Placental-specific sFLT-1: role in pre-eclamptic pathophysiology and its translational possibilities for clinical prediction and diagnosis

Gene therapy in preeclampsia: the dawn of a new era

Preeclampsia is a severe complication of pregnancy, affecting an estimated 4 million women annually. It is one of the leading causes of maternal and fetal mortality worldwide, and it has life-long consequences. The maternal multisystemic symptoms are driven by poor placentation, which causes syncytiotrophoblastic stress and the release of factors into the maternal bloodstream. Amongst them, the soluble fms-like tyrosine kinase-1 (sFLT-1) triggers extensive endothelial dysfunction by acting as a decoy receptor for the vascular endothelial growth factor (VEGF) and the placental growth factor (PGF). Current interventions aim to mitigate hypertension and seizures, but the only definite treatment remains induced delivery. Thus, there is a pressing need for novel therapies to remedy this situation. Notably, CBP-4888, a siRNA drug delivered subcutaneously to knock down sFLT1 expression in the placenta, has recently obtained Fast Track approval from the Food and Drug Administration (FDA) and is undergoing a phase 1 clinical trial. Such advance highlights a growing interest and significant potential in gene therapy to manage preeclampsia. This review summarizes the advances and prospects of gene therapy in treating placental dysfunction and illustrates crucial challenges and considerations for these emerging treatments.

A Single Trophoblast Layer Acts as the Gatekeeper at the Endothelial-Hematopoietic Crossroad in the Placenta

During embryonic development the placental vasculature acts as a major hematopoietic niche, where endothelial to hematopoietic transition ensures emergence of hematopoietic stem cells (HSCs). However, the molecular mechanisms that regulate the placental hematoendothelial niche are poorly understood. Using a parietal trophoblast giant cell (TGC)-specific knockout mouse model and single-cell RNA-sequencing, we show that the paracrine factors secreted by the TGCs are critical in the development of this niche. Disruptions in the TGC-specific paracrine signaling leads to the loss of HSC population and the concomitant expansion of a KDR+/DLL4+/PROM1+ hematoendothelial cell-population in the placenta. Combining single- cell transcriptomics and receptor-ligand pair analyses, we also define the parietal TGC- dependent paracrine signaling network and identify Integrin signaling as a fundamental regulator of this process. Our study elucidates novel mechanisms by which non-autonomous signaling from the primary parietal TGCs maintain the delicate placental hematopoietic- angiogenic balance and ensures embryonic and extraembryonic development.

Statins Prevent the Deleterious Consequences of Placental Chemerin Upregulation in Preeclampsia

BACKGROUND

Chemerin, an inflammatory adipokine, is upregulated in preeclampsia, and its placental overexpression results in preeclampsia-like symptoms in mice. Statins may lower chemerin.

METHODS

Chemerin was determined in a prospective cohort study in women suspected of preeclampsia and evaluated as a predictor versus the sFlt-1 (soluble fms-like tyrosine kinase-1)/PlGF (placental growth factor) ratio. Chemerin release was studied in perfused placentas and placental explants with or without the statins pravastatin and fluvastatin. We also addressed statin placental passage and the effects of chemerin in chorionic plate arteries.

RESULTS

Serum chemerin was elevated in women with preeclampsia, and its addition to a predictive model yielded significant effects on top of the sFlt-1/PlGF ratio to predict preeclampsia and its fetal complications. Perfused placentas and explants of preeclamptic women released more chemerin and sFlt-1 and less PlGF than those of healthy pregnant women. Statins reversed this. Both statins entered the fetal compartment, and the fetal/maternal concentration ratio of pravastatin was twice that of fluvastatin. Chemerin constricted plate arteries, and this was blocked by a chemerin receptor antagonist and pravastatin. Chemerin did not potentiate endothelin-1 in chorionic plate arteries. In explants, statins upregulated low-density lipoprotein receptor expression, which relies on the same transcription factor as chemerin, and NO release.

CONCLUSIONS

Chemerin is a biomarker for preeclampsia, and statins both prevent its placental upregulation and effects, in an NO and low-density lipoprotein receptor-dependent manner. Combined with their capacity to improve the sFlt-1/PlGF ratio, this offers an attractive mechanism by which statins may prevent or treat preeclampsia.

Advances in understanding canine pregnancy: Endocrine and morpho-functional regulation

Canine pregnancy relies on luteal steroidogenesis for progesterone (P4) production. The canine placenta responds to P4, depending on the nuclear P4 receptor (PGR). This has sparked interest in investigating the interaction between ovarian luteal steroids and the placenta in dogs. Canine placentation is characterized by restricted (shallow) trophoblast invasion, making the dog an interesting model for studying decidua-derived modulation of trophoblast invasion, compared with the more invasive (hemochorial) placentation. The PGR is expressed in maternally derived decidual cells and plays a crucial role in feto-maternal communication during pregnancy maintenance. Understanding PGR-mediated signalling has clinical implications for improving reproductive performance control in dogs. Altering the PGR signalling induces the release of PGF2α from the foetal trophoblast, hindering placental homeostasis, which can also be achieved with antigestagens like aglepristone. Consequently, luteolysis, both natural and antigestagen-induced, involves apoptosis, vascular lesion, and immune cell infiltration in the placenta, resulting in placentolysis and foetal membranes expulsion. Our laboratory developed the immortalized dog uterine stromal (DUS) cell line to study canine-specific decidualization. We study canine reproduction by observing physiological processes and investigating evidence-based mechanisms of decidualization and feto-maternal interaction. Our focus on morphology, function and molecular aspects enhances understanding and enables targeted and translational studies.

Longitudinal Associations between Ambient Air Pollution and Angiogenic Biomarkers among Pregnant Women in the LIFECODES Study, 2006-2008

BACKGROUND

Exposures to ambient air pollution during pregnancy have been linked to adverse pregnancy outcomes such as preeclampsia and fetal growth restriction. Although evidence has shown that women with preeclampsia have higher ratio of soluble fms-like tyrosine kinase 1 to placental growth factor (sFlt-1/PlGF ratio), the potential impact of air pollution on markers of placental growth and function has not been well studied.

OBJECTIVES

We aimed to examine longitudinal associations between ambient air pollution exposure and angiogenic factors among pregnant women in LIFECODES, a prospective birth cohort and biorepository in Massachusetts in the United States.

METHODS

PlGF and sFlt-1 were measured among pregnant women using plasma samples collected around 10, 18, 26, and 35 wk' gestation. Women's exposures to ozone (O 3 ), fine particulate matter with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ), and nitrogen dioxide (NO 2 ) within 1, 2, 4, and 8 wk prior to each plasma sample collection were estimated based on geocoded residential addresses, and mixed effect linear regression models were fitted to assess their associations with sFlt-1/PlGF ratio, sFlt-1 (ng/mL), and PlGF (pg/mL). Percent changes in outcomes associated with each interquartile range increase in exposures were reported, along with their 95% confidence intervals.

