Prophylactic treatment for preeclampsia in high-risk teenage primigravidae with nitric oxide donors: a pilot study

Evidence of Nitric Oxide Impairment During Hypertensive Pregnancies

Hypertensive disorders of pregnancy complicate up to 10% of pregnancies worldwide, and they can be classified into (1) gestational hypertension, (2) preeclampsia, (3) chronic hypertension and (4) chronic hypertension with preeclampsia. Nitric oxide (NO) plays an essential role in the haemodynamic adaptations observed during pregnancy. It has been shown that the nitric oxide pathway's dysfunction during pregnancy is associated with placental- and vascular-related diseases such as hypertensive disorders of pregnancy. This review aims to present a brief definition of hypertensive disorders of pregnancy and physiological maternal cardiovascular adaptations during pregnancy. We also detail how NO signalling is altered in the (a) systemic vasculature, (b) uterine artery/spiral arteries, (c) implantation and (d) placenta of hypertensive disorders during pregnancy. We conclude by summarizing the anti-hypertensive therapy of hypertensive disorders of pregnancy as a specific management strategy.

Decrease in Nitric Oxide Production as a Key Mediator in the Pathogenesis of Preeclampsia and a Potential Therapeutic Target: A Case-Control Study

Pregnancy-induced hypertension (GH) complicates 6−10% of all pregnancies and, in 2019, was responsible for approximately 28,000 deaths. The most common cause of gestational hypertension is pre-eclampsia (PE), which afflicts 2−8% of all pregnancies and is one of the three leading causes of maternal morbidity and mortality worldwide. The aim of this study was to clarify how NO metabolism changes during the course of PE. Due to the short half-life of NO, we measured the concentrations of its stable metabolites, nitrite and nitrate (NOx). Out of 100 enrolled patients: 58 pregnant women with a diagnosed early form of PE formed a study group, and 42 healthy pregnant women formed a control group. NOx concentrations were significantly lower in the PE group than in the control group, with mean values of 5.33 and 27.64 μmol/L, respectively (p < 0.0001). The decrease in NO is most likely the result and mediator of systemic endothelial dysfunction. The impairment of NO metabolism in PE appears to play an important role in its pathogenesis. Therefore, it is a potential therapeutic target.

The Role of Nitric Oxide, ADMA, and Homocysteine in The Etiopathogenesis of Preeclampsia-Review

Preeclampsia is a serious, pregnancy-specific, multi-organ disease process of compound aetiology. It affects 3–6% of expecting mothers worldwide and it persists as a leading cause of maternal and foetal morbidity and mortality. In fact, hallmark features of preeclampsia (PE) result from vessel involvement and demonstrate maternal endothelium as a target tissue. Growing evidence suggests that chronic placental hypoperfusion triggers the production and release of certain agents that are responsible for endothelial activation and injury. In this review, we will present the latest findings on the role of nitric oxide, asymmetric dimethylarginine (ADMA), and homocysteine in the etiopathogenesis of preeclampsia and their possible clinical implications.

Oxidative stress and endothelial function in normal pregnancy versus pre-eclampsia, a combined longitudinal and case control study

Background

Pre-eclampsia (PE) is related to an impaired endothelial function. Endothelial dysfunction accounts for altered vascular reactivity, activation of the coagulation cascade and loss of vascular integrity. Impaired endothelial function originates from production of inflammatory and cytotoxic factors by the ischemic placenta and results in systemic oxidative stress (OS) and an altered bioavailability of nitric oxide (•NO). The free radical •NO, is an endogenous endothelium-derived relaxing factor influencing endothelial function. In placental circulation, endothelial release of •NO dilates the fetal placental vascular bed, ensuring feto-maternal exchange. The Endopreg study was designed to evaluate in vivo endothelial function and to quantify in vitro OS in normal and pre-eclamptic pregnancies.

Methods/design

The study is divided into two arms, a prospective longitudinal study and a matched case control study. In the longitudinal study, pregnant patients ≥18 years old with a singleton pregnancy will be followed throughout pregnancy and until 6 months post-partum. In the case control study, cases with PE will be compared to matched normotensive pregnant women. Maternal blood concentration of superoxide (O₂•) and placental concentration of •NO will be determined using EPR (electron paramagnetic resonance). Endothelial function and arterial stiffness will be evaluated using respectively Peripheral Arterial Tonometry (PAT), Flow-Mediated Dilatation (FMD) and applanation tonometry. Placental expression of eNOS (endothelial NOS) will be determined using immune-histochemical staining. Target recruitment will be 110 patients for the longitudinal study and 90 patients in the case-control study.

Discussion

The results of Endopreg will provide longitudinal information on in vivo endothelial function and in vitro OS during normal pregnancy and PE. Adoption of these vascular tests in clinical practice potentially predicts patients at risk to develop cardiovascular events later in life after PE pregnancies. •NO, O₂•⁻ and eNOS measurements provide further inside in the pathophysiology of PE.

Trial registration

This trial has been registered on clinicaltrials.gov. ClinicalTrials.gov Identifier: NCT02603913. Registered October 2015.

[Can we prevent preeclampsia?]

Preeclampsia (PE), a specific complication of pregnancy, is one of the most frequent causes of maternal and fetal morbidity and mortality in the world. Recently, PE risk calculation algorithms allowing early detection of PE in the first trimester of pregnancy have been described. The aim of early detection would be to rapidly introduce an effective preventive treatment. The aim of our work is to study the different preventive treatments through the literature. Aspirin has some efficiency and reduces the risk of PE from 10 to 24%. It is most effective when the dose exceeds 75mg and when introduced before 16 gestational age. Early introduction of aspirin mainly prevents severe and preterm PE. Low molecular weight heparin (LMWH) and vitamin D appear to be promising therapy for PE but further research is required. Calcium administered at 1g/day reduces the risk of PE especially to patients with low baseline calcium intake. A low dose of calcium could also reduce the risk of PE but this must be confirmed. Other preventive measures (antioxidants, nitric oxide, progesterone, rest, exercise) do not reduce the incidence of PE.