Effects of angiotensin II on the expression of PAI-1 and tPA in cultured human umbilical vein endothelial cells

Objective To observe the effects of angiotensin Ⅱ(AngⅡ) on plasminogen activator inhibitor-1(PAI-1) and tissue type plasminogen activator( tPA) releasing and their activity in cultured human umbilical vein endothelial cells(HUVECs). Methods Several groups of cultured HUVECs were incubated with AngⅡ of 1×10-9~1×10-6 mol/L for 24 hours or with 1×10-6 mol/L AngⅡ for various times up to 24 hours.Then the antigens and activity of PAI-1 and tPA in the cultured medium were measured by enzyme linked immunosorbent assay(ELISA) and the indirect chromogenic assay. Result Compared to control,1×10-9~1×10-6 mol/L AngⅡ could markly induce the increase of PAI-1 antigen[(280±16) ng/ml vs (83±11) ng/ml,P0.05,1×10-6 mol/L] and activity [(10.35±1.47) U/ml vs (5.65±0.44) U/ml,P0.01,1×10-6 mol/L] in a dosedependent manner compared to control; the increase of tPA antigen induced by AngⅡ were less than the increase of PAI-1[Δ(31±6) ng/ml vs Δ(197±21) ng/ml,P0.01].Various concentration of AngⅡ had seldom effect on tPA activity compareded with control [(0.97±0.05) U/ml vs (0.95±0.08) U/ml,P0.05,1×10-6 mol/L]. When HUVECs were cultured with 1×10-6 mol/L AngⅡ for 0~24 h,PAI-1 antigen[(224±17) ng/ml vs (9.7±1.9) ng/ml,P0.01,24 h] and activity [(10.2±0.8) ng/ml vs (1.1±0.4) ng/ml,P0.01,24 h]were increased in a time dependent manner compared to control;tPA activity had no change [(0.95±0.10)U/ml vs(1.00±0.04)U/ml,P0.05]. Conclusion AngⅡ could stimulate the release of PAI-1 and tPA and increase the activity of PAI-1.The antigen of PAI-1 were much more than those of tPA. The activity of tPA had seldom any change by AngⅡ stimulating.