Elastic elements in the media and adventitia of human intracranial extracerebral arteries.

Abstract

SUMMARY We find that the media and adrentitia of adult human cerebral arteries contain elastic fibers forming a dense, coherent network, similar to that found in muscular arteries of the same size in other organs. The external elastic layer in the adult human is masked for the currently employed staining methods. By treatment with 90% formic acid before fixation, the original staining character of elastic tissue can be restored. The light microscopic and scanning electron microscopic features of this network of elastic fibers are presented.Stroke, Vol 11, No 4, 1980THE ELASTIC MATERIAL in intracranial extracerebral arteries is almost all concentrated in the internal elastic layer, in contrast to the muscular arteries of other organs, whose media and adventitia contain abundant elastic fibers in an outer layer. 1 The susceptibility of the cerebral arteries to injury, as well as the frequent occurrence of aneurysms in these vessels have been attributed partly to this peculiar distribution of the elastic material.*"'In the arteries of the circle of Willis and its large branches at birth, Hassler and Larsson' found a few medial and adventitial elastic fibers. Their number per unit volume increased up to the age of 2 years. The fibers formed a clearly defined external elastic layer in 20% of the children examined, only an incoherent loose "pile" in 70%, and scarcely any in 10% over each of the intimal cushions encountered. The density of the external elastic fibers appeared to decrease markedly with increasing age. Only their remnants were found in about 10% of the adults above 30 years of age, mainly in the vertebral and basilar arteries, and at times, over atheromatous areas in the more distal arterial branches. However, Wolff" has called attention to the fact that the meningeal arteries facing the cranium contain elastic elements in their media and adventitia throughout life. Crompton 4 pointed out that lack of an external elastic layer is restricted to the arteries of the adult human brain, and the intracranial extracerebral arteries in various animals have a well developed network of elastic fibers located mainly in the boundary zone between the media and adventitia. All these statements are based on the observation of histologic preparations fixed, embedded and stained in the usual manner.In a study of agents used for the isolation of elastin' on non-fixed blood vessels, we found that the media and adventitia in the arteries of the adult human brain do contain elastic elements in large amounts. Material and MethodsThe circle of Willis and its main branches, together with short sections of their cortical branches, were dissected before fixation from the base of the brain in 40 unselected patients at autopsy. Their ages ranged from 7 to 80 years with 5 collected for each decade. Arteries with atheromatous changes visible to the naked eye were not studied.The following portions of the arteries were dissected and reserved for the usual histologic procedures: 1) the right internal carotid artery with its bifurcati...

Intracranial-Derived Atherosclerosis Assessment: An In Vitro Comparison between Virtual Histology by Intravascular Ultrasonography, 7T MRI, and Histopathologic Findings

“…In comparison to extracranial vessels, the intracranial vessels have a more prominent internal elastic layer and less advanced adventitia and media. 30 Only preliminary data regarding the clinical application of plaque characterization are available. Preliminary data suggest the existence of a nonatherosclerotic variant involving the anterior circulation that may be prone to high rates of restenosis after stent treatment.…”

Cerebral arteriovenous malformations. Part 1: cellular and molecular biology

“…Mature vessels express laminin more consistently and contain little to no fibronectin in their matrix. 23,32,61,65,82,87,102 The presence of laminin in AVMs probably contributes to the resilience of these vessels in the face of hemorrhage compared with CMs (immature vessels), which are prone to repetitive microhemorrhages.…”

Cavernous Angioma Associated With Arteriovenous Malformation of the Brain -Case Report-

“…7,8,15,16,18,20) This protein is thought to sustain the structural integrity of the vessel wall by anchoring endothelial cells to the underlying internal elastic membrane and smooth muscle layers. 8,15,17) Laminin occurs predominantly in the maturation phases of angiogenesis. 15,16,20) In our case, the cavernous angioma and the AVM had similar expression patterns of laminin, as shown in Table 1.…”