Implantation and the survival of early pregnancy

T3-THR Signaling Governed by DIO2 Contributes to Endometrial Receptivity by Regulating Epithelial Cell Membrane Fluidity

Maintaining normal thyroid function is crucial in pregnancy, and the thyroid hormone signaling pathway is involved in embryo implantation. However, the regulation of iodothyronine deiodinase 2 (DIO2), which is the central hub controlling thyroid hormone signaling, and the intracellular pathway activated by triiodothyronine (T3) binding to the thyroid hormone receptor (THR) in endometrial cells, remains unclear. Here, we demonstrate that DIO2 expression increases in endometrium during the establishment of endometrial receptivity and is involved in this process. Iopanoic acid inhibition of DIO2 in vivo can cause a delayed receptive state. In vitro adhesion models have consistently confirmed that knocking down DIO2 in epithelial cells inhibited receptivity establishment. Membrane lipidomics was performed to explore how DIO2 regulates the morphological transformation of endometrial epithelial cells. We found that the deletion of Dio2 inhibited the increase in the degree of lipid unsaturation, which subsequently decreased membrane fluidity. Transcriptomics analysis was employed to explore the downstream target gene of T3-THR signaling mediated by Dio2-mediated T3-THR signaling, and Scd1 is confirmed as the direct target gene of THR in endometrial epithelial cells. These data reveal that DIO2 could regulate lipid metabolism by targeting Scd1 through the T3-THR signaling pathway, thereby modifying membrane fluidity of endometrial epithelial cells and promoting cell morphological transformation to establish endometrial receptivity. These findings contribute to filling the gap in downstream pathways activated by T3-THR signaling in endometrial cells and provide insights into the new therapeutics, prediagnosis, and preventive strategies for the derailment of endometrial receptivity and subsequently adverse "ripple effect" including infertility.

Methionine in embryonic development: metabolism, redox homeostasis, epigenetic modification and signaling pathway

Methionine, an essential sulfur-containing amino acid, plays a critical role in methyl metabolism, folate metabolism, polyamine synthesis, redox homeostasis maintenance, epigenetic modification and signaling pathway regulation, particularly during embryonic development. Animal and human studies have increasingly documented that methionine deficiency or excess can negatively impact metabolic processes, translation, epigenetics, and signaling pathways, with ultimate detrimental effects on pregnancy outcomes. However, the underlying mechanisms by which methionine precisely regulates epigenetic modifications and affects signaling pathways remain to be elucidated. In this review, we discuss methionine and the metabolism of its metabolites, the influence of folate-mediated carbon metabolism, redox reactions, DNA and RNA methylation, and histone modifications, as well as the mammalian rapamycin complex and silent information regulator 1-MYC signaling pathway. This review also summarizes our present understanding of the contribution of methionine to these processes, and current nutritional and pharmaceutical strategies for the prevention and treatment of developmental defects in embryos.

Understanding epigenetic regulation in the endometrium - lessons from mouse models with implantation defects

Endometrial function, crucial for successful embryo implantation, is significantly influenced by epigenetic regulation. This review investigates the crucial roles of DNA methylation, histone modifications, chromatin remodeling, and RNA methylation in endometrial receptivity and implantation, based on a survey of recent literature on knockout mouse models with implantation defects. These models illuminate how epigenetic disruptions contribute to implantation failure, a significant human reproductive health concern. DNA methylation and histone modifications modulate endometrial receptivity by affecting gene silencing and chromatin structure, respectively. Chromatin remodeling factors also play a critical role in endometrial dynamics, influencing gene expression. Furthermore, RNA methylation emerges as critical in implantation through transcriptional and translational control. While human studies provide limited epigenetic snapshots, mouse models with suppressed epigenetic regulators reveal direct causal links between epigenetic alterations and implantation failure. Understanding these epigenetic interactions offers potential for novel therapies addressing reproductive disorders.

Identification and expression profile analysis of circRNAs associated with goat uterus with different fecundity during estrous cycle

BACKGROUND

The Yunshang Black Goat, a distinguished meat goat breed native to China, is renowned for its superior reproductive capabilities. Despite this, there is considerable phenotypic variability within the breed. During the reproductive cycle, the uterus plays a pivotal role, with its functions evolving in line with the different stages of the cycle. This study focuses on the uterine tissues, including both the endometrium and myometrium, of Yunshang Black Goats with high fecundity (HF) and low fecundity (LF) during the proliferative (FP) and secretory (LP) phases of the estrous cycle. By examining these tissues, we aim to elucidate the underlying molecular and physiological mechanisms of the observed differences in reproductive success.

RESULTS

High-throughput sequencing was conducted, followed by bioinformatics analysis to identify the expression profiles of circRNAs. A total of 7,445 circRNAs were identified through the integration of findings from find_circ and CIRI2 software. Comparative analyses between the FPLF vs. FPHF and LPLF vs. LPHF revealed 149 differentially expressed (DE) circRNAs (94 up-regulated and 55 down-regulated) and 276 DE circRNAs (56 up-regulated and 220 down-regulated), respectively. The enrichment analysis indicated that the primary pathways involved were the Sphingolipid signaling pathway, MAPK signaling pathway, and GnRH signaling pathway, all of which are closely associated with cellular growth and development. Additionally, several key candidate genes were identified, such as FGF2 and MBTPS1. We also predicted a total of 281 miRNA-circRNA binding pairs, encompassing 263 circRNAs and 60 miRNAs, and simultaneously, 14 coding circRNAs were anticipated.

CONCLUSION

Based on the analysis, we have established the expression profiles of circRNAs during the follicular and luteal phases, respectively. Furthermore, using various analytical methods and data from high- and low-yield experimental control groups over different periods, we have identified multiple circRNAs that affect the high reproductive capacity of goats. Through enrichment analysis of the host genes of these circRNAs, we have discovered several key candidate genes. These findings provide fundamental data for the study of the molecular mechanisms underlying the fecundity of goats and pave the way for future genetic improvement strategies.

Association between the dietary index for gut microbiota and female infertility: The mediation effects of lymphocyte count and red blood cell folate

Previous studies have revealed a the relationship between changes in the gut microbiota composition and female infertility. While the association between the dietary index for gut microbiota (DI-GM) and female infertility remains unstudied. The correlation was investigated with NHANES data from 2013 to 2018, with dietary recall data being used to calculate the DI-GM. Mediation analysis was performed to explore the role of lymphocyte count (LC) and red blood cell (RBC) folate in the DI-GM-induced risk of female infertility risk. Among the 1555 individuals included in our study, 311 were diagnosed with female infertility. According to the weighted binary logistic regression analyses, when all the covariates were adjusted, a negative association was observed between the DI-GM score and the risk of female infertility (OR: 0.80, 95 %CI: 0.74-0.88). After grouping participants by DI-GM score, compared with scores in the lowest quartile (Q1), the scores in Q3 and Q4 of DI-GM score were negatively associated with female infertility in crude and adjusted models, with ORs (95 %CI; P for trend) of 0.44 (0.27-0.70; <0.001); 0.43 (0.28-0.64; <0.001) and 0.43(0.26-0.71; <0.001); 0.41(0.27-0.60; <0.001). Additionally, restricted cubic splines logistic analysis uncovered a nonlinear association between the DI-GM score and the prevalence of female infertility. Mediation analysis indicated that LC and RBC folate mediated 4.64 % and 7.08 %, respectively of the association of the DI-GM scores with risk of female infertility. The nomogram exhibited good performance in this study (AUC 0.70, 95 % CI = 0.67-0.73). Our research revealed that the DI-GM score was negatively related to risk of female infertility. Mediation analyses demonstrated that LC and RBC folate levels significantly mediate the association between the DI-GM and the prevalence of female infertility.

Potential role of Hematopoietic PBX-Interacting Protein (HPIP) in trophoblast fusion and invasion: Implications in pre-eclampsia pathogenesis

Pre-eclampsia is a known hypertensive disorder of pregnancy. While abnormal placentation and poor trophoblast invasion into maternal endometrium during blastocyst implantation are primary causes of pre-eclampsia, the underlying mechanisms remain elusive. Hematopoietic PBX-Interacting protein (HPIP) is an estrogen receptor (ER) interacting protein that plays a pivotal role in cell proliferation, migration, and differentiation; however, its role in trophoblast functions is largely unknown. In this study, we used BeWo cells as a model system to investigate trophoblast fusion and syncytialization, focusing on the role of HPIP in regulating these critical aspects of trophoblast functions. Herein, we report that HPIP expression declines during forskolin-induced trophoblast fusion in BeWo cells. In support of these observations, HPIP depletion enhanced forskolin-induced human chorionic gonadotropin-β (β-hCG), ERVWE1, and GCM1 expression, markers for trophoblast fusion. Furthermore, silencing of HPIP decreased cell invasion and epithelial to mesenchymal transition (EMT), a prerequisite for syncytialization in BeWo cells. Functional genomic studies further revealed a regulatory role for HPIP in a subset of gene networks involved in trophoblast fusion and EMT. We also uncovered that HPIP is a proteolytic substrate of furin, which is known to promote trophoblast cell fusion. Clinical data further indicated a significantly lower expression level of HPIP in pre-eclampsia subjects than in normal subjects. These findings imply that HPIP inhibits trophoblast fusion while promoting invasion and EMT, and its downregulation in trophoblasts might have implications for pre-eclampsia development.

