Estimation of oxidative products of nitric oxide (nitrates, nitrites) in preeclampsia

Red blood cell in preeclampsia: attenuated nitric oxide generation and enhanced reactive oxygen species formation and eryptosis

Preeclampsia (PE) pathogenesis is strongly related to diminished nitric oxide (NO) bioavailability and enhanced oxidative stress. Emerging evidence suggests that red blood cells (RBCs) eNOS enzyme contributes to systemic NO bioavailability by its ability of both NO and ROS generation. We aimed to investigate RBC eNOS enzyme activity, NO and ROS generation capacity, eryptosis index and aggregation levels in preeclamptic and uncomplicated pregnant women. Fifty-eight PE patients and 36 healthy pregnant women were included to the investigation. RBC eNOS enzyme activity, intracellular NO, calcium and ROS concentrations and eryptosis levels were determined via flow cytometric methods. RBC deformability and aggregation were measured via LORRCA. Intracellular NO and phosphorylated RBC eNOS levels decreased in PE group compared to healthy pregnant group (p < 0.05, p < 0.001 respectively). Intracellular ROS and calcium levels, eryptosis values and aggregation indexes in the PE group were significantly higher than healthy pregnant group (p < 0.05, p < 0.01, p < 0.05, p < 0.05 respectively). Our results demonstrate for the first time that RBC produce lower NO and higher ROS under PE conditions. Further, RBC of PE patients were more prone to eryptosis and aggregation compared to control group. Our results suggest that, in addition to endothelial cells, RBC also contribute to decreased plasma NO bioavailability via producing less NO and high ROS in PE. Considering increased tendency to eryptosis and aggregation, RBC seem to play role in haemodynamic changes of PE pathogenesis.

Evaluation of oxidative stress markers in subtypes of preeclampsia: A systematic review and meta-analysis

Studies about oxidative stress biomarkers revealed different phenotypes between early and late preeclampsia (PE). Despite that, there is extensive evidence of oxidative stress in investigations that combinate forms different of preeclampsia. This study reviews the oxidative stress profile in the PE subtypes and evaluates which markers are altered in the blood and placental tissue. A search was conducted in databases such as MEDLINE, EMBASE, LILACS, and Web of Science without restricting the year and language of publication. The quality of the studies was evaluated by the Newcastle-Ottawa scale and Joanna Briggs Institute for analytical Cross-Sectional Studies. After 13,319 screened records, 65 were included in the systematic review. The markers of stress oxidative of damage and reactive species were those selected, such as malondialdehyde (MDA), lipid peroxide, advanced protein oxidation products, carbonyl protein, 8-hydroxy-2'-deoxyguanosine, total oxidant status, hydrogen peroxide, nitric oxide (NO). We described the antioxidant activity, including the superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase, free glutathione, and total antioxidant capacity (TAC). We results demonstrated that oxidative stress is related to pathophysiology of PE, there were increased lipid peroxidation in the blood and placenta, and in blood a reduction of NO levels and of TAC, like lower enzymatic activity of GPx, CAT in PE, and SOD in mild PE. In addition, altered levels of MDA in the placenta and blood show that placental changes have repercussions on the clinical syndrome and are related to the severity of the disease.

Actions of Esomeprazole on the Maternal Vasculature in Lean and Obese Pregnant Mice with Impaired Nitric Oxide Synthesis: A Model of Preeclampsia

Preeclampsia is a devastating, multisystem disorder of pregnancy. It has no cure except delivery, which if premature can impart significant neonatal morbidity. Efforts to repurpose pregnancy-safe therapeutics for the treatment of preeclampsia have led to the assessment of the proton pump inhibitor, esomeprazole. Preclinically, esomeprazole reduced placental secretion of anti-angiogenic sFlt-1, improved endothelial dysfunction, promoted vasorelaxation, and reduced maternal hypertension in a mouse model. Our understanding of the precise mechanisms through which esomeprazole works to reduce endothelial dysfunction and enhance vasoreactivity is limited. Evidence from earlier studies suggested esomeprazole might work via the nitric oxide pathway, upregulating endothelial nitric oxide synthase (eNOS). Here, we investigated the effect of esomeprazole in a mouse model of L-NAME-induced hypertension (decreased eNOS activity). We further antagonised the model by addition of diet-induced obesity, which is relevant to both preeclampsia and the nitric oxide pathway. Esomeprazole did not decrease blood pressure in this model, nor were there any alterations in vasoreactivity or changes in foetal outcomes in lean mice. We observed similar findings in the obese mouse cohort, except esomeprazole treatment enhanced ex vivo acetylcholine-induced vasorelaxation. As acetylcholine induces nitric oxide production, these findings hint at a function for esomeprazole in the nitric oxide pathway.

