Endometrial responses to embryonic signals in the primate

The Known, the Unknown and the Future of the Pathophysiology of Endometriosis

Endometriosis is one of the most common causes of chronic pelvic pain and infertility, affecting 10% of women of reproductive age. A delay of up to 9 years is estimated between the onset of symptoms and the diagnosis of endometriosis. Endometriosis is currently defined as the presence of endometrial epithelial and stromal cells at ectopic sites; however, advances in research on endometriosis have some authors believing that endometriosis should be re-defined as "a fibrotic condition in which endometrial stroma and epithelium can be identified". There are several theories on the etiology of the disease, but the origin of endometriosis remains unclear. This review addresses the role of microRNAs (miRNAs), which are naturally occurring post-transcriptional regulatory molecules, in endometriotic lesion development, the inflammatory environment within the peritoneal cavity, including the role that cytokines play during the development of the disease, and how animal models have helped in our understanding of the pathology of this enigmatic disease.

Enhancing endometrial receptivity: the roles of human chorionic gonadotropin in autophagy and apoptosis regulation in endometrial stromal cells

Inadequate endometrial receptivity often results in embryo implantation failure and miscarriage. Human chorionic gonadotropin (hCG) is a key signaling molecule secreted during early embryonic development, which regulates embryonic maternal interface signaling and promotes embryo implantation. This study aimed to examine the impact of hCG on endometrial receptivity and its underlying mechanisms. An exploratory study was designed, and endometrial samples were obtained from women diagnosed with simple tubal infertility or male factor infertile (n = 12) and recurrent implantation failure (RIF, n = 10). Using reverse transcription-quantitative PCR and western blotting, luteinizing hormone (LH)/hCG receptor (LHCGR) levels and autophagy were detected in the endometrial tissues. Subsequently, primary endometrial stromal cells (ESCs) were isolated from these control groups and treated with hCG to examine the presence of LHCGR and markers of endometrial receptivity (HOXA10, ITGB3, FOXO1, LIF, and L-selectin ligand) and autophagy-related factors (Beclin1, LC3, and P62). The findings revealed that the expressions of receptivity factors, LHCGR, and LC3 were reduced in the endometrial tissues of women with RIF compared with the control group, whereas the expression of P62 was elevated. The administration of hCG to ESCs specifically activated LHCGR, stimulating an increase in the endometrial production of HOXA10, ITGB3, FOXO1, LIF and L-selectin ligands. Furthermore, when ESCs were exposed to 0.1 IU/mL hCG for 72 h, the autophagy factors Beclin1 and LC3 increased within the cells and P62 decreased. Moreover, the apoptotic factor Bax increased and Bcl-2 declined. However, when small interfering RNA was used to knock down LHCGR, hCG was less capable of controlling endometrial receptivity and autophagy molecules in ESCs. In addition, hCG stimulation enhanced the phosphorylation of ERK1/2 and mTOR proteins. These results suggest that women with RIF exhibit lower levels of LHCGR and compromised autophagy function in their endometrial tissues. Thus, hCG/LHCGR could potentially improve endometrial receptivity by modulating autophagy and apoptosis.

RISING STARS: Approaches to modeling placental function in preeclampsia in vitro and in vivo

Modeling preeclampsia remains difficult due to the nature of the disease and the unique characteristics of the human placenta. Members of the Hominidae superfamily have a villous hemochorial placenta that is different in structure from those of other therian mammals, including the mouse hemochorial placenta, making this common animal model less ideal for studying this disease. Human placental tissues delivered from pregnancies complicated by preeclampsia are excellent for assessing the damage the disease causes but cannot answer how or when the disease begins. Symptoms of preeclampsia manifest halfway through pregnancy or later, making it currently impossible to identify preeclampsia in human tissues obtained from an early stage of pregnancy. Many animal and cell culture models recapitulate various aspects of preeclampsia, though none can on its own completely capture the complexity of human preeclampsia. It is particularly difficult to uncover the cause of the disease using models in which the disease is induced in the lab. However, the many ways by which preeclampsia-like features can be induced in a variety of laboratory animals are consistent with the idea that preeclampsia is a two-stage disease, in which a variety of initial insults may lead to placental ischemia, and ultimately systemic symptoms. The recent development of stem cell-based models, organoids, and various coculture systems have brought in vitro systems with human cells ever closer to recapitulating in vivo events that lead to placental ischemia.

