In an attempt to analyze the relationship between atherosclerosis and the function of the thyroid glands, 3 regions of the aorta of 26 male rabbits were studied histopathologically and histochemically. Animals were divided into 6 groups. Group I: As the control, the rabbits were maintaind on a normal rabbit food (Oriental Kobo Co. Ltd.) for 12 months. Group II: The animals received lanolin per os on each day for 12 months. Group III: The animals were thyroidectomized and received lanolin each day for 6 months. Group IV: The thyroidectomized animals received daily lanolin feeding for 12 months. Group V: The thyroidectomized animals received daily lanolin feeding and thyroxin injection for 6 months, followed by maintenance on lanolin feeding for 6 months. Group VI: The thyroidectomized animals received lanolin feeding and thyroxin injection each day for 12 months. The following results were obtained. No atherosclerosis (intimal fatty necrosis) was recognized in the aorta of rabbit in Group II, which showed only fatty streaks of the in the intimal tissue. Remarkable atherosclerosis was observed in the aorta of the thyroidectomized rabbit in groups III and IV. Intimal fibrosis without fatty necrosis was seen in the aorta of rabbit in group V. In none of the animalsin group VI was an aorta ever found with atherosclerosis or fibrosis. These observations apparenthy indicate the presence of an intimate association between atherosclerosis and the functional state of the thyroid. Deficiency of thyroid hormone induces atherosclerosis in the aorta of lanolin-jed rabbits. Thyroid hormone supplementation caused a disappearance of the atheromatous lesions in these animals, although repartory changes, characterized by intimal fibrosis. were still recognizes.
Auther attempted to analyze the relationship between the atherosclerosis and the function of the thyroid glands, and coronary arteries, arteries of choroid plexus and endocrine glands of the rabbits ultilized in previous experiment (Report I) were studied histopathologically. The following results were obtained: No atherosclerosis (intimal fatty necrosis) was recognized in the coronary arteries and arteries of choroid plexus of th rabbits which were received lanolin feeding for 12 months, and they showed only the fatty streaks in the intimal tissue. Remarkable atherosclerosis were observed in the intimal tissue of the coronary arteries and arteries of choroid plexus of the rabbits which were received thyroidectomy followed by lanolin feeding for 6 months or 12 months. A small atheromatous lesion were recognized in the coronary artery of the thyroidectomized rabbit which received lanolin feeding and thyroxin injections for 6 mouths, after they had been maintained on a lanolin feeding for 6 months, however, proliferation of intimal spindle shaped cells were seen around and within the atheromatous lesion, and these cells did not show any regressive changes. It will be considered that these intimal spindle shaped cells have a role of reparative adsorbtion of the atheromatous necrotic substance. These observation indicate that intimate associations between atherosclerosis and the functional state of thyroid glands exist. Deficieney of thyroid hormone induce athrosclerosis by means of lanolin feeding in the rebbit artery, and the thyroid hormone supplementation caused a disappearance of the atheromatous lesions from rabbit artery, however, did exhibit reparatory changes, characterized by intimal fibrosis. The observations concerning with endocrine glands were as follows: In the rabbits received only lanolin feeding, the thyroid glands exhibited findings of hyperfunctional state, a slight proliferation of chromophobe cells and alfa cells were also recognized in hypophysis, hyperplasia of islets cells of Langerhans were seen in pancreas, and the cortex of adrenal glands showed slight atrophy. When the animals were received thyroidectomy and lanolin feeding, remarkable proliferation of chromophobe cells and beta cells were seen in hypophysis. Hyperplasia of islets cells of Langerhans were seen in the pancreas, and atrophy of the cortex of adrenal glands were also found in this group. In the thyroidectomized rabbits received lanolin feeding and thyroxin injection after they had been maintained on a lanolin feeding, chromophobe cells and beta cells of hypophysis, islets cells of Langerhans of pancreas whih had proliferated in the period of lanolin feeding were exhibited observations of gradual atrophy by thyroxin supplementation.
Despite many epidemiological and pathological studies on the etiology of cerebral apoplexy, the relationship between findings of ocular fundi and cerebral apoplexy has still remained obscure. The author has studied on the significance of findings of ocular fundi, especially pathologic changes of the retinal artery, in predicting cerebral apoplexy. In the present study pathologic findings of the branches of the intracerebral artery, and those of retinal arteries were correlated with aging process and blood pressure. One hundred and one male and one hundred and thirty eight female cases between ages of 45 days to 94 years autopsied at the branch hospital of the University of Tokyo and at Yokufukai Hospital were randomly employed for the present study. The retinal arteries within 7 or 8 disc diameter, small intracerebral arteries and arterioles in the area of basal ganglia were histologically and histometrically studied. Hypertrophy, atheromatous degeneration, and calcification in the intima, as well as thickness, fibrosis or hyalinization, calcification and angionecrosis in the media were described. Results and conclusions were as follows; 1) Hypertrophy in the media of retinal arteries probably developed as the result of hypertension. 2) Fibrosis in the media of the retinal arteries was apparently due to aging and enhanced by hypertension. 3) Hypertrophy in the intima of branches of the intracerebral artery was mainly due to aging, but enhanced by hypertension. 4) Angionecrosis of branches of the intracerebral artery was mainly due to aging, and enhanced by hypertension, but other factors such as aging and some renal factors might also be concerned with the development of angionecosis of these arteries.
The author studied on the abnormality of the lipid composition in arteriosclerotic patients and on the arteriosclerotic changes of the lipids in aged rats. Furthermore, the effects of VB2 Butyrate on arteriosclerosis were studied. In the serum of arteriosclerosis, triglycerides was increased. On the other hand, in the serum fatty acid composition there was an increase in the proportion of oleic acid and a decrease. of linoleic and arachidonic acids. L/O ratio was also decreased. In the tissue of atheroma with calcification, total cholesterol was increased remarkably and there was an increase in the proportion of linoleic acid in the fatty acid composition. There was on remarkable difference between the serum lipid concentrations between aged and young rats. In the tissue of aortic wall, however, there was an increase of cholesterol in the aged rats. However, in the fatty acid composition of the aged rats, there was an obviouly increasing proportion of oleic acid and the decreasing proportion of linoleic and arachidonic acids. L/O ratio was decreased. The changes of the aged rat serum and aorta were almost the same as the changes of the serum lipids in arteriosclerotic patients. It was found that there was the same tendency of a decrease of arachidonic acid proportion in the serum, aortic wall of arteriosclerotic and aged rats. As the control group, naturally aged rats, fed with high fat and low protein diet along with cholesterol and thiouracil to accelerate arteriosclerosis were used. The other group was given the same diet with addition of VB2 Butyrate to inhibit the sclerotic changes. As a result, the lipid composition in the serum and tissue of aortic wall of the rats fed with VB2 Butyrate containing diet was normalized. Administrating VB2 Butyrate on arteriosclerotic patients, a decrease of the serum triglycerides and that of serum cholesterol were observed. In the fatty acid composition, an increase in the proportion of linoleic and arachidonic acids was found.