Morphology of the endothelium over atherosclerotic plaques in human coronary arteries.

Abstract

The right coronary arteries of six hearts removed from patients with atherosclerosis, who were undergoing cardiac transplantation, were perfused with 2% buffered glutaraldehyde for 20 minutes before preparation for scanning electron microscopy. Perfusion was started within five minutes of explanation. In two patients the artery was angiographically normal, in one it was irregular in outline, and three had focal segments with significant stenosis. None of the patients had concentrations of plasma lipids above 5.5 mmol/l. The endothelial surface showed widespread focal abnormalities ranging from adhesion and migration of monocytes to loss of individual endothelial cells. Larger areas of endothelial denudation with exposure of underlying collagen were also seen consistently. Loss of endothelial cells was associated with accumulation of monocytes, on and deep to the surface, as well as adhesion of platelets to the exposed subendothelial tissue. These results accord with the endothelial damage and platelet adhesion seen in hyperlipidaemic animals fed a high lipid diet.

Delayed Recovery of Receptor-Mediated Functional Responses to Acetylcholine in Mouse Isolated Carotid Arteries following Endothelial Denudation in vivo

“…The dysfunction in the re-grown endothelial cells appears to be linked to an alteration at the level of the muscarinic receptor or associated G protein-linked cascade. In vivo, regional loss of endothelial cells has been observed over the surfaces of elevated atherosclerotic plaques [31], and spontaneous loss of endothelial cells without intimal damage has been observed in models of induced hyperhomocysteinaemia [32, 33]. Thus, the use of the PTFE filament technique may provide useful data on the processes underlying endothelial re-growth and recovery in these pathophysiological conditions.…”

Biological ageing and cardiovascular disease

“…Cellular senescence, of both the endothelium34 and smooth muscle cells,32 is an important and early feature of the atherosclerotic plaques. This is accompanied by changes in gene expression (eg, increased intracellular adhesion molecule-1 (ICAM-1) and decreased levels of nitric oxide synthase (eNOS)) that are implicated in atherogenesis 35…”

CORONARY DISEASE: The pathophysiology of acute coronary syndromes

“…Once plaque formation has progressed to stage IV, however, structural changes in the endothelium become almost universal 2. The endothelium over and between plaques shows enhanced replication compared to normal arteries, implying a degree of endothelial cell immaturity and abnormal physiological function.…”