the early stage of fibrosis. These results suggest that the sinusoidal endothelial cells may transform to vascular endothelial cells from an early stage of ALD. The alterations in the sinusoidal endothelium and the basement membrane formation in the Disse space indicate that capillarization of the sinusoid may occur. Capillarization of the sinusoid may cause a disturbance in exchanges of many bioactive substances between the sinusoidal blood and hepatocytes across the Disse space and may thereby contribute to the pathogenesis of ALD.