Role of ADAM and ADAMTS Disintegrin and Metalloproteinases in Normal Pregnancy and Preeclampsia

Normal pregnancy (NP) involves intricate processes starting with egg fertilization, proceeding to embryo implantation, placentation and gestation, and culminating in parturition. These pregnancy-related processes require marked uteroplacental and vascular remodeling by proteolytic enzymes and metalloproteinases. A disintegrin and metalloproteinase (ADAM) and ADAM with thrombospondin motifs (ADAMTS) are members of the zinc-dependent family of proteinases with highly conserved protein structure and sequence homology, which include a pro-domain, and a metalloproteinase, disintegrin and cysteine-rich domain. In NP, ADAMs and ADAMTS regulate sperm-egg fusion, embryo implantation, trophoblast invasion, placental angiogenesis and spiral arteries remodeling through their ectodomain proteolysis of cell surface cytokines, cadherins and growth factors as well as their adhesion with integrins and cell-cell junction proteins. Preeclampsia (PE) is a serious complication of pregnancy characterized by new-onset hypertension (HTN) in pregnancy (HTN-Preg) at or after 20 weeks of gestation, with or without proteinuria. Insufficient trophoblast invasion of the uterine wall, inadequate expansive remodeling of the spiral arteries, reduced uteroplacental perfusion pressure, and placental ischemia/hypoxia are major initiating events in the pathogenesis of PE. Placental ischemia/hypoxia increase the release of reactive oxygen species (ROS), which lead to aberrant expression/activity of certain ADAMs and ADAMTS. In PE, abnormal expression/activity of specific ADAMs and ADAMTS that function as proteolytic sheddases could alter proangiogenic and growth factors, and promote the release of antiangiogenic factors and inflammatory cytokines into the placenta and maternal circulation leading to generalized inflammation, endothelial cell injury and HTN-Preg, renal injury and proteinuria, and further decreases in uteroplacental blood flow, exaggeration of placental ischemia, and consequently fetal growth restriction. Identifying the role of ADAMs and ADAMTS in NP and PE has led to a better understanding of the underlying molecular and vascular pathways, and advanced the potential for novel biomarkers for prediction and early detection, and new approaches for the management of PE.

Efficacy of low-dose hCG on FET cycle in patients with recurrent implantation failure

OBJECTIVE

To study patients' new treatment methods and mechanisms of repeated implantation failure.

DESIGN

A retrospective study.

SETTING

In vitro fertilization (IVF) unit in a Three-A hospital.

PATIENTS

Ninety-three patients with repeated implantation failure in IVF and embryo transfer.

INTERVENTIONS

the luteal phase support.

MAIN OUTCOME MEASURES

According to whether human chorionic gonadotropin(HCG) was added, the two groups were divided into an observation group and a control group, and the clinical outcomes of the two groups were compared. Furthermore, 20 patients were selected for whole exome sequencing to investigate the mechanism.

RESULTS

The observation group's clinical pregnancy rate and live birth rate were significantly higher than those in the control group (P=0.004). Functional enrichment analysis showed that these genes were significantly enriched in embryo implantation or endometrial receptivity processes, such as microtubule-based movement, NABA CORE MATRISOME, superoxide anion generation, protein localization to vacuole, extracellular matrix organization, fertilization, microtubule-based transport, cell junction organization, microtubule cytoskeleton organization. Furthermore, variants detected in these pathway genes were missense mutations that affect the protein's biological activity but do not effectuate its inactivation.

CONCLUSIONS

Adding HCG in the luteal phase might improve the clinical pregnancy and live birth rates in RIF patients. The potential pathogenesis of RIF genetic level may be caused by microtubule-based movement, extracellular matrix organization, and the Superoxide Anion generation pathway.

