Nitric oxide biosynthesis during normal pregnancy and pregnancy complicated by preeclampsia (original) (raw)
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Evaluation of Nitric Oxide Concentrations in Preeclampsia and Normal Pregnancy
Bangladesh Journal of Obstetrics & Gynaecology, 2020
During pregnancy Nitric oxide is one of the most important relaxing factors for myometrium and also in the control of blood flow in uterus and placenta. Nitric oxide is generated by endothelial type II nitric oxide synthase (NOS) and acts as a vasodilator. Objective:To investigate the level of nitric oxide (NO) production in pregnancies complicated by preeclampsia and in normal pregnancy. Materials and Methods: A case control study was undertaken in Department of Gynaecology and Obstetrics of Bangabandhu Sheikh Mujib Medical University (BSMMU), from january to july 2014. The study population was pregnant women having preeclampsia and normal pregnancy who attended the OPD Department of Obstetrics and Gynecology in BSMMU between 29 to 40 weeks of gestation. As because of transient and volatile nature of nitric oxide, it was unsuitable to measure the nitric oxide level by conventional method. However, two stable break down product, nitrate (NO3 -) and nitrate (NO2 -) could be easily de...
Estimation of Oxidative Products of Nitric Oxide (nitrates, nitrites) in Preeclampsia
Australian and New Zealand Journal of Obstetrics and Gynaecology, 1999
Summary: Oxidative products of nitric oxide, serum nitrates and nitrites were estimated in 50 primigravidas with preeclampsia and in 50 gestation and age‐matched normotensive primigravidas. Thirty three (66%) of these women had mild preeclampsia and 17 (34%) had severe preeclampsia. Serum nitrate and nitrite levels were significantly higher in preeclamptic women (nitrates—15± 1.17; nitrites—11.82± 1.16μmol/L) than in the normotensive pregnant women (nitrates 11.82± 1.16; nitrites—5.08± 0.47μmol/L, p < 0.001). In preeclamptic women, serum nitrate and nitrite levels correlated with the severity of the disease (mild preeclampsia nitrate—14.46± 1.98; nitrite 6.21± 0.84μmol/L, severe preeclampsia nitrate—16.65± 3.64; Nitrite—6.87± 1.56μmol/L). In preeclampsia there was significant positive correlation between nitrate and nitrite levels and diastolic blood pressure and proteinuria.
Nitric oxide in preeclampsia: lack of evidence for decreased production
European Journal of Obstetrics & Gynecology and Reproductive Biology, 1998
The purpose of our study was to determine the involvement of the L-arginine-NO system in preeclampsia. We studied 26 patients with preeclampsia and 27 normotensive pregnancies. Maternal and cord plasma, urine and amniotic fluid were assayed for nitric oxide metabolites (nitrite and nitrate) using the Griess reaction. Sections of placenta and fetal membranes were immunostained with polyclonal anti-endothelial and anti-neuronal nitric oxide synthase antibodies. The concentration of nitrate in the amniotic fluid of preeclamptic patients (median 10.3 mmol / mg creatinine) was significantly higher (P,0.001) than in the normotensive group (5.6 mmol / mg creatinine). Nitrate concentrations in maternal and cord plasma and in urine were similar in the two groups. Endothelial cells of the villi of preeclamptic placentas showed a higher positivity in endothelial nitric oxide synthase immunostaining with respect to normotensive controls. Our results indicate that feto-placental NO production is not reduced in preeclampsia. In contrast, the increased concentrations of NO metabolites in amniotic fluid and the positive immunostaining of endothelial nitric oxide synthase in the placental villi suggest that the placental L-arginine-NO system is up-regulated in preeclampsia.
Elevated levels of serum nitrate, a stable end product of nitric oxide, in women with pre-eclampsia
BJOG: An International Journal of Obstetrics and Gynaecology, 1997
Nitric oxide released from vascular endothelial cells is a potent vasodilator and inhibits platelet adhesion. It has been suggested that decreased nitric oxide production from dysfunctional endothelial cells is implicated in the pathophysiology of pre-eclampsia. In this study evidence was sought for abnormal production of nitric oxide in pre-eclamptic women. Blood was collected from 20 women presenting with pre-eclampsia, from 20 matched healthy pregnant controls and from 12 nonpregnant women of childbearing age. Serum nitrate, the stable end metabolite of nitric oxide, was measured by vanadium III chloride reduction and chemiluminescence. Sera from women with pre-eclampsia had significantly higher nitrate concentrations (mean 47.4 mumol/L [SD 13.6]) compared with healthy pregnant (mean 31.2 mumol/L [SD 9.14]) and nonpregnant (mean 32.1 mumol/L [SD 10.0]) controls. These results do not support the hypothesis that decreased endothelial cell nitric oxide production may be important in the pathophysiology of pre-eclampsia. On the contrary, serum nitrate levels are increased which may reflect either increased production of nitric oxide from an unidentified source or decreased elimination through the kidneys.
