Proliferation of endogenous regulatory T cells improve the pathophysiology associated with placental ischaemia of pregnancy

Reduced uterine perfusion pressure as a model for preeclampsia and fetal growth restriction in murine: a systematic review and meta-analysis

The reduced uterine perfusion pressure (RUPP) model is frequently used to study preeclampsia and fetal growth restriction. An improved understanding of influential factors might improve reproducibility and reduce animal use considering the variability in RUPP phenotype. We performed a systematic review and meta-analysis by searching Medline and Embase (until 28 March, 2023) for RUPP studies in murine. Primary outcomes included maternal blood pressure (BP) or proteinuria, fetal weight or crown-rump length, fetal reabsorptions, or antiangiogenic factors. We aimed to identify influential factors by meta-regression analysis. We included 155 studies. Our meta-analysis showed that the RUPP procedure results in significantly higher BP (MD = 24.1 mmHg; [22.6; 25.7]; n = 148), proteinuria (SMD = 2.3; [0.9; 3.8]; n = 28), fetal reabsorptions (MD = 50.4%; [45.5; 55.2]; n = 42), circulating soluble FMS-like tyrosine kinase-1 (sFlt-1) (SMD = 2.6; [1.7; 3.4]; n = 34), and lower fetal weight (MD = -0.4 g; [-0.47; -0.34]; n = 113. The heterogeneity (variability between studies) in primary outcomes appeared ≥90%. Our meta-regression identified influential factors in the method and time point of BP measurement, randomization in fetal weight, and type of control group in sFlt-1. The RUPP is a robust model considering the evident differences in maternal and fetal outcomes. The high heterogeneity reflects the observed variability in phenotype. Because of underreporting, we observed reporting bias and a high risk of bias. We recommend standardizing study design by optimal time point and method chosen for readout measures to limit the variability. This contributes to improved reproducibility and thereby eventually improves the translational value of the RUPP model.

IL-33 Signaling Inhibition Leads to a Preeclampsia-Like Phenotype in Pregnant Rats

PROBLEM

Preeclampsia (PE) is a hypertensive pregnancy disorder that is a leading cause of maternal and fetal morbidity and mortality characterized by maternal vascular dysfunction, oxidative stress, chronic immune activation, and excessive inflammation. No cure exists beyond delivery of the fetal-placental unit and the mechanisms driving pathophysiology are not fully understood. However, aberrant immune responses have been extensively characterized in clinical studies and shown to mediate PE pathophysiology in animal studies. One pathway that may mediate aberrant immune responses in PE is deficiencies in the IL-33 signaling pathway. In this study, we aim to investigate the impact of IL-33 signaling inhibition on cNK, TH17, and TReg populations, vascular function, and maternal blood pressure during pregnancy.

METHOD OF STUDY

In this study, IL-33 signaling was inhibited using two different methods: intraperitoneal administration of recombinant ST2 (which acts as a decoy receptor for IL-33) and administration of a specific IL-33 neutralizing antibody. Maternal blood pressure, uterine artery resistance index, renal and placental oxidative stress, cNK, TH17, and TReg populations, various cytokines, and pre-proendothelin-1 levels were measured.

RESULTS

IL-33 signaling inhibition increased maternal blood pressure, uterine artery resistance, placental and renal oxidative stress. IL-33 signaling inhibition also increased placental cNK and TH17 and renal TH17 cells while decreasing placental TReg populations. IL-33 neutralization increased circulating cNK and TH17s and decreased circulating TRegs in addition to increasing pre-proendothelin-1 levels.

CONCLUSIONS

Data presented in this study demonstrate a role for IL-33 signaling in controlling vascular function and maternal blood pressure during pregnancy possibly by mediating innate and adaptive immune inflammatory responses, identifying the IL-33 signaling pathway as a potential therapeutic target for managing preeclampsia.

