Increased Neutrophil Activation and Plasma DNA Levels in Patients with Pre-Eclampsia

Placental neutrophil reverse trans-migration and maternal serum neutrophil extracellular trap expression in HIV infection co-morbid pre-eclampsia in women of African ancestry

Neutrophil extracellular traps (NETs) and placental neutrophil reverse transmigration (r-TM) are implicated in the pathogenesis of pre-eclampsia (PE). However, the role of the comorbidity of PE and human immunodeficiency virus (HIV) infection in placental neutrophil r-TM and serum NETs remains unknown. Human placental tissue (n = 160) and serum (n = 80) samples were obtained post-ethical approval and divided by pregnancy type and HIV status and across the study population. Immunohistochemistry and morphometry were performed to localize and quantify junctional adhesion molecule-C (JAM-C) expression as an inverse marker of neutrophil r-TM within placental villi. An enzyme-linked immunosorbent assay (ELISA) was performed to quantify the concentration of citrullinated histone H3 (cit-H3) as a marker of NETs. GraphPad Prism (version 8.0.2) was used to compare the results, and a p value of p < 0.05 was considered statistically significant. The localization of JAM-C was observed on the syncytiotrophoblasts (STBs) and endothelial cells of placental villi. The immunoexpression of JAM-C was elevated in PE vs. normotensive (N) placentae. In the exchange villi, JAM-C immunoexpression was higher in the N+ve vs. N-ve group. However, in PE comorbid HIV infection, JAM-C expression was lower in the PE+ve vs. PE-ve group. Citrullinated histone-H3 concentration was lower in the N+ve vs. N-ve group but elevated in early-onset PE (EOPE)+ve vs. late-onset PE (LOPE)+ve group. These results indicate that PE and HIV-infected placentae individually express elevated JAM-C, manifesting in less neutrophil r-TM. However, in exchange villi of PE comorbid with HIV infection reduced JAM-C enhances neutrophil r-TM, thus supporting the synergistic effect of PE comorbid with HIV.

Placental Drug Delivery to Treat Pre-Eclampsia and Fetal Growth Restriction

Pre-eclampsia and fetal growth restriction (FGR) continue to cause unacceptably high levels of morbidity and mortality, despite significant pharmaceutical and technological advances in other disease areas. The recent pandemic has also impacted obstetric care, as COVID-19 infection increases the risk of poor pregnancy outcomes. This review explores the reasons why it lacks effective drug treatments for the placental dysfunction that underlies many common obstetric conditions and describes how nanomedicines and targeted drug delivery approaches may provide the solution to the current drug drought. The ever-increasing range of biocompatible nanoparticle formulations available is now making it possible to selectively deliver drugs to uterine and placental tissues and dramatically limit fetal drug transfer. Formulations that are refractory to placental uptake offer the possibility of retaining drugs within the maternal circulation, allowing pregnant individuals to take medicines previously considered too harmful to the developing baby. Liposomes, ionizable lipid nanoparticles, polymeric nanoparticles, and adenoviral vectors have all been used to create efficacious drug delivery systems for use in pregnancy, although each approach offers distinct advantages and limitations. It is imperative that recent advances continue to be built upon and that there is an overdue investment of intellectual and financial capital in this field.

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.

Maternal gut microbiota in the health of mothers and offspring: from the perspective of immunology

Due to the physiological alteration during pregnancy, maternal gut microbiota changes following the metabolic processes. Recent studies have revealed that maternal gut microbiota is closely associated with the immune microenvironment in utero during pregnancy and plays a vital role in specific pregnancy complications, including preeclampsia, gestational diabetes, preterm birth and recurrent miscarriages. Some other evidence has also shown that aberrant maternal gut microbiota increases the risk of various diseases in the offspring, such as allergic and neurodevelopmental disorders, through the immune alignment between mother and fetus and the possible intrauterine microbiota. Probiotics and the high-fiber diet are effective inventions to prevent mothers and fetuses from diseases. In this review, we summarize the role of maternal gut microbiota in the development of pregnancy complications and the health condition of future generations from the perspective of immunology, which may provide new therapeutic strategies for the health management of mothers and offspring.