Maternal and Fetal Complications Due to Decreased Nitric Oxide Synthesis during Gestation
Complications of Pregnancy, 2019
Nitric oxide (NO) is synthesized from L-arginine by the constitutive NO synthase in vascular endothelial cells and plays an important role in the regulation of blood pressure and coronary vasomotion. Normal pregnancy is associated with major adaptations in maternal cardiovascular function, which help the woman to accommodate the growing fetus. The vascular endothelium is stimulated during pregnancy to release increased amounts of NO, and the abnormality in the L-arginine NO pathway may play a role in the etiology of preeclampsia. The objective of this study is to discuss the importance of nitric oxide during gestation and the maternal and fetal complications associated with decreased NO synthesis during this period. Maternal arterial hypertension due to inhibition of nitric oxide synthesis during pregnancy impairs fetal development, mainly the reduction of the wall/lumen ratio of the cardiac and renal microvasculature as well as the reduction in the number of nephrons. These changes...
Nitric oxide in different types of hypertension during pregnancy
Clinical science (London, England : 1979), 1997
1. Serum nitric oxide (NO) levels (determined by its products of oxidation) were assessed in non-pregnant women, normal pregnant women and patients suffering from mild pre-eclampsia (MPE), severe pre-eclampsia (SPE), chronic hypertension (CHT) and CHT with pre-eclampsia (CHT + PE). The levels of NO products were significantly reduced during pregnancy in MPE (P < 0.001), CHT + PE (P < 0.01) and SPE (P < 0.05). Significant reductions of NO products were also observed in puerperium (P < 0.001) in all groups except CHT + PE (P < 0.05). 2. In normal pregnancy, three events were related to NO levels: (1) negative correlations were found between the levels of nitrite (r = -0.73, P = 0.0003), nitrate (r = -0.53, P = 0.017) and the number of weeks of gestation; (2) in the caesarean section group, the levels of NO at puerperium were significantly lower (P < 0.05) than those during pregnancy; and (3) there was a significant reduction in NO levels in the pregnant women carryin...
Nitric oxide dysregulation in the pathogenesis of preeclampsia among Ghanaian women
Integrated Blood Pressure Control, 2015
Integrated Blood Pressure Control Dovepress submit your manuscript | www.dovepress.com Dovepress 1 O r I g I n a l r e s e a r C h open access to scientific and medical research Open access Full Text article http://dx.Background: Preeclampsia (PE) is still a disease of theories as the exact cause remains uncertain. Widespread vascular endothelial cell dysfunction is thought to mediate the generalized vasospasm and hypertension characteristic of PE. Altered nitric oxide (NO) production has been associated with the endothelial dysfunction in the pathogenesis of PE but conflicting results have emerged from previous studies. Objectives: To determine maternal serum levels of NO, a biomarker of endothelial function, in nonpregnant, normal pregnant, and preeclamptic women. Materials and methods: This was a cross-sectional case-control study of 277 women comprising 75 nonpregnant, 102 normal pregnant, and 100 preeclamptic women conducted at the Korle Bu Teaching Hospital between April and June 2011. About 5 mL of venous blood was obtained from the participants for the various investigations after meeting the inclusion criteria and signing to a written consent. Serum levels of NO were determined by Griess reaction. The data obtained were analyzed with SPSS version 20. Results: The study showed significantly elevated serum levels of NO in preeclamptic women (82.45±50.31 µM) compared with normal pregnant (33.12±17.81 µM) and nonpregnant (16.92±11.41 µM) women with P,0.001. The alteration in maternal serum NO levels was significantly more profound in early-onset (severe) PE (119.63±45.860 µM) compared to that of late-onset (mild) disease (62.44±40.44 µM) with P,0.001, indicating a more severe vascular endothelial cell dysfunction in the early-onset disease.
European Journal of Obstetrics & Gynecology and Reproductive Biology, 1999
Objectives: To measure maternal serum concentrations of total nitrites, as an index of nitric oxide synthesis, in normal and hypertensive pregnant women, and to examine the correlation between these concentrations and several variables of clinical interest. Study design: A total of 60 women in four different groups were studied: 10 normotensive pregnant women, 17 pregnant women with preeclampsia, 18 pregnant women with gestational hypertension and 15 pregnant women with chronic hypertension. Serum nitrite levels were determined using the Griess reaction after reduction with nitrate reductase. Results: Serum nitrite levels were higher in preeclamptic women (34.11614 mmol / l, P50.04), lower in chronic hypertensive women (19.5666.46 mmol / l, P50.04) and similar in women with gestational hypertension (26.9769.44 mmol / l) in comparison to the control group (25.3767.24 mmol / l). Serum nitrite levels in preeclamptic women had significant positive correlations with hematocrit, fasting insulinemia, and apolipoprotein B and negative correlations with platelet count, serum phosphorus and glucose:insulin ratio. In pregnant women with chronic hypertension a negative correlation was found between serum nitrite levels and active partial thromboplastin time. In pregnant women with gestational hypertension, serum nitrite levels had negative correlations with birthweight and 24-h urine calcium, and positive correlations with mean corspuscular hemoglobin, 24-h urine sodium and maternal age. Conclusions: We suggest that in women with preclampsia, a higher maternal nitric oxide level may act as a compensatory mechanism against hemoconcentration and platelet aggregation and that nitric oxide production may be related to some metabolic events. In women with gestational hypertension, higher serum nitrite levels may be related to clinical and biochemical findings common in preeclampsia. In chronic hypertension, a lower maternal nitric oxide level is related to the status of coagulation.