Clinical consequences of defective decidualization

Decidualization is characterized by a series of genetic, metabolic, morphological, biochemical, vascular and immune changes occurring in the endometrial stroma in response to the implanting embryo or even before conception and involves the stromal cells of the endometrium. It is a fundamental reproductive event occurring in mammalian species with hemochorial placentation. A growing body of experimental and clinical evidence strongly suggests that defective or disrupted decidualization contributes to the establishment of an inappropriate maternal-fetal interface. This has relevant clinical consequences, ranging from recurrent implantation failure and recurrent pregnancy loss in early pregnancy to several significant complications of advanced gestation. Moreover, recent evidence indicates that selected diseases of the endometrium, such as chronic endometritis and endometriosis, can have a detrimental impact on the decidualization response in the endometrium and may help explain some aspects of the reduced reproductive outcome associated with these conditions. Further research efforts are needed to fully understand the biomolecular mechanisms ans events underlying an abnormal decidualization response. This will permit the development of new diagnostic and therapeutic strategies aimed to improve the likelihood of achieveing a successful pregnancy.

Human Menopausal Gonadotropin Commenced on Early Follicular Period Increases Live Birth Rates in POSEIDON Group 3 and 4 Poor Responders

Human menopausal gonadotropin (hMG) has LH activity, and it may have beneficial effects in terms of oocyte quality and endometrial receptivity similar to recombinant LH supplementation. The aim of this study was to assess the effects of hMG, and its commencement time on the outcome of assisted reproductive technology (ART) cycles of POSEIDON group 3 and 4 poor responders. Data of 558 POSEIDON group 3 and 4 poor responders who underwent ART treatment following a GnRH antagonist cycle at a university-based infertility clinic between January 2014 and December 2019 were reviewed. hMG was commenced at the early follicular phase or mid-follicular phase in the study groups. The control group did not receive hMG stimulation. Live birth rate (LBR) was the main outcome measure. The mean duration of stimulation was significantly shorter in early follicular hMG group than in mid-follicular hMG group (11.9 ± 3.6 days vs. 12.8 ± 4 days, respectively; P = 0.027). The mean numbers of oocytes retrieved and MII oocytes were comparable between the groups. The LBRs per embryo transfer in early follicular hMG, mid-follicular hMG, and control groups were 21.9%, 11.7%, and 11.6%, respectively (P = 0.035). In conclusion, there is a significant association between the commencement time of hMG and live birth chance in ART cycles of POSEIDON group 3 and 4 poor responders. Early initiation of hMG together with rFSH seems to be beneficial in this specific population.

Comparative secretome profile analysis of cultured immortalized human endometrial stromal cells supplemented with implanted versus nonimplanted blastocyst-conditioned medium: A preliminary analysis

AIM

Human endometrial stromal cells (HESCs) were previously shown to be capable of discriminating embryos with different qualities. Here we aimed to compare the specific response of the HESC secretome to implanted blastocyst-conditioned medium (BCM) versus nonimplanted medium and identify cytokine candidates useful for the assessment of blastocyst implantation.

METHODS

Cleavage embryos were individually cultured in one microdrop of medium for blastocyst formation. The BCM was collected after fresh blastocyst transfer on day 5 and used to supplement HESC culture medium. A high-throughput antibody array covering 440 cytokines was used to detect the secretory proteins of HESCs supplemented with implanted or nonimplanted BCM.

RESULTS

A total of 22 differentially expressed proteins were found out of 440 cytokines in the supernatant of HESCs supplemented with BCM from the implanted group compared to the nonimplanted group, including seven upregulated and 15 downregulated proteins. Gene Ontology enrichment analysis showed that the differentially expressed proteins were mainly involved in cell chemotaxis and motility, and ERK1/2 cascade regulation. Kyoto Encyclopedia of Genes and Genomes analysis suggested that the mitogen-activated protein kinase and phosphatidylinositol 3 kinase/Akt pathways were mainly involved.

CONCLUSION

HESCs specifically responded to BCM from different quality blastocysts, a finding that can be used to develop a novel approach for blastocyst quality assessment.

