Preeclampsia: 2-methoxyestradiol induces cytotrophoblast invasion and vascular development specifically under hypoxic conditions

Effects of an aryl hydrocarbon receptor ligand on human trophoblast cell development

STUDY QUESTION

How does activation of aryl hydrocarbon receptor (AHR) signaling affect human trophoblast cell development and differentiation?

SUMMARY ANSWER

AHR activation alters gene expression without impairing the ability of trophoblast cells to maintain a stem cell state or differentiate into essential cell types, such as extravillous trophoblast (EVT) cells or syncytiotrophoblast (ST), while promoting the production of 2-methoxy estradiol (2ME), which may impact placental development.

WHAT IS KNOWN ALREADY

The placenta serves both as a nutrient delivery system and a protective barrier against environmental toxins. AHR signaling is known to mediate cellular responses to environmental pollutants, potentially affecting trophoblast cell function, but the specific impacts of AHR activation on these cells were not fully understood.

STUDY DESIGN, SIZE, DURATION

This study utilized an in vitro model of human trophoblast stem (TS) cells to investigate the downstream effects of AHR activation. The study focused on both undifferentiated TS cells and cells undergoing differentiation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human TS cells were used as a model system. Researchers examined the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure in TS cells maintained in their stem state and in TS cells induced to differentiate into EVT cells or ST. The study assessed changes in gene expression, particularly focusing on CYP1A1 and CYP1B1, as well as the production of 2ME.

MAIN RESULTS AND THE ROLE OF CHANCE

AHR activation stimulated the expression of CYP1A1 and CYP1B1, key genes associated with AHR signaling, in both undifferentiated and differentiating trophoblast cells. While AHR activation did not impact the ability of the cell to remain in a stem state or differentiate, it increased the production of 2ME, which may influence placentation. These effects were dependent on AHR signaling.

LARGE SCALE DATA

n/a.

LIMITATIONS, REASONS FOR CAUTION

This study was conducted in vitro, which may not fully replicate in vivo conditions. Further research is needed to confirm whether these findings apply to placental development in humans.

WIDER IMPLICATIONS OF THE FINDINGS

The results suggest that AHR signaling activated by environmental pollutants could have a significant impact on placental development through mechanisms involving AHR activation. These findings may have broader implications for understanding how environmental factors affect fetal development.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by the National Institutes of Health: ES028957, HD020676, ES029280, HD105734, HD112559, and the Sosland Foundation. The authors declare no conflicts of interest.

Aryl Hydrocarbon Receptor Activation Drives 2-Methoxy Estradiol Secretion in Human Trophoblast Stem Cell Development

STUDY QUESTION

How does activation of AHR signaling affect human trophoblast cell development and differentiation?

SUMMARY ANSWER

AHR activation leads to altered gene expression but does not hinder the ability of trophoblast cells to remain in a stem cell state or differentiate into essential cell types, such as extravillous trophoblast cells (EVT) or syncytiotrophoblast (ST). It also promotes the production of 2 methoxy estradiol (2ME), a compound that could influence placental development.

WHAT IS KNOWN ALREADY

The placenta serves both as a nutrient delivery system and a protective barrier against environmental toxins. AHR signaling is known to mediate cellular responses to environmental pollutants, potentially affecting trophoblast cell functions, but the specific impacts of AHR activation on these cells were not fully understood.

STUDY DESIGN SIZE DURATION

This study utilized an in vitro model of human trophoblast stem (TS) cells to investigate the downstream effects of AHR activation. The study focused on both undifferentiated TS cells and cells undergoing differentiation.

PARTICIPANTS/MATERIALS SETTING METHODS

Human trophoblast stem (TS) cells were used as the model system. Researchers examined the effects of TCDD exposure in both TS cells maintained in their stem state and those induced to differentiate into EVT or ST. The study assessed changes in gene expression, particularly focusing on CYP1A1 and CYP1B1, as well as the production of 2ME.

MAIN RESULTS AND THE ROLE OF CHANCE

AHR activation stimulated the expression of CYP1A1 and CYP1B1, key genes associated with AHR signaling, in both undifferentiated and differentiating trophoblast cells. While AHR activation did not impact the cells ability to remain in a stem state or differentiate, it increased the production of 2ME, which may influence placental function. These effects were dependent on AHR signaling.

LIMITATIONS REASONS FOR CAUTION

This study was conducted in vitro, which may not fully replicate human conditions. Further research is needed to confirm whether these findings apply to actual placental development in humans.

WIDER IMPLICATIONS OF THE FINDINGS

The results suggest that AHR signaling activated by environmental pollutants could have a subtle but significant impact on placental development through mechanisms involving AHR activation. These findings may have broader implications for understanding how environmental factors affect fetal development.

STUDY FUNDING/COMPETING INTERESTS

This work was funded by the National Institutes of Health: ES028957, HD020676, ES029280, HD105734 and the Sosland Foundation. The authors declare no conflicts of interest.

Pregnancy by Oocyte Donation: Reviewing Fetal-Maternal Risks and Complications

Oocyte donation (OD) has greatly improved over the last three decades, becoming a preferred practice of assisted reproductive technology (ART) for infertile women wishing for motherhood. Through OD, indeed, it has become possible to overcome the physiological limitation due to the ovarian reserve (OR) exhaustion as well as the poor gamete reliability which parallels the increasing age of women. However, despite the great scientific contribution related to the success of OD in the field of infertility, this practice seems to be associated with a higher rate of major risky events during pregnancy as recurrent miscarriage, infections and placental diseases including gestational hypertension, pre-eclampsia and post-partum hemorrhage, as well as several maternal-fetal complications due to gametes manipulation and immune system interaction. Here, we will revisit this questioned topic since a number of studies in the medical literature focus on the successful aspects of the OD procedure in terms of pregnancy rate without, however, neglecting the risks and complications potentially linked to external manipulation or heterologous implantation.

Regulator of G protein signaling 2 is inhibited by hypoxia-inducible factor-1α/E1A binding protein P300 complex upon hypoxia in human preeclampsia

BACKGROUND

Preeclampsia is a pregnancy-related complication that causes maternal and fetal mortality. Despite extensive studies showing the role of hypoxia in preeclampsia progression, the specific mechanism remains unclear. The purpose of this study was to explore the possible mechanism underlying hypoxia in preeclampsia.

METHODS

Human trophoblast-like JEG-3 cell line was used to investigate the molecular mechanisms underlying hypoxia contribution to preeclampsia and the expression correlation of key molecules was examined in human placental tissues. Methods include JEG-3 cell culture and hypoxia induction, RNA isolation and quantitative real-time PCR, transient transfection and dual-luciferase assay, western blot, immunoprecipitation, immunofluorescence staining, cell proliferation assay, chromatin immunoprecipitation assay, obtainment of human placental tissue sample and immunohistochemistry staining.

RESULTS

Hypoxia-Inducible Factor-1α is up-regulated in clinical preeclampsia samples, where Regulator of G Protein Signaling 2 is down-regulated. Mechanistically, Hypoxia-Inducible Factor-1α is induced in response to hypoxia, which up-regulates E1A binding protein P300 expression and thereby forms a Hypoxia-Inducible Factor-1α/E1A binding protein P300 protein-protein complex that binds to the promoter of gene Regulator of G Protein Signaling 2 and subsequently inhibits the transcription of Regulator of G Protein Signaling 2, possibly contributing to the preeclampsia development. In addition, the expression of E1A binding protein P300 is increased in preeclampsia samples, and the expression of Regulator of G Protein Signaling 2 in preeclamptic placentas inversely correlates with the levels of E1A binding protein P300.

CONCLUSION

Our findings may provide novel insights into understanding the molecular pathogenesis of preeclampsia and may be a prognostic biomarker and therapeutic target for preeclampsia.