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.

Reactive Species Interactome Alterations in Oocyte Donation Pregnancies in the Absence and Presence of Pre-Eclampsia

In pregnancy, maternal physiology is subject to considerable adaptations, including alterations in cardiovascular and metabolic function as well as development of immunological tolerance towards the fetus. In an oocyte donation pregnancy, the fetus is fully allogeneic towards the mother, since it carries both oocyte donor antigens and paternal antigens. Therefore, oocyte donation pregnancies result in an immunologically challenging pregnancy, which is reflected by a higher-than-normal risk to develop pre-eclampsia. Based on the allogeneic conditions in oocyte donation pregnancies, we hypothesized that this situation may translate into alterations in concentration of stable readouts of constituents of the reactive species interactome (RSI) compared to normal pregnancies, especially serum free thiols, nitric oxide (NO) and hydrogen sulfide (H₂S) related metabolites. Indeed, total free thiol levels and nitrite (NO₂-) concentrations were significantly lower whereas protein-bound NO and sulfate (SO₄2-) concentrations were significantly higher in both oocyte donation and naturally conceived pregnancies complicated by pre-eclampsia. The increased concentrations of nitrite observed in uncomplicated oocyte donation pregnancies suggest that endothelial NO production is compensatorily enhanced to lower vascular tone. More research is warranted on the role of the RSI and bioenergetic status in uncomplicated oocyte donation pregnancies and oocyte donation pregnancies complicated by pre-eclampsia.

Immune modulation of i.v. immunoglobulin in women with reproductive failure

Background

The mechanism of maternal immune tolerance of the semi‐allogenic fetus has been explored extensively. The immune reaction to defend from invasion by pathogenic microorganisms should be maintained during pregnancy. An imbalance between the immune tolerance to the fetus and immune activation to the pathogenic organisms is associated with poor pregnancy outcomes. This emphasizes that the immune mechanism of successful reproduction is not just immune suppression, but adequate immune modulation.

Methods

In this review, the action of i.v. immunoglobulin G (IVIg) on the immune system and its efficacy in reproductive failure (RF) was summarized. Also suggested is the indication of IVIg therapy for women with RF.

Main findings (Results)

Based on the mechanism of the immune regulation of IVIg and following confirmation of the immune modulation effects of it in various aberrant immune parameters in patients with RF, it is obvious that IVIg is effective in recurrent pregnancy losses and repeated implantation failures with immunologic disturbances.

Conclusion

The authors recommend IVIg therapy in patients with RF with aberrant cellular immunologic parameters, including a high natural killer cell proportion and its cytotoxicity or elevated T helper 1 to T helper 2 ratio, based on each clinic's cut‐off values. Further clinical studies about the safety of IVIg in the fetus and its efficacy in other immunologic abnormalities of RF are needed.

Altered Endothelial Nitric Oxide Signaling as a Paradigm for Maternal Vascular Maladaptation in Preeclampsia

PURPOSE OF REVIEW

The goal of this review is to present the newest insights into what we view as a central failure of cardiovascular adaptation in preeclampsia (PE) by focusing on one clinically significant manifestation of maternal endothelial dysfunction: nitric oxide signaling. The etiology, symptoms, and current theories of the PE syndrome are described first, followed by a review of the available evidence, and underlying causes of reduced endothelial nitric oxide (NO) signaling in PE.

RECENT FINDINGS

PE maladaptations include, but are not limited to, altered physiological stimulatory inputs (e.g., estrogen; VEGF/PlGF; shear stress) and substrates (L-Arg; ADMA), augmented placental secretion of anti-angiogenic and inflammatory factors such as sFlt-1 and Eng, changes in eNOS (polymorphisms, expression), and reduced bioavailability of NO secondary to oxidative stress. PE is a complex obstetrical syndrome that is associated with maternal vascular dysfunction. Diminished peripheral endothelial vasodilator influence in general, and of NO signaling specifically, are key in driving disease progression and severity.

