Immunomorphological aspects of formation of an intracranial aneurysm

: An immunohistochemical study of the arteries of the circle of Willis and the walls of ampullar aneurysms indicated the impaired expression of the matrix proteins collagens I, III, and V in the aneurysms. Examination of the proliferative activity of cell elements in different parts of the aneurysmal sac showed a significant activation of proliferative processes along the cervical parts of aneurysms and the presence of proliferating cells in the body and fundus of aneurysms different in sizes. The findings suggest that the magnitude of proliferative and synthetic processes plays a definite role in the formation of an aneurysmal sac and in the so-called growth of aneurysms.