Treatment with 2-methoxyestradiol increases endothelial nitric oxide synthase activity via scavenger receptor class BI in human umbilical vein endothelial cells

Concentrations of 2-methoxyestradiol (2ME2), a principal metabolite of estradiol, are significantly lower in women with severe preeclampsia. Nitric oxide (NO) released by endothelial nitric oxide synthase (eNOS) plays an important role in regulating cardiovascular homeostasis. Importantly, high-density lipoprotein (HDL) stimulates eNOS activity via endothelial human scavenger receptor class B type I (hSR-BI/CLA-1). Here, we aimed to determine the effect of 2ME2 on hSR-BI/CLA-1 expression in human umbilical vein endothelial cells (HUVECs). hSR-BI/CLA-1 expression was measured by real-time PCR, western blotting and reporter gene assays; eNOS activity was assessed by the measurement of eNOS phosphorylation. Both the mRNA and protein concentrations of hSR-BI/CLA-1 were significantly increased by 2ME2 in HUVECs. 2ME2 also dose-dependently increased the transcriptional activity of the hSR-BI/CLA-1 promoter. The effect of 2ME2 treatment on the promoter activity of hSR-BI/CLA-1 was abrogated by treatment with LY294002, a specific inhibitor of phosphatidylinositol 3-kinase, as was the increase in HDL-induced eNOS activation. Notably, constitutively active Akt increased the activity of the hSR-BI/CLA-1 promoter, whereas dominant-negative Akt abolished the effect of 2ME2 treatment on hSR-BI/CLA-1 promoter activity. The nuclear Sp1 protein concentration was significantly increased by exposure to 2ME2 and Sp1 overexpression increased the promoter activity of the hSR-BI/CLA gene. Furthermore, knockdown of Sp1 inhibited the effect of 2ME2 treatment on hSR-BI/CLA-1 protein expression. These results indicate that 2ME2 treatment increases HDL-dependent eNOS phosphorylation by upregulating endothelial hSR-BI/CLA-1 expression, suggesting that 2ME2 has a potential therapeutic value in the treatment of preeclampsia.

Secretory products of the corpus luteum and preeclampsia

BACKGROUND

Despite significant advances in our understanding of the pathophysiology of preeclampsia (PE), there are still many unknowns and controversies in the field. Women undergoing frozen-thawed embryo transfer (FET) to a hormonally prepared endometrium have been found to have an unexpected increased risk of PE compared to women who receive embryos in a natural FET cycle. The differences in risk have been hypothesized to be related to the absence or presence of a functioning corpus luteum (CL).

OBJECTIVE AND RATIONALE

To evaluate the literature on secretory products of the CL that could be essential for a healthy pregnancy and could reduce the risk of PE in the setting of FET.

SEARCH METHODS

For this review, pertinent studies were searched in PubMed/Medline (updated June 2020) using common keywords applied in the field of assisted reproductive technologies, CL physiology and preeclampsia. We also screened the complete list of references in recent publications in English (both animal and human studies) on the topics investigated. Given the design of this work as a narrative review, no formal criteria for study selection or appraisal were utilized.

OUTCOMES

The CL is a major source of multiple factors regulating reproduction. Progesterone, estradiol, relaxin and vasoactive and angiogenic substances produced by the CL have important roles in regulating its functional lifespan and are also secreted into the circulation to act remotely during early stages of pregnancy. Beyond the known actions of progesterone and estradiol on the uterus in early pregnancy, their metabolites have angiogenic properties that may optimize implantation and placentation. Serum levels of relaxin are almost undetectable in pregnant women without a CL, which precludes some maternal cardiovascular and renal adaptations to early pregnancy. We suggest that an imbalance in steroid hormones and their metabolites and polypeptides influencing early physiologic processes such as decidualization, implantation, angiogenesis and maternal haemodynamics could contribute to the increased PE risk among women undergoing programmed FET cycles.

WIDER IMPLICATIONS

A better understanding of the critical roles of the secretory products of the CL during early pregnancy holds the promise of improving the efficacy and safety of ART based on programmed FET cycles.

Nested Case-Control Study of Corin Combined with sFlt-1/PLGF in Predicting the Risk of Preeclampsia

Background

Preeclampsia (PE), a serious pregnancy disorder, is responsible for maternal and fetal mortality worldwide. At present, numerous candidate biomarkers have been studied to predict PE.

Objective

To explore the role of Corin in PE risk prediction and then evaluate the predictive ability of soluble vascular endothelial growth factor receptor-1 (sFlt-1), placenta growth factor (PLGF), and sFlt-1/PLGF after the addition of Corin.

Methods

A total of 135 pregnant women from Affiliated Hospital of Shandong University of Traditional Chinese Medicine participated in this study in their first trimester. A nested case–control study was conducted and all subjects were divided into PE groups (n=46) and controls (n=89). The levels of PLGF, sFlt-1, sFlt-1/PLGF ratio, and Corin of the two groups at 12–16 weeks of gestation were measured and analyzed. Receiver operating characteristic (ROC) curve, net reclassification index (NRI) and integrated discrimination index (IDI) were calculated to evaluate the predictive ability of various biomarkers.

Results

The concentrations of sFlt-1, sFlt-1/PLGF, and Corin in PE group were significantly higher than that in controls, while the concentration of PLGF in the PE group was lower. The area under curve (AUC) of sFlt-1, PLGF and sFlt-1/PLGF for predicting PE was 0.786, 0.719 and 0.866, respectively. Combined with Corin, the prediction ability of the above biomarkers could be improved to 0.876, 0.847, and 0.897, respectively. Corin in combination with sFlt-1/PLGF resulted in improvements with 12.6% being reclassified and a resulting NRI of 0.142 (0.020~0.263) and IDI of 0.087 (0.037~0.137).

Conclusion

The addition of Corin to sFlt-1, PLGF and sFlt-1/PLGF can improve the ability of each marker to predict PE risk. Corin in combination with sFlt-1/PLGF can be used as ideal markers to identify the pregnant women who subsequently develop PE, which will help in risk stratification and better therapeutic management.

Catechol-O-methyltransferase and Pregnancy Outcome: an Appraisal in Rat

Catechol-O-methyltransferase (COMT) has been shown to be a key regulator of pregnancy outcomes in mouse, and its deficiency is causative in the development of a preeclampsia-like disease process. Preeclampsia is a human pregnancy disorder associated with failure of intrauterine trophoblast cell invasion and trophoblast-guided uterine spiral artery remodeling, which are not well-developed in mouse. The purpose of this study was to investigate COMT in rat, a species with deep intrauterine trophoblast invasion. To accomplish this task, we used clustered regularly interspaced short palindromic repeats/Cas9-mediated genome editing of the rat Comt gene. A Comt null rat model was established and its fertility characterized. Comt null male and female rats were viable and fertile. COMT deficiency did not significantly impact pregnancy outcomes, including litter size, placental and fetal weights, Mendelian and sex ratios, or pregnancy-dependent adaptations to hypoxia. Collectively, our findings indicate that pregnancy-associated phenotypic outcomes of COMT deficiency are not equivalent in mouse and rat. In rat, COMT is not required for a successful pregnancy outcome.

Maternal DNA Methylation During Pregnancy: a Review

Multiple environmental, behavioral, and hereditary factors affect pregnancy. Recent studies suggest that epigenetic modifications, such as DNA methylation (DNAm), affect both maternal and fetal health during the period of gestation. Some of the pregnancy-related risk factors can influence maternal DNAm, thus predisposing both the mother and the neonate to clinical adversities with long-lasting consequences. DNAm alterations in the promoter and enhancer regions modulate gene expression changes which play vital physiological role. In this review, we have discussed the recent advances in our understanding of maternal DNA methylation changes during pregnancy and its associated complications such as gestational diabetes and anemia, adverse pregnancy outcomes like preterm birth, and preeclampsia. We have also highlighted some major gaps and limitations in the area which if addressed might improve our understanding of pregnancy and its associated adverse clinical conditions, ultimately leading to healthy pregnancies and reduction of public health burden.

