In the study of the lesion of the arterial system ranging from the aorta to peripheral arterioles, it is important to give consideration to the size of the artery, its region and the nature of change.
Generally arteriosclerosis is represented by atherosclerosis. However, it is rather infrequent that the atheromatous changes of the aorta and its main branches are directly related to the cause of death. Important are sclerotic changes of relatively small arteries. Such changes are hardly atherosclerosis but mostly Jore's ‘elastisch-hyperplastische Intimaverdickung’ or hyaline thickening. Moreover, arteriosclerosis shows great difference by individual and even in the same individual by the region or the organ. Therefore, it is required to take these facts into consideration when studying the relation between hypertension and arteriosclerosis.
The authors conducted the studies on the relation between hypertension and arteriosclerosis by two methods. In the first method, autopsy cases ranging in age from 20 to 90 whose blood pressure before death was available classified into hypertension group and normal pressure group and the changes of the middle-sized mesenteric arteries and of the small renal, pancretic and myocardial arteries and arterioles were compared.
In relatively large arteries such as the superior mesenteric arteries, the main change was proliferative fibrous thickening of intima which advanced in degree with the increase of age but there was hardly any difference between the hypertension group and normal pressure group. On the other hand, changes in small arteries or arterioles showed close relation with the blood pressure. Intimal thickening was closely related with the blood pressure rather than to the age. Marked intimal thickening was noted even in young subjects of the hypertension group.
In the second method, hypertension was classified into three types, namely, essential, renal and adrenal, and each type of hypertension was examined in relation to the vascular changes. In this method, subjects were limited to those under age 40 in order to minimize the factors of vascular changes due to aging.
Atheromatous changes of aorta showed no difference between the hypertension group irrespective of type and the normal pressure group. Middle-sized arteries showed marked intimal thickening in some hypertensive cases such as middle-sized myocardial arteries in essential hypertension.
Vascular changes showing a narrowing were not necessarily due to intimal thickening. In middle-sized renal and myocardial arteries and arterioles, hyperplasia of media was one of the factors of vascular stenosis.

View full abstract

The epidemiological study demonstrates that the incidence of atherosclerotic disease is more closely related to the level of serum cholesterol rather than the degree of high blood pressure in the population with higher level of serum cholesterol, while that is more significantly attributable to the tatter than the former in the population with lower level of serum cholesterol.
There is also the fact that the incidence of atherosclerotic disease tends to increase in parallel with the higher level of blood pressure in a given population regardless of the level of serum cholesterol.
It is concluded, therefore, that high blood pressure could play an important role for the development into atherosclerosis.

View full abstract

Changes of acid mucopolysaccharides (Glycosaminoglycans) of the aorta were studied in the control rats and spontaneously hypertensive rats (Okamoto-Aoki).
The amount of uronic acid, chondroitin sulfate, heparan sulfate and hyaluronic acid was measured by the method described previously (J. Atheroscl. Res. 7, 83, 1967).
Inorganic sulfate³⁵ (3mc/Kg. Body weight) was given intraperitoneally 24 hours before sacrifice and incorporation of S³⁵ into the sulfated mucopolysaccharides was also measured by use of scintilation counter.
The content of uronic aicd, chondroitin sulfate and heparan sulfate in the aorta was increased significantly in the spontaneously hypertensive rat when compared with that of the control rats. However, specific activity (S³⁵ cpm/μg of chondroitin sulfate and/or heparan sulfate) was not increased, and rather decreased in the hypertensive rats (55 weeks old).
The relationships between acid mucopolysaccharides, hypertension or atherogenesis were discussed.