The modeling of human implantation and early placentation: achievements and perspectives

BACKGROUND

Successful implantation is a critical step for embryo survival. The major losses in natural and assisted human reproduction appeared to occur during the peri-implantation period. Because of ethical constraints, the fascinating maternal-fetal crosstalk during human implantation is difficult to study and thus, the possibility for clinical intervention is still limited.

OBJECTIVE AND RATIONALE

This review highlights some features of human implantation as a unique, ineffective and difficult-to-model process and summarizes the pros and cons of the most used in vivo, ex vivo and in vitro models. We point out the variety of cell line-derived models and how these data are corroborated by well-defined primary cells of the same nature. Important aspects related to the handling, standardization, validation, and modus operandi of the advanced 3D in vitro models are widely discussed. Special attention is paid to blastocyst-like models recapitulating the hybrid phenotype and HLA profile of extravillous trophoblasts, which are a unique yet poorly understood population with a major role in the successful implantation and immune mother-embryo recognition. Despite raising new ethical dilemmas, extended embryo cultures and synthetic embryo models are also in the scope of our review.

SEARCH METHODS

We searched the electronic database PubMed from inception until March 2024 by using a multi-stage search strategy of MeSH terms and keywords. In addition, we conducted a forward and backward reference search of authors mentioned in selected articles.

OUTCOMES

Primates and rodents are valuable in vivo models for human implantation research. However, the deep interstitial, glandular, and endovascular invasion accompanied by a range of human-specific factors responsible for the survival of the fetus determines the uniqueness of the human implantation and limits the cross-species extrapolation of the data. The ex vivo models are short-term cultures, not relevant to the period of implantation, and difficult to standardize. Moreover, the access to tissues from elective terminations of pregnancy raises ethical and legal concerns. Easy-to-culture cancer cell lines have many limitations such as being prone to spontaneous transformation and lacking decent tissue characteristics. The replacement of the original human explants, primary cells or cancer cell lines with cultures of immortalized cell lines with preserved stem cell characteristics appears to be superior for in vitro modeling of human implantation and early placentation. Remarkable advances in our understanding of the peri-implantation stages have also been made by advanced three dimensional (3D) models i.e. spheroids, organoids, and assembloids, as placental and endometrial surrogates. Much work remains to be done for the optimization and standardization of these integrated and complex models. The inclusion of immune components in these models would be an asset to delineate mechanisms of immune tolerance. Stem cell-based embryo-like models and surplus IVF embryos for research bring intriguing possibilities and are thought to be the trend for the next decade for in vitro modeling of human implantation and early embryogenesis. Along with this research, new ethical dilemmas such as the moral status of the human embryo and the potential exploitation of women consenting to donate their spare embryos have emerged. The careful appraisal and development of national legal and ethical frameworks are crucial for better regulation of studies using human embryos and embryoids to reach the potential benefits for human reproduction.

WIDER IMPLICATIONS

We believe that our data provide a systematization of the available information on the modeling of human implantation and early placentation and will facilitate further research in this field. A strict classification of the advanced 3D models with their pros, cons, applicability, and availability would help improve the research quality to provide reliable outputs.

Sialidases derived from Gardnerella vaginalis remodel the sperm glycocalyx and impair sperm function

Bacterial vaginosis (BV), a dysbiosis of the vaginal microbiome, affects approximately 29 percent of women worldwide (up to 50% in some regions) and is associated with several adverse health outcomes including preterm birth and increased incidence of sexually transmitted infection (STI). BV-associated bacteria, such as Gardnerella vaginalis and Prevotella timonensis, damage the vaginal mucosa through the activity of sialidase enzymes that remodel the epithelial glycocalyx and degrade mucin glycoproteins. This damage creates an inflammatory environment which likely contributes to adverse health outcomes. However, whether BV-associated glycolytic enzymes also damage sperm during their transit through the reproductive tract has not yet been determined. Here, we show that sialidase-mediated glycocalyx remodeling of human sperm increases sperm susceptibility to damage within the female reproductive tract. In particular, we report that desialylated human sperm demonstrate increased susceptibility to complement lysis and agglutination, as well as decreased sperm transit through cervical mucus. Our results demonstrate a mechanism by which BV-associated sialidases may affect sperm survival and function and potentially contribute to adverse reproductive outcomes such as preterm birth and infertility.

Gestational Diabetes Mellitus: Mechanisms Underlying Maternal and Fetal Complications

Gestational diabetes mellitus (GDM) affects over 10% of all pregnancies, both in Korea and worldwide. GDM not only increases the risk of adverse pregnancy outcomes such as preeclampsia, preterm birth, macrosomia, neonatal hypoglycemia, and shoulder dystocia, but it also significantly increases the risk of developing postpartum type 2 diabetes mellitus and cardiovascular disease in the mother. Additionally, GDM is linked to a higher risk of childhood obesity and diabetes in offspring, as well as neurodevelopmental disorders, including autistic spectrum disorder. This review offers a comprehensive summary of clinical epidemiological studies concerning maternal and fetal complications and explores mechanistic investigations that reveal the underlying pathophysiology.

Multi-modality imaging technologies and machine learning for non-invasive, precise assessment of rabbit endometrium

Developing a minimally invasive, real-time diagnostic tool to accurately assess endometrial conditions is critical to increasing pregnancy rates in assisted reproductive technology (ART). In this research, fiberoptic bronchoscopy and optical coherence tomography (OCT) were used before and after alcohol injury and human chorionic gonadotropin (hCG)-induced pseudopregnancy to monitor changes in the rabbit endometrium. Histological analysis and electron microscopy were performed on 1 cm uterine sections while simultaneously training a conditional generative adversarial network (cGAN) to convert OCT images into virtual hematoxylin and eosin H&E stained sections. By combining these optical elements, we have managed to non-invasively observe changes in the endometrium at different stages. Traditional endoscopy assesses surface changes such as mucosal color changes, congestion, and fibrous adhesions, while OCT provides detailed views of superficial and submucosal changes and can correspond to pathological H&E sections. Machine learning improves OCT by converting images to H&E format, enabling real-time, non-invasive assessment of endometrial status and improving the accuracy of endometrial receptivity assessment.

Dan'e fukang decoction reduces hemorrhage in a rat model of mifepristone induced incomplete abortion and may correlate with cell adhesion molecule signaling interference

ETHNOPHARMACOLOGICAL RELEVANCE

Dan'e fukang decoction (DFD) is a traditional Chinese medicine formula. DFD obtains 10 herbs, including Salvia yunnanensis C.H.Wright (Zidanshen), Curcuma zedoaria (Christm.) Roscoe (Ezhu), Angelica sinensis (Oliv.) Diels (Danggui), Cyperus rotundus L. (Xiangfuzi), Corydalis yanhusuo (Y.H.Chou & Chun C. Hsu) W.T.Wang ex Z.Y.Su & C.Y.Wu, Bupleurum marginatum Wall. ex DC. (Yanhusuo), Sparganium stoloniferum (Buch.-Ham. ex Graebn.) Buch.-Ham. ex Juz. (Sanleng), Panax notoginseng (Burkill) F.H.Chen (Sanqi), Paeonia lactiflora Pall. (Shaoyao) and Glycyrrhiza uralensis Fisch. (Gancao). DFD is now clinically used for the treatment of menstrual irregularities, dysmenorrhea and menstrual discomfort caused by blood stasis and easing of endometriosis. Based on this, it is reasonable to presume that DFD may be effective in treating incomplete abortion and reducing postpartum bleeding, but no specific studies have been reported so far.

AIM OF THE STUDY

To investigate the efficacy of Dan'e fukang decoction (DFD) in reducing prolonged vaginal bleeding followed by mifepristone induced incomplete abortion and explore the mechanisms of action of DFD in treating incomplete abortion.

METHODS

An incomplete abortion model of rat was established by single intragastrically administered 8.5 mg/kg mifepristone on the 7th day of pregnancy. From the 8th day of pregnancy, the abortive rats were administered solvent, a positive control drug, or different doses of DFD, respectively for seven consecutive days. The efficacy of DFD was assessed by measuring the vaginal bleeding volume of the rats. Four coagulation parameters and platelet counts were measured. Hematoxylin and eosin (HE) staining was performed to evaluate pathological changes in the uterine embryos. Serum levels of progesterone and estrogen were measured using ELISA. Network pharmacology and transcriptomics were used to predict potential targets and pathways for DFD to reduce hemorrhage. The levels of mRNA related to cell adhesion molecules (CAMs) were detected by RT-qPCR. The levels of progesterone and estrogen receptors and the proteins associated with CAMs pathway in uterine tissues were detected by Western Blot.