VAL158MET catechol O-methyltransferase polymorphism contributes to the development of preeclampsia

Objectives: Establishment of association between: (a) Val158Met COMT (G1947A) polymorphism and preeclampsia; (b) cytokines gene expression and COMT genotypes. Methods: 50 preeclampsia and 50 healthy pregnant women were enrolled. COMT genotyping was done by PCR/RFLP. TNF-α, IL-1β, and IL-6 mRNA levels were determined by Real-time PCR. Results: Variant (AA) homozygotes carried 3.7-fold increased preeclampsia odds, especially for severe (OR = 9.0, 95%CI (2.09-38.799)) and early forms (OR = 6.6, 95%CI (1.62-26.87)). AA homozygotes with PE had higher TNF-α levels compared to controls (P = 0.012). Conclusions: Val158Met COMT polymorphism increases preeclampsia risk. TNF-α expression and Val158Met COMT polymorphism have concomitant roles in PE pathogenesis.

2-Methoxyestradiol Attenuates Angiotensin II-Induced Hypertension, Cardiovascular Remodeling, and Renal Injury

Estradiol may antagonize the adverse cardiovascular effects of angiotensin II (Ang II). We investigated the effects of 2-methoxyestradiol (2-ME), a nonestrogenic estradiol metabolite, on Ang II-induced cardiovascular and renal injury in male rats. First, we determined the effects of 2-ME on Ang II-induced acute changes in blood pressure, renal hemodynamics, and excretory function. Next, we investigated the effects of 2-ME and 2-hydroxyestardiol (2-HE) on hypertension and cardiovascular and renal injury induced by chronic infusion of Ang II. Furthermore, the effects of 2-ME on blood pressure and cardiovascular remodeling in the constricted aorta (CA) rat model and on isoproterenol-induced (ISO) cardiac hypertrophy and fibrosis were examined. 2-ME had no effects on Ang II-induced acute changes in blood pressure, renal hemodynamics, or glomerular filtration rate. Both 2-ME and 2-HE reduced hypertension, cardiac hypertrophy, proteinuria, and mesangial expansion induced by chronic Ang II infusions. In CA rats, 2-ME attenuated cardiac hypertrophy and fibrosis and reduced elevated blood pressure above the constriction. Notably, 2-ME reduced both pressure-dependent (above constriction) and pressure-independent (below constriction) vascular remodeling. 2-ME had no effects on ISO-induced renin release yet reduced ISO-induced cardiac hypertrophy and fibrosis. This study shows that 2-ME protects against cardiovascular and renal injury due to chronic activation of the renin-angiotensin system. This study reports for the first time that in vivo 2-ME reduces trophic (pressure-independent) effects of Ang II and related cardiac and vascular remodeling.

HIF-1α regulates angiogenesis via Notch1/STAT3/ETBR pathway in trophoblastic cells

Background: Preeclampsia is a pregnancy-related complication and the major cause to maternal and fetal mortality. Despite extensive studies, the pathogenesis of this disease still remains unknown. Here we explored the roles of HIF-1α and Notch1/ETBR in preeclampsia.Methods: Immunohistochemistry, RT-qPCR and western blot were used to measure levels of Notch1 and ETBR in placentas of preeclampsia patients. Transwell invasion assay and in vitro Matrigel assay were used to test the functions of Notch1, HIF-1α and ETBR in invasion and angiogenesis of trophoblast cells. In addition, we used reduced uterine perfusion pressure (RUPP) rat model to study preeclampsia in vivo.Results: We found that Notch1 and ETBR were down-regulated in the placenta of patients with preeclampsia. Hypoxia promoted invasion and angiogenesis of trophoblast cells, and up-regulated expressions of HIF-1α, Notch1/ETBR. Overexpression of Notch1 facilitated invasion and angiogenesis of trophoblast cells while HIF-1α inhibitor suppressed. Furthermore, Notch1 or ETBR could promote angiogenesis of trophoblast cells in RUPP rats.Conclusions: Our study reveals that HIF-1α and Notch1/ETBR play important roles in preeclampsia. Hypoxia-induced HIF-1αregulated Notch1/ETBR signaling, thereby modulating invasion and angiogenesis of trophoblast cells. These results shed light on molecular mechanisms of preeclampsia and provide potential targets for preeclampsia therapy.

Hypoxia-induced Downregulation of SRC-3 Suppresses Trophoblastic Invasion and Migration Through Inhibition of the AKT/mTOR Pathway: Implications for the Pathogenesis of Preeclampsia

Preeclampsia (PE) is characterized by poor placentation, consequent on aberrant extravillous trophoblast (EVT) cell function during placental development. The SRC family of proteins is important during pregnancy, especially SRC-3, which regulates placental morphogenesis and embryo survival. Although SRC-3 expression in mouse trophoblast giant cells has been documented, its role in the functional regulation of extravillous trophoblasts and the development of PE remains unknown. This study found that SRC-3 expression was significantly lower in placentas from PE pregnancies as compared to uncomplicated pregnancies. Additionally, both CoCl₂-mimicked hypoxia and suppression of endogenous SRC-3 expression by lentivirus short hairpin RNA attenuated the migration and invasion abilities of HTR-8/SVneo cells. Moreover, we demonstrated that SRC-3 physically interacts with AKT to regulate the migration and invasion of HTR-8 cells, via the AKT/mTOR pathway. We also found that the inhibition of HTR-8 cell migration and invasion by CoCl₂-mimicked hypoxia was through the SRC-3/AKT/mTOR axis. Our findings indicate that, in early gestation, accumulation of HIF-1α inhibits the expression of SRC-3, which impairs extravillous trophoblastic invasion and migration by directly interacting with AKT. This potentially leads to insufficient uterine spiral artery remodeling and placental hypoperfusion, and thus the development of PE.

Estrogen metabolism pathways in preeclampsia and normal pregnancy

BACKGROUND

Experimental studies suggest that shallow uterine cytotrophoblastic invasion in preeclampsia may be associated with alterations in estrogen metabolism. The objective of this study was to examine the association of parent estrogens and their metabolites between preeclamptics and normotensive controls at three time points during pregnancy. Methods Parent estrogens and their metabolites were measured in urine by high-performance liquid chromatography-tandem mass spectrometry in 66 singleton preeclampsia cases and 137 matched controls. Percent change in geometric means were estimated by general linear models adjusted for gestational age at sampling, maternal age, parity, race, body mass index, and use of assisted reproductive technologies. Results Urinary estradiol concentrations were approximately 50% higher in early pregnancy in preeclampsia cases than controls, but similar late in pregnancy. There was an approximate 20% reduction in total 2-pathway metabolites and 4-pathway metabolites in cases compared with controls in mid- and later pregnancy that was slightly attenuated with adjustment for BMI, and a reduction in 16-pathways in mid-pregnancy but not later. Conclusion(s) Our findings show that estradiol concentrations were elevated in preeclampsia versus controls in early pregnancy. In mid-pregnancy, all three estrogen metabolism (2-, 4-, and 16-) pathways showed some reduction in preeclampsia that appeared to continue for the 2- and 4-pathways in late pregnancy. We hypothesize that this may indicate that there is a generalized reduction in estrogen metabolism in preeclampsia rather than a deficit of specific enzymes, such as those involved in the 2-hydroxylation pathway.

Serotonin-estrogen interactions: What can we learn from pregnancy?

