Emerging role for dysregulated decidualization in the genesis of preeclampsia

Clinical profiles of placenta accreta spectrum: the PACCRETA population-based study

OBJECTIVE

To describe and compare the characteristics of women with placenta accreta spectrum (PAS) and their pregnancy outcomes according to the presence of placenta praevia and a prior caesarean section.

DESIGN

Prospective population-based study.

SETTING

All 176 maternity hospitals of eight French regions.

POPULATION

Two hundred and forty-nine women with PAS, from a source population of 520 114 deliveries.

METHODS

Women with PAS were classified into two risk-profile groups, with or without the high-risk combination of placenta praevia (or an anterior low-lying placenta) and at least one prior caesarean. These two groups were described and compared.

MAIN OUTCOME MEASURES

Population-based incidence of PAS, characteristics of women, pregnancies, deliveries and pregnancy outcomes.

RESULTS

The PAS population-based incidence was 4.8/10 000 (95% CI 4.2-5.4/10 000). After exclusion of women lost to follow up from the analysis, the group with placenta praevia and a prior caesarean included 115 (48%) women and the group without this combination included 127 (52%). In the group with both factors, PAS was more often suspected antenatally (77% versus 17%; P < 0.001) and more often percreta (38% versus 5%; P < 0.001). This group also had more hysterectomies (53% versus 21%, P < 0.001) and higher rates of blood product transfusions, maternal complications, preterm births and neonatal intensive care unit admissions. Sensitivity analysis showed similar results after exclusion of women who delivered vaginally.

CONCLUSION

More than half the cases of PAS occurred in women without the combination of placenta praevia and a prior caesarean delivery, and these women had better maternal and neonatal outcomes. We cannot completely rule out that some of the women who delivered vaginally had placental retention rather than PAS; however, we found similar results among women who delivered by caesarean.

TWEETABLE ABSTRACT

Half the women with PAS do not have both placenta praevia and a prior caesarean delivery, and they have better maternal outcomes.

The impact of advanced maternal age on pregnancy and offspring health: A mechanistic role for placental angiogenic growth mediators

The birth rates among women of advanced maternal age (AMA) have risen over the last two decades; yet, pregnancies with AMA are considered high-risk and are associated with a significant increase in pregnancy complications. Although the mechanisms leading to pregnancy complications in women with AMA are not fully understood, it has been well established in the literature that offspring exposed to unfavorable environmental conditions in utero, such as gestational diabetes, preeclampsia, and/or intrauterine growth restriction during the early stages of development are subject to long-term health consequences. Additionally, angiogenic growth mediators, which drive vascular development of the placenta, are imbalanced in pregnancies with AMA. These same imbalances also occur in pregnancies complicated by preeclampsia, gestational diabetes, and obesity. This review discusses the impact of AMA on pregnancy and offspring health, and the potential mechanistic role of placental angiogenic growth mediators in the development of pregnancy complications at AMA.

Placentation in the Human and Higher Primates

Placentation in humans is precocious and highly invasive compared to other mammals. Implantation is interstitial, with the conceptus becoming completely embedded within the endometrium towards the end of the second week post-fertilization. Villi initially form over the entire surface of the chorionic sac, stimulated by histotrophic secretions from the endometrial glands. The secondary yolk sac never makes contact with the chorion, and a choriovitelline placenta is never established. However, recent morphological and transcriptomic analyses suggest that the yolk sac plays an important role in the uptake of nutrients from the coelomic fluid. Measurements performed in vivo demonstrate that early development takes place in a physiological, low-oxygen environment that protects against teratogenic free radicals and maintains stem cells in a multipotent state. The maternal arterial circulation to the placenta is only fully established around 10-12 weeks of gestation. By then, villi have regressed over the superficial, abembryonic pole, leaving the definitive discoid placenta, which is of the villous, hemochorial type. Remodeling of the maternal spiral arteries is essential to ensure a high-volume but low-velocity inflow into the mature placenta. Extravillous trophoblast cells migrate from anchoring villi and surround the arteries. Their interactions with maternal immune cells release cytokines and proteases that are key to remodeling, and a successful pregnancy.

Notch1 is crucial for decidualization and maintaining the first pregnancy in the mouse†

The endometrium undergoes a pregnancy-delivery-repair cycle multiple times during the reproductive lifespan in females. Decidualization is one of the critical events for the success of this essential process. We have previously reported that Notch1 is essential for artificial decidualization in mice. However, in a natural pregnancy, the deletion of Notch1 (PgrCre/+Notch1f/f, or Notch1d/d) only affects female fertility in the first 30 days of a 6-month fertility test, but not the later stages. In the present study, we undertook a closer evaluation at the first pregnancy of these mice to attempt to understand this puzzling phenomenon. We observed a large number of pregnancy losses in Notch1d/d mice in their first pregnancy, which led to the subfertility observed in the first 30 days of the fertility test. We then demonstrated that the initial pregnancy loss is a consequence of impaired decidualization. Furthermore, we identified a group of genes that contribute to Notch1 regulated decidualization in a natural pregnancy. Gene ontogeny analysis showed that these differentially expressed genes in the natural pregnancy are involved in cell-cell and cell-matrix interactions, different from genes that have been previously identified from the artificial decidualization model, which contribute to cell proliferation and apoptosis. In summary, we determined that Notch1 is essential for normal decidualization in the mouse uterus only in the first pregnancy but not in subsequent ones.

Insulin regulation of solute carrier family 2 member 1 (glucose transporter 1) expression and glucose uptake in decidualizing human endometrial stromal cells: an in vitro study

BACKGROUND

Solute carrier family 2 member 1 (SLC2A1; previously known as glucose transporter 1), is the most abundant glucose transporter in human endometrium and is up-regulated during decidualization, whereas high insulin may have a negative impact on this process. The present study aimed to investigate the effect of insulin on the expression of SLC2A1 and glucose uptake in decidualizing human endometrial stromal cells.

METHODS

We induced in vitro decidualization of endometrial stromal cells obtained from regularly menstruating healthy non-obese women. The cells were treated with increasing concentrations of insulin, and the involvement of the transcription factor forkhead box O1 (FOXO1) was evaluated using a FOXO1 inhibitor. SLC2A1 mRNA levels were measured by Real-Time PCR and protein levels were evaluated by immunocytochemistry. Glucose uptake was estimated by an assay quantifying the cellular uptake of radioactive glucose. One-way ANOVA, Dunnett's multiple comparisons test and paired t-test were used to determine the statistical significance of the results.

RESULTS

We found that insulin dose-dependently decreased SLC2A1 mRNA levels and decreased protein levels of SLC2A1 in decidualizing human endometrial stromal cells. Transcriptional inactivation of FOXO1 seems to explain at least partly the down-regulation of SLC2A1 by insulin. Glucose uptake increased upon decidualization, whereas insulin treatment resulted in a slight inhibition of the glucose uptake, although not significant for all insulin concentrations.

CONCLUSIONS

These results indicate an impairment of decidualization by high concentrations of insulin. Future studies will determine the clinical significance of our results for endometrial function and decidualization in women with insulin resistance and hyperinsulinemia.

Evidence for Corpus Luteal and Endometrial Origins of Adverse Pregnancy Outcomes in Women Conceiving with or Without Assisted Reproduction

Preeclampsia may arise from impaired decidualization in some women. Transcriptomics of mid-secretory biopsy endometrial stromal cells decidualized in vitro and of early gestation choriodecidua from women who experienced preeclampsia with severe features overlapped significantly with the classical endometrial disorders giving rise to the concept of "endometrium spectrum disorders". That is, recurrent implantation failure and miscarriage, endometriosis, normotensive intrauterine growth restriction, preeclampsia and preterm birth may all lie on a continuum of decidual dysregulation, in which phenotypic expression is determined by the specific molecular pathway(s) disrupted and severity of disruption. Women conceiving by programmed IVF protocols showed widespread dysregulation of cardiovascular function and increased rates of adverse pregnancy outcomes including preeclampsia. Programmed cycles preclude development of a corpus luteum (CL), a major regulator of endometrial function. Lack of circulating CL product(s) that are not replaced in programmed cycles (eg, relaxin) could adversely impact the maternal cardiovascular system directly and/or compromise decidualization, thereby increasing preeclampsia risk.

