Analysis of plasma elastase levels in early and late onset preeclampsia

Targeting Neutrophil Extracellular Trap Formation: Exploring Promising Pharmacological Strategies for the Treatment of Preeclampsia

Neutrophils, which constitute the most abundant leukocytes in human blood, emerge as crucial players in the induction of endothelial cell death and the modulation of endothelial cell responses under both physiological and pathological conditions. The hallmark of preeclampsia is endothelial dysfunction induced by systemic inflammation, in which neutrophils, particularly through the formation of neutrophil extracellular traps (NETs), play a pivotal role in the development and perpetuation of endothelial dysfunction and the hypertensive state. Considering the potential of numerous pharmaceutical agents to attenuate NET formation (NETosis) in preeclampsia, a comprehensive assessment of the extensively studied candidates becomes imperative. This review aims to identify mechanisms associated with the induction and negative regulation of NETs in the context of preeclampsia. We discuss potential drugs to modulate NETosis, such as NF-κβ inhibitors, vitamin D, and aspirin, and their association with mutagenicity and genotoxicity. Strong evidence supports the notion that molecules involved in the activation of NETs could serve as promising targets for the treatment of preeclampsia.

Identification of the role of DAB2 and CXCL8 in uterine spiral artery remodeling in early-onset preeclampsia

Aberrant remodeling of uterine spiral arteries (SPA) is strongly associated with the pathogenesis of early-onset preeclampsia (EOPE). However, the complexities of SPA transformation remain inadequately understood. We conducted a single-cell RNA sequencing analysis of whole placental tissues derived from patients with EOPE and their corresponding controls, identified DAB2 as a key gene of interest and explored the mechanism underlying the communication between Extravillous trophoblast cells (EVTs) and decidual vascular smooth muscle cells (dVSMC) through cell models and a placenta-decidua coculture (PDC) model in vitro. DAB2 enhanced the motility and viability of HTR-8/SVneo cells. After exposure to conditioned medium (CM) from HTR-8/SVneoshNC cells, hVSMCs exhibited a rounded morphology, indicative of dedifferentiation, while CM-HTR-8/SVneoshDAB2 cells displayed a spindle-like morphology. Furthermore, the PDC model demonstrated that CM-HTR-8/SVneoshDAB2 was less conducive to vascular remodeling. Further in-depth mechanistic investigations revealed that C-X-C motif chemokine ligand 8 (CXCL8, also known as IL8) is a pivotal regulator governing the dedifferentiation of dVSMC. DAB2 expression in EVTs is critical for orchestrating the phenotypic transition and motility of dVSMC. These processes may be intricately linked to the CXCL8/PI3K/AKT pathway, underscoring its central role in intricate SPA remodeling.

The novel role of activating receptor KIR2DS5 in preeclampsia

Preeclampsia (PE) is a serious complication of pregnancy. Decidual natural killer (dNK) cells were reported to participate in the remodeling of spiral arteries through producing a group of cytokines, including granulocyte-macrophage colony stimulating factor (GM-CSF). KIR2DS5 is an activating receptor of NK cells that specifically recognizes HLA-C2 on trophoblasts. Currently, there are no reports regarding the precise mechanism of KIR2DS5 in PE. This study included 30 PE patients and 30 healthy pregnant women. We found that the expressions of KIR2DS5 were significantly lower in PE deciduae compared to those of healthy pregnancies. By transfecting knockdown and overexpression lentivirus vectors of KIR2DS5 into dNK cells isolated from deciduae of early pregnancy, we altered the KIR2DS5 expression level in dNK cells. Then, these dNK cells and trophoblast cell lines were co-cultured as trophoblast-dNK cells. In the trophoblast-dNK cells, we examined the influence of KIR2DS5 on the biological manifestations of trophoblasts. As anticipated, overexpression of KIR2DS5 could facilitate cell proliferation, migration, and invasion. Furthermore, increased expression of KIR2DS5 inhibited cell apoptosis and enhanced the progression of cells from theG1 to theS stage. Further mechanistic study demonstrated a positive relationship between KIR2DS5 and GM-CSF in trophoblast-dNK cells. Accordingly, our observations indicated that a decrease in KIR2DS5 could reduce the expression of GM-CSF via the JAK2/STAT5 pathway, resulting in the failure of the activated signal to be transmitted to dNK cells and ultimately leading to the occurrence of PE. KIR2DS5 may be a new contributor for the prediction and diagnosis of PE.

The role of immune cells and mediators in preeclampsia

Preeclampsia is a hypertensive disorder of major concern in pregnancy than can lead to intrauterine growth restriction, placental abruption and stillbirth. The pathophysiology of preeclampsia is multifactorial, including not only kidney dysfunction but also endothelial dysfunction, as the maternal endothelium becomes exposed to placental factors that are released into the circulation and increase systemic levels of vasoconstrictors, oxidative stress, anti-angiogenic factors and inflammatory mediators. Importantly, inflammation can lead to insufficient placental perfusion and low birthweight in offspring. Various innate and adaptive immune cells and mediators have been implicated in the development of preeclampsia, in which oxidative stress is associated with activation of the maternal inflammatory response. Immune cells such as regulatory T cells, macrophages, natural killer cells, and neutrophils are known to have major causative roles in the pathology of preeclampsia, but the contributions of additional immune cells such as B cells, inflammatory cytokines and anti-angiotensin II type 1 receptor autoantibodies are also now recognized. Immunological interventions, therefore, have therapeutic potential in this disease. Here, we provide an overview of the immune responses that are involved in the pathogenesis of preeclampsia, including the role of innate and adaptive immune cells and mediators.

