Role of nitric oxide in placental vascular development and function

Action and therapeutic targets of myosin light chain kinase, an important cardiovascular signaling mechanism

The global incidence of cardiac diseases is increasing, imposing a substantial socioeconomic burden on healthcare systems. The pathogenesis of cardiovascular disease is complex and not fully understood, and the physiological function of the heart is inextricably linked to well-regulated cardiac muscle movement. Myosin light chain kinase (MLCK) is essential for myocardial contraction and diastole, cardiac electrophysiological homeostasis, vasoconstriction of vascular nerves and blood pressure regulation. In this sense, MLCK appears to be an attractive therapeutic target for cardiac diseases. MLCK participates in myocardial cell movement and migration through diverse pathways, including regulation of calcium homeostasis, activation of myosin light chain phosphorylation, and stimulation of vascular smooth muscle cell contraction or relaxation. Recently, phosphorylation of myosin light chains has been shown to be closely associated with the activation of myocardial exercise signaling, and MLCK mediates systolic and diastolic functions of the heart through the interaction of myosin thick filaments and actin thin filaments. It works by upholding the integrity of the cytoskeleton, modifying the conformation of the myosin head, and modulating innervation. MLCK governs vasoconstriction and diastolic function and is associated with the activation of adrenergic and sympathetic nervous systems, extracellular transport, endothelial permeability, and the regulation of nitric oxide and angiotensin II. Additionally, MLCK plays a crucial role in the process of cardiac aging. Multiple natural products/phytochemicals and chemical compounds, such as quercetin, cyclosporin, and ML-7 hydrochloride, have been shown to regulate cardiomyocyte MLCK. The MLCK-modifying capacity of these compounds should be considered in designing novel therapeutic agents. This review summarizes the mechanism of action of MLCK in the cardiovascular system and the therapeutic potential of reported chemical compounds in cardiac diseases by modifying MLCK processes.

Modeling the human placenta: in vitro applications in developmental and reproductive toxicology

During its temporary tenure, the placenta has extensive and specialized functions that are critical for pre- and post-natal development. The consequences of chemical exposure in utero can have profound effects on the structure and function of pregnancy-associated tissues and the life-long health of the birthing person and their offspring. However, the toxicological importance and critical functions of the placenta to embryonic and fetal development and maturation have been understudied. This narrative will review early placental development in humans and highlight some in vitro models currently in use that are or can be applied to better understand placental processes underlying developmental toxicity due to in utero environmental exposures.

CCN1-Mediated Signaling in Placental Villous Tissues after SARS-CoV-2 Infection in Term Pregnant Women: Implications for Dysregulated Angiogenesis

The global spread of SARS-CoV-2 has increased infections among pregnant women. This study aimed to explore placental pathology alterations and angiogenic factor levels in term pregnant women after SARS-CoV-2 infection in a retrospective single-center study. Additionally, we investigated the role and underlying mechanism of the vascular inflammation-promoting, cysteine-rich protein 61 (CYR61/CCN1) in this context. All analyses were performed in term pregnant women infected with or without SARS-CoV-2. The sFlt-1, PlGF, and sEng serum levels were quantified using ELISA. Placental protein expressions were examined by immunoblot and immunostaining. Additionally, the effect of CCN1 protein on SGHPL-5 trophoblast cells was examined. We found that SARS-CoV-2 activated the inflammatory response in pregnant women, leading to pronounced vascular alterations in placental villous tissues. Elevated serum anti-angiogenic factors (sFlt-1, sEng) upon SARS-CoV-2 infection may directly contribute to these pathological changes. Upregulated CCN1 and pNF-κB in placental villous tissues of infected patients are identified as crucial factors in placental alterations. As a conclusion, CCN1 was significantly elevated in the placentas of term pregnant women infected with SARS-CoV-2. By activating a cascade of inflammatory responses, CCN1 induced the production of the anti-angiogenic factors sFlt-1 and sEng, which may lead to abnormal placental vascular architecture.

Do Genetic Variants Modify the Effect of Smoking on Risk of Preeclampsia in Pregnancy?

OBJECTIVE

 Maternal smoking is associated with as much as a 50% reduced risk of preeclampsia, despite increasing risk of other poor pregnancy outcomes that often co-occur with preeclampsia, such as preterm birth and fetal growth restriction. Researchers have long sought to understand whether this perplexing association is biologically based, or a result of noncausal mechanisms. We examined whether smoking-response genes modify the smoking-preeclampsia association to investigate potential biological explanations.

STUDY DESIGN

 We conducted a nested case-control study within the Norwegian Mother, Father and Child Birth Cohort (1999-2008) of 2,596 mother-child dyads. We used family-based log-linear Poisson regression to examine modification of the maternal smoking-preeclampsia relationship by maternal and fetal single nucleotide polymorphisms involved in cellular processes related to components of cigarette smoke (n = 1,915 with minor allele frequency ≥10%). We further investigated the influence of smoking cessation during pregnancy.

RESULTS

 Three polymorphisms showed overall (p < 0.001) multiplicative interaction between smoking and maternal genotype. For rs3765692 (TP73) and rs10770343 (PIK3C2G), protection associated with smoking was reduced with two maternal copies of the risk allele and was stronger in continuers than quitters (interaction p = 0.02 for both loci, based on testing 3-level smoking by 3-level genotype). For rs2278361 (APAF1) the inverse smoking-preeclampsia association was eliminated by the presence of a single risk allele, and again the trend was stronger in continuers than in quitters (interaction p = 0.01).

CONCLUSION

 Evidence for gene-smoking interaction was limited, but differences by smoking cessation warrant further investigation. We demonstrate the potential utility of expanded dyad methods and gene-environment interaction analyses for outcomes with complex relationships between maternal and fetal genotypes and exposures.

KEY POINTS

· Maternal and fetal genotype may differentially influence preeclampsia.. · Smoking-related genes did not strongly modify smoking-preeclampsia association.. · Smoking cessation reduced strength of gene by smoking interactions..

Transplacental infection by bovine alphaherpesvirus type 1 induces protein expression of COX-2, iNOS and inflammatory cytokines in fetal lungs and placentas

Bovine alphaherpesvirus type 1 (BoAHV-1) is associated with respiratory and reproductive syndromes. Until present the immunologic mechanisms involved in BoAHV-1 abortion are partially known. We studied key elements of the innate immune response in the placentas and fetal lungs from cattle experimentally-inoculated with BoAHV-1. These tissues were analyzed by histopathology. Furthermore, virus identification was performed by qPCR and the expression of the inflammatory cytokines such as tumor necrosis factor-alpha, interleukin 1-alpha and inflammatory mediators like inducible nitric oxide synthase and cyclooxeganse-2 was evaluated by immunohistochemistry. The viral transplacental infection was confirmed by the detection of BoAHV-1 by qPCR in the placenta and fetal organs, which revealed mild inflammatory lesions. Inducible nitric oxide synthase immunolabelling was high in the lungs of infected fetuses and placentas, as well as for tumor necrosis factor-alpha in the pulmonary parenchyma and cyclooxeganse-2 in fetal annexes. However, the expression of interleukin 1-alpha was weak in these organs. To our knowledge, this is the first study that provides strong evidence of an early immune response to BoAHV-1 infection in the conceptus. Advances in the knowledge of the complex immunological interactions at the feto-maternal unit during BoAHV-1 infection are needed to clarify the pathogenesis of abortion.

Should the non-canonical pathway of nitric oxide generation be targeted in hypertensive pregnancies?

Hypertension in pregnancy is prevalent, affecting around 10% of pregnancies worldwide, and significantly increases the risk of adverse outcomes for both mothers and their babies. Current treatment strategies for pregnant women with hypertension are limited, and new approaches for the management of hypertension in pregnancy are urgently needed. Substantial evidence from non-pregnant subjects has demonstrated the potential for dietary nitrate supplementation to increase nitric oxide (NO) bioavailability and lower blood pressure, following bioactivation via the non-canonical NO pathway. Emerging data suggest this approach may also be of benefit in pregnant women, although studies are limited. This review aims to summarise the current evidence from preclinical and clinical studies of nitrate supplementation in pregnancy, drawing on data from non-pregnant populations where appropriate and highlighting key gaps in knowledge that remain to be addressed in future trials.

Shared developmental pathways of the placenta and fetal heart

Congenital heart defects (CHD) remain the most common class of birth defect worldwide, affecting 1 in every 110 live births. A host of clinical and morphological indicators of placental dysfunction are observed in pregnancies complicated by fetal CHD and, with the recent emergence of single-cell sequencing capabilities, the molecular and physiological associations between the embryonic heart and developing placenta are increasingly evident. In CHD pregnancies, a hostile intrauterine environment may negatively influence and alter fetal development. Placental maldevelopment and dysfunction creates this hostile in-utero environment and may manifest in the development of various subtypes of CHD, with downstream perfusion and flow-related alterations leading to yet further disruption in placental structure and function. The adverse in-utero environment of CHD-complicated pregnancies is well studied, however the specific etiological role that the placenta plays in CHD development remains unclear. Many mouse and rat models have been used to characterize the relationship between CHD and placental dysfunction, but these paradigms present substantial limitations in the assessment of both the heart and placenta. Improvements in non-invasive placental assessment can mitigate these limitations and drive human-specific investigation in relation to fetal and placental development. Here, we review the clinical, structural, and molecular relationships between CHD and placental dysfunction, the CHD subtype-dependence of these changes, and the future of Placenta-Heart axis modeling and investigation.