Platelet activation and placenta-mediated adverse pregnancy outcomes: an ancillary study to the Effects of Aspirin in Gestation and Reproduction trial

BACKGROUND

Platelet activation may play a role in the pathophysiology of placenta-mediated obstetrical complications, as evidenced by the efficacy of aspirin in preventing preeclampsia, but published data regarding the relationship between biomarkers for platelet activation and adverse obstetrical outcomes are sparse. In particular, it is unknown whether prepregnancy biomarkers of platelet activation are associated with adverse pregnancy outcomes.

OBJECTIVE

This study aimed to determine the following: (1) whether maternal plasma concentrations of platelet factor 4 are associated with risk of placenta-mediated adverse obstetrical outcomes, and (2) whether these associations are modified by low-dose aspirin.

STUDY DESIGN

This ancillary study included measurement of platelet factor 4 among 1185 of 1228 women of reproductive age enrolled in the Effects of Aspirin in Gestation and Reproduction trial with available plasma samples, with relevant outcomes assessed among 584 women with pregnancies lasting at least 20 weeks' gestation. We measured platelet factor 4 in plasma samples obtained at the prepregnancy study visit (before randomization to low-dose aspirin or placebo), 12 weeks' gestation, and 28 weeks' gestation. The primary outcome was a composite of hypertensive disorders of pregnancy, placental abruption, and small-for-gestational-age infant. We estimated the relative risks (RRs) and 95% confidence intervals (CIs) for the association between platelet factor 4 and the composite and individual outcomes at each time point using log-binomial regression that was weighted to account for potential selection bias and adjusted for age, body mass index, education, income, and smoking. To evaluate the potential effect modification of aspirin, we stratified the analyses by aspirin treatment assignment.

RESULTS

During follow-up, 95 women experienced the composite adverse obstetrical outcome, with 57 cases of hypertensive disorders of pregnancy, 35 of small for gestational age, and 6 of placental abruption. Overall, prepregnancy platelet factor 4 was positively associated with the composite outcome (third tertile vs first tertile; relative risk, 2.36; 95% confidence interval, 1.38-4.03) and with hypertensive disorders of pregnancy (third tertile vs first tertile; relative risk, 2.14; 95% confidence interval, 1.08-4.23). In analyses stratified by treatment group, associations were stronger in the placebo group (third tertile vs first tertile; relative risk, 3.36; 95% confidence interval, 1.42-7.93) than in the aspirin group (third tertile vs first tertile; relative risk, 1.78; 95% confidence interval, 0.90-3.50).

CONCLUSION

High concentrations of platelet factor 4 before pregnancy are associated with increased risk of placenta-mediated adverse pregnancy outcomes, particularly for hypertensive disorders of pregnancy. Aspirin may mitigate the increased risk of these outcomes among women with higher plasma concentrations of preconception platelet factor 4, but low-dose aspirin nonresponders may require higher doses of aspirin or alternate therapies to achieve obstetrical risk reduction.

The Role of Inflammation in the Pathogenesis of Preeclampsia

Preeclampsia (PE) affects 5-8% of pregnant women, and it is the major cause of perinatal morbidity and mortality. It is defined as arterial hypertension in women after 20 weeks of gestation which cooccurs with proteinuria (300 mg/d) or as arterial hypertension which is accompanied by one of the following: renal failure, liver dysfunction, hematological or neurological abnormalities, intrauterine growth restriction, or uteroplacental insufficiency. Currently, pathophysiology of preeclampsia poses a considerable challenge for perinatology. Preeclampsia is characterized by excessive and progressive activation of the immune system along with an increase in proinflammatory cytokines and antiangiogenic factors in fetoplacental unit as well as in vascular endothelium in pregnant women. A single, major underlying mechanism of preeclampsia is yet to be identified. This paper discusses the current understanding of the mechanisms which underlie the development of the condition. Some significant factors responsible for PE development include oxidative stress, abnormal concentration and activity in mononuclear phagocytic system, altered levels of angiogenic and antiangiogenic factors, and impaired inflammatory response triggered by inflammasomes. Detailed understanding of pathophysiology of inflammatory process in PE can largely contribute to new, targeted anti-inflammatory therapies that may improve perinatal outcomes in PE patients.

Impact of chronic endometritis on endometrial receptivity analysis results and pregnancy outcomes

BACKGROUND

The aim of this study is to evaluate the relationship between chronic endometritis (CE) and a personalized window of implantation (WOI), identified by results of endometrial receptivity analysis (ERA), and pregnancy outcomes following embryo transfer (ET) based on the ERA outcomes.

METHODS

The single-center, cross-sectional study was designed. The study population consisted of 101 infertile women who underwent endometrial sampling between June 2018 and February 2020. We recruited 88 patients who underwent ERA testing and immunohistochemistry of the plasma cell marker CD138 to diagnose CE within 3 months of testing. Subjects were divided into three groups as follows: 33 without CE (non-CE group); 19 with untreated CE at ERA testing (CE group); and 36 successfully treated for CE before ERA testing (cured-CE group). CE diagnosis was defined as ≥5 CD138-positive plasma cells per 10 random stromal areas at ×400 magnification.

RESULTS

In non-CE, CE, and cured-CE groups, the numbers of CD138-positive cells were 0.7 ± 1.0, 28.5 ± 30.4, and 1.3 ± 1.3, respectively (p < .001). The rates of "receptive" endometrium in non-CE and cured-CE groups were 57.6% (19 women) and 50.0% (18 women), respectively; however, in the CE group, this rate was significantly lower than the other two groups (p = .009) at only 15.8% (3 women). After CE were treated prior or posterior to the ERA test in cured-CE or CE groups, the clinical pregnancy rates at the first ET in non-CE, CE, and cured-CE groups were 77.8% (21/27 cycles), 22.2% (4/18 cycles), and 51.7% (15/29 cycles), respectively (p < 0.001).

CONCLUSION

CE had detrimental effects on the individual WOI, leading to embryo-endometrial asynchrony; therefore, diagnosis and treatment of CE should be done before ERA testing.

Maternal Obesity Does Not Exacerbate the Effects of LPS Injection on Pregnancy Outcomes in Mice

Obesity increases the risk of a number of pregnancy complications, potentially due to chronic inflammation. We predicted that an obesogenic high-fat diet (HFD) in mice would create an inflammatory environment that would exacerbate the effects of lipopolysaccharide (LPS), an inflammatory insult, administered during pregnancy. Females were placed on a HFD or a low-fat diet (LFD) prior to mating, injected with 2 µg LPS or control on gestational day 7 and collected on day 14. Treatment with LPS increased the odds that a female thought to be pregnant at injection had no conceptuses at day 14 (p = 0.024), suggesting that injection with LPS was more likely to induce complete abortion. However, there was no effect of diet on the odds of having no conceptuses at day 14 and no interaction between diet and LPS injection. Diet and LPS injection had no effect on the number of viable fetuses in females still pregnant at day 14. For fetal weight, there was a significant interaction between diet and treatment (p = 0.017), whereby LPS reduced fetal weight in HFD females but not in LFD females. However, LPS treatment of HFD females reduced fetal weight to that observed in control-injected LFD females. Although LPS increased the odds of abortion, there was little evidence that a HFD exacerbated the effects of LPS.