New immune horizons in therapeutics and diagnostic approaches to Preeclampsia

Hypertensive disorders of pregnancy (HDP) are one of the commonest maladies, affecting 5%-10% of pregnancies worldwide. The American College of Obstetricians and Gynecologists (ACOG) identifies four categories of HDP, namely gestational hypertension (GH), Preeclampsia (PE), chronic hypertension (CH), and CH with superimposed PE. PE is a multisystem, heterogeneous disorder that encompasses 2%-8% of all pregnancy-related complications, contributing to about 9% to 26% of maternal deaths in low-income countries and 16% in high-income countries. These translate to 50 000 maternal deaths and over 500 000 fetal deaths worldwide, therefore demanding high priority in understanding clinical presentation, screening, diagnostic criteria, and effective management. PE is accompanied by uteroplacental insufficiency leading to vascular and metabolic changes, vasoconstriction, and end-organ ischemia. PE is diagnosed after 20 weeks of pregnancy in women who were previously normotensive or hypertensive. Besides shallow trophoblast invasion and inadequate remodeling of uterine arteries, dysregulation of the nonimmune system has been the focal point in PE. This results from aberrant immune system activation and imbalanced differentiation of T cells. Further, a failure of tolerance toward the semi-allogenic fetus results due to altered distribution of Tregs such as CD4+FoxP3+ or CD4+CD25+CD127(low) FoxP3+ cells, thereby creating a cytotoxic environment by suboptimal production of immunosuppressive cytokines like IL-10, IL-4, and IL-13. Also, intracellular production of complement protein C5a may result in decreased FoxP3+ regulatory T cells. With immune system dysfunction as a major driver in PE pathogenesis, it is logical that therapeutic targeting of components of the immune system with pharmacologic agents like anti-inflammatory and immune-modulating molecules are either being used or under clinical trial. Cholesterol synthesis inhibitors like Pravastatin may improve placental perfusion in PE, while Eculizumab (monoclonal antibody inhibiting C5) and small molecular inhibitor of C5a, Zilucoplan are under investigation. Monoclonal antibody against IL-17(Secukinumab) has been proposed to alter the Th imbalance in PE. Autologous Treg therapy and immune checkpoint inhibitors like anti-CTLA-4 are emerging as new candidates in immune horizons for PE management in the future.

Aspirin Inhibits the Inflammatory Response of Protease-Activated Receptor 1 in Pregnancy Neutrophils: Implications for Treating Women with Preeclampsia

Neutrophils expressing cyclooxygenase-2 (COX-2) extensively infiltrate maternal blood vessels in preeclampsia, associated with vascular inflammation. Because pregnancy neutrophils also express protease-activated receptor 1 (PAR-1, F2R thrombin receptor), which they do not in non-pregnant subjects, they can be activated by proteases. We tested the hypothesis that aspirin at a dose sufficient to inhibit COX-2 would reduce inflammatory responses in preeclampsia neutrophils. Neutrophils were isolated from normal pregnant and preeclamptic women at approximately 30 weeks' gestation. Normal pregnancy neutrophils were treated with elastase, a protease elevated in preeclampsia, or elastase plus aspirin to inhibit COX-2, or elastase plus pinane thromboxane, a biologically active structural analog of thromboxane and a thromboxane synthase inhibitor. Preeclamptic pregnancy neutrophils were treated with the same doses of aspirin or pinane thromboxane. Confocal microscopy with immunofluorescence staining was used to determine the cellular localization of the p65 subunit of nuclear factor-kappa B (NF-κB) and media concentrations of thromboxane were measured to evaluate the inflammatory response. In untreated neutrophils of normal pregnant women, p65 was localized to the cytosol. Upon stimulation with elastase, p65 translocated from the cytosol to the nucleus coincident with increased thromboxane production. When neutrophils were co-treated with aspirin or pinane thromboxane, elastase was not able to cause nuclear translocation of p65 or increase thromboxane. In untreated neutrophils of preeclamptic women, the p65 subunit was present in the nucleus and thromboxane production was elevated, but when preeclamptic neutrophils were treated with aspirin or pinane thromboxane, p65 was cleared from the nucleus and returned to the cytosol along with decreased thromboxane production. These findings suggest that COX-2 is a downstream mediator of PAR-1 and demonstrate that PAR-1- mediated inflammation can be inhibited by aspirin. Given the extensive and ubiquitous expression of PAR-1 and COX-2 in preeclamptic women, consideration should be given to treating women with preeclampsia using a dose of aspirin sufficient to inhibit COX-2.

The Pregnancy Zone Protein (PZP) is significantly downregulated in the placenta of preeclampsia and HELLP syndrome patients

Preeclampsia is characterized by maternal hypertension and multi-organ injury. Elongation factor Tu GTP binding domain containing 2 (EFTUD 2) and the Pregnancy Zone Protein (PZP) seem to be important immunomodulatory factors in early gestation. Little is known about the role of EFTUD2 and PZP in disorders of late pregnancy like preeclampsia, HELLP syndrome and intrauterine growth restriction (IUGR). PZP, EFTUD2 and hCG expression was investigated by immunohistochemistry in the placenta of healthy pregnancies (n = 13), preeclampsia (n = 11), HELLP syndrome (n = 12) and IUGR (n = 8). Correlation analysis of protein expression was performed via Spearman correlation coefficient. The characterization of EFTUD2 and PZP expressing cells was evaluated by double-immunofluorescence. After cultivation of the chorion carcinoma cell line BeWo with hCG the expression of PZP and EFTUD2 was investigated by immunocytochemistry. PZP expression was significantly downregulated in the syncytiotrophoblast (ST) and extravillous trophoblast (EVT) of preeclampsia (ST: p 0.001, EVT:p = 0.019) and HELLP syndrome (ST: p = 0.004, EVT: p = 0.035). The expression of EFTUD2 was significantly lower in preeclampsia (ST: p = 0.003, EVT: p 0.001), HELLP syndrome (ST: p = 0.021, EVT: = 0.001, EVT: p = 0.001). EVTs were identified as EFTUD2 and PZP expressing cells by double-immunofluorescence. Stimulation of BeWo chorion carcinoma cells with hCG 1000 IU/mL for 48 h resulted in a significant upregulation of PZP expression (p = 0.027). Our results indicate that PZP and EFTUD2 might be involved in the development of placental dysfunction in preeclampsia and HELLP syndrome.