RESULTS

A total of 1,066 pregnant women were included. In the multipollutant models, significant associations were observed for increased sFlt-1/PlGF ratio (PM 2.5 3-8 wk' gestation, NO 2 : 35-39 wk' gestation), elevated sFlt-1 (O 3 : 26-34 wk' gestation, PM 2.5 : 3-8 wk' gestation), decreased sFlt-1 (NO 2 : 4-8 wk' gestation), and decreased PlGF (NO 2 : 34-39 wk' gestation) after adjusting for sociodemographic status, smoking, drinking, body mass index, parity, history of chronic hypertension, and conception time.

DISCUSSION

Exposures to PM 2.5 during early pregnancy and exposures to O 3 and NO 2 during late pregnancy were associated with increased sFlt-1/PlGF ratio, elevated sFlt-1 and with decreased PlGF, which may be a potential mechanism underlying ambient air pollution's impacts on adverse pregnancy and birth outcomes. https://doi.org/10.1289/EHP11909.

Calorie restriction and pravastatin administration during pregnancy in obese rhesus macaques modulates maternal and infant metabolism and infant brain and behavioral development

Background

Maternal obesity has been associated with a higher risk of pregnancy-related complications in mothers and offspring; however, effective interventions have not yet been developed. We tested two interventions, calorie restriction and pravastatin administration, during pregnancy in a rhesus macaque model with the hypothesis that these interventions would normalize metabolic dysregulation in pregnant mothers leading to an improvement in infant metabolic and cognitive/social development.

Methods

A total of 19 obese mothers were assigned to either one of the two intervention groups (n = 5 for calorie restriction; n = 7 for pravastatin) or an obese control group (n = 7) with no intervention, and maternal gestational samples and postnatal infant samples were compared with lean control mothers (n = 6) using metabolomics methods.

Results

Gestational calorie restriction normalized one-carbon metabolism dysregulation in obese mothers, but altered energy metabolism in her offspring. Although administration of pravastatin during pregnancy tended to normalize blood cholesterol in the mothers, it potentially impacted the gut microbiome and kidney function of their offspring. In the offspring, both calorie restriction and pravastatin administration during pregnancy tended to normalize the activity of AMPK in the brain at 6 months, and while results of the Visual Paired-Comparison test, which measures infant recognition memory, was not significantly impacted by either of the interventions, gestational pravastatin administration, but not calorie restriction, tended to normalize anxiety assessed by the Human Intruder test.

Conclusions

Although the two interventions tested in a non-human primate model led to some improvements in metabolism and/or infant brain development, negative impacts were also found in both mothers and infants. Our study emphasizes the importance of assessing gestational interventions for maternal obesity on both maternal and offspring long-term outcomes.

Molecular subclasses of preeclampsia characterized by a longitudinal maternal proteomics study: distinct biomarkers, disease pathways and options for prevention

OBJECTIVES

The heterogeneous nature of preeclampsia is a major obstacle to early screening and prevention, and a molecular taxonomy of disease is needed. We have previously identified four subclasses of preeclampsia based on first-trimester plasma proteomic profiles. Herein, we expanded this approach by using a more comprehensive panel of proteins profiled in longitudinal samples.

METHODS

Proteomic data collected longitudinally from plasma samples of women who developed preeclampsia (n=109) and of controls (n=90) were available from our previous report on 1,125 proteins. Consensus clustering was performed to identify subgroups of patients with preeclampsia based on data from five gestational-age intervals by using select interval-specific features. Demographic, clinical, and proteomic differences among clusters were determined. Differentially abundant proteins were used to identify cluster-specific perturbed KEGG pathways.

RESULTS

Four molecular clusters with different clinical phenotypes were discovered by longitudinal proteomic profiling. Cluster 1 involves metabolic and prothrombotic changes with high rates of early-onset preeclampsia and small-for-gestational-age neonates; Cluster 2 includes maternal anti-fetal rejection mechanisms and recurrent preeclampsia cases; Cluster 3 is associated with extracellular matrix regulation and comprises cases of mostly mild, late-onset preeclampsia; and Cluster 4 is characterized by angiogenic imbalance and a high prevalence of early-onset disease.

CONCLUSIONS

This study is an independent validation and further refining of molecular subclasses of preeclampsia identified by a different proteomic platform and study population. The results lay the groundwork for novel diagnostic and personalized tools of prevention.

Transcriptomic profiling of canine decidualization and effects of antigestagens on decidualized dog uterine stromal cells

Maternal-stroma derived decidual cells, the only cell population in the canine placenta expressing the nuclear progesterone (P4) receptor (PGR), are crucial for the maintenance of canine pregnancy. Decreased circulating progesterone (P4) levels, or blockage of PGR function with antigestagens, terminate canine pregnancy. As an in vitro model for canine decidualization, dog uterine stromal (DUS) cells can be decidualized in vitro with cAMP. The antigestagens aglepristone and mifepristone ablate the expression of decidualization markers in DUS cells (e.g., PGR, PRLR, IGF1 or PTGES). Here, the transcriptome profile of DUS cells was investigated to acquire deeper insights into decidualization-associated changes. Additionally, effects mediated by antigestagens (competitive PGR blockers) in decidualized cells were assessed. Decidualization led to the upregulation of 1841 differentially expressed genes (DEGs, P and FDR < 0.01) involved in cellular proliferation and adhesion, mesenchymal-epithelial transition, extracellular matrix organization, and vaso- and immunomodulation. The 1475 DEGs downregulated after decidualization were mostly associated with apoptosis and cell migration. In decidualized DUS cells, aglepristone modulated 1400 DEGs and mifepristone 1558 DEGs. Interestingly, around half of the identified DEGs were modulated by only one of the antigestagens. In all cases, however, PGR-blockage was mainly associated with an inversion of several decidualization-induced effects. Comparison between antigestagen-mediated effects and transcriptional changes in the canine placenta at term allowed the identification of 191 DEGs associated with diminished cell proliferation and adhesion, and vascular and immune modulation. This study emphasizes the importance of P4/PGR signaling for decidual cell function, providing new insights into the maintenance of canine pregnancy.

Placental Transcription Profiling in 6-23 Weeks' Gestation Reveals Differential Transcript Usage in Early Development

The human placenta is a rapidly developing transient organ that is key to pregnancy success. Early development of the conceptus occurs in a low oxygen environment before oxygenated maternal blood begins to flow into the placenta at ~10-12 weeks' gestation. This process is likely to substantially affect overall placental gene expression. Transcript variability underlying gene expression has yet to be profiled. In this study, accurate transcript expression profiles were identified for 84 human placental chorionic villus tissue samples collected across 6-23 weeks' gestation. Differential gene expression (DGE), differential transcript expression (DTE) and differential transcript usage (DTU) between 6-10 weeks' and 11-23 weeks' gestation groups were assessed. In total, 229 genes had significant DTE yet no significant DGE. Integration of DGE and DTE analyses found that differential expression patterns of individual transcripts were commonly masked upon aggregation to the gene-level. Of the 611 genes that exhibited DTU, 534 had no significant DGE or DTE. The four most significant DTU genes ADAM10, VMP1, GPR126, and ASAH1, were associated with hypoxia-responsive pathways. Transcript usage is a likely regulatory mechanism in early placentation. Identification of functional roles will facilitate new insight in understanding the origins of pregnancy complications.