Placenta accrete after a frozen-thawed embryo transfer in a systemic lupus erythematosus patient treated with hydroxychloroquine

Placenta accreta (PA) is a life-threatening disorder associated with decidual maldevelopment and a thin endometrium. Few cases of systemic lupus erythematosus (SLE) pregnancy complicated by PA have been reported, and the background pathophysiology remains elusive. Here, we report a case of PA in SLE pregnancy treated with hydroxychloroquine. A nulligravida woman with SLE, aged 41 years, visited our hospital because of infertility problems. Her SLE was treated with prednisolone and tacrolimus. We conducted assisted reproductive technology and gained several embryos. An artificial cycle successfully prepared the endometrium for embryo transfer with sufficient thickness. Over time, her SLE exacerbated, and we started hydroxychloroquine administration. Consequently, the endometrium did not respond to hormonal supplementation and remained thin, but we transferred the embryo and managed to achieve pregnancy. On the 38th week of gestation, we conducted labor induction because of elevated blood pressure. Induction was not effective, so we performed cesarean section; PA was observed. We performed compression suturing and were able to stop the hemorrhage. Postoperative uterine infarction and pelvic infection were successfully managed with conservative treatment. The present case highlights the use of hydroxychloroquine during endometrial development and contributes evidence regarding the pathogenesis of PA in pregnancy complicated by SLE.

Aldosterone from endometrial glands is benefit for human decidualization

Local renin-angiotensin system (RAS) in female reproductive system is involved in many physiological and pathological processes, such as follicular development, ovarian angiogenesis, ovarian, and endometrial cancer progress. However, studies on the functional relevance of RAS in human endometrium are limited, especially for renin-angiotensin-aldosterone system (RAAS). In this study, we defined the location of RAS components in human endometrium. We found that angiotensin II type-1 receptor (AT₁R) and aldosterone synthase (CYP11B2), major components of RAAS, are specifically expressed in endometrial gland during mid-secretory phase. Aldosterone receptor, mineralocorticoid receptor (MR), is elevated in stroma in mid-secretory endometrium. In vitro, MR is also activated by aldosterone during decidualization. Activated MR initiates LKB1 expression, followed by phosphorylating of AMPK that stimulates PDK4 expression. The impact of PDK4 on decidualization is independent on PDHE1α inactivation. Based on co-immunoprecipitation, PDK4 interacts with p-CREB to prevent its ubiquitination for facilitating decidualization via FOXO1. Restrain of MR activation interrupts LKB1/p-AMPK/PDK4/p-CREB/FOXO1 pathway induced by aldosterone, indicating that aldosterone action on decidualization is mainly dependent on MR stimulation. Aldosterone biosynthesized in endometrial gland during mid-secretory phase promotes decidualization via activating MR/LKB1/p-AMPK/PDK4/p-CREB/FOXO1 signaling pathway. This study provides the valuable information for understanding the underlying mechanism during decidualization.

Tryptophan and kynurenine stimulate human decidualization via activating Aryl hydrocarbon receptor: Short title: Kynurenine action on human decidualization

Decidualization is essential for successful pregnancy in rodents and primates. Although L-Tryptophan and its metabolites are essential for mammalian pregnancy, the underlying mechanism is poorly defined. We explored effects of tryptophan and kynurenine on human in vitro decidualization in human endometrial stromal cell line and primary endometrial stromal cells. Tryptophan significantly stimulates the expression of prolactin and insulin growth factor binding protein 1, reliable markers for human decidualization. When stromal cells are treated with tryptophan, tryptophan hydroxylase-1 remains unchanged, but indoleamine 2,3-dioxygenase 1 is significantly increased, suggesting tryptophan is mainly metabolized through kynurenine pathway. Kynurenine significantly stimulates insulin growth factor binding protein 1 expression. Aryl hydrocarbon receptor and its target genes (P450 1A1 and P450 1B1) are significantly increased by tryptophan and kynurenine. The induction of tryptophan and kynurenine on insulin growth factor binding protein 1 is abrogated by CH223191, an aryl hydrocarbon receptor inhibitor. Cytochrome P450 1A1 and P450 1B1 catalyze the oxidative metabolism of estradiol to catechol estrogens (2-hydroxy estradiol and 4-hydroxy estradiol), respectively. Insulin growth factor binding protein 1 is up-regulated by 2-hydroxy estradiol and 4-hydroxy estradiol. Interferon-γ significantly induces the expression of indoleamine 2,3-dioxygenase 1, aryl hydrocarbon receptor and insulin growth factor binding protein 1. All the data are also verified in primary human stromal cells. Our data indicate that Interferon-γ-induced kynurenine pathway promotes human decidualization via aryl hydrocarbon receptor signaling.

Endometrial receptivity and pregnancy outcome

Human implantation is a highly complex and multifactorial process. Successful implantation requires the presence of a healthy embryo, a receptive endometrium, and a synchronized molecular dialogue between the two, as well as immune tolerance/protection from the host. The endometrial receptivity refers to a hormonally limited period in which the endometrial tissue acquires a transient functional status allowing blastocyst implantation and pregnancy initiation. Global knowledge of endometrial receptivity grew up in recent years. Improvements in genetics, new biomarkers, noninvasive methods, new advanced techniques (Endometrial receptivity assay - the ERA system, proteomic analysis) offer the possibility to evaluate the endometrial status and to manage patients with infertility problems, especially women undergoing assisted reproductive treatment. This overview reports the most relevant knowledge and recent advances in the study of implantation processes from the perspective of the endometrium, often considered as being the main barrier for a successful pregnancy initiation. Endometrial receptivity is a topic of great interest and further studies are needed for the early identification of endometrial abnormalities and the discovery of new strategies for increasing the chance for the establishment of pregnancy.

Association of lncRNA SH3PXD2A-AS1 with preeclampsia and its function in invasion and migration of placental trophoblast cells

Accumulating evidence suggests that the pathogenesis of preeclampsia involves poor placentation caused by insufficient trophoblast invasion and impaired uterine spiral artery remodeling, yet the underlying molecular mechanism remains unclear. We carried out transcriptome profiling on placentae from preeclamptic patients and normal subjects, and identified about four hundred long non-coding RNAs differentially expressed in placentae of patients with early-onset severe preeclampsia. Here, we report our identification of lncRNA SH3PXD2A-AS1 as a potential causal factor for this disease and its downstream pathways involved in placentation. We found that expression level of SH3PXD2A-AS1 in the placentae is positively correlated with clinical severity of the patients. We demonstrated that SH3PXD2A-AS1 inhibited invasion and migration through recruiting CCCTC-binding factor (CTCF) to the promoters of SH3PXD2A and CCR7 to inhibit their transcription. Therefore, we conclude that the upregulation of lncRNA SH3PXD2A-AS1 may contribute to the pathogenesis of preeclampsia through prohibiting trophoblast invasion during placentation.

Transcription factor AP2A affects sFLT1 expression and decidualization in decidual stromal cells: Implications to preeclampsia pathology

Preeclampsia (PE) yields a spectrum of phenotypic expression, leading to varying degrees of hypertension, maternal renal dysfunction and placental insufficiency with resultant maternal and neonatal morbidity. Increased sFLT1 expression contributing to angiogenic factor imbalance, placental hypoxia, failed immune adaptation to the fetus and defective decidualization are among the commonly proposed theories of PE pathogenesis. Recently researchers have focused their attention on the events that occur at the maternal fetal interface as potential contributors to PE pathogenesis. Decidual stromal cells (DSC) isolated from preeclamptic women show diminished ability to decidualize upon stimulation and reduced capacity to downregulate sFlt-1 levels. In this study, we sought to gain insight into the molecular mechanism(s) involved in the aberrant decidualization capacity of PE DSC. Our findings using qRT-PCR show that PE DSCs have 6-fold higher basal levels of transcription factor AP2A (TFAP2A) RNA compared to women without PE and that expression of TFAP2A increases during decidualization but only in DSCs of normotensive (NT) women. Silencing of TFAP2A using Trilencer siRNA upregulated sFLT1 expression only in NT-DSCs but suppressed the expression of decidualization markers PRL, IGFBP1 and their regulator FOXO1 in cells from both groups. Collectively, our observations suggest that TFAP2A acts as a repressor of sFLT1 and plays a necessary role in decidualization possibly through interacting with another factor that is aberrantly expressed in PE DSCs.

