Enhanced procoagulatory activity (PCA) of human monocytes/macrophages after in vitro stimulation with chemically modified LDL *

Abstract In cultured human monocytes/macrophages, surface expression of procoagulatory activity (PCA) was induced by chemically modified LDL (acetyl-LDL and MDA-LDL) in a dose- and time-dependent manner. Maximum PCA (30-fold increase) was detected after 24 h of culture with modified LDL at doses of 25–750 μ protein/ml. Using factor VII deficient human plasma and phospholipase C this PCA was identified as tissue thromboplastin activity (factor III). These results suggest a further atherogenic potential for modified LDL through stimulation of the conversion of fibrinogen to fibrin in the atheromatous lesion.