The Role of Inorganics in Preeclampsia Assessed by Multiscale Multimodal Characterization of Placentae

Preeclampsia is one of the most dangerous diseases in pregnancy. Because of the hypertensive nature of preeclampsia, placental calcifications are believed to be a predictor for its occurrence, analogous to their role in cardiovascular diseases. However, the prevalence and the relevance of calcifications for the clinical outcome with respect to preeclampsia remains controversial. In addition, the role of other inorganic components present in the placental tissue in the development of preeclampsia has rarely been investigated. In this work, we therefore characterized inorganic constituents in placental tissue in groups of both normotensive and preeclamptic patients (N = 20 each) using a multi-scale and multi-modal approach. Examinations included elemental analysis (metallomics), sonography, computed tomography (CT), histology, scanning electron microscopy, X-ray fluorescence and energy dispersive X-ray spectroscopy. Our data show that tissue contents of several heavy metals (Al, Cd, Ni, Co, Mn, Pb, and As) were elevated whereas the Rb content was decreased in preeclamptic compared to normotensive placentae. However, the median mineral content (Ca, P, Mg, Na, K) was remarkably comparable between the two groups and CT showed lower calcified volumes and fewer crystalline deposits in preeclamptic placentae. Electron microscopy investigations revealed four distinct types of calcifications, all predominantly composed of calcium, phosphorus and oxygen with variable contents of magnesium in tissues of both maternal and fetal origin in both preeclamptic and normotensive placentae. In conclusion our study suggests that heavy metals, combined with other factors, can be associated with the development of preeclampsia, however, with no obvious correlation between calcifications and preeclampsia.

Hematobiochemical variability and predictors of new-onset and persistent postpartum preeclampsia

Preeclampsia (PE) can occur antepartum or postpartum. When it develops de novo after childbirth, it is termed new-onset postpartum PE (NOPPE). Often, antepartum PE disappears after childbirth; however, in some women it persists after childbirth. This form of PE is termed persistent PE (PPE). Thus, there are two forms of postpartum PE: NOPPE and PPE. The pathogenesis and pathophysiology of these diseases have not been fully characterized, and whether NOPPE and PPE are different or similar pathological conditions remains unexplored. Thus, we aimed to compare the haematological and biochemical characteristics of NOPPE and PPE, predict the occurrence of new-onset PE and identify lifestyles that predispose women to postpartum PE. A total of 130 women comprising 65 normotensive postpartum women, 33 NOPPE and 32 PPE women were recruited for this hospital-based case-control study. The socio-demographic and lifestyle characteristics of the participants were obtained through well-structured questionnaires. Haematological and biochemical indices were measured using automated analysers and ELISA. The prevalence of postpartum PE was 11.9%. Dyslipidaemia (p =  < 0.0001), hypomagnesaemia (p =  < 0.001), elevated serum levels of ALT, AST (p =  < 0.0001), sVCAM-1 (p =  < 0.0001) and sFlt-1 (p =  < 0.0001) were more prevalent and severe in the PPE than in the NOPPE. Sedentary lifestyle was common among both groups of hypertensive women. Elevated ALT and AST were significant predictors of NOPPE. These findings indicate that preeclampsia exists after childbirth in a high percentage of women. NOPPE and PPE are different pathological conditions that require different clinical management. Combined glucose, lipid and liver assessment could be useful in predicting postpartum PE.

How Soluble Fms-Like Tyrosine Kinase 1 Could Contribute to Blood-Brain Barrier Dysfunction in Preeclampsia?

Preeclampsia is a pregnancy-related syndrome that courses with severe cerebrovascular complications if not properly managed. Findings from pre-clinical and clinical studies have proposed that the imbalance between pro- and anti-angiogenic factors exhibited in preeclampsia is a major component of its pathophysiology. In this regard, measurement of circulating levels of soluble tyrosine kinase-1 similar to fms (sFlt-1), a decoy receptor for vascular endothelial growth factor (VEGF), is a moderately reliable biomarker for the diagnosis of preeclampsia. However, few studies have established a mechanistic approach to determine how the high levels of sFlt-1 are responsible for the endothelial dysfunction, and even less is known about its effects at the blood-brain barrier (BBB). Since the expression pattern of VEGF receptors type 1 and 2 in brain endothelial cells differs from the observed in peripheral endothelial cells, and components of the neurovascular unit of the BBB provide paracrine secretion of VEGF, this compartmentalization of VEGF signaling could help to see in a different viewpoint the role of sFlt-1 in the development of endothelial dysfunction. In this article, we provide a hypothesis of how sFlt-1 could eventually be a protective factor for brain endothelial cells of the BBB under preeclampsia.

Medawar's PostEra: Galectins Emerged as Key Players During Fetal-Maternal Glycoimmune Adaptation

Lectin-glycan interactions, in particular those mediated by the galectin family, regulate many processes required for a successful pregnancy. Over the past decades, increasing evidence gathered from in vitro and in vivo experiments indicate that members of the galectin family specifically bind to both intracellular and membrane bound carbohydrate ligands regulating angiogenesis, immune-cell adaptations required to tolerate the fetal semi-allograft and mammalian embryogenesis. Therefore, galectins play important roles in fetal development and placentation contributing to maternal and fetal health. This review discusses the expression and role of galectins during the course of pregnancy, with an emphasis on maternal immune adaptions and galectin-glycan interactions uncovered in the recent years. In addition, we summarize the galectin fingerprints associated with pathological gestation with particular focus on preeclampsia.

COVID-19, Pre-Eclampsia, and Complement System

COVID-19 is characterized by virus-induced injury leading to multi-organ failure, together with inflammatory reaction, endothelial cell (EC) injury, and prothrombotic coagulopathy with thrombotic events. Complement system (C) via its cross-talk with the contact and coagulation systems contributes significantly to the severity and pathological consequences due to SARS-CoV-2 infection. These immunopathological mechanisms overlap in COVID-19 and pre-eclampsia (PE). Thus, mothers contracting SARS-CoV-2 infection during pregnancy are more vulnerable to developing PE. SARS-CoV-2 infection of ECs, via its receptor ACE2 and co-receptor TMPRSS2, can provoke endothelial dysfunction and disruption of vascular integrity, causing hyperinflammation and hypercoagulability. This is aggravated by bradykinin increase due to inhibition of ACE2 activity by the virus. C is important for the progression of normal pregnancy, and its dysregulation can impact in the form of PE-like syndrome as a consequence of SARS-CoV-2 infection. Thus, there is also an overlap between treatment regimens of COVID-19 and PE. C inhibitors, especially those targeting C3 or MASP-2, are exciting options for treating COVID-19 and consequent PE. In this review, we examine the role of C, contact and coagulation systems as well as endothelial hyperactivation with respect to SARS-CoV-2 infection during pregnancy and likely development of PE.

