Vessel remodelling, pregnancy hormones and extravillous trophoblast function

The Relationship Between Heavy Metals and Missed Abortion: Using Mediation of Serum Hormones

Accumulating evidence suggests that heavy metal exposure may have adverse effects on the fetal development. Furthermore, disruption of serum hormone homeostasis can result in the adverse pregnancy outcomes. Therefore, this study aimed to investigate the potential association between heavy metals and missed abortion, with a focus on whether serum hormones mediate this relationship. The concentrations of heavy metals and hormones in serum were measured in this case-control study. Statistical models including, logistic regression model, principal component analysis (PCA), and weighted quantile sum (WQS) regression model were employed to examine the relationship between heavy metals, serum hormones, and missed abortion. Furthermore, the mediation analysis was performed to assess the role of serum hormones as potential mediators in this relationship. This study revealed significant associations between heavy metal exposure and missed abortion. Notable, the WQS index weight, which was mainly influenced by copper (Cu) and zine (Zn), is associated with missed abortion. Moreover, heavy metals including manganese (Mn), nickel (Ni), Zn, arsenic (As), Cu, cadmium (Cd), and lead (Pb) were found to be associated with serum levels of β-human chorionic gonadotropin (β-hCG), progesterone (P), estradiol (E2), and lactogen (HPL). In addition, the mediation analysis indicated that β-hCG explained a portion of the association (ranging from 18.77 to 43.51%) of between Mn, Ni, Zn, and As exposure and missed abortion. Serum P levels explained 17.93 to 51.70% of the association between Ni, Cu, and As exposure and missed abortion. Serum E2 levels played a significant mediating role, explaining a portion of the association (ranging from 22.14 to 73.60%) between Mn, Ni, Cu, As, Cd, and Pb exposure and missed abortion. Our results suggested that β-hCG, P, and E2 are one of the potential mediators in the complex relationship between heavy metals exposure and missed abortion. These results highlight the importance of considering both heavy metal exposure and serum hormone levels in understanding the etiology of missed abortion.

Current research of Assisted Reproductive Technology for women with early endometrial cancer and atypical endometrial hyperplasia after conservative treatment

As the incidence of endometrial cancer (EC) and atypical endometrial hyperplasia (AEH) has been increasing, and has shown young trend. It is crucial to study the fertility-preserving treatment of endometrial lesions and fertility-promoting protocols. Age, obesity, and irregular ovulation are not only high-risk factors for endometrial lesions but also key factors affecting female fertility. Assisted reproductive technology (ART) can significantly improve pregnancy outcomes in patients with AEH and EC after conservative treatment. Based on the existing studies, this article reviews the progress of research on pregnancy outcomes of ART and its influencing factors in such patients. It helps physicians in providing optimal fertility guidance.

Assisted reproductive technology-associated risk factors for placenta accreta spectrum after vaginal delivery

This study aimed to investigate assisted reproductive technology (ART) factors associated with placenta accreta spectrum (PAS) after vaginal delivery. This was a registry-based retrospective cohort study using the Japanese national ART registry. Cases of live singleton infants born via vaginal delivery after single embryo transfer (ET) between 2007 and 2020 were included (n = 224,043). PAS was diagnosed in 1412 cases (0.63% of deliveries), including 1360 cases (96.3%) derived from frozen-thawed ET cycles and 52 (3.7%) following fresh ET. Among fresh ET cycles, assisted hatching (AH) (adjusted odds ratio [aOR], 2.5; 95% confidence interval [CI] 1.4-4.7) and blastocyst embryo transfer (aOR, 2.2; 95% CI 1.3-3.9) were associated with a significantly increased risk of PAS. For frozen-thawed ET cycles, hormone replacement cycles (HRCs) constituted the greatest risk factor (aOR, 11.4; 95% CI 8.7-15.0), with PAS occurring in 1.4% of all vaginal deliveries following HRC (1258/91,418 deliveries) compared with only 0.11% following natural cycles (55/47,936). AH was also associated with a significantly increased risk of PAS in frozen-thawed cycles (aOR, 1.2; 95% CI 1.02-1.3). Our findings indicate the need for additional care in the management of patients undergoing vaginal delivery following ART with HRC and AH.

Assisted reproductive technology-associated risk factors for retained products of conception

OBJECTIVE

To evaluate assisted reproductive technology-associated risk factors for retained products of conception among live births.

DESIGN

Registry-based retrospective cohort study.

SETTING

Not applicable.

PATIENT(S)

Cycle-specific data for a total of 369,608 singleton live births after fresh and frozen-thawed embryo transfers (FETs) between 2007 and 2017 were obtained from the Japanese assisted reproductive technology registry.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Retained products of conception after delivery. Odds ratios and 95% confidence intervals for risk factors associated with retained products of conception during fresh and frozen cycles.

RESULT(S)

In total, 132 deliveries (0.04% of eligible assisted reproductive technology registry deliveries) had retained products of conception; 122 (92.4%) of these deliveries occurred after FET transfer cycles. Cases with retained products of conception were significantly more likely to have undergone vaginal delivery than cases without retained products of conception (78.0% vs. 61.1%); they were also more likely to have been complicated with the placenta accreta spectrum (24.2% vs. 0.45%). Among patients undergoing FETs, factors associated with a significantly increased risk of retained products of conception were embryo stage at transfer, use of hormone replacement cycles, and assisted hatching. Use of hormone replacement cycles represented the largest risk factor (adjusted odds ratio, 4.9; 95% confidence interval, 2.0-12.4), such that retained products of conception occurred in 0.05% (51 of 97,958) of deliveries after hormone replacement cycles but only 0.01% (5 of 47,079) of deliveries after natural cycles. Subgroup analysis showed that hormone replacement cycles and assisted hatching remained significant risk factors for retained products of conception in cases without polycystic ovary syndrome and anovulation and cases with vaginal delivery, but not cases with cesarean section. Among fresh embryo transfers, an increased number of retrieved oocytes was the only significant risk factor for retained products of conception.

CONCLUSION(S)

Our analyses demonstrated that most of the cases involving retained products of conception were derived from FETs, and we identified the use of hormone replacement cycles as the largest risk factor for retained products of conception within this group.

Unraveling the molecular mechanisms driving enhanced invasion capability of extravillous trophoblast cells: a comprehensive review

Precise extravillous trophoblast (EVT) invasion is crucial for successful placentation and pregnancy. This review focuses on elucidating the mechanisms that promote heightened EVT invasion. We comprehensively summarize the pivotal roles of hormones, angiogenesis, hypoxia, stress, the extracellular matrix microenvironment, epithelial-to-mesenchymal transition (EMT), immunity, inflammation, programmed cell death, epigenetic modifications, and microbiota in facilitating EVT invasion. The molecular mechanisms underlying enhanced EVT invasion may provide valuable insights into potential pathogenic mechanisms associated with diseases characterized by excessive invasion, such as the placenta accreta spectrum (PAS), thereby offering novel perspectives for managing pregnancy complications related to deficient EVT invasion.

The transcriptional regulatory network modulating human trophoblast stem cells to extravillous trophoblast differentiation

During human pregnancy, extravillous trophoblasts play crucial roles in placental invasion into the maternal decidua and spiral artery remodeling. However, regulatory factors and their action mechanisms modulating human extravillous trophoblast specification have been unknown. By analyzing dynamic changes in transcriptome and enhancer profile during human trophoblast stem cell to extravillous trophoblast differentiation, we define stage-specific regulators, including an early-stage transcription factor, TFAP2C, and multiple late-stage transcription factors. Loss-of-function studies confirm the requirement of all transcription factors identified for adequate differentiation, and we reveal that the dynamic changes in the levels of TFAP2C are essential. Notably, TFAP2C pre-occupies the regulatory elements of the inactive extravillous trophoblast-active genes during the early stage of differentiation, and the late-stage transcription factors directly activate extravillous trophoblast-active genes, including themselves as differentiation further progresses, suggesting sequential actions of transcription factors assuring differentiation. Our results reveal stage-specific transcription factors and their inter-connected regulatory mechanisms modulating extravillous trophoblast differentiation, providing a framework for understanding early human placentation and placenta-related complications.

Immune-regulatory properties of endovascular extravillous trophoblast cells in human placenta

INTRODUCTION

Uterine spiral artery remodeling is the prerequisite for ensuring adequate blood supply to the maternal-fetal interface during human pregnancy. One crucial cellular event in this process involves the extensive replacement of the spiral artery endothelial cells by endovascular extravillous trophoblasts (enEVTs), a subtype of extravillous trophoblasts (EVTs). However, our understanding of the properties of enEVTs remains limited.

METHODS

Human enEVTs in decidual tissues during early pregnancy was purified using flow sorting by specific makers, NCAM1 and HLA-G. The high-throughput RNA sequencing analysis as well as the cytokine antibody array experiments were carried out to analyze for cell properties. Gene ontology (GO) enrichment, kyoto encyclopedia of genes and genomes (KEGG) enrichment, and gene set enrichment analysis (GSEA) were performed on differentially expressed genes of enEVTs. Immunofluorescent assays were used to verify the analysis results.