Detection of IL-6, IL-10, and TNF-α level in human single-blastocyst conditioned medium using ultrasensitive Single Molecule Array platform and its relationship with embryo quality and implantation: a pilot study

PURPOSE

The purpose was to investigate the association between embryonic development or implantation and the content of interleukin-6 and 10 (IL-6, IL-10) and tumor necrosis factor-α (TNF-α) in single-blastocyst conditioned medium (SBCM).

METHODS

Thirty-eight SBCM samples (SBCMs) were collected from blastocysts with different morphological scores. IL-6, IL-10, and TNF-α concentration in 38 SBCMs was detected by Single Molecule Array and compared according to the blastocyst quality: top-quality (TQ) and non-top quality (NTQ), or blastulation time: day 5 (D5) and day 6 (D6). In another experiment, 61 SBCMs were collected from TQ blastocyst transplanted on D5, and IL-6 concentration in SBCM was compared based on whether embryos are implanted or not (implanted and non-implanted).

RESULTS

In the first experiment, IL-6, IL-10, and TNF-α concentration was not significantly different between the TQ-SBCM and NTQ-SBCM. The D6-SBCM had a higher IL-6 concentration compared with the D5-SBCM, while IL-10 and TNF-α concentration was not significantly different between the D5-SBCM and D6-SBCM. The IL-6 concentration in D5-NTQ or D6-TQ SBCM was higher than that in D5-TQ or D6-NTQ SBCM (P < 0.05), respectively. Furthermore, the spearman analysis demonstrated that IL-6 concentration in SBCM was negatively correlated with the blastocyst quality on D5 and positively correlated with the blastocyst quality on D6. In the second experiment, no significant difference in IL-6 concentration was found between SBCM from implanted and non-implanted blastocyst.

CONCLUSION

IL-6 concentration in SBCM was associated with embryo quality depending on the blastulation time, although it might not be associated with the blastocyst implantation.

Transcriptomic changes and potential regulatory mechanism of intrauterine human chorionic gonadotropin co-cultured with peripheral blood mononuclear cells infusion in mice with embryonic implantation dysfunction

Background

This study aimed to explore whether intrauterine infusion of peripheral blood mononuclear cells (PBMCs) could induce favorable transcriptomic changes in the endometrium for embryo implantation and the potential mechanism.

Methods

Twenty-one mice were randomly divided to five groups, including a normal pregnancy (NP) group, an embryo implantation dysfunction (EID) group, an EID with human chorionic gonadotropin (hCG) group, an EID with PBMCs group, and an EID with hCG co-cultured with PBMCs group. The endometrium in the implantation window from mice were collected and determined by RNA sequencing (RNA-Seq), and the expression of significantly different genes with high degree of coincidence was recommended and validated by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

There were totally 1,366 up-regulated and 1,374 down-regulated genes in the EID mice compared with the normal pregnant mice. We selected (fold change ≥2, P<0.05) and verified the candidate genes associated with embryo implantation, immune response and other reproductive processes in previous reports by qRT-PCR. Leukemia inhibitory factor (LIF), solute carrier family 15 member 2 (SLC15A2), retinoic acid receptor responder 1 (RARRES1), vascular cell adhesion molecule 1 (VCAM1) were down-regulated and musculin (MSC), chemokine (C-X-C motif) ligand 14 (CXCL14) were up-regulated significantly in EID group (P<0.05), and the synergistic effects of hCG were seen. In addition, the expression of glucocorticoid receptor (GR)-β in PBMCs of NP mice was higher than that of EID mice, and up-regulated GR-β in EID mice could significantly increase the expression of LIF, SLC15A2, RARRES1 and VCAM1, and decrease the expression of CXCL14 and MSC, which indicated GR-β might be a transcriptional factor of the six genes above.

Conclusions

Intrauterine PBMCs perfusion might improve the performance of impaired endometrial receptivity by regulating LIF, SLC15A2, RARRES1, VCAM1, MSC as well as CXCL14, and hCG could enhance the effect of PBMCs. In addition, GR-β, as a transcriptional factor, could regulate the six genes in PBMCs.

