Effect of lipoproteins on tissue factor activity and PAI-II antigen in human monocytes and macrophages.

Expression of the tissue factor (TF) and the plasminogen activator inhibitor-II were induced in cultured human monocytes-macrophages by incubation with lipoproteins. Very low-density lipoprotein (VLDL) augmented the TF and PAI-II expression the most, followed by low-density lipoprotein (LDL) and a very weak effect by high-density lipoprotein (HDL). In macrophages pre-cultured for 3 days, oxidized LDL augmented the expression of TF activity in the macrophages to a greater extent than native LDL. These findings indicate that lipoproteins affect both monocytes and macrophages, and that they induce a hypercoagulable-hypofibrinolytic state. Thus hyperlipidemia may be a direct risk factor for thrombotic disease.