RESULTS

Both enEVTs and interstitial EVTs (iEVTs) exhibited gene expression patterns typifying EVT characteristics. Intriguingly, enEVTs displayed gene expression associated with immune responses, particularly reminiscent of M2 macrophage characteristics. The active secretion of multiple cytokines and chemokines by enEVTs provided partial validation for their expression pattern of immune-regulatory genes.

DISCUSSION

Our study reveals the immune-regulatory properties of human enEVTs and provides new insights into their functions and mechanisms involved in spiral artery remodeling.

Association between estradiol levels in early pregnancy and risk of preeclampsia after frozen embryo transfer

Introduction

The failure of remodeling the spiral arteries is associated with the pathogenesis of preeclampsia. Estradiol (E2) plays a crucial role in placentation and may be involved in the development of preeclampsia. However, there is a lack of data in this area. This study aims to assess the association between serum estradiol levels in early pregnancy and the risk of preeclampsia.

Methods

We conducted a retrospective cohort study on patients who conceived after frozen embryo transfer (FET) using data from a database at a university-affiliated in vitro fertilization center. The study period spanned from January 1, 2010, to December 31, 2020. Multivariable logistic regression analyses were performed to determine the adjusted effect of E2 levels on the risk of preeclampsia. We compared the odds ratios of preeclampsia across quartiles of E2 levels and assessed their significance.

Results

Serum E2 levels at the fifth gestational week were significantly different between women with and without preeclampsia after FET programmed cycles (607.5 ± 245.4 vs. 545.6 ± 294.4 pg/ml, p=0.009). A multivariable logistic regression model demonstrated that E2 levels in early pregnancy were independent risk factors for preeclampsia. We observed an increased odds ratio of preeclampsia with increasing quartiles of estradiol levels after adjusting for potential confounders in FET programmed cycles. When comparing quartiles 3 and 4 (E2 > 493 pg/ml at the fifth gestational week) to quartiles 1 and 2, the odds ratios of preeclampsia were significantly higher.

Conclusion

We found that serum E2 levels in early pregnancy may impact the risk of preeclampsia, particularly following FET programmed cycles. The association between E2 levels in early pregnancy and preeclampsia deserves further investigation.

Natural cycle frozen embryo transfer: a survey of current assisted reproductive technology practices in the U.S

PURPOSE

Emerging data suggests improved obstetric outcomes with frozen embryo transfer (FET) in an ovulatory or natural cycle (NC-FETs), as compared to programmed endometrial preparation. The objective of this study is to better understand practice patterns and provider attitudes regarding the use of NC-FETs in the United States (U.S.).

METHODS

In this cross-sectional study, an anonymous 22-question survey was emailed to 441 U.S. Assisted Reproductive Technology (ART) clinics to assess the utilization of NC endometrial preparation for FET, protocols used, restrictions to offering NC-FET, and providers' perspectives on advantages and disadvantages of NC-FET. Descriptive statistics were used to analyze survey responses.

RESULT(S)

The survey response rate was 49% (216/441). Seventeen percent of responding clinics did not offer NC-FET. Of the clinics that did not offer NC-FET, 65% had only 1-2 physicians in their practice. Common reasons for not offering NC-FET included "lack of timing predictability for transfer" (81%) and "increased burden on staff/laboratory personnel on holidays and weekends" (54%). Of clinics offering NC-FET, 76% reported < 25% of cycles used the NC for endometrial preparation. Over half (52%) of clinics that offered NC-FET reported having eligibility restrictions for NC-FET. Reported benefits of NC-FET were "patient satisfaction" (18%), "decreased cost of medications" (18%), and "avoidance of intramuscular progesterone" (17%). The attitude towards NC-FET in their clinics was reported as positive by 65% of respondents.

CONCLUSION

NC-FETs are offered by most U.S. ART clinics but are used only in the minority of FET cycles for endometrial preparation, and use is often restricted.

Decreased B7-H3 promotes unexplained recurrent miscarriage via RhoA/ROCK2 signaling pathway and regulates the secretion of decidual NK cells†

The cause for at least 50% of recurrent miscarriages is unclear, which is defined as unexplained recurrent miscarriages. The B7-H1 (PD-L1), a molecule of the B7 family, promotes tumor development by modulating immune evasion, and recent researchers have also attached importance to the role of B7-H3, another molecule of B7 family, in tumor. Based on the similarity between growth and immune response in tumors and pregnancy, we first explored the role of B7-H3 in unexplained recurrent miscarriages. We found reduced levels of B7-H3 in the villus tissue of unexplained recurrent miscarriage patients, and it was mainly expressed on the cell membrane of extravillous trophoblasts. Further, the HTR-8/SVneo and JEG-3 cells were selected to explore the role of B7-H3 in proliferation, apoptosis, tube formation, migration, and invasion. We found that B7-H3 regulated trophoblast migration and invasion via RhoA/ROCK2 signaling pathway. Inflammatory cytokines were detected through enzyme-linked immunosorbent assay after co-culturing with decidual natural killer cells and B7-H3-knockout JEG-3. Results showed that B7-H3 inhibited IL-8 and IP-10 secretion from the decidual natural killer cells. In a CBA/J × DBA/2 abortion-prone mice model, treatment with B7-H3-Fc protein successfully reduced the rate of embryo resorption. In conclusion, our results revealed a possible mechanism by which decreased B7-H3 on trophoblasts of unexplained recurrent miscarriages inhibited trophoblast migration and invasion and increased IL-8 and IP-10 secretion from the decidual natural killer cells. Furthermore, B7-H3 may be a promising new therapeutic target in unexplained recurrent miscarriage patients.

High-throughput screening of toxicants that modulate extravillous trophoblast migration

Migration and subsequent invasion of extravillous trophoblasts into the uterus is essential for proper formation of the placenta. Disruption of these processes may result in poor pregnancy outcomes including preeclampsia, placenta accreta, fetal growth restriction, or fetal death. Currently, there are several methods for quantifying cell migration and invasion in vitro, each with limitations. Therefore, we developed a novel, high-throughput method to screen chemicals for their ability to alter human trophoblast migration. Human HTR8/SVneo trophoblast cells were cultured in Oris™ cell migration plates containing stopper barriers. After EVT cells attached and chemicals were added to media, stoppers were removed thereby creating a cell-free detection zone for migration. Entry of trophoblasts into this zone was monitored through imaging every 6 h and used to calculate a relative cell density. Chemicals known to increase (epidermal growth factor) and decrease (pertussis toxin and cadmium) trophoblast migration were used to validate this in vitro method. Next, a panel of environmental chemicals including bisphenols, mycoestrogens, and flame retardants, were screened for their ability to alter trophoblast invasion. In conclusion, a real-time method to track extravillous trophoblast migration offers potential for screening contaminants as placental toxicants.

Obstetric and perinatal outcomes following frozen and fresh embryo transfer in patients with endometrial hyperplasia and carcinoma: a retrospective study in a high-volume reproductive center

BACKGROUND

There is ongoing debate regarding which embryo transfer procedure can achieve a higher live birth rate. Research has suggested that frozen ET might be beneficial for certain populations, such as hyper-responders. This study aimed to compare outcomes of pregnancies between frozen and fresh embryo transfer cycles in patients with endometrial hyperplasia and carcinoma.

METHODS

This retrospective cohort study was conducted at a high-volume reproductive center from January 2010 to January 2022. Patients who were diagnosed with endometrial hyperplasia with atypia and endometrial carcinoma were included. They all underwent in vitro fertilization after conservative treatment. The primary outcome was live birth after frozen and fresh embryo transfer cycles, and secondary outcomes included perinatal complications and other pregnancy outcomes.

RESULTS

Overall, 259 ET cycles (130 fresh and 129 frozen) were included. The rate of live births per embryo transfer cycle of the whole cohort was 20.8% (54/259), and no significant between-group difference was found after adjusting for potential confounding factors (23.8% vs. 17.8%; adjusted OR, 0.47; 95% CI, 0.21-1.06; p=0.068). Compared to fresh embryo transfer group, the incidence of total maternal complications in the frozen embryo transfer group was significantly higher (30.4% vs. 6.5%, p=0.019). Analyzing each complication as a separate entity, patients in the frozen embryo transfer group had a higher incidence of hypertensive disorders of pregnancy (p=0.028). Multiple logistic regression analysis showed that frozen embryo transfer was related with an increased occurrence of maternal complications (OR, 6.68, 95% CI, 1.01-44.19, p=0.040).

CONCLUSIONS

Among patients with endometrial hyperplasia and carcinoma, the rate of live births was comparable between both embryo transfer procedures, while frozen embryo transfer might be associated with a higher risk of maternal complications compared to that with fresh embryo transfer.

Insulin resistance in women with recurrent miscarriage: a systematic review and meta-analysis

PURPOSE

This review aimed to investigate the association of insulin resistance (IR) in women with recurrent pregnancy loss compared to women with normal pregnancy history.