Bioinformatic Analysis Identifies Potential Extracellular Matrix Related Genes in the Pathogenesis of Early Onset Preeclampsia

Early-onset preeclampsia (EOPE) is a complex pregnancy complication that poses significant risks to the health of both mothers and fetuses, and research on its pathogenesis and pathophysiology remains insuffcient. This study aims to explore the role of candidate genes and their potential interaction mechanisms in EOPE through bioinformatics analysis techniques. Two gene expression datasets, GSE44711 and GSE74341, were obtained from the Gene Expression Omnibus (GEO) to identify differentially expressed genes (DEGs) between EOPE and gestational age-matched preterm control samples. Functional enrichment analysis was performed utilizing the kyoto encyclopedia of genes and genomes (KEGG), gene ontology (GO), and gene set enrichment analysis (GSEA). A protein-protein interaction (PPI) network was constructed using the STRING database, and hub DEGs were identified through Cytoscape software and comparative toxicogenomics database (CTD) analysis. Furthermore, a diagnostic logistic model was established using these hub genes, which were confirmed through reverse transcription polymerase chain reaction (RT-PCR). Finally, immune cell infiltration was analyzed using CIBERSORT. In total, 807 DEGs were identified in the GSE44711 dataset (451 upregulated genes and 356 downregulated genes), and 787 DEGs were identified in the GSE74341 dataset (446 upregulated genes and 341 downregulated genes). These DEGs were significantly enriched in various molecular functions such as extracellular matrix structural constituent, receptor-ligand activity binding, cytokine activity, and platelet-derived growth factor. KEGG and GSEA annotation revealed significant enrichment in pathways related to ECM-receptor interaction, PI3K-AKT signaling, and focal adhesion. Ten hub genes were identified through the CytoHubba plugin in Cytoscape. Among these hub genes, three key DEGs (COL1A1, SPP1, and THY1) were selected using CTD analysis and various topological methods in Cytoscape. The diagnostic logistic model based on these three genes exhibited high efficiency in predicting EOPE (AUC = 0.922). RT-PCR analysis confirmed the downregulation of these genes in EOPE, and immune cell infiltration analysis suggested the significant role of M1 and M2 macrophages in EOPE. In conclusion, this study highlights the association of three key genes (COL1A1, SPP1, and THY1) with EOPE and their contribution to high diagnostic efficiency in the logistic model. Additionally, it provides new insights for future research on EOPE and emphasizes the diagnostic value of these identified genes. More research is needed to explore their functional and diagnostic significance in EOPE.

Role of necroptosis and immune infiltration in preeclampsia: novel insights from bioinformatics analyses

BACKGROUND

Preeclampsia (PE) is a serious pregnancy complication that can adversely affect the mother and fetus. Necroptosis is a recently discovered new form of programmed cell death involved in the pathological process of various pregnancy complications. Our study aimed to identify the necroptosis-related differentially expressed genes (NRDEGs), create a diagnosis model and related disease subtypes model based on these genes, and further investigate their relationship with immune infiltration.

METHODS

In this study, we identified NRDEGs by analyzing data from various databases, including Molecular Signatures, GeneCards, and Gene Expression Omnibus (GEO). Using minor absolute shrinkage and selection operator (LASSO) and logistic Cox regression analysis, we developed a novel PE diagnosis model based on NRDEGs. Furthermore, we developed PE subtype models using consensus clustering analysis based on key gene modules screened out by weighted correlation network analysis (WGCNA). Finally, we identified the difference in immune infiltration between the PE and control groups as well as between both PE subtypes by analyzing the immune cell infiltration across combined datasets and PE datasets.

RESULTS

Our study discovered that the necroptosis pathway was significantly enriched and active in PE samples. We identified nine NRDEGs that involved in this pathway, including BRAF, PAWR, USP22, SYNCRIP, KRT86, MERTK, BAP1, CXCL5, and STK38. Additionally, we developed a diagnostic model based on a regression model including six NRDEGs and identified two PE subtypes: Cluster1 and Cluster2, based on key module genes. Furthermore, correlation analysis showed that the abundance of immune cell infiltration was related to necroptosis genes and PE disease subtypes.

CONCLUSION

According to the present study, necroptosis is a phenomenon that occurs in PE and is connected to immune cell infiltration. This result suggests that necroptosis and immune-related factors may be the underlying mechanisms of PE pathophysiology. This study opens new avenues for future research into PE's pathogenesis and treatment options.

