Nitrotyrosine residues in placenta. Evidence of peroxynitrite formation and action

Bisphenol A and Its Emergent Substitutes: State of the Art of the Impact of These Plasticizers on Oxidative Stress and Its Role in Vascular Dysfunction

The "One Health approach" has evidenced the significant impact of xenobiotic exposure to health, and humans are a relevant target for their toxic effects. Bisphenol A (BPA) exerts a ubiquitous exposure source in all ecosystems. Given its endocrine-disrupting and harmful consequences on health, several countries have enforced new regulations to reduce exposure to BPA. Cardiovascular diseases (CVDs) are complex conditions that lead to higher mortality worldwide, where family history, lifestyle, and environmental factors, like BPA exposure, have a remarkable contribution. This chemical compound is the most widely used in plastic and epoxy resin manufacturing and has been associated with effects on human health. Therefore, new-generation bisphenols (NGBs) are replacing BPA use, arguing that they do not harm health. Nonetheless, the knowledge about whether NGBs are secure options is scanty. Although BPA's effects on several organs and systems have been documented, the role of BPA and NGBs in CVDs has yet to be explored. This review's goals are focused on the processes of endothelial activation (EA)-endothelial dysfunction (ED), a cornerstone of CVDs development, bisphenols' (BPs) effects on these processes through oxidant and antioxidant system alteration. Despite the scarce evidence on pro-oxidant effects associated with NGBs, our review demonstrated a comparable harmful effect on BPA. The results from the present review suggest that the biological mechanisms to explain BPs cardiotoxic effects are the oxidant stress ↔ inflammatory response ↔ EA ↔ ED → atherosclerotic plate → coagulation promotion. Other effects contributing to CVD development include altered lipid metabolism, ionic channels, and the activation of different intracellular pathways, which contribute to ED perpetuation in a concerted manner.

The Nitrate-Nitrite-Nitric Oxide Pathway: Potential Role in Mitigating Oxidative Stress in Hypertensive Disorders of Pregnancy

Hypertensive diseases of pregnancy (HDPs) represent a global clinical challenge, affecting 5-10% of women and leading to complications for both maternal well-being and fetal development. At the heart of these complications is endothelial dysfunction, with oxidative stress emerging as a pivotal causative factor. The reduction in nitric oxide (NO) bioavailability is a vital indicator of this dysfunction, culminating in blood pressure dysregulation. In the therapeutic context, although antihypertensive medications are commonly used, they come with inherent concerns related to maternal-fetal safety, and a percentage of women do not respond to these therapies. Therefore, alternative strategies that directly address the pathophysiology of HDPs are required. This article focuses on the potential of the nitrate-nitrite-NO pathway, abundantly present in dark leafy greens and beetroot, as an alternative approach to treating HDPs. The objective of this review is to discuss the prospective antioxidant role of nitrate. We hope our discussion paves the way for using nitrate to improve endothelial dysfunction and control oxidative stress, offering a potential therapy for managing HDPs.

BH4 supplementation reduces retinal cell death in ischaemic retinopathy

Dysregulation of nitric oxide (NO) production can cause ischaemic retinal injury and result in blindness. How this dysregulation occurs is poorly understood but thought to be due to an impairment in NO synthase function (NOS) and nitro-oxidative stress. Here we investigated the possibility of correcting this defective NOS activity by supplementation with the cofactor tetrahydrobiopterin, BH4. Retinal ischaemia was examined using the oxygen-induced retinopathy model and BH4 deficient Hph-1 mice used to establish the relationship between NOS activity and BH4. Mice were treated with the stable BH4 precursor sepiapterin at the onset of hypoxia and their retinas assessed 48 h later. HPLC analysis confirmed elevated BH4 levels in all sepiapterin supplemented groups and increased NOS activity. Sepiapterin treatment caused a significant decrease in neuronal cell death in the inner nuclear layer that was most notable in WT animals and was associated with significantly diminished superoxide and local peroxynitrite formation. Interestingly, sepiapterin also increased inflammatory cytokine levels but not microglia cell number. BH4 supplementation by sepiapterin improved both redox state and neuronal survival during retinal ischaemia, in spite of a paradoxical increase in inflammatory cytokines. This implicates nitro-oxidative stress in retinal neurones as the cytotoxic element in ischaemia, rather than enhanced pro-inflammatory signalling.

Review on new approach methods to gain insight into the feto-maternal interface physiology

Non-human animals represent a large and important feature in the history of biomedical research. The validity of their use, in terms of reproducible outcomes and translational confidence to the human situation, as well as ethical concerns surrounding that use, have been and remain controversial topics. Over the last 10 years, the communities developing microphysiological systems (MPS) have produced new approach method (NAMs) such as organoids and organs-on-a-chip. These alternative methodologies have shown indications of greater reliability and translatability than animal use in some areas, represent more humane substitutions for animals in these settings, and - with continued scientific effort - may change the conduct of basic research, clinical studies, safety testing, and drug development. Here, we present an introduction to these more human-relevant methodologies and suggest how a suite of pregnancy associated feto-maternal interface system-oriented NAMs may be integrated as reliable partial-/full animal replacements for investigators, significantly aid animal-/environmental welfare, and improve healthcare outcomes.

Maternal antioxidant micronutrient deficiencies among pre-eclamptic women in Enugu, Nigeria: a cross-sectional analytical study

OBJECTIVES

To determine the prevalence of antioxidant micronutrient deficiencies in pregnant women with pre-eclampsia and healthy pregnant women, and to assess the relationships between trace element deficiency in pregnancy and the severity of pre-eclampsia in Enugu, Nigeria.

METHODS

We performed a secondary analysis of a cross-sectional analytical study of serum concentrations of copper, selenium, zinc, magnesium, and manganese in 81 pregnant women with pre-eclampsia and healthy pregnant women (controls) who were matched for age, gestational age, body mass index, and parity. This study was performed at the University of Nigeria Teaching Hospital, Ituku-Ozalla, Enugu. Participants' sera were analyzed with an atomic absorption spectrophotometer.

RESULTS

Trace element deficiencies were common and similar between women with pre-eclampsia and controls. However, women with pre-eclampsia were more likely to be deficient in manganese than controls (odds ratio = 2.28, 95% confidence interval: 1.90-2.75). Among the micronutrients studied, only manganese concentrations were significantly lower in women without severe symptoms of pre-eclampsia than in those with severe symptoms of pre-eclampsia.

CONCLUSIONS

Micronutrient deficiency is common in pregnant women with pre-eclampsia and in healthy pregnant women in Enugu, Nigeria. Only manganese deficiency is higher in women with pre-eclampsia than in healthy pregnant women.

Oxidative Stress Markers in Human Brain and Placenta May Reveal the Timing of Hypoxic-Ischemic Injury: Evidence from an Immunohistochemical Study

During pregnancy, reactive oxygen species (ROS) serve as crucial signaling molecules for fetoplacental circulatory physiology. Oxidative stress is thought to sustain the pathogenesis and progression of hypoxic-ischemic encephalopathy (HIE). A retrospective study was performed on the brains and placentas of fetuses and newborns between 36-42 weeks of gestation (Group_1: Fetal intrauterine deaths, Group_2: Intrapartum deaths, Group_3: Post-partum deaths, Control group sudden neonatal death); all groups were further divided into two subgroups (Subgroup_B [brain] and Subgroup_P [placenta]), and the study was conducted through the immunohistochemical investigations of markers of oxidative stress (NOX2, 8-OHdG, NT, iNOS), IL-6, and only on the brain samples, AQP4. The results for the brain samples suggest that NOX2, 8-OHdG, NT, iNOS, and IL-6 were statistically significantly expressed above the controls. iNOS was more expressed in the fetal intrauterine death (Group_1) and less expressed in post-partum death (Group_3), while in intrapartum death (Group_2), the immunoreactivity was very low. IL-6 showed the highest expression in the brain cortex of the fetal intrauterine death (Group_1), while intrapartum death (Group_2) and post-partum death (Group_3) showed weak immunoreactivity. Post-partum death (Group_3) placentas showed the highest immunoreactivity to NOX2, which was almost double that of the fetal intrauterine death (Group_1) and intrapartum death (Group_2) placentas. Placental tissues of fetal intrauterine death (Group_1) and intrapartum death (Group_2) showed higher expression of iNOS than post-partum death (Group_3), while the IL-6 expression was higher in the fetal intrauterine death (Group_1) than the post-partum death (Group_3). The AQP4 was discarded as a possible marker because the immunohistochemical reaction in the three groups of cases and the control group was negative. The goal of this study, from the point of view of forensic pathology, is to provide scientific evidence in cases of medical liability in the Obstetric field to support the clinical data of the timing of HIE.