Organoid systems to study the human female reproductive tract and pregnancy

Both the proper functioning of the female reproductive tract (FRT) and normal placental development are essential for women’s health, wellbeing, and pregnancy outcome. The study of the FRT in humans has been challenging due to limitations in the in vitro and in vivo tools available. Recent developments in 3D organoid technology that model the different regions of the FRT include organoids of the ovaries, fallopian tubes, endometrium and cervix, as well as placental trophoblast. These models are opening up new avenues to investigate the normal biology and pathology of the FRT. In this review, we discuss the advances, potential, and limitations of organoid cultures of the human FRT.

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Is advanced maternal age associated with placental vascular malperfusion? A prospective study from a single tertiary center

PURPOSE

Pregnancy at advanced maternal age (AMA) has become more common. There has been concern regarding the adverse effect deferring pregnancy might have on pregnancy outcomes. We aimed to prospectively study the effect of AMA on placental pathology.

METHODS

A prospective case-control study was performed in a single university center. Placental histopathology, maternal demographics, labor characteristics, and neonatal outcomes of pregnancies with AMA were collected and compared to matched controls. We defined AMA as maternal age > 35 years at delivery. In attempt to isolate the effect of maternal age, we excluded cases complicated by preterm birth, hypertensive disorders, diabetes mellitus, small for gestational age, and congenital/genetic anomalies.

RESULTS

The study group included 110 AMA patients that were matched with controls. The groups did not differ in maternal demographics, but the AMA group had a higher rate of assisted reproductive technologies (ART) as compared to the control group (p < 0.001). Placentas in the AMA group were characterized by a higher rate of maternal vascular lesions (MVM) (39.1% vs. 24.5%, p = 0.003), but not fetal vascular malperfusion lesions (p = 0.576). In multivariable analysis maternal age was associated with placental MVM lesions independent of all other maternal demographics (aOR 1.18 95% CI 1.06-3.17). Neonatal outcomes did not significantly differ between the groups.

CONCLUSIONS

After excluding all background morbidities-AMA was associated with a higher rate of placental MVM lesions vs. controls. These findings suggest an independent effect of AMA on placental function. Large prospective trials are needed to study the clinical importance of these findings.

Perfluoroalkyl substances in early pregnancy and risk of hypertensive disorders of pregnancy: A prospective cohort study

BACKGROUND

Perfluoroalkyl substances (PFASs) were reported to be associated with hypertensive disorders of pregnancy (HDP) but the results were inconsistent and prospective data are scarce. We aimed to examine these associations in a large prospective birth cohort study in Shanghai, China.

METHODS

A total of 10 PFASs were measured by high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS-MS) in the plasma samples from 3220 women who were enrolled during early pregnancy and gave birth to a singleton live birth between 2013 and 2016. The outcomes included gestational hypertension (GH), preeclampsia (PE) and overall HDP. Associations of these outcomes with each PFASs were estimated by multivariable logistic regression and expressed as odd ratios (ORs) and 95% confidence intervals (95% CIs). Potential non-linear association between PFASs and HDP was examined with restricted cubic spline model. To handle the potential confounding by correlated PFASs, we applied elastic net regression (ENR) to identify independent PFASs components of outcomes.

RESULTS

Among all singleton live births, the incidence rates of GH and PE were 2.0% and 2.2%, respectively. Overall, PFASs did not show a significant and consistent pattern of the associations with GH, PE or overall HDP, both before and after controlling for potential confounders. ENR model confirmed the results that there was no independently predictive role of PFASs on GH, PE or overall HDP.

CONCLUSIONS

In this large prospective cohort study, maternal plasma concentration of PFASs in early pregnancy were not associated with GH, PE or overall HDP in singleton livebirths.

Transcription factor ID1 is involved in decidualization of stromal cells: Implications in preeclampsia

Decidual stromal cells (DSC) from women with preeclampsia (PE) show defective decidualization upon in vitro treatment with cAMP. Decidualization is associated with a multitude of gene expression changes and is a prerequisite for embryo implantation. We reason that the process of decidualization involves a cascade of changes in transcriptional regulators. Our prior studies have found defective decidualization of PE-DSCs as reflected by low prolactin (PRL) levels and other decidualization markers. Transcription factor array analysis identified inhibitor of DNA binding (ID1) and FOXO1 as top differentially expressed genes during decidualization. Unlike ID1, FOXO1 involvement in decidualization has been established. We hypothesized that ID1 plays a major role in regulating stromal cell decidualization. Our data shows basal ID1 mRNA expression is significantly higher in PE DSCs. Cyclic AMP-mediated decidualization significantly upregulates ID1 mRNA expression in DSCs and siRNA-mediated knockdown of ID1 significantly interferes with decidualization as shown by a reduction in PRL and FOXO1 expression, and morphologic criteria. Thus ID1 may serve as a master regulator of stromal cell differentiation and defects in ID1 expression may affect decidualization as seen in PE-DSCs.

Artificial intelligence-assisted prediction of preeclampsia: Development and external validation of a nationwide health insurance dataset of the BPJS Kesehatan in Indonesia

Background

We developed and validated an artificial intelligence (AI)-assisted prediction of preeclampsia applied to a nationwide health insurance dataset in Indonesia.

Methods

The BPJS Kesehatan dataset have been preprocessed using a nested case-control design into preeclampsia/eclampsia (n = 3318) and normotensive pregnant women (n = 19,883) from all women with one pregnancy. The dataset provided 95 features consisting of demographic variables and medical histories started from 24 months to event and ended by delivery as the event. Six algorithms were compared by area under the receiver operating characteristics curve (AUROC) with a subgroup analysis by time to the event. We compared our model to similar prediction models from systematically reviewed studies. In addition, we conducted a text mining analysis based on natural language processing techniques to interpret our modeling results.

Findings

The best model consisted of 17 predictors extracted by a random forest algorithm. Nine∼12 months to the event was the period that had the best AUROC in external validation by either geographical (0.88, 95% confidence interval (CI) 0.88–0.89) or temporal split (0.86, 95% CI 0.85–0.86). We compared this model to prediction models in seven studies from 869 records in PUBMED, EMBASE, and SCOPUS. This model outperformed the previous models in terms of the precision, sensitivity, and specificity in all validation sets.

Interpretation

Our low-cost model improved preliminary prediction to decide pregnant women that will be predicted by the models with high specificity and advanced predictors.

Funding

This work was supported by grant no. MOST108-2221-E-038-018 from the Ministry of Science and Technology of Taiwan.

Human Endometrial Transcriptome and Progesterone Receptor Cistrome Reveal Important Pathways and Epithelial Regulators

CONTEXT

Poor uterine receptivity is one major factor leading to pregnancy loss and infertility. Understanding the molecular events governing successful implantation is hence critical in combating infertility.

OBJECTIVE

To define Progesterone Receptor (PGR)-regulated molecular mechanisms and epithelial roles in receptivity.

DESIGN

RNA-sequencing and PGR-ChIP-seq were conducted in parallel to identify PGR-regulated pathways during the Window of implantation (WOI) in endometrium of fertile women.

SETTING

Endometrial biopsies from the proliferative and mid-secretory phases were analyzed.

PATIENTS OR OTHER PARTICIPANTS

Participants were fertile, reproductive aged (18-37 years) women with normal cycle length, and without any history of dysmenorrhea, infertility, or irregular cycles. In total, 42 endometrial biopsies obtained from 42 women were analyzed in this study.

INTERVENTIONS

There were no interventions during this study.

MAIN OUTCOME MEASURES

Here we measured the alterations in gene expression and PGR occupancy in the genome during the WOI, based on the hypothesis that PGR binds uterine chromatin cycle dependently to regulate genes involved in uterine cell differentiation and function.

RESULTS

653 genes were identified with regulated PGR binding and differential expression during the WOI. These were involved in regulating inflammatory response, xenobiotic metabolism, epithelial mesenchymal transition, cell death, interleukin/Signal Transducer And Activator Of Transcription (STAT) signaling, estrogen response, and Mammalian target of rapamycin complex 1 (MTORC1) response. Transcriptome of the epithelium identified 3052 differentially expressed genes, of which 658 were uniquely regulated. Transcription factors Interferon Regulatory Factor 8 (IRF8) and Myocyte Enhancer Factor 2C (MEF2C) were found to be regulated in the epithelium during the WOI at the protein level, suggesting potentially important functions that are previously unrecognized.

