Experimental Studies on Arteriosclerosis Part 2. Histological and Histochemical Findings of Viscera

In the previous paper the author stated that the arteriosclerosis starting with atheroma degeneration of the inner coat and the arteriosclerosis of Monckeberg type both developed on account of the abnormalities in the cholesterol metabolism in the experiments in which cholesterols had been given in various amounts either orally or parenterally. From detailed histological observations in these experiments the author believes that the common findings in these two are the basic pathological changes such as the swelling of muscular fibers and accompanying fat degeneration, decompositions of glycoproteins, and that these changes are none other than the reflection of the metabolic disturbances in the course of pathological changes. In his experiments with rabbits orally given cholesterols, after precise histological investigations, Leary offers an interesting theory concerning arteriosclerosis that the atheroma degeneration of the aorta is caused by the atheroma formation resulting from the fact that the libar reticulo-endothelial cells after ingesting lipids, deposit themselves on the aortic wall and invade below the endothelial-cell layer of the aorta-inner coat. There are opinions both for and against this hypothesis, and the author has also taken a keen interest in this theory. In this connection the author studied in detail pathological changes in the viscera of the rabbits in which arteriosclerosis had been induced variously by adminstering a large or a small amount of cholesterols orally or intravenously as reported in the previous paper, and arrived at the following conclusions: 1) Arteriosclerosis is one of the signs reflecting the disorders in the fat metabolism in the internal organs of the whole body. It is not a disease solely involved in the arterial system. 2) In the case where the metabolic disorder is progressing rapidly, the artery reveals mainly the sclerorsis of the medionectrotic type along with the degeneration or atrophy of the viscera; and in the case where the metabolic disorders appear gradually, the degeneration is rather of a secondary nature and the formation of foam cells plays a main role and the sclerosis of atheroma-degeneratiion type appears in the artery. 3) Foam cells do not originate only from the reticulo-endothelial cells, but they also originate from reticulum cells, arterial smooth-muscle cells, renal tubular eptithelial cells, interstitial cells of ovarium, and adrenocortical cells; and foam cells of a simillar shape are derived from these various cells, and they tend to conglomerate at one site, forming a mass of cells. Histologic findings on the foam cells found in the region of atheromatosis degeneration of the aorta suggest that these cells are derived from the smooth-muscle cells or fibrocytes in the aorta tissue, but not from the reticuloendothelial cells of liver