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.

Red Light Mitigates the Deteriorating Placental Extracellular Matrix in Late Onset of Preeclampsia and Improves the Trophoblast Behavior

Preeclampsia is a serious pregnancy disorder which in extreme cases may lead to maternal and fetal injury or death. Preexisting conditions which increase oxidative stress, e.g., hypertension and diabetes, increase the mother's risk to develop preeclampsia. Previously, we established that when the extracellular matrix is exposed to oxidative stress, trophoblast function is impaired, and this may lead to improper placentation. We investigated how the oxidative ECM present in preeclampsia alters the behavior of first trimester extravillous trophoblasts. We demonstrate elevated levels of advanced glycation end products (AGE) and lipid oxidation end product 4-hydroxynonenal in preeclamptic ECM (28%, and 32% increase vs control, respectively) accompanied with 35% and 82% more 3-chlorotyrosine and 3-nitrotyrosine vs control, respectively. Furthermore, we hypothesized that 670 nm phototherapy, which has antioxidant properties, reverses the observed trophoblast dysfunction as depicted in the improved migration and reduction in apoptosis. Since NO is critical for placentation, we examined eNOS activity in preeclamptic placentas compared to healthy ones and found no differences; however, 670 nm light treatment triggered enhanced NO availability presumably by using alternative NO sources. Light exposure decreased apoptosis and restored trophoblast migration to levels in trophoblasts cultured on preeclamptic ECM. Moreover, 670 nm irradiation restored expression of Transforming Growth Factor (TGFβ) and Placental Growth Factor (PLGF) to levels observed in trophoblasts cultured on healthy placental ECM. We conclude the application of 670 nm light can successfully mitigate the damaged placental microenvironment of late onset preeclampsia as depicted by the restored trophoblast behavior.

Endothelial dysfunction in preterm infants: The hidden legacy of uteroplacental pathologies

Millions of infants are born prematurely every year worldwide. Prematurity, particularly at lower gestational ages, is associated with high mortality and morbidity and is a significant global health burden. Pregnancy complications and preterm birth syndrome strongly impact neonatal clinical phenotypes and outcomes. The vascular endothelium is a pivotal regulator of fetal growth and development. In recent years, the key role of uteroplacental pathologies impairing endothelial homeostasis is emerging. Conditions leading to very and extremely preterm birth can be classified into two main pathophysiological patterns or endotypes: infection/inflammation and dysfunctional placentation. The first is frequently related to chorioamnionitis, whereas the second is commonly associated with hypertensive disorders of pregnancy and fetal growth restriction. The nature, timing, and extent of prenatal noxa may alter fetal and neonatal endothelial phenotype and functions. Changes in the luminal surface, oxidative stress, growth factors imbalance, and dysregulation of permeability and vascular tone are the leading causes of endothelial dysfunction in preterm infants. However, the available evidence regarding endothelial physiology and damage is limited in neonates compared to adults. Herein, we discuss the current knowledge on endothelial dysfunction in the infectious/inflammatory and dysfunctional placentation endotypes of prematurity, summarizing their molecular features, available biomarkers, and clinical impact. Furthermore, knowledge gaps, shadows, and future research perspectives are highlighted.

Preeclampsia and Cardiovascular Risk for Offspring

There is growing evidence of long-term cardiovascular sequelae in children after in utero exposure to preeclampsia. Maternal hypertension and/or placental ischaemia during pregnancy increase the risk of hypertension, stroke, diabetes, and cardiovascular disease (CVD) in the offspring later in life. The mechanisms associated with CVD seem to be a combination of genetic, molecular, and environmental factors which can be defined as fetal and postnatal programming. The aim of this paper is to discuss the relationship between pregnancy complicated by preeclampsia and possibility of CVD in the offspring. Unfortunately, due to its multifactorial nature, a clear dependency mechanism between preeclampsia and CVD is difficult to establish.

Role of oxidative stress in the dysfunction of the placental endothelial nitric oxide synthase in preeclampsia

Preeclampsia (PE) is a multifactorial pregnancy disease, characterized by new-onset gestational hypertension with (or without) proteinuria or end-organ failure, exclusively observed in humans. It is a leading cause of maternal morbidity affecting 3–7% of pregnant women worldwide. PE pathophysiology could result from abnormal placentation due to a defective trophoblastic invasion and an impaired remodeling of uterine spiral arteries, leading to a poor adaptation of utero-placental circulation. This would be associated with hypoxia/reoxygenation phenomena, oxygen gradient fluctuations, altered antioxidant capacity, oxidative stress, and reduced nitric oxide (NO) bioavailability. This results in part from the reaction of NO with the radical anion superoxide (O₂^•−), which produces peroxynitrite ONOO^-, a powerful pro-oxidant and inflammatory agent. Another mechanism is the progressive inhibition of the placental endothelial nitric oxide synthase (eNOS) by oxidative stress, which results in eNOS uncoupling via several events such as a depletion of the eNOS substrate L-arginine due to increased arginase activity, an oxidation of the eNOS cofactor tetrahydrobiopterin (BH4), or eNOS post-translational modifications (for instance by S-glutathionylation). The uncoupling of eNOS triggers a switch of its activity from a NO-producing enzyme to a NADPH oxidase-like system generating O₂^•−, thereby potentiating ROS production and oxidative stress. Moreover, in PE placentas, eNOS could be post-translationally modified by lipid peroxidation-derived aldehydes such as 4-oxononenal (ONE) a highly bioreactive agent, able to inhibit eNOS activity and NO production. This review summarizes the dysfunction of placental eNOS evoked by oxidative stress and lipid peroxidation products, and the potential consequences on PE pathogenesis.

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Physiological ROS production is enhanced during pregnancy.

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eNOS is one of the main target of oxidative stress in PE placenta.

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eNOS is S-glutathionylated in PE placentas.

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eNOS is modified by lipid oxidation products in PE placentas.

Placental Adaptive Changes to Protect Function and Decrease Oxidative Damage in Metabolically Healthy Maternal Obesity

Pregnancy-related disorders, including preeclampsia and gestational diabetes, are characterized by the presence of an adverse intrauterine milieu that may ultimately result in oxidative and nitrosative stress. This scenario may trigger uncontrolled production of reactive oxygen species (ROS) such as superoxide anion (O^●−) and reactive nitrogen species (RNS) such as nitric oxide (NO), along with an inactivation of antioxidant systems, which are associated with the occurrence of relevant changes in placental function through recognized redox post-translational modifications in key proteins. The general objective of this study was to assess the impact of a maternal obesogenic enviroment on the regulation of the placental nitroso-redox balance at the end of pregnancy. We measured oxidative damage markers—thiobarbituric acid-reacting substances (TBARS) and carbonyl groups (C=O) levels; nitrosative stress markers—inducible nitric oxide synthase, nitrosothiol groups, and nitrotyrosine residues levels; and the antioxidant biomarkers—catalase and superoxide dismutase (SOD) activity and expression, and total antioxidant capacity (TAC), in full-term placental villous from both pre-pregnancy normal weight and obese women, and with absence of metabolic complications throughout gestation. The results showed a decrease in C=O and TBARS levels in obese pregnancies. Although total SOD and catalase concentrations were shown to be increased, both activities were significantly downregulated in obese pregnancies, along with total antioxidant capacity. Inducible nitric oxide sintase levels were increased in the obese group compared to the lean group, accompanied by an increase in nitrotyrosine residues levels and lower levels of nitrosothiol groups in proteins such as ERK1/2. These findings reveal a reduction in oxidative damage, accompanied by a decline in antioxidant response, and an increase via NO-mediated nitrative stress in placental tissue from metabolically healthy pregnancies with obesity. All this plausibly points to a placental adaptation of the affected antioxidant response towards a NO-induced alternative pathway, through changes in the ROS/RNS balance, in order to reduce oxidative damage and preserve placental function in pregnancy.