Chemerin promotes the pathogenesis of preeclampsia by activating CMKLR1/p-Akt/CEBPɑ axis and inducing M1 macrophage polarization

A higher ratio of M1/M2 macrophages and an elevated chemerin level are both related to increased risk of preeclampsia. However, the crosstalk between these two events and their collective contribution to preeclampsia are not well understood. In this study, we assessed the impacts of chemerin chemokine-like receptor 1 (CMKLR1)/p-Akt/CEBPα axis in regulating macrophage polarization and mediating the pathogenic effects of chemerin on preeclampsia. We showed that chemerin, in a dose- and time-dependent manner, stimulated M1 macrophage polarization, inhibited macrophage-induced trophoblast invasion and migration, and suppressed macrophage-mediated angiogenesis. All these chemerin-induced phenotypes are essentially mediated by sequentially CMKLR1, Akt activation, and CEBPα. Mechanistically, CEBPα acted as a transcriptional activator for both IRF8 and chemerin. In vivo, chemerin aggravated preeclampsia, while α-NETA, an inhibitor for CMKLR1, significantly suppressed M1 macrophage polarization and alleviated preeclampsia. In summary, chemerin, by activating CMKLR1/Akt/CEBPα axis, forms a positive feedback loop, promotes M1 macrophage polarization, suppresses trophoblast migration/invasion and angiogenesis, and contributes to preeclampsia. Therefore, targeting chemerin signaling may benefit the prevention and/or treatment of preeclampsia.

Circulating levels of angiogenic factors and their association with preeclampsia among pregnant women at Mulago National Referral Hospital in Uganda

Preeclampsia (PE) is a major cause of maternal and new-born morbidity and mortality. Angiogenic factors contribute a major role in the vascular dysfunction associated with PE. We investigated the circulating levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF) and soluble Feline McDonough Sarcoma (fms)-like tyrosine kinase-1 (sFlt1), their association with PE and diagnostic performance of disease among pregnant women in Uganda. Using a case-control study design, 106 women with PE and 106 with normal pregnancy were enrolled. Demographic and clinical characteristics, and anticoagulated blood samples were collected from participants. Plasma VEGF, PlGF and sFlt1 levels were measured using Luminex and enzyme linked immunosorbent assays (ELISA). Conditional logistic regression was used to explore association of angiogenic factors with PE and receiver operating characteristic analysis was performed to investigate PE diagnostic performance. Levels of VEGF and PIGF were significantly lower in cases compared to controls (VEGF: median = 0.71 pg/ml (IQR = 0.38-1.11) Vs 1.20 pg/ml (0.64-1.91), p-value<0.001 and PlGF: 2.20 pg/ml (1.08-5.86) Vs 84.62 pg/ml (34.00-154.45), p-value<0.001). Plasma levels of sFlt1 were significantly higher in cases than controls (median = 141.13 (71.76-227.10) x103 pg/ml Vs 19.86 (14.20-29.37) x103 pg/ml). Increasing sFlt1 levels were associated with increased likelihood of PE (aOR = 4.73; 95% CI, 1.18-19.01; p-value = 0.0287). The sFlt1/PlGF ratio and sFlt1 had a better performance for diagnosis of PE, with AUC = 0.95 (95% CI, 0.93-0.98) followed by PlGF with AUC = 0.94 (95% CI, 0.91-0.97). Therefore, sFlt1, sFlt1/PlGF ratio and PlGF are potential candidates for incorporation into algorithms for PE diagnosis in the Ugandan population.

MicroRNA Profiles of Maternal and Neonatal Endothelial Progenitor Cells in Preeclampsia

Preeclampsia is associated with an increased cardiovascular morbidity of mother and offspring, thus contributing to a substantial burden in women and children’s health. It has been proven that endothelial progenitor cell (EPC) numbers and functional characteristics are impaired in cardiovascular disease and preeclampsia, although causative factors for the latter have remained elusive. MicroRNA (miRNA) modifications are a potential mechanism through which exposure to an altered environment translates into the development of chronic disease. In this study, we examined whether development of preeclampsia corresponds to alterations of miRNAs in maternal- and cord-blood-derived EPC. To test this end, we analyzed maternal and neonatal miRNAs via RNA sequencing from endothelial cells of preeclamptic and healthy controls in different cell culture passages. We were able to demonstrate differentially represented miRNAs in all groups. Hsa-miR-1270 showed significantly different levels in cord blood EPC from preeclampsia versus control and was negatively correlated with mRNA levels of its predicted targets ANGPTL7 and TFRC. Transfection with an hsa-miR-1270 inhibitor decreased the tube formation capacity and chemotactic motility but did not change proliferation in vitro. Target predictions and gene set enrichment analyses identified alternative splicing as a significantly enriched pathway for hsa-miR-1270. The top miRNAs in three other groups were predicted to target transcriptional and developmental pathways. Here, we showed for the first time significantly different levels of miRNAs and differently represented mRNA levels of predicted target genes in EPC derived from preeclampsia. Understanding the effects of preeclampsia on the epigenetic mechanisms of EPC will be crucial and may provide initial insights for further evaluation of the benefits of therapies targeting this cell population.

Unravelling the potential of angiogenic factors for the early prediction of preeclampsia

Preeclampsia is a multisystem, multiorgan hypertensive disorder of pregnancy responsible for maternal and perinatal morbidity and mortality in low- and middle-income countries. The classic diagnostic features hold less specificity for preeclampsia and its associated adverse outcomes, suggesting a need for specific and reliable biomarkers for the early prediction of preeclampsia. The imbalance of pro- and antiangiogenic circulatory factors contributes to the pathophysiology of preeclampsia. Several studies have examined the profile of angiogenic factors in preeclampsia to search for a biomarker that will improve the diagnostic ability of preeclampsia and associated adverse outcomes. This may help in more efficient patient management and the reduction of associated health care costs. This article reviews the findings from previous studies published to date on angiogenic factors and suggests a need to apply a multivariable model from the beginning of pregnancy and continuing throughout gestation for the early and specific prediction of preeclampsia.

Placental and maternal sFlt1/PlGF expression in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) and preeclampsia (PE) are both characterized by endothelial dysfunction and GDM women have higher incidence of PE. The placenta plays a key role in PE pathogenesis but its contribution to PE during GDM remains unclear. Herein, we compared placental and maternal blood anti-angiogenic soluble fms-like tyrosine kinase-1 (sFlt1) and pro-angiogenic Placental Growth Factor (PlGF) expressions in GDM and GDM-PE pregnancies compared to controls (CTRL) and PE cases. Electrochemiluminescence immunoassays showed a significantly higher maternal blood sFlt1/PlGF values in GDM-PE relative to CTRL and GDM pregnancies. We reported that placental PlGF gene expression was significantly decreased in GDM, PE and GDM-PE relative to CTRL. However, PlGF protein levels were significantly increased in GDM and GDM-PE relative to CTRL and PE placentae. Finally, sFlt1 gene expression was significantly increased in PE relative to CTRL, GDM and GDM-PE placentae. In contrast, sFlt1 protein expression was significantly decreased in GDM-PE relative to CTRL, GDM and PE placentae. Finally, higher sFlt1/PlGF ratio in GDM-PE maternal blood suggest that sFlt1 overproduction is related to PE onset also in GDM pregnancies even though characterized by a less severe endothelial dysfunction in terms of angiogenic biomarkers.