The NOS/NO System in Renal Programming and Reprogramming

Nitric oxide (NO) is a gaseous signaling molecule with renoprotective properties. NO can be produced in NO synthase (NOS)-dependent or -independent manners. NO deficiency plays a decisive role in chronic kidney disease (CKD). Kidney development can be affected in response to adverse intrauterine conditions that induce renal programming, thereby raising the risk of developing CKD in adulthood. Conversely, detrimental programming processes could be postponed or halted prior to the onset of CKD by early treatments, namely reprogramming. The current review provides an overview of the NOS/NO research performed in the context of renal programming and reprogramming. NO deficiency has been increasingly found to interact with the different mechanisms behind renal programming, such as oxidative stress, aberrant function of the renin-angiotensin system, disturbed nutrient-sensing mechanisms, dysregulated hydrogen sulfide signaling, and gut microbiota dysbiosis. The supplementation of NOS substrates, the inhibition of asymmetric dimethylarginine (ADMA), the administration of NO donors, and the enhancement of NOS during gestation and lactation have shown beneficial effects against renal programming in preclinical studies. Although human data on maternal NO deficiency and offspring kidney disease are scarce, experimental data indicate that targeting NO could be a promising reprogramming strategy in the setting of renal programming.

Involvement of metalloproteinase and nitric oxide synthase/nitric oxide mechanisms in early decidual angiogenesis-vascularization of normal and experimental pathological mouse placenta related to maternal alcohol exposure

Successful pregnancy for optimal fetal growth requires adequate early angiogenesis and remodeling of decidual spiral arterioles during placentation. Prior to the initiation of invasion and endothelial replacement by trophoblasts, interactions between decidual stromal cells and maternal leukocytes, such as uterine natural killer cells and macrophages, play crucial roles in the processes of early maternal vascularization, such as proliferation, apoptosis, migration, differentiation, and matrix and vessel remodeling. These placental angiogenic events are highly dependent on the coordination of several mechanisms at the early maternal-fetal interface, and one of them is the expression and activity of matrix metalloproteinases (MMPs) and endothelial nitric oxide synthases (NOSs). Inadequate balances of MMPs and nitric oxide (NO) are involved in several placentopathies and pregnancy complications. Since alcohol consumption during gestation can affect fetal growth associated with abnormal placental development, recently, we showed, in a mouse model, that perigestational alcohol consumption up to organogenesis induces fetal malformations related to deficient growth and vascular morphogenesis of the placenta at term. In this review, we summarize the current knowledge of the early processes of maternal vascularization that lead to the formation of the definitive placenta and the roles of angiogenic MMP and NOS/NO mechanisms during normal and altered early gestation in mice. Then, we propose hypothetical defective decidual cellular and MMP and NOS/NO mechanisms involved in abnormal decidual vascularization induced by perigestational alcohol consumption in an experimental mouse model. This review highlights the important roles of decidual cells and their MMP and NOS balances in the physiological and pathophysiological early maternal angiogenesis-vascularization during placentation in mice.

Sodium Nitrite Attenuates Reduced Activity of Vascular Matrix Metalloproteinase-2 and Vascular Hyper-Reactivity and Increased Systolic Blood Pressure Induced by the Placental Ischemia Model of Preeclampsia in Anesthetized Rats

Preeclampsia is a maternal hypertension disorder associated with vascular dysfunction and fetal and placental growth restrictions. Placental ischemia is suggested as the primary trigger of preeclampsia-associated impairments of both endothelium-derived nitric oxide (NO) and the vascular activity of extracellular matrix metalloproteinase-2 (MMP-2). Reduced uteroplacental perfusion pressure (RUPP) is a placental ischemia model of preeclampsia. Reduction of sodium nitrite to NO may occur during ischemic conditions. However, sodium nitrite effects in the RUPP model of preeclampsia have not yet been investigated. Pregnant rats were divided into four groups: normotensive pregnant rats (Norm-Preg), pregnant rats treated with sodium nitrite (Preg + Nitrite), preeclamptic rats (RUPP), and preeclamptic rats treated with sodium nitrite (RUPP + Nitrite). Maternal blood pressure and fetal and placental parameters were recorded. Vascular function, circulating NO metabolites, and the gelatinolytic activity of vascular MMP-2 were also examined. Sodium nitrite attenuates increased blood pressure, prevents fetal and placental weight loss, counteracts vascular hyper-reactivity, and partially restores NO metabolites and MMP-2 activity. In conclusion, sodium nitrite reduction to NO may occur during RUPP-induced placental ischemia, thereby attenuating increased blood pressure, fetal and placental growth restriction, and vascular hyper-reactivity associated with preeclampsia and possibly restoring NO and MMP-2 activity, which underlie the blood pressure-lowering effects.

Interventions affecting the nitric oxide pathway versus placebo or no therapy for fetal growth restriction in pregnancy

BACKGROUND

Fetal growth restriction (FGR) is a condition of poor growth of the fetus in utero. One of the causes of FGR is placental insufficiency. Severe early-onset FGR at < 32 weeks of gestation occurs in an estimated 0.4% of pregnancies. This extreme phenotype is associated with a high risk of fetal death, neonatal mortality, and neonatal morbidity. Currently, there is no causal treatment, and management is focused on indicated preterm birth to prevent fetal death. Interest has risen in interventions that aim to improve placental function by administration of pharmacological agents affecting the nitric oxide pathway causing vasodilatation.

OBJECTIVES

The objective of this systematic review and aggregate data meta-analysis is to assess the beneficial and harmful effects of interventions affecting the nitric oxide pathway compared with placebo, no therapy, or different drugs affecting this pathway against each other, in pregnant women with severe early-onset FGR.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (16 July 2022), and reference lists of retrieved studies.

SELECTION CRITERIA

We considered all randomised controlled comparisons of interventions affecting the nitric oxide pathway compared with placebo, no therapy, or another drug affecting this pathway in pregnant women with severe early-onset FGR of placental origin, for inclusion in this review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane Pregnancy and Childbirth methods for data collection and analysis.

MAIN RESULTS

We included a total of eight studies (679 women) in this review, all of which contributed to the data and analysis. The identified studies report on five different comparisons: sildenafil compared with placebo or no therapy, tadalafil compared with placebo or no therapy, L-arginine compared with placebo or no therapy, nitroglycerin compared with placebo or no therapy and sildenafil compared with nitroglycerin. The risk of bias of included studies was judged as low or unclear. In two studies the intervention was not blinded. The certainty of evidence for our primary outcomes was judged as moderate for the intervention sildenafil and low for tadalafil and nitroglycerine (due to low number of participants and low number of events). For the intervention L-arginine, our primary outcomes were not reported. Sildenafil citrate compared to placebo or no therapy (5 studies, 516 women) Five studies (Canada, Australia and New Zealand, the Netherlands, the UK and Brazil) involving 516 pregnant women with FGR were included. We assessed the certainty of the evidence as moderate. Compared with placebo or no therapy, sildenafil probably has little or no effect on all-cause mortality (risk ratio (RR) 1.01, 95% confidence interval (CI) 0.80 to 1.27, 5 studies, 516 women); may reduce fetal mortality (RR 0.82, 95% CI 0.60 to 1.12, 5 studies, 516 women), and increase neonatal mortality (RR 1.45, 95% CI 0.90 to 2.33, 5 studies, 397 women), although the results are uncertain for fetal and neonatal mortality as 95% confidence intervals are wide crossing the line of no effect. Tadalafil compared with placebo or no therapy (1 study, 87 women) One study (Japan) involving 87 pregnant women with FGR was included. We assessed the certainty of the evidence as low. Compared with placebo or no therapy, tadalafil may have little or no effect on all-cause mortality (risk ratio 0.20, 95% CI 0.02 to 1.60, one study, 87 women); fetal mortality (RR 0.11, 95% CI 0.01 to 1.96, one study, 87 women); and neonatal mortality (RR 0.89, 95% CI 0.06 to 13.70, one study, 83 women). L-Arginine compared with placebo or no therapy (1 study, 43 women) One study (France) involving 43 pregnant women with FGR was included. This study did not assess our primary outcomes. Nitroglycerin compared to placebo or no therapy (1 studies, 23 women) One study (Brazil) involving 23 pregnant women with FGR was included. We assessed the certainty of the evidence as low. The effect on the primary outcomes is not estimable due to no events in women participating in both groups. Sildenafil citrate compared to nitroglycerin (1 study, 23 women) One study (Brazil) involving 23 pregnant women with FGR was included. We assessed the certainty of the evidence as low. The effect on the primary outcomes is not estimable due to no events in women participating in both groups.