Nitric oxide metabolism in the human placenta during aberrant maternal inflammation

KEY POINTS

Nitric oxide (NO) is a gasotransmitter with important physiological and pathophysiological roles in pregnancy. There is limited information available about the sources and metabolism of NO and its bioactive metabolites (NOx) in both normal and complicated pregnancies. The present study characterized and quantified endogenous NOx in human and mouse placenta following determination of the stability of exogenous NOx in placental homogenates. NOx have differential stability in placental homogenates. NO and iron nitrosyl species (FeNOs), are relatively unstable in placental homogenates from normal placentas. Exogenous NO, nitrite and nitrosothiols react with placental homogenates to form iron nitrosyl complexes. FeNOs were also detected endogenously in mouse and human placenta. NOx levels in placental villous tissue are increased in fetal growth restriction vs. placentas from women with normal pregnancies, particularly in fetal growth restriction associated with pre-eclampsia. Villitis was not associated, however, with an increase in NOx levels in either normotensive or pre-eclamptic placentas. The results call for further investigation of FeNOs in normal and complicated pregnancies.

ABSTRACT

Nitric oxide (NO) is a gasotransmitter with important roles in pregnancy under both physiological and pathophysiological conditions. Although products of NO metabolism (NOx) also have significant bioactivity, little is known about the role of NO and NOx under conditions of aberrant placental inflammation during pregnancy. An ozone-based chemiluminescence approach was used to investigate the stability and metabolic fate of NOx in human placental homogenates from uncomplicated pregnancies in healthy mothers compared to that in placental tissue from normotensive and pre-eclamptic pregnancies complicated with fetal growth restriction (FGR) with and without villitis of unknown aetiology. We hypothesized that placental NOx would be increased in FGR vs. normal tissue, and be further increased in villitis vs. non-villitis placentas. Findings indicate that nitrate, nitrite and nitrosothiols, but not NO or iron nitrosyl species (FeNOs), are relatively stable in placental homogenates from normal placentas, and that NO, nitrite and nitrosothiols react with placental homogenates to form iron nitrosyl complexes. Furthermore, NOx levels in placental villous tissue are increased in FGR vs. placentas from women with normal pregnancies, particularly in FGR associated with pre-eclampsia. However, in contrast to our hypothesis, villitis was not associated with an increase in NOx levels in either normotensive or pre-eclamptic placentas. Our results also strongly support the involvement of FeNOs in both mouse and human placenta, and call for their further study as a critical mechanistic link between pre-eclampsia and fetal growth restriction.

Mechanisms linking exposure to preeclampsia in utero and the risk for cardiovascular disease

Preeclampsia (PE) is now recognised as a cardiovascular risk factor for women. Emerging evidence suggests that children exposed to PE in utero may also be at increased risk of cardiovascular disease (CVD) in later life. Individuals exposed to PE in utero have higher systolic and diastolic blood pressure and higher body mass index (BMI) compared to those not exposed to PE in utero. The aim of this review is to discuss the potential mechanisms driving the relationship between PE and offspring CVD. Exposure to an adverse intrauterine environment as a consequence of the pathophysiological changes that occur during a pregnancy complicated by PE is proposed as one mechanism that programs the fetus for future CVD risk. Consistent with this hypothesis, animal models of PE where progeny have been studied demonstrate causality for programming of offspring cardiovascular health by the preeclamptic environment. Shared alleles between mother and offspring, and shared lifestyle factors between mother and offspring provide alternate pathways explaining associations between PE and offspring CVD risk. In addition, adverse lifestyle habits can also act as second hits for those programmed for increased CVD risk. PE and CVD are both multifactorial diseases and, hence, identifying the relative contribution of PE to offspring risk for CVD is a very complex task. However, considering the emerging strong association between PE and CVD, those exposed to PE in utero may benefit from targeted primary CVD preventive strategies.

Maternal disease and gasotransmitters

The three known gasotransmitters, nitric oxide, carbon monoxide, and hydrogen sulfide are involved in key processes throughout pregnancy. Gasotransmitters are known to impact on smooth muscle tone, regulation of immune responses, and oxidative state of cells and their component molecules. Failure of the systems that tightly regulate gasotransmitter production and downstream effects are thought to contribute to common maternal diseases such as preeclampsia and preterm birth. Normal pregnancy-related changes in uterine blood flow depend heavily on gasotransmitter signaling. In preeclampsia, endothelial dysfunction is a major contributor to aberrant gasotransmitter signaling, resulting in hypertension after 20 weeks gestation. Maintenance of pregnancy to term also requires gasotransmitter-mediated uterine quiescence. As the appropriate signals for parturition occur, regulation of gasotransmitter signaling must work in concert with those endocrine signals in order for appropriate labor and delivery timing. Like preeclampsia, preterm birth may have origins in abnormal gasotransmitter signaling. We review the evidence for the involvement of gasotransmitters in preeclampsia and preterm birth, as well as mechanistic and molecular signaling targets.

Study on the Effect of Severity of Maternal Iron Deficiency Anemia on Regulators of Angiogenesis in Placenta

Aims: In this study, we hypothesized that maternal anemia leads to altered expression of angiogenic proteins vascular endothelial growth factor (VEGF), placental growth factor (PLGF), nitrotyrosine (NT) residues, and endothelial nitric oxide synthase (e-NOS) in the placenta. Hence, we study the expression of the abovementioned proteins in the placentas of mothers with different grades of anemia. Materials and methods: Our study was conducted in 48 pregnant women (36-40 weeks of gestation), who were divided into four groups-normal, mild, moderate, and severe anemia. After delivery, the expression of the angiogenic proteins was studied in their placentas by immunohistochemistry. Results: In our study, 58.3% of the pregnant women were anemic, among which 20.83% had mild anemia, 18.75% had moderate anemia, and 18.75% had severe anemia. Immunohistochemical staining intensity for VEGF, PLGF, NT residues, and e-NOS proteins was observed to be higher in the placentas of anemic women when compared with the non-anemic women. Conclusion: Our study showed that there is an increased expression of angiogenic proteins in the placentas of anemic mothers, which probably is an adaptive response leading to changes in placental vessels.

Alpha-1 microglobulin as a potential therapeutic candidate for treatment of hypertension and oxidative stress in the STOX1 preeclampsia mouse model

Preeclampsia is a human placental disorder affecting 2–8% of pregnancies worldwide annually, with hypertension and proteinuria appearing after 20 weeks of gestation. The underlying cause is believed to be incomplete trophoblast invasion of the maternal spiral arteries during placentation in the first trimester, resulting in oxidative and nitrative stress as well as maternal inflammation and organ alterations. In the Storkhead box 1 (STOX1) preeclampsia mouse model, pregnant females develop severe and early onset manifestations as seen in human preeclampsia e.g. gestational hypertension, proteinuria, and organ alterations. Here we aimed to evaluate the therapeutic potential of human recombinant alpha-1 microglobulin (rA1M) to alleviate the manifestations observed. Human rA1M significantly reduced the hypertension during gestation and significantly reduced the level of hypoxia and nitrative stress in the placenta. In addition, rA1M treatment reduced cellular damage in both placenta and kidneys, thereby protecting the tissue and improving their function. This study confirms that rA1M has the potential as a therapeutic drug in preeclampsia, and likely also in other pathological conditions associated with oxidative stress, by preserving normal organ function.

