Circulating endothelial cells fail to induce cerebral infarction in rabbits.

Exfoliated cells that appear to be circulating endothelial cells were detected in human blood. Because the size of endothelial cells is larger than that of other circulating blood cells, we investigated whether the increased number of circulating endothelial cells might be responsible for cerebral embolism. We compared rabbits into which suspensions of endothelial cells were injected through the common carotid arteries with control rabbits into which blood clots or arachidonic acid were administered in the same manner. Injected endothelial cells failed to cause cerebral embolism. Because the majority of exfoliated circulating endothelial cells were degenerated and deformed, the suspensions of endothelial cells obtained from rabbit aortas were treated by ultrasonic waves. These suspensions also failed to cause cerebral embolism. We conclude that cerebral embolism cannot be induced by an increase of circulating endothelial cells alone.