AUTHORS' CONCLUSIONS

Interventions affecting the nitric oxide pathway probably do not seem to influence all-cause (fetal and neonatal) mortality in pregnant women carrying a baby with FGR, although more evidence is needed. The certainty of this evidence is moderate for sildenafil and low for tadalafil and nitroglycerin. For sildenafil a fair amount of data are available from randomised clinical trials, but with low numbers of participants. Therefore, the certainty of evidence is moderate. For the other interventions investigated in this review there are insufficient data, meaning we do not know whether these interventions improve perinatal and maternal outcomes in pregnant women with FGR.

Transcriptomic profiling reveals differential cellular response to copper oxide nanoparticles and polystyrene nanoplastics in perfused human placenta

The growing nanoparticulate pollution (e.g. engineered nanoparticles (NPs) or nanoplastics) has been shown to pose potential threats to human health. In particular, sensitive populations such as pregnant women and their unborn children need to be protected from harmful environmental exposures. However, developmental toxicity from prenatal exposure to pollution particles is not yet well studied despite evidence of particle accumulation in human placenta. Our study aimed to investigate how copper oxide NPs (CuO NPs; 10-20 nm) and polystyrene nanoplastics (PS NPs; 70 nm) impact on gene expression in ex vivo perfused human placental tissue. Whole genome microarray analysis revealed changes in global gene expression profile after 6 h of perfusion with sub-cytotoxic concentrations of CuO (10 µg/mL) and PS NPs (25 µg/mL). Pathway and gene ontology enrichment analysis of the differentially expressed genes suggested that CuO and PS NPs trigger distinct cellular response in placental tissue. While CuO NPs induced pathways related to angiogenesis, protein misfolding and heat shock responses, PS NPs affected the expression of genes related to inflammation and iron homeostasis. The observed effects on protein misfolding, cytokine signaling, and hormones were corroborated by western blot (accumulation of polyubiquitinated proteins) or qPCR analysis. Overall, the results of the present study revealed extensive and material-specific interference of CuO and PS NPs with placental gene expression from a single short-term exposure which deserves increasing attention. In addition, the placenta, which is often neglected in developmental toxicity studies, should be a key focus in the future safety assessment of NPs in pregnancy.

Multiomic signals associated with maternal epidemiological factors contributing to preterm birth in low- and middle-income countries

Preterm birth (PTB) is the leading cause of death in children under five, yet comprehensive studies are hindered by its multiple complex etiologies. Epidemiological associations between PTB and maternal characteristics have been previously described. This work used multiomic profiling and multivariate modeling to investigate the biological signatures of these characteristics. Maternal covariates were collected during pregnancy from 13,841 pregnant women across five sites. Plasma samples from 231 participants were analyzed to generate proteomic, metabolomic, and lipidomic datasets. Machine learning models showed robust performance for the prediction of PTB (AUROC = 0.70), time-to-delivery (r = 0.65), maternal age (r = 0.59), gravidity (r = 0.56), and BMI (r = 0.81). Time-to-delivery biological correlates included fetal-associated proteins (e.g., ALPP, AFP, and PGF) and immune proteins (e.g., PD-L1, CCL28, and LIFR). Maternal age negatively correlated with collagen COL9A1, gravidity with endothelial NOS and inflammatory chemokine CXCL13, and BMI with leptin and structural protein FABP4. These results provide an integrated view of epidemiological factors associated with PTB and identify biological signatures of clinical covariates affecting this disease.

Single-cell RNA-seq reveals developmental deficiencies in both the placentation and the decidualization in women with late-onset preeclampsia

Preeclampsia (PE) is a leading cause of maternal and fetal morbidity and mortality. Although increasing lines of evidence suggest that both the placenta and the decidua likely play roles in the pathogenesis of PE, the molecular mechanism of PE remains elusive partly because of the heterogeneity nature of the maternal-fetal interface. In this study, we perform single-cell RNA-seq on the placenta and the decidual from patients with late-onset PE (LOPE) and women in normal pregnancy. Analyses of single-cell transcriptomes reveal that in LOPE, there are likely a global development deficiency of trophoblasts with impaired invasion of extravillous trophoblasts (EVT) and increased maternal immune rejection and inflammation in the placenta, while there are likely insufficient decidualization of decidual stromal cells (DSC), increased inflammation, and suppressed regulatory functions of decidual immune cells. These findings improve our understanding of the molecular mechanisms of PE.

Dietary supplements and vascular function in hypertensive disorders of pregnancy

Hypertensive disorders of pregnancy are complications that can lead to maternal and infant mortality and morbidity. Hypertensive disorders of pregnancy are generally defined as hypertension and may be accompanied by other end organ damages including proteinuria, maternal organ disturbances including renal insufficiency, neurological complications, thrombocytopenia, impaired liver function, or uteroplacental dysfunction such as fetal growth restriction and stillbirth. Although the causes of these hypertensive disorders of pregnancy are multifactorial and elusive, they seem to share some common vascular-related mechanisms, including diseased spiral arteries, placental ischemia, and endothelial dysfunction. Recently, preeclampsia is being considered as a vascular disorder. Unfortunately, due to the complex etiology of preeclampsia and safety concerns on drug usage during pregnancy, there is still no effective pharmacological treatments available for preeclampsia yet. An emerging area of interest in this research field is the potential beneficial effects of dietary intervention on reducing the risk of preeclampsia. Recent studies have been focused on the association between deficiencies or excesses of some nutrients and complications during pregnancy, fetal growth and development, and later risk of cardiovascular and metabolic diseases in the offspring. In this review, we discuss the involvement of placental vascular dysfunction in preeclampsia. We summarize the current understanding of the association between abnormal placentation and preeclampsia in a vascular perspective. Finally, we evaluate several studied dietary supplementations to prevent and reduce the risk of preeclampsia, targeting placental vascular development and function, leading to improved pregnancy and postnatal outcomes.

Berberine hydrochloride inhibits migration ability via increasing inducible NO synthase and peroxynitrite in HTR-8/SVneo cells

ETHNOPHARMACOLOGICAL RELEVANCE

Inadequate trophoblasts migration and invasion is considered as an initial event resulting in preeclampsia, which is closely related to oxidative stress. Berberine hydrochloride (BBR), extracted from the traditional medicinal plant Coptis chinensis Franch., exerts a diversity of pharmacological effects, and the crude drug has been widely taken by most Chinese women to treat nausea and vomit during pregnancy. But there is no research regarding its effects on trophoblast cell function.

AIM OF THE STUDY

This study aimed to investigate the effect of BBR on human-trophoblast-derived cell line (HTR-8/SVneo) migration ability and its mechanism.

MATERIALS AND METHODS

Cell viability was detected by CCK-8 assay. The effect of BBR on cells migration function was examined by scratch wound healing assay and transwell migration assay. Intracellular nitric oxide (NO), superoxide (O₂^-) and peroxynitrite (ONOO^-) levels were measured by flow cytometry. The expression levels of inducible NO synthase (iNOS), eNOS, p-eNOS, MnSOD, CuZnSOD, Rac1, NOX1, TLR4, nuclear factor-κB (NF-κB), p-NFκB, pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) in cells were analyzed by Western blotting. Uric acid sodium salt (UA), the scavenger of ONOO^-, PEG-SOD (a specific superoxide scavenger), L-NAME (a NOS inhibitor) and antioxidants (Vit E and DFO) were further used to characterize the pathway of BBR action.

RESULTS

5 μM BBR decreased both the migration distance and the number of migrated cells without affecting cells viability in HTR-8/SVneo cells after 24 h treatment. BBR could increase the level of NO in HTR-8/SVneo cells, and the over-production of NO might be attributable to iNOS, but not eNOS. BBR could increase intracellular O₂^- levels, and the over-production of O₂^- is closely related with Rac1 in HTR-8/SVneo cells. The excessive production of NO and O₂^- further react to form ONOO^-, and the increased ONOO^- level induced by BBR was blunted by UA. Moreover, UA improved the impaired migration function caused by BBR in HTR-8/SVneo cells. The depressed migration function stimulated by BBR in HTR-8/SVneo cells was diminished by PEG-SOD and L-NAME. Furthermore, BBR increased the expression of IL-6 in HTR-8/SVneo cells, and antioxidants (Vit E and DFO) could decrease the expression of IL-6 and iNOS induced by BBR.

CONCLUSIONS

BBR inhibits the cell migration ability through increasing inducible NO synthase and peroxynitrite in HTR-8/SVneo cells, indicating that BBR and traditional Chinese medicines containing a high proportion of BBR should be used with caution in pregnant women.

A review of the literature: How does prenatal opioid exposure impact placental health and fetal brain development?

