Abstract
Morphometric studies of endothelial cells on the aortic surface of flow dividers of aortic branchings to brachiocephalic (BC) and subclavian (SA) arteries were performed in either normo- or cholesterol-fed rabbits using scanning electron microscopy.
The cells of BC in the sudanophilic region were variously ellipsoidal, and somewhat round. All of the ellipsoidal cells were arranged multidirectionally, presumably caused by separation of the blood flow. The region was located just downstream from the leading edge covered by elongated fusiform endothelial cells arranged in alignment and parallel to blood flow. The apex of the flow divider, or stagnation point was covered by round cells. SA had also the sudanophilic region covered by ellipsoidal endothelial cells, which was downstream from the stagnation point which was not coincidental with the apex of the flow divider of SA. The areas covered by either round or elongated fusiform cells were free from lipid deposition.
It can be concluded that the sudanophilic lesions in hyperlipidemic rabbits would evolve where endothelial cells might be exposed to moderately mean low shear stress, either laminar (SA) or turbulent (BC). Hence the high shear theory of atherogenesis of animals should be reexamined.