RESULTS

DFD significantly reduced the volume of vaginal bleeding of the abortive rats and significantly downgraded the pathological scores of uterine embryos. DFD significantly increased serum levels of E2, and had no impact on serum levels of P4 and the protein expression of ER and PR in the uteri of the abortive rats. Pathways in cancer, lipid, focal adhesion and immune-related signaling were predicted to be influenced by DFD via the analysis of network pharmacology. The CAMs signaling was found the most critical pathway regulated by both mifepristone and DFD via RNA-seq assay, followed by axon guidance, basal cell carcinoma, hippo signaling pathway and neuroactive ligand-receptor interaction. Combining the two analytical methods, ICAM-1 was predicted likely the key targeted gene by DFD. Finally, DFD was validated to decrease the protein expression of ICAM-1, ITGB2, ITGB7 and RASSF5 in the uterine tissues, which correlated to suppress the CAMs signaling pathway.

CONCLUSION

DFD significantly reduced hemorrhage. DFD significantly increased the serum levels of E2 and inhibited CAMs signaling pathway, which was likely to be involved in the mechanism of action of DFD facilitating residual uterine embryo expulsion in the rat model of incomplete abortion.

Mechanism of hsa_circ_0069443 promoting early pregnancy loss through ALKBH5/FN1 axis in trophoblast cells

Studies have shown that circRNAs play an important regulatory role in trophoblast function and embryonic development. Based on sequencing and functional experiments, we found that hsa_circ_0069443 can regulate the function of trophoblast cells, and its presence is found in the exosomes secreted by trophoblast cells. It is known that exosomes mediate the interaction between the uterus and embryo, which is crucial for successful pregnancy. We found that trophoblast cell-derived exosomes overexpressing hsa_circ_0069443 promoted the migration and invasion of endometrial stromal cells as well as the EMT process of endometrial glandular epithelial cells, and this process promotes embryo implantation and adhesion, thus proving that a decrease in hsa_circ_0069443 may be the key factor leading to early pregnancy loss. This study also found that hsa_circ_0069443 can bind to the RNA-binding protein demethylase ALKBH5, affecting the overall m6A level of trophoblast cells, and hsa_circ_0069443 and ALKBH5 can regulate the expression level of FN1, verifying the role of the 0069443/ALKBH5/FN1 axis in trophoblast cells and endometrial stromal cells. In summary, this study demonstrates that hsa_circ_0069443 may be a key factor leading to early pregnancy loss, and the regulation of the hsa_circ_0069443/ALKBH5/FN1 axis may provide new insights into early diagnostic markers for early pregnancy loss.

Tire rubber-derived contaminants 6PPD and 6PPD-quinone reduce attachment and outgrowth of trophoblast spheroids onto endometrial epithelial cells

N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), a synthetic additive widely used in the rubber industry, and its oxidized product 6PPD-quinone (6PPDQ), have garnered widespread attention as an emerging hazardous chemicals owing to their potential detrimental effects on aquatic ecosystem and human health. The effects of 6PPD and 6PPDq on the female reproductive tract, especially embryo implantation, remain unknown and were investigated in this study. We used the spheroid attachment and outgrowth models of BeWo trophoblastic spheroids and Ishikawa cells as surrogates for the human blastocyst and endometrial epithelium, respectively. Treatment with the chemicals for up to 48 h decreased the viability of the cells in a dose- and cell line-dependent manner (20-100 μM 6PPD and 10-100 μM 6PPDQ for both the cell lines). At a noncytotoxic concentration, exposure of Ishikawa cells to 1 and 10 μM 6PPD reduced the attachment of BeWo spheroids and further inhibited their invasion and outgrowth on the endometrial epithelial monolayer. A similar result was observed in 1 μM 6PPDQ-exposed groups. Gene expression profiling of 6PPD- and 6PPDQ-exposed endometrial epithelial cells revealed that both 6PPD and 6PPDQ differentially regulated a panel of transcript markers toward overall downregulation of receptivity and invasion. The study provides the first proof of the adverse effects of 6PPD and 6PPDQ on human endometrial receptivity and trophoblast invasion during the window of implantation, warranting the need for further in vivo and clinical studies.

Endometrial Receptivity-Lessons from "Omics"

The window of implantation (WOI) is a critical phase of the menstrual cycle during which the endometrial lining becomes receptive and facilitates embryo implantation. Drawing on findings from various branches of "omics", including genomics, epigenomics, transcriptomics, proteomics, lipidomics, metabolomics, and microbiomics, this narrative review aims to (1) discuss mechanistic insights on endometrial receptivity and its implication in infertility; (2) highlight advances in investigations for endometrial receptivity; and (3) discuss novel diagnostic and therapeutic strategies that may improve reproductive outcomes.

Developmental exposure to perfluorooctane sulfonate(PFOS) impairs the endometrial receptivity

Perfluorooctane sulfonate (PFOS) is a widely used chemical in industrial production. It can be introduced into the environment through multiple pathways and exhibits resistance to degradation. Recent research has demonstrated a significant correlation between its exposure levels in the human body and the incidence of various diseases. The expression of genes related to endometrial receptivity and the differentiation of human endometrial stromal cells (hESCs) were assessed in this study concerning PFOS. In this study, we investigated the effect of PFOS exposure on endometrial tolerance by cell and animal experiments. The activity against endometrial mesenchymal cells was significantly reduced by PFOS intervention, and the apoptosis flow assay results showed that PFOS significantly promoted cell death in a concentration-dependent manner. Transmission electron microscopy results revealed mitochondrial damage in the PFOS-intervened group, and WB results showed that the expression levels of endometrial tolerance-related proteins Homeobox A10 (HOXA10) and integrin beta3 (ITGB3) were decreased, and the expression level of Forkhead box O1 (FOXO1) protein was increased. Animal studies have shown that PFOS exposure can change uterine morphology, cause obvious damage to pinopodes morphology, change the estrous cycle of mice, and affect endometrial receptivity In the present study, we found that PFOS may synergistically affect the viability of endometrial mesenchymal stromal cells through accumulation in vivo, and that PFOS may contribute to the failure of embryo implantation by affecting mitochondrial function and consequently endometrial permissive sites.

Endometrial extracellular vesicles regulate processes related to embryo development and implantation in human blastocysts

STUDY QUESTION

What is the transcriptomic response of human blastocysts following internalization of extracellular vesicles (EVs) secreted by the human endometrium?

SUMMARY ANSWER

EVs secreted by the maternal endometrium induce a transcriptomic response in human embryos that modulates molecular mechanisms related to embryo development and implantation.

WHAT IS KNOWN ALREADY

EVs mediate intercellular communication by transporting various molecules, and endometrial EVs have been postulated to be involved in the molecular regulation of embryo implantation. Our previous studies showed that endometrial EVs carry miRNAs and proteins associated with implantation events that can be taken up by human blastocysts; however, no studies have yet investigated the transcriptomic response of human embryos to this EV uptake, which is crucial to demonstrate the functional significance of this communication system.

STUDY DESIGN, SIZE, DURATION

A prospective descriptive study was performed. Primary human endometrial epithelial cells (pHEECs), derived from endometrial biopsies collected from fertile oocyte donors (n = 20), were cultured in vitro to isolate secreted EVs. Following EV characterization, Day 5 human blastocysts (n = 24) were cultured in the presence or absence of the EVs for 24 h and evaluated by RNA-sequencing.

PARTICIPANTS/MATERIALS, SETTING, METHODS

EVs were isolated from the conditioned culture media using ultracentrifugation, and characterization was performed using western blot, nanoparticle tracking analysis, and transmission electron microscopy. Human blastocysts were devitrified, divided into two groups (n = 12/group), and cultured in vitro for 24 h with or without previously isolated EVs. RNA-sequencing analysis was performed, and DESeq2 was used to identify differentially expressed genes (DEGs) (FDR < 0.05). QIAGEN Ingenuity Pathway Analysis was used to perform the functional enrichment analysis and integration with our recently published data from the pHEECs' EV-miRNA cargo.

MAIN RESULTS AND THE ROLE OF CHANCE

Characterization confirmed the isolation of EVs from pHEECs' conditioned culture media. Among the DEGs in blastocysts co-cultured with EVs, we found 519 were significantly upregulated and 395 were significantly downregulated. These DEGs were significantly enriched in upregulated functions related to embryonic development, cellular invasion and migration, cell cycle, cellular organization and assembly, gene expression, and cell viability; and downregulated functions related to cell death and DNA fragmentation. Further, the intracellular signaling pathways regulated by the internalization of endometrial EVs were previously related to early embryo development and implantation potential, for their role in pluripotency, cellular homeostasis, early embryogenesis, and implantation-related processes. Finally, integrating data from miRNA cargo of EVs, we found that the miRNAs carried by endometrial EVs targeted nearly 80% of the DEGs in human blastocysts.

