title: PP135. Maternal serum levels of endothelial nitric oxide synthase and ADMA, an endogenous ENOS inhibitor in pregnancies complicated by severe preeclampsia.
abstract: BACKGROUND
  Preeclampsia is a major cause of maternal and fetal mortality and morbidity. Preeclampsia remains amongst the biggest challenges in obstetrics, but its aetiopathogenesis is still unclear. Recent observations support the hypothesis that imbalance between maternal angiogenic/anti-angiogenic factors concentrations is responsible for the clinical manifestations of the preeclampsia. It was also suggested that clinical manifestations of preeclampsia caused by endothelial malfunction including insufficient production of nitric oxide and that abnormality in nitric oxide synthesis or NO bioavailability may contribute to the development of preeclampsia. But the mechanism associated with alteration of nitric oxide formation in pregnancies complicated by preeclampsia is not well understood.
  
  
  OBJECTIVE
  The aim of this study was to determine the maternal serum concentrations of endothelial nitric oxide synthase (eNOS) and its endogenous inhibitor, asymmetric dimethylarginine (ADMA) in pregnancies complicated by severe preeclampsia in comparison with healthy normotensive pregnant women.
  
  
  METHODS
  A study was conducted including 29 uncomplicated women (the Control group) and 29 preeclamptic women (the Pre group). Preeclampsia was diagnosed by the increased blood pressure of >140mmHg systolic and >90mmHg diastolic in women who were normotensive before 20 weeks of gestation accompanied by proteinuria, defined as the urinary excretion of >0.3g protein in 24h specimen. Severe preeclampsia was defined as blood pressure >160/110mmHg on at least 2 occasions 6h apart with proteinuria >5g in a 24h urinary protein excretion. The maternal serum eNOS and ADMA concentrations were determined using a sandwich enzyme-linked immunosorbent assays.
  
  
  RESULTS
  There were no statistically significant differences in gravidity, parity, maternal age and height in patient profiles between groups. Creatinine and urea levels were normal in all patients. Systolic and diastolic blood pressures were higher in preeclamptic pregnant women than in the control group. The mean systolic blood pressure values were 166.39±15.47mmHg in the Pre group and 115.72±10.34mmHg in the control group. The mean diastolic blood pressure values were 108.89±10.45mmHg in the Pre group and 75.34±6.22mmHg in the healthy controls. These differences were statistically significant (p<0.000001). Our study revealed increased maternal serum levels of asymmetric dimethylarginine in preeclamptic patients (p=0.007223). The mean values of maternal serum ADMA were 0.597±0.161mmol/L in the Pre group versus0.503±0.081mmol/L in the healthy pregnant patients. The levels of serum endothelial nitric oxide synthase were lower in women with pregnancies complicated by severe preeclampsia than in the healthy women from the control group, but these differences were not statistically significant (p=0.118770). The mean values of serum eNOS were 134.06±76.73U/ml in the Pre group and 187.70±165.41U/ml in the Control group.
  
  
  CONCLUSIONS
  Elevated levels of ADMA and the unchanged levels of eNOS in pregnancies complicated by severe preeclampsia allow the conclusion that the nitric oxide deficiency in this pregnancy disorder result not from a reduced level or activity of eNOS, but from elevated levels of asymmetric dimethylarginine, an endogenous eNOS inhibitor.
authors.affiliation: Obstetrics and Perinatology, Medical University in Lublin, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Laskowska
authors.affiliation: Gastroenterology, University Hospital, Lublin, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Laskowska
authors.affiliation: Obstetrics and Perinatology, Medical University in Lublin, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Oleszczuk