Gene Expression of Pregnancy Neutrophils Differs for Protease versus Lipopolysaccharide Stimulation

Neutrophils, which extensively infiltrate maternal systemic blood vessels in preeclampsia, express protease-activated receptor 1 (PAR-1) but only during pregnancy. Neutrophils are generally considered to be non-specific in their response, but the pregnancy-specific expression of PAR-1 could result in a gene expression profile unique to pregnancy, which could help explain why the maternal inflammatory response in preeclampsia is systemic rather than localized. We sought to determine if gene expression of pregnancy neutrophils would differ if stimulated by a protease versus bacterial lipopolysaccharide (LPS). We isolated neutrophils from normal pregnant women at 30 weeks’ gestation and cultured them with elastase or LPS. We used elastase because it is a protease elevated in women with preeclampsia, and it activates pregnancy neutrophils via PAR-1. RNA was isolated from the neutrophils for sequencing of the transcriptomes. We discovered many differences in the gene expression profiles. For example, exposure to elastase resulted in three times more uniquely expressed genes than LPS, and the number of significantly differentially upregulated and downregulated genes was greater for elastase. Analysis of canonical pathways revealed similarities for innate immunity but also differences. LPS treatment enriched more pathways, but elastase activated more genes in each pathway. Elastase treatment enriched the MAPK signaling pathway, whereas LPS did not. This is significant because MAPK is a key mediator of transcriptional responses. These findings indicate that protease stimulation of pregnancy neutrophils results in a different profile than stimulation with LPS, which may help explain why the sterile inflammatory response of preeclampsia is systemic and unique to pregnancy.

Bovine sperm samples induce different NET phenotypes in a NADPH oxidase-, PAD4-, and Ca++-dependent process†

Deposition of sperm during artificial insemination in the bovine female reproductive tract results in early host innate immune reactions of polymorphonuclear neutrophils (PMNs). Furthermore, sperm-mediated neutrophil extracellular trap (NET) formation (NETosis) was recently reported to occur in different mammalian species, including humans. We, here, investigated the interactions of bovine PMN with different semen-derived samples and analyzed in more depth molecular aspects of this effector mechanism. Overall, confrontation of PMN with sperm/cell preparation (SCP) resulted in a rapid and dose-dependent NET formation leading to effective spermatozoa entrapment. Thereby, spermatozoa induced different phenotypes of NETs. Immunostaining analyses revealed the presence of histones (H3), neutrophil elastase (NE), and pentraxin (PTX) in sperm-triggered NET structures. Fresh SCP strongly induced NETosis than frozen-thawed ones. The level of NETosis was not related to spermatozoa viability. SCP as well as purified sperm cells (SCs) and supernatant (SN) induce NETosis, although the reaction in SC was lower. Enhanced levels of oxygen consumption and proton leak in PMN revealed sperm SNs but not purified SCs as PMN activators. Functional inhibition experiments revealed sperm-triggered NETosis as an NADPH oxidase- and peptidylarginine deiminase 4-dependent process and proved to be dependent on intra- and extracellular Ca++ influxes while myeloperoxidase activity and as ERK1/2- and PI3K-related signaling pathways did not seem to play a pivotal role in this effector mechanism. From these findings, we speculate that sperm-derived NETosis might also occur in vivo during artificial insemination and might therefore play a role related to reduced fertility.

Mechanisms of Key Innate Immune Cells in Early- and Late-Onset Preeclampsia

Preeclampsia is a complex cardiovascular disorder of pregnancy with underlying multifactorial pathogeneses; however, its etiology is not fully understood. It is characterized by the new onset of maternal hypertension after 20 weeks of gestation, accompanied by proteinuria, maternal organ damage, and/or uteroplacental dysfunction. Preeclampsia can be subdivided into early- and late-onset phenotypes (EOPE and LOPE), diagnosed before 34 weeks or from 34 weeks of gestation, respectively. Impaired placental development in early pregnancy and subsequent growth restriction is often associated with EOPE, while LOPE is associated with maternal endothelial dysfunction. The innate immune system plays an essential role in normal progression of physiological pregnancy and fetal development. However, inappropriate or excessive activation of this system can lead to placental dysfunction or poor maternal vascular adaptation and contribute to the development of preeclampsia. This review aims to comprehensively outline the mechanisms of key innate immune cells including macrophages, neutrophils, natural killer (NK) cells, and innate B1 cells, in normal physiological pregnancy, EOPE and LOPE. The roles of the complement system, syncytiotrophoblast extracellular vesicles and mesenchymal stem cells (MSCs) are also discussed in the context of innate immune system regulation and preeclampsia. The outlined molecular mechanisms, which represent potential therapeutic targets, and associated emerging treatments, are evaluated as treatments for preeclampsia. Therefore, by addressing the current understanding of innate immunity in the pathogenesis of EOPE and LOPE, this review will contribute to the body of research that could lead to the development of better diagnosis, prevention, and treatment strategies. Importantly, it will delineate the differences in the mechanisms of the innate immune system in two different types of preeclampsia, which is necessary for a more personalized approach to the monitoring and treatment of affected women.

Maternal total cell-free DNA in preeclampsia with and without intrauterine growth restriction

Elevation of total cell-free DNA (cfDNA) in patients with preeclampsia is well-known; however, whether this change precedes the onset of symptoms remains inconclusive. Here, we conducted a nested case-control study to determine the elevation of cfDNA levels in women who subsequently developed preeclampsia. Methylated HYP2 (m-HYP2) levels were determined in 68 blood samples collected from women with hypertensive disorders of pregnancy, along with 136 control samples, using real-time quantitative PCR. The measured m-HYP2 levels were converted to multiples of the median (MoM) values for correction of maternal characteristics. The m-HYP2 levels and MoM values in patients with preeclampsia were significantly higher than in controls during the third trimester (P < 0.001, both), whereas those for women who subsequently developed preeclampsia did not differ during the second trimester. However, when patients with preeclampsia were divided based on the onset-time of preeclampsia or 10th percentile birth weight, both values were significantly higher in women who subsequently developed early-onset preeclampsia (P < 0.05, both) and preeclampsia with small-for-gestational-age (SGA) neonate (P < 0.01, both) than controls. These results suggested that total cfDNA levels could be used to predict early-onset preeclampsia or preeclampsia with SGA neonate.