The Role of Decidual Macrophages During Normal and Pathological Pregnancy

Macrophages perform many specific functions including host defense, homeostasis, angiogenesis, and tissue development. Macrophages are the second most abundant leukocyte population in the non-pregnant endometrium and pregnant decidua and likely play a central role in the establishment and maintenance of normal pregnancy. Importantly, aberrantly activated uterine macrophages can affect trophoblast function and placental development, which may result in various adverse pregnancy outcomes ranging from pre-eclampsia to fetal growth restriction or demise. Only by fully understanding the roles of macrophage in pregnancy will we be able to develop interventions for the treatment of these various pregnancy complications. This review discusses the general origin and classification of monocytes and macrophages and focuses on the phenotype and functional roles of decidual macrophage at the maternal-fetal interface in normal pregnancy, as well as discussing the potential contribution of the abnormal state of these cells to various aspects of pregnancy pathologies.

HLA Class Ib Molecules and Immune Cells in Pregnancy and Preeclampsia

Despite decades of research, the highly prevalent pregnancy complication preeclampsia, “the disease of theories,” has remained an enigma. Indeed, the etiology of preeclampsia is largely unknown. A compiling amount of studies indicates that the pathological basis involves a complex array of genetic predisposition and immunological maladaptation, and that a contribution from the mother, the father, and the fetus is likely to be important. The Human Leukocyte Antigen (HLA)-G is an increasing focus of research in relation to preeclampsia. The HLA-G molecule is primarily expressed by the extravillous trophoblast cells lining the placenta together with the two other HLA class Ib molecules, HLA-E and HLA-F. Soluble isoforms of HLA-G have been detected in the early endometrium, the matured cumulus–oocyte complex, maternal blood of pregnant women, in umbilical cord blood, and lately, in seminal plasma. HLA-G is believed to be involved in modulating immune responses in the context of vascular remodeling during pregnancy as well as in dampening potential harmful immune attacks raised against the semi-allogeneic fetus. In addition, HLA-G genetic variants are associated with both membrane-bound and soluble forms of HLA-G, and, in some studies, with preeclampsia. In this review, a genetic contribution from the mother, the father, and the fetus, together with the presence and function of various immune cells of relevance in pregnancy are reviewed in relation to HLA-G and preeclampsia.

Endothelial dysfunction and preeclampsia: role of oxidative stress

Preeclampsia (PE) is an often fatal pathology characterized by hypertension and proteinuria at the 20th week of gestation that affects 5-10% of the pregnancies. The problem is particularly important in developing countries in where the incidence of hypertensive disorders of pregnancy is higher and maternal mortality rates are 20 times higher than those reported in developed countries. Risk factors for the development of PE include obesity, insulin resistance and hyperlipidemia that stimulate inflammatory cytokine release and oxidative stress leading to endothelial dysfunction (ED). However, how all these clinical manifestations concur to develop PE is still not very well understood. The related poor trophoblast invasion and uteroplacental artery remodeling described in PE, increases reactive oxygen species (ROS), hypoxia and ED. Here we aim to review current literature from research showing the interplay between oxidative stress, ED and PE to the outcomes of current clinical trials aiming to prevent PE with antioxidant supplementation.

Innate immunity, decidual cells, and preeclampsia

Preeclampsia (PE) manifested by hypertension and proteinuria complicates 3% to 8% of pregnancies and is a leading cause of fetal-maternal morbidity and mortality worldwide. It may lead to intrauterine growth restriction, preterm delivery, and long-term sequelae in women and fetuses, and consequently cause socioeconomic burden to the affected families and society as a whole. Balanced immune responses are required for the maintenance of successful pregnancy. Although not a focus of most studies, decidual cells, the major resident cell type at the fetal-maternal interface, have been shown to modulate the local immune balance by interacting with other cell types, such as bone marrow derived-immune cells, endothelial cells, and invading extravillous trophoblasts. Accumulating evidence suggests that an imbalanced innate immunity, facilitated by decidual cells, plays an important role in the pathogenesis of PE. Thus, this review will discuss the role of innate immunity and the potential contribution of decidual cells in the pathogenesis of PE.

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.