Characterizing immune variation and diagnostic indicators of preeclampsia by single-cell RNA sequencing and machine learning

Preeclampsia is a multifactorial and heterogeneous complication of pregnancy. Here, we utilize single-cell RNA sequencing to dissect the involvement of circulating immune cells in preeclampsia. Our findings reveal downregulation of immune response in lymphocyte subsets in preeclampsia, such as reduction in natural killer cells and cytotoxic genes expression, and expansion of regulatory T cells. But the activation of naïve T cell and monocyte subsets, as well as increased MHC-II-mediated pathway in antigen-presenting cells were still observed in preeclampsia. Notably, we identified key monocyte subsets in preeclampsia, with significantly increased expression of angiogenesis pathways and pro-inflammatory S100 family genes in VCAN+ monocytes and IFN+ non-classical monocytes. Furthermore, four cell-type-specific machine-learning models have been developed to identify potential diagnostic indicators of preeclampsia. Collectively, our study demonstrates transcriptomic alternations of circulating immune cells and identifies immune components that could be involved in pathophysiology of preeclampsia.

Obesity Correlates with Chronic Inflammation of the Innate Immune System in Preeclampsia and HELLP Syndrome during Pregnancy

HELLP syndrome is characterized by hemolysis, elevated liver enzymes, and a low platelet count and poses an increased risk to the pregnant woman and the unborn child. Individual risk factors such as obesity may alter immunocompetence and influence the course of preeclampsia (PE) or HELLP syndrome. Blood samples were collected from 21 pregnant women (7 healthy, 6 with PE, and 8 with HELLP syndrome) and polymorphonuclear neutrophils (PMNs) were subsequently isolated. Production of radical oxygen species (ROS), cell movement, and NETosis were assessed by live-cell imaging. Surface protein expression and oxidative burst were analyzed by flow cytometry. PE and HELLP patients had significantly higher BMI compared to the healthy control group. Depending on the expression of CD11b, CD62L, and CD66b on PMNs, a surface protein activation sum scale (SPASS) was calculated. PMNs from patients with high SPASS values showed prolonged and more targeted migration with delayed ROS production and NETosis. Obesity is associated with a chronic inflammatory state, which in combination with immunological triggers during pregnancy could modulate PMN functions. Pregnant women with higher BMI tend to have higher SPASS values, indicating activation of the innate immune system that could co-trigger PE or HELLP syndrome.

A Narrative Review of Parameters Influencing Preeclampsia in the COVID-19 Era

The COVID-19 outbreak has emerged as one of the most profound medical events of the 21st century, leaving an indelible impact on a global scale. The widespread prevalence causing significant illness and death needs collaborative and inventive efforts to deal with this challenge. One of the particular subset of the general population that had endured a significant impact was the pregnant population. A key complication of pregnancy seen in patients with a COVID-19 infection was the increased risk of developing preeclampsia. The angiotensin-converting enzyme 2 (ACE2) receptor is an important part of the renin-angiotensin system, which has been implicated in the control of blood flow and also is a key receptor in the pathogenesis of the multitude of symptoms of COVID-19. This study aimed to evaluate the psychiatric, hematological, neurological, and social factors influenced by the COVID-19 virus and its subsequent effect on the development of preeclampsia. Increased rates of anxiety and depression were seen globally during the COVID-19 pandemic and due to the following physiological response of anxiety and depression, elevated blood pressure levels and development of preeclampsia were noted. Neurological factors such as the development of posterior reversible encephalopathy syndrome and its relationship between COVID-19 and preeclampsia were also strongly observed. The observation suggested biomarkers such as serum neurofilament light may be used as a screening tool to stratify the severity of preeclampsia. Hematological parameters observed were most notable for the presence of thrombocytopenia, which itself is a marker of the severity of preeclampsia. The numerous effects of COVID-19 on preeclampsia have proven to have a tremendous impact on the healthcare burden. Careful analysis and prevention strategies, if implemented, will contribute to reducing the morbidity and mortality of patients with preeclampsia and COVID-19 infections.