Immune cell profiling of preeclamptic pregnant and postpartum women by single-cell RNA sequencing

Preeclampsia (PE), a leading cause of maternal and fetal morbidity and mortality, is closely related to the immune system alterations. However, little is known about the landscape and heterogeneity of maternal immune system at single-cell level among PE patients. In this study, peripheral blood mononuclear cells (PBMCs) were isolated from three early-onset preeclamptic pregnant women and two healthy control, respectively. Single-cell RNA sequencing was performed on 10× genomics platform and single-cell transcriptomes were obtained to characterize immune cell subgroups at the pregnant and postpartum stages. In total, 80,429 single-cell transcriptomes were obtained. 19 cellular compositions were identified, which were categorized into six cell types including T cells, natural killer (NK) cells, B cells, monocytes, plasmacytoid dendritic cells and conventional dendritic cells. There were excessive activation of B cells, monocytes and NK cells in PE patients at the pregnant stage based on comparative analysis. Lower immune response activation was noticed in CD4+ and CD8+ T cells in PE patients, especially the low-activation of memory T cells at the pregnant and postpartum stages. PE patients showed high activation of B cells in pregnancy persisted postpartum and lower activation of memory T cells, indicating their persistent effects on the pathogenesis and recurrence risk of PE. This study provide a broad characterization of the single-cell transcriptome of PBMCs in PE, which contributes to identification of immune imbalance for its monitoring and treatment.

Animal models of preeclampsia: investigating pathophysiology and therapeutic targets

Animal models have been critical in investigating the pathogenesis, mediators, and even therapeutic options for a number of diseases, including preeclampsia. Preeclampsia is the leading cause of maternal and fetal morbidity and mortality worldwide. The placenta is thought to play a central role in the pathogenesis of this disease because it releases antiangiogenic and proinflammatory factors into the maternal circulation, resulting in the maternal syndrome. Despite the deleterious effects preeclampsia has been shown to have on the mother and baby during pregnancy and postpartum, there is still no effective treatment for this disease. Although clinical studies in patients are crucial to identify the involvement of pathogenic factors in preeclampsia, there are obvious limitations that prevent detailed investigation of the quantitative importance of time-dependent mechanisms involved in this syndrome. Animal models allow investigators to perform proof-of-concept studies and examine whether certain factors found in women with preeclampsia mediate hypertension and other manifestations of this disease. In this brief review, we summarize some of the more widely studied models used to investigate pathophysiological mechanisms that are thought to be involved in preeclampsia. These include models of placental ischemia, angiogenic imbalance, and maternal immune activation. Infusion of preeclampsia-related factors into animals has been widely studied to understand the specific mediators of this disease. These models have been included, in addition to a number of genetic models involved in overexpression of the renin-angiotensin system, complement activation, and trophoblast differentiation. Together, these models cover multiple mechanisms of preeclampsia from trophoblast dysfunction and impaired placental vascularization to the excess circulating placental factors and clinical manifestation of this disease. Most animal studies have been performed in rats and mice; however, we have also incorporated nonhuman primate models in this review. Preclinical animal models not only have been instrumental in understanding the pathophysiology of preeclampsia but also continue to be important tools in the search for novel therapeutic options for the treatment of this disease.