Analysis of nitroso-proteomes in normotensive and severe preeclamptic human placentas

Nitric oxide (NO) plays a key role in placental biology, and placental dysfunction is the main pathogenesis pathway for preeclampsia, yet the direct placental targets of NO actions have not been determined. Covalent adduction of an NO moiety to cysteines, termed S-nitrosylation (SNO), is emerging as a key route by which NO can directly modulate protein functions. This study was conducted to analyze global S-nitroso (SNO)-proteins in human placentas and to determine if their levels differ in normotensive versus severe preeclamptic placentas. Although total nitrite/nitrate increased, total levels of SNO-proteins and nitrosylated forms of endothelial NO synthase and heat shock protein 90 were decreased by preeclampsia. We further compared normotensive and preeclamptic placental nitroso-proteomes (total SNO-protein profiles) by using a biotin and CyDye switch test combined with two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) and identified SNO-proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Numerous SNO-proteins were displayed as spots on 2D-DIGE gels. One hundred spots of interest were excised; 46 spots were identified, of which 8 spots were novel SNO-proteins; levels of 15 spots were increased, and 6 spots were decreased, and the rest were unchanged by preeclampsia. Pathway analysis suggested that placental SNO-proteins are involved in regulating various cellular functions including protein synthesis, cell movement and metabolism, cell signaling, and other functions. These data therefore show for the first time that SNO is a crucial mechanism by which NO directly regulates placental proteins linked to various biological pathways. The significantly altered placental nitroso-proteome in preeclampsia suggests that SNO plays a role in the placental pathophysiology in preeclampsia.

Preeclamptic placental stress and over expression of mitochondrial HSP70

BACKGROUND

Evidence is accumulating that mitochondrial (Mt) oxidative stress plays a role in the pathogenesis of preeclampsia. The current study analyzes the stress levels, energy status and associated enzymatic alteration in placental mitochondria of preeclamptic (n=30) and normotensive (n=35) subjects.

METHODS

Total Mt stress was measured using dichlorofluorescin (DCFH) oxidant analysis, malondialdehyde (MDA) concentrations, protein carbonyl (PC) concentrations and measurement of nitrite (NO2(-)) and nitrate (NO3(-)). Activity of antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GPx) and the glutathione redox ratio (GRR) were measured. The ATP/ADP (adenosine triphosphate/adenosine diphosphate) concentrations and respiratory chain enzyme activities were also analyzed. The expression of heat shock protein 70 (HSP70) was measured in mitochondria.

RESULTS

The DCFH oxidants, MDA, PC concentrations, and concentrations of NO2(-) and NO3(-) were significantly higher in the preeclamptic group (p<0.01) compared with the control group. The activities of SOD, GPx, GRR [glutathione (GSH)/glutathione disulfate (GSSG)] (p<0.01, p<0.001), ATP/ADP and respiratory chain enzyme activities were reduced significantly (p<0.001) in preeclamptic conditions. The placental mitochondrial HSP70 (mtHSP70) showed significant over expression in the preeclamptic group (p<0.001) compared with the control group.

CONCLUSIONS

These results provide the first line of evidence for accumulated Mt stress demonstrated by increased stress markers, decreased antioxidants and enhanced mtHSP70. The study illustrates the probable protective mechanism of mtHSP70 against the generated stress. This is primarily to combat the enzymatic and free radical mediated damage produced in preeclampsia.

Innate immunity, coagulation and placenta-related adverse pregnancy outcomes

Maternal immunity undergoes subtle adjustment in order to tolerate the semi-allogeneic embryo and maintain the host defense against potential pathogens. Concomitantly, coagulation systems change from an anti-coagulant state to a pro-coagulant state to meet the hemostatic challenge of placentation and delivery. Innate immunity and blood coagulation systems are the first line of defense to protect a host against exogenous challenges, including alloantigens and mechanical insults, and preserve the integrity of an organism. The interactions between coagulation and immune systems have been extensively studied. Immune cells play a pivotal role in the initiation of the coagulation cascade, whereas coagulation proteases display substantial immuno-modulatory effects. Upon exogenous challenges, the immune and coagulation systems are capable of potentiating each other leading to a vicious cycle. Natural killer (NK) cells, macrophages (Mphis) and dendritic cells (DCs) are three major innate immune cells that have been demonstrated to play essential roles in early pregnancy. However, immune maladaptation and hemostatic imbalance have been suggested to be responsible for adverse pregnant outcomes, such as preeclampsia (PE), miscarriage, recurrent spontaneous abortion (RSA) and intrauterine growth restriction (IUGR). In this review, we will summarize the mutual regulation between blood coagulation and innate immune systems as well as their roles in the maintenance of normal pregnancy and in the pathogenesis of adverse pregnancy outcomes.