METHODS

PubMed, EMBASE, the Web of Science and Google Scholar databases were accessed to collect published observational studies that compared IR of recurrent pregnancy loss women with healthy women until the 6^th of October 2022. Outcomes assessed in this review and meta-analysis included fasting blood glucose, fasting plasma insulin, homeostasis model assessment for IR, glucose to insulin ratio. Mean differences, odds ratios with 95% confidence interval were pooled using the fixed or random effect models. Sensitivity analyses were performed to validate the robustness of the results. Review Manager version 5.4.1 and Stata version 8.0 were used.

RESULTS

A total of nineteen studies involving 4453 individuals were included. Recurrent pregnancy loss patients presented significantly higher fasting blood glucose, fasting plasma insulin, homeostasis model assessment for IR, and lower glucose to insulin ratios. Additionally, recurrent pregnancy loss patients had higher rates of IR as defined by abnormal fasting plasma insulin, homeostasis model assessment for IR, and glucose to insulin ratio. Sensitivity analyses validated the robustness of the results.

CONCLUSION

In the current review, we show that recurrent pregnancy loss is associated with a higher degree of IR and highlight the importance of screening and treatment of IR.

The impact of different endometrial preparation protocols on obstetric and neonatal complications in frozen-thawed embryo transfer: a retrospective cohort study of 3,458 singleton deliveries

BACKGROUND

Frozen-thawed embryo transfer (FET) is thought to be associated with obstetric and neonatal complications after in vitro fertilization/intracytoplasmic single sperm injection (IVF/ICSI) treatment. The study aimed to determine whether the endometrial preparation protocol is an influencing factor for these complications.

METHODS

We conducted a retrospective cohort study of 3,458 women who had singleton deliveries after IVF/ICSI-FET treatment at the Centre for Reproductive Medicine of Shanghai First Maternity and Infant Hospital between July 2016 and April 2021. The women were divided into three groups according to the endometrial preparation protocols: 2,029 women with programmed cycles, 959 with natural cycles, and 470 with minimal ovarian stimulation cycles. The primary outcomes were the incidence rates of obstetric and neonatal complications, namely, hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM), intrahepatic cholestasis of pregnancy (ICP), placenta previa, preterm rupture of membranes (PROM), preterm delivery, postpartum haemorrhage, large for gestational age (LGA), small for gestational age (SGA), and macrosomia.

RESULTS

After adjustments for confounding variables by multivariate logistic regression analysis, the results showed that programmed cycles had an increased risk of HDP (aOR = 1.743; 95% CI, 1.110-2.735; P = 0.016) and LGA (aOR = 1.269; 95% CI, 1.011-1.592; P = 0.040) compared with natural cycles. Moreover, programmed cycles also increased the risk of LGA (aOR = 1.459; 95% CI, 1.083-1.965; P = 0.013) but reduced the risk of SGA (aOR = 0.529; 95% CI, 0.348-0.805; P = 0.003) compared with minimal ovarian stimulation cycles. There were no significant differences between natural cycles and minimal ovarian stimulation cycles.

CONCLUSIONS

During IVF/ICSI-FET treatment, the risk of HDP and LGA was increased in women with programmed cycles. Therefore, for patients with thin endometrium, irregular menstruation or no spontaneous ovulation, minimal ovarian stimulation cycles may be a relatively safer option than programmed cycles.

Association between fetal sex and pregnancy outcomes among women with twin pregnancies: a multicenter cross-sectional study

PURPOSE

To examine the frequency and to what extent fetal sex is associated with pregnancy outcomes among twin pregnancies, stratified by chorionicity.

METHODS

This registry-based multicenter cross-sectional study was conducted using the Japan Society of Obstetrics and Gynecology perinatal database between 2007 and 2016. The sample population was restricted to women with twin pregnancies. The main pregnancy-related outcomes included preterm birth, very preterm birth, extremely preterm birth, preeclampsia, twin-to-twin transfusion syndrome (TTTS), and selective intrauterine growth restriction (s-IUGR). Birth weight, small for gestational age (SGA), and fetal death were also investigated.

RESULTS

The primary analysis was performed based on 37,953 women, including 23,804 women with dichorionic diamniotic (DD) twins and 14,149 women with monochorionic diamniotic (MD) twins. Women with male/male DD twins had a significantly higher risk of preterm birth (adjusted risk ratio [aRR]: 1.07, 95% confidence interval [CI]: 1.03-1.10) and a lower risk of preeclampsia (aRR: 0.74, 95% CI: 0.62-0.88) than women with female/female DD twins. Women with male/male MD twins also had a significantly higher risk of preterm birth (aRR: 1.06, 95% CI: 1.04-1.09) than women with female/female MD twins. Risks of preeclampsia, TTTS, and s-IUGR did not differ by sex among MD pregnancies. Male SGA risk was significantly higher among male/male twins than among male/female DD twins. Among MD twins, risks of SGA and fetal death were significantly higher in male/male fetuses.

CONCLUSIONS

This study demonstrated significant associations between fetal sex and several pregnancy outcomes in twin pregnancies, some of which differed by chorionicity.

Adverse obstetric and perinatal outcomes in 2333 singleton pregnancies conceived after different endometrial preparation protocols: a retrospective study in China

BACKGROUP

Frozen-thawed embryo transfer is rising worldwide. One adverse effect of programmed frozen embryo transfer (FET) reported in some studies is an increased risk of adverse obstetric and perinatal outcomes. Meanwhile, body mass index (BMI) also has adverse effect on obstetric and perinatal outcomes. In this study, we investigated that the influence of different endometrial preparation protocols on obstetric and perinatal outcomes and the role of BMI in it.

METHOD

This retrospective cohort study included 2333 singleton deliveries after frozen-thaw embryo transfer at our centre between 2014 and 2021, including 550 cycles with programmed FET, 1783 cycles with true natural cycle FET (tNC-FET). In further analysis according to BMI grouped by Asian criterion, group A (18.5 kg/m² ≤ BMI < 24.00 kg/m²) included 1257 subjects, group B (24 kg/m² ≤ BMI < 28.00 kg/m²) included 503 subjects and group C (BMI ≥ 28 kg/m²) included 573 subjects. Baseline characteristics of the two groups were compared and analyzed. Binary logistic regression analyses were performed to explore the association between obstetric and perinatal outcomes and endometrial preparation protocols.

RESULTS

There were no significant differences in the placenta previa, gestational diabetes mellitus(GDM), preterm premature rupture of membranes (PPROM), cesarean section (CS) and macrosomia between the tNC-FET and programmed FET groups (P > 0.05). The programmed FET cycles were associated to a higher risk of pregnancy-induced hypertension (PIH) compared with the tNC-FET cycles (7.3% vs 4.4%, crude OR 1.71[1.16-2.54]; adjusted OR 1.845[1.03-3.30]). After dividing the patients into three groups according to the BMI, The programmed FET cycles were associated to a higher risk of PIH in group C (14.4% vs 6.2%, crude OR 2.55 [1.42-4.55]; adjusted OR 4.71 [1.77-12.55]) compared with the tNC-FET cycles. But there was no statistically significant difference in group A and group B. Programmed FET group compared with the tNC-FET group, the risk of PIH increase as the body mass index increase.

CONCLUSION

This study showed a tendency toward increasing risk of PIH in programmed FET cycle compared with the tNC-FET cycle, and the risk of PIH increases as BMI increases. Increased risk of preterm birth and low birth weight is linked to increased risk of PIH.

Follistatin dysregulation impaired trophoblast biological functions by GDF11-Smad2/3 axis in preeclampsia placentas

INTRODUCTION

Preeclampsia (PE) is one of the main causes of maternal, fetal, and neonatal mortality. So far, the underlying mechanism of this pregnancy-specific syndrome remains unelucidated. The expression of Follistatin (FST) decreased in maternal serum (especially early onset severe PE) and placental trophoblasts of PE patients. However, whether FST-deficiency in preeclamptic placentas alters trophoblast function remains to be determined.

METHODS

Trophoblast cell lines were cultured in vitro and LV3 short hairpin RNA (shRNA) was used to silence FST. Growth and differentiation factor 11 (GDF11) expression level in placentas and serum were detected by immunohistochemistry and enzyme-linked immune-sorbent assay, respectively. To verify the effect of reduced FST expression on trophoblasts, microRNA-24-3p, which was predicted to target the 3'-untranslated region (3'-UTR) of FST, was screened out, and miR-24-3p mimic, inhibitor was used to regulate FST expression in trophoblasts.

RESULTS

Downregulation of FST significantly enhanced the apoptosis and impaired migration and invasion of trophoblast. Reduced FST caused the upregulation of GDF11 in trophoblasts. Interestingly, GDF11 reduced in preeclamptic placental microvascular endothelial cells. Dysregulation of FST-GDF11-Smad2/3 signaling pathway, leading to increased apoptosis of trophoblast. Expression levels of miR-24-3p, was significantly elevated in preeclamptic placentas. Trophoblast cells transfected with miR-24-3p mimics displayed impaired migration and invasion and increased apoptosis. Treated by miR-24-3p inhibitor, trophoblast cells exhibited rescued function.