LIMITATIONS, REASONS FOR CAUTION

This is an in vitro study in which conditions of endometrial cell culture could not mimic the intrauterine environment.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides novel insights into the functional relevance of EVs secreted by the human endometrium, and particularly the role of EV-miRNA regulation on global transcriptome behavior of human blastocysts during early embryogenesis and embryo implantation. It provides potential biomarkers that could become useful diagnostic targets for predicting implantation success.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Spanish Ministry of Education through FPU awarded to M.S.-B. (FPU18/03735), Generalitat Valenciana through VALi+d Programme awarded to M.C.C.-G. (ACIF/2019/139), and Instituto de Salud Carlos III and cofounded by the European Social Fund (ESF) "Investing in your future" through the Miguel Servet Program (CP20/00120 [H.F.]; CP19/00149 [I.C.]). The authors have no conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Endocrine Diagnostics: Principles and Applications

Endocrine diagnostics currently depend on the ability to measure low and high concentrations of diagnostic hormones using immunoassays. This often is challenging in species other than humans, dogs, cats, and horses due to lack of validated assays and reference intervals. There are strategies to approach endocrine testing in zoo, wildlife, and zoologic companion animals but caution is needed in interpreting results. Newer techniques such as liquid chromatography-tandem mass spectrometry (LC-MS/MS) may be more useful for all species, although technical hurdles remain for this method too.

Assessing the Impact of Exposure Misclassification in Case-Control Studies of Self-Reported Medication Use

BACKGROUND

Empirically evaluating the potential impact of recall bias on observed associations of prenatal medication exposure is crucial.

OBJECTIVE

We sought to assess the effects of exposure misclassification on previous studies of the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in early pregnancy and increased risk of amniotic band syndrome (ABS).

METHODS

Using data from the National Birth Defects Prevention Study (NBDPS) on births from 1997 to 2011, we included 189 mothers of infants with ABS and 11,829 mothers of infants without congenital anomalies. We identified external studies of medication use during pregnancy to obtain validity parameters for a probabilistic bias analysis to adjust for exposure misclassification. Due to uncertainty about the transportability of these parameters, we conducted multidimensional bias analyses to explore combinations of values on the results.

RESULTS

When we assumed higher specificity in cases or higher sensitivity in controls, misclassification-adjusted estimates suggested confounding-adjusted estimates were attenuated. However, in a few instances, when we assumed greater sensitivity in the cases than the controls (and Sp ≥ 0.9), the misclassification-adjusted estimates suggested upward bias in the confounding-adjusted estimates.

CONCLUSIONS

Results from our bias analysis highlighted that the magnitude of bias depended on the mechanism and the extent of misclassification. However, the parameters available from the validation studies were not directly applicable to our study. In the absence of reliable validation studies, considering mechanisms of bias and simulation studies to outline combinations of plausible scenarios to better inform conclusions on the effects of these medications on pregnancy outcomes remains important.

Receptive window might be shorter in patients with endometriosis and lesions cyclically prepare for implantation

OBJECTIVE

To investigate whether endometrial receptivity is affected in patients with endometriosis using podocalyxin (PCX) as a functional biomarker and to study how endometriotic lesions display PCX and the potential pathological implications.

DESIGN

We have previously reported that PCX, an anti-adhesion glycoprotein and barrier protector, is dynamically regulated in the endometrium and acts as a key negative regulator of epithelial receptivity. Early in the cycle both luminal epithelium (LE, lining the endometrial surface) and glandular epithelium (GE, residing within the tissue) strongly express PCX, but in the receptive window, PCX is selectively downregulated in LE, switching the endometrial surface to an adhesive state for embryo attachment/implantation; meanwhile, PCX expression is maintained in GE until postreceptivity. Here, we immuno-stained PCX in endometrial tissues and ectopic lesions biopsied across the menstrual cycle from patients with endometriosis (EOS, n = 41), and compared with endometrium of non-endometriosis controls (non-EOS, n = 55). We further investigated how PCX changes observed in ectopic lesions may influence their adhesive capacity.

SETTING

RMIT University, Australia.

PATIENTS

Women without and with endometriosis.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURES

The window of endometrial receptivity might be shorter in patients with endometriosis; ectopic sites in addition downregulate PCX cyclically, mirroring the eutopic endometrial cells in preparing for receptivity to increase their adhesion potential.

RESULTS

Endometrial PCX levels were comparable between non-EOS and EOS early in the cycle, and in both groups, PCX is downregulated in LE during the expected window of receptivity; however, in EOS endometrium, PCX is reduced earlier in GE as if the receptive window were shorter. In endometriotic lesions, PCX was detected in endometrial LE- and GE-like cells plus mesothelial cells enveloping peritoneal organs, but PCX was cyclically lost specifically in LE-like cells and reduced in GE-like cells as seen in the eutopic endometrium, which however may increase their adhesion potential to nearby organs (overlaid by mesothelial cells). This speculation was further corroborated in an in vitro model showing endometrial epithelial cells with lower PCX were indeed more adhesive to mesothelial cells.

CONCLUSION

Endometrial receptivity is subtly affected in patients with endometriosis with a shorter window. Cyclic downregulation of PCX in ectopic sites may have pathological consequences.

The TCONS_00046732/chi-miR-135b-5p/PRLR regulatory axis promotes endometrial epithelial cells growth through the PI3K-Akt signaling pathway

Non-coding RNAs are considered key regulatory factors in biological and reproductive physiological processes in mammals. However, the molecular functions of long noncoding RNAs (lncRNAs) in regulating dynamic uterine development and reproductive capacity during sexual maturation remain unclear. This study analyzed the expression characteristics and molecular functions of lncRNAs in uterine tissues from 20 goats at four specific time points during sexual maturation: day 1 after birth (D1), 2 months (M2), 4 months (M4), and 6 months (M6), finding that stage-specific DE lncRNAs may regulate cell proliferation, apoptosis, hormone secretion, metabolism, and immune response through multiple action modes. Within the lncRNA-miRNA-mRNA network, a novel lncRNA, TCONS_00046732, associated with uterine development, exhibited significantly higher expression during sexual maturity compared to the prepubertal stage, correlating positively with PRLR and negatively with chi-miR-135b-5p. FISH and IF analyses revealed significant co-localization and distinct expression patterns of TCONS_00046732, chi-miR-135b-5p, and PRLR in the endometrial epithelium. Further experiments confirmed that TCONS_00046732 competitively binds to chi-miR-135b-5p to upregulate PRLR, thereby activating the PI3K-Akt signaling pathway, promoting primary endometrial epithelial cell proliferation, G1-to-S phase transition, and inhibiting apoptosis. These findings enhance our understanding of uterine molecular regulation and provide key insights into the molecular basis of goat sexual development.

Chenodeoxycholic acid fortified diet drives ovarian steroidogenesis to improve embryo implantation through enhancing uterine receptivity via progesterone receptor signaling pathway in rats

Infertility is a worldwide reproductive health problem influenced by the embryo implantation efficiency. We previously revealed that dietary chenodeoxycholic acid (CDCA) positively influence the early embryo implantation. But how CDCA regulate embryo implantation is largely unexplored. Herein, we investigated the mechanism behind CDCA's regulation on embryo implantation in rats. Results showed that CDCA promoted uterine receptivity, leading to increased number of implantation sites. Mechanistically, CDCA reshaped maternal amino acid metabolism and enhanced serum progesterone levels. CDCA enhanced ovarian progesterone synthesis by improving steroidogenesis-related protein (StAR and CYP11A1) expression via Takeda G-protein-coupled receptor 5. Elevated progesterone exaggerated uterine progesterone but weakened the estradiol signaling in the CDCA group, contributing to better uterine receptive for embryo implantation. Additionally, elevated transcription repressor Stat5b induced the down-regulation of progesterone-metabolizing enzyme 20-hydroxysteroid dehydrogenase 20α-HSD, complementally explained uterine progesterone signaling enhancement. Overall, our data revealed that CDCA drove ovarian steroidogenesis to improve embryo implantation through enhancing uterine receptivity via progesterone receptor pathway in rats. Therefore, CDCA diet may be a potential favorable nutritional strategy for infertility and pregnancy management.

Single-cell RNA sequencing reveals heterogeneity and differential expression of the maternal-fetal interface during ICP and normal pregnancy

OBJECTIVE

Intrahepatic cholestasis of pregnancy (ICP) can cause adverse perinatal outcomes. Previous studies have demonstrated that the placenta of an ICP pregnancy differs in morphology and gene expression from the placenta of a normal pregnancy. To date, however, the genetic mechanism by which ICP affects the placenta is poorly understood. Therefore, the aim of this study was to investigate the differences in main cell types, gene signatures, cell ratio, and functional changes in the placenta between ICP and normal pregnancy.

METHODS

Single-cell RNA sequencing (scRNA-seq) technology was used to detect the gene expression of all cells at the placental maternal-fetal interface. Two individuals were analyzed - one with ICP and one without ICP. The classification of cell types was determined by a graph-based clustering algorithm. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the R software phyper () function and DAVID website. The differentially expressed genes (DEGs) encoding transcription factors (TFs) were identified using getorf and DIAMOND software.

RESULTS

We identified 14 cell types and 22 distinct cell subtypes that showed unique functional properties. Additionally, we found differences in the proportions of fibroblasts 1, helper T (Th) cells, extravillous trophoblasts, and villous cytotrophoblasts, and we observed heterogeneity of gene expression between ICP and control placentas. Furthermore, we identified 263 DEGs that belonged to TF families, including zf-C2H2, HMGI/HMGY, and Homeobox. In addition, 28 imprinted genes were preferentially expressed in specific cell types, such as PEG3 and PEG10 in trophoblasts as well as DLK1 and DIO3 in fibroblasts.

