SERUM PLATELET-ACTIVATING-FACTOR ACETYLHYDROLASE ACTIVITY IN NORMAL-PREGNANCY AND PREECLAMPSIA

Objective: The aim of this study was to elucidate the roles of platele t-activating factor acetylhydrolase (PAF-AH) in normal and hypertensiv e pregnancies. Method: Changes in serum PAF-AH activity were investiga ted in 13 nonpregnant women, 168 normal pregnant women, 11 women in no rmal puerperium, and 35 pregnant women with preeclampsia (mild: 28, se vere: 7). Serum PAF-AH activity was measured by the method of Staffori ni et al. Results: The serum PAF-AH activity of normal pregnant women between 5 and 34 weeks gestation was significantly lower than that of nonpregnant women, increasing after 34 weeks gestation and returning t o nonpregnant levels within 1 month after delivery. In the pregnant wo men with mild preeclampsia at 28-41 weeks gestation, serum PAF-AH acti vity (28.0 +/- 1.0 nmol/min/mL, mean +/- SEM, n = 28) was significantl y (P < 0.01) higher than that in gestational-age-matched normal pregna nt women (21.3 +/- 0.8 nmol/min/ml, n = 73). However, in the pregnant women with severe preeclampsia, the activity (12.5 +/- 3.9 nmol/min/mL , n = 7) was significantly lower (P < 0.01). Three of 7 severe preecla mptic patients showed extraordinarily low PAF-AH activity even before the onset of preeclampsia. Conclusion: We found remarkable differences between the serum PAF-AH levels in mild and severe preeclampsia. In m ild preeclampsia, the increased PAF-AH activity may play a role in reg ulation of the local PAF concentration. On the other hand, some of the women with severe preeclampsia showed extraordinarily low PAF-AH acti vity, suggesting that such a regulatory mechanism of local PAF concent ration may not operate in the patients.