MONOCYTE MACROPHAGE RECRUITMENT AND EXPRESSION OF ENDOTHELIAL ADHESION PROTEINS IN HUMAN ATHEROSCLEROTIC LESIONS/

Since mononuclear cells are recruited in atherosclerotic lesions, the expression of adhesion proteins by the arterial endothelium may play a major role in atherogenesis. The relationships between ICAM-1, E-sele ctin, and VCAM-1 expression on the arterial endothelium and the presen ce and degree of maturation of intimal macrophages in human atheroscle rotic lesions was investigated. By quantitative double immunostaining with a pan-macrophage-specific monoclonal antibody, HAM-56, and a rece ntly developed monoclonal antibody that is specific for mature macroph ages, 3MA-B38, arterial sections were classified as (I) normal, (II) t hickened without macrophage infiltration, (III) atherosclerotic with r ecent macrophage infiltration or (IV) atherosclerotic with infiltratio n of mature differentiated macrophages. A marked increase in the expre ssion of ICAM-1, E-selectin, and VCAM-1 was observed on endothelial ce lls adjacent to recently recruited macrophages. Endothelial cells over lying differentiated macrophages exhibited a lower but significant inc rease in VCAM-1 expression, with no difference in ICAM-1 and E-selecti n expression with respect to that observed in endothelium of normal ar teries. These findings indicate that the endothelium covering the huma n arterial wall exhibits different states of activation as reflected b y the expression of adhesion proteins, and that intimal monocyte/macro phage recruitment appears to depend on the level of expression of adhe sion proteins.