Activity of platelet-activating-factor-acetylhydrolase and the nitric oxide metabolite level in the plasma of pregnant women who develop transient hypertension during later pregnancy

Abstract

It is reported that plasma platelet-activating-factor-acetylhydrolase (PAF-AH)is elevated in patients with essential hypertension. In this study, plasmaPAF-AH activity was measured during pregnancy and after delivery to examinethe relationship between plasma PAF-AH activity and the development oftransient hypertension (TH) during pregnancy. Moreover, in order to examinethe involvement of endothelial injury in TH, the plasma level of nitric oxidemetabolite (NOx; NO<emph type="8">2+NO<emph type="8">3) wasmeasured. The plasma PAF-AH activity in 51 pregnant women was consecutivelymeasured in the 1st, 2nd and 3rd trimesters of gestation, and after delivery.Forty-one cases were normal pregnancies and 10 cases were complicated by THlater during pregnancy. The PAF-AH activity in the normal pregnancy groupdecreased in the 2nd trimester of gestation compared with the 1st trimester,but was elevated in the TH group. The incidence of elevation of PAF-AH in theTH group was significantly (7/10; 70.0%;P&lt;0.01, Chi-squared test) higher than in the normalpregnancy group (9/41; 22.0%). The plasma NOx levels in the 2ndtrimester were higher than those in the 1st trimester in both the normotensiveand TH group (P&lt;0.05 for both comparisons). The 51patients were classified into two groups according to the change in the PAF-AHin the 2nd trimester: group A consisted of 35 patients whose PAF-AH activitydid not increase, and group B consisted of 16 patients whose PAF-AH activityincreased. The incidence of development of TH during later pregnancy in groupB was significantly (7/16; 43.8%; P&lt;0.01,Chi-squared test) higher than in group A (3/35; 8.6%). Hypertensiondeveloped after 36 weeks&rsquo; gestation in all patients in the TH group. Theresults of the present study suggest that changes in PAF metabolism may relateto regulation of blood pressure in pregnant women whose pregnancy iscomplicated with TH, whereas NO metabolism does not differ between women withTH and those having a normal pregnancy.Extra keyword: PAF-acetylhydrolase