CONCLUSION

PGR binds the genomic regions of genes regulating critical processes in uterine receptivity and function.

Preeclampsia: a defect in decidualization is associated with deficiency of Annexin A2

BACKGROUND

Decidualization defects in the endometrium have been demonstrated at the time of delivery in women with severe preeclampsia and to linger for years, which suggests a maternal contribution to the pathogenesis of this condition. Global transcriptional profiling reveals alterations in gene expression, which includes down-regulation of Annexin A2 in severe preeclampsia patients with decidualization resistance.

OBJECTIVE

We investigated the functional role of Annexin A2 deficiency during endometrial decidualization and its potential contribution to shallow trophoblast invasion during implantation and subsequent placentation using in vitro and in vivo modeling.

STUDY DESIGN

Annexin A2 gene and protein levels were assessed during in vitro decidualization of human endometrial stromal cells isolated from biopsy specimens that were collected from women with previous severe preeclampsia (n=5) or normal obstetric outcomes (n=5). Next, Annexin A2 was inhibited with small interference RNA in control human endometrial stromal cells that were isolated from endometrial biopsy specimens (n=15) as an in vitro model to analyze decidualization defects at the morphologic level and the secretion of prolactin and insulin-like growth binding protein-1. Annexin A2-inhibited cells were used to evaluate motility and promotion of embryo invasion. Decidualization and placentation defects of Annexin A2 deficiency were confirmed with the use of an Annexin A2-null mouse model.

RESULTS

Annexin A2 gene and protein levels were down-regulated during in vitro decidualization of human endometrial stromal cells from women with previous severe preeclampsia compared with control individuals. To assess its role in the endometrial stroma, we inhibited Annexin A2 expression and detected decidualization failure as evidenced by impaired morphologic transformation, which was associated with altered actin polymerization and low prolactin and insulin-like growth binding protein-1 secretions. Functionally, in vitro models demonstrated that Annexin A2 inhibition failed to support embryo invasion. This finding was corroborated by reduced trophoblast spreading through human endometrial stromal cells, lack of motility of these cells, and reduced trophoblast invasion in the presence of conditioned media from Annexin A2-inhibited cells. Extending our discovery to an animal model, we detected that Annexin A2-null mice have a functional deficiency in decidualization and placentation that impairs fetal growth as a feature that is associated with severe preeclampsia.

CONCLUSION

Together, in vitro and in vivo results suggest that endometrial defects in Annexin A2 expression impair decidualization of endometrial stromal cells as well as the uterine microenvironment that promotes embryo implantation and placentation. Our findings highlight the maternal contribution to the pathogenesis of severe preeclampsia and suggest that evaluation of Annexin A2 may provide a novel strategy to assess a woman's risk of experiencing this disease and perhaps discover therapeutic interventions to improve decidualization.

Maternal and perinatal outcomes in programmed versus natural vitrified-warmed blastocyst transfer cycles

RESEARCH QUESTION

Do maternal and perinatal outcomes differ between natural and programmed frozen embryo transfer (FET) cycles?

DESIGN

Retrospective cohort study at a university-affiliated fertility centre including 775 patients who underwent programmed or natural FET cycles resulting in a singleton live birth using blastocysts vitrified between 2013 and 2018.

RESULTS

A total of 384 natural and 391 programmed FET singleton pregnancies were analysed. Programmed FET resulted in higher overall maternal complications (32.2% [126/391] versus 18.8% [72/384]; P < 0.01), including higher probability of hypertensive disorders of pregnancy (HDP) (15.3% [60/391] versus 6.3% [24/384]; P < 0.01), preterm premature rupture of membranes (2.6% [10/391] versus 0.3% [1/384]; P = 0.02) and caesarean delivery (53.2% [206/387] versus 42.8% [163/381]; P = 0.03) compared with natural FET. After controlling for potential confounders, including age, body mass index, parity, smoking status, history of diabetes or chronic hypertension, infertility diagnosis, number of embryos transferred and use of preimplantation genetic testing, the adjusted odds ratio for HDP was 2.39 (95% CI 1.37 to 4.17) and for overall maternal complications was 2.21 (95% CI 1.51 to 3.22) comparing programmed with natural FET groups. The groups did not significantly differ for any perinatal outcomes analysed, including birth weight (3357.9 ± 671.6 g versus 3318.4 ± 616.2 g; P = 0.40) or rate of birth defects (1.5% [6/391] versus 2.1% [8/384]; P = 0.57), respectively.

CONCLUSION

Vitrified-warmed blastocyst transfer in a programmed cycle resulted in a twofold higher probability of HDP compared with transfer in a natural cycle. Natural FET cycle should, therefore, be recommended as first line for all eligible patients undergoing FET to reduce the risk of HDP.

Hippo-YAP1 signaling pathway and severe preeclampsia (sPE) in the Chinese population

BACKGROUND

The present study aims to explore the possible mechanisms of Hippo-YAP1 signaling pathway in the development of severe preeclampsia (sPE).

METHODS

A total of 14 pregnancies complicated with severe preeclampsia as well as 14 healthy pregnancies were involved in this research from Department of Obstetrics, the First Affiliated Hospital of Xi'An Jiaotong University, from 15th March 2016 to 15th March 2018. The mRNA levels of YAP1, TAZ, MST1 and MST2 were tested via the RT-qPCR in the placentas between the two groups. Also, the protein expression degrees of YAP1, TAZ, MST 1 and MST 2 were detected using the technology of Western blotting. At the same time, immune-histochemistry method was performed to localize the expression of YAP1, TAZ, MST 1 and MST 2 proteins in the placentas between the two groups. Yes-associated protein expression was also detected in BeWo and HTR-8/SVneo. Overexpressed plasmid and YAP1 si-RNA were transfered into HTR-8/SVneo trophoblast cells. Transwell invasion assay was used to examine the role of YAP1 in the invasion of HTR-8/SVneo trophoblast cells.

RESULTS

In comparison with the normal pregnancy placentas, the mRNA levels of YAP (0.659 ± 0.169 vs. 1.758 ± 0.587, P < 0.001) and TAZ (1.148 ± 0.313 vs. 2.894 ± 0.470, P < 0.001) were decreased in the placentas of severe preeclampsia group while the mRNA levels of MST 1 (1.433 ± 0.306 vs. 0.663 ± 0.162, P < 0.001) and MST 2 (1.497 ± 0.378 vs. 0.554 ± 0.130, P < 0.001) were increased. The Western blotting shown that the expression degrees of YAP1 and TAZ proteins were significantly decreased in the placentas of severe preeclampsia, while the expression level of MST 1 and MST 2 was obviously increased. Furthermore, the staining intensity of YAP1 and TAZ were weaker in the placentas of the severe PE group while the staining intensity of MST 1 and MST 2 was significantly stronger in the placentas of the severe PE group. The invasion ability of the HTR-8/SVneo cells in the YAP1-overexpressed group was significantly higher than the corresponding control group ((313.7 ± 5.86) vs.(194.0 ± 4.00), P < 0.05) while the si-YAP1 group was significantly lower than that of the corresponding control group ((81.33 ± 2.52) vs. (204.67 ± 11.02), P < 0.05).

CONCLUSIONS

Hippo-YAP1 signaling pathway may play an essential role in the pathogenesis of sPE by regulating the invasion and proliferation of trophoblast.

