THE EXPRESSION OF THE ADHESION MOLECULES ICAM-1, VCAM-1, PECAM, AND E-SELECTIN IN HUMAN ATHEROSCLEROSIS

The expression of PECAM, ICAM-1, VCAM-1, and E-selectin was studied in 64 samples of human coronary arteries taken from 15 explanted hearts obtained within 5 min of transplantation. Normal artery (n=12), predom inantly fibrous plaques (n=23), and plaques containing extracellular l ipid (n=26) and three segments showing recanalization channels were st udied. All endothelial cells strongly and equally expressed PECAM; pos itive staining was used to check that artefactual denudation of the en dothelial surface had not occurred. PECAM was also present in some lip id-filled macrophages. Normal arteries showed no VCAM-1 staining but f ocal segments of the endothelium were positive for ICAM-1 and E-select in. ICAM-1 was strongly and constantly expressed by the endothelium ov er all types of plaques and in macrophages. E-selectin expression was confined to endothelial cells and occurred on the surface in 35 per ce nt of fibrous and 22 per cent of lipid-containing plaques. VCAM-I stai ning of surface endothelium occurred in 39 per cent of fibrous and 20 per cent of lipid-containing plaques. A population of spindle-shaped c ells of macrophage type (positive for EMB11 antigen) expressed VCAM-1 in lipid-containing plaques. Adventitial vessels adjacent to plaques s howed endothelial expression of ICAM-1 and E-selectin. VCAM-1 staining of adventitial vessel endothelium was associated with local lymphoid aggregation. In conclusion, the expression of cell adhesion molecules is an important element in the inflammatory component of atheroscleros is and contributes to both monocyte and lymphocyte activation and recr uitment from advential vessels and the arterial lumen.