Manipulating CD4+ T Cell Pathways to Prevent Preeclampsia

Preeclampsia (PreE) is a placental disorder characterized by hypertension (HTN), proteinuria, and oxidative stress. Individuals with PreE and their children are at an increased risk of serious short- and long-term complications, such as cardiovascular disease, end-organ failure, HTN, neurodevelopmental disorders, and more. Currently, delivery is the only cure for PreE, which remains a leading cause of morbidity and mortality among pregnant individuals and neonates. There is evidence that an imbalance favoring a pro-inflammatory CD4+ T cell milieu is associated with the inadequate spiral artery remodeling and subsequent oxidative stress that prime PreE’s clinical symptoms. Immunomodulatory therapies targeting CD4+ T cell mechanisms have been investigated for other immune-mediated inflammatory diseases, and the application of these prevention tactics to PreE is promising, as we review here. These immunomodulatory therapies may, among other things, decrease tumor necrosis factor alpha (TNF-α), cytolytic natural killer cells, reduce pro-inflammatory cytokine production [e.g. interleukin (IL)-17 and IL-6], stimulate regulatory T cells (Tregs), inhibit type 1 and 17 T helper cells, prevent inappropriate dendritic cell maturation, and induce anti-inflammatory cytokine action [e.g. IL-10, Interferon gamma (IFN-γ)]. We review therapies including neutralizing monoclonal antibodies against TNF-α, IL-17, IL-6, and CD28; statins; 17-hydroxyprogesterone caproate, a synthetic hormone; adoptive exogenous Treg therapy; and endothelin-1 pathway inhibitors. Rebalancing the maternal inflammatory milieu may allow for proper spiral artery invasion, placentation, and maternal tolerance of foreign fetal/paternal antigens, thereby combatting early PreE pathogenesis.

Cellular immune responses in the pathophysiology of preeclampsia

Preeclampsia, defined as new-onset hypertension accompanied by proteinuria occurring at 20 weeks of gestation or later, is a leading cause of perinatal morbidity and mortality worldwide. The pathophysiology of this major multi-systemic syndrome includes defective deep placentation, oxidative stress, endothelial dysfunction, the presence of an anti-angiogenic state, and intravascular inflammation, among others. In this review, we provide a comprehensive overview of the cellular immune responses involved in the pathogenesis of preeclampsia. Specifically, we summarize the role of innate and adaptive immune cells in the maternal circulation, reproductive tissues, and at the maternal-fetal interface of women affected by this pregnancy complication. The major cellular subsets involved in the pathogenesis of preeclampsia are regulatory T cells, effector T cells, NK cells, monocytes, macrophages, and neutrophils. We also summarize the literature on those immune cells that have been less characterized in this clinical condition, such as γδ T cells, invariant natural killer T cells, dendritic cells, mast cells, and B cells. Moreover, we discuss in vivo studies utilizing a variety of animal models of preeclampsia to further support the role of immune cells in this disease. Finally, we highlight the existing gaps in knowledge of the immunobiology of preeclampsia that require further investigation. The goal of this review is to promote translational research leading to clinically relevant strategies that can improve adverse perinatal outcomes resulting from the obstetrical syndrome of preeclampsia.

Placental hypoxia: What have we learnt from small animal models?

Intrauterine hypoxia is a feature of pregnancy complications, both at high altitude and sea level. To understand the placental response to reduced oxygen availability, small animal models of maternal inhalation hypoxia (MIH) or reduced uterine perfusion pressure (RUPP) may be utilised. The aim of this review was to compare the findings of those studies to identify the role of oxygen availability in adapting placental structural and functional phenotypes in relation to fetal outcome. It also sought to explore the evidence for the involvement of particular genes and protein signalling pathways in the placenta in mediating hypoxia driven alterations. The data available demonstrate that both MIH and RUPP can induce placental hypoxia, which affects placental structure and vascularity, as well as glucose, amino acid, calcium and possibly lipid transport capacity. In addition, changes have been observed in HIF, VEGF, insulin/IGF2, AMPK, mTOR, PI3K and PPARγ signalling, which may be key in linking together observed phenotypes under conditions of placental hypoxia. Many different manipulations have been examined, with varied outcomes depending on the intensity, timing and duration of the insult. Some manipulations have detrimental effects on placental phenotype, viability and fetal growth, whereas in others, the placenta appears to adapt to uphold fetal growth despite the challenge of low oxygen. Together these data suggest a complex response of the placenta to reduced oxygen availability, which links to changes in fetal outcomes. However, further work is required to explore the role of fetal sex, altered maternal physiology and placental molecular mechanisms to fully understand placental responses to hypoxia and their relevance for pregnancy outcome.

Preeclampsia and Neurodevelopmental Outcomes: Potential Pathogenic Roles for Inflammation and Oxidative Stress?

