Injury induces increase of von Willebrand factor in rat endothelial cells

This study examined the effects of injury on the content of von Willebrand factor (vWF) in rat aortic endothelium. Endothelial cells from normal, endotoxin-treated, and balloon-injured rats were stained with vWF antibodies and visualized using a biotinylated secondary antibody and avidin-tagged peroxidase. Endotoxin treatment and balloon injury caused a threefold increase in intracellular vWF, and immunoelectron microscopy showed the endoplasmic reticulum to stain heavily by the vWF antibody. Weibel-Palade bodies were not observed in all the cell profiles examined. The basement membrane of the endothelialized vessels showed no vWF staining; however, after endothelial denudation this matrix was clearly stained by the antibody. These results suggest that endothelial injury leads to an increased intracellular content of vWF that is localized primarily in the endoplasmic reticulum.