Nitric Oxide, Lipid Peroxides, and Uric Acid Levels in Pre-Eclampsia and Eclampsia

The aim was to study the role of nitric oxide (NO), lipid peroxides (LPX), and uric acid in pre-eclampsia and eclampsia. Plasma levels of NO metabolites (nitrite+nitrate), malonyldialdehyde (MDA), and uric acid and erythrocyte MDA levels were compared between normal pregnant, pre-eclamptic, and eclamptic pregnant women in third trimester. Student's t-test was used for statistical evaluation. Plasma NO metabolites levels were higher in eclamptic group (35.7 +/- 16.5 micromol/liter, p < 0.05) but not in pre-eclamptic group (22.1 +/- 10.8 micromol/liter) than control group (18.8 +/- 6.9 micromol/liter). Plasma MDA and uric acid concentrations were higher in preeclamptic (4.4 +/- 1.7 nmol/ml, p < 0.05; 0.45 +/- 0.11 mmol/liter, p < 0.05, respectively) and eclamptic (5.8 +/- 1.9 nmol/ml, p < 0.05; 0.47 +/- 0.12 mmol/liter, p < 0.05) groups compared with control group (3.0 +/- 1.3 nmol/ml; 0.35 +/- 0.06 mmol/liter). Erythrocytes MDA concentrations were higher only in eclamptic group (174.4 +/- 62 nmol/gHb, p < 0.05) than control group (139.2 +/- 49.5 nmol/gHb). These results suggest that NO, LPX, and uric acid are important factors in the pathogenesis of pre-eclampsia and eclampsia, and that NO production and LPX are directly related to the severity of disease.

Altered vascular function in healthy normotensive pregnant women with bilateral uterine artery notches

OBJECTIVES

To assess endothelial function and vascular mechanical properties in normotensive pregnant women with high resistance in the uteroplacental circulation.

DESIGN

Cross-sectional prospective study.

SETTING

Doppler ultrasound laboratory at university department of obstetrics and gynaecology referral centre for high risk pregnancies.

PARTICIPANTS

Forty-two caucasian normotensive pregnant women: 23 with uncomplicated pregnancies and 19 with bilateral uterine artery notches.

METHODS

Flow-mediated dilatation of the brachial artery was measured by ultrasonography at 25 gestational weeks. Concentrations of nitrite and nitrate in the plasma were established at 25 and 32 gestational weeks. The elastic properties of the common carotid artery, abdominal aorta and popliteal artery were measured with an ultrasonic echo-tracking system.

RESULTS

Flow-mediated dilatation at two minutes after cuff deflation was significantly lower in the bilateral notch group compared with the control group, 8.3% and 13.7%, respectively (P = 0.0007). The ability to sustain vasodilatation was reduced in the bilateral notch group (P = 0.02). Lower values of nitrite and nitrate in the plasma were found at 32 gestational weeks in the bilateral notch group than in the control group (mean 24.76 microM/L (SD 5.6) and 30.93 microM/L (8.2), respectively; P = 0.008). Nitrite and nitrate levels tended to be lower in the bilateral notch group even at 25 gestational weeks (29.45 microM/L (8.3) and 35.73 microM/L (11.0) in the bilateral notch and control group, respectively; P = 0.09). There was no difference in aortic, carotid or popliteal elasticity between the two groups.

CONCLUSIONS

Healthy normotensive pregnant women with bilateral uterine artery notches show impaired endothelial function, but no differences in vascular mechanical properties.

Nitric oxide dysfunction in the pathophysiology of preeclampsia

Researchers disagree as to the importance of nitric oxide (NO) in preeclampsia. Many researchers have alluded to NO's possible primary or secondary role in the development of preeclampsia, but few have correlated the dysfunction of nitric oxide production with the other metabolic derangements seen in this condition. This paper will review the evidence that the primary dysfunction in preeclampsia is a relative deficiency of available NO (secondary to oxidative degradation) and an excess of peroxynitrite (ONOO(-)). The combination of a deficiency of NO and an increase in ONOO(-) can directly or indirectly initiate the vast majority of physiological and serological changes associated with preeclampsia, such as blood pressure, increased glomerular filtration rate, proteinuria, platelet dysfunction, increased thromboxane and endothelin, and a decrease in prostacyclin. Understanding the complex role of nitric oxide in this condition may explain why previous interventions have been unsuccessful and suggest possible strategies for prevention and treatment in the future.