Physiologic Events of Embryo Implantation and Decidualization in Human and Non-Human Primates

Reproduction is a fundamental process for the preservation of the human species. This process requires a sequence of orchestrated events that are necessary for a successful pregnancy. Two of the most critical steps in the establishment of human pregnancy are implantation and decidualization, which are required for maternal interactions with the developing embryo. This review primarily highlights the physiological aspects of these two events and the adverse pregnancy outcomes from defective implantation and decidualization. The focus of this review is to provide a general concept of the mechanisms involved during the window of implantation, description of components involved in the process and possible pathologies that could disrupt the embryo implantation and decidualization and specifically as it applies to women and non-human primates.

The Effect of Intrauterine Administration of Human Chorionic Gonadotropin (hCG) Before Embryo Transfer During Assisted Reproductive Cycles: a Meta-Analysis of Randomized Controlled Trials

The fertility success rates of clinical and laboratory-assisted reproductive techniques (ART) remain low, despite major advances. The aim of this study was to conduct a systematic literature review and assess whether the intrauterine administration of human chorionic gonadotropin (hCG) before embryo transfer (ET) improved the clinical outcomes of sub-fertile women undergoing assisted reproduction. The electronic databases PUBMED, EMBASE and Web of Science were systematically searched for randomized controlled trials (RCTs) published from inception to June 2018. The trial data were independently extracted and analyzed using risk ratios (RRs) and 95% confidence intervals (CIs) according to a random- or fixed-effect model (as appropriate), and a meta-analysis was conducted using Review Manager 5.2 software. The meta-analysis included 3241 patients from 12 RCTs, and the combined results demonstrated that intrauterine hCG injection significantly improved the rates of clinical (RR = 1.33; 95% CI: 1.12 – 1.58) and ongoing pregnancy (RR = 1.87; 95% CI: 1.54 – 2.27), compared with controls. However, intrauterine hCG injection had no significant effect on the implantation rate (RR = 1.30; 95% CI: 0.89 – 1.90), abortion rate (RR = 1.06; 95% CI: 0.78 – 1.44), ectopic pregnancy rate (RR = 0.77; 95% CI: 0.17 – 3.42) or live birth rate (RR = 0.99; 95% CI: 0.60 – 1.63). In a subgroup analysis, the intrauterine injection of > 500 IU hCG led to a significant increase in the implantation rate (RR = 1.64; 95% CI: 1.04 – 2.61) relative to controls. Furthermore, the subgroup of women with cleavage-stage ETs who received an intracavity injection of hCG (IC-hCG) exhibited increases in the implantation, clinical pregnancy and ongoing pregnancy rates, compared to women with cleavage-stage ETs and no IC-hCG. The current evidence indicates that intrauterine hCG administration before ET provides an advantage in terms of the clinical pregnancy and ongoing pregnancy rates.

Obstetric and perinatal outcomes of pregnancies according to initial maternal serum HCG concentrations after vitrified-warmed single blastocyst transfer

RESEARCH QUESTION

Do pregnancy, obstetric and perinatal outcomes differ according to initial maternal serum human chorionic gonadotrophin (HCG) level measured on day 11 after single blastocyst transfer?

DESIGN

Vitrified-warmed single blastocyst transfer cycles (n = 640) were collected between 1 January 2013 and 30 April 2017 with positive HCG values and retrospectively analysed by receiver operating characteristic curves to predict clinical pregnancy, ongoing pregnancy and delivery. Cycles were divided into a low HCG group (n = 155) and high HCG group (n = 485) based on cut-off value of live birth prediction. Cycles in the HCG group were subdivided into a low-high subgroup (n = 162), medium-high subgroup (n = 162) and high-high subgroup (n = 161) based on tertile points. Pregnancy rates and obstetric and perinatal outcomes were compared.

RESULTS

The area under curves for clinical pregnancy, ongoing pregnancy and live birth prediction were 0.95, 0.81 and 0.79, respectively; corresponding cut-off values were 152.2 IU/l, 211.9 IU/l and 211.9 IU/l; HCG less than 211.9 IU/l indicated an extremely low clinical pregnancy rate (34.84%), a high early miscarriage rate (61.11%) and a low live birth rate (12.26%). Rates of gestational diabetes mellitus (GDM) (P = 0.007) and female neonates (P = 0.001) were significantly higher in the LHG group compared with the HHG group; no significant differences were observed in the low versus high HCG group overall.