Placental Inflammation Leads to Abnormal Embryonic Heart Development

BACKGROUND

Placental heart development and embryonic heart development occur in parallel, and these organs have been proposed to exert reciprocal regulation during gestation. Poor placentation has been associated with congenital heart disease, an important cause of infant mortality. However, the mechanisms by which altered placental development can lead to congenital heart disease remain unresolved.

METHODS

In this study, we use an in vivo neutrophil-driven placental inflammation model through antibody depletion of maternal circulating neutrophils at key stages during time-mated murine pregnancy: embryonic days 4.5 and 7.5. Pregnant mice were culled at embryonic day 14.5 to assess placental and embryonic heart development. A combination of flow cytometry, histology, and bulk RNA sequencing was used to assess placental immune cell composition and tissue architecture. We also used flow cytometry and single-cell sequencing to assess embryonic cardiac immune cells at embryonic day 14.5 and histology and gene analyses to investigate embryonic heart structure and development. In some cases, offspring were culled at postnatal days 5 and 28 to assess any postnatal cardiac changes in immune cells, structure, and cardiac function, as measured by echocardiography.

RESULTS

In the present study, we show that neutrophil-driven placental inflammation leads to inadequate placental development and loss of barrier function. Consequently, placental inflammatory monocytes of maternal origin become capable of migration to the embryonic heart and alter the normal composition of resident cardiac macrophages and cardiac tissue structure. This cardiac impairment continues into postnatal life, hindering normal tissue architecture and function. Last, we show that tempering placental inflammation can prevent this fetal cardiac defect and is sufficient to promote normal cardiac function in postnatal life.

CONCLUSIONS

Taken together, these observations provide a mechanistic paradigm whereby neutrophil-driven inflammation in pregnancy can preclude normal embryonic heart development as a direct consequence of poor placental development, which has major implications on cardiac function into adult life.

Vital NETosis vs. suicidal NETosis during normal pregnancy and preeclampsia

Background: NETosis occurs in the context of infection or inflammation and results in the expulsion of decondensed DNA filaments called NETs (Neutrophil Extracellular Traps) into the extracellular environment. NETosis activates coagulation and contributes to the thrombotic risk of inflammatory diseases. To date, two mechanisms of NETosis have been identified: suicidal NETosis, in which neutrophils die after expelling the filaments; and vital NETosis, in which expulsion appears without altering the membrane. Human pregnancy is associated with a mild pro-inflammatory state, which is increased in the event of complications such as preeclampsia (PE). NETosis has been observed in these situations, but the mechanism of its production has not yet been studied. The aim of our study was to evaluate the balance of vital vs. suicidal NETosis in normal pregnancy and in PE. Patients/Methods: Neutrophils from healthy volunteers were stimulated with plasma from normal pregnancies (n = 13) and from women developing preeclampsia (n = 13). Immunofluorescent labelling was performed to determine the percentages and origin of NETs in both groups. Inhibition with suicidal or vital NETosis inhibitors was also performed to validate our results. Results: We found a significant increase in NETs in women with PE compared to women with normal pregnancies. We showed that vital and non-vital NETosis are present in normal and preeclamptic pregnancies. We demonstrated that the higher proportion of NETs observed in PE was due to non-vital NETosis whose main component is represented by suicidal NETosis. Discussion: These results suggest the important part of non-vital NETosis in the pathophysiology of PE.

Neutrophil-to-lymphocyte ratio (NLR) as a predictive index for liver and coagulation dysfunction in preeclampsia patients

BACKGROUND

Pre-eclampsia (PE) is a pregnancy disorder that is related to an enhanced immune response. Immune cell characteristics such as neutrophil or monocyte to lymphocyte ratios (NLR, MLR) are known to be related to kidney and liver dysfunction in hypertensive patients. Here, we aimed to analyze the correlations between NLR, MLR and platelet to lymphocyte ratio (PLR) and liver, renal and coagulation functional parameters and the impacts of these immune cell profiles to the prognostic significance in PE patients.