Proteases Activate Pregnancy Neutrophils by a Protease-Activated Receptor 1 Pathway: Epigenetic Implications for Preeclampsia

We tested a novel hypothesis that elevated levels of proteases in the maternal circulation of preeclamptic women activate neutrophils due to their pregnancy-specific expression of protease-activated receptor 1 (PAR-1). Plasma was collected longitudinally from normal pregnant and preeclamptic women and analyzed for MMP-1 and neutrophil elastase. Neutrophils were isolated for culture and confocal microscopy. Omental fat was collected for immunohistochemistry. Circulating proteases were significantly elevated in preeclampsia. Confocal microscopy revealed that tet methylcytosine dioxygenase 2 (TET2), a DNA de-methylase, and p65 subunit of NF-κB were strongly localized to the nucleus of untreated neutrophils of preeclamptic women, but in untreated neutrophils of normal pregnant women they were restricted to the cytosol. Treatment of normal pregnancy neutrophils with proteases activated PAR-1, leading to activation of RhoA kinase (ROCK), which triggered translocation of TET2 and p65 from the cytosol into the nucleus, mimicking the nuclear localization in neutrophils of preeclamptic women. IL-8, an NF-κB-regulated gene, increased in association with TET2 and p65 nuclear localization. Co-treatment with inhibitors of PAR-1 or ROCK prevented nuclear translocation and IL-8 did not increase. Treatment of preeclamptic pregnancy neutrophils with inhibitors emptied the nucleus of TET2 and p65, mimicking the cytosolic localization of normal pregnancy neutrophils. Expression of PAR-1 and TET2 were markedly increased in omental fat vessels and neutrophils of preeclamptic women. We conclude that elevated levels of circulating proteases in preeclamptic women activate neutrophils due to their pregnancy-specific expression of PAR-1 and speculate that TET2 DNA de-methylation plays a role in the inflammatory response.

Differential processing of high-molecular-weight kininogen during normal pregnancy

RATIONALE

Studies identified kininogen as a potential biomarker of preeclampsia, a major cause of adverse maternal outcomes. High-molecular-weight kininogen (HK) and its activated form participate in numerous pathways associated with establishing and maintaining pregnancy. However, dynamic changes in HK and naturally occurring HK-derived peptides during the natural course of pregnancy are largely unknown.

METHODS

Longitudinal serum samples during the course of normal pregnancy (trimesters T1, T2, T3) from 60 pregnant women were analyzed by western blot with an anti-HK antibody. Circulating peptides in longitudinal serum specimens derived from 50 participants were enriched using nanoporous silica thin films. Peptides were identified by liquid chromatography/tandem mass spectrometry (LC/MS/MS) and database searching. Relative quantification was performed using MaxQuant and in-house scripts. Normality was evaluated by either ANOVA or Friedman tests with p < 0.05 for statistical significance.

RESULTS

Western blotting revealed that HK significantly decreased during normal pregnancy (T1 vs T2, p < 0.05; T1 vs T3, p < 0.0001). A 100 kDa intermediate increased during pregnancy (T1 vs T2, p < 0.005; T1 vs T3, p < 0.01). Moreover, the heavy chain (T1 vs T2, p < 0.0001; T1 vs T3, p < 0.0001; T2 vs T3, p < 0.01) and light chain (T1 vs T2, p < 0.0001; T1 vs T3, p < 0.0001; T2 vs T3, p < 0.05) significantly increased during pregnancy. LC/MS/MS analysis identified 180 kininogen-1 peptides, of which 167 mapped to domain 5 (D5). Seventy-three peptides with ten or more complete data sets were included for further analysis. Seventy peptides mapped to D5, and 3, 24, and 43 peptides showed significant decrease, no trend, and significant increase, respectively, during pregnancy.

CONCLUSIONS

This study demonstrates dynamic changes in HK and naturally occurring HK-derived peptides during pregnancy. Our study sheds light on the gestational changes of HK and its peptides for further validation of them as potential biomarkers for pregnancy-related complications.

Common variable immunodeficiency patients display elevated plasma levels of granulocyte activation markers elastase and myeloperoxidase

Common variable immunodeficiency disorders (CVIDs) represent a group of primary immunodeficiency diseases characterized by hypogammaglobulinemia and dysfunctional immune response to invading pathogens. Previous studies have indicated that CVID is associated with microbial translocation and systemic myeloid cell activation.

The goal of this study was to determine whether patients with CVID display elevated systemic levels of markers of granulocyte activation and whether the levels are further influenced by intravenous immunoglobulin (IVIg) infusions. The plasma levels of granulocyte activation markers elastase and myeloperoxidase were determined using enzyme-linked immunosorbent assay (ELISA) in 46 CVID patients and 44 healthy controls. All CVID patients were in a stable state with no apparent acute infection. In addition, granulocyte activation markers’ plasma levels in 24 CVID patients were determined prior to and 1 h following IVIg administration. Neutrophil elastase and myeloperoxidase plasma levels were significantly higher in CVID patients than in healthy controls. Systemic elastase levels were further increased following IVIg administration. In vitro stimulation of 13 CVID patients’ whole blood using IVIg in a therapeutically relevant dose for 2 h resulted in a significant increase in plasma elastase levels compared to unstimulated blood. The data presented here indicate that CVID is associated with chronic granulocytic activation which is further exacerbated by administering IVIg. Increased myeloperoxidase and elastase levels may contribute to associated comorbidities in CVID patients.