Effect of Oxidative Stress on the Estrogen-NOS-NO-KCa Channel Pathway in Uteroplacental Dysfunction: Its Implication in Pregnancy Complications

During pregnancy, the adaptive changes in uterine circulation and the formation of the placenta are essential for the growth of the fetus and the well-being of the mother. The steroid hormone estrogen plays a pivotal role in this adaptive process. An insufficient blood supply to the placenta due to uteroplacental dysfunction has been associated with pregnancy complications including preeclampsia and intrauterine fetal growth restriction (IUGR). Oxidative stress is caused by an imbalance between free radical formation and antioxidant defense. Pregnancy itself presents a mild oxidative stress, which is exaggerated in pregnancy complications. Increasing evidence indicates that oxidative stress plays an important role in the maladaptation of uteroplacental circulation partly by impairing estrogen signaling pathways. This review is aimed at providing both an overview of our current understanding of regulation of the estrogen-NOS-NO-K_Ca pathway by reactive oxygen species (ROS) in uteroplacental tissues and a link between oxidative stress and uteroplacental dysfunction in pregnancy complications. A better understanding of the mechanisms will facilitate the development of novel and effective therapeutic interventions.

Sexual dimorphism of mitochondrial function in the hypoxic guinea pig placenta

Placental hypoxia can stimulate oxidative stress and mitochondrial dysfunction reducing placental efficiency and inducing fetal growth restriction (FGR). We hypothesized that chronic hypoxia inhibits mitochondrial function in the placenta as an underlying cause of cellular mechanisms contributing to FGR. Pregnant guinea pigs were exposed to either normoxia (NMX) or hypoxia (HPX; 10.5% O2) at 25 day gestation until term (65 day). Guinea pigs were anesthetized, and fetuses and placentas were excised at either mid (40 day) or late gestation (64 day), weighed, and placental tissue stored at -80°C until assayed. Mitochondrial DNA content, protein expression of respiratory Complexes I-V, and nitration and activity rates of Complexes I and IV were measured in NMX and HPX male (N = 6 in each treatment) and female (N = 6 in each treatment) placentas. Mitochondrial density was not altered by HPX in either mid- or late-term placentas. In mid gestation, HPX slightly increased expression of Complexes I-III and V in male placentas only, but had no effect on either Complex I or IV activity rates or nitrotyrosine expression. In late gestation, HPX significantly decreased CI/CIV activity rates and increased CI/CIV nitration in male but not female placentas exhibiting a sexual dimorphism. Complex I-V expression was reduced from mid to late gestation in both male and female placentas regardless of treatment. We conclude that chronic HPX decreases mitochondrial function by inhibiting Complex I/IV activity via increased peroxynitrite in a sex-related manner. Further, there may be a progressive decrease in energy metabolism of placental cell types with gestation that increases the vulnerability of placental function to intrauterine stress.

Mechanisms of Dysfunction in the Aging Vasculature and Role in Age-Related Disease

Advancing age promotes cardiovascular disease (CVD), the leading cause of death in the United States and many developed nations. Two major age-related arterial phenotypes, large elastic artery stiffening and endothelial dysfunction, are independent predictors of future CVD diagnosis and likely are responsible for the development of CVD in older adults. Not limited to traditional CVD, these age-related changes in the vasculature also contribute to other age-related diseases that influence mammalian health span and potential life span. This review explores mechanisms that influence age-related large elastic artery stiffening and endothelial dysfunction at the tissue level via inflammation and oxidative stress and at the cellular level via Klotho and energy-sensing pathways (AMPK [AMP-activated protein kinase], SIRT [sirtuins], and mTOR [mammalian target of rapamycin]). We also discuss how long-term calorie restriction-a health span- and life span-extending intervention-can prevent many of these age-related vascular phenotypes through the prevention of deleterious alterations in these mechanisms. Lastly, we discuss emerging novel mechanisms of vascular aging, including senescence and genomic instability within cells of the vasculature. As the population of older adults steadily expands, elucidating the cellular and molecular mechanisms of vascular dysfunction with age is critical to better direct appropriate and measured strategies that use pharmacological and lifestyle interventions to reduce risk of CVD within this population.

Identification of the functional pathways altered by placental cell exposure to high glucose: lessons from the transcript and metabolite interactome

The specific consequences of hyperglycaemia on placental metabolism and function are incompletely understood but likely contribute to poor pregnancy outcomes associated with diabetes mellitus (DM). This study aimed to identify the functional biochemical pathways perturbed by placental exposure to high glucose levels through integrative analysis of the trophoblast transcriptome and metabolome. The human trophoblast cell line, BeWo, was cultured in 5 or 25 mM glucose, as a model of the placenta in DM. Transcriptomic analysis using microarrays, demonstrated 5632 differentially expressed gene transcripts (≥± 1.3 fold change (FC)) following exposure to high glucose. These genes were used to generate interactome models of transcript response using BioGRID (non-inferred network: 2500 nodes (genes) and 10541 protein-protein interactions). Ultra performance-liquid chromatography-mass spectrometry (MS) and gas chromatography-MS analysis of intracellular extracts and culture medium were used to assess the response of metabolite profiles to high glucose concentration. The interactions of altered genes and metabolites were assessed using the MetScape interactome database, resulting in an integrated model of systemic transcriptome (2969 genes) and metabolome (41 metabolites) response within placental cells exposed to high glucose. The functional pathways which demonstrated significant change in response to high glucose included fatty acid β-oxidation, phospholipid metabolism and phosphatidylinositol phosphate signalling.

N-Acetylcysteine, a glutathione precursor, reverts vascular dysfunction and endothelial epigenetic programming in intrauterine growth restricted guinea pigs

KEY POINTS

Intrauterine growth restriction (IUGR) is associated with vascular dysfunction, oxidative stress and signs of endothelial epigenetic programming of the umbilical vessels. There is no evidence that this epigenetic programming is occurring on systemic fetal arteries. In IUGR guinea pigs we studied the functional and epigenetic programming of endothelial nitric oxide synthase (eNOS) (Nos3 gene) in umbilical and systemic fetal arteries, addressing the role of oxidative stress in this process by maternal treatment with N-acetylcysteine (NAC) during the second half of gestation. The present study suggests that IUGR endothelial cells have common molecular markers of programming in umbilical and systemic arteries. Notably, maternal treatment with NAC restores fetal growth by increasing placental efficiency and reverting the functional and epigenetic programming of eNOS in arterial endothelium in IUGR guinea pigs.

ABSTRACT

In humans, intrauterine growth restriction (IUGR) is associated with vascular dysfunction, oxidative stress and signs of endothelial programming in umbilical vessels. We aimed to determine the effects of maternal antioxidant treatment with N-acetylcysteine (NAC) on fetal endothelial function and endothelial nitric oxide synthase (eNOS) programming in IUGR guinea pigs. IUGR was induced by implanting ameroid constrictors on uterine arteries of pregnant guinea pigs at mid gestation, half of the sows receiving NAC in the drinking water (from day 34 until term). Fetal biometry and placental vascular resistance were followed by ultrasound throughout gestation. At term, umbilical arteries and fetal aortae were isolated to assess endothelial function by wire-myography. Primary cultures of endothelial cells (ECs) from fetal aorta, femoral and umbilical arteries were used to determine eNOS mRNA levels by quantitative PCR and analyse DNA methylation in the Nos3 promoter by pyrosequencing. Doppler ultrasound measurements showed that NAC reduced placental vascular resistance in IUGR (P < 0.05) and recovered fetal weight (P < 0.05), increasing fetal-to-placental ratio at term (∼40%) (P < 0.001). In IUGR, NAC treatment restored eNOS-dependent relaxation in aorta and umbilical arteries (P < 0.05), normalizing eNOS mRNA levels in EC fetal and umbilical arteries (P < 0.05). IUGR-derived ECs had a decreased DNA methylation (∼30%) at CpG -170 (from the transcription start site) and this epigenetic signature was absent in NAC-treated fetuses (P < 0.001). These data show that IUGR-ECs have common molecular markers of eNOS programming in umbilical and systemic arteries and this effect is prevented by maternal treatment with antioxidants.