DISCUSSION

FST-deficiency impaired trophoblast function by upregulating GDF11 levels in trophoblasts. The regulation of FST-GDF11-Smad2/3 axis by microRNAs mimic or inhibitor may be critical to trophoblast function regulation and helps to deepen our understanding of the molecular mechanism of PE.

The impact of endometrial preparation for frozen embryo transfer on maternal and neonatal outcomes: a review

The use of frozen embryo transfer in assisted reproductive technology (ART) has steadily increased since development in the early 1980's. While there are many benefits to delayed frozen embryo transfer, certain adverse perinatal outcomes are noted to be more common in these transfers when compared to fresh transfers, specifically hypertensive disorders of pregnancy. Frozen embryo transfers require coordination between the embryo's developmental stage and the endometrial environment and can occur in either ovulatory or programmed cycles. Though there is no consensus on the ideal method of endometrial preparation prior to frozen embryo transfer, emerging data suggests differences in maternal and neonatal outcomes, specifically increased rates of hypertensive disorders of pregnancy in programmed cycles. Other reported differences include an increased risk of cesarean delivery, placenta accreta, postpartum hemorrhage, low birthweight, preterm birth, post term delivery, macrosomia, large for gestational age, and premature rupture of membranes in programmed cycles. The mechanism by which these differences exist could reflect inherent differences in groups selected for each type of endometrial preparation, the role of super physiologic hormone environments in programmed cycles, or the unique contributions of the corpus luteum in ovulatory cycles that are not present in programmed cycles. Given that existing studies are largely retrospective and have several key limitations, further investigation is needed. Confirmation of these findings has implications for current practice patterns and could enhance understanding of the mechanisms behind important adverse perinatal outcomes in those pursuing assisted reproduction.

The Pivotal Role of the Placenta in Normal and Pathological Pregnancies: A Focus on Preeclampsia, Fetal Growth Restriction, and Maternal Chronic Venous Disease

The placenta is a central structure in pregnancy and has pleiotropic functions. This organ grows incredibly rapidly during this period, acting as a mastermind behind different fetal and maternal processes. The relevance of the placenta extends far beyond the pregnancy, being crucial for fetal programming before birth. Having integrative knowledge of this maternofetal structure helps significantly in understanding the development of pregnancy either in a proper or pathophysiological context. Thus, the aim of this review is to summarize the main features of the placenta, with a special focus on its early development, cytoarchitecture, immunology, and functions in non-pathological conditions. In contraposition, the role of the placenta is examined in preeclampsia, a worrisome hypertensive disorder of pregnancy, in order to describe the pathophysiological implications of the placenta in this disease. Likewise, dysfunction of the placenta in fetal growth restriction, a major consequence of preeclampsia, is also discussed, emphasizing the potential clinical strategies derived. Finally, the emerging role of the placenta in maternal chronic venous disease either as a causative agent or as a consequence of the disease is equally treated.

Placental Dysfunction in Assisted Reproductive Pregnancies: Perinatal, Neonatal and Adult Life Outcomes

Obstetric and newborn outcomes of assisted reproductive technology (ART) pregnancies are associated with significative prevalence of maternal and neonatal adverse health conditions, such as cardiovascular and metabolic diseases. These data are interpreted as anomalies in placentation involving a dysregulation of several molecular factors and pathways. It is not clear which extent of the observed placental alterations are the result of ART and which originate from infertility itself. These two aspects probably act synergically for the final obstetric risk. Data show that mechanisms of inappropriate trophoblast invasion and consequent altered vascular remodeling sustain several clinical conditions, leading to obstetric and perinatal risks often found in ART pregnancies, such as preeclampsia, fetal growth restriction and placenta previa or accreta. The roles of factors such as VEGF, GATA3, PIGF, sFLT-1, sEndoglin, EGFL7, melatonin and of ART conditions, such as short or long embryo cultures, trophectoderm biopsy, embryo cryopreservation, and supraphysiologic endometrium preparation, are discussed. Inflammatory local conditions and epigenetic influence on embryos of ART procedures are important research topics since they may have important consequences on obstetric risk. Prevention and treatment of these conditions represent new frontiers for clinicians and biologists involved in ART, and synergic actions with researchers at molecular levels are advocated.

Pregnancy, preeclampsia and maternal aging: From epidemiology to functional genomics

Women live longer than men but experience greater disability and a longer period of illness as they age. Despite clear sex differences in aging, the impact of pregnancy and its complications, such as preeclampsia, on aging is an underexplored area of geroscience. This review summarizes our current knowledge about the complex links between pregnancy and age-related diseases, including evidence from epidemiology, clinical research, and genetics. We discuss the relationship between normal and pathological pregnancy and maternal aging, using preeclampsia as a primary example. We review the results of human genetics studies of preeclampsia, including genome wide association studies (GWAS), and attempted to catalog genes involved in preeclampsia as a gateway to mechanisms underlying an increased risk of later life cardio- and neuro- vascular events. Lastly, we discuss challenges in interpreting the GWAS of preeclampsia and provide a functional genomics framework for future research needed to fully realize the promise of GWAS in identifying targets for geroprotective prevention and therapeutics against preeclampsia.

The Role and Clinical Interest of Extracellular Vesicles in Pregnancy and Ovarian Cancer

Ovarian cancer and pregnancy are two states in which the host immune system is exposed to novel antigens. Indeed, both the tumor and placenta must invade tissues, remodel vasculature to establish a robust blood supply, and evade detection by the immune system. Interestingly, tumor and placenta tissue use similar mechanisms to induce these necessary changes. One mediator is emerging as a key player in invasion, vascular remodeling, and immune evasion: extracellular vesicles (EVs). Many studies have identified EVs as a key mediator of cell-to-cell communication. Specifically, the cargo carried by EVs, which includes proteins, nucleic acids, and lipids, can interact with cells to induce changes in the target cell ranging from gene expression to migration and metabolism. EVs can promote cell division and tissue invasion, immunosuppression, and angiogenesis which are essential for both cancer and pregnancy. In this review, we examine the role of EVs in ovarian cancer metastasis, chemoresistance, and immune modulation. We then focus on the role of EVs in pregnancy with special attention on the vascular remodeling and regulation of the maternal immune system. Lastly, we discuss the clinical utility of EVs as markers and therapeutics for ovarian cancer and pre-eclampsia.

Changes in vascular function and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight

This study aimed to evaluate vascular function changes and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight. This prospective study performed in pregnant (PG) women and after delivery (not pregnant: NPG) evaluated the endothelial function (EF) and arterial stiffness (AS) by a non-invasive method. We evaluated the heart rate variability (HRV), parasympathetic nervous system (PNS), sympathetic nervous system (SNS) indexes by electrocardiogram (5 min) and the urinary nitrite excretion (NOx). PG increased EF and NOx and decreased AS and HRV. PG decreased the PNS index and augmented the SNS index. The new-born weight positively correlated with the PNS index (Pearson's r: 0.4291; p<.05), NOx, HRV and negatively correlated with AS. In summary, in pregnancy, although haemodynamically, the SNS activation plays a compensatory role, the low rates of PNS inhibition are essential to ensure normal foetal growth.Impact StatementWhat is already known on this subject? In pregnancy, there are adaptive physiological changes in the cardiovascular system that include increases of EF and decreases AS with an SNS activation. The study of HRV lets to predict the SNS and PNS balance and how they affect blood pressure and vascular function.What the results of this study add? Although it is known that SNS activation plays a compensatory role in healthy pregnancy, this study adds the critical role of PNS. Early in pregnancy, the low rates of PNS inhibition are essential to ensure normal foetal growth.What the implications are of these findings for clinical practice and/or further research? The present results show a potential predictive value of SNS and PNS activity early in pregnancy. It will provide valuable information not only on the pregnant woman's vascular function but also on the new-born weight.

Risks of Placenta Previa and Hypertensive Disorders of Pregnancy Are Associated With Endometrial Preparation Methods in Frozen-Thawed Embryo Transfers

Background: Endometrial preparation is essential in frozen-thawed embryo transfer (FET) cycles. Recent studies suggested that different endometrial preparation methods may influence obstetrical complications. However, the association between hormone replacement therapy (HRT) and ovarian stimulation (OS) FET endometrial preparation and obstetrical complications remains unknown.

Methods: This retrospective cohort study included a total of 79,662 confirmed embryo transfer cycles during the period from January 2003 to December 2019. After exclusion, the remaining cases were categorized into an ovarian stimulation FET group (OS FET group, n = 29,121) and a hormone replacement therapy FET group (HRT FET group, n = 26,776) and subjected to the analyses. The primary outcome was the rate of obstetrical complications included placenta previa, placenta abruption, hypertensive disorders of pregnancy (HDP), placenta accreta, gestational diabetes mellitus (GDM), preterm premature rupture of the membrane (pPROM). The secondary outcome was pregnancy outcomes such as live birth rate, birth weight, pre-term and post-term delivery and cesarean sections. In order to minimize the bias, 10 pregnancy-related factors were adjusted in multiple logistic regression analysis.