Mortality and neurological outcomes in extremely and very preterm infants born to mothers with hypertensive disorders of pregnancy

To evaluate the impact of maternal hypertensive disorders of pregnancy (HDP) on mortality and neurological outcomes in extremely and very preterm infants using a nationwide neonatal database in Japan. This population-based retrospective study was based on an analysis of data collected by the Neonatal Research Network of Japan from 2003 to 2015 of neonates weighing 1,500 g or less at birth, between 22 and 31 weeks’ gestation. A total of 21,659 infants were randomly divided into two groups, HDP (n = 4,584) and non-HDP (n = 4,584), at a ratio of 1:1 after stratification by four factors including maternal age, parity, weeks of gestation, and year of delivery. Short-term (neonatal period) and medium-term (3 years of age) mortality and neurological outcomes were compared between the two groups by logistic regression analyses. In univariate analysis, HDP was associated with an increased risk for in-hospital death (crude odds ratio [OR], 1.31; 95% confidence interval, 1.04–1.63) and a decreased risk for severe intraventricular haemorrhage (0.68; 0.53–0.87) and periventricular leukomalacia (0.60; 0.48–0.77). In multivariate analysis, HDP was significantly associated with a lower risk for in-hospital death (adjusted OR, 0.61; 0.47–0.80), severe intraventricular haemorrhage (0.47; 0.35–0.63), periventricular leukomalacia (0.59; 0.45–0.78), neonatal seizures (0.40; 0.28–0.57) and cerebral palsy (0.70; 0.52–0.95) at 3 years after adjustment for covariates including birth weight. These results were consistent with those of additional analyses, which excluded cases with histological chorioamnionitis and which divided the infants into two subgroups (22–27 gestational weeks and 28–31 gestational weeks). Maternal HDP was associated with an increased risk for in-hospital death without adjusting for covariates, but it was also associated with a lower risk for mortality and adverse neurological outcomes in extremely and very preterm infants if all covariates except HDP were identical.

PlGF Immunological Impact during Pregnancy

During pregnancy, the mother’s immune system has to tolerate the persistence of paternal alloantigens without affecting the anti-infectious immune response. Consequently, several mechanisms aimed at preventing allograft rejection, occur during a pregnancy. In fact, the early stages of pregnancy are characterized by the correct balance between inflammation and immune tolerance, in which proinflammatory cytokines contribute to both the remodeling of tissues and to neo-angiogenesis, thus, favoring the correct embryo implantation. In addition to the creation of a microenvironment able to support both immunological privilege and angiogenesis, the trophoblast invades normal tissues by sharing the same behavior of invasive tumors. Next, the activation of an immunosuppressive phase, characterized by an increase in the number of regulatory T (Treg) cells prevents excessive inflammation and avoids fetal immuno-mediated rejection. When these changes do not occur or occur incompletely, early pregnancy failure follows. All these events are characterized by an increase in different growth factors and cytokines, among which one of the most important is the angiogenic growth factor, namely placental growth factor (PlGF). PlGF is initially isolated from the human placenta. It is upregulated during both pregnancy and inflammation. In this review, we summarize current knowledge on the immunomodulatory effects of PlGF during pregnancy, warranting that both innate and adaptive immune cells properly support the early events of implantation and placental development. Furthermore, we highlight how an alteration of the immune response, associated with PlGF imbalance, can induce a hypertensive state and lead to the pre-eclampsia (PE).

Nanoparticle-Mediated Simultaneous Downregulation of Placental Nrf2 and sFlt1 Improves Maternal and Fetal Outcomes in a Preeclampsia Mouse Model

Preeclampsia has impacted 3-5% pregnancies among the world and its complications lead to both maternal and fetal morbidity and mortality. However, management of preeclampsia is limited. Nanoparticles targeting chondroitin sulfate A (CSA) can deliver drugs to placenta. Inactivation of soluble fms-like tyrosine kinase (sFlt-1) and nuclear factor-erythroid 2-like 2 (Nrf2) has been proved to alleviate preeclampsia and improve maternal and fetal outcomes. Carboxyl-polyethylene glycol-poly (d,l-lactide) (COOH-PEG5K-PLA8K), cationic lipid DOTAP, and siNrf2 and sisFlt-1 were used to construct the nanoparticles and conjugating peptides targeting CSA was fabricated to it. The expression levels of proteins and RNAs were estimated by qRT-PCR and Western blot assays. ELISA assays were performed to evaluate levels of circulating sFlt-1. The nanoparticles containing siNrf2 and sisFlt-1 are targeted to the placenta trophoblasts and downregulated the expression levels of Nrf2 and sFlt-1 as well as their downstream genes in the placental cells of model mice. Treatment of nanoparticles induced the expression of angiogenic factors in placenta. Knocking down Nrf2 and sFlt-1 synchronously alleviated the preeclampsia and increased the maternal and fetal outcomes in preeclampsia model mice. Nanoparticle-mediated simultaneous downregulation of placental Nrf2 and sFlt1 improved maternal and fetal outcomes in a preeclampsia mouse model.

Bioenergetic effects of hydrogen sulfide suppress soluble Flt-1 and soluble endoglin in cystathionine gamma-lyase compromised endothelial cells

Endothelial dysfunction is a hallmark of preeclampsia, a life-threatening complication of pregnancy characterised by hypertension and elevated soluble Fms-Like Tyrosine Kinase-1 (sFlt-1). Dysregulation of hydrogen sulfide (H₂S) by inhibition of cystathionine γ-lyase (CSE) increases sFlt-1 and soluble endoglin (sEng) release. We explored whether compromise in CSE/H₂S pathway is linked to dysregulation of the mitochondrial bioenergetics and oxidative status. We investigated whether these effects were linked to CSE-induced sFlt-1 and sEng production in endothelial cells. Here, we demonstrate that CSE/H₂S pathway sustain endothelial mitochondrial bioenergetics and loss of CSE increases the production of mitochondrial-specific superoxide. As a compensatory effect, low CSE environment enhances the reliance on glycolysis. The mitochondrial-targeted H₂S donor, AP39, suppressed the antiangiogenic response and restored the mitochondrial bioenergetics in endothelial cells. AP39 revealed that upregulation of sFlt-1, but not sEng, is independent of the mitochondrial H₂S metabolising enzyme, SQR. These data provide new insights into the molecular mechanisms for antiangiogenic upregulation in a mitochondrial-driven environment. Targeting H₂S to the mitochondria may be of therapeutic benefit in the prevention of endothelial dysfunction associated with preeclampsia.