Role of l-Arginine in Oligohydramnios

BACKGROUND

Oligohydramnios is a known obstetric complication which is associated with operative interferences and perinatal morbidity and mortality. l-arginine is a precursor of nitric oxide and may play a role in local vasodilatation. Administration of l-arginine has been suggested to improve amniotic fluid index (AFI) in oligohydramnios.

AIMS AND OBJECTIVES

To study the effect of l-arginine in optimizing fetal outcome in cases of oligohydramnios.

MATERIALS AND METHODS

A retrospective study was conducted at Dr L H Hiranandani hospital consisting of 100 antenatal patients diagnosed with oligohydramnios [AFI < 8 cm] remote from term. Patients were evaluated for all antenatal risk factors and were started on l-arginine sachets (3 g, 3 sachets a day). The treatment was continued till an adequate improvement in liquor was noted. However, patients were considered for delivery if the liquor remained <5. Further, mean increase in AFI, intervention delivery interval, and neonatal outcome were studied.

RESULTS

The mean gestational age at the time of recruitment was 32.3 weeks. The mean AFI noted was 5.421 cm. These patients were delivered at 35 ± 1.1 weeks, and thus, pregnancy could be prolonged by 2.4 ± 1.1 weeks. The mean AFI at the end of therapeutic intervention was 8.753, and thus, an AFI increase of 3.332 cm could be obtained. There was no significant neonatal morbidity in these patients. Significant improvement in liquor volume was obtained in these patients after intervention with l-arginine sachets.

CONCLUSION

l-arginine supplementation is promising in improving volume of amniotic fluid in cases of oligohydramnios and prolonging pregnancy by a mean of 2.4 weeks, allowing fetal lung maturation thus benefiting the neonatal outcome.

Oxidative stress damage-associated molecular signaling pathways differentiate spontaneous preterm birth and preterm premature rupture of the membranes

STUDY HYPOTHESIS

In women with preterm premature rupture of the membranes (PPROM), increased oxidative stress may accelerate premature cellular senescence, senescence-associated inflammation and proteolysis, which may predispose them to rupture.

STUDY FINDING

We demonstrate mechanistic differences between preterm birth (PTB) and PPROM by revealing differences in fetal membrane redox status, oxidative stress-induced damage, distinct signaling pathways and senescence activation.

WHAT IS KNOWN ALREADY

Oxidative stress-associated fetal membrane damage and cell cycle arrest determine adverse pregnancy outcomes, such as spontaneous PTB and PPROM.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

Fetal membranes and amniotic fluid samples were collected from women with PTB and PPROM. Molecular, biochemical and histologic markers were used to document differences in oxidative stress and antioxidant enzyme status, DNA damage, secondary signaling activation by Ras-GTPase and mitogen-activated protein kinases, and activation of senescence between membranes from the two groups.

MAIN RESULTS AND THE ROLE OF CHANCE

Oxidative stress was higher and antioxidant enzymes were lower in PPROM compared with PTB. PTB membranes had minimal DNA damage and showed activation of Ras-GTPase and ERK/JNK signaling pathway with minimal signs of senescence. PPROM had higher numbers of cells with DNA damage, prosenescence stress kinase (p38 MAPK) activation and signs of senescence.

LIMITATIONS, REASONS FOR CAUTION

Samples were obtained retrospectively after delivery. The markers of senescence that we tested are specific but are not sufficient to confirm senescence as the pathology in PPROM.

WIDER IMPLICATIONS OF THE FINDINGS

Oxidative stress-induced DNA damage and senescence are characteristics of fetal membranes from PPROM, compared with PTB with intact membranes. PTB and PPROM arise from distinct pathophysiologic pathways. Oxidative stress and oxidative stress-induced cellular damages are likely determinants of the mechanistic signaling pathways and phenotypic outcome.

STUDY FUNDING AND COMPETING INTERESTS

This study is supported by developmental funds to Dr R. Menon from the Department of Obstetrics and Gynecology at The University of Texas Medical Branch at Galveston and funds to Dr M. Kacerovský from the Ministry of Health Czech Republic (UHHK, 001799906). The authors report no conflict of interest.

Intrauterine trophoblast migration: A comparative view of humans and rodents

Trophoblast migration and invasion through the decidua and maternal uterine spiral arteries are crucial events in placentation. During this process, invasive trophoblast replace vascular endothelial cells as the uterine arteries are remodeled to form more permissive vessels that facilitate adequate blood flow to the growing fetus. Placentation failures resulting from either extensive or shallow trophoblastic invasion can cause pregnancy complications such as preeclampsia, intrauterine growth restriction, placenta creta, gestational trophoblastic disease and even maternal or fetal death. Consequently, the use of experimental animal models such as rats and mice has led to great progress in recent years with regards to the identification of mechanisms and factors that control trophoblast migration kinetics. This review aims to perform a comparative analysis of placentation and the mechanisms and factors that coordinate intrauterine trophoblast migration in humans, rats and mice under physiological and pathological conditions.

Presence of Telocytes in a Non-innervated Organ: The Placenta

This chapter discusses the relationship between failure in placentation and the subsequent alterations in the normal structure of the placenta. Interstitial Cajal-like cells (ICLC) were observed for the first time in the human placenta in 2007 and later were named telocytes. Strong evidence confirms that in the placental chorionic villi, TC are located strategically between the smooth muscle cells (SMC) of the fetal blood vessel wall and the stromal myofibroblasts. As the placenta is a non-innervated organ and considering the strategic position of telocytes in chorionic villi, it has been postulated that their function would be related to signal transduction mechanisms involved in the regulation of the blood flow in the fetal vessels, as well as in the shortening/lengthening of the chorionic villi providing the necessary rhythmicity to the process of maternal/fetal metabolic exchange. In this context, telocytes represent part of a functional triad: "SMC of fetal blood vessel-telocyte-myofibroblast." This triad takes part in the regulation of fetal growth and development via transport of nutrients and gases. This chapter also discusses the alterations in the metabolic maternal-fetal exchange, leading to intrauterine growth retardation and preeclampsia. Additionally, the apoptosis undergoing in the preeclamptic hypoxic placenta affects all the chorionic villi cells, including telocytes and myofibroblast, and not only trophoblast, as it has been so far considered. In consequence, we proposed that apoptosis affects the triad structure and alters the placental function, subsequently affecting the normal fetal growth and development.

Evidence-Based Revised View of the Pathophysiology of Preeclampsia

Preeclampsia is a life-threatening vascular disorder of pregnancy due to a failing stressed placenta. Millions of women risk death to give birth each year and globally each year, almost 300,000 lose their life in this process and over 500,000 babies die as a consequence of preeclampsia. Despite decades of research, we lack pharmacological agents to treat it. Maternal endothelial oxidative stress is a central phenomenon responsible for the preeclampsia phenotype of high maternal blood pressure and proteinuria. In 1997, it was proposed that preeclampsia arises due to the loss of VEGF activity, possibly due to elevation in anti-angiogenic factor, soluble Flt-1 (sFlt-1). Researchers showed that high sFlt-1 and soluble endoglin (sEng) elicit the severe preeclampsia phenotype in pregnant rodents. We demonstrated that heme oxygenase-1 (HO-1)/carbon monoxide (CO) pathway prevents placental stress and suppresses sFlt-1 and sEng release. Likewise, hydrogen sulphide (H₂S)/cystathionine-γ-lyase (Cth) systems limit sFlt-1 and sEng and protect against the preeclampsia phenotype in mice. Importantly, H₂S restores placental vasculature, and in doing so improves lagging fetal growth. These molecules act as the inhibitor systems in pregnancy and when they fail, preeclampsia is triggered. In this review, we discuss what are the hypotheses and models for the pathophysiology of preeclampsia on the basis of Bradford Hill causation criteria for disease causation and how further in vivo experimentation is needed to establish 'proof of principle'. Hypotheses that fail to meet the Bradford Hill causation criteria include abnormal spiral artery remodelling and inflammation and should be considered associated or consequential to the disorder. In contrast, the protection against cellular stress hypothesis that states that the protective pathways mitigate cellular stress by limiting elevation of anti-angiogenic factors or oxidative stress and the subsequent clinical signs of preeclampsia appear to fulfil most of Bradford Hill causation criteria. Identifying the candidates on the roadmap to this pathway is essential in developing diagnostics and therapeutics to target the pathogenesis of preeclampsia.

