CULTURED RAT HEPATIC SINUSOIDAL ENDOTHELIAL-CELLS EXPRESS INTERCELLULAR-ADHESION MOLECULE-1 (ICAM-1) BY TUMOR-NECROSIS-FACTOR-ALPHA OR INTERLEUKIN-1-ALPHA STIMULATION

This study investigated the expression of intercellular adhesion molec ule-1, a leukocyte adhesion molecule, on cultured rat hepatic sinusoid al endothelial cells during stimulation with tumor necrosis factor-alp ha or interleukin-1 alpha. Using immunoelectron microscopy and the imm unogold technique against intercellular adhesion molecule-1, gold part icles were shown to increase significantly on the surface of sinusoida l epithelial cells treated with tumor necrosis factor-alpha (100 U/ml) or interleukin-1 alpha:(10 U/ml) for 8 h compared with unstimulated c ells. In addition, semi-quantitative analysis of intercellular adhesio n molecule-1 on the sinusoidal endothelial cells was performed by cyto fluorometer. Even without stimulation, intercellular adhesion molecule -1 was weakly expressed. However, 8 h after tumor necrosis factor-a or interleukin-la treatment, the expression of intercellular adhesion mo lecule-1 on cells was increased in a dose-dependent manner. Kinetic an alysis showed that the expression of intercellular adhesion molecule-1 on sinusoidal endothelial cells treated with these cytokines increase d gradually from the beginning of stimulation to 24 h. These findings suggest that hepatic sinusoidal endothelial cells may mediate the dire ct interaction between leukocytes and sinusoidal endothelial cells by expressing leukocyte adhesion molecules such as intercellular adhesion molecule-1. (C) Journal of Hepatology.