PLASMINOGEN-ACTIVATOR INHIBITORS (PAI-1 AND PAI-2) IN NORMAL PREGNANCIES, PREECLAMPSIA AND HYDATIDIFORM MOLE

Objective To examine the behaviour of the major inhibitors of fibrinolysis (PAI-1 and PAI-2) in normal pregnancy and pregnancy complicated by either pre-eclampsia or hydatidiform mole. Design Prospective study. Setting Antenatal Clinic and Maternity Hospital. Subjects Eleven women with established pre-eclampsia and eleven women, matched by age, parity, and duration of pregnancy who were undergoing uncomplicated pregnancy. Two women having surgery for hydatidiform mole. Main outcome measure Plasma levels of PAI-1 and PAI-2 antigens determined by sensitive specific ELISA. Functional identification of PAI-2 by nondenaturing gel electrophoresis with overlay zymography. Results In pre-eclampsia PAI-2 antigen was significantly lower than in normal pregnancy (105.3 +/- 34.9 versues 187.1 +/- 67.9 ng/ml; P<0.001). In contrast PAI-1 antigen was significantly higher in pre-eclampsia than in normal pregnancy (170.7 +/- 71.2 versus 113.8 +/- 35.6 ng/ml; P<0.05). In consequence the ratio of PAI-1/PAI-2 increased markedly in pre-eclampsia (2.5 versus 0.6). No PAI-2 was detected in plasma of women with hydatidiform moles. Conclusions PAI-2 levels fell significantly in pre-eclampsia probably as a result of decreased placental mass or function. The raised PAI-1 level in pre-eclampsia may reflect a response to hypertension or renal damage that is not specific to pregnancy or may reflect altered placental function. The use of the ratio of PAI-1/PAI-2 assists in separating normal from abnormal pregnancies.