Results: Placenta previa (0.6 vs. 1.2%, P < 0.001) and HDP (3.5 vs. 5.3%, P < 0.001) were found lower in the OS FET than HRT FET group. Cesarean section was observed lower in the OS than HRT group (76.3 vs. 84.3%, P < 0.001). After adjustment for 10 important pregnancy-related confounding factors, we found that the risk of placenta previa (aOR 0.54, 95% CI 0.39–0.73) and HDP (aOR 0.65, 95% CI 0.57–0.75) and cesarean section (aOR 0.61, 95% CI 0.57–0.66) were still significantly reduced in the OS than HRT group. Furthermore, live birth rates were higher (80.0 vs. 76.0%, P < 0.001), and the miscarriage rate was lower (17.7 vs. 21.3%, P < 0.001) for pregnancies conceived with OS FET than with HRT FET. And the average birth weight was lower in the OS group compared to HRT group (2982.3 ± 636.4 vs. 3025.0 ± 659.0, P < 0.001), as well as the small-for-gestational age (SGA) was higher (8.7 vs. 7.2%, P < 0.001) and the large-for-gestational age (LGA) was lower (7.2 vs. 8.6%, P < 0.001) in the OS group than in the HRT group.

Conclusions: The risks of placenta previa and HDP were lower in patients conceiving after OS FET than in those after HRT FET. Further prospective studies are required to further clarify the mechanism underlying the association between endometrium preparation and obstetrical complications.

Screening Candidate Genes Regulating Placental Development from Trophoblast Transcriptome at Early Pregnancy in Dazu Black Goats (Capra hircus)

Simple Summary

The trophoblast is an original placental tissue whose normal proliferation, differentiation, migration, adhesion, and angiopoiesis are essential for placenta formation and fetal survival during early pregnancy. However, the key genes and molecular mechanisms involved in placenta development in goats are unknown. Herein, the morphology and histological structures of trophoblast tissues from day 20 to 30 of pregnancy were determined. RNA-sequencing was used to screen potential functional genes in common highly expressed and differentially expressed genes. RAP1 signaling pathway was used as the contact center and coordinated with other pathways to regulate placenta development. This study could provide insights into the molecular mechanisms underlying ruminant placentation.

Abstract

This study explored the trophoblast transcriptome to understand potential functional genes involved in early placental development in goats and their enriched signaling pathways. Trophoblast samples were collected from nine Dazu Black goats on days 20, 25, and 30 of pregnancy (D20, D25, and D30). As the pregnancy progressed, the morphology and histological structures showed significant growth, adhesion, and angiogenesis. A total of 23,253 commonly expressed genes (CEGs) and 4439 differently expressed genes (DEGs) were detected by RNA sequencing. The common highly expressed genes (ChEGs) (the top 100 CEGs) with the highest FPKM percentage (29.9%) of all CEGs were annotated to the ribosome pathway and maintain pregnancy. DEGs were abundant in D30 vs. D20 (3715 DEGs). Besides, the DEGs were associated with the inhibition of oxidative phosphorylation and activation of PI3K-Akt, focal adhesion, ECM–receptor interaction, Rap1, and CAM signaling pathways. The RAP1 may be a central pathway since it coordinates with others to regulate the cell proliferation, invasion, migration, and fusion of trophoblasts. qRT-PCR and Western blot analysis confirmed the transcriptional expression in IGF1, VEGFC, RAPGEF3, PIK3CA, AKT3, ITGB3, ITGA11, SPP1, NOS1, and ATP6V0B genes and protein levels in VEGF, RAPGEF3, and Akt. This is the first study of transcriptome profiling in goat placenta and provides diverse genetic resources for further research on placenta development.

Comparing effects and action mechanisms of BPA and BPS on HTR-8/SVneo placental cells

Bisphenol A (BPA) is one of the most investigated compound as a suspected endocrine disrupting chemical. It has been found at nM concentrations in the maternal serum, cord serum, and amniotic fluid and also permeates placental tissues. Attempts are being made to replace BPA with the analog Bisphenol S (BPS). Also BPS was found in maternal and umbilical cord serum, and urine samples from a large population of pregnant women. A few studies investigated BPA impact on the placentation process, and even less are available for BPS. This work aimed to elucidate and compare the effects of BPA and BPS on physiological functions of HTR-8/SVneo cells, derived from extravillous trophoblast of first-trimester pregnancy. Proliferation and migration ability of trophoblast cells were assessed in vitro after exposure to BPA or BPS (10-13 - 10-3 M). Further, induction of the inflammatory response by the bisphenols was studied. To provide insight into the molecular pathways implicated in the responses, experiments were carried out in the presence or absence of tamoxifen as estrogen receptors (ERs) blocker, and U0126 as ERK1/2 phosphorylation inhibitor. Data indicate that BPA significantly affects both proliferation and migration of HTR-8/SVneo cells, through ER and ERK1/2 mediated processes. Differently, BPS only acts on proliferation, again through ER and ERK1/2 mediated processes. BPS, but not BPA, induces secretion of interleukins 6 and 8. Such effect is inhibited by blocking ERK1/2 phosphorylation. To the best of our knowledge, these are the first data showing that BPS affects trophoblast functions through ER/MAPK modulation.

Decidual Natural Killer Cells: A Good Nanny at the Maternal-Fetal Interface During Early Pregnancy

Decidual natural killer (dNK) cells are the tissue-resident and major subpopulation of NK cells at the maternal-fetal interface. It has been demonstrated that dNK cells play pivotal roles in pregnancy, including keeping maternal-fetal immune tolerance, promoting extravillous trophoblast (EVT) cell invasion, and driving uterine spiral artery remodeling. However, the molecular mechanisms haven't been elucidated until recent years. In this review, we systemically introduce the generation, subsets, and surface or soluble molecules of dNK cells, which are critical for maintaining the functions of dNK cells. Further, new functions of dNK cells including well-controlled cytotoxicity, immunosurveillance and immunotrophism supporting via the cell-cell interaction between dNK cells and EVT cells are mainly focused. The molecular mechanisms involved in these functions are also illustrated. Moreover, pregnancy-associated diseases caused by the dNK cells abnormalities are discussed. It will be important for future investigations about the mechanism of maintenance of pregnancy and parturition and potential clinical applications of dNK cells.

Steroid hormones and first trimester vascular remodeling

Successful implantation and placentation require neoangiogenesis and the remodeling of the uterine spiral arteries. Progesterone and estradiol control various of the placental functions, but their role in vascular remodeling remains controversial. Therefore, this chapter aims to summarize the current knowledge regarding the role of steroid hormones in the uteroplacental vascular remodeling during the first trimester of gestation.

Lower risk of adverse perinatal outcomes in natural versus artificial frozen-thawed embryo transfer cycles: a systematic review and meta-analysis

This systematic review of literature and meta-analysis of observational studies reports on perinatal outcomes after frozen embryo transfer (FET). The aim was to determine whether natural cycle frozen embryo transfer (NC-FET) in singleton pregnancies conceived after IVF decreased the risk of adverse perinatal outcomes compared with artificial cycle frozen embryo transfer (AC-FET). Thirteen cohort studies, including 93,201 cycles, met the inclusion criteria. NC-FET was associated with a lower risk of hypertensive disorders in pregnancy (HDP) (RR 0.61, 95% CI 0.50 to 0.73), preeclampsia (RR 0.47, 95% CI 0.42 to 0.53), large for gestational age (LGA) (RR 0.93, 95% CI 0.90 to 0.96) and macrosomia (RR 0.82, 95% CI 0.69 to 0.97) compared with AC-FET. No significant difference was found in the risk of gestational hypertension and small for gestational age. Secondary outcomes assessed were the risk of preterm birth (RR 0.83, 95% CI 0.79 to 0.88); post-term birth (RR 0.48, 95% CI 0.29 to 0.80); low birth weight (RR 0.84, 95% CI 0.80 to 0.89); caesarean section (RR 0.84, 95% CI 0.77 to 0.91); postpartum haemorrhage (RR 0.39, 95% CI 0.35 to 0.45); placental abruption (RR 0.61, 95% CI 0.38 to 0.98); and placenta accreta (RR 0.18, 95% CI 0.10 to 0.33). All were significantly lower with NC-FET compared with AC-FET. In assessing safety, NC-FET significantly decreased the risk of HDP, preeclampsia, LGA, macrosomia, preterm birth, post-term birth, low birth weight, caesarean section, postpartum haemorrhage, placental abruption and placenta accreta. Further randomized controlled trials addressing the effect of NC-FET and AC-FET on maternal and perinatal outcomes are warranted. Clinicians should carefully monitor pregnancies achieved by FET in artificial cycles prenatally, during labour and postnatally.

Increased obstetric and neonatal risks in artificial cycles for frozen embryo transfers?

RESEARCH QUESTION

What are the obstetric and neonatal risks for women conceiving via frozen-thawed embryo transfer (FET) during a modified natural cycle compared with an artificial cycle method.