Preeclampsia (PE) is a common and serious hypertensive disorder of pregnancy that occurs in approximately 3-5% of first-time pregnancies and is a well-known leading cause of maternal and neonatal mortality and morbidity. In recent years, there has been accumulating evidence that in utero exposure to PE acts as an environmental risk factor for various neurodevelopmental disorders, particularly autism spectrum disorder and ADHD. At present, the mechanism(s) mediating this relationship are uncertain. In this review, we outline the most recent evidence implicating a causal role for PE exposure in the aetiology of various neurodevelopmental disorders and provide a novel interpretation of neuroanatomical alterations in PE-exposed offspring and how these relate to their sub-optimal neurodevelopmental trajectory. We then postulate that inflammation and oxidative stress, two prominent features of the pathophysiology of PE, are likely to play a major role in mediating this association. The increased inflammation in the maternal circulation, placenta and fetal circulation in PE expose the offspring to both prenatal maternal immune activation-a risk factor for neurodevelopmental disorders, which has been well-characterised in animal models-and directly higher concentrations of pro-inflammatory cytokines, which adversely affect neuronal development. Similarly, the exaggerated oxidative stress in the mother, placenta and foetus induces the placenta to secrete factors deleterious to neurons, and exposes the fetal brain to directly elevated oxidative stress and thus adversely affects neurodevelopmental processes. Finally, we describe the interplay between inflammation and oxidative stress in PE, and how both systems interact to potentially alter neurodevelopmental trajectory in exposed offspring.

Investigation of interleukin-2-mediated changes in blood pressure, fetal growth restriction, and innate immune activation in normal pregnant rats and in a preclinical rat model of preeclampsia

Two important clinical features of preeclampsia (PE) are hypertension and fetal growth restriction. The reduced uterine perfusion pressure (RUPP) preclinical rat model of PE exhibits both of these features. Moreover, RUPP and PE women have elevated vasoconstrictor peptide endothelin-1 (ET-1) and inflammation. Interleukin-2 (IL-2) is a cytokine that regulates NK cell activity and is elevated in miscarriage, PE, and RUPP rats. The objective of this study was to examine a role for IL-2 in NK cell activation, fetal growth restriction, and hypertension during pregnancy by either infusion of IL-2 or blockade of IL-2 (basiliximab) in normal pregnant (NP) and RUPP rats. On gestational day 14, NP and RUPP rats received low (LD), middle (MD), or high dose (HD) IL-2 (0.05, 0.10, or 0.20 ng/ml) IP or basiliximab (0.07 mg per rat) by IV infusion. On day 19, blood pressure (MAP), pup weights, and blood were collected. Basiliximab had no effect on blood pressure, however, significantly lowered NK cells and may have worsened overall fetal survival in RUPP rats. However, IL-2 LD (102 ± 4 mmHg) and IL-2 HD (105 ± 6 mmHg) significantly lowered blood pressure, ET-1, and activated NK cells compared to control RUPPs (124 ± 3 mmHg, p < 0.05). Importantly, IL-2 in RUPP rats significantly reduced fetal weight and survival. These data indicate that although maternal benefits may have occurred with low dose IL-2 infusion, negative effects were seen in the fetus. Moreover, inhibition of IL-2 signaling did not have favorable outcome for the mother or fetus.

Preeclampsia: Linking Placental Ischemia with Maternal Endothelial and Vascular Dysfunction

Preeclampsia (PE), a hypertensive disorder, occurs in 3% to 8% of pregnancies in the United States and affects over 200,000 women and newborns per year. The United States has seen a 25% increase in the incidence of PE, largely owing to increases in risk factors, including obesity and cardiovascular disease. Although the etiology of PE is not clear, it is believed that impaired spiral artery remodeling of the placenta reduces perfusion, leading to placental ischemia. Subsequently, the ischemic placenta releases antiangiogenic and pro-inflammatory factors, such as cytokines, reactive oxygen species, and the angiotensin II type 1 receptor autoantibody (AT1-AA), among others, into the maternal circulation. These factors cause widespread endothelial activation, upregulation of the endothelin system, and vasoconstriction. In turn, these changes affect the function of multiple organ systems including the kidneys, brain, liver, and heart. Despite extensive research into the pathophysiology of PE, the only treatment option remains early delivery of the baby and importantly, the placenta. While premature delivery is effective in ameliorating immediate risk to the mother, mounting evidence suggests that PE increases risk of cardiovascular disease later in life for both mother and baby. Notably, these women are at increased risk of hypertension, heart disease, and stroke, while offspring are at risk of obesity, hypertension, and neurological disease, among other complications, later in life. This article aims to discuss the current understanding of the diagnosis and pathophysiology of PE, as well as associated organ damage, maternal and fetal outcomes, and potential therapeutic avenues. © 2021 American Physiological Society. Compr Physiol 11:1315-1349, 2021.