METHODS

Pre-delivery hematological and biochemical parameters of 320 first-time pregnant women registered at the Obstetrics Department of Yanbian University Hospital from 2016 to 2019 were analyzed retrospectively. Patients were divided into normal pregnancy (normal, n = 161), mild PE (mPE, n = 28) and severe PE (sPE, n = 131) groups according to diagnostic criteria. Pearson correlation analysis were performed and area under the curve (AUC) were conducted for the diagnostic values of NLR, MLR and PLR. Results were validated with data from the Department of Obstetrics and Gynecology of Seoul National University Hospital (SNUH).

RESULTS

Kidney functional indexes were adversative in mPE and sPE and liver and coagulation indexes were worse in sPE compared to normal groups. Among immune cells, lymphocytes were increased in mPE and sPE patients, resulted in reduced NLR, MLR and PLR in PE groups, more significant difference were shown in sPE. NLR and PLR were associated with CREA and/or BUN negatively and positive associations were observed with total protein (TP) and albumin (ALB) in sPE. Only NLR showed positive associations with coagulation indexes (PT and APTT) in sPE. AUC analysis for NLR, MLR and PLR were 0.700, 0.656, 0.643, respectively, and NLR < 3.7 predicted hypertension (95% CI in all participants: 0.647-0.749, p < 0.001). Blood pressure, liver, kidney and coagulation indexes were worse at cut off value (NLR < 3.7), and this was validated with the data from SNUH.

CONCLUSION

NLR could be used as an independent predictor of liver and coagulation dysfunction in PE patients. Our results may provide non-invasive and efficient way of the risk assessment among PE patients.

Combining curcumin and aspirin ameliorates preeclampsia-like symptoms by inhibiting the placental TLR4/NF-κB signaling pathway in rats

AIM

Preeclampsia (PE) is a common medical complication of pregnancy characterized by high blood pressure and proteinuria after the 20th gestational week. This study aimed to investigate the potency of the combination of curcumin and aspirin in the treatment of PE and explore the underlying mechanisms.

MATERIAL AND METHODS

The PE model was constructed in female rats by administering 0.5 mg/mL N-nitro-L-arginine methyl ester from gestational days (GDs) 6 to 16. The pregnant female rats were divided into five groups according to the drug treatment. The curcumin or aspirin was given to the rats by tail vein injection (0.36 mg/kg) or gavage treatment (1.5 mg/kg BW/day) from GD4 to GD18.

RESULTS

Treatment with curcumin and aspirin combination significantly reduced the systolic blood pressure and proteinuria in the PE rats. Meanwhile, in comparison to the PE rats treated with single-dose curcumin or aspirin, the rats treated with combined curcumin and aspirin showed significantly decreased sFlt-1, increased placental growth factor, and alleviated oxidative stress in both blood and placental tissues, which are abnormal in no-treated PE rats. Furthermore, dramatically decreased inflammatory cytokines secretion and TLR4 and NF-κB p65 expression in placental tissues were also observed in the PE rats with combined treatment compared to those of no-treated, signal-dose curcumin or aspirin-treated PE rats.

CONCLUSIONS

Our results suggested that the combined treatment of curcumin and aspirin significantly ameliorates the symptoms of PE in rats, which is most likely due to the inhibition of the placental TLR4/NF-κB p65 signaling pathway.

Neutrophil count is a useful marker to predict the severity of preeclampsia

BACKGROUND

At present, pre-eclampsia is a growing concern and still a diagnostic challenge for obstetricians.

AIMS

This study aimed to evaluate whether the relationship of second trimester of pregnancy neutrophil count differed among pregnancies with mild preeclampsia, severe preeclampsia, and healthy status and explore whether or not neutrophil count in the second trimester of pregnancy would be useful as new predictors of subsequent preeclampsia.

PATIENTS AND METHODS

This study involved 933 pregnancies from 1 January 2018 to 30 January 2021, comprising 396 healthy pregnancies, 222 pregnancies with mild preeclampsia, and 315 pregnancies with severe preeclampsia. The relationship between preeclampsia and neutrophil count was analyzed by multiple logistic regression. In addition, maternal placental tissues of three groups were immunohistochemically stained for myeloperoxidase (MPO).