Esomeprazole and sulfasalazine in combination additively reduce sFlt-1 secretion and diminish endothelial dysfunction: potential for a combination treatment for preeclampsia

Development and repurposing of therapies that show promise in the prevention or treatment of preeclampsia would be a major advance for the obstetrics field. We recently identified esomeprazole and sulfasalazine as potential candidates for the treatment of preeclampsia. Both reduce placental and endothelial secretion of sFlt-1 and sENG and mitigate endothelial dysfunction in vitro. Here we assessed whether esomeprazole and sulfasalazine in combination would additively attenuate the elevated release of anti-angiogenic factors and markers of endothelial dysfunction, key characteristics of preeclampsia. Primary placental tissue and cells, and primary endothelial cells were treated with esomeprazole and sulfasalazine alone and in combination. We assessed secretion of sFlt-1 and sENG and performed in vitro assays of endothelial dysfunction. Combining esomeprazole and sulfasalazine in lower concentrations caused an additive reduction in sFlt-1 secretion in primary cytotrophoblasts, placental explants and endothelial cells. No additive reduction was observed in sENG secretion when esomeprazole and sulfasalazine were combined. Together, esomeprazole and sulfasalazine additively reduced TNF-α-induced VCAM and ET-1 mRNA expression, and monocyte adhesion to endothelial cells. In conclusion, combining esomeprazole and sulfasalazine additively reduced secretion of sFlt-1 and markers of endothelial dysfunction. Combined administration of esomeprazole and sulfasalazine may provide a more effective treatment or prevention for preeclampsia compared to either as single agents.

Pathogenesis of Preeclampsia and Therapeutic Approaches Targeting the Placenta

Preeclampsia (PE) is a serious pregnancy complication, affecting about 5–7% of pregnancies worldwide and is characterized by hypertension and damage to multiple maternal organs, primarily the liver and kidneys. PE usually begins after 20 weeks’ gestation and, if left untreated, can lead to serious complications and lifelong disabilities—even death—in both the mother and the infant. As delivery is the only cure for the disease, treatment is primarily focused on the management of blood pressure and other clinical symptoms. The pathogenesis of PE is still not clear. Abnormal spiral artery remodeling, placental ischemia and a resulting increase in the circulating levels of vascular endothelial growth factor receptor-1 (VEGFR-1), also called soluble fms-like tyrosine kinase-1 (sFlt-1), are believed to be among the primary pathologies associated with PE. sFlt-1 is produced mainly in the placenta during pregnancy and acts as a decoy receptor, binding to free VEGF (VEGF-A) and placental growth factor (PlGF), resulting in the decreased bioavailability of each to target cells. Despite the pathogenic effects of increased sFlt-1 on the maternal vasculature, recent studies from our laboratory and others have strongly indicated that the increase in sFlt-1 in PE may fulfill critical protective functions in preeclamptic pregnancies. Thus, further studies on the roles of sFlt-1 in normal and preeclamptic pregnancies are warranted for the development of therapeutic strategies targeting VEGF signaling for the treatment of PE. Another impediment to the treatment of PE is the lack of suitable methods for delivery of cargo to placental cells, as PE is believed to be of placental origin and most available therapies for PE adversely impact both the mother and the fetus. The present review discusses the pathogenesis of PE, the complex role of sFlt-1 in maternal disease and fetal protection, and the recently developed placenta-targeted drug delivery system for the potential treatment of PE with candidate therapeutic agents.

Identification of Key Genes and Long Noncoding RNA-Associated Competing Endogenous RNA (ceRNA) Networks in Early-Onset Preeclampsia

Background

Preeclampsia (PE) is a pregnancy-specific hypertension syndrome and is one of the leading causes of maternal and perinatal morbidity and mortality. Long noncoding RNAs (lncRNAs) have been reported to be abnormally expressed in many diseases, including preeclampsia. The present study is aimed at identifying the key genes and lncRNA-associated competing endogenous RNA (ceRNA) networks in early-onset preeclampsia (EOPE).

Methods

We investigated expression profiles of differentially expressed lncRNAs (DElncRNAs) and genes (DEGs) in placental tissues of EOPE and healthy controls with Human LncRNA Array v4. The potential functions of DEGs and DElncRNAs were predicted using the clusterProfiler package. The lncRNA-mRNA coexpression network was constructed via Pearson's correlation coefficient. The protein-protein interaction (PPI) network of DEGs was constructed, and the hub genes were obtained using the STRING database and Cytoscape. The ceRNA networks were constructed based on miRWalk and LncBase v2. qRT-PCR was performed to confirm the expression of lncRNA MIR193BHG, PROX1-AS1, and GATA3-AS1. ROC curves were performed to assess the clinical value of lncRNA MIR193BHG, PROX1-AS1, and GATA3-AS1 in the diagnosis of EOPE.

Results

We found 6 hub genes (SPP1, CCR2, KIT, ENG, ACKR1, and FLT1) altered in placental tissues of EOPE and constructed a ceRNA network, including 21 lncRNAs, 3 mRNAs, and 69 miRNAs. The expression of lncRNA MIR193BHG and GATA3-AS1 were elevated and showed good clinical values for diagnosing EOPE.

Conclusion

This study provides novel insights into the lncRNA-related ceRNA network in EOPE and identified two lncRNAs as potential prognostic biomarkers in EOPE.

Assisted reproductive technologies induce temporally specific placental defects and the preeclampsia risk marker sFLT1 in mouse

Although widely used, assisted reproductive technologies (ARTs) are associated with adverse perinatal outcomes. To elucidate their underlying causes, we have conducted a longitudinal analysis of placental development and fetal growth using a mouse model to investigate the effects of individual ART procedures: hormone stimulation, in vitro fertilization (IVF), embryo culture and embryo transfer. We demonstrate that transfer of blastocysts naturally conceived without hormone stimulation and developed in vivo prior to transfer can impair early placentation and fetal growth, but this effect normalizes by term. In contrast, embryos cultured in vitro before transfer do not exhibit this compensation but rather display placental overgrowth, reduced fetal weight, reduced placental DNA methylation and increased levels of sFLT1, an anti-angiogenic protein implicated in causing the maternal symptoms of preeclampsia in humans. Increases in sFLT1 observed in this study suggest that IVF procedures could increase the risk for preeclampsia. Moreover, our results indicate that embryo culture is the major factor contributing to most placental abnormalities and should therefore be targeted for optimization.

Changes in pregnancy-related serum biomarkers early in gestation are associated with later development of preeclampsia

Background

Placental protein expression plays a crucial role during pregnancy. We hypothesized that: (1) circulating levels of pregnancy-associated, placenta-related proteins throughout gestation reflect the temporal progression of the uncomplicated, full-term pregnancy, and can effectively estimate gestational ages (GAs); and (2) preeclampsia (PE) is associated with disruptions in these protein levels early in gestation; and can identify impending PE. We also compared gestational profiles of proteins in the human and mouse, using pregnant heme oxygenase-1 (HO-1) heterozygote (Het) mice, a mouse model reflecting PE-like symptoms.

Methods

Serum levels of placenta-related proteins–leptin (LEP), chorionic somatomammotropin hormone like 1 (CSHL1), elabela (ELA), activin A, soluble fms-like tyrosine kinase 1 (sFlt-1), and placental growth factor (PlGF)–were quantified by ELISA in blood serially collected throughout human pregnancies (20 normal subjects with 66 samples, and 20 subjects who developed PE with 61 samples). Multivariate analysis was performed to estimate the GA in normal pregnancy. Mean-squared errors of GA estimations were used to identify impending PE. The human protein profiles were then compared with those in the pregnant HO-1 Het mice.

