The structure of the centriolar apparatus of the endothelial cells in the embryonic and definitive human aorta

The fine structure of the centriolar system was studied on serial sections of 90 endothelial cells of human aorta (50 to 60 years) in regions without atherosclerotic platelets and with fibrous and atheromatous platelets and of 30 endothelial cells of human embryonic aorta (22-24 weeks). The vast majority (95%) of endothelial cells of the atheromatous platelets were shown to have a primary cilium over 1 micron long which gives on the basal surface in all the cells. In the regions without platelets and with fibrous platelets a cilium was observed in about 20% of cells and it gives in the vessel lumen. Endothelial cells with a cilium fully embedded in the cytoplasm and with abnormal cilium structure were found in the embryonic aorta. A suggestion is put forward that cilia of the endothelial cells of embryonic aorta and those of adult aorta differ by the mechanism of their formation and can have different functions.