In recent years, there has been a sixfold increase in the number of pregnant people with opioid use disorder (OUD). Rates of neonatal opioid withdrawal syndrome (NOWS), previously known as neonatal abstinence syndrome (NAS), have significantly increased in virtually every state and demographic group (Healthcare Cost Utilization Project, HCUP, 2010). NOWS is a condition resulting from chronic exposure to either therapeutic opioid use (e.g., medication for OUD, chronic pain conditions) or nonprescribed opioid use. To date, there is no known prenatal treatment to help decrease the risk of infants developing NOWS and subsequent neurodevelopmental outcomes. Given the increasing support for how placental signaling, or placental programming, may play a role in downstream pathology, prospective research investigating how the placenta is affected by chronic opioid exposure morphologically, histologically, and at the cellular level may open up potential treatment opportunities in this field. In this review, we discuss literature exploring the physiological roles of nitric oxide and dopamine not only in the vascular development of the placenta, but also in fetal cerebral blood flow, neurogenesis, neuronal differentiation, and neuronal activity. We also discuss histological preclinical studies that suggest chronic opioid exposure to induce some combination of placental dysfunction and hypoxia in a manner similar to other well-known placental pathologies, as denoted by the compensatory neovascularization and increased utilization of the placenta's supply of trophoblast cells, which play an essential role in placental angiogenesis. Overall, we found that the current literature, while limited, suggests chronic opioid exposure negatively impacts placental function and fetal brain development on a cellular and histopathological level. We conclude that it is worthwhile to consider the placenta as a therapeutic target with the ultimate goal of decreasing the incidence of NOWS and the long-term impacts of prenatal opioid exposure.

Imbalance of Angiogenic and Growth Factors in Placenta in Maternal Hyperhomocysteinemia

Numerous studies have shown that various adverse factors of different nature and action mechanisms have similar negative influence on placental angiogenesis, resulting in insufficiency of placental blood supply. One of the risk factors for pregnancy complications with placental etiology is an increased level of homocysteine in the blood of pregnant women. However, the effect of hyperhomocysteinemia (HHcy) on the development of the placenta and, in particular, on the formation of its vascular network is at present poorly understood. The aim of this work was to study the effect of maternal HHcy on the expression of angiogenic and growth factors (VEGF-A, MMP-2, VEGF-B, BDNF, NGF), as well as their receptors (VEGFR-2, TrkB, p75NTR), in the rat placenta. The effects of HHcy were studied in the morphologically and functionally different maternal and fetal parts of the placenta on the 14th and 20th day of pregnancy. The maternal HHcy caused increase in the levels of oxidative stress and apoptosis markers accompanied by an imbalance of the studied angiogenic and growth factors in the maternal and/or fetal part of the placenta. The influence of maternal HHcy in most cases manifested in a decrease in the protein content (VEGF-A), enzymatic activity (MMP-2), gene expression (VEGFB, NGF, TRKB), and accumulation of precursor form (proBDNF) of the investigated factors. In some cases, the effects of HHcy differed depending on the placental part and stage of development. The influence of maternal HHcy on signaling pathways and processes controlled by the studied angiogenic and growth factors could lead to incomplete development of the placental vasculature and decrease in the placental transport, resulting in fetal growth restriction and impaired fetal brain development.

Common pregnancy complications and polyphenols intake: an overview

During pregnancy, the body undergoes a great amount of changes in order to support a healthy developing fetus. In this context, maternal dietary supplementation is widely encouraged to provide adequate nutrition for the newborn. In the past few years, studies have emerged highlighting the benefits of polyphenols intake during pregnancy. Indeed, despite differences among reports, such as experimental model, polyphenol employed, dosage and regimen of administration, there is no doubt that the ingestion of these molecules has a protective effect in relation to three pregnancy-associated diseases or conditions: preeclampsia, gestational diabetes and fetal growth restriction. In this review, we describe the effects of different polyphenols and polyphenol-rich extracts or juices on the main outcomes of these common pregnancy-associated complications, obtained in human, animal and in vitro studies. Therefore, this work provides a critical analysis of the literature, and a summary of evidences, from which future research using polyphenols can be designed and evaluated.

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.

Nitric Oxide Production and Effects in Group B Streptococcus Chorioamnionitis

Intrauterine infection, or chorioamnionitis, due to group B Streptococcus (GBS) is a common cause of miscarriage and preterm birth. To cause chorioamnionitis, GBS must bypass maternal-fetal innate immune defenses including nitric oxide (NO), a microbicidal gas produced by nitric oxide synthases (NOS). This study examined placental NO production and its role in host-pathogen interactions in GBS chorioamnionitis. In a murine model of ascending GBS chorioamnionitis, placental NOS isoform expression quantified by RT-qPCR revealed a four-fold expression increase in inducible NOS, no significant change in expression of endothelial NOS, and decreased expression of neuronal NOS. These NOS expression results were recapitulated ex vivo in freshly collected human placental samples that were co-incubated with GBS. Immunohistochemistry of wild type C57BL/6 murine placentas with GBS chorioamnionitis demonstrated diffuse inducible NOS expression with high-expression foci in the junctional zone and areas of abscess. Pregnancy outcomes between wild type and inducible NOS-deficient mice did not differ significantly although wild type dams had a trend toward more frequent preterm delivery. We also identified possible molecular mechanisms that GBS uses to survive in a NO-rich environment. In vitro exposure of GBS to NO resulted in dose-dependent growth inhibition that varied by serovar. RNA-seq on two GBS strains with distinct NO resistance phenotypes revealed that both GBS strains shared several detoxification pathways that were differentially expressed during NO exposure. These results demonstrate that the placental immune response to GBS chorioamnionitis includes induced NO production and indicate that GBS activates conserved stress pathways in response to NO exposure.

Sildenafil during the 2nd and 3rd Trimester of Pregnancy: Trials and Tribulations

Sildenafil, a phosphodiesterase 5 inhibitor with a vasodilatory and anti-remodeling effect, has been investigated concerning various conditions during pregnancy. Per indication, we herein review the rationale and the most relevant experimental and clinical studies, including systematic reviews and meta-analyses, when available. Indications for using sildenafil during the second and third trimester of pregnancy include maternal pulmonary hypertension, preeclampsia, preterm labor, fetal growth restriction, oligohydramnios, fetal distress, and congenital diaphragmatic hernia. For most indications, the rationale for administering prenatal sildenafil is based on limited, equivocal data from in vitro studies and rodent disease models. Clinical studies report mild maternal side effects and suggest good fetal tolerance and safety depending on the underlying pathology.

Vascular endothelial growth factor and its receptors regulation in gestational diabetes mellitus and eclampsia

Background

An imbalance in the expression of vascular endothelial growth factor (VEGF) and its receptor (VEGF-R) during pregnancy plays an important role in the pathogenesis of gestational diabetes mellitus (GDM) and eclampsia. VEGF and its receptors change during the regulation of blood vessels as a result of risk factors such as familial genetics. These modifications include loss of original balance of serological indicators, upregulation or downregulation of growth factor indicators, and changes in the placenta, kidney, liver and other organs to varying degrees of damage. This has an impact on both the pregnant woman's and the fetus's health.

Main body

This paper summarizes the mechanisms of unbalanced VEGF and receptor expression based on data from relevant literature on GDM and eclampsia. An Imbalance in VEGF and its binding receptor is often associated with the occurrence of multiple pregnancy disorders. In recent years, researchers have focused on the potential role of VEGF and its receptors in the development of GDM and eclampsia.

Conclusion

This paper summarizes the different VEGF subtypes and their binding receptors, as well as mechanisms that cause GDM and eclampsia, in order to provide valuable data to inform monitoring, diagnosis, and prognosis.

Glibenclamide Increases Nitric Oxide Levels and Decreases Oxidative Stress in an In Vitro Model of Preeclampsia

(1) Background: The bioavailability of nitric oxide (NO) and oxidative stress are important events related to the pathophysiology of preeclampsia (PE). In this present study, we aimed to evaluate the antioxidant effect of glibenclamide (GB) on the NO synthesis, oxidative stress, and antioxidant capacity in endothelial cells incubated with plasma from preeclamptic (PE) and normotensive pregnant women (NT). (2) Methods: Human umbilical vein endothelial cells (HUVECs) were incubated with a plasma pool from 10 NT and 10 PE pregnant women; NO/NOx quantification and ROS levels were assessed by a fluorescence compound; lipid peroxidation was evaluated employing thiobarbituric acid (TBA); and total antioxidant capacity was measured by ferric reduction ability power (FRAP) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). (3) Results: We found that endothelial cells incubated with plasma from PE showed lower NO and NOx levels compared with the NT group. However, GB treatment increased these levels, as well as the antioxidant capacity. Furthermore, a decrease was observed in ROS generation and lipid peroxidation (4) Conclusions: The GB treatment exerted a positive effect on the NO/NOx production by HUVEC incubated with plasma from NT and PE pregnant women, as well as in the reduction in oxidative stress and increase in the antioxidant capacity.

