| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1998: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
Background: Artery size varies according to both the wall thickness and the composition in the carotid or coronary arteries. Cerebral arterio(lo)sclerosis, especially medial necrosis is regarded as a major contributing factor for hypertensive intracerebral hemorrhage, lacunar infarcts or multi-infarct dementia. The aim of this study was to investigate both the modality of the wall adaptation (morphologic remodeling) to the cerebral arterio(lo)sclerosis and the topographic distribution of the medial necrosis in the cerebral arterial trees.
Methods: Seventeen autopsy brains of patients with hypertension (HT) and 21 without HT were investigated light- and electron-microscopically. The morphometric study was carried out by means of computer-assisted analysis system (OZ95). The intracerebral arteriosclerotic trees were reconstructed three-dimensionally.
Results and Conclusion: In the arterial cross sections having less than 40% stenosis, there were a highly significant linear relationship bet
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ween intimal thickening and arterial enlargement at the definite location of distal ICA, MCA (M2), intracerebral perforating arteries and long medullary arteries. When wall tensile stress (TS) was calculated using only medial thickness (MT), values ranged from 10.9 to 17.1 x 1OィイD15ィエD1dyne/cmィイD22ィエD2. However, when total thickness(intimal thickness+MT) was used, TS was almost similar at all levels(range, 6.5 to 7.2 x 10ィイD15ィエD1). Then the wall TS is stabilized by the total wall thickness though the artery enlarged. However, we couldn't demonstrate the relationship in the small arteries less than 200 μ m in diameters showing medial necrosis or atrophy without stenosis, which is characteristic of hypertension. That may be why the cerebral small arteries are easily disrupted and result in hemorrhage. Three-dimensional reconstruction revealed that medial necrosis had a tendency to locate near bifurcation in the perforating arteries. This suggests that the pathogenesis of medial necrosis may be related to hemodynamic forces. Less
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