The role of neutrophil activation in determining the outcome of pregnancy and modulation by hormones and/or cytokines

Neutrophils are often exclusively considered as a first-line innate immune defence, able to rapidly kill or trap pathogens and causing in case of over-activation tissue damage. In the female reproductive tract, however, the presence and activity of neutrophils seems to be tightly regulated. Major players in orchestrating this regulation are cyclical steroid sex hormones present during the menstrual cycle and pregnancy. This review describes the role of sex hormones in regulating directly or indirectly the functionality of neutrophils, the role of neutrophils during fertilization and pregnancy and in controlling viral, fungal and bacterial infection. This review also discusses the consequence of overt neutrophil activation in pregnancy pathologies.

Resolution of inflammation pathways in preeclampsia-a narrative review

Preeclampsia (PE) is one of the leading causes of maternal morbidity and mortality worldwide. This disease is believed to occur in two stages with placental dysfunction in early pregnancy leading to maternal clinical findings after 20 weeks of gestation, as consequence of systemic inflammation, oxidative stress, and endothelial dysfunction. Much evidence suggests that PE women display an overshooting inflammatory response throughout pregnancy due to an unbalanced regulation of innate and adaptive immune responses. Recently, it has been suggested that dysregulation of endogenous protective pathways might be associated with PE etiopathogenesis. Resolution of inflammation is an active process coordinated by mediators from diverse nature that regulate key cellular events to restore tissue homeostasis. Inadequate or insufficient resolution of inflammation is believed to play an important role in the development of chronic inflammatory diseases, like PE. In this narrative review, we discuss possible pro-resolution pathways that might be compromised in PE women, which could be targets to novel therapeutic strategies in this disease.

Cardiac diastolic function after recovery from pre-eclampsia

BACKGROUND

Pre-eclampsia is associated with significant changes to the cardiovascular system during pregnancy. Eccentric and concentric remodelling of the left ventricle occurs, resulting in impaired contractility and diastolic dysfunction. It is unclear whether these structural and functional changes resolve completely after delivery.

AIMS

The objective of the study was to determine cardiac diastolic function at delivery and one year post-partum in women with severe pre-eclampsia, and to determine possible future cardiovascular risk.

METHODS

This was a descriptive study performed at Steve Biko Academic Hospital, a tertiary referral hospital in Pretoria, South Africa. Ninety-six women with severe preeclampsia and 45 normotensive women with uncomplicated pregnancies were recruited during the delivery admission. Seventy-four (77.1%) women in the pre-eclamptic group were classified as a maternal near miss. Transthoracic Doppler echocardiography was performed at delivery and one year post-partum.

RESULTS

At one year post-partum, women with pre-eclampsia had a higher diastolic blood pressure (p = 0.001) and body mass index (p = 0.02) than women in the normotensive control group. Women with early onset pre-eclampsia requiring delivery prior to 34 weeks' gestation had an increased risk of diastolic dysfunction at one year post-partum (RR 3.41, 95% CI: 1.11-10.5, p = 0.04) and this was irrespective of whether the patient had chronic hypertension or not.

CONCLUSION

Women who develop early-onset pre-eclampsia requiring delivery before 34 weeks are at a significant risk of developing cardiac diastolic dysfunction one year after delivery compared to normotensive women with a history of a low-risk pregnancy.

Correlation of Plasma Neutrophil Elastase Activity and Endogenous Protease Inhibitor Levels with the Severity of Pre-eclampsia

INTRODUCTION

Pre-eclampsia (PE) is a common maternal syndrome characterized by severe systemic inflammatory response including neutrophil activation leading to uncontrolled activity of elastase. The excessive activity of elastase would lead to destroyal of the integrity of endothelial cells and could exacerbate the pathophysiological symptoms in PE. Thus, assessment of NE activity and its control mechanisms would be of relevance in the determination of severity of PE.

AIM

To correlate the activity of plasma NE and its endogenous inhibitors α₁-antitrypsin (α₁-AT) and α₂-macroglobulin (α₂-MG) with severity of PE.

MATERIALS AND METHODS

A comparative study was conducted between normotensive pregnant (n=50) and pre-eclamptic (n=50) women. Serum C-Reactive Protein (CRP) was estimated by rapid latex slide and uric acid by uricase method. Plasma elastase was estimated using succinyl tri- L-alanyl-p-nitroanilide as substrate. Plasma α₁-AT, α₂-MG and NE- α₁-AT complex were quantified by ELISA. ANOVA and Pearson's correlation tests were used to analyze the data. The results were expressed as mean±SD and p-value <0.001 was considered statistically highly significant.

RESULTS

The activity of elastase was increased significantly in severe PE (0.62±0.08) in comparison to normal (0.35±0.10) and mild pre-eclamptic subjects (0.37±0.03). The values of α₁-AT were significantly less in mild (83.94±25.08) and severe PE (68.58+26.39) in comparison to normal (110.26±42.39). There was a significant rise in the levels of α₂-MG in severe PE. However, the complex estimation did not evince any significant changes.

CONCLUSION

The results of the present study indicate a significantly elevated elastase activity, α₂-MG levels and decreased α₁-AT in severe PE patients. The correlation analyses of PE severity parameters with NE, α₁-AT and α₂-MG further support the roles of these molecules in the assessment of severity of PE.

From apelin to exercise: emerging therapies for management of hypertension in pregnancy

Studies over the last couple of decades have provided exciting new insights into mechanisms underlying the pathogenesis of preeclampsia. In addition, several novel and innovative molecules and ideas for management of the syndrome have also come forth. While our basic understanding of the initiating events of preeclampsia continues to be placental ischemia/hypoxia stimulating the release of a variety of factors from the placenta that act on the cardiovascular and renal systems, the number of candidate pathways for intervention continues to increase. Recent studies have identified apelin and its receptor, APJ, as an important contributor to the regulation of cardiovascular and fluid balance that is found to be disrupted in preeclampsia. Likewise, continued studies have revealed a critical role for the complement arm of the innate immune system in placental ischemia induced hypertension and in preeclampsia. Finally, the recent increase in animal models for studying hypertensive disorders of pregnancy has provided opportunities to evaluate the potential role for physical activity and exercise in a more mechanistic fashion. While the exact quantitative importance of the various endothelial and humoral factors that mediate vasoconstriction and elevation of arterial pressure during preeclampsia remains unclear, significant progress has been made. Thus, the goal of this review is to discuss recent efforts towards identifying therapies for hypertension during pregnancy that derive from work exploring the apelinergic system, the complement system as well as the role that exercise and physical activity may play to that end.

