Histopathological and ultrastructural study of carotid atherosclerotic plaques: a study of four cases

Abstract

To clarify the characteristics and origin of the cellular components in atherosclerosis, carotid atherosclerotic plaques (CAPs) of four patients were studied by light microscopy using hematoxylin-eosin, Congo red and alpha-smooth-muscle actin stains, and by transmission electron microscopy of different regions of CAPs. By light microscopy, CAPs were composed of 1) a fibrous cap; 2) an atherosclerotic core presenting focal fibrosis, neovascularization, hemorrhage, necrosis, chondrification and ossification; and 3) a basal band composed of a hyperplasic pseudo-media and affected tunica media. Ultrastructurally, the CAPs contained a diversity of cells including fibroblasts, myofibroblasts, osteochondrocytes, vascular smooth-muscle cells, foam cells and other myoid cells characterized by varied features of the above mentioned cells. The results indicated that CAPs were derived from a proliferation of multipotential mesenchymal stem cells, leading to the presence of degenerated foam cells and lipid-laden cells.