CONCLUSIONS

Lower initial maternal serum HCG levels indicated poorer clinical outcomes. Within the high HCG group, a lower initial maternal HCG level was found to be associated with GDM occurrence and proportion of female neonates.

The Notch Family Transcription Factor, RBPJκ, Modulates Glucose Transporter and Ovarian Steroid Hormone Receptor Expression During Decidualization

During decidualization, endometrial stromal cells differentiate into a secretory phenotype to modulate the uterine microenvironment and promote embryo implantation. This highly metabolic process relies on ovarian steroid receptors and glucose transporters. Canonical Notch signaling is mediated by the transcription factor Recombination Signal Binding Protein for Immunoglobulin Kappa J Region (RBPJ). Loss of RBPJ in the mouse uterus (Pgr^cre/+Rbpj^flox/flox; Rbpj c-KO) results in subfertility in part due to an abnormal uterine-embryonic axis during implantation and, as described herein, decidualization failure. Induced in vivo decidualization in Rbpj c-KO mice was impaired with the downregulation of decidual markers and decreased progesterone receptor (Pgr) signaling. Consistent with in vivo mouse data, RBPJ knockdown during in vitro Human uterine fibroblast (HuF) cell decidualization results in the reduced expression of decidual marker genes along with PGR. Expression of the glucose transporter, SLC2A1, was decreased in the RBPJ-silenced HuF cells, which corresponded to decreased Slc2a1 in the secondary decidual zone of Rbpj c-KO mouse uteri. Exogenous administration of pyruvate, which bypasses the need for glucose, rescues PRL expression in RBPJ-deficient HuF cells. In summary, Notch signaling through RBPJ controls both ovarian steroid receptor PGR and glucose transporter SLC2A1 expression during decidualization, and this dysregulation likely contributes to embryo implantation failure.

Human chorionic gonadotropin induces decidualization of ectopic human endometrium more effectively than forskolin in an in-vivo endometriosis model

Endometriosis, characterized by the presence of endometrial tissue at ectopic sites, is a leading cause of pelvic pain and subfertility in women. The stromal compartment of the endometrium is considered to play a pivotal role in the establishment and persistence of endometriotic lesions, thus impaired decidualization of these cells may result in enhanced invasion capacity at ectopic sites. Consequently, stimulation of decidualization may alleviate this disease. To analyze the effect of systemically applied compounds on decidualization of ectopic endometrial tissue, endometriosis was induced by suturing human eutopic endometrium to the peritoneum of 22 NOD/SCID mice. Each mouse received four tissue fragments from the same patient. Mice were randomly allocated either to one control and three experimental groups ( n = 4/group) which were treated with progesterone alone or in combination with forskolin or human chorionic gonadotropin for seven days or to one control and one experimental group ( n = 3/group) which was treated with progesterone and human chorionic gonadotropin for 10 days followed by 7 days without treatment. At the end of the experiments, lesions were measured and analyzed for markers of decidualization (FOXO-1, prolactin) and proliferation (Ki-67). Decidualization was induced in the ectopic lesions by systemic treatment in vivo. This induction was significantly stronger after treatment with progesterone in combination with human chorionic gonadotropin than with forskolin or with progesterone alone. Only the combination with human chorionic gonadotropin led to induction of FOXO1 protein expression and a significant physiologic transformation of the ectopic endometrial stromal cells after seven days of treatment. After termination of human chorionic gonadotropin treatment, the decidualization process continued, leading to a significant inhibition of proliferation. Thus, decidualization of human ectopic endometrial tissue can be induced in a humanized endometriosis mouse model in vivo. This model may help to decipher the signal pathways involved in this decidualization process and to develop novel therapeutical approaches to alleviate this painful disease. Impact statement Impaired decidualization of endometrial stromal cells may contribute to the development of endometriosis, and an increased decidualization reaction may prevent or alleviate this prevalent gynecological disease. Human chorionic gonadotropin (hCG) has been shown to promote decidualization in eutopic endometrium. Up to now in vitro studies mainly used cAMP for successful induction of decidualization of isolated endometrial stromal cells. Here, for the first time, decidualization of ectopic endometrial lesions is induced in an experimental endometriosis mouse model, comparing the effectiveness of hCG with that of the direct adenylyl cyclase activator Forskolin. In this 3D-organ structure in vivo, hCG proved to be more effective in the induction of decidualization than forskolin. Particularly in case of progesterone resistance, alternative pathways inducing decidualization could alleviate endometriosis, and the sophisticated hCG action could constitute a therapeutical tool to induce terminal differentiation in ectopic endometrial lesions.