Association of first-trimester angiogenic factors with placental histological findings in late-onset preeclampsia

OBJECTIVE

To explore in women with late-onset preeclampsia (PE) the association between maternal levels of angiogenic/antiangiogenic factors in the first trimester of pregnancy and histological findings attributable to placental underperfusion (PUP).

METHODS

A nested case-control cohort study was conducted in 73 women with pregnancies complicated by late-onset PE (>34 weeks at delivery) matched with controls. First trimester uterine artery Doppler (UtA); maternal levels of placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) were retrieved. Placentas were histologically evaluated using a hierarchical and standardized classification system. One-way ANOVA with linear polynomial contrast or linear-by-linear association test was performed to test the hypothesis of a linear association across study groups (controls, PE without PUP and PE with PUP).

RESULTS

In 54 (74%) placentas, 89 placental histological findings qualifying for PUP were found. Across study groups, significant values were observed in maternal levels of decreased PlGF (MoM values: 1.53, 1.41 and 1.37; p < 0.001), increased sFlt-1 (MoM values: 3.11, 3.11 and 3.22; p = 0.002), increased sFlt-1/PlGF ratio (MoM values: 2.3, 2.3 and 2.44; p < 0.001), abnormal UtA Doppler (MoM values: 1, 1.26 and 1.32; p < 0.001), and worse perinatal outcomes in terms of gestational age at delivery, cesarean section for not reassuring fetal status, birth weight and neonatal acidosis.

DISCUSSION

In late-onset PE an imbalance of circulating angiogenic and anti-angiogenic factors already present at 8-10 weeks of pregnancy was associated with histological findings reflecting placental insufficiency. An early first trimester screening by angiogenic factors might help to identify patients with placental involvement among late-onset PE cases.

CONCLUSION

In late-onset preeclampsia, first-trimester uterine Doppler and circulating levels of angiogenic/antiangiogenic factors are associated with placental underperfusion.

Neutrophil Depletion Attenuates Placental Ischemia-Induced Hypertension in the Rat

Preeclampsia is characterized by reduced placental perfusion with placental ischemia and hypertension during pregnancy. Preeclamptic women also exhibit a heightened inflammatory state and greater number of neutrophils in the vasculature compared to normal pregnancy. Since neutrophils are associated with tissue injury and inflammation, we hypothesized that neutrophils are critical to placental ischemia-induced hypertension and fetal demise. Using the reduced uteroplacental perfusion pressure (RUPP) model of placental ischemia-induced hypertension in the rat, we determined the effect of neutrophil depletion on blood pressure and fetal resorptions. Neutrophils were depleted with repeated injections of polyclonal rabbit anti-rat polymorphonuclear leukocyte (PMN) antibody (antiPMN). Rats received either antiPMN or normal rabbit serum (Control) on 13.5, 15.5, 17.5, and 18.5 days post conception (dpc). On 14.5 dpc, rats underwent either Sham surgery or clip placement on ovarian arteries and abdominal aorta to reduce uterine perfusion pressure (RUPP). On 18.5 dpc, carotid arterial catheters were placed and mean arterial pressure (MAP) was measured on 19.5 dpc. Neutrophil-depleted rats had reduced circulating neutrophils from 14.5 to 19.5 dpc compared to Control, as well as decreased neutrophils in lung and placenta on 19.5 dpc. MAP increased in RUPP Control vs Sham Control rats, and neutrophil depletion attenuated this increase in MAP in RUPP rats without any effect on Sham rats. The RUPP-induced increase in fetal resorptions and complement activation product C3a were not affected by neutrophil depletion. Thus, these data are the first to indicate that neutrophils play an important role in RUPP hypertension and that cells of the innate immune system may significantly contribute to pregnancy-induced hypertension.

Placental pathology suggesting that preeclampsia is more than one disease

OBJECTIVE

Our purpose was to evaluate the placental pathology in women with preeclampsia occurring at varying gestational ages.

STUDY DESIGN

This was a secondary analysis of a prospective observational study of placentas from prespecified complicated pregnancies routinely submitted for standardized examination. For this study, a database of placental diagnoses from liveborn singleton gestations without major malformations was linked to a computerized obstetric database. The rates of standardized placental findings including vascular (atherosis, infarction) and nonvascular (hyperplasia) changes were evaluated according to gestational age at diagnosis of preeclampsia.

RESULTS

Between Jan. 1, 2001, and Sept. 30, 2007, a total of 7122 women with pregnancies complicated by preeclampsia were delivered at our hospital. Of these, 1210 (17%) had placental examinations. Within this cohort, 209, 355, and 646 women were diagnosed with preeclampsia at gestations of 24(0/67) to 33(6/7), 34(0/7) to 36(6/7), and 37(0/7) weeks or longer, respectively. Placental findings revealed hypoplasia was significantly associated with preeclampsia early in the third trimester, and histological evidence of placental vascular lesions was significantly increased at gestations of 24(0/67) to 33(6/7) weeks (53%) compared with 34% and 26% at 34(0/7) to 36(6/7) and 37 weeks or longer, respectively (P < .001).

CONCLUSION

The placentas of women with preeclampsia onset before 34 weeks' gestation were significantly different from those with preeclampsia at term. The former group demonstrated placental findings predominantly consistent with insufficiency because of vascular abnormalities. Such differing placental findings support the hypothesis that preeclampsia is a different disease, depending on the gestational age at diagnosis.