CONCLUSIONS

Our results revealed the differences in cell-type ratios, gene expression, and functional changes between ICP and normal placentas, and heterogeneity was found among cell subgroups. Hence, the imbalance of various cell types affects placental activity to varying degrees, indicating the complexity of the cell networks that form the placental tissue system, and this alteration of placental function is associated with adverse events in the perinatal period.

Role of miRNAs in assisted reproductive technology

Cellular proteins and the mRNAs that encode them are key factors in oocyte and sperm development, and the mechanisms that regulate their translation and degradation play an important role during early embryogenesis. There is abundant evidence that expression of microRNAs (miRNAs) is crucial for embryo development and are highly involved in regulating translation during oocyte and early embryo development. MiRNAs are a group of short (18-24 nucleotides) non-coding RNA molecules that regulate post-transcriptional gene silencing. The miRNAs are secreted outside the cell by embryos during preimplantation embryo development. Understanding regulatory mechanisms involving miRNAs during gametogenesis and embryogenesis will provide insights into molecular pathways active during gamete formation and early embryo development. This review summarizes recent findings regarding multiple roles of miRNAs in molecular signaling, plus their transport during gametogenesis and embryo preimplantation.

Beyond 2D: Novel biomaterial approaches for modeling the placenta

This review considers fully three-dimensional biomaterial environments of varying complexity as these pertain to research on the placenta. The developments in placental cell sources are first considered, along with the corresponding maternal cells with which the trophoblast interact. We consider biomaterial sources, including hybrid and composite biomaterials. Properties and characterization of biomaterials are discussed in the context of material design for specific placental applications. The development of increasingly complicated three-dimensional structures includes examples of advanced fabrication methods such as microfluidic device fabrication and 3D bioprinting, as utilized in a placenta context. The review finishes with a discussion of the potential for in vitro, three-dimensional placenta research to address health disparities and sexual dimorphism, especially in light of the exciting recent changes in the regulatory environment for in vitro devices.

Embryo-Derived Cathepsin B Promotes Implantation and Decidualization by Activating Pyroptosis

Embryo implantation and decidualization are crucial for a successful pregnancy. How the inflammatory response is regulated during these processes is undefined. Pyroptosis is an inflammatory form of cell death mediated by gasdermin D (GSDMD). Through in vivo, cultured epithelial cells and organoids, it is shown that pyroptosis occurs in epithelial cells at the implantation site. Compared with those on day 4 of pseudopregnancy and delayed implantation, pyroptosis-related protein levels are significantly increased on day 4 of pregnancy and activated implantation, suggesting that blastocysts are involved in regulating pyroptosis. Blastocyst-derived cathepsin B (CTSB) is stimulated by preimplantation estradiol-17β and induces pyroptosis in epithelial cells. Pyroptosis-induced IL-18 secretion from epithelial cells activates a disintegrin and metalloprotease 12 (ADAM12) to process the epiregulin precursor into mature epiregulin. Epiregulin (EREG) enhances in vitro decidualization in mice. Pyroptosis-related proteins are detected in the mid-secretory human endometrium and are elevated in the recurrent implantation failure endometrium. Lipopolysaccharide treatment in pregnant mice causes implantation failure and increases pyroptosis-related protein levels. Therefore, the data suggest that modest pyroptosis is beneficial for embryo implantation and decidualization. Excessive pyroptosis can be harmful and lead to pregnancy failure.

Spatial and molecular anatomy of the endometrium during embryo implantation: a current overview of key regulators of blastocyst invasion

Embryo implantation is composed of three steps: blastocyst apposition, adhesion/attachment and invasion. Blastocyst invasion has been studied less extensively than the other two events. Historically, studies conducted using electron microscopy have shown the removal of epithelial cells in the vicinity of the attached blastocysts in rodents, although the underlying mechanisms have remained unclear. Here, we describe recent studies using mice with uterine-specific gene deletion that demonstrated important roles for nuclear proteins such as progesterone receptor, hypoxia inducible factor and retinoblastoma in the regulation of embryo invasion. In these mouse models, the detachment of the endometrial luminal epithelium, decidualization in the stroma, and the activation of trophoblasts have been found to be important in ensuring embryo invasion. This review summarizes the molecular signaling associated with these cellular events, mainly evidenced by mouse models.

The Role of the Endometrium in Implantation: A Modern View

According to the current data, the endometrium acts as a "sensor" of embryo quality, which promotes the implantation of euploid embryos and prevents the implantation and/or subsequent development of genetically abnormal embryos. The present review addresses the nature of the "sensory function" of the endometrium and highlights the necessity for assessing its functional status. The first section examines the evolutionary origin of the "sensory" ability of the endometrium as a consequence of spontaneous decidualization that occurred in placental animals. The second section details the mechanisms for implementing this function at the cellular level. In particular, the recent findings of the appearance of different cell subpopulations during decidualization are described, and their role in implantation is discussed. The pathological consequences of an imbalance among these subpopulations are also discussed. Finally, the third section summarizes information on currently available clinical tools to assess endometrial functional status. The advantages and disadvantages of the approaches are emphasized, and possible options for developing more advanced technologies for assessing the "sensory" function of the endometrium are proposed.

Decidualized Endometrial Stromal Cells Promote Mitochondrial Beta-Oxidation to Produce the Octanoic Acid Required for Implantation

Decidualization denotes the morphological and biological differentiating process of human endometrial stromal cells (HESCs). Fatty acid pathways are critical for endometrial decidualization. However, the participation of fatty acids as an energy source and their role in endometrial decidualization have received little attention. To identify fatty acids and clarify their role in decidualization, we comprehensively evaluated free fatty acid profiles using liquid chromatography/Fourier transform mass spectrometry (LC/FT-MS). LC/FT-MS analysis detected 26 kinds of fatty acids in the culture medium of decidualized or un-decidualized HESCs. Only the production of octanoic acid, which is an essential energy source for embryonic development, was increased upon decidualization. The expressions of genes related to octanoic acid metabolism including ACADL, ACADM, and ACADS; genes encoding proteins catalyzing the first step of mitochondrial fatty acid beta-oxidation; and ACSL5 and ACSM5; genes encoding fatty acid synthesis proteins were significantly altered upon decidualization. These results suggest that decidualization promotes lipid metabolism, implying that decidualized HESCs require energy metabolism of the mitochondria in embryo implantation.

Association between endometrial thickness and birthweight of singletons from vitrified-warmed cycles: a retrospective cohort study

RESEARCH QUESTION

What is the association between endometrial thickness (EMT) and the birthweight of singleton infants born from frozen-thawed embryo transfer cycles?

DESIGN

This retrospective cohort study was conducted from January 2016 to December 2019. Participants were categorized into a natural cycle (NC, n = 8132) group and hormone replacement therapy (HRT, n = 4975) group. Only singleton deliveries were included. The primary outcomes were measures of birthweight and relevant indexes. Multivariable logistic regression and multivariable-adjusted linear regression models that incorporated restricted cubic splines were used.

RESULTS

In the HRT group, the risk of delivering a small for gestational age (SGA) infant was increased in women with an EMT <8.0 mm (adjusted odds ratio [aOR] 1.85, 95% confidence interval [CI] 1.17-2.91) compared with women with an EMT of 8.0 to <12.0 mm, and increased with an EMT ≥12.0 mm (aOR 1.85, 95% CI 1.03-3.33). An inverted U-shaped relationship was found between EMT and birthweight in women with HRT. No significant differences were shown in birthweight z-score, or being SGA or large for gestational age, in singletons among the three EMT groups in the natural cycles.

CONCLUSIONS

A thinner endometrium seen in women undergoing HRT cycles was associated with a lower birthweight z-score, as well as a higher risk of SGA. However, no significant association was observed between EMT and birthweight z-score or SGA in the NC group. It is noteworthy that a thicker endometrium was not associated with a higher birthweight in frozen-thawed embryo transfer (FET) cycles. Women with a thin endometrium who achieve pregnancy require specialized attention, particularly if they are undergoing FET with HRT cycles.

The Extracts from Two Antarctic Fish Species, Trematomus newnesi and Trematomus bernacchii, Enhance JEG-3 Cell Migration and Invasion via MMP9 Activation Through Akt/Protein Phosphatase1/β-Catenin Pathway

SCOPE

This study investigates the impact of extracts derived from Antarctic fish species, Trematomus newnesi and Trematomus bernacchii, on the migration of human placental trophoblast JEG-3 cells, which is a crucial aspect of successful pregnancy.