In vitro fertilization add-ons for the endometrium: it doesn't add-up

The probability of live birth from an in vitro fertilization (IVF) cycle is modest. Many additional treatments (add-ons) are available which promise to improve the success of IVF. This review summarizes the current evidence for common IVF add-ons which are suggested to improve endometrial receptivity. Systematic reviews of randomized controlled trials and individual trials were included. Five add-ons were included: immune therapies, endometrial scratching, endometrial receptivity array, uterine artery vasodilation, and human chorionic gonadotropin instillation. The results suggest there is no robust evidence that these add-ons are effective or safe. Many IVF add-ons are costly, consuming precious resources which may be better spent on evidence-based treatments or further IVF. Large randomized controlled trials and appropriate safety assessment should be mandatory before the introduction of IVF add-ons into routine practice.

Development of the human placenta

The placenta is essential for normal in utero development in mammals. In humans, defective placental formation underpins common pregnancy disorders such as pre-eclampsia and fetal growth restriction. The great variation in placental types across mammals means that animal models have been of limited use in understanding human placental development. However, new tools for studying human placental development, including 3D organoids, stem cell culture systems and single cell RNA sequencing, have brought new insights into this field. Here, we review the morphological, molecular and functional aspects of human placental formation, with a focus on the defining cell of the placenta - the trophoblast.

Retinoic Acid Is a Negative Regulator of sFLT1 Expression in Decidual Stromal Cells, and Its Levels Are Reduced in Preeclamptic Decidua

sFLT1 (soluble VEGF [vascular endothelial growth factor] receptor-1) levels are increased in preeclampsia-a pathological condition of pregnancy. The mechanism of sFLT1 overexpression by gestational tissues, particularly the decidua, remains unknown. Mass spectrometry measurement of the active retinoid metabolite, all-trans retinoic acid (RA), showed significantly lower levels of RA in preeclamptic versus normotensive decidua. In this study, we investigated the involvement of RA in regulating decidual sFLT1 expression. When decidual stromal cells (DSCs) isolated from the decidua basalis of normotensive and preeclampsia placentas were treated with BMS493-a pan-RAR (RA nuclear receptor) antagonist-upregulation of sFLT1 expression was observed. Conversely, treatment with RA resulted in downregulation of sFLT1 in normotensive DSCs and preeclampsia DSCs. Unlike treatment with cAMP, which induces decidualization while downregulating sFLT1, RA treatment did not alter DSC expression of prolactin-a marker of decidualization-or FOXO1 (forkhead box protein 01)-a transcription factor required for prolactin upregulation. TFAP2A (transcription factor AP-2-alpha [activating enhancer-binding protein 2 alpha]), a different transcription factor was upregulated in normotensive DSCs but not in preeclampsia DSCs after RA treatment. Collectively, our data show that RA suppresses sFLT1 expression in DSCs independently of cellular decidualization. These findings suggest that reduced decidual RA levels may contribute to preeclampsia pathogenesis by allowing sFLT1 accumulation at the maternal-fetal interface.

Evidence for shared molecular pathways of dysregulated decidualization in preeclampsia and endometrial disorders revealed by microarray data integration

Microarray data of chorionic villous samples (CVSs) obtained from women of ∼11.5 gestational weeks who developed preeclampsia with severe features (sPE; PE-CVS) revealed a molecular signature of impaired endometrial maturation (decidualization) before and during early pregnancy. Because endometrial disorders are also associated with aberrant decidualization, we asked whether they share molecular features with sPE. We employed microarray data integration to compare the molecular pathologies of PE-CVS and endometrial disorders, as well as decidua obtained postpartum from women with sPE. Eight public databases were reanalyzed with R software to determine differentially expressed genes (DEGs) in pathologic tissues relative to normal controls. DEGs were then compared to explore overlap. Shared DEGs were examined for enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Principal component and network analyses were subsequently applied to selected DEGs. There was significant overlap of DEGs changing in the same direction for PE-CVS and endometrial disorders, suggesting common molecular pathways. Shared DEGs were enriched for cytokine-cytokine receptor interaction. Genes in this pathway revealed expression patterns forming 2 distinct clusters, one for normal and the other pathologic endometrium. The most affected hub genes were related to decidualization and NK cell function. Few DEGs were shared by PE-CVS, and PE decidua obtained postpartum. sPE may be part of a biologic continuum of "endometrial spectrum disorders."-Rabaglino, M. B., Conrad, K. P. Evidence for shared molecular pathways of dysregulated decidualization in preeclampsia and endometrial disorders revealed by microarray data integration.

Role of the Monocyte-Macrophage System in Normal Pregnancy and Preeclampsia

The proper functioning of the monocyte-macrophage system, an important unit of innate immunity, ensures the normal course of pregnancy. In this review, we present the current data on the origin of the monocyte-macrophage system and its functioning in the female reproductive system during the ovarian cycle, and over the course of both normal and complicated pregnancy. Preeclampsia is a crucial gestation disorder characterized by pronounced inflammation in the maternal body that affects the work of the monocyte-macrophage system. The effects of inflammation at preeclampsia manifest in changes in monocyte counts and their subset composition, and changes in placental macrophage counts and their polarization. Here we summarize the recent data on this issue for both the maternal organism and the fetus. The influence of estrogen on macrophages and their altered levels in preeclampsia are also discussed.

Hemochorial placentation: development, function, and adaptations

Placentation is a reproductive adaptation that permits fetal growth and development within the protected confines of the female reproductive tract. Through this important role, the placenta also determines postnatal health and susceptibility to disease. The hemochorial placenta is a prominent feature in primate and rodent development. This manuscript provides an overview of the basics of hemochorial placental development and function, provides perspectives on major discoveries that have shaped placental research, and thoughts on strategies for future investigation.

Pre-eclampsia: pathophysiology and clinical implications

Pre-eclampsia is a common disorder that particularly affects first pregnancies. The clinical presentation is highly variable but hypertension and proteinuria are usually seen. These systemic signs arise from soluble factors released from the placenta as a result of a response to stress of syncytiotrophoblast. There are two sub-types: early and late onset pre-eclampsia, with others almost certainly yet to be identified. Early onset pre-eclampsia arises owing to defective placentation, whilst late onset pre-eclampsia may center around interactions between normal senescence of the placenta and a maternal genetic predisposition to cardiovascular and metabolic disease. The causes, placental and maternal, vary among individuals. Recent research has focused on placental-uterine interactions in early pregnancy. The aim now is to translate these findings into new ways to predict, prevent, and treat pre-eclampsia.

Giants in Obstetrics and Gynecology Series: A profile of James M. Roberts, MD

Dr. James Roberts has made seminal contributions to the understanding of the physiology of pregnancy, and, in particular, to the mechanisms of disease responsible for preeclampsia. His research includes endothelial cell dysfunction, oxidative stress, and other factors that play a role in the pathogenesis of preeclampsia; the use of antioxidant therapy to prevent the syndrome; identification of clinical subtypes of preeclampsia; and assessment of the long-term cardiovascular risk of the disorder. Dr. Roberts is currently an investigator at the Magee-Womens Research Institute and a Professor of Obstetrics, Gynecology, and Reproductive Sciences, Endocrinology, and Clinical and Translational Medicine at the University of Pittsburgh. He was the founding Director of the Magee-Womens Research Institute, and formerly the Elsie Hilliard Hillman Chair in Women’s and Infants’ Health Research at the University of Pittsburgh. For his many original contributions to the understanding of preeclampsia and other obstetrical syndromes, Dr. Roberts is herein recognized as a “Giant in Obstetrics and Gynecology.”

Integrative analysis of the forkhead box A2 (FOXA2) cistrome for the human endometrium

The pioneer forkhead box (FOX)A2 transcription factor is specifically expressed in the glands of the uterus, which are central to endometrial function and fertility. In mice, FOXA2 is a critical regulator of uterine gland development in the neonate and gland function in the adult. An integrative approach was used here to define the FOXA2 cistrome in the human endometrium. Genome-wide mapping of FOXA2 binding intervals by chromatin immunoprecipitation sequencing was performed using proliferative (P)- and midsecretory (MS)-phase endometrium and integrated with the transcriptome determined by RNA sequencing. Distinctive FOXA2 binding intervals, enriched for different transcription factor binding site motifs, were detected in the P and MS endometrium. Pathway analysis revealed different biologic processes regulated by genes with FOXA2 binding intervals in the P and MS endometrium. Thus, FOXA2 is postulated to regulate gene expression in concert with other transcription factors and impact uterine gland development and function in a cycle phase-dependent manner. Analyses also identified potential FOXA2-regulated genes that influence uterine receptivity, blastocyst implantation, and stromal cell decidualization, which are key events in pregnancy establishment.-Kelleher, A. M., Behura, S. K., Burns, G. W., Young, S. L., DeMayo, F. J., Spencer, T. E. Integrative analysis of the forkhead box A2 (FOXA2) cistrome for the human endometrium.