Neutrophil NETs in reproduction: from infertility to preeclampsia and the possibility of fetal loss

The intention of this review is to provide an overview of the potential role of neutrophil extracellular traps (NETs) in mammalian reproduction. Neutrophil NETs appear to be involved in various stages of the reproductive cycle, starting with fertility and possibly ending with fetal loss. The first suggestion that NETs may play a role in pregnancy-related disorders was in preeclampsia, where vast numbers were detected in the intervillous space of affected placentae. The induction of NETosis involved an auto-inflammatory component, mediated by the increased release of placental micro-debris in preeclampsia. This report was the first indicating that NETs may be associated with a human pathology not involving infection. Subsequently, NETs have since then been implicated in bovine or equine infertility, in that semen may become entrapped in the female reproductive tract during their passage to the oocyte. In this instance interesting species-specific differences are apparent, in that equine sperm evade entrapment via expression of a DNAse-like molecule, whereas highly motile bovine sperm, once free from seminal plasma (SP) that promotes interaction with neutrophils, appear impervious to NETs entrapment. Although still in the realm of speculation it is plausible that NETs may be involved in recurrent fetal loss mediated by anti-phospholipid antibodies, or perhaps even in fetal abortion triggered by infections with microorganisms such as L. monocytogenes or B. abortus.

Dynamic proteome in enigmatic preeclampsia: an account of molecular mechanisms and biomarker discovery

The coevolution of genomics and proteomics has led to advancements in the field of diagnosis and molecular mechanisms of disease. Proteomics is now stepping into the field of obstetrics, where early diagnosis of pregnancy complication such as preeclampsia (PE) is imperative. PE is a multifactorial disease characterized by hypertension with proteinuria, which is a leading cause of maternal and neonatal morbidity and mortality occurring in 5-7% of pregnancies worldwide. This review discusses the probable molecular mechanisms that lead to PE and summarizes the proteomics research carried out in understanding the pathogenicity of PE, and for identifying the candidate biomarker for diagnosis of the disease.

Inflammatory disturbances in preeclampsia: relationship between maternal and umbilical cord blood

Preeclampsia (PE) is one of the main causes of maternal and fetal mortality and morbidity. PE is associated with an inflammatory state and with oxidative stress, in maternal circulation. Our aim was to evaluate and compare the levels of oxidative stress and inflammatory markers in maternal and umbilical cord blood (UCB), in normal and PE pregnancies. We measured acute-phase proteins (CRP and α1-antitrypsin), proinflammatory cytokines (IL-6 and TNF-α), leukocyte activation (elastase, lactoferrin, sL-selectin, sVCAM, sPECAM), total antioxidant status (TAS), thiobarbituric acid reactive substances (TBARS), and uric acid levels. We studied 42 healthy pregnant women, 46 PE women, and their neonates. The concentrations of IL-6, TNF-α, α1-antitrypsin, CRP, sVCAM, uric acid, and TBARS were significantly higher, and sL-selectin was significantly lower in PE pregnant women as compared with normotensive pregnant women. In newborns uric acid, α1-antitrypsin, and CRP values were significantly higher in PE; leukocyte count, sL-selectin, lactoferrin, and the ratio elastase/α1-antitrypsin were significantly lower. Our data suggest that PE pregnancy is associated with an enhanced maternal inflammatory condition, which is reflected in fetal circulation. This enhanced inflammatory state seems to be related to endothelial dysfunction and increased cytokine synthesis, rather than with neutrophil activation.

Placental lesions associated with maternal underperfusion are more frequent in early-onset than in late-onset preeclampsia

OBJECTIVE

Preeclampsia (PE) has been classified into early- and late-onset disease. These two phenotypic variants of PE have been proposed to have a different pathophysiology. However, the gestational age cut-off to define "early" vs. "late" PE has varied among studies. The objective of this investigation was to determine the prevalence of lesions consistent with maternal underperfusion of the placenta in patients with PE as a function of gestational age.

STUDY DESIGN

A nested case-control study of 8307 singleton pregnant women who deliver after 20 weeks of gestation was constructed based on a cohort. Cases were defined as those with PE (n=910); controls were pregnant women who did not have a hypertensive disorder in pregnancy (n=7397). The frequency of maternal underperfusion of the placenta (according to the criteria of the Society for Pediatric Pathology) was compared between the two groups. Logistic regression was used for analysis. Estimated relative risks (RRs) were calculated from odds ratios.

RESULTS

1) The prevalence of lesions consistent with maternal underperfusion was higher in patients with PE than in the control group [43.3% vs. 15.9%, unadjusted odds ratio 4.0 (95% CI 3.5-4.7); P<0.001]; 2) the estimated RR of maternal underperfusion lesions in PE was higher than in the control group [RR=2.8 (95% CI 2.5-3.0)]; 3) the lower the gestational age at delivery, the higher the RR for these lesions; 4) early-onset PE, regardless of the gestational age used to define it (<32, 33, 34, 35 or 37 weeks) had a significantly higher frequency of placental lesions consistent with maternal underperfusion than late-onset PE (P<0.001 for all).

CONCLUSIONS

1) The earlier the gestational age of preeclampsia at delivery, the higher the frequency of placental lesions consistent with maternal underperfusion; 2) our data suggest that demonstrable placental involvement as determined by pathologic examination differs in early- and late-onset preeclampsia; and 3) this phenomenon appears to be a continuum, and we could not identify a clear and unambiguous gestational age at which lesions consistent with underperfusion would not be present.

Microparticles of pregnant women and preeclamptic patients activate endothelial cells in the presence of monocytes

PROBLEM

Preeclampsia is a pregnancy-specific disorder that may result from an adverse maternal response to circulating placenta-derived factors, causing a systemic inflammation including endothelial activation. Plasma from preeclamptic patients was shown to induce endothelial activation in the presence of monocytes. We investigated whether microparticles (MP) are the plasma factors causing this activation of endothelial cells.

METHOD OF STUDY

Monocultures and co-cultures of monocytes and endothelial cells were incubated with plasma, MP-poor plasma or isolated MP from non-pregnant and pregnant women and preeclamptic patients (each n = 8). ICAM-1 expression was analyzed with flow cytometry.

RESULTS

The expression of ICAM-1 was significantly increased in monocytes and endothelial cells in co-cultures after the addition of isolated MP from preeclamptic patients (P = 0.017) and to a lesser extent in pregnant women (P = 0.012) compared to non-pregnant controls.

