Ultrastructural study on microvasculature of portal tract in chronic hepatitis

With special reference to portal veins

Abstract

The ultrastructure of portal veins in the portal tract of the liver in 15 patients with HBspositive chronic hepatitis was studied and compared with normal controls.
The portal veins examined in normal liver and chronic hepatitis were less than 80μm in diameter and belonged to their terminal branches. In normal liver the ultrastructure of the portal veins was similar to that reported in the literature, and neither a endothelial fenestra nor a interendothelial gap was observed. In chronic hepatitis one or more fenestrae were found in the endothelial cytoplasm. Such fenestrae were usually 20-500nm in diameter with or without a diaphragm. There was no formation of interendothelial gaps in the endothelial lining. In the fenestrated area of the portal vein, the subendothelial space was irregularly dilated and contained electron-dense flocculent material similar to that seen in the vessel lumen. This material was observed also outside the basement membrane that appeared interrupted. Mononuclear cells, predominantly lymphocytes migrated in the subendothelial space. These findings suggest that, in chronic hepatitis, the inflammatory infiltration in the portal tract takes plae through these fenestrae of the portal vein.
The portal veins with afore-mentioned changes were observed in 2 of 5 patients with CPH (or 2 of 14 portal veins examined on an electron microscope) and in all five patients with CAH 2A and 2B (or 17 of 25 and 14 of 21 portal veins respectively). Such abnormalities of the portal veins were significantly more frequent in both CAH 2A and 2B than in CPH, but not significantly different between CAH 2A and 2B.