RESULTS

Neutrophil count was significantly higher in pregnancies with preeclampsia (including pregnancies with mild and severe preeclampsia) than that in healthy pregnancies. The neutrophil count level was prominently higher in patients with severe preeclampsia compared with those with mild preeclampsia (p < .001). The neutrophil count level was significantly positively associated with preeclampsia after adjusting for gestational week at time of blood sampling, BMI, and age (β:1.23; 95%CI:1.09-1.36; p < .0001). In addition, MPO expressions of placental tissues in preeclamptic groups were significantly increased than these in healthy pregnant controls (p < .05).

CONCLUSIONS

Increased neutrophil count in the second trimester of pregnancy was significantly positively associated with preeclampsia. Hence, neutrophil count plays a role in predicting the severity of preeclampsia. At the same time, it may be an independent predictor of subsequent preeclampsia.Abbreviations: BMI: body mass index; MPO: myeloperoxidase.

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.

Neutrophil extracellular traps promote gastric cancer metastasis by inducing epithelial‑mesenchymal transition

The risks of tumor recurrence following the successful resection of the primary tumor have been known for decades; however, the precise mechanisms underlying treatment failures remain unknown. The formation of neutrophil extracellular traps (NETs) has increasingly been demonstrated to be associated with thrombi formation in cancer patients, as well as with the development and metastasis of cancer. The present study demonstrated that the level of peripheral blood NETs in patients with gastric cancer (GC) was associated with tumor progression, and patients with stage III/IV disease exhibited significant differences compared with the healthy controls and patients with stage I/II disease, which may be associated with an increased risk of metastasis. In addition, plasma from patients with stage III/IV GC was more prone to stimulate neutrophils to form NETs; thus, it was hypothesized that the formation of NETs may be affected by the tumor microenvironment. A higher deposition of NETs in GC tissues compared with normal resection margins was also identified. In vitro, following treatment with phorbol myristate acetate, which promotes the formation of NETs, or with DNAse-1/GSK-484, which inhibits the formation of NETs, it was found that the tumor migratory ability was altered; however, no significant changes were observed in cell proliferation and cell cycle progression. Epithelial-mesenchymal transition (EMT) is a key event associated with dissemination and metastasis in GC pathogenesis. Finally, the present study demonstrated that NETs promote a more aggressive mesenchymal phenotype and promote the progression of GC in vitro and in vivo. On the whole, to the best of our knowledge, the present study reports a previously unknown role of NETs in the regulation of GC, which is associated with EMT and migration. Therefore, targeting NETs may prove to be therapeutically beneficial.

NETosis Markers in Pregnancy: Effects Differ According to Histone Subtypes

NETosis is an innate immune response occurring after infection or inflammation: activated neutrophils expel decondensed DNA in complex with histones into the extracellular environment in a controlled manner. It activates coagulation and fuels the risk of thrombosis. Human pregnancy is associated with a mild proinflammatory state characterized by circulatory neutrophil activation which is further increased in complicated pregnancies, placenta-mediated complications being associated with an increased thrombotic risk. This aberrant activation leads to an increased release of nucleosomes in the blood flow. The aim of our study was to initially quantify nucleosome-bound histones in normal pregnancy and in placenta-mediated complication counterpart. We analyzed the role of histones on extravillous trophoblast function. Circulating nucleosome-bound histones H3 (Nu.QH3.1, Nu.QH3PanCit, Nu.QH3K27me3) and H4 (Nu.QH4K16Ac) were increased in complicated pregnancies. In vitro using the extravillous cell line HTR-8/SVNeo, we observed that free recombinant H2B, H3, and H4 inhibited migration in wound healing assay, but only H3 also blocked invasion in Matrigel-coated Transwell experiments. H3 and H4 also induced apoptosis, whereas H2B did not. Finally, the negative effects of H3 on invasion and apoptosis could be restored with enoxaparin, a low-molecular-weight heparin (LMWH), but not with aspirin. Different circulating nucleosome-bound histones are increased in complicated pregnancy and this would affect migration, invasion, and induce apoptosis of extravillous trophoblasts. Histones might be part of the link between the risk of thrombosis and pregnancy complications, with an effect of LMWH on both.