Exogenous L-arginine administration improves uterine vascular perfusion, uteroplacental thickness, steroid concentrations, and nitric oxide levels in pregnant buffaloes under subtropical conditions

Heat stress (HS) during pregnancy adversely affects uterine vascular perfusion and fetal development. L-arginine (L-Arg), a nitric oxide (NO) precursor, has been proven to enhance an organ's vascular perfusion. Therefore, this study aimed to examine the effect of L-Arg administration on the pregnant buffaloes' uterine hemodynamics and uteroplacental thickness under environmental HS conditions. For this purpose, pluriparous (n=12) HS-pregnant buffaloes (mid-gestation, 180-190 d; temperature humidity index > 85) were haphazardly assigned into two groups, either administered a single intravenous (IV) bolus of 5 mg/kg BW of L-Arg Hcl (n=6; ARG) or received normal saline (0.9%; IV; 25 ml) that served as a control group (n=6; CON). Combined uteroplacental thickness (CUPT, mm), middle uterine arteries' (MUA) diameter (mm), and uterine Doppler hemodynamics (ipsi-lateral and contralateral to the pregnant horn) were examined utilizing B-mode and color Doppler ultrasonography, respectively. The serum levels of progesterone (P4), estradiol 17 β (E2), nitric oxide (NO), and total antioxidant capacity (TAC) were assayed using commercial kits. The experimental time points were -1, 0, 2, 4, 24, 48, 72, 96, and 120 h post-L-Arg administration. The ARG group showed higher (P < 0.05) CUPT and MUA diameter values starting at 24 h post-treatment and onward than the control buffalo cows. In addition, there were improvements (P<0.05) in the blood flow parameters in the ipsilateral MUA after L-Arg treatment evidenced by lower values of pulsatility and resistive indices starting at 48 and 4 h, respectively and onward, and higher values of peak systolic velocity, colored areas toward the pregnant uterine horn (both 24-72 h). Increases in the NO levels were found during the period between 4 and 120 h in the ARG group compared to the CON group. Moreover, significant increases in the E2 and P4 means were noted in the ARG group, especially at 24 h onward, respectively compared to the CON group. Concerning the TAC status, neither the administration nor the hours affected serum TAC levels in the HS pregnant buffaloes (CON and ARG). In conclusion, L-Arg administration improved uteroplacental thickness and enhanced uterine hemodynamics, NO levels, and steroids production in mid-pregnant buffalo cows under environmental heat stress conditions which could improve fetal growth and development.

Low-Dose Tacrolimus Promotes the Migration and Invasion and Nitric Oxide Production in the Human-Derived First Trimester Extravillous Trophoblast Cells In Vitro

Placentation is one of the most important determinants for a successful pregnancy, and this is dependent on the process of trophoblast migration and invasion. Progesterone receptors (PGR) are critical effectors of progesterone (P4) signaling that is required for trophoblast migration and invasion conducive to a successful gestation. In immune complicated pregnancies, evidence has shown that abnormal placentation occurs because of aberrant expression of PGR. Therapeutic intervention with tacrolimus (FK506) was able to restore PGR expression and improve pregnancy outcomes in immune-complicated gestations; however, the exact mode of action of tacrolimus in assisting placentation is not clear. Here, we attempt to uncover the mode of action of tacrolimus by examining its effects on trophoblast invasion and migration in the human-derived extravillous trophoblast (EVT) cell line, the HTR-8/SVneo cells. Using a variety of functional assays, we demonstrated that low-dose tacrolimus (10 ng/mL) was sufficient to significantly (p < 0.001) stimulate the migration and invasion of the HTR-8/SVneo cells, inducing their cytosolic/nuclear progesterone receptor expression and activation, and modulating their Nitric Oxide (NO) production. Moreover, tacrolimus abrogated the suppressive effect of the NOS inhibitor Nω- Nitro-L-Arginine Methyl Ester (L-NAME) on these vital processes critically involved in the establishment of human pregnancy. Collectively, our data suggest an immune-independent mode of action of tacrolimus in positively influencing placentation in complicated gestations, at least in part, through promoting the migration and invasion of the first trimester extravillous trophoblast cells by modulating their NO production and activating their cytosolic/nuclear progesterone-receptors. To our knowledge, this is the first report to show that the mode of action of tacrolimus as a monotherapy for implantation failure is plausibly PGR-dependent.

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.

Tianma Gouteng Decoction Exerts Pregnancy-Protective Effects Against Preeclampsia via Regulation of Oxidative Stress and NO Signaling

Preeclampsia (PE), a pregnancy-specific syndrome with the major molecular determinants of placenta-borne oxidative stress and consequently impaired nitric oxide (NO) generation, has been considered to be one of the leading causes of maternal morbidity as well as mortality and preterm delivery worldwide. Several medical conditions have been found to be associated with increased PE risk, however, the treatment of PE remains unclear. Here, we report that Tianma Gouteng Decoction (TGD), which is used clinically for hypertension treatment, regulates oxidative stress and NO production in human extravillous trophoblast-derived TEV-1 cells. In human preeclamptic placental explants, reactive oxygen species (ROS) levels were elevated and NO production was inhibited, while TGD treatment at different periods effectively down-regulated the H₂O₂-induced ROS levels and significantly up-regulated the H₂O₂-suppressed NO production in human TEV-1 cells. Mechanistically, TGD enhanced the activity of total nitric oxide synthase (TNOS), which catalyze L-arginine oxidation into NO, and simultaneously, TGD promoted the expression of neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS), two isoforms of nitric oxide synthetases (NOS) in human placenta, resulting in the increased NO generation. More importantly, TGD administration not only increased the weight gain during pregnancy and revealed a hypotensive effect, but also improved the placental weight gain and attenuated fetal growth restriction in an NG-nitro-L-arginine methyl ester (L-NAME)-induced mouse PE-like model. Our results thereby provide new insights into the role of TGD as a potentially novel treatment for PE.

The Role of Nitric Oxide in Stem Cell Biology

Nitric oxide (NO) is a gaseous biomolecule endogenously synthesized with an essential role in embryonic development and several physiological functions, such as regulating mitochondrial respiration and modulation of the immune response. The dual role of NO in embryonic stem cells (ESCs) has been previously reported, preserving pluripotency and cell survival or inducing differentiation with a dose-dependent pattern. In this line, high doses of NO have been used in vitro cultures to induce focused differentiation toward different cell lineages being a key molecule in the regenerative medicine field. Moreover, optimal conditions to promote pluripotency in vitro are essential for their use in advanced therapies. In this sense, the molecular mechanisms underlying stemness regulation by NO have been studied intensively over the current years. Recently, we have reported the role of low NO as a hypoxia-like inducer in pluripotent stem cells (PSCs), which supports using this molecule to maintain pluripotency under normoxic conditions. In this review, we stress the role of NO levels on stem cells (SCs) fate as a new approach for potential cell therapy strategies. Furthermore, we highlight the recent uses of NO in regenerative medicine due to their properties regulating SCs biology.

A review of the amino acid metabolism in placental function response to fetal loss and low birth weight in pigs

The fertility of sows mainly depends on the embryo losses during gestation and the survival rate of the post-farrowing piglets. The selection of highly-prolific sows has been mainly focused on the selection of genotypes with high ovulatory quota. However, in the early- and post-implantation stages, the rate of embryo losses was increased with the increase of zygotes. Among the various factors, placental growth and development is the vital determinant for fetal survival, growth, and development. Despite the potential survival of fetuses with deficient placental development, their life-conditions and growth can be damaged by a process termed intrauterine growth retardation (IUGR). The newborn piglets affected by IUGR are prone to increased morbidity and mortality rates; meanwhile, the growth, health and welfare of the surviving piglets will remain hampered by these conditions, with a tendency to exacerbate with age. Functional amino acids such as glycine, proline, and arginine continue to increase with the development of placenta, which are not only essential to placental growth (including vascular growth) and development, but can also be used as substrates for the production of glutathione, polyamines and nitric oxide to benefit placental function in many ways. However, the exact regulation mechanism of these amino acids in placental function has not yet been clarified. In this review, we provide evidence from literature and our own work for the role and mechanism of dietary functional amino acids during pregnancy in regulating the placental functional response to fetal loss and birth weight of piglets. This review will provide novel insights into the response of nutritionally nonessential amino acids (glycine and proline) to placental development as well as feasible strategies to enhance the fertility of sows.

Early Abnormal Placentation and Evidence of Vascular Endothelial Growth Factor System Dysregulation at the Feto-Maternal Interface After Periconceptional Alcohol Consumption

Adequate placentation, placental tissue remodeling and vascularization is essential for the success of gestation and optimal fetal growth. Recently, it was suggested that abnormal placenta induced by maternal alcohol consumption may participate in fetal growth restriction and relevant clinical manifestations of the Fetal Alcohol Spectrum Disorders (FASD). Particularly, periconceptional alcohol consumption up to early gestation can alter placentation and angiogenesis that persists in pregnancy beyond the exposure period. Experimental evidence suggests that abnormal placenta following maternal alcohol intake is associated with insufficient vascularization and defective trophoblast development, growth and function in early gestation. Accumulated data indicate that impaired vascular endothelial growth factor (VEGF) system, including their downstream effectors, the nitric oxide (NO) and metalloproteinases (MMPs), is a pivotal spatio-temporal altered mechanism underlying the early placental vascular alterations induced by maternal alcohol consumption. In this review we propose that the periconceptional alcohol intake up to early organogenesis (first trimester) alters the VEGF-NO-MMPs system in trophoblastic-decidual tissues, generating imbalances in the trophoblastic proliferation/apoptosis, insufficient trophoblastic development, differentiation and migration, deficient labyrinthine vascularization, and uncompleted remodelation and transformation of decidual spiral arterioles. Consequently, abnormal placenta with insufficiency blood perfusion, vasoconstriction and reduced labyrinthine blood exchange can be generated. Herein, we review emerging knowledge of abnormal placenta linked to pregnancy complications and FASD produced by gestational alcohol ingestion and provide evidence of the early abnormal placental angiogenesis-vascularization and growth associated to decidual-trophoblastic dysregulation of VEGF system after periconceptional alcohol consumption up to mid-gestation, in a mouse model.