METHODS AND RESULTS

The extracts, obtained from the muscles of these fish, significantly enhance the migration and invasion of JEG-3 cells in in vitro wound healing, Transwell, and collagen invasion assays. These effects are accompanied by an increase in matrix metalloproteinase (MMP) 9 activity, as demonstrated by zymography. Furthermore, the extracts activated Akt and protein phosphatase 1, resulting in the dephosphorylation of β-catenin at Ser33/37/Thr41, as confirmed by western blot analysis. Consequently, MMP9 is upregulated, while metallopeptidase inhibitor 1/3 is downregulated, as verified by western blot and qRT-PCR analyses. Finally, utilizing ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis, followed by matching with the Global Natural Product Social Molecular Networking library, the study annotates the compound responsible for the observed migratory activity as taurocholic acid. Importantly, the study confirms that taurocholic acid enhances cell migration in JEG-3 cells.

CONCLUSION

The results of this study emphasize the potential of Antarctic fish extracts in promoting extravillous trophoblast migration and invasion, which are critical for successful pregnancy.

Evolutionary Patterns of Maternal Recognition of Pregnancy and Implantation in Eutherian Mammals

The implantation of the embryo into the maternal endometrium is a complex process associated with the evolution of viviparity and placentation in mammals. In this review, we provide an overview of maternal recognition of pregnancy signals and implantation modes in eutherians, focusing on their diverse mechanisms and evolutionary patterns. Different pregnancy recognition signals and implantation modes have evolved in eutherian mammals, reflecting the remarkable diversity of specializations in mammals following the evolution of viviparity. Superficial implantation is the ancestral implantation mode in Eutheria and its major clades. The other modes, secondary, partially, and primary interstitial implantation have each independently evolved multiple times in the evolutionary history of eutherians. Although significant progress has been made in understanding pregnancy recognition signals and implantation modes, there is still much to uncover. Rodents and chiropterans (especially Phyllostomidae) offer valuable opportunities for studying the transitions among implantation modes, but data is still scarce for these diverse orders. Further research should focus on unstudied taxa so we can establish robust patterns of evolutionary changes in pregnancy recognition signaling and implantation modes.

Precise hourly personalized embryo transfer significantly improves clinical outcomes in patients with repeated implantation failure

Purpose

This study investigated whether RNA-Seq-based endometrial receptivity test (rsERT)-which provides precision for the optimal hour of the window of implantation (WOI)-can improve clinical outcomes of frozen embryo transfer (FET) cycles in patients with a history of repeated implantation failure (RIF).

Methods

Patients with a history of RIF who received at least one autologous high-quality blastocyst during the subsequent FET cycle were retrospectively enrolled and divided into two groups: rsERT and FET, comprising patients who underwent rsERT-guided pET (n=115) and standard FET without rsERT (n=272), respectively.

Results

In the rsERT group, 39.1% (45/115) of patients were receptive. rsERT patients showed a higher probability of achieving both positive human chorionic gonadotropin (63.5% vs. 51.5%, P=0.03) and clinical pregnancy (54.8% vs. 38.6%, P=0.003) rates. In subgroup analysis, rsERT patients with non-receptive results had higher clinical pregnancy rates than patients undergoing FET (58.6% vs. 38.6%, P=0.003). rsERT patients with receptive results guided by rsERT with a precise WOI time had higher, although non-significant, clinical pregnancy rates (48.9% vs. 38.6%, P=0.192) than patients who underwent standard-time FET.

Conclusion

Hourly precise rsERT can significantly improve the probability of achieving clinical pregnancy in patients with RIF, especially in those with non-receptive rsERT results.

Kisspeptin expression levels in patients with placenta previa: A randomized trial

BACKGROUND

This study aimed to explore the potential influence of kisspeptin (KISS1) levels on the etiology of placenta previa for early pregnancy diagnosis.

METHODS

The study included 20 pregnant women diagnosed with placenta previa and 20 pregnant woman with normal pregnancies between 2021 and 2022. Plasma KISS1 levels were determined through biochemical analysis, while genetic analysis assessed KISS1 and KISS1 receptor gene expression levels. Immunohistochemical methods were employed to determine placenta KISS1 levels.

RESULTS

The evaluation of KISS1 concentration in serum revealed a significant decrease in the placenta previa group compared to the control group (P < .001). KISS1 gene expression level 0.043-fold decreased in the placenta previa group (P < .001). Furthermore, the KISS1 receptor gene expression level increased 170-fold in the placenta previa group.

CONCLUSIONS

Results from biochemical, immunohistochemical, and genetic analyses consistently indicated significantly reduced KISS1 expression in patients with placenta previa. These findings suggest a potential link between diminished KISS1 levels and the occurrence of placenta previa. KISS1 may play a critical role in the etiology of placenta previa. Detailed studies on angiogenesis, cell migration and tissue modeling should be conducted to understand possible mechanisms.

The effect of Toxoplasma gondii infection on galectin-9 expression in decidual macrophages contributing to dysfunction of decidual NK cells during pregnancy

BACKGROUND

Toxoplasma gondii infection causes adverse pregnancy outcomes by affecting the expression of immunotolerant molecules in decidual immune cells. Galectin-9 (Gal-9) is widely expressed in decidual macrophages (dMφ) and is crucial for maintaining normal pregnancy by interacting with the immunomodulatory protein T-cell immunoglobulin and mucin domain-containing molecule 3 (Tim-3). However, the effects of T. gondii infection on Gal-9 expression in dMφ, and the impact of altered Gal-9 expression levels on the maternal-fetal tolerance function of decidual natural killer (dNK) cells, are still unknown.

METHODS

Pregnancy outcomes of T. gondii-infected C57BL/6 and Lgals9-/- pregnant mice models were recorded. Expression of Gal-9, c-Jun N-terminal kinase (JNK), phosphorylated JNK (p-JNK), and Forkhead box protein O1 (FOXO1) was detected by western blotting, flow cytometry or immunofluorescence. The binding of FOXO1 to the promoter of Lgals9 was determined by chromatin immunoprecipitation-polymerase chain reaction (ChIP-PCR). The expression of extracellular signal-regulated kinase (ERK), phosphorylated ERK (p-ERK), cAMP-response element binding protein (CREB), phosphorylated CREB (p-CREB), T-box expressed in T cells (T-bet), interleukin 10 (IL-10), and interferon gamma (IFN-γ) in dNK cells was assayed by western blotting.

RESULTS

Toxoplasma gondii infection increased the expression of p-JNK and FOXO1 in dMφ, resulting in a reduction in Gal-9 due to the elevated binding of FOXO1 with Lgals9 promoter. Downregulation of Gal-9 enhanced the phosphorylation of ERK, inhibited the expression of p-CREB and IL-10, and promoted the expression of T-bet and IFN-γ in dNK cells. In the mice model, knockout of Lgals9 aggravated adverse pregnancy outcomes caused by T. gondii infection during pregnancy.

CONCLUSIONS

Toxoplasma gondii infection suppressed Gal-9 expression in dMφ by activating the JNK/FOXO1 signaling pathway, and reduction of Gal-9 contributed to dysfunction of dNK via Gal-9/Tim-3 interaction. This study provides new insights for the molecular mechanisms of the adverse pregnancy outcomes caused by T. gondii.

Advances and challenges in organ-on-chip technology: toward mimicking human physiology and disease in vitro

Organs-on-chips have been tissues or three-dimensional (3D) mini-organs that comprise numerous cell types and have been produced on microfluidic chips to imitate the complicated structures and interactions of diverse cell types and organs under controlled circumstances. Several morphological and physiological distinctions exist between traditional 2D cultures, animal models, and the growing popular 3D cultures. On the other hand, animal models might not accurately simulate human toxicity because of physiological variations and interspecies metabolic capability. The on-chip technique allows for observing and understanding the process and alterations occurring in metastases. The present study aimed to briefly overview single and multi-organ-on-chip techniques. The current study addresses each platform's essential benefits and characteristics and highlights recent developments in developing and utilizing technologies for single and multi-organs-on-chips. The study also discusses the drawbacks and constraints associated with these models, which include the requirement for standardized procedures and the difficulties of adding immune cells and other intricate biological elements. Finally, a comprehensive review demonstrated that the organs-on-chips approach has a potential way of investigating organ function and disease. The advancements in single and multi-organ-on-chip structures can potentially increase drug discovery and minimize dependency on animal models, resulting in improved therapies for human diseases.

Oct4 controls basement membrane development during human embryogenesis

Basement membranes (BMs) are sheet-like structures of extracellular matrix (ECM) that provide structural support for many tissues and play a central role in signaling. They are key regulators of cell behavior and tissue functions, and defects in their assembly or composition are involved in numerous human diseases. Due to the differences between human and animal embryogenesis, ethical concerns, legal constraints, the scarcity of human tissue material, and the inaccessibility of the in vivo condition, BM regulation during human embryo development has remained elusive. Using the post-implantation amniotic sac embryoid (PASE), we delineate BM assembly upon post-implantation development and BM disassembly during primitive streak (PS) cell dissemination. Further, we show that the transcription factor Oct4 regulates the expression of BM structural components and receptors and controls BM development by regulating Akt signaling and the small GTPase Rac1. These results represent a relevant step toward a more comprehensive understanding of early human development.