Hypothesis: Alpha-1-antitrypsin is a promising treatment option for COVID-19

No definitive treatment for COVID-19 exists although promising results have been reported with remdesivir and glucocorticoids. Short of a truly effective preventive or curative vaccine against SARS-CoV-2, it is becoming increasingly clear that multiple pathophysiologic processes seen with COVID-19 as well as SARS-CoV-2 itself should be targeted. Because alpha-1-antitrypsin (AAT) embraces a panoply of biologic activities that may antagonize several pathophysiologic mechanisms induced by SARS-CoV-2, we hypothesize that this naturally occurring molecule is a promising agent to ameliorate COVID-19. We posit at least seven different mechanisms by which AAT may alleviate COVID-19. First, AAT is a serine protease inhibitor (SERPIN) shown to inhibit TMPRSS-2, the host serine protease that cleaves the spike protein of SARS-CoV-2, a necessary preparatory step for the virus to bind its cell surface receptor ACE2 to gain intracellular entry. Second, AAT has anti-viral activity against other RNA viruses HIV and influenza as well as induces autophagy, a known host effector mechanism against MERS-CoV, a related coronavirus that causes the Middle East Respiratory Syndrome. Third, AAT has potent anti-inflammatory properties, in part through inhibiting both nuclear factor-kappa B (NFκB) activation and ADAM17 (also known as tumor necrosis factor-alpha converting enzyme), and thus may dampen the hyper-inflammatory response of COVID-19. Fourth, AAT inhibits neutrophil elastase, a serine protease that helps recruit potentially injurious neutrophils and implicated in acute lung injury. AAT inhibition of ADAM17 also prevents shedding of ACE2 and hence may preserve ACE2 inhibition of bradykinin, reducing the ability of bradykinin to cause a capillary leak in COVID-19. Fifth, AAT inhibits thrombin, and venous thromboembolism and in situ microthrombi and macrothrombi are increasingly implicated in COVID-19. Sixth, AAT inhibition of elastase can antagonize the formation of neutrophil extracellular traps (NETs), a complex extracellular structure comprised of neutrophil-derived DNA, histones, and proteases, and implicated in the immunothrombosis of COVID-19; indeed, AAT has been shown to change the shape and adherence of non-COVID-19-related NETs. Seventh, AAT inhibition of endothelial cell apoptosis may limit the endothelial injury linked to severe COVID-19-associated acute lung injury, multi-organ dysfunction, and pre-eclampsia-like syndrome seen in gravid women. Furthermore, because both NETs formation and the presence of anti-phospholipid antibodies are increased in both COVID-19 and non-COVID pre-eclampsia, it suggests a similar vascular pathogenesis in both disorders. As a final point, AAT has an excellent safety profile when administered to patients with AAT deficiency and is dosed intravenously once weekly but also comes in an inhaled preparation. Thus, AAT is an appealing drug candidate to treat COVID-19 and should be studied.

Placenta-mediated complications: Nucleosomes and free DNA concentrations differ depending on subtypes

BACKGROUND

Placenta-mediated pregnancy complications generate short- and long-term adverse medical outcomes for both the mother and the fetus. Nucleosomes and free DNA (fDNA) have been described in patients suffering from a wide range of inflammatory conditions.

OBJECTIVE

The objective of our study was to compare nucleosomes and fDNA circulating levels during pregnancy and particularly in women developing a placenta-mediated complication according to the subtype (preeclampsia or intrauterine growth restriction) (NCT01736826).

PATIENTS/METHODS

A total of 115 women were prospectively included in the study across three groups: 30 healthy non-pregnant women, 50 with normal pregnancy, and 35 with a complicated pregnancy. Blood samples were taken up to every 4 weeks for several women with normal pregnancy and nucleosomes and fDNA were quantified using enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, respectively.

RESULTS

We show that nucleosomes and fDNA concentrations significantly increase during normal pregnancy, with concentrations at delivery differing between the two groups. Interestingly, we show that concentrations differ according to the type of placenta-mediated complications, with higher levels in preeclampsia compared to intrauterine growth restriction.