DESIGN

A follow-up study to the ANTARCTICA randomized controlled trial (RCT) (NTR 1586) conducted in the Netherlands, which showed that modified natural cycle FET (NC-FET) was non-inferior to artificial cycle FET (AC-FET) in terms of live birth rates. The current study collected data on obstetric and neonatal outcomes of 98 women who had a singleton live birth. The main outcome was birthweight; additional outcomes included hypertensive disorder of pregnancy, premature birth, gestational diabetes, obstetric haemorrhage and neonatal outcomes including Apgar scores and admission to the neonatal ward or the neonatal intensive care unit and congenital anomalies.

RESULTS

Data from 82 out of 98 women were analysed according to the per protocol principle. There was no significant difference in the birthweights of children born between groups (mean difference -124 g [-363 g to 114 g]; P = 0.30). Women who conceived by modified NC-FET have a decreased risk of hypertensive disorders of pregnancy compared with AC-FET (relative risk 0.27; 95% CI 0.08-0.94; P = 0.031). Other outcomes, such as rates of premature birth, gestational diabetes or obstetric haemorrhage and neonatal outcomes, were not significantly different.

CONCLUSIONS

The interpretation is that modified NC-FET is the preferred treatment in women with ovulatory cycles undergoing FET when the increased risk of obstetrical complications and potential neonatal complications in AC-FET are considered.

Adverse obstetric and perinatal outcomes in 1,136 singleton pregnancies conceived after programmed frozen embryo transfer (FET) compared with natural cycle FET

OBJECTIVE

To investigate whether obstetric and perinatal outcomes in pregnancies differ after different frozen embryo transfer (FET) protocols.

DESIGN

Register-based cohort study.

SETTING

Not applicable.

PATIENT(S)

All singleton deliveries after assisted reproductive technology in Denmark from 2006 to 2014. Data consisted of 1,136 deliveries after frozen in vitro fertilization. Frozen embryo transfer cycles were grouped by type of FET protocol: programmed FET (n = 357); modified natural cycle FET (n = 611); and true natural cycle FET (n = 168).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Obstetric outcomes (hypertensive disorders in pregnancy, preterm prelabor rupture of membranes, placenta previa, placental abruption, induction of labor, postpartum hemorrhage, and cesarean section) and perinatal outcomes (post-term birth, preterm birth, birth weight, small for gestational age, large for gestational age).

RESULT(S)

The risk of hypertensive disorders in pregnancy, postpartum hemorrhage, and cesarean section was significantly higher after programmed FET compared with natural cycle FET (modified natural cycle FET and true natural cycle FET). A higher risk of birth weight > 4,500 g was observed in the programmed FET group compared with natural cycle FET.

CONCLUSION(S)

This study shows that obstetric and perinatal outcomes are adversely affected in programmed FET cycles. Hence, when possible, an endometrial preparation with the creation of a corpus luteum should be considered. Properly sized randomized controlled trials of FET in programmed cycle versus natural cycle including perinatal outcomes are warranted in the future.

CLINICAL TRIAL REGISTRATION NUMBER

ISRCTN11780826.

CD97 Is Decreased in Preeclamptic Placentas and Promotes Human Trophoblast Invasion Through PI3K/Akt/mTOR Signaling Pathway

Preeclampsia (PE) is a pregnancy disorder leading to the morbidity and mortality. Despite the development of the understanding of etiology, the only effective treatment of PE is the delivery of the placenta. An improved mastery on the regulation of trophoblast invasion could be meaningful to alleviate the disease burden of PE. Relative expression of CD97 in PE and normal placental tissues was evaluated by quantitative real-time polymerase chain reaction, immunohistology, and Western blot. The CD97 siRNA and expression vector was transfected to cultured human trophoblast HTR-8/SVneo, and the cell invasion as well as the protein expression in PI3K/Akt/mTOR signaling pathway were evaluated. Expression of CD97 is significantly downregulated in PE placental tissues compared to normal controls. The Si-CD97 inhibits HTR-8/SVneo trophoblast cells invasion, as well as the activation of PI3K/Akt/mTOR signaling pathway. In accordance, overexpression of CD97 promotes trophoblast cell invasion. In addition, CD97 regulates FOXC2 expression and showed similar effects on PI3K/Akt/mTOR signaling pathway as specific FOXC2 inhibitor. In short, this study demonstrated the downregulation of CD97 expression in preeclamptic placentas. Further mechanism investigation revealed that CD97 promoted trophoblast invasion by targeting FOXC2 via PI3K/Akt/mTOR signaling pathway, laying the foundation for the development of PE intervention strategy by targeting CD97 in placentation and pathogenesis of PE.

GDF8 Promotes the Cell Invasiveness in Human Trophoblasts by Upregulating the Expression of Follistatin-Like 3 Through the ALK5-SMAD2/3 Signaling Pathway

Growth differentiation factor 8 (GDF8) and its antagonist follistatin-like 3 (FSTL3) are expressed in the placenta during early pregnancy. These two factors may have a role to play in the regulation of normal placentation. However, whether GDF8 can regulate the expression of FSTL3 in human trophoblasts remains to be elucidated. In this study, we aimed to investigate the effects of GDF8 on the expression of FSTL3 and the underlying molecular mechanisms using human trophoblasts as a study model. Our results showed that GDF8 significantly upregulates the expression and production of FSTL3, which further promotes cell invasiveness in immortalized extravillous cytotrophoblast cells and primary extravillous cytotrophoblast cells obtained from human first-trimester placentae. Additionally, using an siRNA-mediated knockdown approach, we found that this regulatory effect is most likely mediated by the ALK5-Sma- and Mad-related protein (SMAD)2/3-induced signaling pathway. These findings deepen our understanding of the functional roles of GDF8 and FSTL3 in the regulation of cell invasiveness of trophoblasts.

miR-18a Contributes to Preeclampsia by Downregulating Smad2 (Full Length) and Reducing TGF-β Signaling

The study investigated the regulation of Smad2 by miR-18a and its role in preeclampsia (PE). Bioinformatics analysis showed that both Smad2 and Smad3 were the predicted targets for miR-18a. Mass spectrum analysis showed that two mature Smad2 isoforms existed in human placenta: full length, Smad2(FL), and that lacking exon3, Smad2(Δexon3). The protein level of Smad2(FL), but not Smad2(Δexon3) or Smad3, was significantly increased in severe PE (sPE) placenta, which was inversely correlated with the level of miR-18a. Elevated Smad2(FL) phosphorylation level appeared in sPE placenta, and Smad2 was colocalized with miR-18a in various subtypes of trophoblasts in human placenta. Smad2(FL) was validated as the direct target of miR-18a in HTR8/SVneo cells. miR-18a enhanced trophoblast cell invasion, which was blocked by the overexpression of Smad2(FL). Furthermore, overexpression of miR-18a repressed Smad2 activation and the inhibition of trophoblast cell invasion by transforming growth factor-β (TGF-β). In conclusion, our results suggest that miR-18a inhibits the expression of Smad2(FL), but not Smad2(Δexon3) or Smad3, which can reduce TGF-β signaling, leading to the enhancement of trophoblast cell invasion. A lack of miR-18a, which results in the upregulation of Smad2(FL), contributes to the development of PE.

Endometrial preparation methods for frozen-thawed embryo transfer are associated with altered risks of hypertensive disorders of pregnancy, placenta accreta, and gestational diabetes mellitus

STUDY QUESTION

What were the risks with regard to the pregnancy outcomes of patients who conceived by frozen-thawed embryo transfer (FET) during a hormone replacement cycle (HRC-FET)?

SUMMARY ANSWER

The patients who conceived by HRC-FET had increased risks of hypertensive disorders of pregnancy (HDP) and placenta accreta and a reduced risk of gestational diabetes mellitus (GDM) in comparison to those who conceived by FET during a natural ovulatory cycle (NC-FET).

WHAT IS KNOWN ALREADY

Previous studies have shown that pregnancy and live-birth rates after HRC-FET and NC-FET are comparable. Little has been clarified regarding the association between endometrium preparation and other pregnancy outcomes.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of patients who conceived after HRC-FET and those who conceived after NC-FET was performed based on the Japanese assisted reproductive technology registry in 2014.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The pregnancy outcomes were compared between NC-FET (n = 29 760) and HRC-FET (n = 75 474) cycles. Multiple logistic regression analyses were performed to investigate the potential confounding factors.

MAIN RESULTS AND THE ROLE OF CHANCE

The pregnancy rate (32.1% vs 36.1%) and the live birth rate among pregnancies (67.1% vs 71.9%) in HRC-FET cycles were significantly lower than those in NC-FET cycles. A multiple logistic regression analysis showed that pregnancies after HRC-FET had increased odds of HDPs [adjusted odds ratio, 1.43; 95% confidence interval (CI), 1.14-1.80] and placenta accreta (adjusted odds ratio, 6.91; 95% CI, 2.87-16.66) and decreased odds for GDM (adjusted odds ratio, 0.52; 95% CI, 0.40-0.68) in comparison to pregnancies after NC-FET.

LIMITATIONS, REASONS FOR CAUTION

Our study was retrospective in nature, and some cases were excluded due to missing data. The implication of bias and residual confounding factors such as body mass index, alcohol consumption, and smoking habits should be considered in other observational studies.

