山梨医科学雑誌　第19巻1号　021-031(2004)

<原 著>
Binswanger型脳血管性痴呆例の大脳髄質における
血管線維症の組織学的研究

中 村 樹美枝，渡 辺 正 樹

要 旨：Binswanger型脳血管性痴呆群と対照群の大脳髄質における（1）髄質動脈の外膜肥厚度［（外膜厚/壁厚）×100］を指標とした外膜線維症の程度と分布，（2）両群の髄質動脈の走行型による形態変化の差を検討した．（1）痴呆群の外膜肥厚度は前頭葉で最も強く，頭頂，後頭，側頭葉の順で減少し，前頭葉では深部髄質が表層髄質より強かった．対照群の程度は軽かった．（2）痴呆群の皮髄境界部で彎曲する髄質動脈（R型動脈）では，髄質部の中膜筋細胞が減少して内腔は拡張し，外膜も厚く，その末梢の細血管に強い外膜線維化を見た．一方，直進する髄質動脈（S型動脈）では中膜細胞の有意な減少はなく，その末梢の細血管の外膜線維化は軽かった．対照群では両型動脈ともに中膜細胞の減少はなく，末梢の細血管線維化の程度に差はなかった．これらの結果から，痴呆群においては，髄質動脈の屈曲部遠位に生ずる血流力学的負荷増が他の筋細胞障害因子とともに，中膜細胞の減少と外膜線維化をもたらし，その末梢に広範な血管線維症と脱髄を起こし，痴呆を発症すると考えられた．よって髄質動脈の中膜筋細胞減少は本痴呆の成り立ちに重要な役割を演じていると推察できた．

キーワード Binswanger型脳血管性痴呆，髄質動脈外膜線維症，中膜筋細胞壊死，動脈腔拡張



A Histological Study on Angiofibrosis in Cerebral Medulla of Binswanger Type Vascular Dementia

Kimie NAKAMURA and Masaki WATANABE

Abstract: Grades of adventitial fibrous thickening [(adventitia thickness/wall thickness) ×100], luminal diameters and numbers of medial muscles in certain points of the medullary arteries in autopsied brains of patients with and without Binswanger type vascular dementia were measured. The adventitial fibrosis in the diseased group was more marked than that of controls, and it was severest in the frontal lobe and was decreased in the parietal, occipital and temporal lobes in this order. The fibrosis in the frontal lobe was dominant in the deep madulla. The medullary arter-ies bent at the corticomedullary junction in the diseased group showed a significant myocyte decrease with dilated lumen and thickened fibrous adventitia. The arterioles downstream of the bent arteries showed more marked arteri-olofibrosis, as compared with those of the straight medullary arteries. On the other hand these changes in the con-trols were slight even in the bent arteries. We presume that the hemodynamic load at the distal part of the bent medullary arteries may result in medial myocyte decrease, adventitial fibrosis, and luminal dilatation. Reduced vascu-lar compliance resulted from the above-mentioned changes can affect arterioles to bring extensive arteriolofibrosis, which may cause brain demyelination and ultimately produced dementia. Thus, we consider that the medial myocyte decrease of the medullary arteries may play an important role for development of Binswanger's dementia.

Key words Binswanger type vascular dementia, medullary artery adventitial fibrosis, medial muscle necrosis, luminal widening


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