We have reviewed the scientific literature related to four diseases in which to serotonin (5-HT) is involved in the etiology, herein named 5-HT-linked diseases, and whose prevalence is influenced by estrogenic status: depression, migraine, irritable bowel syndrome and eating disorders. These diseases all have in common a sex-dimorphic prevalence, with women more frequently affected than men. The co-occurrence between these 5-HT-linked diseases suggests that they have common physiopathological mechanisms. In most 5-HT-linked diseases (except for anorexia nervosa and irritable bowel syndrome), a decrease in the serotonergic tone is observed and estrogens are thought to contribute to the improvement of symptoms by stimulating the serotonergic system. Human pregnancy is characterized by a unique 5-HT and estrogen synthesis by the placenta. Pregnancy-specific disorders, such as hyperemesis gravidarum, gestational diabetes mellitus and pre-eclampsia, are associated with a hyperserotonergic state and decreased estrogen levels. Fetal programming of 5-HT-linked diseases is a complex phenomenon that involves notably fetal-sex differences, which suggest the implication of sex steroids. From a mechanistic point of view, we hypothesize that estrogens regulate the serotonergic system, resulting in a protective effect against 5-HT-linked diseases, but that, in turn, 5-HT affects estrogen synthesis in an attempt to retrieve homeostasis. These two processes (5-HT and estrogen biosynthesis) are crucial for successful pregnancy outcomes, and thus, a disruption of this 5-HT-estrogen relationship may explain pregnancy-specific pathologies or pregnancy complications associated with 5-HT-linked diseases.

Loss of placental growth factor ameliorates maternal hypertension and preeclampsia in mice

Preeclampsia remains a clinical challenge due to its poorly understood pathogenesis. A prevailing notion is that increased placental production of soluble fms-like tyrosine kinase-1 (sFlt-1) causes the maternal syndrome by inhibiting proangiogenic placental growth factor (PlGF) and VEGF. However, the significance of PlGF suppression in preeclampsia is uncertain. To test whether preeclampsia results from the imbalance of angiogenic factors reflected by an abnormal sFlt-1/PlGF ratio, we studied PlGF KO (Pgf-/-) mice and noted that the mice did not develop signs or sequelae of preeclampsia despite a marked elevation in circulating sFLT-1. Notably, PlGF KO mice had morphologically distinct placentas, showing an accumulation of junctional zone glycogen. We next considered the role of placental PlGF in an established model of preeclampsia (pregnant catechol-O-methyltransferase-deficient [COMT-deficient] mice) by generating mice with deletions in both the Pgf and Comt genes. Deletion of placental PlGF in the context of COMT loss resulted in a reduction in maternal blood pressure and increased placental glycogen, indicating that loss of PlGF might be protective against the development of preeclampsia. These results identify a role for PlGF in placental development and support a complex model for the pathogenesis of preeclampsia beyond an angiogenic factor imbalance.

Association of 2-Methoxyestradiol (2ME) Plasma Levels with Clinical Severity Indices and Biomarkers of Preeclampsia

Introduction

Preeclampsia is an important cause of maternal and perinatal morbidity and mortality. The pathophysiology of preeclampsia has been extensively studied. 2ME seems to maintain placental homeostasis necessary for appropriate cytotrophoblast invasion of the maternal deciduas. We plan this study to compare its value in the plasma of normotensive and preeclamptic women and studying its correlation with the severity indices of preeclampsia.

Aim and Objectives

The aim of this study was to estimate plasma levels of 2ME in preeclamptic and normotensive pregnant women and correlate it with the severity in terms of clinical indices, laboratory investigations, and fetomaternal outcome.

Materials and Methods

This study was a case-control study conducted in KGMU, Lucknow, August 2015-2016. Sample size was 90 pregnant women including 30 normotensive, 30 non-severe preeclampsia, and 30 severe preeclampsia patients. Plasma 2ME levels were analyzed using ELISA kit and the outcome was compared in terms of systolic and diastolic blood pressure, proteinuria, liver and renal function tests, serum LDH, uric acid, plasma 2ME levels, and fetomaternal outcome.

Results

There was a significant (p = 0.0001) difference in 2ME plasma levels among the groups (normotensive, non severe and severe preeclampsia patients). 2ME plasma levels significantly negatively correlated with SBP (r = - 0.62, p = 0.0001) and DBP (r = - 0.63, p = 0.0001). With one-unit increase in SBP, 2ME will decrease by 2445.14 units, and in one-unit increase in DBP, 2ME will decrease by 1807.28 units. The sensitivity and specificity of 2ME for preeclampsia were found to be high.

Conclusion

It was seen that there was a statistically significant difference between plasma 2ME levels among the three groups. The ROC curve obtained showed that sensitivity was predicted to be 98.3%, specificity 76.7%, positive predictive value of 89.4%, negative predictive value of 95.8% and accuracy of 91.1%.

From Pregnancy to Preeclampsia: A Key Role for Estrogens

Preeclampsia (PE) results in placental dysfunction and is one of the primary causes of maternal and fetal mortality and morbidity. During pregnancy, estrogen is produced primarily in the placenta by conversion of androgen precursors originating from maternal and fetal adrenal glands. These processes lead to increased plasma estrogen concentrations compared with levels in nonpregnant women. Aberrant production of estrogens could play a key role in PE symptoms because they are exclusively produced by the placenta and they promote angiogenesis and vasodilation. Previous assessments of estrogen synthesis during PE yielded conflicting results, possibly because of the lack of specificity of the assays. However, with the introduction of reliable analytical protocols using liquid chromatography/mass spectrometry or gas chromatography/mass spectrometry, more recent studies suggest a marked decrease in estradiol levels in PE. The aim of this review is to summarize current knowledge of estrogen synthesis, regulation in the placenta, and biological effects during pregnancy and PE. Moreover, this review highlights the links among the occurrence of PE, estrogen biosynthesis, angiogenic factors, and cardiovascular risk factors. A close link between estrogen dysregulation and PE occurrence might validate estrogen levels as a biomarker but could also reveal a potential approach for prevention or cure of PE.

A Comparison of 2-Methoxyestradiol Value in Women with Severe Preeclampsia Versus Normotensive Pregnancy

INTRODUCTION

Preeclampsia is a pregnancy complication characterized by high blood pressure and proteinuria. Endothelial dysfunction is a major theory suggested as its aetiology. It is caused by anti-angiogenic condition characterized by low Vascular Endothelial Growth Factor (VEGF). An estradiol metabolite, called 2-Methoxy Estradiol (2-ME), is produced with the help of Catechol-O-Methyltransferase (COMT). This substance has an important role in VEGF expression. A 2-ME is suppressed in women with preeclampsia.

AIM

To compare 2-ME in women with severe preeclampsia and normotensive pregnancy.

MATERIALS AND METHODS

A total of 80 subjects qualified the inclusion and exclusion criteria, were divided into two groups (40 each): the severe preeclampsia and the normotensive pregnancy. Blood sample was collected and examined with the ELISA 2-ME kit (Cayman). The data were compared and calculated using Fisher-Exact test to examine 2-ME differences between the two groups.

RESULTS

Women age, parity, and gestational age showed a non significant difference between both groups. Nonetheless, the BMI before pregnancy and the history of preeclampsia in the past pregnancy showed significant differences. In this study, the 2-ME value was lower in the severe preeclampsia group compared to the normotensive.

CONCLUSION

This study concludes that 2-ME value in severe preeclampsia is lower than normotensive pregnancy. A lower 2-ME value may indicate COMT not producing enough 2-ME which in turn may cause the pre-eclampsia.