CONCLUSIONS

Microparticles from preeclamptic patients activate endothelial cells in the presence of monocytes. Whether all MP have the same effect on monocytes and endothelial cells or only a specific subgroup is the focus of future research.

Implication of umbilical cord in preeclampsia

OBJECTIVES

To investigate the role of biochemical changes in the umbilical cord and placenta in developing preeclampsia (PE).

SUBJECTS AND METHODS

Thirty women with PE and 15 healthy pregnant women as controls were enrolled in this study. Vascular endothelial growth factor (VEGF), soluble vascular endothelial growth factor receptor 1 (sVEGFR-1), platelet-derived endothelial cell growth factor (PD-ECGF), neutrophil elastase and nitric oxide (NO) were measured.

RESULTS

Both serum (maternal and fetal) and tissue (placenta and umbilical cord) levels of VEGF, sVEGFR-1, PD-ECGF and neutrophil elastase were significantly increased, whereas NO was significantly decreased (except placental tissue showed no changes) in preeclamptic patients. The cord serum level of PD-ECGF was significantly higher in severe PE compared to mild PE and normal pregnant women. The placental and cord tissue levels of PD-ECGF and neutrophil elastase were significantly higher in severe PE, while the cord tissue level of NO was significantly lower in severe PE.

CONCLUSION

Our data showed that umbilical cord vessels and stroma can serve as an additional source of vasoactive and angiogenic substances that contribute to the biochemical changes occurring in PE.

Vascular and cellular calcium in normal and hypertensive pregnancy

Normal pregnancy is associated with significant hemodynamic changes in the cardiovascular system in order to meet the metabolic demands of mother and fetus. These changes include increased cardiac output, decreased vascular resistance, and vascular remodeling in the uterine and systemic circulation. Preeclampsia (PE) is a major complication of pregnancy characterized by proteinuria and hypertension. Several risk factors have been implicated in the pathogenesis of PE including genetic and dietary factors. Ca2+ is an essential dietary element and an important regulator of many cellular processes including vascular function. The importance of adequate dietary Ca2+ intake during pregnancy is supported by many studies. Pregnancy-associated changes in Ca2+ metabolism and plasma Ca2+ have been observed. During pregnancy, changes in intracellular free Ca2+ concentration ([Ca2+](i)) have been described in red blood cells, platelets and immune cells. Also, during pregnancy, an increase in [Ca2+](i) in endothelial cells (EC) stimulates the production of vasodilator substances such as nitric oxide and prostacyclin. Normal pregnancy is also associated with decreased vascular smooth muscle (VSM) [Ca2+](i) and possibly the Ca2+-sensitization pathways of VSM contraction including protein kinase C, Rho-kinase, and mitogen-activated protein kinase. Ca2+-dependent matrix metalloproteinases could also promote extracellular matrix degradation and vascular remodeling during pregnancy. Disruption in the balance between dietary, plasma and vascular cell Ca2+ may be responsible for some of the manifestation of PE including procoagulation, decreased vasodilation, and increased vasoconstriction and vascular resistance. The potential benefits of Ca2+ supplements during pregnancy, and the use of modulators of vascular Ca2+ to reduce the manifestations of PE in susceptible women remain an important area for experimental and clinical research.

Aberrant processing of plasma vitronectin and high-molecular-weight kininogen precedes the onset of preeclampsia

To date, there is no reliable test to identify women in early pregnancy at risk of developing preeclampsia. Difference gel electrophoresis (DIGE) identified the plasma proteins vitronectin (VN) and high-molecular-weight kininogen (HK) in association with preeclampsia. In a longitudinal proteomics study, the plasma of preeclamptic patients (n = 6) was compared to healthy control participants (n = 6) before the onset of preeclampsia (week 20) and at the time of presentation with clinical disease (weeks 33-36). The 75-kd single-chain VN molecule increased 1.6- to 1.9-fold in preeclampsia, whereas the 65-kd moiety of the 2-chain VN molecule decreased 1.5- to 1.7-fold compared to healthy controls (P < .05). Immunoblots revealed differences in proteolytic processing of VN and/or HK in women who develop preeclampsia or preeclampsia further complicated by small-for-gestational-age. Vitronectin and HK may prove to be useful as early markers of fibrinolytic activity and neutrophil activation, which are known to be associated with preeclampsia.

Leukocyte activation and circulating leukocyte-derived microparticles in preeclampsia

PROBLEM

Preeclampsia shows characteristics of an inflammatory disease including leukocyte activation. Analyses of leukocyte-derived microparticles (MP) and mRNA expression of inflammation-related genes in leukocytes may establish which subgroups of leukocytes contribute to the development of preeclampsia.

METHOD OF STUDY

Blood samples were obtained from preeclamptic patients, normotensive pregnant and non-pregnant controls. sL-selectin and elastase were measured by ELISA. mRNA was isolated from leukocytes and gene expression was determined by multiplex ligation-dependent probe amplification (MLPA). MP were characterized by flow cytometry.

RESULTS

Altered concentrations of sL-selectin and elastase confirmed leukocyte activation in preeclampsia. These leukocytes showed up-regulation of Nuclear Factor of Kappa light chain gene enhancer in B cells inhibitor (NFkappaB-1A) and cyclin-dependent kinase inhibitor (CDKN)-1A compared with normotensive pregnant women. Interleukin-1 Receptor Antagonist (IL-1RA) and tumor necrosis factor (TNF)-R1 were increased compared with those in non-pregnant controls. Monocyte-derived MP were elevated in preeclamptic patients compared with pregnant women. The numbers of cytotoxic T-cell-derived and granulocyte-derived MP were elevated compared with those of non-pregnant women.

CONCLUSION

Leukocytes are activated in preeclampsia. A pro-inflammatory gene expression profile is not prominent, although differences in mRNA expression can be detected. Increased levels of particular subsets of leukocyte-derived MP reflect activation of their parental cells in preeclampsia.