How uterine microbiota might be responsible for a receptive, fertile endometrium

BACKGROUND

Fertility depends on a receptive state of the endometrium, influenced by hormonal and anatomical adaptations, as well as the immune system. Local and systemic immunity is greatly influenced by microbiota. Recent discoveries of 16S rRNA in the endometrium and the ability to detect low-biomass microbiota fueled the notion that the uterus may be indeed a non-sterile compartment. To date, the concept of the 'sterile womb' focuses on in utero effects of microbiota on offspring and neonatal immunity. However, little awareness has been raised regarding the importance of uterine microbiota for endometrial physiology in reproductive health; manifested in fertility and placentation.

OBJECTIVE AND RATIONALE

Commensal colonization of the uterus has been widely discussed in the literature. The objective of this review is to outline the possible importance of this uterine colonization for a healthy, fertile uterus. We present the available evidence regarding uterine microbiota, focusing on recent findings based on 16S rRNA, and depict the possible importance of uterine colonization for a receptive endometrium. We highlight a possible role of uterine microbiota for host immunity and tissue adaptation, as well as conferring protection against pathogens. Based on knowledge of the interaction of the mucosal immune cells of the gut with the local microbiome, we want to investigate the potential implications of commensal colonization for uterine health.

SEARCH METHODS

PubMed and Google Scholar were searched for articles in English indexed from 1 January 2008 to 1 March 2018 for '16S rRNA', 'uterus' and related search terms to assess available evidence on uterine microbiome analysis. A manual search of the references within the resulting articles was performed. To investigate possible functional contributions of uterine microbiota to health, studies on microbiota of other body sites were additionally assessed.

OUTCOMES

Challenging the view of a sterile uterus is in its infancy and, to date, no conclusions on a 'core uterine microbiome' can be drawn. Nevertheless, evidence for certain microbiota and/or associated compounds in the uterus accumulates. The presence of microbiota or their constituent molecules, such as polysaccharide A of the Bacteroides fragilis capsule, go together with healthy physiological function. Lessons learned from the gut microbiome suggest that the microbiota of the uterus may potentially modulate immune cell subsets needed for implantation and have implications for tissue morphology. Microbiota can also be crucial in protection against uterine infections by defending their niche and competing with pathogens. Our review highlights the need for well-designed studies on a 'baseline' microbial state of the uterus representing the optimal starting point for implantation and subsequent placenta formation.

WIDER IMPLICATIONS

The complex interplay of processes and cells involved in healthy pregnancy is still poorly understood. The correct receptive endometrial state, including the local immune environment, is crucial not only for fertility but also placenta formation since initiation of placentation highly depends on interaction with immune cells. Implantation failure, recurrent pregnancy loss, and other pathologies of endometrium and placenta, such as pre-eclampsia, represent an increasing societal burden. More robust studies are needed to investigate uterine colonization. Based on current data, future research needs to include the uterine microbiome as a relevant factor in order to understand the players needed for healthy pregnancy.

Angiogenic Properties of Menstrual Stem Cells Are Impaired in Women with a History of Preeclampsia

Preeclampsia is a pregnancy-specific disorder defined by the new onset of hypertension and proteinuria after 20 weeks of gestation. Although its precise etiology is still unknown, there is evidence suggesting that it may be a consequence of impaired decidual and stromal cell function. Recently, a stem cell population derived from endometrial tissue and isolated from menstrual effluent called menstrual stem cells (MenSCs) has been identified. MenSCs exhibit important angiogenic and inflammatory properties that may contribute to both normal and pathological complications of implantation and placentation, including preeclampsia. We hypothesized that the angiogenic and inflammatory activity of MenSCs is altered in women who have a past history of preeclampsia and that this phenotype persists postpartum. The primary outcome measures were stromal progenitor cell formation, in vitro induction of endothelial tube formation, and release of proinflammatory cytokines. MenSCs obtained from women with a previous normal or preeclamptic pregnancy displayed similar phenotypic characteristics, tri-differentiation capacity, and proliferation. MenSCs derived from women who had preeclampsia on their previous pregnancy had reduced angiogenic capacity (~30% fewer junctions and nodes, p < 0.05) and stromal progenitor cell formation (<50% measured at a serial dilution of 1 : 10.000, p < 0.05) when compared to controls. In vitro, MenSCs obtained from patients with a history of preeclampsia expressed less endoglin and secreted less VEGF but more IL-6 than controls did. These data are consistent with the hypothesis that the angiogenic and inflammatory properties of MenSCs of women with a previous pregnancy complicated by preeclampsia have reduced angiogenic capacity and are more proinflammatory than those of MenSCs of women with a previous normal pregnancy. This altered phenotype of MenSCs observed following preeclampsia could either be present before the development of the pathology, predisposing the endometrial milieu to and consequently leading to limited vascular remodeling, or be a consequence of preeclampsia itself. The former may afford opportunity for targeted therapeutic intervention; the latter, a putative biomarker for future risk of pregnancy complications.

Decidual cells from women with preeclampsia exhibit inadequate decidualization and reduced sFlt1 suppression

Uterine stromal cell decidualization of maternal tissue is essential for implantation of and local adaptation to the fetal allograft, as well as growth and maintenance of the placenta in healthy pregnancies. Maternal defects in decidualization have been suggested as a possible driver of preeclampsia. Preeclampsia (PE) pregnancies demonstrate shallow implantation, inadequate spiral artery remodeling, and elevated levels of the anti-angiogenic protein, sFlt1. To test whether stromal cells (DSCs) isolated from PE placentas exhibit inadequate re-decidualization and increased expression of sFlt1, DSCs from normotensive (NT-DSCs) and PE (PE-DSCs) placentas were treated for 8 days (D8) with cAMP to induce decidualization and levels of decidualization markers (PRL, IGFBP1, VEGF) and sFlt1 were measured at day 0 (D0), D8, and after reversal of treatment. NT-DSCs achieved statistically significant elevations in PRL and IFGBP1 expression (25.72 [5.78-50.04], p = 0.0008 and 92.09 [1.79-543.10], p = 0.005). PE-DSCs increased PRL and IFGBP1 expression to 6.15 [2.30-10.73] (p = 0.18) and 8.67 [1.64-376.10] (p = 0.04). NT-DSCs reduced sFlt1 expression at D8 to 0.25 [0.17-0.49] (p = 0.0021) compared to 0.31 [0.25-0.82] (p = 0.087) in PE-DSCs. These results show that, when induced to decidualize, PE-DSCs fail to increase expression of decidualization markers to levels achieved by NT-DSCs. sFlt1 expression is higher in PE-DSCs during decidualization, suggesting inadequate suppression during the crucial implantation period. These defects at the maternal fetal interface may lead to the failed spiral artery modification, decreased placental invasion of the uterus, and elevated circulating sFlt1 levels seen in PE pathology.