Primate-specific miR-515 family members inhibit key genes in human trophoblast differentiation and are upregulated in preeclampsia

Dysregulation of human trophoblast invasion and differentiation can result in preeclampsia (PE), a hypertensive disorder of pregnancy with significant morbidity and mortality for mother and offspring. miRNA microarray analysis of RNA from human cytotrophoblasts (CytT), before and after differentiation to syncytiotrophoblast (SynT) in primary culture, revealed that members of miR-515 family-including miR-515-5p, miR-519e-5p, miR-519c-3p, and miR-518f, belonging to the primate- and placenta-specific chromosome 19 miRNA cluster (C19MC)-were significantly down-regulated upon human SynT differentiation. The proto-oncogene, c-MYC, which declines during SynT differentiation, interacted with E-boxes upstream of pri-miR-515-1 and pri-miR-515-2, encoding these mRNAs, to enhance their expression. Predicted targets of miR-515-5p, known to be critical for human SynT differentiation, including hCYP19A1/aromatase P450, glial cells missing 1 (GCM1), frizzled 5 (FZD5), WNT2, Sp1, and estrogen receptor-α (ERα) mRNA, were markedly up-regulated during SynT differentiation. Notably, overexpression of miR-515-5p in cultured primary human trophoblasts impaired SynT differentiation and specifically decreased expression of hCYP19A1, GCM1, and Fzd5, which were validated as its direct targets. Interestingly, miR-515-5p levels were significantly increased in PE placentas, whereas mRNA and protein levels of targets, hCYP19A1, GCM1, and FZD5, were significantly decreased, compared with placentas of normotensive women. Thus, miR-515-5p may serve a key role in human trophoblast differentiation; its aberrant up-regulation may contribute to the pathogenesis of PE.

Association between COMT Val158Met polymorphism and preeclampsia in the Chinese Han population

OBJECTIVE

Previous studies have been indicated that catechol-O-methyltransferase gene (COMT) might play a significant role in the development of preeclampsia (PE). Our study aims to investigate the association between polymorphism in COMT with the susceptibility to PE in Chinese Han women.

METHOD

A total of 1028 PE patients and 1399 normal pregnant women were enrolled. We detected the genotyping of COMT Val158Met loci by the TaqMan allelic discrimination real-time PCR .

RESULTS

No significant difference in the genotypic and allelic distribution was found between the two groups (genotype: X² = 0.583, p = 0.747; allele:X² = 0.526, p = 0.468).

CONCLUSION

The COMT Val158Met polymorphism might not be associated with PE in Chinese women.

Association between the maternal serum levels of 19 eicosanoids and pre-eclampsia

OBJECTIVE

To investigate whether serum levels of 19 eicosanoids are associated with pre-eclampsia.

METHODS

A case-control study was performed using data for pregnant women with pre-eclampsia, normotensive pregnant women, and nonpregnant women, for all of whom serum samples had been collected at a hospital in Shanghai, China, between December 2012 and December 2013. Ultra-performance liquid chromatography-tandem mass spectrometry was used to measure the serum levels of 19 eicosanoids.

RESULTS

Overall, 49 pregnant women with pre-eclampsia, 26 normotensive pregnant women, and 14 nonpregnant women were included. Women with pre-eclampsia had significantly higher serum levels of 11,12-epoxyeicosatrienoic acid (11,12-EET), the hydroxyeicosatetraenoic acids 5-HETE, 8-HETE, 12-HETE, and 15-HETE, and leukotriene B4 than did women with a normal pregnancy and nonpregnant women, both before and after the onset of pre-eclampsia (P<0.01 for all comparisons). Women with severe pre-eclampsia had significantly higher serum levels of 5-HETE, 15-HETE, and leukotriene B4 than did women with mild pre-eclampsia, women with a normal pregnancy, and nonpregnant women (P<0.01 for all comparisons).

CONCLUSION

The eicosanoids 11,12-EET, 5-HETE, 8-HETE, 12-HETE, 15-HETE, and leukotriene B4 might play important parts in the occurrence and development of pre-eclampsia.

Effects of oxygen tension and dextran-shelled/2H,3H-decafluoropentane-cored oxygen-loaded nanodroplets on secretion of gelatinases and their inhibitors in term human placenta

Matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) need to be finely modulated in physiological processes. However, oxygen tension influences MMP/TIMP balances, potentially leading to pathology. Intriguingly, new 2H,3H-decafluoropentane-based oxygen-loaded nanodroplets (OLNDs) have proven effective in abrogating hypoxia-dependent dysregulation of MMP and TIMP secretion by single cell populations. This work explored the effects of different oxygen tensions and dextran-shelled OLNDs on MMP/TIMP production in an organized and multicellular tissue (term human placenta). Chorionic villous explants from normal third-trimester pregnancies were incubated with/without OLNDs in 3 or 20% O2. Explants cultured at higher oxygen tension released constitutive proMMP-2, proMMP-9, TIMP-1, and TIMP-2. Hypoxia significantly altered MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios enhancing TIMP-2 and reducing proMMP-2, proMMP-9, and TIMP-1 levels. Intriguingly, OLNDs effectively counteracted the effects of low oxygen tension. Collectively, these data support OLND potential as innovative, nonconventional, and cost-effective tools to counteract hypoxia-dependent dysregulation of MMP/TIMP balances in human tissues.

Maternal plasma TIMP-4 levels combined with clinical risk factors for the early prediction of pregnancy-induced hypertension

OBJECTIVE

The objective of this study was to create a model for early predicting pregnancy-induced hypertension (PIH) using plasma markers and clinical risk factors.

METHODS

A nested case-control study was performed at the Laboratory Department of Guangzhou Women and Children's Medical Center. From a prospective cohort of tens of thousands of unselected women with singleton pregnancies at 8-20 weeks gestation, maternal plasma samples were obtained from 73 women who subsequently developed PIH (PIH group) and 146 gestational age- and maternal age-matched women with normotensive pregnancies (control group). Proteins extracted from the plasma samples were screened by microchip and verified by ELISA. Clinical risk factor data were analyzed retrospectively.

RESULTS

Compared to the control group, high concentrations of tissue inhibitor of metalloproteinase-4 (TIMP-4) were found in women with PIH (P = 0.000). Univariate risk factor analysis identified three variables with significant differences between the groups: family history of PIH (P = 0.031), body mass index (BMI; P < 0.001), and non-glucose-6-phosphate dehydrogenase deficiency-induced anemia (P < 0.027). Multiple regression analyses revealed a significant relationship of PIH with TIMP-4 levels, BMI, and family history (combined area under the receiver operating characteristic curve = 0.820).

CONCLUSION

Upregulation of plasma TIMP-4 might contribute to PIH processes. Potential risk factors of this disease may include a family history of PIH and BMI. The combination of TIMP-4 levels and these risk factors may have some predictive values for PIH. Future multicenter studies including greater numbers of samples, analyzed proteins, and risk factors are needed to obtain a higher predictive value of the model for the clinical diagnosis of PIH.

Fetal Val108/158Met catechol-O-methyltransferase (COMT) polymorphism and placental COMT activity are associated with the development of preeclampsia

OBJECTIVE

To evaluate the association between fetal and maternal catechol-O-methyltransferase (COMT) Val158Met and methyl tetrahydrofolate reductase (MTHFR) C677T functional polymorphisms and preeclampsia, examining its influence on placental COMT and in maternal 2-methoxyestradiol (2-ME) plasma levels.

DESIGN

Prospective case-control study.

SETTING

University hospital.

PATIENT(S)

A total of 53 preeclamptic and 72 normal pregnant women.

INTERVENTION(S)

Maternal and cord blood samples and placental tissue samples were obtained.

MAIN OUTCOME MEASURE(S)

Maternal and fetal COMT and MTHFR polymorphisms were genotyped. Maternal plasma 2-ME and homocysteine levels, and expression and activity of placental COMT were measured.

RESULT(S)

The odds ratio for the risk of preeclampsia for fetal COMT Met/Met was 3.22, and it increased to 8.65 when associated with fetal MTHFR TT. Placental COMT activity and expression were influenced by genotype, but COMT activity in preeclamptic placentas did not differ from control pregnancies. There was no association between any genotypes and maternal 2-ME. Homocysteine levels were higher in women with preeclampsia than in normal pregnancies, and were inversely correlated with 2-ME plasma levels, indicating that its altered metabolism may lower COMT activity in vivo.