Comparison of Diagnostic Values of Maternal Arginine Concentration for Different Pregnancy Complications: A Systematic Review and Meta-Analysis

Abnormal arginine metabolism contributes to the development of intrauterine growth restriction (IUGR), preeclampsia (PE), and gestational diabetes mellitus (GDM), which increase the health burden of mothers and induce adverse birth outcomes. However, associations between maternal arginine concentration and different pregnancy complications have not been systematically compared. The PubMed, ScienceDirect, and Web of Science databases were searched for peer-reviewed publications to evaluate the diagnostic value of plasma arginine concentration in complicated pregnancies. Standardized mean difference (SMD) of the arginine concentration was pooled by a random effects model. The results show that increased maternal arginine concentrations were observed in IUGR (SMD: 0.48; 95% CI: 0.20, 0.76; I² = 47.0%) and GDM (SMD: 0.46; 95% CI: 0.11, 0.81; I² = 82.3%) cases but not in PE patients (SMD: 0.21; 95% CI: −0.04, 0.47; I² = 80.3%) compared with the normal cohorts. Subgroup analyses indicated that the non-fasting circulating arginine concentration in third trimester was increased significantly in GDM and severe IUGR pregnancies, but the change mode was dependent on ethnicity. Additionally, only severe PE persons were accompanied by higher plasma arginine concentrations. These findings suggest that maternal arginine concentration is an important reference for assessing the development of pregnancy complications.

L-citrulline ameliorates pathophysiology in a rat model of superimposed preeclampsia

BACKGROUND AND PURPOSE

Preeclampsia, characterized by hypertension, proteinuria, and fetal growth restriction, is one of the leading causes of maternal and perinatal mortality. By far, there is no effective pharmacological therapy for preeclampsia. The present study was conducted to investigate the effects of L-citrulline supplementation in Dahl salt-sensitive rat, a model of superimposed preeclampsia.

EXPERIMENTAL APPROACH

Parental DSSR were treated with L-citrulline (2.5 g/L in drinking water) from the day of mating to the end of lactation period. Blood pressure of the rats was monitored throughout pregnancy and markers of preeclampsia were assessed. Endothelial function of the pregnant DSSR was assessed by wire myograph.

KEY RESULTS

L-citrulline supplementation significantly reduced maternal blood pressure, proteinuria, and levels of circulating soluble fms-like tyrosine kinase 1 in DSSR. L-citrulline improved maternal endothelial function by augmenting the production of nitric oxide in the aorta and improving endothelium-derived hyperpolarizing factor-mediated vasorelaxation in resistance arteries. L-citrulline supplementation improved placental insufficiency and fetal growth, which were associated with an enhancement of angiogenesis and reduction of fibrosis and senescence in the placentas. In addition, L-citrulline downregulated genes involved in the toll-like receptor 4 and nuclear factor-κB signaling pathway.

CONCLUSION AND IMPLICATIONS

This study shows that L-citrulline supplementation reduces gestational hypertension, improves placentation and fetal growth in a rat model of superimposed preeclampsia. L-citrulline supplementation may represent an effective and safe therapeutic strategy for preeclampsia that benefit both the mother and the fetus.

Endothelial Dysfunction in Pregnancy Complications

The endothelium, which constitutes the inner layer of blood vessels and lymphatic structures, plays an important role in various physiological functions. Alterations in structure, integrity and function of the endothelial layer during pregnancy have been associated with numerous gestational complications, including clinically significant disorders, such as preeclampsia, fetal growth restriction, and diabetes. While numerous experimental studies have focused on establishing the role of endothelial dysfunction in pathophysiology of these gestational complications, their mechanisms remain unknown. Numerous biomarkers of endothelial dysfunction have been proposed, together with the mechanisms by which they relate to individual gestational complications. However, more studies are required to determine clinically relevant markers specific to a gestational complication of interest, as currently most of them present a significant overlap. Although the independent diagnostic value of such markers remains to be insufficient for implementation in standard clinical practice at the moment, inclusion of certain markers in predictive multifactorial models can improve their prognostic value. The future of the research in this field lies in the fine tuning of the clinical markers to be used, as well as identifying possible therapeutic techniques to prevent or reverse endothelial damage.

Malaria in Pregnancy: From Placental Infection to Its Abnormal Development and Damage

Malaria remains a global health burden with Plasmodium falciparum accounting for the highest mortality and morbidity. Malaria in pregnancy can lead to the development of placental malaria, where P. falciparum-infected erythrocytes adhere to placental receptors, triggering placental inflammation and subsequent damage, causing harm to both mother and her infant. Histopathological studies of P. falciparum-infected placentas revealed various placental abnormalities such as excessive perivillous fibrinoid deposits, breakdown of syncytiotrophoblast integrity, trophoblast basal lamina thickening, increased syncytial knotting, and accumulation of mononuclear immune cells within intervillous spaces. These events in turn, are likely to impair placental development and function, ultimately causing placental insufficiency, intrauterine growth restriction, preterm delivery and low birth weight. Hence, a better understanding of the mechanisms behind placental alterations and damage during placental malaria is needed for the design of effective interventions. In this review, using evidence from human studies and murine models, an integrated view on the potential mechanisms underlying placental pathologies in malaria in pregnancy is provided. The molecular, immunological and metabolic changes in infected placentas that reflect their responses to the parasitic infection and injury are discussed. Finally, potential models that can be used by researchers to improve our understanding on the pathogenesis of malaria in pregnancy and placental pathologies are presented.

Temporal dynamics of nitric oxide wave in early vasculogenesis

Endothelium-derived nitric oxide (NO) is a mediator of angiogenesis. However, NO-mediated regulation of vasculogenesis remains largely unknown. In the present study, we show that the inhibition of NO significantly attenuated endothelial migration, ring formation, and tube formation. The contribution of nitric oxide synthase (NOS) enzymes during early vasculogenesis was assessed by evaluating endothelial NOS (eNOS) and inducible NOS (iNOS) mRNA expression during HH10-HH13 stages of chick embryo development. iNOS but not eNOS was expressed at HH12 and HH13 stages. We hypothesized that vasculogenic events are controlled by NOS-independent reduction of nitrite to NO under hypoxia during the very early phases of development. Semi-quantitative polymerase chain reaction analysis of hypoxia-inducible factor-1α (HIF-1α) showed higher expression at HH10 stage, after which a decrease was observed. This observation was in correlation with the nitrite reductase (NR) activity at HH10 stage. We observed a sodium nitrite-induced increase in NO levels at HH10, reaching a gradual decrease at HH13. The possible involvement of a HIF/NF-κB/iNOS signaling pathway in the process of early vasculogenesis is suggested by the inverse relationship observed between nitrite reduction and NOS activation between HH10 and HH13 stages. Further, we detected that NR-mediated NO production was inhibited by several NR inhibitors at the HH10 stage, whereas the inhibitors eventually became less effective at later stages. These findings suggest that the temporal dynamics of the NO source switches from NR to NOS in the extraembryonic area vasculosa, where both nitrite reduction and NOS activity are defined by hypoxia.

A meta-analysis for association of eNOS VNTR 4b/a, - 786 T > C and + 894G > T polymorphisms with risk of recurrent pregnancy loss

BACKGROUND

The association of polymorphisms at nitric oxide synthases (eNOS) gene with recurrent pregnancy loss (RPL) susceptibility has been the focus of attention in several studies. However, the conclusions have been divergent and controversial. Therefore, we performed this study to precisely evaluate the association of eNOS polymorphisms with the risk of RPL.

METHODS

A universal search in PubMed, Web of Knowledge, SciELO, MedRxiv, Scopus and web of Science was performed to identify relevant studies up to January 25, 2020.

RESULTS

A total of 39 eligible studies including 15 studies with 2274 cases and 1933 controls on VNTR 4b/a, nine studies with 1640 cases and 1268 controls on -786C > T, and 15 studies with 2660 cases and 2557 controls on + 894G > T polymorphism were selected. Pooled data revealed that eNOS VNTR 4b/a (dominant model: OR = 1.174, 95% CI 1.021-1.350, p = 0.025) and + 894G > T (allele model: OR = 1.278, 95% CI 1.024-1.595, p = 0.030; homozygote model: OR = 1.442, 95% CI 1.084-1.917, p = 0.012; dominant model: OR = 1.305, 95% CI 1.006-1.693, p = 0.045; and recessive model: OR = 1.378, 95% CI 1.045-1.817, p = 0.023) polymorphisms were significantly associated with an increased risk of RPL, but not  - 786 T > C. Stratified analysis by ethnicity revealed that the eNOS + 894G > T was associated with RPL risk in Asians.