WIDER IMPLICATIONS OF THE FINDINGS

Pregnancies following HRC-FET are associated with higher risks of HDPs and placenta accreta and a lower risk of GDM. The association between the endometrium preparation method and obstetrical complication merits further attention.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was obtained for this work. The authors declare no conflicts of interest in association with the present study.

TRIAL REGISTRATION NUMBER

Not applicable.

Molecular Mechanisms of Trophoblast Dysfunction Mediated by Imbalance between STOX1 Isoforms

STOX1 is a transcription factor involved in preeclampsia and Alzheimer disease. We show that the knock-down of the gene induces rather mild effect on gene expression in trophoblast cell lines (BeWo). We identified binding sites of STOX1 shared by the two major isoforms, STOX1A and STOX1B. Profiling gene expression of cells overexpressing either STOX1A or STOX1B, we identified genes downregulated by both isoforms, with a STOX1 binding site in their promoters. Among those, STOX1-induced Annexin A1 downregulation led to abolished membrane repair in BeWo cells. By contrast, overexpression of STOX1A or B has opposite effects on trophoblast fusion (acceleration and inhibition, respectively) accompanied by syncytin genes deregulation. Also, STOX1A overexpression led to abnormal regulation of oxidative and nitrosative stress. In sum, our work shows that STOX1 isoform imbalance is a cause of gene expression deregulation in the trophoblast, possibly leading to placental dysfunction and preeclampsia.

Autophagy regulates abnormal placentation induced by folate deficiency in mice

Folate deficiency has been linked to a wide range of pregnancy disorders. Most research about folate-deficiency has focused on the embryo itself, little attention has been paid to possible effects on the placenta. According to our results, the morphology of the placenta, endocrine function, and the expression of genes involved in placental differentiation were all abnormal in folate-deficient mice on days 10, 12, and 14 of pregnancy. Similar results were found in human placenta explants cultured in folate-deficient medium. Autophagy is an inducible catabolic process activated by external nutrients starvation. Here we explored further, whether autophagy was involved in the abnormal placentation caused by folate-deficiency. The aberrant number of autophagosomes measured by transmission electron microscopy and the deviant expression of autophagy-related markers showed a disordered autophagy in placentas under conditions of folate-deficiency in vivo and in vitro dual-fluorescence mRFP-eGFP-LC3 analysis indicated enhanced autophagy was detected in HTR8/SVneo cells incubated in folate-deficient medium. Importantly, the placentation impairment in mice and human placenta explants could be recovered by inhibiting placental autophagy using 3-MA. In addition, the apoptosis and invasive capability of HTR8/SVneo cells were obviously suppressed by folate deficiency but notably elevated by 3-MA. These data suggest that folate deficiency can impair placentation and autophagy is a key factor in this. However, the signal pathway by which folate deficiency causes aberrant autophagy needs to be explored further.

Circadian clock gene Clock is involved in the pathogenesis of preeclampsia through hypoxia

OBJECTIVE

To study the effect of the circadian clock gene Clock on the biological behavior of trophoblasts and its role in the pathogenesis of preeclampsia.

METHODS

Quantitative real-time polymerase chain reaction (RT-qPCR) was used to detect the expression of Clock mRNA. Western blot and immunohistochemistry were used to detect the expression and localization of Clock protein. CoCl₂ was used to induce the hypoxic trophoblast cells. Cell invasion assay, wound healing assay and MTT assays were used to detect the invasion, migration, and proliferation ability. Reduced uterine perfusion pressure (RUPP) rat model was established by surgically clamping the abdominal aorta and uterine arteries. Transfection of si-Clock was used to silencing the expression of Clock.

RESULTS

Clock mRNA expression was increased in placenta of preeclampsia and CoCl₂-induced hypoxic trophoblasts, while protein was decreased. But the trend was opposite in RUPP rat models. Hypoxia can also change the expression rhythm of Clock. The proliferation, migration and invasion ability of trophoblasts decreased after hypoxia, while these abilities restored to near normal level after silencing Clock.

CONCLUSION

The expression of Clock gene in human placenta tissue, hypoxia cell model and RUPP rat model suggests that it may regulate the biological behavior of trophoblast cells through hypoxia, and then participate in the pathogenesis of preeclampsia.

Progesterone Intramuscularly or Vaginally Administration May Not Change Live Birth Rate or Neonatal Outcomes in Artificial Frozen-Thawed Embryo Transfer Cycles

BACKGROUNDS

Previous studies suggested that singletons from frozen-thawed embryo transfer (FET) were associated with higher risk of large, post-date babies and adverse obstetrical outcomes compared to fresh transfer and natural pregnancy. No data available revealed whether the adverse perinatal outcomes were associated with aberrantly high progesterone level from different endometrium preparations in HRT-FET cycle. This study aimed to compare the impact of progesterone intramuscularly and vaginally regimens on neonatal outcomes in HRT-FET cycles.

METHODS

A total of 856 HRT-FET cycles from a fertility center from 2015 to 2018 were retrospectively analyzed. All patients had their first FET with two cleavage-staged embryos transferred. Endometrial preparation was performed with sequential administration of estrogen followed by progesterone intramuscularly 60 mg per day or vaginal gel Crinone 90 mg per day. Pregnancy outcomes including live birth rate, singleton birthweight, large for gestational age (LGA) rate, small for gestational age (SGA) rate, and preterm delivery rate were analyzed. Student's t test, Mann-Whitney U-test, Chi square analysis, and multivariable logistic regression were used where appropriate. Differences were considered significant if p < 0.05.

RESULTS

No significant difference of live birth rate was found between different progesterone regimens (Adjusted OR 1.128, 95% CI 0.842, 1.511, p = 0.420). Neonatal outcomes like singleton birthweight (p = 0.744), preterm delivery rate (Adjusted OR 1.920, 95% CI 0.603, 6.11, p = 0.269), SGA (Adjusted OR 0.227, 95% CI 0.027, 1.934, p = 0.175), and LGA rate (Adjusted OR 0.862, 95% CI 0.425, 1.749, p=0.681) were not different between two progesterone regimens. Serum P level >41.82 pmol/L at 14 day post-FET was associated with higher live birth rate than serum P level ≤41.82 pmol/L in HRT-FET cycles when progesterone was intramuscularly delivered (Adjusted OR 1.690, 95% CI 1.002, 2.849, p = 0.049). But singleton birthweight, preterm delivery rate, SGA and LGA rate were not different between these two groups.

CONCLUSIONS

Relatively higher serum progesterone level induced by intramuscular regimen did not change live birth rate or neonatal outcomes compared to vaginal regimen. Monitoring serum progesterone level and optimizing progesterone dose of intramuscular progesterone as needed in HRT-FET cycles has a role in improving live birth rate without impact on neonatal outcomes.

Extravillous trophoblast invasion accelerated by WNT3A, 5A, and 10B via CD44

INTRODUCTION

Appropriate extravillous trophoblast (EVT) invasion is essential for successful pregnancy. Previously, we showed that EVTs express CD44, which accelerated EVT invasion. However, its regulation mechanism via CD44 remains unknown. Our hypothesis was that WNT signaling enhanced EVT invasion via CD44. To test this hypothesis, we investigated the effects of WNT ligands on CD44 expression and EVT invasion using EVT cell lines and isolated primary EVTs.

METHODS

We used EVT cell lines (HTR8/SVneo and HChEpC1b) and isolated primary EVTs, extracted from first-trimester trophoblasts. The cells were supplemented with WNT3A, 5A, and 10B. We examined cell invasion and the expressions of CD44 and matrix metalloproteinase (MMP) 9. Next, to clarify the pathway of WNT10B in EVTs, we knock-downed WNT10B using siRNA and activated or inhibited the WNT canonical pathway using an activator (lithium chloride) or inhibitor (FH535, XAV939) with WNT10B addition.

RESULTS

WNT3A, 5A, and 10B accelerated the invasion in the EVT lines and isolated primary EVTs. The expressions of CD44 and MMP9 were also upregulated by WNT ligands. WNT10B knockdown significantly inhibited EVT invasion concomitantly with CD44 expression. The WNT canonical pathway activator upregulated CD44 expression and its inhibitor downregulated it with WNT10B addition.

CONCLUSIONS

The present study is the first to show the possibility that WNT3A, WNT5A, and WNT10B exist upstream of CD44 in EVTs. Among them, WNT10B may be a novel accelerator of EVT invasion. WNT signaling mediated by multiple WNT ligands may contribute to EVT invasion.