CONCLUSIONS

These data suggest that nucleosomes and fDNA may be additional actors participating in placenta-mediated pregnancy complications.

The Role of Neutrophils and Their Extracellular Traps in the Synergy of Pre-eclampsia and HIV Infection

PURPOSE OF THE REVIEW

In our innate immune system, neutrophils are the first cells to sense signals of infection and to proceed to kill the invading pathogen. This is mediated by their production of neutrophil extracellular traps (NETS) to entrap pathogenic micro-organisms, preventing their amplification and dissemination. Pre-eclampsia (PE) is the leading cause of global maternal mortality, yet to date, there is no cure nor a gold-standard diagnostic strategy. The purpose of this review is to discover the role of neutrophils in PE as early identification markers. Additionally, this review aims to explore the role of neutrophils in HIV-infected pregnancies with PE as a source of synergy.

RECENT FINDINGS

Recent findings demonstrate an elevation of neutrophils and neutrophil extracellular traps (NETs) in PE placentae. This is due to their activation by excessive release of syncytiotrophoblast microparticles (STBM). There is also an elevation of NETs in HIV-infected placentae-where histone H3 entraps HIV by binding to its glycoprotein envelope. Additionally, histones H1 and H2A inhibit HIV infection. It is interesting to note that women with both PE and HIV infection have supressed NETs. This review focuses on the role of neutrophils in the synergy of PE and HIV infection. It is plausible that the deregulation of NETs in the synergy of pre-eclamptic HIV-infected women is strategic for the entrapment of the HIV-1 virus. Finally, it is plausible that neutrophils and NETS may act as early biomarkers of PE development. Graphical abstract.

Pathophysiology of the Venous Thromboembolism Risk in Preeclampsia

Preeclampsia complicates up to 8% of pregnancies and is a leading cause of fetomaternal morbidity andmortality. Treatment options are limited, with supportive care and delivery of the placenta representing the cornerstone of current management strategies. Derangements in blood coagulation are wellrecognised in this disorder and appear to favour an increased risk of venous thromboembolism among affected women. This risk appears to be most significant in the postpartum period. The mechanisms underlying this increased thrombosis risk remain to be fully elucidated although increased expression of procoagulant factors, endothelial dysfunction, attenuation of endogenous anticoagulant activity and increased platelet activity have been implicated in the prothrombotic tendency. Preeclampsia is also occasionally complicated by life-threatening haemorrhagic events and current evidence suggests that in some severe manifestations of this disease a coagulopathy with a clinical bleeding tendency may be the predominant haemostatic abnormality. Identifying affected women at significant risk of thrombosis and managing the competing thrombotic and haemorrhagic risks continue to be a significant clinical challenge. Derangements in blood coagulation are also implicated in the pathogenesis of preeclampsia; however, the role of antiplatelet or anticoagulant drugs in the prevention and treatment of this disorder remains a source of considerable debate. In addition, the potential role of specific haemostatic markers as diagnostic or screening tools for preeclampsia has also yet to be determined. Further characterisation of the underlying molecular mechanisms would likely be of major translational relevance and could provide insights into the pathogenesis of this disease as well as the associated haemostatic dysfunction.

Monocyte clearance of apoptotic neutrophils is unhindered in the presence of NETosis, but proteins of NET trigger ETosis in monocytes

Resolution of inflammation needs effective and timely removal of dead cells and other toxic products of neutrophils, monocytes, and macrophages. In this study, we evaluated the role of monocytes in the clearance of neutrophil extracellular trap (NET) and apoptotic neutrophils in the inflammation site. For this, monocytes were observed microscopically after exposing them with NETs and/or apoptotic bodies. A subset of monocytes exposed to NETs ejected extracellular traps and this was shown to be mediated by proteins like elastase and citrullinated histones present in NET supernatant. Monocytes showed a preference for the internalisation of the apoptotic body when both NET and apoptotic bodies were present in the medium. The study provides new insight into the role of monocytes in the clearance of NET and apoptotic neutrophils and this information may open up a way in formulating therapeutic strategies for accelerating resolution of inflammation.