Pii: S0021-9150(00)00454-8

Inhibitors of HMG-CoA reductase, namely statins, improve endothelial function independently of their cholesterol-lowering effects. Plasminogen activator inhibitor type-1 (PAI-1) plays a critical role in vascular pathophysiology both at the intraand extravascular levels. We therefore investigated the effects of atorvastatin (ATOR) and fluvastatin (FLU) on PAI-1 and also tissue-type plasminogen activator (t-PA) synthesis in 20% fetal calf serum-cultured human umbilical vein endothelial cells (HUVEC) stimulated or not by recombinant human pro-inflammatory cytokines, i.e. tumor necrosis factor a (TNFa) and interleukin 1a (IL-1a). In non-stimulated HUVEC, ATOR and FLU significantly diminished (−50% at 2.0 mmol/l) the constitutive production of PAI-1 (mRNA level and protein secretion). This effect was prevented by addition of mevalonate (100 mmol/l). In HUVEC cultivated in 20% fetal calf serum, the t-PA antigen accumulation was not significantly altered, whereas in low serum concentration (1%) a significant stimulatory effect of ATOR (+30%) and FLU (+76%) was observed. In TNFa-stimulated cells, ATOR and FLU had a modest down-modulating effect (−17 and −20%, respectively) on TNFa-induced increase in PAI-1 synthesis. No effect of statins was observed in IL-1a-stimulated HUVEC, suggesting that statins do not interfere with the up-regulation of PAI-1 synthesis by pro-inflammatory cytokines. However, ATOR and FLU inhibited the TNFa-induced decrease in t-PA release. In conclusion, these results show that statins favorably modulate the expression of fibrinolytic factors produced by human endothelial cells. © 2000 Elsevier Science Ireland Ltd. All rights reserved.