Porphyromonas gingivalis strain-dependent inhibition of uterine spiral artery remodeling in the pregnant rat

Porphyromonas gingivalis (Pg) is an important periodontal pathogen that is also implicated in pregnancy complications involving defective deep placentation (DDP). We hypothesized that Pg invasion of the placental bed promotes DDP. Pregnant rats were intravenously inoculated with sterile vehicle, Pg strain W83, or A7436 at gestation day (GD) 14 (acute cohort). Nonpregnant rats received repeated oral inoculations for 3 months before breeding (chronic cohort). Tissues and/or sera were collected at GD18 for analysis. Pg infection status was determined by seroconversion (chronic cohort) and by presence of Pg antigen in utero-placental tissues processed for histology and morphometric assessment of spiral artery remodeling. Mesometrial tissues from seropositive dams were analyzed for expression of interleukin 1β, 6, and 10, TNF, TGF-β, follistatin-related protein 3, and inhibin beta A chain since these genes regulate extravillous trophoblast invasion. The in situ distribution of W83 and A7436 antigen in utero-placental tissues was similar in both cohorts. In the acute cohort, mesometrial stromal necrosis was more common with W83, but arteritis was more common with A7436 infection (P < 0.05). Increased vascular necrosis was seen in mesometrium of chronically infected groups (P < 0.05). Only A7436-infected animals had increased fetal deaths, reduced spiral artery remodeling, reduced inhibin beta A expression, and an increased proportion of FSLT3 positive extravillous trophoblasts within spiral arteries. While infection with both Pg strains produced varying pathology of the deep placental bed, only infection with strain A7436 resulted in impaired spiral artery remodeling.

FOXO1 regulates uterine epithelial integrity and progesterone receptor expression critical for embryo implantation

Successful embryo implantation requires a receptive endometrium. Poor uterine receptivity can account for implantation failure in women who experience recurrent pregnancy loss or multiple rounds of unsuccessful in vitro fertilization cycles. Here, we demonstrate that the transcription factor Forkhead Box O1 (FOXO1) is a critical regulator of endometrial receptivity in vivo. Uterine ablation of Foxo1 using the progesterone receptor Cre (PgrCre) mouse model resulted in infertility due to altered epithelial cell polarity and apoptosis, preventing the embryo from penetrating the luminal epithelium. Analysis of the uterine transcriptome after Foxo1 ablation identified alterations in gene expression for transcripts involved in the activation of cell invasion, molecular transport, apoptosis, β-catenin (CTNNB1) signaling pathway, and an increase in PGR signaling. The increase of PGR signaling was due to PGR expression being retained in the uterine epithelium during the window of receptivity. Constitutive expression of epithelial PGR during this receptive period inhibited expression of FOXO1 in the nucleus of the uterine epithelium. The reciprocal expression of PGR and FOXO1 was conserved in human endometrial samples during the proliferative and secretory phase. This demonstrates that expression of FOXO1 and the loss of PGR during the window of receptivity are interrelated and critical for embryo implantation.

Reciprocal changes of H3K27ac and H3K27me3 at the promoter regions of the critical genes for endometrial decidualization

AIM

Decidualization is essential for embryo implantation and placental development. We aimed to obtain transcriptome and epigenome profiles for primary endometrial stromal cells (ESCs) and in vitro decidualized cells.

MATERIALS & METHODS

ESCs isolated from human endometrial tissues remained untreated (D0), or decidualized for 4 days (D4) and 8 days (D8) in the presence of 8-bromo-cAMP and progesterone.

RESULTS

Among the epigenetic modifications examined (DNA methylation, H3K27ac, H3K9me3 and H3K27me3), the H3K27ac patterns changed most dramatically, with a moderate correlation with gene expression changes, upon decidualization. Subsets of up- and down-regulated genes upon decidualization were associated with reciprocal changes of H3K27ac and H3K27me3 modifications at their promoter region, and were enriched with genes essential for decidualization such as WNT4, ZBTB16, PROK1 and GREB1.

CONCLUSION

Our dataset is useful to further elucidate the molecular mechanisms underlying decidualization.

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.

Villous explants from preeclamptic placentas induce sFlt1 in PBMCs: An ex vivo co-culture study

OBJECTIVES

Soluble Flt1 (sFlt1) is an anti-angiogenic protein linked to the pathology of preeclampsia (PE). While the placenta serves as the major organ producing sFlt1 during normal pregnancy, peripheral blood mononuclear cells (PBMCs), endothelial cells, and stromal cells also produce sFlt1. The key question is 'what drives the overexpression of sFlt1 observed during PE?' In the present work we show evidence for sFlt1 over-expression in PBMCs due to interaction with placental villi from PE patients.

STUDY DESIGN

sFlt1 production by PBMCs is estimated by using two blood collection methods with different coagulation chemistry. PBMCs were then cultured with homologous villous explants and heterologous villous explants to determine the effects of the interaction between the two tissues.

MAIN OUTCOME MEASURES

sFlt1 levels were estimated using real time PCR, ELISA, and gel electrophoresis.

RESULTS

Plasma samples obtained using CTAD as anti-coagulant showed 16-23% less sFlt1 compared to plasma collected in EDTA. Preeclamptic PBMCs showed higher basal level of sFlt1 mRNA. In addition, we show evidence of placental interaction as a cause of sFlt1 overexpression in PBMCs using homologous and heterologous co-culture system. However, during co-culture, we observed that while the sFlt1 expression in PE PBMCs is increased, PE villous explants show reduced sFlt1 RNA expression.

CONCLUSION

sFlt1 was produced in significant amounts by preeclamptic PBMCs, and ex vivo studies show that the placenta induces this over-expression. In contrast, exposure to PBMCs appears to decrease sFlt1 production by preeclamptic placenta.

Downregulation of decidual SP1 and P300 is associated with severe preeclampsia

Preeclampsia (PE) is a pregnancy-induced disorder characterized by hypertension and proteinuria after 20 weeks of gestation, affecting 5-7% of pregnancies worldwide. So far, the etiology of PE remains poorly understood. Abnormal decidualization is thought to contribute to the development of PE. SP1 belongs to the Sp/KLF superfamily and can recruit P300 to regulate the transcription of several genes. SP1 is also very important for decidualization as it enhances the expression of tissue factor. In this study, we investigated the expression of SP1 and P300 in deciduae and their relationship with PE. A total of 42 decidua samples were collected, of which 21 were from normal pregnant (NP) and 21 from severe PE. SP1 and P300 expression in deciduae and the levels of SP1 and P300 in cultured human endometrial stromal cells (hESCs) and primary hESCs during decidualization were determined. To further investigate the role of SP1 and P300 in human decidualization, RNA interference was used to silence SP1 and P300 in hESCs and primary hESCs. The following results were obtained. We found that the expressions of SP1 and P300 were reduced in decidual tissues with PE compared to those from NP. In the in vitro model of induction of decidualization, we found an increase in both SP1 and P300 levels. Silencing of SP1 and P300 resulted in abnormal decidualization and a significant reduction of decidualization markers such as insulin-like growth factor-binding protein1 and prolactin. Furthermore, the expression of vascular endothelial growth factor was also decreased upon SP1 and P300 silencing. Similar results were observed in primary hESCs. Our results suggest that SP1 and P300 play an important role during decidualization. Dysfunction of SP1 and P300 leads to impaired decidualization and might contribute to PE.

Strategies for investigating the maternal-fetal interface in the first trimester of pregnancy: What can we learn about pathology?

The pathologies of the pregnancy complications pre-eclampsia (PE) and fetal growth restriction (FGR) are established in the first trimester of human pregnancy. In a normal pregnancy, decidual spiral arteries are transformed into wide diameter, non-vasoactive vessels capable of meeting the increased demands of the developing fetus for nutrients and oxygen. Disruption of this transformation is associated with PE and FGR. Very little is known of how these first trimester changes are regulated normally and even less is known about how they are compromised in complicated pregnancies. Interactions between maternal and placental cells are essential for pregnancy to progress and this review will summarise the challenges in investigating this area. We will discuss how first trimester studies of pregnancies with an increased risk of developing PE/FGR have started to provide valuable information about pregnancy at this most dynamic and crucial time. We will discuss where there is scope to progress these studies further by refining the ability to identify compromised pregnancies at an early stage, by integrating information from many cell types from the same pregnancy, and by improving our methods for modelling the maternal-fetal interface in vitro.

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Pathology of PE/FGR begins in the first trimester.

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Investigating pregnancies with increased risk of PE/FGR is giving valuable information.

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This will improve further with advances in identifying compromised pregnancies.