Abstract
The existence of large endothelial cells in the human aorta, especially on atherosclerotic lesions has been reported. They have multiple nuclei and are called “multinucleated variant endothelial cells (MVECs)”. In the present study caveolin expression was demonstrated in both MVECs and small typical endothelial cells (TECs). Caveolin was expressed diffusely as fine particles, and caveoles were expressed as prominent accumulations of caveolin in the cytoplasm. LDL was bound to the endothelial surface. With double immunostaining for caveolin and LDL, the location of LDL corresponded to the immunoreactive caveoles. Over time, large dots of LDL appeared in MVECs, whereas a few fine particles remained in TECs. An electron microscopic chase study of LDL-gold uptake identified many LDL-gold particles in plasmalemmal vesicles and in endosomes or lysosomes of MVECs, but only a few particles were found in TECs. Gold containing vesicles often were located near the abluminal surface. The number of LDL-gold particles was 4.5 times greater per unit area in MVECs than in TECs. Some of the gold particles were located in the subendothelial collagen matrix. These findings indicate that MVECs have a greater capacity of LDL cholesterol uptake followed by transport to the subendothelial matrices than TECs, and that MVECs contribute to the development and advancement of atherosclerotic lesions.