Preeclamptic Women Have Decreased Circulating IL-10 (Interleukin-10) Values at the Time of Preeclampsia Diagnosis: Systematic Review and Meta-Analysis

A key immunomodulatory cytokine, IL-10 (interleukin-10), has been shown to be dysregulated in preeclampsia, a pregnancy-specific hypertensive disorder, further characterized by multi-system involvement. However, studies have reported inconsistent findings about circulating IL-10 levels in preeclamptic versus normotensive pregnancies. The aim of the present systematic review and meta-analysis was to assess circulating IL-10 levels in preeclamptic and normotensive pregnancies at 2 time points: before, and at the time of preeclampsia diagnosis. PubMED, EMBASE, and Web of Science databases were searched to include all published studies examining circulating IL-10 levels in preeclamptic and normotensive pregnancies. Differences in IL-10 levels were evaluated by standardized mean differences. Of 876 abstracts screened, 56 studies were included in the meta-analysis. Circulating IL-10 levels were not different before the time of active disease (standardized mean differences, -0.01 [95% CI, -0.11 to 0.08]; P=0.76). At the time of active disease, women with preeclampsia (n=1599) had significantly lower IL-10 levels compared with normotensive controls (n=1998; standardized mean differences, -0.79 [95% CI, -1.22 to -0.35]; P=0.0004). IL-10 levels were lower in both early/severe and late/mild forms of preeclampsia. Subgroup analysis revealed that IL-10 measurement methodology (ELISA or multiplex bead array) and the sample type (plasma or serum) significantly influenced the observed differences, with the use of sera paired with ELISA technology providing the best distinction in IL-10 levels between preeclamptic and normotensive pregnancies. These findings support the role of decreased IL-10 levels in the pathophysiology of preeclampsia. Future studies should address the therapeutic potential of IL-10 in preeclampsia.

Nicotinamide and Demographic and Disease transitions: Moderation is Best

Good health and rapid progress depend on an optimal dose of nicotinamide. Too little meat triggers the neurodegenerative condition pellagra and tolerance of symbionts such as tuberculosis (TB), risking dysbioses and impaired resistance to acute infections. Nicotinamide deficiency is an overlooked diagnosis in poor cereal-dependant economies masquerading as 'environmental enteropathy' or physical and cognitive stunting. Too much meat (and supplements) may precipitate immune intolerance and autoimmune and allergic disease, with relative infertility and longevity, via the tryptophan-nicotinamide pathway. This switch favours a dearth of regulatory T (Treg) and an excess of T helper cells. High nicotinamide intake is implicated in cancer and Parkinson's disease. Pro-fertility genes, evolved to counteract high-nicotinamide-induced infertility, may now be risk factors for degenerative disease. Moderation of the dose of nicotinamide could prevent some common diseases and personalised doses at times of stress or, depending on genetic background or age, may treat some other conditions.