CONCLUSION(S)

Fetal Met-Met COMT genotype reduces COMT placental expression and activity in vitro and increases preeclampsia, risk but it does not explain the difference in maternal 2-ME levels between preeclamptic and normal pregnancies. However, the preeclamptic patients had elevated homocysteine levels that correlated inversely with 2-ME, indicating that an altered methionine-homocysteine metabolism may contribute to reduce COMT activity in vivo and explain the decreased levels of 2-ME in preeclamptic women.

Placental Aromatase Is Deficient in Placental Ischemia and Preeclampsia

Introduction

Preeclampsia is a maternal hypertensive disorder with uncertain etiology and a leading cause of maternal and fetal mortality worldwide, causing nearly 40% of premature births delivered before 35 weeks of gestation. The first stage of preeclampsia is characterized by reduction of utero-placental blood flow which is reflected in high blood pressure and proteinuria during the second half of pregnancy. In human placenta androgens derived from the maternal and fetal adrenal glands are converted into estrogens by the enzymatic action of placental aromatase. This implies that alterations in placental steroidogenesis and, subsequently, in the functionality or bioavailability of placental aromatase may be mechanistically involved in the pathophysiology of PE.

Methods

Serum samples were collected at 32–36 weeks of gestation and placenta biopsies were collected at time of delivery from PE patients (n = 16) and pregnant controls (n = 32). The effect of oxygen tension on placental cells was assessed by incubation JEG–3 cells under 1% and 8% O₂ for different time periods, Timed-mated, pregnant New Zealand white rabbits (n = 6) were used to establish an in vivo model of placental ischemia (achieved by ligature of uteroplacental vessels). Aromatase content and estrogens and androgens concentrations were measured.

Results

The protein and mRNA content of placental aromatase significantly diminished in placentae obtained from preeclamptic patients compared to controls. Similarly, the circulating concentrations of 17-β-estradiol/testosterone and estrone/androstenedione were reduced in preeclamptic patients vs. controls. These data are consistent with a concomitant decrease in aromatase activity. Aromatase content was reduced in response to low oxygen tension in the choriocarcinoma JEG–3 cell line and in rabbit placentae in response to partial ligation of uterine spiral arteries, suggesting that reduced placental aromatase activity in preeclamptic patients may be associated with chronic placental ischemia and hypoxia later in gestation.

Conclusions

Placental aromatase expression and functionality are diminished in pregnancies complicated by preeclampsia in comparison with healthy pregnant controls.

Neuronal Nitric Oxide Synthase-Mediated Genotoxicity of 2-Methoxyestradiol in Hippocampal HT22 Cell Line

2-methoxyestradiol, metabolite of 17β-estradiol, is considered a potential anticancer agent, currently investigated in several clinical trials. This natural compound was found to be effective towards great number of cancers, including colon, breast, lung, and osteosarcoma and has been reported to be relatively non-toxic towards non-malignant cells. The aim of the study was to determine the potential neurotoxicity and genotoxicity of 2-methoxyestradiol at physiological and pharmacological relevant concentrations in hippocampal HT22 cell line. Herein, we determined influence of 2-methoxyestradiol on proliferation, inhibition of cell cycle, induction of apoptosis, and DNA damage in the HT22 cells. The study was performed using imaging cytometry and comet assay techniques. Herein, we demonstrated that 2-methoxyestradiol, at pharmacologically and also physiologically relevant concentrations, increases nuclear localization of neuronal nitric oxide synthase. It potentially results in DNA strand breaks and increases in genomic instability in hippocampal HT22 cell line. Thus, we are postulating that naturally occurring 2-methoxyestradiol may be considered a physiological modulator of neuron survival.

The importance of MTHFR, MTR, MTRR and CSE expression levels in Caucasian women with preeclampsia

OBJECTIVE

Preeclampsia (PE) is a major cause of maternal and perinatal mortality and morbidity. The studies suggest that both polymorphisms and changes of expression in genes encoding enzymes involved in the methionine and homocysteine metabolism (MHM), such as methylenetetrahydrofolate, reductase (MTHFR), methionine synthase (MTR), methionine synthase reductase (MTRR) and cystathionine gamma-lyase (CSE), could play a role in the development of hypertension during pregnancy. The aim of the study was to determine the expression level of MTHFR, MTR, MTRR and CSE genes in the development of PE in Caucasian women.

STUDY DESIGN

The control group consisted of 74 healthy pregnant women and 90 patients with diagnosed pre-eclampsia. Total RNA was isolated from placenta and the mRNA level of examined genes was to determine using real-time PCR.

RESULTS

The expression level of MTHFR gene showed no statistically significant difference in the study group as compared to the control group. An increase of mRNA levels for MTR and CTH was observed by 124.7% (p<0.0001) and 26.6% (p>0.05), respectively. However, a decrease of placental expression was noted for MTRR by 50% in preeclamptic women as compared to control group (p<0.0001).

CONCLUSIONS

Our findings suggest that the elevated RNA expression of MTR in placenta of preeclamptic patients is probably results of a potential compensation mechanism of the MHM while elevated CSE expression indicates that homocysteine may be eliminated through the alternate transsulfuration pathway.

Adaptive mechanisms controlling uterine spiral artery remodeling during the establishment of pregnancy

Implantation of the embryo into the uterus triggers the initiation of hemochorial placentation. The hemochorial placenta facilitates the acquisition of maternal resources required for embryo/fetal growth. Uterine spiral arteries form the nutrient supply line for the placenta and fetus. This vascular conduit undergoes gestation stage-specific remodeling directed by maternal natural killer cells and embryo-derived invasive trophoblast lineages. The placentation site, including remodeling of the uterine spiral arteries, is shaped by environmental challenges. In this review, we discuss the cellular participants controlling pregnancy-dependent uterine spiral artery remodeling and mechanisms responsible for their development and function.

The relevance of the Renin-Angiotensin system in the development of drugs to combat preeclampsia

Preeclampsia is a hypertensive disorder that occurs during pregnancy. It has an unknown etiology and affects approximately 5-8% of pregnancies worldwide. The pathophysiology of preeclampsia is not yet known, and preeclampsia has been called "a disease of theories." The central symptom of preeclampsia is hypertension. However, the etiology of the hypertension is unknown. In this review, we analyze the molecular mechanisms of preeclampsia with a particular focus on the pathogenesis of the hypertension in preeclampsia and its association with the renin-angiotensin system. In addition, we propose potential alternative strategies to target the renin-angiotensin system, which is enhanced during pregnancy.

2-methoxyestradiol plasma levels are associated with clinical severity indices and biomarkers of preeclampsia

We investigated whether clinical severity indices and biomarkers for preeclampsia (PE) are associated with low plasmatic 2-methoxyestradiol (2ME) in the third trimester of gestation. Blood was collected from 53 women with PE and 73 control pregnant women before parturition. The concentration of 2ME was significantly higher in controls than in patients with PE (2906.43 ± 200.69 pg/mL vs 1818.41 ± 189.25 pg/mL). The risk of PE decreased as 2ME levels increased. The 2ME values were negatively correlated with systolic peak arterial pressure and proteinuria in PE. Additionally, those women with PE with lower 2ME had a more serious clinical situation and needed a more aggressive therapy. Finally, 2ME levels (in patients with PE and total population) were significantly correlated with concentrations of soluble fms-like tyrosine kinase 1 and placental growth factor . Summarizing, patients with PE had lower 2ME levels that were correlated with different clinical indices and biomarkers of severity, indicating that 2ME could be taken into account for the clinical management of this syndrome.

2-Methoxyestradiol deficiency is strongly related to hypertension in early onset severe pre-eclampsia

OBJECTIVE

2-Methoxyestradiol (2ME) deficiency leading to placental insufficiency has been related to pre-eclampsia (PE). Here we investigate whether 2ME is related to clinical profiles and vasoactive factors in early onset severe PE patients.

