Age-dependent leiomuscular atrophy in vertebral arteries of individuals under low fat diet.

The volumetric density of vascular smooth muscle cells (VSMC) in the proximal vertebral artery was investigated. In order to identify VSMC, paraffin-embedded sections of the proximal vertebral artery, obtained from autopsy specimens, were immunostained for smooth muscle alpha-actin by a modified ABC-technique. The 63 autopsy specimens, including 35 males and 28 females, covered the entire range from 2 months to 85 years. The volumetric density of alpha-actin positive VSMC in the tunica media was morphometrically assayed by the point-counting method. It is important to note that the morphometrical evaluation was performed on arteries obtained from autopsy specimens of the years 1953/54, a post-war time characterized in Germany by low fat diet as compared to the present-day nutrition of most industrial nations. Probably due to their origin, the vertebral arteries showed almost no atheroma. As the main purpose of this study was to find out about the atherosclerosis-independent process of aging, these arteries seemed particularly suitable. The evaluation showed a strictly age-dependent leiomuscular atrophy which became morphometrically evident in early adulthood. The average degree of regression was measured at 0.62% per year. These results may justify the conclusion that the leiomuscular atrophy of the media represents a primary age-related process and does not in any way result as a secondary event from an atheromatous transformation of the intima.

The medicolegal significance of proteoglycans in the tunica media of the vertebral artery.

After an apparently minor blow to the neck, the vertebral artery may rupture, with a fatal outcome. It is medico-legally important to assess whether the structural state of the artery is normal and, if not, whether this abnormality contributed significantly to the individual's death. Histological confirmation of such cases is rare, as are studies of the morphology of this artery. We examined the accumulation of proteoglycans at various sites along this transitional artery in 18 subjects of different ages. There are marked age-related increases in accumulations associated with fragmentation of elastic tissue within the tunica media, with no favoured site for such changes, but with substantially fewer proteoglycans within the intracranial portion of the artery. Focal large accumulations are occasionally seen in isolated segments of arteries, with overall modest counts. We discuss implications of these findings and recommend that multiple sections of artery be examined in cases of vertebral artery rupture in order to avoid misrepresentative assessment of the structural state.

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.