The effect of intrauterine human chorionic gonadotropin flushing on live birth rate after vitrified-warmed embryo transfer in programmed cycles: a randomized clinical trial

PURPOSE

To assess the influence of intrauterine human chorionic gonadotropin (hCG) before embryo transfer on the clinical pregnancy and live birth rates after vitrified-warmed embryo transfer (ET) in programmed cycles.

METHODS

This study was a single-blind randomized clinical trial for eligible patients underwent frozen ET cycles with long-term hormonal GnRH agonist protocol for endometrial preparation. Immediately prior to ET, the women were randomly divided into three groups. In the experimental group, 7-10 min before embryo transfer, 500 IU of hCG with a 40 μL of culture medium was injected into the uterus. In the first control (sham) group, 7-10 min before ET just 40 μL of culture medium intrauterine was infused. In the second control group, no intervention was done. The pregnancy outcomes were compared in the three groups using appropriate statistical tests.

RESULTS

Finally, 180 patients allocated into three groups. There was no significant difference in terms of patients 'characteristics among three groups. No significant difference was found in terms of clinical pregnancy among three groups. The miscarriage rate in control group (0%) was significantly lower than those of in the sham and hCG groups (9.8% and P = 0.01, 6.6% and P = 0.04, respectively). In addition, live birth rate (39.3%) in control group was significantly higher than those of in the sham and hCG groups (16.4% and P = 0.005, 23% and P = 0.051, respectively).

CONCLUSION(S)

It was found that intrauterine injection of 500 IU hCG before vitrified-warmed ET at cleavage stage has no beneficial effect on pregnancy outcome and is not suggested. NCT02355925.

Efficacy and safety of follitropin alfa/lutropin alfa in ART: a randomized controlled trial in poor ovarian responders

STUDY QUESTION

How does the efficacy and safety of a fixed-ratio combination of recombinant human FSH plus recombinant human LH (follitropin alfa plus lutropin alfa; r-hFSH/r-hLH) compare with that of r-hFSH monotherapy for controlled ovarian stimulation (COS) in patients with poor ovarian response (POR)?

SUMMARY ANSWER

The primary and secondary efficacy endpoints were comparable between treatment groups and the safety profile of both treatment regimens was favourable.

WHAT IS KNOWN ALREADY

Although meta-analyses of clinical trials have suggested some beneficial effect on reproductive outcomes with r-hLH supplementation in patients with POR, the definitions of POR were heterogeneous and limit the comparability across studies.

STUDY DESIGN, SIZE, DURATION

Phase III, single-blind, active-comparator, randomized, parallel-group clinical trial. Patients were followed for a single ART cycle. A total of 939 women were randomized (1:1) to receive either r-hFSH/r-hLH or r-hFSH. Randomization, stratified by study site and participant age, was conducted via an interactive voice response system.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women classified as having POR, based on criteria incorporating the ESHRE Bologna criteria, were down-regulated with a long GnRH agonist protocol and following successful down-regulation were randomized (1:1) to COS with r-hFSH/r-hLH or r-hFSH alone. The primary efficacy endpoint was the number of oocytes retrieved following COS. Safety endpoints included the incidence of adverse events, including ovarian hyperstimulation syndrome (OHSS). Post hoc analyses investigated safety outcomes and correlations between live birth and baseline characteristics (age and number of oocytes retrieved in previous ART treatment cycles or serum anti-Müllerian hormone (AMH)). The significance of the treatment effect was tested by generalized linear models (Poisson regression for counts and logistic regression for binary endpoints) adjusting for age and country.

