STUDY ON PATHOGENESIS OF CEREBRAL CHANGES OF VASCULAR DEMENTIA BASED ON HYPERTENSION

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07457056
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Experimental pathology
• Research Institution: MEDICAL RESEARCH INSTITUTE,TOKYO MEDICAL & DENTAL UNIVERSITY
• Principal Investigator: OKEDA Riki MEDICAL RESEARCH INSTITUTE,TOKYO MEDICAL & DENTAL UNIVERSITY,PROFESSOR, 難治疾患研究所, 教授 (70013977)
• Co-Investigator(Kenkyū-buntansha): MATSUO Takashi MEDICAL RESEARCH INSTITUTE,TOKYO MEDICAL & DENTAL UNIVERSITY,ASSISTANT PROFESSOR, 助教授 (00165771) ; KUROIWA Toshihiko MEDICAL RESEARCH INSTITUTE,TOKYO MEDICAL & DENTAL UNIVERSITY,ASSISTANT PROFESSOR, 助教授 (80129832)
• Project Period (FY): 1995 – 1996
• Keywords: Binswanger's encephalopathy / Vascular dementia / Cerebral medullary artery / One kidney DOCA-salt hypertension / Hypertension

Research Abstract

Aims of this research is to investigate (1) what kind of changes does occur in the cerebral medullary arteries of Binswanger's encephalopathy (BE) of autopsy cases? ; are these hypertension-related? ; and if so, are these significantly more severe than those of hypertensive brain hemorrhage (HBH)? and (2) what kind of influences of chronic hypertension does occur in brain arteries of cats?
Material & methods : 1. As for investigation of cerebral medullary arteries, the superior frontal gyrus including cingulate gyrus from 6 cases of typical type of BE and 5 cases of HBH was serially cut with thckness of 4 to 5 mu to 700 slices. Every five slices were stained with elastica-Masson staining and changes of the medullary arteries were semiquantitatively evaluated. 2. As for influences of hypertension on the brain arteries, one kidney DOCA-salt hypertension was induced to 11 adult cats for 4 months. After sacrifice and perfusion fixation, the kidney and brain were histologically observed. The length of the internal elastic lamina and media cross-section area of a rectangularly cut artery in these slices were morphometrically measured, and the radius and thickness of the media of this artery in distended state were caliculated.
Results and discussion : 1. Pathological changes found in the cerebral medullary arteries of BE consisted of atherosclerosis of the intima and/or media, intimal fibrosis or elastofibrosis, intimal plasma exudation, microaneurysm, medial loss, adventitial fibrosis and luminal dilatation, which covered and exceeded those found in the arteries of HBH.Especially, medial loss with or without above-described intimal changes was significantly frequent in BE than in HBH,which preferentially occurred in the cortex and superficial layr of the white matter. Moreover, adventitial fobrosis was also more prominent in BE than HBH,but this change seemed to be secondary to the proximal changes such as medial loss. 2. Experimental chronic hypertension induced medial thickening of small renal arteries having radius under 40 mu only in cats with the blood pressure elevation over 34.6 mmHg. The brain arteries of cats in this group, however, did not show medial thickening. Therefore, 4-month hypertension does not influence on the brain arteries in cats.