Scanning electron microscopy of arteries. The morphology of aortic endothelium in haemodynamically stressed areas associated with branches.

The endothelial surface around branches of the normal rabbit aorta was examined by scanning electron microscopy (SEM). Focal endothelial damage was consistently found both on, and distal to, aortic flow dividers. In some case small areas were denuded of endothelial cover. Similar injury to endothelal cells was also occasionally observed proximal to the ostium of a branch. Haemodynamic forces, expecially high shear stress, may be responsible for these morphological changes. This altered endothelial integrity probably underlies the susceptibility of these sites to the formation of induced atherosclerotic lesions.