CONCLUSIONS

To sum up, our results indicated that the eNOS VNTR 4b/a and + 894G > T polymorphisms might be contributing to RPL development, but not the  - 786C > T polymorphism.

The metabolic landscape of decidua in recurrent pregnancy loss using a global metabolomics approach

INTRODUCTION

Maternal metabolism undergoes dynamic changes during pregnancy. A deviation from this physiological metabolic status might be involved in the pathogenesis of pregnancy complications, such as recurrent pregnancy loss (RPL). Decidua is an important uterine tissue, which provides immunological protection as well as nutritional support to the developing embryo during early pregnancy. Previous studies have shown that aberrant metabolism of the decidua is related to the etiology of RPL. However, the metabolic profile of the decidua in RPL has not yet been fully elucidated.

METHODS

In the current study, decidual samples from RPL patients (n = 23) and normal pregnancy (NP) women (n = 30) were collected, and hydrophilic and hydrophobic metabolites were extracted and measured using a liquid chromatography electrospray ionization tandem mass spectrometry system. Besides, the mRNA expression of several critical enzymes involved in sphingolipid metabolism and glycerophospholipid metabolism was detected.

RESULTS

The OSC-PLS-DA scores plot illustrates that metabolic differences are present in the decidual tissue of RPL patients compared with that of NP women. Combining multivariate analysis with univariate statistical analysis, a total of 62 metabolites related to RPL were selected, including carnitine, glycerophospholipids, sphingomyelin (SM), ceramide, organic acids and their derivatives, and amino acid metabolomics. KEGG analysis showed that abnormalities in multiple metabolic pathways occurred in RPL decidua, including vitamin digestion and absorption, tryptophan metabolism, citrate cycle, arginine biosynthesis, glycerophospholipid metabolism, sphingolipid metabolism, and sphingolipid signaling pathway. Increased SM synthase and decreased Phospholipase A2 Group IIE mRNA levels were detected in RPL compared with NP group.

DISCUSSION

Disruption of decidual metabolism, especially glycerophospholipid metabolism and sphingolipid metabolism, might be involved in the occurrence of RPL.

Placental Angiogenesis in Mammals: A Review of the Regulatory Effects of Signaling Pathways and Functional Nutrients

Normal placental development and proper angiogenesis are essential for fetal growth during pregnancy. Angiogenesis involves the regulatory action of many angiogenic factors and a series of signal transduction processes inside and outside the cell. The obstruction of placental angiogenesis causes fetal growth restriction and serious pregnancy complications, even leading to fetal loss and pregnancy cessation. In this review, the effects of placental angiogenesis on fetal development are described, and several signaling pathways related to placental angiogenesis and their key regulatory mediators are summarized. These factors, which include vascular endothelial growth factor (VEGF)-VEGF receptor, delta-like ligand 4 (DLL-4)-Notch, Wnt, and Hedgehog, may affect the placental angiogenesis process. Moreover, the degree of vascularization depends on cell proliferation, migration, and differentiation, which is affected by the synthesis and secretion of metabolites or intermediates and mutual coordination or inhibition in these pathways. Furthermore, we discuss recent advances regarding the role of functional nutrients (including amino acids and fatty acids) in regulating placental angiogenesis. Understanding the specific mechanism of placental angiogenesis and its influence on fetal development may facilitate the establishment of new therapeutic strategies for the treatment of preterm birth, pre-eclampsia, or intrauterine growth restriction, and provide a theoretical basis for formulating nutritional regulation strategies during pregnancy.

Novel insights for the role of nitric oxide in placental vascular function during and beyond pregnancy

More than 30 years have passed since endothelial nitric oxide synthesis was described using the umbilical artery and vein endothelium. That seminal report set the cornerstone for unveiling the molecular aspects of endothelial function. In parallel, the understanding of placental physiology has gained growing interest, due to its crucial role in intrauterine development, with considerable long-term health consequences. This review discusses the evidence for nitric oxide (NO) as a critical player of placental development and function, with a special focus on endothelial nitric oxide synthase (eNOS) vascular effects. Also, the regulation of eNOS-dependent vascular responses in normal pregnancy and pregnancy-related diseases and their impact on prenatal and postnatal vascular health are discussed. Recent and compelling evidence has reinforced that eNOS regulation results from a complex network of processes, with novel data concerning mechanisms such as mechano-sensing, epigenetic, posttranslational modifications, and the expression of NO- and l-arginine-related pathways. In this regard, most of these mechanisms are expressed in an arterial-venous-specific manner and reflect traits of the fetal systemic circulation. Several studies using umbilical endothelial cells are not aimed to understand placental function but general endothelial function, reinforcing the influence of the placenta on general knowledge in physiology.

The Role of Oxidative Stress in Hypertensive Disorders of Pregnancy (Preeclampsia, Gestational Hypertension) and Metabolic Disorder of Pregnancy (Gestational Diabetes Mellitus)

Purpose of the Review.To highlight the role of oxidative stress in hypertensive disorders of pregnancy (HDP) and metabolic disorders of pregnancy (gestational diabetes mellitus). Recent Findings. In both preeclampsia (PE) and gestational hypertension (GH), oxidative stress leads to inadequate placental perfusion thus resulting in a hypoxic placenta, which generally leads to the activation of maternal systemic inflammatory response. In PE, this causes inflammation in the kidneys and leads to proteinuria. A proteinuria marker known as urinary 8-oxoGuo excretion is expressed in preeclampsia. In GDM, oxidative stress plays a role in the pathogenesis of the disease, as a result of over secretion of insulin during pregnancy. This uncontrolled secretion of insulin results in the production of lipid peroxidation factors that also mask the secretion of antioxidants. Therefore, ROS becomes abundant at cellular level and prevents the cells from transporting glucose to body tissues. Summary. There is a need for more research investigating the role of oxidative stress, especially in obstetrics-related conditions. More studies are required in order to understand the difference between the pathogenesis and pathophysiology of PE versus GH since investigations on the differences in genetic aspects of each condition are lacking. Furthermore, research to improve diagnostic procedures for GDM in pregnancy is needed.

Effects of vitamin D-induced supernatant of placental explants from preeclamptic women on oxidative stress and nitric oxide bioavailability in human umbilical vein endothelial cells

The study evaluated the effect of the supernatant of placental explants from preeclamptic (PE) and normotensive (NT) pregnant women after tissue treatment with or without vitamin D (VD) on oxidative stress and nitric oxide (NO) bioavailability in human umbilical vein endothelial cells (HUVEC). Placental explants were prepared from eight NT and eight PE women, and supernatants were obtained after incubation with or without hydrogen peroxide (H₂O₂) and/or VD. HUVEC were cultured for 24 h with supernatants, and the following parameters were analyzed in HUVEC cultures: NO, nitrate (NO₃^-), and nitrite (NO₂^-) levels, lipid peroxidation, and intracellular reactive oxygen species (ROS). Results showed that the production of NO₃^-, NO₂^-, malondialdehyde (MDA), and ROS were significantly higher in HUVEC treated with explant supernatant from PE compared to NT pregnant women, while the supernatant of PE explants treated with VD led to a decrease in these parameters. A significantly high production of NO was detected in HUVEC cultured with control supernatant of NT group, and in cultures treated with supernatant of PE explants treated with VD. Taken together, these results demonstrated that cultures of placental explants from PE women with VD treatment generated a supernatant that decreased oxidative stress and increased the bioavailability of NO in endothelial cells.

Prenatal anemia and postpartum hemorrhage risk: A systematic review and meta-analysis

INTRODUCTION

Postpartum hemorrhage (PPH) has remained the leading cause of maternal mortality. While anemia is a leading contributor to maternal morbidity, molecular, cellular and anemia-induced hypoxia, clinical studies of the relationship between prenatal-anemia and PPH have reported conflicting results. Therefore, our objective was to investigate the outcomes of studies on the relationships between prenatal anemia and PPH-related mortality.

MATERIALS AND METHODS

Electronic databases (MEDLINE, Scopus, ClinicalTrials.gov, PROSPERO, EMBASE, and the Cochrane Central Register of Controlled Trials) were searched for studies published before August 2019. Keywords included "anemia," "hemoglobin," "postpartum hemorrhage," and "postpartum bleeding." Only studies involving the association between anemia and PPH were included in the meta-analysis. Our primary analysis used random effects models to synthesize odds-ratios (ORs) extracted from the studies. Heterogeneity was formally assessed with the Higgins' I² statistics, and explored using meta-regression and subgroup analysis.

RESULTS

We found 13 eligible studies investigating the relationship between prenatal anemia and PPH. Our findings suggest that severe prenatal anemia increases PPH risk (OR = 3.54; 95% CI: 1.20, 10.4, p-value = 0.020). There was no statistical association with mild (OR = 0.60; 95% CI: 0.31, 1.17, p-value = 0.130), or moderate anemia (OR = 2.09; 95% CI: 0.40, 11.1, p-value = 0.390) and the risk of PPH.