Cellular and molecular biology of aging endothelial cells

Cardiovascular disease (CVD) is the leading cause of death in the United States and aging is a major risk factor for CVD development. One of the major age-related arterial phenotypes thought to be responsible for the development of CVD in older adults is endothelial dysfunction. Endothelial function is modulated by traditional CVD risk factors in young adults, but advancing age is independently associated with the development of vascular endothelial dysfunction. This endothelial dysfunction results from a reduction in nitric oxide bioavailability downstream of endothelial oxidative stress and inflammation that can be further modulated by traditional CVD risk factors in older adults. Greater endothelial oxidative stress with aging is a result of augmented production from the intracellular enzymes NADPH oxidase and uncoupled eNOS, as well as from mitochondrial respiration in the absence of appropriate increases in antioxidant defenses as regulated by relevant transcription factors, such as FOXO. Interestingly, it appears that NFkB, a critical inflammatory transcription factor, is sensitive to this age-related endothelial redox change and its activation induces transcription of pro-inflammatory cytokines that can further suppress endothelial function, thus creating a vicious feed-forward cycle. This review will discuss the two macro-mechanistic processes, oxidative stress and inflammation, that contribute to endothelial dysfunction with advancing age as well as the cellular and molecular events that lead to the vicious cycle of inflammation and oxidative stress in the aged endothelium. Other potential mediators of this pro-inflammatory endothelial phenotype are increases in immune or senescent cells in the vasculature. Of note, genomic instability, telomere dysfunction or DNA damage has been shown to trigger cell senescence via the p53/p21 pathway and result in increased inflammatory signaling in arteries from older adults. This review will discuss the current state of knowledge regarding the emerging concepts of senescence and genomic instability as mechanisms underlying oxidative stress and inflammation in the aged endothelium. Lastly, energy sensitive/stress resistance pathways (SIRT-1, AMPK, mTOR) are altered in endothelial cells and/or arteries with aging and these pathways may modulate endothelial function via key oxidative stress and inflammation-related transcription factors. This review will also discuss what is known about the role of "energy sensing" longevity pathways in modulating endothelial function with advancing age. With the growing population of older adults, elucidating the cellular and molecular mechanisms of endothelial dysfunction with age is critical to establishing appropriate and measured strategies to utilize pharmacological and lifestyle interventions aimed at alleviating CVD risk. This article is part of a Special Issue entitled "SI: CV Aging".

Plasma nitric oxide, endothelin-1, arginase and superoxide dismutase in the plasma and placentae from preeclamptic patients

The aim of this study was to determine parameters of NO metabolism in plasma and placenta of preeclamptic (PE) patients. It was conducted a case-control study at São José Hospital, Brazil. Thirty-three PE and 33 normotensive pregnant were included in the study. The diagnosis of PE was established in accordance with the definitions of American College of Obstetricians and Gynecologists. Peripheral venous blood and placenta samples were obtained at postpartum period. Plasma NO levels and SOD activity were significantly lower and endothelin-1 levels and arginase activity were significantly higher in PE women when compared to controls. None of the analyzed parameters were different in the placenta between groups. Our findings suggest that parameters associated with NO metabolism are altered only at the systemic level, but not in placenta of PE patients.

Compared With Radical Nephrectomy, Nephron-sparing Partial Nephrectomy Protects Apolipoprotein E-deficient Mice From Atherosclerosis Progression

OBJECTIVE

To compare the effect of radical with partial unilateral nephrectomy on the development of atherosclerosis in the apolipoprotein E (apoE(-/-))-deficient mouse model.

METHODS

Male apoE(-/-) mice were randomly assigned to the following 3 groups: (1) radical left nephrectomy (RNX, 15 mice), (2) partial left nephrectomy (PNX, 15 mice), and (3) left kidney sham operation (sham-op, 12 mice). The right kidney was left intact in all groups. At 16 weeks after surgery, mice were killed, and atherosclerotic surface area and plaque composition were evaluated in the aortic root and the descending aorta using a quantitative morphologic image processing method.

RESULTS

At killing, RNX mice had significantly higher serum urea, total cholesterol, and triglyceride concentrations than PNX and sham-op groups (P <.05, P <.001, and P <.0001, respectively). Atherosclerotic lesions in the aortic root and the descending aorta were significantly increased in the RNX mice compared with those in the PNX and sham-op mice (P <.05 and P <.001, respectively). In addition, aortic plaques of RNX mice showed a significant increase in nitrotyrosine expression (P <.02) and collagen content (P <.05), whereas the degree of macrophage infiltration was comparable between the groups.

CONCLUSION

We show for the first time that PNX, as compared with RNX, slows the progression of vascular disease in a mouse model of severe atherosclerosis. This effect was mediated by the prevention of chronic kidney disease-induced increases in oxidative stress and lipid disturbances. Our finding can be interpreted as being in support of an expanded use of nephron-sparing techniques in atherosclerosis-prone patients who need to undergo kidney cancer surgery.

Effect of selenium on markers of risk of pre-eclampsia in UK pregnant women: a randomised, controlled pilot trial

Pre-eclampsia is a serious hypertensive condition of pregnancy associated with high maternal and fetal morbidity and mortality. Se intake or status has been linked to the occurrence of pre-eclampsia by our own work and that of others. We hypothesised that a small increase in the Se intake of UK pregnant women of inadequate Se status would protect against the risk of pre-eclampsia, as assessed by biomarkers of pre-eclampsia. In a double-blind, placebo-controlled, pilot trial, we randomised 230 primiparous pregnant women to Se (60 μg/d, as Se-enriched yeast) or placebo treatment from 12 to 14 weeks of gestation until delivery. Whole-blood Se concentration was measured at baseline and 35 weeks, and plasma selenoprotein P (SEPP1) concentration at 35 weeks. The primary outcome measure of the present study was serum soluble vascular endothelial growth factor receptor-1 (sFlt-1), an anti-angiogenic factor linked with the risk of pre-eclampsia. Other serum/plasma components related to the risk of pre-eclampsia were also measured. Between 12 and 35 weeks, whole-blood Se concentration increased significantly in the Se-treated group but decreased significantly in the placebo group. At 35 weeks, significantly higher concentrations of whole-blood Se and plasma SEPP1 were observed in the Se-treated group than in the placebo group. In line with our hypothesis, the concentration of sFlt-1 was significantly lower at 35 weeks in the Se-treated group than in the placebo group in participants in the lowest quartile of Se status at baseline (P= 0·039). None of the secondary outcome measures was significantly affected by treatment. The present finding that Se supplementation has the potential to reduce the risk of pre-eclampsia in pregnant women of low Se status needs to be validated in an adequately powered trial.

Advances in the pathophysiology of pre-eclampsia and related podocyte injury

Pre-eclampsia is a pregnancy-specific hypertensive disorder that may lead to serious maternal and fetal complications. It is a multisystem disease that is commonly, but not always, accompanied by proteinuria. Its cause(s) remain unknown, and delivery remains the only definitive treatment. It is increasingly recognized that many pathophysiological processes contribute to this syndrome, with different signaling pathways converging at the point of systemic endothelial dysfunction, hypertension, and proteinuria. Different animal models of pre-eclampsia have proven utility for specific aspects of pre-eclampsia research, and offer insights into pathophysiology and treatment possibilities. Therapeutic interventions that specifically target these pathways may optimize pre-eclampsia management and may improve fetal and maternal outcomes. In addition, recent findings regarding placental, endothelial, and podocyte pathophysiology in pre-eclampsia provide unique and exciting possibilities for improved diagnostic accuracy. Emerging evidence suggests that testing for urinary podocytes or their markers may facilitate the prediction and diagnosis of pre-eclampsia. In this review, we explore recent research regarding placental, endothelial, and podocyte pathophysiology. We further discuss new signaling and genetic pathways that may contribute to pre-eclampsia pathophysiology, emerging screening and diagnostic strategies, and potential targeted interventions.

