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 inh ibitor-II were induced in cultured human monocytes-macrophages by incu bation with lipoproteins. Very low-density lipoprotein (VLDL) augmente d the TF and PAI-II expression the most, followed by low-density lipop rotein (LDL) and a very weak effect by high-density lipoprotein (HDL). In macrophages pre-cultured for 3 days, oxidized LDL augmented the ex pression of TF activity in the macrophages to a greater extent than na tive LDL. These findings indicate that lipoproteins affect both monocy tes and macrophages, and that they induce a hypercoagulable-hypofibrin olytic state. Thus hyperlipidemia may be a direct risk factor for thro mbotic disease.