Maternal Nitric Oxide Levels Research Articles

Effect of l-Arginine on Nitric Oxide Levels in Intrauterine Growth Restriction and its Correlation with Fetal Outcome.

The current management of intrauterine growth restriction (IUGR) being empirical and aimed at selecting a safe time for delivery. Acknowledging the beneficial effects of l-arginine on endothelial vasculature the present study was designed to evaluate efficacy of l-arginine on bioavailability of nitric oxide (NO) with respect to fetal outcome. With l-arginine supplementation, mean NO levels were significantly increased and a significant mild reduction in systolic/end-diastolic velocity ratio (S/D ratio) was observed on doppler blood flow study, also neonatal outcome improved and incidences of complications were lowered. A deficiency in NO may play an important role in the causation of asymmetric fetal growth restriction. l-Arginine can be used to increase maternal NO levels, enhancing birth weight and decreasing neonatal morbidity. The ideal candidate for arginine therapy according to our study would be IUGR cases with S/D ratio less than 4.96±0.49 and NO levels below 33μmol/L with minimum of 3weeks duration of arginine supplementation.

Comparison of maternal serum and umbilical cord concentrations of nitric oxide and asymmetric-dimethyl-arginine in pre-eclamptic and uncomplicated pregnancies

The aim of this study was to compare maternal serum and umbilical cord levels of asymmetric-dimethyl-arginine (ADMA) and nitric oxide (NO) in pre-eclamptic and non-pre-eclamptic women and the possible effects of ADMA and NO on fetal outcome. Mean umbilical cord and maternal serum NO and ADMA levels of 29 women with preeclampsia (PE) and 24 randomly selected healthy pregnant women were compared. Maternal venous blood samples were collected before delivery and umbilical cord venous blood samples were obtained after delivery. Birth weight, apgar score, cord blood pH, duration of stay in the neonatal intensive care unit (NICU), and maternal and neonatal complications were recorded. Umbilical cord ADMA and maternal NO levels were significantly higher in women with pre-eclampsia compared to women without pre-eclampsia. There were no significant differences between means of maternal serum ADMA levels and cord blood NO levels in women with and without pre-eclampsia. Maternal and cord serum NO and ADMA levels in the pre-eclampsia group did not show a significant correlation with cord blood pH, umbilical artery pulsatility index (PI). In conclusion, umbilical cord ADMA and maternal NO levels were significantly higher in women with pre-eclampsia compared to women without pre-eclampsia.

Analysis of Nitric Oxide Metabolism as a Placental or Maternal Factor Underlying the Etiology of Pre-Eclampsia

Background:Defective nitric oxide (NO)-mediated vasodilation is widely regarded as an underlying cause of hypertension in pre-eclampsia, although there are also arguments against this hypothesis. Methods:We examined both the mRNA levels and the presence of a Glu298Asp substitution in the NO synthase (NOS) gene, as well as the NO metabolite concentration, in placentas and maternal sera from women with pre-eclampsia and in normotensive pregnant controls (25–40 vs. 24–41 weeks of gestation). Results:Pre-eclamptic and control placentas did not show any significant differences in their NO metabolite levels or their NOS expression levels as measured by quantitative RT-PCR. In addition, we did not find any association between pre-eclampsia and the occurrence of the Glu298Asp amino acid substitution in the NOS gene. In contrast, high maternal circulating NO metabolites were evident in severe pre-eclampsia (p < 0.0001). Although a positive correlation between circulating NO metabolites and blood pressure was not observed, uterine artery resistance measured by ultrasound was found to positively correlate with the maternal NO levels. Conclusions:Our current data suggest that an altered placental NOS pathway is unlikely to be the primary cause of pre-eclampsia and that the activation of this pathway is possibly in response to maternal symptoms.