Placental protein tyrosine nitration and MAPK in type 1 diabetic pre-eclampsia: Impact of antioxidant vitamin supplementation

AIM

To examine the role of placental protein tyrosine nitration and p38-Mitogen-Activated Protein Kinase α (p38-MAPKα), Extra Cellular-Signal Regulated Kinase (ERK) and c-Jun NH2-Terminal Kinase (JNK) activity, in the pathogenesis of type 1 diabetic pre-eclampsia, and the putative modulation of these indices by maternal vitamin C and E supplementation.

METHODS

Placental samples were obtained from a sub-cohort of the DAPIT trial: a randomised placebo-controlled trial of antioxidant supplementation to reduce pre-eclampsia in type 1 diabetic pregnancy. Placenta from placebo-treated: normotensive (NT) [n=17], gestational hypertension (GH) [n=7] and pre-eclampsia (PE) [n=6] and vitamin-treated: NT (n=20), GH (n=4) and PE (n=3) was analysed. Protein tyrosine nitration was assessed by immunohistochemistry in paraffin-embedded tissue. Catalytic activities of placental p38-MAPKα, ERK and JNK were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Nitrotyrosine immunostaining was present in placebo-treated NT, GH and PE placentae, with no significant difference observed between the groups. There was a non-significant trend towards decreased p38-MAPKα activity in PE vs NT control placentae. ERK and JNK were similar among the three outcome placebo groups and vitamin supplementation did not significantly alter their activity.

CONCLUSION

Nitrotyrosine immunopositivity in normotensive diabetic placentae indicates some degree of tyrosine nitration in uncomplicated diabetic pregnancy, possibly due to inherent oxidative stress and peroxynitrite production. Our results suggest that p38-MAPKα, ERK and JNK are not directly involved in the pathogenesis of type 1 diabetic pre-eclampsia and are not modulated by vitamin-supplementation.

Decreased levels of folate receptor-β and reduced numbers of fetal macrophages (Hofbauer cells) in placentas from pregnancies with severe pre-eclampsia

PROBLEM

Pre-eclampsia (PE), a pregnancy complication of unknown etiology, is a major cause of maternal and fetal mortality and morbidity. Previous studies have described placental genes that are up-regulated in expression in PE, but few studies have addressed placental gene suppression in this syndrome.

METHOD OF STUDY

Gene profiling and quantitative reverse transcription PCR (qRTPCR) analyses were used to identify genes down-regulated in placentas from women with severe preterm PE compared with gestational age-matched normotensive controls with spontaneous preterm birth (sPTB). Western blotting and immunohistochemistry were used to evaluate levels and patterns of cell type-specific protein expression in PE and sPTB group placentas.

RESULTS

Levels of macrophage marker [folate receptor (FR)-β, CD163, and CD68] mRNA and FR-β protein were significantly down-regulated in PE group placentas compared with the sPTB group. Numbers of Hofbauer cells (HBCs, fetal macrophages) and FR-β protein in these cells were reduced in PE group placentas.

CONCLUSION

Severe PE is associated with decreased placental expression of FR-β and a reduction in the number of HBCs. Reduced placental macrophage function is likely to play a key role in the pathophysiology of PE.

Heat shock protein 70 expression is spatially distributed in human placenta and selectively upregulated during labor and preeclampsia

Placental oxidative stress is a feature of both human labor and the pregnancy syndrome preeclampsia. Heat shock proteins (HSPs) can be induced in cells as a protective mechanism to cope with cellular stress. We hypothesized that HSP 70 would increase during labor and preeclampsia and that expression would vary in different placental zones. Samples were obtained from 12 sites within each placenta: 4 equally spaced apart pieces were sampled from the inner, middle and outer placental regions. Non-labor, labor and preeclampsia were studied. HSP 70 expression was investigated by Western blot analysis. HSP 70 protein expression was increased in the middle compared with the outer area (p = 0.03) in non-labor and in both the inner and middle areas compared with the outer area (p = 0.01 and p = 0.02 respectively) in labor. HSP 70 was increased in the preeclampsia non-labor group compared to the control non-labor group in the inner region (p = 0.003) and in the control labor group compared with the preeclampsia labor group at the middle area (p = 0.001). In conclusion HSP 70 is expressed in a spatial manner in the placenta. Changes in HSP 70 expression occur during labor and preeclampsia but at different zones within the placenta. The physiological and pathological significance of these remains to be elucidated but the results have important implications for how data obtained from studies in placental disease (and other organs) can be influenced by sampling methods.

Distal-less 3 haploinsufficiency results in elevated placental oxidative stress and altered fetal growth kinetics in the mouse

Distal-less 3 (Dlx3)(-/-) mice die at E9.5 presumably due to an abnormal placental phenotype including reduced placental vasculature and secretion of placental growth factor. To examine the role of Dlx3 specifically within the epiblast, Dlx3 conditional knockout mice were generated using an epiblast-specific Meox2(CreSor) allele. Dlx3(-/fl), Meox2(CreSor) animals were born at expected frequencies and survived to weaning providing indirect evidence that loss of Dlx3 within the trophoectoderm plays a critical role in fetal survival in the Dlx3(-/-) mouse. We next examined the hypothesis that loss of a single Dlx3 allele would have a negative impact on placental and fetal fitness. Dlx3(+/-) mice displayed reduced fetal growth beginning at E12.5 compared with Dlx3(+/+) controls. Altered fetal growth trajectory occurred coincident with elevated oxidative stress and apoptosis within Dlx3(+/-) placentas. Oral supplementation with the superoxide dismutase mimetic, Tempol, rescued the fetal growth and placental cell death phenotypes in Dlx3(+/-) mice. To determine the potential mechanisms associated with elevated oxidative stress on the Dlx3(+/-) placentas, we next examined vascular characteristics within the feto-placental unit. Studies revealed reduced maternal spiral artery luminal area in the Dlx3(+/-) mice receiving water; Dlx3(+/-) mice receiving Tempol displayed maternal spiral artery luminal area similar to control Dlx3(+/+) mice. We conclude that reduced Dlx3 gene dose results in diminished fetal fitness associated with elevated placental cell oxidative stress and apoptosis coincident with altered vascular remodeling. Administration of antioxidant therapy ameliorated this feto-placental phenotype, suggesting that Dlx3 may be required for adaptation to oxidative stresses within the intrauterine environment.

Oxidative damage to pre-eclamptic placenta: immunohistochemical expression of VEGF, nitrotyrosine residues and von Willebrand factor

OBJECTIVE

To determine the relationship of biomarkers of placental damage by oxidative stress in pre-eclamptic placenta.

METHODS

A case-control study was performed on a population of 14 pregnant women with PE and 12 women with normal pregnancies. Immunohistochemical expressions of VEGF, vWF distribution, (Na + K)-ATPase activity, and abundance of nitrotyrosine residues, were assessed in the placental tissue.

RESULTS

Women with pre-eclampsia showed increased VEGF expression and abundance of nitrotyrosine residues in placental villous, and plasma vWF levels (p < 0.05), whereas placental (Na + K)-ATPase activity were significantly reduced. The syncytiotrophoblast and the maternal space of pre-eclamptic placenta showed diminished and increased vWF expression, respectively, but no significant differences in its expression were found in the placental endothelium and stroma (p < 0.05).

CONCLUSIONS

It could be suggested that increased oxidative stress and VEGF contribute to enhance the impairment of placental perfusion by increasing peroxynitrite formation, product of the NO and superoxide reaction, thereby partly contributing to account for the pathophysiology of this disease. The presence of vWF in the maternal space and its diminished expression in syncytiotrophoblast of pre-eclamptic placenta also might have pathogenic implications.

Placental expression of endothelial and inducible nitric oxide synthase and nitric oxide levels in patients with HELLP syndrome

OBJECTIVE

To determine placental gene expression of endothelial and inducible nitric oxide synthases and measure nitric oxide levels in patients with hemolysis, elevated liver enzyme levels, and low platelet count syndrome.