View full abstract

Relations between blood pressure and arteriosclerosis were discussed clinicopathologically and experimentally. Clinicopathological study was made on the aged over 60 year-old in Yokufukai Geriatric Hospital. Incidence of cerbral haemorrhage and cerebral infarction increased parallel with the severity of hypertension. Incidence of myocardial infarction, however, was unrelated to blood pressure. The severity of cerebral arteriosclerosis had a significant positive correlation with the averages of both systolic pressure and diastolic pressure. The severity of coronary arteriosclerosis was correlated only with the average of systolic pressure. The value of total serum cholesterol was apparently related to the severity of coronary arteriosclerosis. A positive significant correlation was demonstrated between systolic pressure and the total atherosclerotic area of the aorta. A negative significant correlation was demonstrated between diastolic pressure and the area of complicated lesions. The grade of arteriolosclerosis was severer in hypertensive aged than in normotensive aged. Systolic blood pressure had highly significant correlation with the severity of the sclerotic change in both small arteries and arterioles of the kidney. Diastolic pressure had also significant correlation with sclerotic change of the small arteries. The effects of blood pressure on the changes of arterial connective tissue, especially acid mucopolysaccharide, were experimentally studied on rabbits. A marked increase of total acid mucopolysaccharides in the aorta was found in rabbits with high blood porssure, which were produced by constricting abdominal aorta or renal artery with a silver clip. Increase of chondroitin sulfate, decrease of hyaluronic acid and increase of sulfate contents in acid mucopolysaccharides were demonstrated in hypertensive aorta. There was a positive correlation between blood pressure level and total mucopolysaccharide contents in the aortic wall. Acid mucopolysaccharide has been considered to play an important roll in the arteriosclerotic process. So our results suggest that the hypertension induces the changes of arterial mucopolysaccharides, and may prepared the ground for the developement of arteriosclerosis.

View full abstract

1) The contribution of hypertension to risk of cerebral hemorrhage, cerebral infarction and myocardial infarction was examined in 427 elderly autopsied cases. The diastolic hypertensive group had significantly higher incidence rates of severe cerebral sclerosis, cerebral infarction, cerebral hemorrhage, severe coronary sclerosis, hearts above 350gm, and moderately large myocardial scar and myocardial infarction than the normotensive group below 160mmHg systolic and 90mmHg diastolic. Between the normotensive group and the systolic hypertensive group (systolic pressure>160mmHg) a definite difference was noted only in the incidence of severe cerebral arteriosis. Except for cerebral infarction, significant differences were observed between the systolic hypertensive group and the diastolic hypertensive group. In comparison to the group with a diastolic blood pressure from 90mmHg to 110mmHg that with a diastolic blood pressure≥110mmHg had a significantly greater incidence rate of cerebral hemorrhages.
2) In our previous reports vascullar permeability factors were demonstrated in the renal cortex. These factors ware quite different from renin and the intravenous injection of the factors resulted in the development of small cerebral hemorrhages in rats. The blood level of these factors were measured by the use of hemagglutination inhibition test. Cases of fresh cerebral hemorrhage had higher blood levels of the permeability factor than those with old cerebral hemorrhage.
3) Membrane potential of rat muscle immediately decreased when the permeability factor prepared from rat kidney was added to the medium. This was not the case for inactivated permeability factor. From these data it is concluded that hypertension accelerates arteriosclerosis and that the renal permeability factor is an important factor contributing to the manifestation of cardiovascular complications and the development of arterischerosis.

View full abstract

Effects of LCAT on hyperlipidemia are very interesting. To study LCAT reaction on lipoprotein metabolism in the normal state, the followings were studied: location of LCAT in the blood, esterification of cholesterol in lipoproteins by LCAT, relationship between LCAT activity and serum lipoprotein concentration, lipid concentration and the degree of obesity in 130 of healthy controls.
LCAT activity was assayed by Glomset and Akanuma's method and lipoprotein concentration was measured by the ultracentrifugation method.
LCAT was the most active in Density>1.210g/ml protein and the degree of LCAT activity was gradually in Density>1.210g/ml protein fraction>in high density lipoprotein₃ (HDL₃)>in high density lipoprotein₂ (HDL₂)>in low density lipoprotein (LDL), in very low density lipoprotein (VLDL).
Furthermore, LCAT in the protein had activity sufficiently in the substrate-lipoprotein.
It seemed that LCAT is not necessarily combined with lipoproteins in the blood.
On the other hand, concerning to the substrate of LCAT reaction, HDL (especially HDL₃) was supposed to be the most effective substrate.
Significant positive correlations were observed between LCAT activity and VLDL, LDL, total cholesterol, esterified cholesterol, unesterified cholesterol, triglyceride, phospholipid levels and the degree of obesity.
Because of this observation in the normal state, it is suspected that LCAT activity may not affect lipoprotein and lipid concentrations but rather lipoprotein and lipid concentrations may affect LCAT activity.

View full abstract