Vascular endothelial growth factor C participates in regulation of maspin in extravillous trophoblast cell migration and invasion

Mammary serine protease inhibitor (maspin ; also known as serpin family B member 5 (SERPINB5)) plays a vital role in regulating the biological functions of extravillous trophoblast (EVT) cells, but the mechanism remains unclear. Vascular endothelial growth factor (VEGF ) C is a signature angiogenic molecule expressed and secreted by first-trimester trophoblasts, and bioinformatics analyses has revealed upregulation of VEGFC in pre-eclampsia. The aim of this study was to explore whether maspin regulates EVT cells by regulating the expression of VEGFC . Reverse transcription-polymerase chain reaction and western blotting were used to investigate the effects of hypoxia on the expression of VEGFC in EVT cells. Cells were treated with recombinant (r) maspin and decitabine (to selectively inhibit DNA methyltransferases and then upregulate maspin gene expression), and the effects on VEGFC expression evaluated. In addition, the effects of rVEGFC on the biological functions of EVT cells invitro were evaluated using cell migration and invasion assays. Hypoxia increased the expression of VEGFC in EVT cells. rMaspin upregulated the expression of VEGFC in normoxic EVT cells, and downregulated the expression of VEGFC in hypoxic EVT cells at 24h. Decitabine increased VEGFC expression in normoxic EVT cells, but had no significant effect on VEGFC expression in hypoxic EVT cells. rVEGFC promoted the migration and invasion of normoxic EVT cells and inhibited the invasion of hypoxic EVT cells. These results suggest that VEGFC is involved in the regulation of maspin in EVT cell migration and invasion. However, other molecular mechanisms may be involved and require further investigation.

Role of pregnancy hormones and hormonal interaction on the maternal cardiovascular system: a literature review

Hormones have a vital duty in the conservation of physiological cardiovascular function during pregnancy. Alterations in oestrogen, progesterone and prolactin levels are associated with changes in the cardiovascular system to support the growing foetus and counteract pregnancy stresses. Pregnancy hormones are, however, also linked to numerous pathophysiological outcomes on the cardiovascular system. The expression and effects of the three main pregnancy hormones (oestrogen, prolactin and progesterone) vary depending on the gestation period. However, the reaction of a target cell also depends on the abundance of hormone receptors and impacts put forth by other hormones. Hormonal interaction may be synergistic, antagonistic or permissive. It is crucial to explore the cross talk of pregnancy hormones during gestation, as this may have a greater impact on the overall changes to the cardiovascular system.

CD97 Is Decreased in Preeclamptic Placentas and Promotes Human Trophoblast Invasion Through PI3K/Akt/mTOR Signaling Pathway

Preeclampsia (PE) is a pregnancy disorder leading to the morbidity and mortality. Despite the development of the understanding of etiology, the only effective treatment of PE is the delivery of the placenta. An improved mastery on the regulation of trophoblast invasion could be meaningful to alleviate the disease burden of PE. Relative expression of CD97 in PE and normal placental tissues was evaluated by quantitative real-time polymerase chain reaction, immunohistology, and Western blot. The CD97 siRNA and expression vector was transfected to cultured human trophoblast HTR-8/SVneo, and the cell invasion as well as the protein expression in PI3K/Akt/mTOR signaling pathway were evaluated. Expression of CD97 is significantly downregulated in PE placental tissues compared to normal controls. The Si-CD97 inhibits HTR-8/SVneo trophoblast cells invasion, as well as the activation of PI3K/Akt/mTOR signaling pathway. In accordance, overexpression of CD97 promotes trophoblast cell invasion. In addition, CD97 regulates FOXC2 expression and showed similar effects on PI3K/Akt/mTOR signaling pathway as specific FOXC2 inhibitor. In short, this study demonstrated the downregulation of CD97 expression in preeclamptic placentas. Further mechanism investigation revealed that CD97 promoted trophoblast invasion by targeting FOXC2 via PI3K/Akt/mTOR signaling pathway, laying the foundation for the development of PE intervention strategy by targeting CD97 in placentation and pathogenesis of PE.

Steroid hormones induce in vitro human first trimester trophoblast tubulogenesis by the lysophosphatidic acid pathway

Successful implantation and placentation requires that extravillous cytotrophoblast acquires an endovascular phenotype and remodels uterine spiral arteries. Progesterone (P4) and estradiol (E2) control many of the placental functions, but their role in vascular remodeling remains controversial. Here, we investigated whether P4 and E2 regulate the acquisition of the human first trimester trophoblast endovascular phenotype, and the participation of the lysophosphatidic acid pathway. For this purpose, human first trimester HTR-8/SVneo cells were seeded on Geltrex and assayed for capillary-like tube formation. P4 and E2 increased HTR-8/SVneo tube formation in a concentration-dependent manner and this effect is mediated by the LPA3 receptor. Moreover, sex steroids increased the mRNA levels of the main enzyme that produce lysophosphatidic acid (lysophospholipase-D) but did not regulate LPA3 mRNA levels. Overall, we demonstrate that steroid hormones regulate HTR-8/SVneo trophoblast capillary-like structures formation and we propose that this process could be modulated directly or indirectly by mechanisms associated to the LPA/LPA3 pathway.

Involvement of follistatin-like 3 in preeclampsia

INTRODUCTION

Preeclampsia is a main cause of maternal and perinatal mortality and morbidity. The expression of follistatin-like 3 (FSTL3) is enhanced in maternal serum and placenta of preeclamptic women. However, whether FSTL3 is involved in the pathophysiologic of preeclampsia has not been clarified yet.

METHOD

Trophoblast cell lines Swan71 and JAR cells were cultured and siRNA was used to silence FSTL3. The expression of FSTL3 was determined by Western blotting. The matrigel-coated transwell and wound healing assays were used to assess invasion and migration, cell proliferation and apoptosis were detected by CCK-8 and flow cytometric analysis, respectively. Oil red O staining was used to detect the lipid storage in trophoblast.

RESULTS

Hypoxia culture significantly enhanced the expression of FSTL3 by trophoblast. Down-regulation of FSTL3 significantly suppressed the proliferation, migration, invasion and lipid storage but increased apoptosis of trophoblast.

DISCUSSION

Aberrant expression of FSTL3 in preeclampsia led to the dysfunction of trophoblast, indicating its involvement in the pathogenesis of preeclampsia.

Temporal changes of the endothelin system in human cytotrophoblasts during the first trimester of pregnancy

The first trimester of pregnancy is characterized by continuous proliferation, invasion and differentiation of cytotrophoblasts. These processes are precisely controlled both, in space and time by molecules such as endothelin-1 (ET-1). ET-1 is expressed in human first trimester trophoblast and is known to stimulate cytotrophoblast proliferation through endothelin A and B receptor subtypes (ET(A) and ET(B)), and cytotrophoblast invasion through ET(B). However, temporal changes of the ET system during the first trimester of pregnancy have not been previously studied. This study tested the hypothesis that ET-1 release, ET(A) and ET(B) expression are increased towards the end of the first trimester of pregnancy (weeks 10-12 vs. weeks 6-9), resulting in increased cytotrophoblast proliferation and invasion. Tissue samples were obtained from 17 surgical pregnancy interruptions (week 6-9: n=9; week 10-12: n=8). After cytotrophoblast isolation, the invasive and proliferative phenotypes were immune-separated by an alpha(6)-integrin antibody. Both proliferative and invasive cytotrophoblasts were cultured separately on plastic or Matrigel for 24 h. ET-1 release into the culture medium of both cytotrophoblast subtypes was measured by radioimmunoassay. ET(A) and ET(B) mRNA expression was measured by RT-PCR, and the ET-1 effect on cytotrophoblast proliferation and invasion was determined using proliferation and invasion assays, respectively. ET-1 release increased from early to late first trimester of pregnancy in both proliferative (1.8-4.5 fold) and invasive cytotrophoblasts (9.3-28 fold), especially when cultured on Matrigel. This was paralleled by less ET(B) mRNA on invasive cytotrophoblasts independent of the time period in first trimester, whereas ET(A) expression was similar on proliferative an invasive cytotrophoblasts. Proliferation and invasion of cytotrophoblasts under control conditions decreased from early to late first trimester. ET-1 stimulated both processes at both periods with the most pronounced effect (7-fold) on invasion in late first trimester. The ET-1/ET-receptor system changes between weeks 6-9 and 10-12 in pregnancy. Our data suggest an autocrine and endocrine ET-1 effect, which is stronger in late than in early first trimester of pregnancy paralleled by different stimulatory effects on trophoblast invasion and proliferation. In general, this suggests time as an additional effector of the critical processes governing placental development in the first trimester of human pregnancy.

Inside the Endometrial Cell Signaling Subway: Mind the Gap(s)

Endometrial cells perceive and respond to their microenvironment forming the basis of endometrial homeostasis. Errors in endometrial cell signaling are responsible for a wide spectrum of endometrial pathologies ranging from infertility to cancer. Intensive research over the years has been decoding the sophisticated molecular means by which endometrial cells communicate to each other and with the embryo. The objective of this review is to provide the scientific community with the first overview of key endometrial cell signaling pathways operating throughout the menstrual cycle. On this basis, a comprehensive and critical assessment of the literature was performed to provide the tools for the authorship of this narrative review summarizing the pivotal components and signaling cascades operating during seven endometrial cell fate “routes”: proliferation, decidualization, implantation, migration, breakdown, regeneration, and angiogenesis. Albeit schematically presented as separate transit routes in a subway network and narrated in a distinct fashion, the majority of the time these routes overlap or occur simultaneously within endometrial cells. This review facilitates identification of novel trajectories of research in endometrial cellular communication and signaling. The meticulous study of endometrial signaling pathways potentiates both the discovery of novel therapeutic targets to tackle disease and vanguard fertility approaches.