Serum angiotensin converting enzyme activity in pregnancy-induced hypertension

OBJECTIVE: Avariant of angiotensinogen gene and the renin-angiotensin system have been implicated in hypertensive disorders of pregnancy. However, the role of angiotensin converting enzyme (ACE) activity in pregnancy-induced hypertension remains controversial. Our purpose of this study was to determine ACE activity in pregnancy-induced hypertension. STUDY DESIGN: One hundred and two pregnant women with singleton pregnancies in the third trimester were studied: 43 ptire preeclamptics, 19 preeclamptics with medical complications of diabetes mellitus, asthma, or chronic hypertension, and 40 normotensives. Preeclampsia was defined by AOOCi criteria and hyperuricemia (5.5 mg/dL or >1 SD of normal mean values for gestational age). Serum ACE activity was determined by spectrophotometric analysis of the cleavage of the substrate furylacryloylphenylanalnylglycylglycine by ACE. One way analysis of variance, two-tailed t test, contingency table methods, simple linear regression and correlation were used for statistical analyses. Data are expressed as mean ±SEM. RESULTS: There were no significant differences in maternal age, parity, gestational age, and race amongst these groups. Serum ACE activity did not significantly differ amongst pure preeclamptics, preeclamptics with medical complication, and normotensives (33.8 ±2.5 vs. 35.7 ±3.5 vs. 34.3 ±2.8 U/L respectively). However, pregnant women with diabetic vasculopathy or eclampsia had a higher serum ACE activity (40.6 ±4.0 and 40.0 ±13.6 U/L respectively). ACE activity did not significantly correlate with preeclamptic severity, magnesium sulfate administration, proteinuria, serum uric acid, creatinine, or hematocrit. CONCLUSIONS: Although our data do not support the theory that ACE plays an important role in the pathogenesis of preeclampsia, elevated serum ACE activity indicates a more severe vascular disorder such as diabetic vasculopathy or eclampsia.