ENHANCED TISSUE FACTOR ACTIVITY AND PLASMINOGEN-ACTIVATOR INHIBITOR-1ANTIGEN IN HUMAN UMBILICAL VEIN ENDOTHELIAL-CELLS INCUBATED WITH LIPOPROTEINS

The expression of tissue factor (TF) and plasminogen activator inhibit or (PAI)-1 was induced in cultured human umbilical vein cells (HUVEC) by very low density lipoprotein (VLDL). VLDL had a strong capacity for augmenting the expression of TF and PAI-1, while the capacity of LDL or high density lipoprotein (HDL) in this regard was very weak. VLDL a nd LDL also elevated TF activity in monocyte culture medium (VLDL, LDL ) and the conditioned medium markedly elevated TF and PAI-1 production in HUVEC compared with directly added lipoproteins. These findings in dicated that lipoproteins affect both monocyte-macrophages and endothe lial cells, and that they cause a hypercoagulable-hypofibrinolytic sta te. It is thus possible that hyperlipidaemia could be a direct risk fa ctor for thrombotic disease even if atherosclerotic lesions are not pr esent.