CONCLUSION

Severe prenatal anemia is an important predictive factor of adverse outcomes, warranting intensive management during pregnancy. PROSPERO Registration Number: CRD42020149184; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=149184.

Salvianic Acid A Regulates High-Glucose-Treated Endothelial Progenitor Cell Dysfunction via the AKT/Endothelial Nitric Oxide Synthase (eNOS) Pathway

BACKGROUND The primary cause of death in patients with diabetes mellitus (DM) is diabetic macroangiopathy, a complication that related to the function and number of endothelial progenitor cells (EPCs). Salvianic acid A (SAA) is a water-soluble active ingredient of Salvia miltiorrhiza, a traditional Chinese medicine used to treat cardiovascular diseases. The purpose of this study was to explore the effects of SAA on the function of rat EPCs cultured in vitro in a high-glucose environment. MATERIAL AND METHODS Bone marrow-derived EPCs from 40 Sprague-Dawley rats were identified by fluorescence staining. Cell viability, apoptosis, tube formation, lactated dehydrogenase (LDH) release, and nitric oxide (NO) production were detected by 3-[4,5-dimethylthylthiazol-2-yl]-2,5 diphenyltetrazolium bromide assay, flow cytometry, tube formation, LDH, and 3-amino,4-aminomethyl-2',7'-difluorescein, and diacetate assays, respectively. The expression levels of proteins were examined by western blotting. RESULTS Cultured EPCs showed a cobblestone morphology and positive expression of Dil-ac-LDL and FITC-UEA-1. High glucose impaired cell viability. Different concentrations of SAA had no significant effect on EPC viability. SAA reduced the apoptosis rate and LDH release, but promoted tube formation, viability, and NO production in high-glucose-treated EPCs. The ratios of p-AKT/AKT and p-eNOS/eNOS in high-glucose-treated EPCs were elevated by SAA. Phosphoinositide 3-kinase inhibitor LY294002 blocked the rescue effects of SAA on high-glucose-treated EPCs. CONCLUSIONS SAA protected EPCs against high-glucose-induced dysfunction via the AKT/eNOS pathway.

Poor Birth Outcomes in Malaria in Pregnancy: Recent Insights Into Mechanisms and Prevention Approaches

Pregnant women in malaria-endemic regions are susceptible to malaria in pregnancy, which has adverse consequences on birth outcomes, including having small for gestational age and preterm babies. These babies are likely to have low birthweights, which predisposes to infant mortality and lifelong morbidities. During malaria in pregnancy, Plasmodium falciparum-infected erythrocytes express a unique variant surface antigen, VAR2CSA, that mediates sequestration in the placenta. This process may initiate a range of host responses that contribute to placental inflammation and dysregulated placental development, which affects placental vasculogenesis, angiogenesis and nutrient transport. Collectively, these result in the impairment of placental functions, affecting fetal development. In this review, we provide an overview of malaria in pregnancy and the different pathological pathways leading to malaria in pregnancy-associated low birthweight. We also discuss current prevention and management strategies for malaria in pregnancy, and some potential therapeutic interventions that may improve birth outcomes. Lastly, we outline some priorities for future research that could bring us one step closer to reducing this health burden.

Dexamethasone-induced intrauterine growth restriction modulates expression of placental vascular growth factors and fetal and placental growth

Prenatal exposure to glucocorticoids (GC) is a central topic of interest in medicine since GCs are essential for the maturation of fetal organs and intrauterine growth. Synthetic glucocorticoids, which are used in obstetric practice, exert beneficial effects on the fetus, but have also been reported to lead to intrauterine growth retardation (IUGR). In this study, a model of growth restriction in mice was established through maternal administration of dexamethasone during late gestation. We hypothesised that GC overexposure may adversely affect placental angiogenesis and fetal and placental growth. Female BALB/c mice were randomly assigned to control or dexamethasone treatment, either left to give birth or euthanised on days 15, 16, 17 and 18 of gestation followed by collection of maternal and fetal tissue. The IUGR rate increased to 100% in the dexamethasone group (8 mg/kg body weight on gestational days 14 and 15) and pups had clinical features of symmetrical IUGR at birth. Dexamethasone administration significantly decreased maternal body weight gain and serum corticosterone levels. Moreover, prenatal dexamethasone treatment not only induced fetal growth retardation but also decreased placental weight. In IUGR placentas, VEGFA protein levels and mRNA expression of VEGF receptors were reduced and NOS activity was lower. Maternal dexamethasone administration also reduced placental expression of the GC receptor, αGR. We demonstrated that maternal dexamethasone administration causes fetal and placental growth restriction. Furthermore, we propose that the growth retardation induced by prenatal GC overexposure may be caused, at least partially, by an altered placental angiogenic profile.

Maternal tadalafil therapy for fetal growth restriction prevents non-alcoholic fatty liver disease and adipocyte hypertrophy in the offspring

We aimed to investigate the effects of maternal tadalafil therapy on fetal programming of metabolic function in a mouse model of fetal growth restriction (FGR). Pregnant C57BL6 mice were divided into the control, L-NG-nitroarginine methyl ester (L-NAME), and tadalafil + L-NAME groups. Six weeks after birth, the male pups in each group were given a high-fat diet. A glucose tolerance test (GTT) was performed at 15 weeks and the pups were euthanized at 20 weeks. We then assessed the histological changes in the liver and adipose tissue, and the adipocytokine production. We found that the non-alcoholic fatty liver disease activity score was higher in the L-NAME group than in the control group (p < 0.05). Although the M1 macrophage numbers were significantly higher in the L-NAME/high-fat diet group (p < 0.001), maternal tadalafil administration prevented this change. Moreover, the epididymal adipocyte size was significantly larger in the L-NAME group than in the control group. This was also improved by maternal tadalafil administration (p < 0.05). Further, we found that resistin levels were significantly lower in the L-NAME group compared to the control group (p < 0.05). The combination of exposure to maternal L-NAME and a high-fat diet induced glucose impairment and non-alcoholic fatty liver disease. However, maternal tadalafil administration prevented these complications. Thus, deleterious fetal programming caused by FGR might be modified by in utero intervention with tadalafil.

The effects of maternal nutrition during the first 50 d of gestation on the location and abundance of hexose and cationic amino acid transporters in beef heifer uteroplacental tissues

We hypothesized that maternal nutrition during the first 50 d of gestation would influence the abundance of hexose transporters, SLC2A1, SLC2A3, and SLC2A5, and cationic amino acid transporters, SLC7A1 and SLC7A2, in heifer uteroplacental tissues. Angus-cross heifers (n = 43) were estrus synchronized, bred via artificial insemination, and assigned at breeding to 1 of 2 dietary intake groups (CON = 100% of requirements to achieve 0.45 kg/d of BW gain or RES = 60% of CON intake) and ovariohysterectomized on day 16, 34, or 50 of gestation (n = 6 to 9/d) in a completely randomized design with a 2 × 3 factorial arrangement of treatments. Uterine cross-sections were collected from the horn ipsilateral to the corpus luteum, fixed in 10% neutral buffered formalin, sectioned at 5 µm, and stained via immunofluorescence for transporters. For each image, areas of fetal membrane (FM; chorioallantois), luminal epithelium (ENDO), superficial glands (SG), deep glands (DG), and myometrium (MYO) were analyzed separately for relative intensity of fluorescence as an indicator of transporter abundance. Analysis of FM was only conducted for days 34 and 50. No transporters in target areas were influenced by a day × treatment interaction (P ≥ 0.06). In ENDO, all transporters were differentially abundant from days 16 to 50 of gestation (P ≤ 0.04), and SLC7A2 was greater (P = 0.05) for RES vs. CON. In SG, SLC7A1 and SLC7A2 were greater (P ≤ 0.04) at day 34 vs. day 16. In DG, SLC2A3 and SLC7A1 were greater (P ≤ 0.05) for CON vs. RES heifers; furthermore, SLC7A1 was greater (P < 0.01) at day 50 vs. days 16 and 34 of gestation. In MYO, SLC7A1 was greater (P < 0.01) for CON vs. RES and was greater (P = 0.02) at days 34 and 50 vs. day 16. There were no differences in FM (P ≥ 0.06). Analysis of all uterine tissues at day 16 determined that SLC2A1, SLC2A3, and SLC7A2 were all differentially abundant across uterine tissue type (P < 0.01), and SLC7A1 was greater (P = 0.02) for CON vs. RES. Analysis of all uteroplacental tissues at days 34 and 50 demonstrated that all transporters differed (P < 0.01) across uteroplacental tissues, and SLC7A1 was greater (P < 0.01) for CON vs. RES. These data are interpreted to imply that transporters are differentially affected by day of gestation, and that hexose and cationic amino acid transporters are differentially abundant across utero-placental tissue types, and that SLC7A1 is responsive to maternal nutritional treatment.