Autophagy genes and signaling pathways in endometrial decidualization and pregnancy complications

Autophagy is a process that occurs in almost all eukaryotic cells and this process is controlled by several molecular processes. Its biological roles include the provision of energy, the maintenance of cell homeostasis, and the promotion of aberrant cell death. The importance of autophagy in pregnancy is gradually becoming recognized. In literature, it has been indicated that autophagy has three different effects on the onset and maintenance of pregnancy: embryo (embryonic development), feto-maternal immune crosstalk, and maternal (decidualization). In humans, proper decidualization is a major predictor of pregnancy accomplishment and it can be influenced by different factors. This review highlights the genes, pathways, regulation, and function of autophagy in endometrial decidualization and other involved factors in this process.

Exploring the effectiveness of endometrial receptivity array and immune profiling in patients with multiple implantation failure：A retrospective cohort study based on propensity score matching

This study aimed to evaluate the effectiveness of the endometrial receptivity array (ERA), endometrial immune profiling, and a combination of both in improving the pregnancy outcomes for multiple implantation failure patients. According to patients' willingness, 1429 women who incurred at least two or more consecutive implantation failures in IVF/ICSI treatment opted for frozen embryo transfer and were divided into four groups: 'No test', 'Immune Profiling', 'ERA' and 'ERA+ Immune Profiling'. Women in three test groups underwent timed endometrial biopsy for ERA, immune profiling, a combination of both. We observed the overall incidence rates of the displaced window of implantation (WOI) and endometrial immune dysregulation were 75.14% and 79.29%, respectively. After 1:1 propensity score matching (PSM), our data revealed that the 'ERA' and 'ERA + Immune Profiling' groups demonstrated significantly higher rates of biochemical, clinical, ongoing pregnancy, and implantation compared to the 'No test' group (p < 0.01). The 'Immune Profiling' group showed a higher implantation rate compared to 'No test' group (p < 0.05). Furthermore, when comparing three test groups, the 'ERA + Immune Profiling' group exhibited notably higher rates of clinical and ongoing pregnancy compared to the 'Immune Profiling' group (p < 0.017). However, there was no association between endometrial immune profiling and ERA phases, and their results did not differ between embryo implantation and non-implantation in these patients. Our findings underline the increased implantation rates by use of ERA and endometrial immune profiling in patients with multiple implantation failure, either individually or corporately. Moreover, a combination of both could improve their pregnancy outcomes significantly.

Efficacy of endometrial receptivity testing for recurrent implantation failure in patients with euploid embryo transfers: study protocol for a randomized controlled trial

BACKGROUND

Embryo implantation remains a critical barrier in assisted reproductive technologies. One of the main causes of unsuccessful embryo implantation is window of implantation (WOI) displacement, particularly in patients with recurrent implantation failure (RIF). Therefore, a reliable diagnostic tool for identifying the optimal WOI is essential. Previous data has suggested that a novel RNA-Seq-based endometrial receptivity testing (ERT) can diagnose WOI, guide personalized embryo transfer (pET), and improve pregnancy outcomes in patients with RIF compared to standard embryo transfer (sET). However, there is still a lack of evidence from randomized controlled trials (RCT) with sufficient power to determine whether pET based on ERT can increase the rate of live births as the primary outcome.

METHODS

This trial is a prospective, single-blind, parallel-group RCT (1:1 ratio of pET versus sET). Infertile women with RIF who intend to undergo frozen-thawed embryo transfer (FET) after preimplantation genetic testing for aneuploidy (PGT-A) with the availability of at least one euploid blastocyst for transfer will be enrolled and assigned into two parallel groups randomly. Participants in the intervention group will undergo ERT and then pET based on the results of ERT, while those in the control group will undergo sET. The primary outcome is live birth rate.

DISCUSSION

The findings of this study will provide evidence for the effect of pET guided by ERT on pregnancy outcomes in patients with RIF.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2100049041. Registered on 20 July 2021.

A novel non-invasive embryo evaluation method (NICS-Timelapse) with enhanced predictive precision and clinical impact

The selection of the finest possible embryo in in-vitro fertilization (IVF) was crucial and revolutionary, particularly when just one embryo is transplanted to lessen the possibility of multiple pregnancies. However, practical usefulness of currently used methodologies may be constrained. Here, we established a novel non-invasive embryo evaluation method that combines non-invasive chromosomal screening (NICS) and Timelapse system along with artificial intelligence algorithms. With an area under the curve (AUC) of 0.94 and an accuracy of 0.88, the NICS-Timelapse model was able to predict blastocyst euploidy. The performance of the model was further evaluated using 75 patients in various clinical settings. The clinical pregnancy and live birth rates of embryos predicted by the NICS-Timelapse model, showing that embryos with higher euploid probabilities were associated with higher clinical pregnancy and live birth rates. These results demonstrated the NICS-Timelapse model's significantly wider application in clinical IVF due to its excellent accuracy and noninvasiveness.

Personalized embryo transfer guided by rsERT improves pregnancy outcomes in patients with repeated implantation failure

Introduction

Embryo implantation requires synchronous communication between the embryo and maternal endometrium. Inadequate maternal endometrial receptivity is one of the principal causes for embryo implantation failure [especially repeated implantation failure (RIF)] when biopsied good-quality euploid embryos are transferred. An RNA-seq-based endometrial receptivity test (rsERT) was previously established to precisely guide successful embryo implantation. In this study, we aimed to evaluate the effect of personalized embryo transfer (pET) via rsERT on the clinical outcomes in patients with RIF.

Methods

A total of 155 patients with RIF were included in the present retrospective study and were divided into two groups: 60 patients who underwent rsERT and pET (Group rsERT) and 95 patients who underwent standard frozen embryo transfer (FET) without rsERT (Group FET). Reproductive outcomes were compared for patients who underwent rsERT-guided pET and standard FET.

Results

Forty percent (24/60) of the patients who underwent rsERT were receptive, and the remaining 60% (36/60) were non-receptive. The positive human chorionic gonadotropin (β-hCG) rate (56.3% vs. 30.5%, P = 0.003) and clinical pregnancy rate (43.8% vs. 24.2%, P = 0.017) were significantly higher in Group rsERT patients than in FET group patients. Additionally, Group rsERT patients also showed a higher implantation rate (32.1% vs. 22.1%, P = 0.104) and live birth rate (35.4% vs. 21.1%, P = 0.064) when compared with FET patients, although without significance. For subpopulation analysis, the positive β-hCG rate, clinical pregnancy rate, implantation rate, and live birth rate of receptive patients were not statistically significant different from those of non-receptive patients.

Conclusions

The rsERT can significantly improve the pregnancy outcomes of RIF patients, indicating the clinical potential of rsERT-guided pET.

Ethical Principles Do Not Support Mandatory Preanesthesia Pregnancy Screening Tests: A Narrative Review

Respect for patient autonomy is a pillar of medical ethics, manifested predominantly through informed consent. Mandatory (routine) nonconsented preoperative urine pregnancy testing does not adequately respect patient autonomy, is potentially coercive, and has the potential to cause harm medically, psychologically, socially, and financially. Inaccuracies in pregnancy testing can result in false-positive and false-negative results, especially in early pregnancy. There is substantial scientific evidence that anesthesia is not harmful to the fetus, raising the question of whether pregnancy testing provides substantial benefit to the patient. Not performing a preanesthesia pregnancy test has not been associated with significant medicolegal consequences. We review the ethical implications of mandatory preanesthesia pregnancy testing in light of these facts.

Aberrant CD8+T cells drive reproductive dysfunction in female mice with elevated IFN-γ levels

Introduction

Interferon-gamma (IFN-γ) is pivotal in orchestrating immune responses during healthy pregnancy. However, its dysregulation, often due to autoimmunity, infections, or chronic inflammatory conditions, is implicated in adverse reproductive outcomes such as pregnancy failure or infertility. Additionally, the underlying immunological mechanisms remain elusive.

Methods

Here, we explore the impact of systemic IFN-γ elevation on cytotoxic T cell responses in female reproduction utilizing a systemic lupus-prone mouse model with impaired IFN-γ degradation.

Results

Our findings reveal that heightened IFN-γ levels triggered the infiltration of CD8+T cells in the pituitary gland and female reproductive tract (FRT), resulting in prolactin deficiency and subsequent infertility. Furthermore, we demonstrate that chronic IFN-γ elevation increases effector memory CD8+T cells in the murine ovary and uterus.

Discussion

These insights broaden our understanding of the role of elevated IFN-γ in female reproductive dysfunction and suggest CD8+T cells as potential immunotherapeutic targets in female reproductive disorders associated with chronic systemic IFN-γ elevation.

Perspectives on folate with special reference to epigenetics and neural tube defects

Folate is a micronutrient essential for DNA synthesis, cell division, fetal growth and development. Folate deficiency leads to genomic instability. Inadequate intake of folate during conception may lead to neural tube defects (NTDs) in the offspring. Folate influences the DNA methylation, histone methylation and homocysteine mediated gene methylation. DNA methylation influences the expression of microRNAs (miRNAs). Folate deficiency may be associated with miRNAs misregulation leading to NTDs. Mitochondrial epigenetics and folate metabolism has proved to be involved in embryogenesis and neural tube development. Folate related genetic variants also cause the occurrence of NTDs. Unmetabolized excessive folate may affect health adversely. Hence estimation of folate levels in the blood plays an important role in high-risk cases.

