Some observations on reticular fibers in the media of the major cerebral arteries. A comparative study of patients without vascular diseases and those with ruptured berry aneurysms.

In spite of the large number of papers about the changes in the cerebral arterial wall occurring under various conditions, no systematic study can be found in the literature on the reticular fibers surrounding the smooth muscle cells of the media. The histologic examination of the major cerebral arteries of 70 individuals without vascular diseases revealed a dense network of fine reticular fibers in the media showing a rather uniform distribution. This pattern did not change significantly from birth up to the age of 50 years and was independent of intimal proliferation with aging. Contrary to this, all the major cerebral arteries of 35 patients who died from rupture of berry aneurysms under the age of 50 contained a considerably smaller amount of reticular fibers, predominantly in the outer part of the media. It is concluded that people having few reticular fibers in their arterial wall are susceptible to develop aneurysms, and the partial lack of these fibers may play an important role in the development of cerebral aneurysms.