✓ A micro-corrosion technique was used to demonstrate an extensive vasa vasorum network in extracranial vessels but did not reveal this system in intracranial vessels of comparable size in three species of animals. The absence of a vasa vasorum network in cerebral vessels may result in a higher level of susceptibility to periarterial abnormalities, such as cerebral vasospasm secondary to subarachnoid hemorrhage.
Ben R. Clower, David M. Sullivan and Robert R. Smith
John P. Kapp, Ben R. Clower, Frederick M. Azar, Nobuyoshi Yabuno and Robert R. Smith
✓ Subarachnoid hemorrhage (SAH) was produced in cats by transorbital rupture of the right middle cerebral artery (MCA). In untreated cats, widespread proliferative angiopathy occurred in both MCA's by 16 days after SAH. In cats that received systemic heparin, the pathological events following SAH were clearly reduced in the ruptured artery, and were not present in the contralateral left MCA. Platelets are known to adhere to the subintimal surface of cerebral arteries after SAH. The authors suggest that platelet-derived growth factor released from the intimal platelet carpet following SAH may be the stimulus for the development of proliferative angiopathy, and that this platelet factor is inhibited by heparin.