Inflammatory mediators: a causal link to hypertension during preeclampsia

Preeclampsia (PE) is a hypertensive disorder that occurs after 20 weeks of gestation, implicating the placenta as a key offender. PE is associated with an imbalance among B lymphocytes, CD4+ T lymphocytes, NK cells and increased inflammatory cytokines. During early onset PE, trophoblast invasion and placentation are impaired, leading to reduced blood flow to the fetus. In all spectrums of this disorder, a shift towards a pro-inflammatory state where regulatory cells and cytokines are decreased occurs. Specifically, inflammatory CD4+ T-cells and inflammatory cytokines are increased while CD4+ T regulatory cells (Tregs) and immunosuppressive cytokines such as IL-4 and IL-10 are decreased resulting in B cell activation, production of autoantibodies, endothelial dysfunction and hypertension associated with PE. However, the stimulus for these imbalances is unknown and need to be fully understood so that effective treatments that target the pathogenesis of the disease can be designed. Therefore, this review will focus on the pathways involving CD4+ , TH1, TH2, Tregs, TH17s, B cells, and NK cells in the pathophysiology of PE. LINKED ARTICLES: This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc.

Developmental origins of nonalcoholic fatty liver disease as a risk factor for exaggerated metabolic and cardiovascular-renal disease

Intrauterine growth restriction (IUGR) is linked to increased risk for chronic disease. Placental ischemia and insufficiency in the mother are implicated in predisposing IUGR offspring to metabolic dysfunction, including hypertension, insulin resistance, abnormalities in glucose homeostasis, and nonalcoholic fatty liver disease (NAFLD). It is unclear whether these metabolic disturbances contribute to the developmental origins of exaggerated cardiovascular-renal disease (CVRD) risk accompanying IUGR. IUGR impacts the pancreas, adipose tissue, and liver, which are hypothesized to program for hepatic insulin resistance and subsequent NAFLD. NAFLD is projected to become the major cause of chronic liver disease and contributor to uncontrolled type 2 diabetes mellitus, which is a leading cause of chronic kidney disease. While NAFLD is increased in experimental models of IUGR, lacking is a full comprehension of the mechanisms responsible for programming of NAFLD and whether this potentiates susceptibility to liver injury. The use of well-established and clinically relevant rodent models, which mimic the clinical characteristics of IUGR, metabolic disturbances, and increased blood pressure in the offspring, will permit investigation into mechanisms linking adverse influences during early life and later chronic health. The purpose of this review is to propose mechanisms, including those proinflammatory in nature, whereby IUGR exacerbates the pathogenesis of NAFLD and how these adverse programmed outcomes contribute to exaggerated CVRD risk. Understanding the etiology of the developmental origins of chronic disease will allow investigators to uncover treatment strategies to intervene in the mother and her offspring to halt the increasing prevalence of metabolic dysfunction and CVRD.

Development of a core outcome set for immunomodulation in pregnancy (COSIMPREG): a protocol for a systematic review and Delphi study

INTRODUCTION

To establish pregnancy, the maternal immune system must adapt to tolerate the semiallogenic fetus. Less than optimal adaptation of the maternal immune system during (early) pregnancy is implicated in several complications of pregnancy. The development of effective immune modulation interventions as preventive or therapeutic strategies for pregnancy complications holds promise. Several studies sought to evaluate the safety and effectiveness of various approaches. However, a limitation is the high variability in clinical and immune outcomes that are reported. We, therefore, aim to develop a core outcome set for application to studies of immune modulation in pregnancy (COSIMPREG).

METHODS AND ANALYSIS

We will use a stepwise approach to develop a COSIMPREG. First, we will perform a systematic review to identify reported outcomes. For this review, Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines will be followed. Second, we will use the Delphi method to develop a preliminary COSIMPREG. In three rounds, the outcomes of the systematic review will be scored. A panel comprising experts from relevant disciplines and diverse geographical locations will be assembled until a sufficient quality of the panel is reached. We will use predefined decision rules for outcomes. After each round outcomes, including scores, will be returned to the panel for further refinement. The outcomes not excluded after the third round will be taken to a consensus meeting. In this meeting, experts from all relevant disciplines will discuss and finalise the COSIMPREG.

ETHICS AND DISSEMINATION

For this study ethical approval is not required. The systematic review will be published in an appropriate open access reproductive immunology journal. Once the COSIMPREG is finalised, it will be published in an open access reproductive immunology journal, and disseminated at appropriate international meetings, as well as through relevant research and scientific societies. Experts involved in the Delphi study will be asked to give informed consent.

