2014 Volume 7 Issue 1 Pages 32
Backgrounds and aims: Most vascular endothelial cells are continuously exposed to shear stress in vivo. Caveolae, omega-shaped membrane invaginations on endothelial cell (EC), also are plasmalemmal domain enriched in cholesterol, caveolins, and signaling molecules. Previous studies have proposed a role for caveolin(CAV)-1 in the regulation of angiogenesis and sinusoidal differentiation. This study was designed to elucidate the ultrastructural localization and change in CAV-1 expression on human liver sinusoidal endothelial cells (LSECs) during the progression of cirrhosis, using sections prepared by perfusion fixation method.
Methods: Normal control and Child-Pugh A and C cirrhotic liver specimens by surgical procedure were studied. CAV-1 protein and gene expression was examined by immunohistochemistry, Western blotting, laser-capture microdissection (LCM)-PCR. For immunoelectron microscopy, CAV-1 expressions in sinusoid was examined by perfusion fixed liver tissue.
Results: In control liver tissue, CAV-1 was localized on caveolae mainly in arterial and portal endothelial cells of the portal tract, and was also found on vesicles and some fenestrae in LSECs around the central vein. In cirrhotic liver tissue, aberrant CAV-1 expression was observed on caveolae-like structures and a few vesicles in LSECs. Significant overexpressions of CAV-1 at protein and mRNA level in cirrhotic liver was demonstrated by Western blotting and LCM-PCR (p<0.01 Child-Pugh A and C vs control, p<0.01 Child-Pugh A versus C).
Conclusion: CAV-1 was strongly expressed on caveolae-like structures and vesicles on LSECs in the sinusoids of cirrhotic liver, suggesting an association of CAV-1 with angiogenesis and differentiation of LSECs in cirrhosis
