Ultrastructural Aspects of the Role of the Media‐smooth Muscle Cells in Arteriosclerosis of Man and Animals

Abstract

In various arterial lesions including atherosclerotic lesions, the main morphological change involves smooth muscle cells. The potential sensitivity is different among the arterial smooth muscle cells, venous smooth muscle cells and smooth muscle cells of other organs. The modified smooth muscle cells characterized by the increase of rough endoplasmic reticula are considered to express their latent ability to synthesize collagen fibers, elastic fibers and other ground substances. The foam cells noted in atherosclerosis and fatty streak consist of lipid accumulated smooth muscle cells and hematogenous macrophages. Lipid metabolism and synthesis in the latter differ from those in the former. The ratio of the two kinds of foam cells in atheroma or fatty streak varies by the stage of the lesion. It is possible to suppose that there exists a factor which would selectively attack the media smooth muscle cells of small arteries or arterioles. This is observed electron microscopically as focal cytoplasmic necrosis (cytoplasmolysis) of smooth muscle cells and plays an important role in the histogenesis of fibrinoid necrosis. In case of experimental periarteritis nodosa the early stage begins with cytoplasmolysis of smooth muscle cells and marked increase of rough endoplasmic reticula in adjacent smooth muscle cells.

Aortic Lathyrism: Ultrastructural Study of Lesions in the Aortic Wall and the Protective Effect of Pyridinol Carbamate

“…These lesions are similar to those described by T akebayashi et al [18] during experimental arteriosclerosis and by H osoda and Iri [6,7] and H osoda and Suzu k i [8] during experimental lathyrism. Accumulations of elastin coming from preexisting and destroyed elasticbands were found in the interstitium.…”

Formation of Lipid-Laden Cells from Cultured Aortic Smooth Muscle Cells and Macrophages by Linoleic Acid Hydroperoxide and Low Density Lipoprotein

“…The origin of the cells has been assigned to smooth muscle cells of arteries [1][2][3], to macrophages derived from monocytes [4][5][6][7][8][9], or to both of them [10][11][12]. In our previous paper [13], we reported that linoleic acid hydroperoxide increases the binding of low density lipoprotein (LDL) with cultured smooth muscle cells from rabbit aorta and its degradation in the cells.…”

Ultrastructural morphometry of hypertensive medial damage in lenticulostriate and other arteries.

“…Such focal cytoplasmic necrosis of smooth muscle cell have been demonstrated by experimental means other than hypertension. These experimental means include repetitive electrical stimulation of the gastric arteries in rabbits, 5 contraction of pulmonary arterial smooth muscle cells by crotalaria alkaloid in rats, 17 and restraining stress damaging the gastric submucosal arterioles in rats. 18 Hypertonicity of the arterial musculature seems important in these experimental models.…”