Bioinformatics analysis of a disease-specific lncRNA-miRNA-mRNA regulatory network in recurrent spontaneous abortion (RSA)

BACKGROUND

This study investigated the molecular mechanisms of long non-coding RNAs (lncRNAs) in RSA using the lncRNA-miRNA-mRNA regulatory network.

METHODS

The present study obtained expression datasets of long non-coding RNAs (lncRNAs), messenger RNAs (mRNAs), and microRNAs (miRNAs) from blood samples of individuals with unexplained recurrent spontaneous abortion (RSA) and healthy controls. Differentially expressed lncRNAs (DELs), mRNAs (DEMs), and miRNAs (DEmiRs) were identified. A regulatory network comprising lncRNA, miRNA, and mRNA was constructed, and Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted to analyze the biological functions of DEM. Also, a protein-protein interaction (PPI) network was made and key genes were identified.

RESULTS

A total of 57 DELs, 212 DEmiRs, and 301 DEMs regarding RSA were identified. Later analysis revealed a lncRNA-miRNA-mRNA network comprising nine lncRNAs, 14 miRNAs, and 65 mRNAs. Then, the ceRNA network genes were subjected to functional enrichment and pathway analysis, which showed their association with various processes, such as cortisol and thyroid hormone synthesis and secretion, human cytomegalovirus infection, and parathyroid hormone synthesis. In addition, ten hub genes (ITGB3, GNAI2, GNAS, SRC, PLEC, CDC42, RHOA, RAC1, CTNND1, and FN1) were identified based on the PPI network results.

CONCLUSION

In summary, the outcomes of our study provided some data regarding the alteration genes involved in RSA pathogenic mechanism via the lncRNA-miRNA-mRNA network and reveal the possibility of identifying new lncRNAs and miRNAs as promising molecular biomarkers.

Minerals and the Menstrual Cycle: Impacts on Ovulation and Endometrial Health

The role of minerals in female fertility, particularly in relation to the menstrual cycle, presents a complex area of study that underscores the interplay between nutrition and reproductive health. This narrative review aims to elucidate the impacts of minerals on key aspects of the reproductive system: hormonal regulation, ovarian function and ovulation, endometrial health, and oxidative stress. Despite the attention given to specific micronutrients in relation to reproductive disorders, there is a noticeable absence of a comprehensive review focusing on the impact of minerals throughout the menstrual cycle on female fertility. This narrative review aims to address this gap by examining the influence of minerals on reproductive health. Each mineral's contribution is explored in detail to provide a clearer picture of its importance in supporting female fertility. This comprehensive analysis not only enhances our knowledge of reproductive health but also offers clinicians valuable insights into potential therapeutic strategies and the recommended intake of minerals to promote female reproductive well-being, considering the menstrual cycle. This review stands as the first to offer such a detailed examination of minerals in the context of the menstrual cycle, aiming to elevate the understanding of their critical role in female fertility and reproductive health.

A GREB1-steroid receptor feedforward mechanism governs differential GREB1 action in endometrial function and endometriosis

Cellular responses to the steroid hormones, estrogen (E2), and progesterone (P4) are governed by their cognate receptor's transcriptional output. However, the feed-forward mechanisms that shape cell-type-specific transcriptional fulcrums for steroid receptors are unidentified. Herein, we found that a common feed-forward mechanism between GREB1 and steroid receptors regulates the differential effect of GREB1 on steroid hormones in a physiological or pathological context. In physiological (receptive) endometrium, GREB1 controls P4-responses in uterine stroma, affecting endometrial receptivity and decidualization, while not affecting E2-mediated epithelial proliferation. Of mechanism, progesterone-induced GREB1 physically interacts with the progesterone receptor, acting as a cofactor in a positive feedback mechanism to regulate P4-responsive genes. Conversely, in endometrial pathology (endometriosis), E2-induced GREB1 modulates E2-dependent gene expression to promote the growth of endometriotic lesions in mice. This differential action of GREB1 exerted by a common feed-forward mechanism with steroid receptors advances our understanding of mechanisms that underlie cell- and tissue-specific steroid hormone actions.

Stromal Pbrm1 mediates chromatin remodeling necessary for embryo implantation in the mouse uterus

Early gestational loss occurs in approximately 20% of all clinically recognized human pregnancies and is an important cause of morbidity. Either embryonic or maternal defects can cause loss, but a functioning and receptive uterine endometrium is crucial for embryo implantation. We report that the switch/sucrose nonfermentable (SWI/SNF) remodeling complex containing polybromo-1 (PBRM1) and Brahma-related gene 1 (BRG1) is essential for implantation of the embryonic blastocyst on the wall of the uterus in mice. Although preimplantation development is unaffected, conditional ablation of Pbrm1 in uterine stromal cells disrupts progesterone pathways and uterine receptivity. Heart and neural crest derivatives expressed 2 (Hand2) encodes a basic helix-loop-helix (bHLH) transcription factor required for embryo implantation. We identify an enhancer of the Hand2 gene in stromal cells that requires PBRM1 for epigenetic histone modifications/coactivator recruitment and looping with the promoter. In Pbrm1cKO mice, perturbation of chromatin assembly at the promoter and enhancer sites compromises Hand2 transcription, adversely affects fibroblast growth factor signaling pathways, prevents normal stromal-epithelial crosstalk, and disrupts embryo implantation. The mutant female mice are infertile and provide insight into potential causes of early pregnancy loss in humans.

tRNAGlu-derived fragments from embryonic extracellular vesicles modulate bovine embryo hatching

Transfer RNA-derived small RNAs (tsRNAs) have been shown to be involved in early embryo development and repression of endogenous retroelements in embryos and stem cells. However, it is unknown whether tsRNAs also regulate embryo hatching. In this study, we mined the sequencing data of a previous experiment in which we demonstrated that the microRNA (miRNA) cargo of preimplantation embryonic extracellular vesicles (EVs) influences embryo development. We thus profiled the tsRNA cargo of EVs secreted by blastocysts and non-blastocysts. The majority of tsRNAs was identified as tRNA halves originating from the 5´ ends of tRNAs. Among the 148 differentially expressed tsRNAs, the 19 nt tRNA fragment (tRF) tDR-14:32-Glu-CTC-1 was found to be significantly up-regulated in EVs derived from non-blastocysts. RT-qPCR assays confirmed its significant up-regulation in non-blastocyst embryos and their conditioned medium compared to the blastocyst group (P < 0.05). Inhibition of tDR-14:32-Glu-CTC-1 by supplementing antagomirs to the conditioned medium improved embryo hatching (P < 0.05). Transcriptomic analysis of embryos treated with tDR-14:32-Glu-CTC-1 antagomirs further showed differential expression of genes that are associated with embryo hatching and implantation. In summary, tDR-14:32-Glu-CTC-1 is up-regulated in non-blastocyst embryos and their secretions, and inhibition of tDR-14:32-Glu-CTC-1 promotes embryo hatching, while influencing embryo implantation-related genes and pathways. These results indicate that embryonic EVs containing specific tRFs may regulate preimplantation embryo development.

Effects of flaxseed oil supplementation on metaphase II oocyte rates in IVF cycles with decreased ovarian reserve: a randomized controlled trial

Background

This study was designed to explore the effects of flaxseed oil on the metaphase II (MII) oocyte rates in women with decreased ovarian reserve (DOR).

Methods

The women with DOR were divided into a study group (n = 108, flaxseed oil treatment) and a control group (n = 110, no treatment). All patients were treated with assisted reproductive technology (ART). Subsequently, the ART stimulation cycle parameters, embryo transfer (ET) results, and clinical reproductive outcomes were recorded. The influencing factors affecting the MII oocyte rate were analyzed using univariate analysis and multivariate analysis.

Results

Flaxseed oil reduced the recombinant human follicle-stimulating hormone (r-hFSH) dosage and stimulation time and increased the peak estradiol (E2) concentration in DOR women during ART treatment. The MII oocyte rate, fertilization rate, cleavage rate, high-quality embryo rate, and blastocyst formation rate were increased after flaxseed oil intervention. The embryo implantation rate of the study group was higher than that of the control group (p = 0.05). Additionally, the female age [odds ratio (OR): 0.609, 95% confidence interval (CI): 0.52-0.72, p < 0.01] was the hindering factor of MII oocyte rate, while anti-Müllerian hormone (AMH; OR: 100, 95% CI: 20.31-495, p < 0.01), peak E2 concentration (OR: 1.00, 95% CI: 1.00-1.00, p = 0.01), and the intake of flaxseed oil (OR: 2.51, 95% CI: 1.06-5.93, p = 0.04) were the promoting factors for MII oocyte rate.

Conclusion

Flaxseed oil improved ovarian response and the quality of oocytes and embryos, thereby increasing the fertilization rate and high-quality embryo rate in DOR patients. The use of flaxseed oil was positively correlated with MII oocyte rate in women with DOR.

Clinical trial number

https://www.chictr.org.cn/, identifier ChiCTR2300073785.