Results

An elastic net-based gestational dating model was developed (R² = 0.76) and validated (R² = 0.61) using serum levels of the 6 proteins measured at various GAs from women with normal uncomplicated pregnancies. In women who developed PE, the model was not (R² = -0.17) associated with GA. Deviations from the model estimations were observed in women who developed PE (P = 0.01). The model developed with 5 proteins (ELA excluded) performed similarly from sera from normal human (R² = 0.68) and WT mouse (R² = 0.85) pregnancies. Disruptions of this model were observed in both human PE-associated (R² = 0.27) and mouse HO-1 Het (R² = 0.30) pregnancies. LEP outperformed sFlt-1 and PlGF in differentiating impending PE at early human and late mouse GAs.

Conclusions

Serum placenta-related protein profiles are temporally regulated throughout normal pregnancies and significantly disrupted in women who develop PE. LEP changes earlier than the well-established biomarkers (sFlt-1 and PlGF). There may be evidence of a causative action of HO-1 deficiency in LEP upregulation in a PE-like murine model.

Preeclampsia – Prediction and Monitoring Factors

Preeclampsia is one of the leading causes of maternal and perinatal morbidity and mortality, usually characterized by hypertension and proteinuria. Despite high incidence of preeclampsia the pathophysiological basis of preeclampsia is still not clear and there are a number of mechanisms and signaling pathways that intertwine. It is very important to develop specific and reliable predictive algorithms in order to enable early initiation of therapy due to facts that incidence of preeclampsia has upward trend and that cause adverse maternal and fetal outcome. Some of the most commonly used methods for prediction of preeclampsia include uterine artery Doppler velocimetry, determination of some microRNA, such as miR-210, and assessment of various pro-angiogenic and anti-angiogenic factors from blood. Angiogenic factors that possibly have most important role in pathogenesis of preeclampsia are vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), which promote angiogenesis, and soluble fms-like tyrosine kinase-1 (sFlt1) and soluble form of endoglin (s-Eng), which exhibit anti-angiogenic properties. Aggravating circumstance is that preeclampsia has heterogeneous origin, and due to this fact, the value of individual markers can vary significantly. There is a constant tendency for creating comprehensive algorithm for prediction of preeclampsia which would be sufficiently specific and sensitive, and in the same time cheap and available. In that sense, new clinical studies are needed to show the most effective combination of parameters in the predeclampsia prediction.

Abnormal expression and clinical significance of 25-hydroxyvitamin D and sFlt-1 in patients with preeclampsia

Objective

To determine the association between levels of serum 25-hydroxyvitamin D (25[OH]D) and soluble fms-like tyrosine kinase 1 (sFlt-1) in patients with preeclampsia.

Methods

Clinical and demographic data were collected from patients with preeclampsia and healthy pregnant controls. Serum 25(OH)D and sFlt-1 levels were evaluated by enzyme-linked immunosorbent assay and their correlations were determined using Spearman’s rank correlation coefficient. Associations between serum 25(OH)D and sFlt-1 levels and disease severity and clinical parameters were evaluated.

Results

Significantly lower serum 25(OH)D and higher sFlt-1 levels were observed in patients with preeclampsia (n = 100) versus controls (n = 100), and 25(OH)D was inversely correlated with sFlt-1 in patients with preeclampsia. Serum 25(OH)D levels were reduced, while sFlt-1 concentration was increased in patients with severe versus mild preeclampsia. Serum 25(OH)D levels were reduced in late-onset versus early-onset severe preeclampsia. Patients with preeclampsia who had lower serum 25(OH)D or elevated sFlt-1 levels showed significantly higher blood pressure indexes versus those with higher 25(OH)D or lower sFlt-1.

Conclusions

Low serum 25(OH)D and high sFlt-1 may be candidate biomarkers for preeclampsia diagnosis and prognosis.

Modulation of Receptor Tyrosine Kinase Activity through Alternative Splicing of Ligands and Receptors in the VEGF-A/VEGFR Axis

Vascular endothelial growth factor A (VEGF-A) signaling is essential for physiological and pathological angiogenesis. Alternative splicing of the VEGF-A pre-mRNA gives rise to a pro-angiogenic family of isoforms with a differing number of amino acids (VEGF-A_xxxa), as well as a family of isoforms with anti-angiogenic properties (VEGF-A_xxxb). The biological functions of VEGF-A proteins are mediated by a family of cognate protein tyrosine kinase receptors, known as the VEGF receptors (VEGFRs). VEGF-A binds to both VEGFR-1, largely suggested to function as a decoy receptor, and VEGFR-2, the predominant signaling receptor. Both VEGFR-1 and VEGFR-2 can also be alternatively spliced to generate soluble isoforms (sVEGFR-1/sVEGFR-2). The disruption of the splicing of just one of these genes can result in changes to the entire VEGF-A/VEGFR signaling axis, such as the increase in VEGF-A₁₆₅a relative to VEGF-A₁₆₅b resulting in increased VEGFR-2 signaling and aberrant angiogenesis in cancer. Research into this signaling axis has recently focused on manipulating the splicing of these genes as a potential therapeutic avenue in disease. Therefore, further research into understanding the mechanisms by which the splicing of VEGF-A/VEGFR-1/VEGFR-2 is regulated will help in the development of drugs aimed at manipulating splicing or inhibiting specific splice isoforms in a therapeutic manner.

The Immunogenetic Conundrum of Preeclampsia

Pregnancy is an immunological challenge to the mother. The fetal tissues including the placenta must be protected from activation of the maternal immune system. On the other hand, the placental tissue sheds into the maternal circulation and must be adequately identified and phagocytized by the maternal immune system. During a healthy pregnancy, numerous immunosuppressive processes take place that allow the allograft fetus to thrive under exposure to humoral and cellular components of the maternal immune system. Breakdown of immune tolerance may result in sterile inflammation and cause adverse pregnancy outcomes such as preeclampsia, a vascular disease of the pregnancy with unpredictable course and symptoms from several organs. Immunological incompatibility between mother and fetus is strongly indicated in preeclampsia. Recently, genetic factors linking immunological pathways to predisposition to preeclampsia have been identified. In this mini-review genetic variation in immunological factors are discussed in the context of preeclampsia. Specifically, we explore immunogenetic and immunomodulary mechanisms contributing to loss of tolerance, inflammation, and autoimmunity in preeclampsia.

Upregulation and release of soluble fms-like tyrosine kinase receptor 1 mediated by complement activation in human syncytiotrophoblast cells

PROBLEM

Antiangiogenic molecule soluble fms-like tyrosine kinase receptor 1 (sFLT1) released from trophoblast cells is associated with pregnancy-specific hypertensive disorder pre-eclampsia. Cause of elevated sFLT1 in pre-eclampsia patients is not well understood. Despite evidence of excess systemic and placental complement activation in pre-eclampsia patients, its role in pathophysiology is not clear. If the complement activation plays a role in upregulation and secretion of sFLT1 is not known.

METHOD OF STUDY

Human trophoblast cells were isolated from term placentas and allowed to syncytialize. Complement was activated in vitro at sublethal levels on syncytiotrophoblast cells. Effect of complement activation on expression and release of sFLT1 was assessed by comparing its levels in these cells with and without complement activation.