STUDY DESIGN

Preterm placentas were obtained from 15 patients with hemolysis, elevated liver enzyme levels, and low platelet count syndrome and 30 controls matched for age, parity, and gestational age. mRNA levels were evaluated by real-time polymerase chain reaction, whereas nitric oxide and peroxynitrite production was measured by a commercially available kit.

RESULTS

Placental gene expression of inducible nitric oxide and endothelial nitric oxide synthases were significantly lower in the hemolysis, elevated liver enzyme levels, and low platelet count syndrome group than in controls, whereas nitric oxide and peroxynitrite production were significantly higher in hemolysis, elevated liver enzyme levels, and low platelet count syndrome compared with controls.

CONCLUSION

The reduced endothelial nitric oxide and inducible nitric oxide synthases gene expression in women with hemolysis, elevated liver enzyme levels, and low platelet count syndrome may indicate extreme placental dysfunction that is unable to compensate the endothelial derangement and the related hypertension. The higher nitric oxide formation found in hemolysis, elevated liver enzyme levels, and low platelet count syndrome placentas could be explained as a counteraction to the impaired fetoplacental perfusion, typical of the syndrome.

Nitric oxide and peroxynitrite platelet levels in gestational hypertension and preeclampsia

The aim of the study was to investigate platelet nitric oxide (NO) pathways in women with Gestational Hypertension (GH), Preeclampsia (PE) and Controls. Platelet NO(x) and peroxynitrite (ONOO(-)) levels, inducible (iNOS) and endothelial nitric oxide synthase (eNOS) and Nitrotyrosine expression (N-Tyr) in 30 women with GH, 30 with PE and 30 healthy pregnant controls, age, parity and gestational age-matched, were assessed. Platelet NO(x) and ONOO(-) levels were significantly higher in GH and PE vs. Controls, with higher levels in GH vs. PE. At the same way, iNOS and N-Tyr were significantly higher in GH and PE vs. Controls, with higher levels in GH vs. PE. Since GH expressed higher amount of NO metabolites and higher activation of iNOS compared to PE, we can hypothesize that the severity of hypertensive pathology is almost not related to only NO metabolism, this research confirmed that GH and PE are associated with marked changes in NO pathways; it is not easy to understand if they could be interpreted as causes or consequence of these pathologic states.

8-Hydroxy-2-deoxyguanosine staining in placenta is associated with maternal serum uric acid levels and gestational age at diagnosis in pre-eclampsia

BACKGROUND

Abnormal activation and/or dysfunction of the maternal vascular endothelium have been implicated as a cause of the placental ischemia and oxidative damage associated with pregnancy-induced hypertension (PIH).

METHODS

To clarify the relationship between systemic oxidative stress and placental damage induced by reactive oxygen species (ROS), we immunostained placentas from 27 PIH pregnancies and 41 normal pregnancies for 8-hydroxy-2-deoxyguanosine (8OHdG).

RESULTS

Positive 8OHdG staining was significantly more frequent in the syncytiotrophoblasts from PIH pregnancies compared to normal pregnancies matched for maternal age/gestational age at delivery. Comparison of 8OHdG positive and negative PIH patients revealed that antenatal serum uric acid (UA) was significantly higher, gestational age at delivery was significantly lower and early onset PIH was more frequent in patients with 8OHdG positive staining in the placenta.

CONCLUSION

These results suggest that ROS directly injures the placental syncytiotrophoblast in PIH patients and that elevated UA in PIH patients, at least partly, indicates placental damage induced by ROS. Moreover, the role and significance of ROS injury in the placenta may differ between early onset and late-onset type PIH.

Role of oxidative stress markers and antioxidants in the placenta of preeclamptic patients

AIM

The present study aimed to evaluate and compare the placental variables of oxidative stress markers in preeclamptic women.

METHODS

A total of 60 placentas were collected. Of these, 30 were obtained from normotensive pregnancies, and 30 from pregnancies with preeclampsia as per International Society for the Study of Hypertension in Pregnancy (ISSHP) criteria. Each placental tissue was analyzed for levels of pro-oxidant (malondialdehyde) and antioxidants (glutathione and superoxide dismutase) using the standard enzymatic assays.

RESULTS

Malondialdehyde levels were significantly higher (12.21 ± 4.1 versus 4.7 ± 2.1 nmol/g tissue, P < 0.0001) and glutathione (GSH) levels were significantly lower (0.46 ± 0.37 versus 1.03 ± 0.43 µmol/g tissue, P < 0.0001) in the placentas of preeclamptic women when compared to those of normal pregnancies. Though not statistically significant, decreases in superoxide dismutase levels were observed in placentas of preeclamptic women (4.14 ± 2.25 versus 5.22 ± 2.0 units/mg tissue protein, P < 0.055). Receiver operator characteristic curve analysis of malondialdehyde revealed a sensitivity of 87% and specificity of 87%, at a cutoff value 6.5 nmol/g. Similarly, GSH had a sensitivity of 77% and a specificity of 77% at a cutoff value 0.62 µmol/g.

CONCLUSION

The present study demonstrated that increased placental lipid peroxidation and decreased levels of antioxidants may play an important role in the pathogenesis of preeclampsia. These findings are suggestive of involvement of oxidative stress markers in preeclamptic patients.

L-arginine supplementation in women with chronic hypertension: impact on blood pressure and maternal and neonatal complications

OBJECTIVE

To evaluate L-arginine (L-Arg) supplementation in pregnant women with chronic hypertension and its effects on blood pressure (BP) and maternal and neonatal complications.

METHODS

We enrolled 80 women affected by mild chronic hypertension referred to the High Risk Clinic of the Mother-Infant Department of the University of Modena and Reggio Emilia. Each woman after obtaining oral consent was randomized to receive oral L-Arg versus placebo and thereafter submitted to 24-h ambulatory BP monitoring. The primary outcome was BP change after 10-12 weeks of treatment. Secondary outcomes were as follows: percentage of women on antihypertensive treatment at delivery, maternal, and fetal outcome.

RESULTS

The BP changes after 10-12 weeks of treatment did not differ between groups. A lower percentage of women received antihypertensive drugs in the L-Arg group than the placebo group. The incidence of superimposed preeclampsia indicated delivery before the 34th weeks and certain neonatal complications tended to be higher in the placebo group.

CONCLUSIONS

L-Arg supplementation in pregnant women with mild chronic hypertension does not significantly affect overall BP but is associated with less need for antihypertensive medications and a trend toward fewer maternal and neonatal complications. The results of the study were limited by the small sample size and by the exclusion of women with severe chronic hypertension. In our policy, these patients needed many hypertensive drugs and were normally managed by the cardiologist. Nevertheless, considering the promising results on maternal and fetal outcome, we believe that further studies should be performed to confirm such data and to clarify the role of L-Arg as a protective supplement in high-risk pregnancy.

Redox control in mammalian embryo development

The development of an embryo constitutes a complex choreography of regulatory events that underlies precise temporal and spatial control. Throughout this process the embryo encounters ever changing environments, which challenge its metabolism. Oxygen is required for embryogenesis but it also poses a potential hazard via formation of reactive oxygen and reactive nitrogen species (ROS/RNS). These metabolites are capable of modifying macromolecules (lipids, proteins, nucleic acids) and altering their biological functions. On one hand, such modifications may have deleterious consequences and must be counteracted by antioxidant defense systems. On the other hand, ROS/RNS function as essential signal transducers regulating the cellular phenotype. In this context the combined maternal/embryonic redox homeostasis is of major importance and dysregulations in the equilibrium of pro- and antioxidative processes retard embryo development, leading to organ malformation and embryo lethality. Silencing the in vivo expression of pro- and antioxidative enzymes provided deeper insights into the role of the embryonic redox equilibrium. Moreover, novel mechanisms linking the cellular redox homeostasis to gene expression regulation have recently been discovered (oxygen sensing DNA demethylases and protein phosphatases, redox-sensitive microRNAs and transcription factors, moonlighting enzymes of the cellular redox homeostasis) and their contribution to embryo development is critically reviewed.