Fibrinolysis during Normal Pregnancy and Severe Preeclampsia Relationships between Plasma Levels of Plasminogen Activators and Inhibitors

Abstract

The antigen levels of plasminogen activator inhibitor type 1 (PAI-1), plasminogen activator inhibitor type 2 (PAI-2), tissue-type plasminogen activator (t-PA), and urokinase-type plasminogen activator (u-PA) were measured during pregnancy and severe preeclampsia. The PAI-1 and PAI-2 antigen levels increased linearly during pregnancy and promptly returned to the level of non-pregnant women after delivery. The t-PA and u-PA antigen levels increased slowly and linearly during pregnancy. In severe preeclampsia, the PAI-2 antigen level was lower than that observed during the 3rd trimester of normal pregnancy, and the t-PA antigen level was higher than that during the 3rd trimester of normal pregnancy. Immunohistochemical examination of placental tissue showed that the PAI-2 and u-PA antigens were localized in syncytiotrophoblasts. In severe preeclampsia, the PAI-2 and u-PA antigens in placental tissue did not stain as clearly as during the 3rd trimester of normal pregnancy. The PAI-2 and u-PA antigen levels showed a positive correlation with birth weight. Therefore, PAI-2 may be an important marker of placental function and abnormality in pregnancies.