METHODS

28 severe PE patients and 20 uncomplicated normal pregnant women, with gestational weeks between 24 and 32weeks, were recruited. All cases and controls had singleton pregnancies and were matched for maternal age, parity, body mass index, and gestational weeks. Plasma levels of 2ME, estradiol (E2), soluble Fms-like tyrosine kinase-1 (sFLT-1), endothelin-1 (ET-1), nitric oxide (NO) were determined.

RESULTS

PE patients had significant lower 2ME [906(422-1768) vs. 2032(1400-2910)pg/mL, P=0.002], higher sFLT-1 [5.55(3.24-11.22) vs. 3.13(2.17-5.36)ng/mL, P=0.015] and higher NO [122.40(72.92-168.23) vs. 45.83(25.52-61.46)μmol/L, P=0.0008] levels in their plasma than the controls. In the PE group, plasma 2ME level correlated negatively with systolic pressure (r=-0.48, P=0.012), diastolic pressure (r=-0.52, P=0.007) and mean arterial pressure (r=-0.54, P=0.005) even after controlling for maternal age; 2ME level did not correlate with proteinuria, plasma levels of E2, sFLT-1, ET-1 or NO. In the control group, plasma 2ME level did not correlate with any of the above clinical profiles or laboratory measurements.

CONCLUSIONS

2ME levels were markedly lower in early onset severe PE and they correlated inversely with blood pressure only in women with PE. Although we cannot tell whether lower 2ME level is the causation or the result of PE, our study provides clinical evidences that 2ME deficiency is strongly related to hypertension in early onset severe PE patients.

2-methoxyestradiol and disorders of female reproductive tissues

2-Methoxyestradiol (2ME) is an endogenous metabolite of 17β-estradiol. Once thought of as a mere degradation product, 2ME has gained attention as an important component of reproductive physiology and as a therapeutic agent in reproductive pathologies such as preeclampsia, endometriosis, infertility, and cancer. In this review, we discuss the involvement of 2ME in reproductive pathophysiology and summarize its known mechanisms of action: microtubule disruption, inhibition of angiogenesis and stimulation of apoptosis. Currently, the clinical uses of 2ME as a single agent are limited due to its poor water solubility and thus low bioavailability; however, 2ME analogs and derivatives have been recently developed and tested as cancer treatments. Despite some isolated success stories and ongoing research, 2ME derivatives have not yet provided the expected results. The adjuvant use of 2ME derivatives with chemotherapeutic agents is hindered by their intrinsic toxicity confounding the unwanted secondary effects of chemotherapy. However, due to the well-tested tolerance of the body to high doses of native 2ME, it may the combination of native 2ME with conventional treatments that will offer novel clinically relevant regimens for cancer and other reproductive disorders.

Association of COMT G675A and MTHFR C677T polymorphisms with hypertensive disorders of pregnancy in Mexican mestizo population

OBJECTIVE

To investigate the relationship between COMT G675A and MTHFR C677T polymorphisms and hypertension disorders of pregnancy (HDP) in a Mexican mestizo population.

DESIGN AND METHODS

This case-control study involved 194 HDP and 194 normoevolutive pregnant women. The polymorphisms were genotyped by real time PCR.

RESULTS

Our results showed that the COMT AA genotype increases the risk to HDP (OR: 2.67; 95% CI 1.33-5.35), preeclampsia (OR: 2.69; 95% CI 1.00-7.22) and gestational hypertension (OR: 3.87; 95% CI 1.25-12.0). Furthermore, the double mutant genotype (COMTAA/MTHFRTT) potency the risk to HDP more than two times (OR: 5.21; 95% CI 1.12-24.3, p=0.019).

CONCLUSION

Our work provides evidence that COMT 675AA genotype is a risk factor for HDP and that this risk is increased by the presence of MTHFR 677TT genotype in a Mexican mestizo population.

Proteomic analysis on the alteration of protein expression in the early-stage placental villous tissue of electromagnetic fields associated with cell phone exposure

BACKGROUND

To explore the possible adverse effects and search for cell phone electromagnetic field (EMF)-responsive proteins in human early reproduction, a proteomics approach was employed to investigate the changes in protein expression profile induced by cell phone EMF in human chorionic tissues of early pregnancy in vivo.

METHODS

Volunteer women about 50 days pregnant were exposed to EMF at the average absorption rate of 1.6 to 8.8 W/kg for 1 hour with the irradiation device placed 10 cm away from the umbilicus at the midline of the abdomen. The changes in protein profile were examined using 2-dimensional electrophoresis (2-DE).

RESULTS

Up to 15 spots have yielded significant change at least 2- to 2.5-folds up or down compared to sham-exposed group. Twelve proteins were identified- procollagen-proline, eukaryotic translation elongation factor 1 delta, chain D crystal structure of human vitamin D-binding protein, thioredoxin-like 3, capping protein, isocitrate dehydrogenase 3 alpha, calumenin, Catechol-O-methyltransferase protein, proteinase inhibitor 6 (PI-6; SerpinB6) protein, 3,2-trans-enoyl-CoA isomerase protein, chain B human erythrocyte 2,3-bisphosphoglycerate mutase, and nucleoprotein.

CONCLUSION

Cell phone EMF might alter the protein profile of chorionic tissue of early pregnancy, during the most sensitive stage of the embryos. The exposure to EMF may cause adverse effects on cell proliferation and development of nervous system in early embryos. Furthermore, 2-DE coupled with mass spectrometry is a promising approach to elucidate the effects and search for new biomarkers for environmental toxic effects.

Levels of key enzymes of methionine-homocysteine metabolism in preeclampsia

OBJECTIVE

To evaluate the role of key enzymes in the methionine-homocysteine metabolism (MHM) in the physiopathology of preeclampsia (PE).

METHODS

Plasma and placenta from pregnant women (32 controls and 16 PE patients) were analyzed after informed consent. Protein was quantified by western blot. RNA was obtained with RNA purification kit and was quantified by reverse transcritase followed by real-time PCR (RT-qPCR). Identification of the C677T and A1298C methylenetetrahydrofolate reductase (MTHFR) single-nucleotide polymorphisms (SNPs) and A2756G methionine synthase (MTR) SNP was performed using PCR followed by a high-resolution melting (HRM) analysis. S-adenosyl methionine (SAM) and S-adenosyl homocysteine (SAH) were measured in plasma using high-performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS). The SNP association analysis was carried out using Fisher's exact test. Statistical analysis was performed using a Mann-Whitney test.

RESULTS

RNA expression of MTHFR and MTR was significantly higher in patients with PE as compared with controls. Protein, SAM, and SAH levels showed no significant difference between preeclamptic patients and controls. No statistical differences between controls and PE patients were observed with the different SNPs studied.

CONCLUSION

The RNA expression of MTHFR and MTR is elevated in placentas of PE patients, highlighting a potential compensation mechanism of the methionine-homocysteine metabolism in the physiopathology of this disease.