RESULTS

Sublethal level of complement activation on syncytialized human trophoblast cells induced upregulation of sFLT1 mRNA and protein. Complement also induced secretion of sFLT1 in a manner depending on degree of activation. Anaphylatoxins C3a induced upregulation but not the release of sFLT1. Release of terminal membrane attack complex (MAC) was associated with sFLT1 secretion.

CONCLUSION

Complement activation plays a major role in both the expression and secretion of sFLT1 from syncytial trophoblast cells. The terminal MAC complex is involved in its secretion. Increased levels of sFLT1 in pre-eclampsia patients may be due to complement-induced upregulation and secretion.

Positive and Negative Regulation of Angiogenesis by Soluble Vascular Endothelial Growth Factor Receptor-1

Vascular endothelial growth factor receptor (VEGFR)-1 exists in different forms, derived from alternative splicing of the same gene. In addition to the transmembrane form, endothelial cells produce a soluble VEGFR-1 (sVEGFR-1) isoform, whereas non-endothelial cells produce both sVEGFR-1 and a different soluble molecule, known as soluble fms-like tyrosine kinase (sFlt)1-14. By binding members of the vascular endothelial growth factor (VEGF) family, the soluble forms reduce the amounts of VEGFs available for the interaction with their transmembrane receptors, thereby negatively regulating VEGFR-mediated signaling. In agreement with this activity, high levels of circulating sVEGFR-1 or sFlt1-14 are associated with different pathological conditions involving vascular dysfunction. Moreover, sVEGFR-1 and sFlt1-14 have an additional role in angiogenesis: they are deposited in the endothelial cell and pericyte extracellular matrix, and interact with cell membrane components. Interaction of sVEGFR-1 with &alpha;5&beta;1 integrin on endothelial cell membranes regulates vessel growth, triggering a dynamic, pro-angiogenic phenotype. Interaction of sVEGFR-1/sFlt1-14 with cell membrane glycosphingolipids in lipid rafts controls kidney cell morphology and glomerular barrier functions. These cell⁻matrix contacts represent attractive novel targets for pharmacological intervention in addition to those addressing interactions between VEGFs and their receptors.

Causative Effects of Genetically Determined High Maternal/Fetal Endothelin-1 on Preeclampsia-Like Conditions in Mice

Endothelin-1 (ET-1) is implicated in the pathophysiology of preeclampsia. An association between an EDN1 gene polymorphism with high ET-1 and preeclampsia was reported in humans, but their cause and effect relationships have not been defined. We examined the pregnancy effects in mice with a modified Edn1 allele that increases mRNA stability and thus ET-1 production. Heterozygous Edn1^H/+ females showed no obvious abnormalities before pregnancy, but when mated with wild-type (WT) males developed a full spectrum of preeclampsia-like phenotypes, including increased systolic blood pressure, proteinuria, glomerular endotheliosis, and intrauterine fetal growth restriction. At 7.5 days post-coitus, the embryos from Edn1^H/+ dams, regardless of their Edn1 genotype, lagged 12 hours in development compared with embryos from WT dams, had disoriented ectoplacental cones, and retained high E-cadherin expression. In contrast, WT females mated with Edn1^H/+ males, which also carried half of the fetuses with Edn1^H/+ genotype, showed a mild systolic blood pressure increase only. These WT dams had 2× higher plasma soluble fms-like tyrosine kinase-1 than WT dams mated with WT males. In human first trimester trophoblast cells, pharmacological doses of ET-1 increased the cellular sFlt1 transcripts and protein secretion via both type A and B ET-1 receptors. Our data demonstrate that high maternal ET-1 production causes preeclampsia-like phenotypes during pregnancy, affecting both initial stage of trophoblast differentiation/invasion and maternal peripheral vasculature during late gestation. High fetal ET-1 production, however, could cause increased soluble fms-like tyrosine kinase-1 in the maternal circulation and contribute to blood pressure elevation.

Combining metformin and esomeprazole is additive in reducing sFlt-1 secretion and decreasing endothelial dysfunction - implications for treating preeclampsia

INTRODUCTION

The discovery of new treatments that prevent or treat preeclampsia would be a major advance. Antiangiogenic factors soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sENG) are secreted in excess from the placenta, causing hypertension, endothelial dysfunction, and multiorgan injury. We recently identified metformin and esomeprazole as potential treatments for preeclampsia. Both reduce placental and endothelial secretion of sFlt-1 and soluble endoglin, and reduce endothelial dysfunction.

OBJECTIVES

We set out to assess whether combining metformin and esomeprazole would additively reduce sFlt-1 and soluble endoglin secretion and reduce endothelial dysfunction (verses drug alone). Metformin and esomeprazole were added to primary placental cells and tissues, and endothelial cells and their effects on sFlt-1 and soluble endoglin secretion were assessed in vitro. Tumor necrosis factor-α (TNF-α) was added to endothelial cells to induce dysfunction in vitro. We examined the ability of metformin + esomeprazole to rescue TNF-α induced vascular cell adhesion molecule-1 (VCAM-1) and Endothelin-1 (ET-1) expression, leukocyte adhesion (markers of endothelial dysfunction).

RESULTS

Combining metformin and esomeprazole was additive at reducing sFlt-1 secretion and expression of sFlt-1 e15a mRNA isoform in primary cytotrophoblast, placental explants and endothelial cells. In contrast, no additive reduction in sENG was observed with combined metformin and esomeprazole. The low-dose combination of metformin + esomeprazole additively reduced TNF-α-induced VCAM-1 mRNA, but not VCAM-1 protein expression. There was no additive reduction when combining metformin and esomeprazole on TNF-α induced PBMC adhesion to endothelial cells. However, combining metformin and esomeprazole additively reduced ET-1 mRNA expression.

CONCLUSIONS

In conclusion combining metformin and esomeprazole additively reduced secretion of sFlt-1, and markers of endothelial dysfunction. The combination of metformin and esomeprazole may provide a more effective treatment or prevention for preeclampsia compared to either as single agents.

Maternal serum autotaxin levels in early- and late-onset preeclampsia

PURPOSE

We aimed to compare the serum autotaxin levels in early- and late- preeclamptic and healthy pregnant patients at a university hospital.

METHODS

A total of 55 singleton preeclamptic women who delivered at Cerrahpasa Medical Faculty were included in the study. The patients were subdivided into two groups: early-onset preeclampsia (n = 31) and late-onset preeclampsia (n = 24). Demographic and clinical data were compared between early-onset and late-onset preeclamptic patients. The control group was composed of 32 healthy pregnant patients.

RESULTS

The mean autotaxin levels were 1.16 ± 0.97 and 0.7 ± 0.35 ng/ml in the early- and late-onset preeclampsia groups, respectively. Autotaxin levels were significantly higher in early-onset preeclampsia group compared with late-onset preeclampsia group. Autotaxin levels were found to be significantly higher in preeclamptic patients compared with control group. Serum autotaxin levels showed a significant positive correlation with maternal systolic, diastolic blood pressures and uric acid levels.

CONCLUSION

Autotaxin might be a promising marker for detecting early-onset preeclampsia. However, further studies are necessary to confirm this hypothesis.