Human Atherosclerosis: Comparative Study of Mononuclear Infiltration in Aorta, Coronary and Cerebral Arteries

Abstract

Atherosclerotic involvement of aorta and large arteries depends on a variety of factors. In the last decade, literary data have accumulated about the role of mononuclear cellular infiltration (MCI) in atherogenesis (Kohchi et al., 1985; Masuda and Ross, 1990; Ross, 1993; Stary, 1990; Stratford et al., 1986). The aim of the present study is to parallel intimal and adventitial MCI in human atherosclerotic aorta, coronary and cerebral arteries. In 59 autopsy cases (21 women and 38 men, between 30 and 85 years of age), segments from aorta, left anterior descending branch, basilar and each middle cerebral arteries were processed and stained routinely for light microscopy and analyzed for MCI location and density. In the 472 arteries harvested from all 59 autopsy cases a total of243, both early and late atherosclerotic lesions were observed, among them: fatty streaks - 46(18, 63%), fibrofatty change - 33 (13, 58%) and fibroatheroma - 164 (67, 79%). MCI in the intima are presented either as single cells, or as small groups of cells beneath the endothelium. Adventitial MCI are found usually as small groups; in aorta they often encircle vasa vasorum; in the coronary arteries MCI also involve the perivascular nerve fibers, or the newly formed blood vessels. In the cerebral arteries MCI are not widespread. The presence of MCI does not correlate with the lesion type. Most of the lesions are not accompanied by any MCI and, on the contrary, massive MCI are found in early lesions and occasionally even in normal vessels. The semiquantitive analysis shows most frequent involvement of aorta, almost equally for intima and adventitia; while in coronary and cerebral arteries the adventitia is predominantly involved. As the present material demonstrates the most severe and fatal forms of human atherosclerosis it is tempting to suggest that MCI are responsible at least for the activation of the atherosclerotic process.