Summary
Plasminogen activators are inhibited by plasminogen activator inhibitors-1 (PAI-1)
and -2 (PAI-2). We describe the synthesis of PAI-2 by human vascular endothelial cells
(EC) cultured from umbilical vein, saphenous vein and foreskin microvasculature in
response to interleukin-1α (IL־1α) and tumour necrosis factor α (TNFα) and compare
it with that of PAI-1. Both PAI-2 and PAI-1 were quantitated by ELIS As. PAI-2 was
cell-associated while PAI-1 was secreted by EC. IL-lα and TNFα increased the synthesis
of PAI-2 and PAI-1 by EC in a dose-dependent manner. IL-1α was a stronger stimulus
for PAI-2 synthesis than TNFα, while both cytokines were equally effective for PAI-1.
Northern blot analysis revealed similar changes in mRNA levels to those in antigen
levels. PAI-2 synthesis by cytokine-stimulated EC may be important in thrombus formation
and inflammation.
