Expression of thrombomodulin in patients with spontaneous occlusion of the circle of Willis.

Background and Purpose: We examined the expression of thrombomodulin, a recently isolated anticoagulant protein, in endothelial cells from patients with spontaneous occlusion of the circle of Willis (cerebrovascular moyamoya disease) to determine whether lack of the expression of thrombomodulin might lead to the thrombogenicity in patients with this disease.
Methods: The intracranial internal carotid arteries, the external carotid arteries, and the vertebral or basilar arteries from 12 autopsied patients who had this disease and eight control autopsied patients were examined immunohistochemically by using the antiserum against human thrombomodulin.
Results: All of the endothelial cells from the patients with this disease and from the control patients were positive for thrombomodulin. Immunoelectron microscopy also disclosed normal localization of thrombomodulin on the luminal plasma membrane. Immunohistochemically, we could find no significant differences in the expression of thrombomodulin among the arteries examined in this study.
Conclusions: We conclude that as far as we investigated immunohistochemically, the thrombogenicity in this disease is almost unlikely to depend on the abnormal expression of thrombomodulin.