Reduction in Regulatory T Cells in Early Pregnancy Causes Uterine Artery Dysfunction in Mice

Preeclampsia, fetal growth restriction, and miscarriage remain important causes of maternal and perinatal morbidity and mortality. These complications are associated with reduced numbers of a specialized T lymphocyte subset called regulatory T cells (Treg cells) in the maternal circulation, decidua, and placenta. Treg cells suppress inflammation and prevent maternal immunity toward the fetus, which expresses foreign paternal alloantigens. Treg cells are demonstrated to contribute to vascular homeostasis, but whether Treg cells influence the vascular adaptations essential for a healthy pregnancy is unknown. Thus, using a mouse model of Treg-cell depletion, we investigated the hypothesis that depletion of Treg cells would cause increased inflammation and aberrant uterine artery function. Here, we show that Treg-cell depletion resulted in increased embryo resorption and increased production of proinflammatory cytokines. Mean arterial pressure exhibited greater modulation by NO in Treg cell-deficient mice because the L-N^G-nitroarginine methyl ester-induced increase in mean arterial pressure was 46% greater compared with Treg cell-replete mice. Uterine artery function, which is essential for the supply of nutrients to the placenta and fetus, demonstrated dysregulated hemodynamics after Treg-cell depletion. This was evidenced by increased uterine artery resistance and pulsatility indices and enhanced conversion of bET-1 (big endothelin-1) to the active and potent vasoconstrictor, ET-1 (endothelin-1). These data demonstrate an essential role for Treg cells in modulating uterine artery function during pregnancy and implicate Treg-cell control of maternal vascular function as a key mechanism underlying normal fetal and placental development.

The Role of Interleukin-10 in the Pathophysiology of Preeclampsia

PURPOSE OF REVIEW

The pathophysiology of preeclampsia is complex and not entirely understood. A key feature in preeclampsia development is an immunological imbalance that shifts the maternal immune response from one of tolerance towards one promoting chronic inflammation and endothelial dysfunction. As a key regulator of immunity, IL-10 not only has immunomodulatory activity, but also directly benefits vasculature and promotes successful cellular interactions at the maternal-fetal interface. Here we focus on the mechanisms by which the dysregulation of IL-10 may contribute to the pathophysiology of preeclampsia.

RECENT FINDINGS

Dysregulation of IL-10 has been demonstrated in various animal models of preeclampsia. Decreased IL-10 production in both placenta and peripheral blood mononuclear cells has been reported in human studies, but with inconsistent results. The significance of IL-10 in preeclampsia has shifted from a key biomarker to one with therapeutic potential. As such, a better understanding of the role of this cytokine in the pathophysiology of preeclampsia is of paramount importance.

Preeclampsia: From Inflammation to Immunoregulation

Preeclampsia (PE) affects 5% to 7% of pregnant women each year worldwide, accounts for up to 18% of maternal deaths in the United States each year, and is the number 1 cause of premature births. Preeclampsia is associated with hypertension after the 20th week of gestation with or without proteinuria, in conjunction with fetal growth restriction, maternal endothelial dysfunction, and chronic immune activation. The mechanisms leading to the development of PE are unclear. However, it is thought that shallow trophoblast invasion and insufficient remodeling of uterine spiral arteries result in placental ischemia. Consequently, an immune imbalance characterized by increases in proinflammatory CD4⁺ T cells and cytokines along with decreases in regulatory T cells and anti-inflammatory cytokines occurs. This imbalance leads to chronic inflammation and ensuing oxidative stress, proinflammatory cytokines, and autoantibodies. Studies performed in our laboratories, using the Reduced Uterine Perfusion Pressure (RUPP) rat model of placental ischemia, have demonstrated a role for this immune imbalance to mediate PE pathophysiology and identified potential mechanisms of immunoregulation that may be of benefit in the treatment of PE. Therefore, the purpose of this commentary is to review studies demonstrating the positive effects of immunoregulatory factors in the RUPP rat model of PE. Restoration of the immune balance in PE may be a potential strategy for the development of therapeutic interventions that could improve maternal and fetal outcomes associated with this maternal syndrome.