Timing of ICAM-I Expression in a Canine Model of Post-Haemorrhagic Cerebral Vasospasm.

SUMMARY: Temporal alterations in endothelial intercellular adhesion molecule I (ICAM-I) expression during the course of post-haemorrhagic cerebral vasospasm (PHCV) are correlated with angiographic and histologic changes in the canine basilar artery. Angiography was performed in six dogs to obtain baseline measurements of basilar artery diameter. In three dogs subarachnoid haemorrhage (SAH) was created by performing percutaneous puncture of the cisterna magna, and replacing 7 ml of cerebrospinal fluid with 7 ml of arterial blood. The remaining three dogs were used as controls. Daily angiography was performed on all dogs to determine the percent reduction in basilar artery diameter (%RBAD). One dog from each group was sacrificed after 24 hours. The remaining two dogs in each group were sacrificed after 48 hours. Each basilar artery was perfusion fixed and subjected to histologic, and immunohistochemical analysis. In the SAH group, the average %RBAD was 4 (+/- 3) at 24 hours, and 36 (+/- 1) at 48 hours. In the control group, the average %RBAD was - 1 (+/- 1) at 24 hours, and 0 (+/- 2) at 48 hours. Endothelial edema and endothelial expression of ICAM-I were found at 24 hours.At 48 hours post-SAH there was widespread endothelial desquamation, but no evidence of ICAM-I expression. In the control group, histology was normal and no ICAM-I expression was found at 24 or 48 hours. The results suggest that a brief window of therapeutic efficacy exists during the first postictal 24 hours where ICAM-I antagonists may be useful in suppressing the pathogenesis of PHCV.