Gestational hypoxia induces preeclampsia-like symptoms via heightened endothelin-1 signaling in pregnant rats

Preeclampsia is a life-threatening pregnancy disorder. However, its pathogenesis remains unclear. We tested the hypothesis that gestational hypoxia induces preeclampsia-like symptoms via heightened endothelin-1 (ET-1) signaling. Time-dated pregnant and nonpregnant rats were divided into normoxic and hypoxic (10.5% O2 from the gestational day 6-21) groups. Chronic hypoxia had no significant effect on blood pressure or proteinuria in nonpregnant rats but significantly increased blood pressure on day 12 (systolic blood pressure, 111.7 ± 6.1 versus 138.5 ± 3.5 mm Hg; P=0.004) and day 20 (systolic blood pressure, 103.4 ± 4.6 versus 125.1 ± 6.1 mm Hg; P=0.02) in pregnant rats and urine protein (μg/μL)/creatinine (nmol/μL) ratio on day 20 (0.10 ± 0.01 versus 0.20 ± 0.04; P=0.04), as compared with the normoxic control group. This was accompanied with asymmetrical fetal growth restriction. Hypoxia resulted in impaired trophoblast invasion and uteroplacental vascular remodeling. In addition, plasma ET-1 levels, as well as the abundance of prepro-ET-1 mRNA, ET-1 type A receptor and angiotensin II type 1 receptor protein in the kidney and placenta were significantly increased in the chronic hypoxic group, as compared with the control animals. Treatment with the ET-1 type A receptor antagonist, BQ123, during the course of hypoxia exposure significantly attenuated the hypoxia-induced hypertension and other preeclampsia-like features. The results demonstrate that chronic hypoxia during gestation induces preeclamptic symptoms in pregnant rats via heightened ET-1 and ET-1 type A receptor-mediated signaling, providing a molecular mechanism linking gestational hypoxia and increased risk of preeclampsia.

Downregulated Krüppel-like factor 8 is involved in decreased trophoblast invasion under hypoxia-reoxygenation conditions

Krüppel-like factor 8 (KLF8) is a pivotal transcription factor expressed in the human placenta that can regulate cell invasion. The objective of this study was to assess whether a hypoxia-reoxygenation (H/R) environment affects placental KLF8 expression levels and subcellular localization and to evaluate the relationship between KLF8 levels and trophoblast invasion activity. Human first trimester villous tissues from normal pregnancies and third trimester placentas from pregnancies with or without preeclampsia (PE) were used for the detection of KLF8 expression and correlating its levels with metalloproteinase 9 (MMP-9) expression. In addition, HTR8/SVneo cells were used to mimic the effects of an H/R environment on placentas to study KLF8 expression and trophoblast invasion. The KLF8 levels, MMP-9 levels, and trophoblast invasion were similarly altered; the levels peaked at 8 to 10 weeks of gestation and declined thereafter along with oxygen tension increased from hypoxia to normoxia during early pregnancy, decreased in third trimester placentas from PE pregnancies featured by repeated H/R and HTR8/SVneo cells exposed to H/R compared with the control. Moreover, a visible reduction in KLF8 immunoreactivity was present in the nuclei of cytotrophoblast cells in human villous tissues at 11 weeks, and partial cytoplasmic accumulation of KLF8 was observed in HTR8/SVneo cells treated with H/R. In conclusion, these findings strongly suggest that H/R reduces the expression and nuclear localization of KLF8 to inhibit the trophoblast invasion by downregulating MMP-9 levels. The KLF8 may play a vital role in the pathogenesis of PE as a novel oxygen tension sensor.

Pro-inflammatory profile of preeclamptic placental mesenchymal stromal cells: new insights into the etiopathogenesis of preeclampsia

The objective of the present study was to evaluate whether placental mesenchymal stromal cells (PDMSCs) derived from normal and preeclamptic (PE) chorionic villous tissue presented differences in their cytokines expression profiles. Moreover, we investigated the effects of conditioned media from normal and PE-PDMSCs on the expression of pro-inflammatory Macrophage migration Inhibitory Factor (MIF), Vascular Endothelial Growth Factor (VEGF), soluble FMS-like tyrosine kinase-1 (sFlt-1) and free β-human Chorionic Gonadotropin (βhCG) by normal term villous explants. This information will help to understand whether anomalies in PE-PDMSCs could cause or contribute to the anomalies typical of preeclampsia.

METHODS

Chorionic villous PDMSCs were isolated from severe preeclamptic (n = 12) and physiological control term (n = 12) placentae. Control and PE-PDMSCs's cytokines expression profiles were determined by Cytokine Array. Control and PE-PDMSCs were plated for 72 h and conditioned media (CM) was collected. Physiological villous explants (n = 48) were treated with control or PE-PDMSCs CM for 72 h and processed for mRNA and protein isolation. MIF, VEGF and sFlt-1 mRNA and protein expression were analyzed by Real Time PCR and Western Blot respectively. Free βhCG was assessed by immunofluorescent.

RESULTS

Cytokine array showed increased release of pro-inflammatory cytokines by PE relative to control PDMSCs. Physiological explants treated with PE-PDMSCs CM showed significantly increased MIF and sFlt-1 expression relative to untreated and control PDMSCs CM explants. Interestingly, both control and PE-PDMSCs media induced VEGF mRNA increase while only normal PDMSCs media promoted VEGF protein accumulation. PE-PDMSCs CM explants released significantly increased amounts of free βhCG relative to normal PDMSCs CM ones.

CONCLUSIONS

Herein, we reported elevated production of pro-inflammatory cytokines by PE-PDMSCs. Importantly, PE PDMSCs induced a PE-like phenotype in physiological villous explants. Our data clearly depict chorionic mesenchymal stromal cells as central players in placental physiopathology, thus opening to new intriguing perspectives for the treatment of human placental-related disorders as preeclampsia.

Metabolic pathways involved in 2-methoxyestradiol synthesis and their role in preeclampsia

Preeclampsia (PE) remains a major cause of maternal/fetal morbidity-mortality worldwide. The first stage of PE is characterized by placental hypoxia due to a relative reduction in uteroplacental blood flow, resulting from restricted trophoblast invasion. However, hypoxia is also an essential element for the success of invasion. Under hypoxic conditions, 2-methoxyestradiol (2-ME) could induce the differentiation of cytotrophoblast cells into an invasive phenotype in culture. 2-Methoxyestradiol is generated by catechol-O-methyltransferase, an enzyme involved in the metabolic pathway of estrogens. During pregnancy, circulating 2-ME levels increase significantly when compared to the menstrual cycle. Interestingly, plasma levels of 2-ME are lower in women with PE than in controls, and these differences are apparent weeks or even months before the clinical manifestations of the disease. This article reviews the metabolic pathways involved in 2-ME synthesis and discusses the roles of these pathways in normal and abnormal pregnancies, with particular emphasis on PE.

The c-Myc-regulated microRNA-17~92 (miR-17~92) and miR-106a~363 clusters target hCYP19A1 and hGCM1 to inhibit human trophoblast differentiation

Mononuclear cytotrophoblasts of the human placenta proliferate rapidly, subsequently fuse, and differentiate to form multinucleated syncytiotrophoblast with induction of aromatase (hCYP19A1) and chorionic gonadotropin (hCGβ) expression. Using microarray analysis, we identified members of the miR-17~92 cluster and its paralogs, miR-106a~363 and miR-106b~25, that are significantly downregulated upon syncytiotrophoblast differentiation. Interestingly, miR-19b and miR-106a directly targeted hCYP19A1 expression, while miR-19b also targeted human GCM1 (hGCM1), a transcription factor critical for mouse labyrinthine trophoblast development. Overexpression of these microRNAs (miRNAs) impaired syncytiotrophoblast differentiation. hGCM1 knockdown decreased hCYP19A1 and hCGβ expression, substantiating its important role in human trophoblast differentiation. Expression of the c-Myc proto-oncogene was increased in proliferating cytotrophoblasts compared to that in differentiated syncytiotrophoblast. Moreover, c-Myc overexpression upregulated miR-17~92 and inhibited hCYP19A1 and hCGβ expression. Binding of endogenous c-Myc to genomic regions upstream of the miR-17~92 and miR-106a~363 clusters in cytotrophoblasts dramatically decreased upon syncytiotrophoblast differentiation. Intriguingly, we observed higher levels of miR-106a and -19b and lower aromatase and hGCM1 expression in placentas from preeclamptic women than in placentas from gestation-matched normotensive women. Our findings reveal that c-Myc-regulated members of the miR-17~92 and miR-106a~363 clusters inhibit trophoblast differentiation by repressing hGCM1 and hCYP19A1 and suggest that aberrant regulation of these miRNAs may contribute to the pathogenesis of preeclampsia.