MAIN RESULTS AND THE ROLE OF CHANCE

Of 949 subjects achieving down-regulation, 939 were randomized to r-hFSH/r-hLH (n = 477) or r-hFSH (n = 462) and received treatment.

Efficacy assessment: In the intention-to-treat (ITT) population, the mean (SD) number of oocytes retrieved (primary endpoint) was 3.3 (2.71) in the r-hFSH/r-hLH group compared with 3.6 (2.82) in the r-hFSH group (between-group difference not statistically significant). The observed difference between treatment groups (r-hFSH/r-hLH and r-hFSH, respectively) for efficacy outcomes decreased over the course of pregnancy (biochemical pregnancy rate: 17.3% versus 23.9%; clinical pregnancy rate: 14.1% versus 16.8%; ongoing pregnancy rate: 11.0% versus 12.4%; and live birth rate: 10.6% versus 11.7%). An interaction (identified post hoc) between baseline characteristics related to POR and treatment effect was noted for live birth, with r-hFSH/r-hLH associated with a higher live birth rate for patients with moderate or severe POR, whereas r-hFSH was associated with a higher live birth rate for those with mild POR. A post hoc logistic regression analysis indicated that the incidence of total pregnancy outcome failure was lower in the r-hFSH/r-hLH group (6.7%) compared with the r-hFSH group (12.4%) with an odds ratio of 0.52 (95% CI 0.33, 0.82; P = 0.005).

Safety assessment: The overall proportion of patients with treatment-emergent adverse events (TEAEs) occurring during or after r-hFSH/r-hLH or r-hFSH use (stimulation or post-stimulation phase) was 19.9% and 26.8%, respectively. There was no consistent pattern of TEAEs associated with either treatment.

LIMITATIONS, REASONS FOR CAUTION

Despite using inclusion criteria for POR incorporating the ESHRE Bologna criteria, further investigation is needed to determine the impact of the heterogeneity of POR in the Bologna patient population. The observed correlation between baseline clinical characteristics related to POR and live birth rate, as well as the observed differences between groups regarding total pregnancy outcome failure were from post hoc analyses, and the study was not powered for these endpoints. In addition, the attrition rate for pregnancy outcomes in this trial may not reflect general medical practice. Furthermore, as the patient population was predominantly White these results might not be applicable to other ethnicities.

WIDER IMPLICATIONS OF THE FINDINGS

In the population of women with POR investigated in this study, although the number of oocytes retrieved was similar following stimulation with either a fixed-ratio combination of r-hFSH/r-hLH or r-hFSH monotherapy, post hoc analyses showed that there was a lower rate of total pregnancy outcome failure in patients receiving r-hFSH/r-hLH, in addition to a higher live birth rate in patients with moderate and severe POR. These findings are clinically relevant and require additional investigation. The benefit:risk balance of treatment with either r-hFSH/r-hLH or r-hFSH remains positive.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by Merck KGaA, Darmstadt, Germany. P.H. has received honoraria for lectures and unrestricted research grants from Ferring, Merck KGaA and MSD. D.R. is a former employee of EMD Serono, a business of Merck KGaA, Darmstadt, Germany. J.S., J.H. and W.C. are employees of EMD Serono Research and Development Institute, a business of Merck KGaA, Darmstadt, Germany. T.D.’H. and S.L. are employees of Merck KGaA, Darmstadt, Germany.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier: NCT02047227; EudraCT Number: 2013-003817-16.

TRIAL REGISTRATION DATE

ClinicalTrials.gov: 24 January 2014; EudraCT: 19 December 2013.

DATE OF FIRST PATIENT'S ENROLMENT

30 January 2014.

Effect of intrauterine injection of human chorionic gonadotropin before embryo transfer on pregnancy rate: A prospective randomized study

BACKGROUND

Human chorionic gonadotropin (hCG) as the most important factor to controlled implantation is one of the early embryonic signals in primates that is secreted by the embryo before its implantation. This study was designed to assess the effects of intrauterine injection of hCG before the embryo transfer in an in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycle on pregnancy rate in infertile patients.

MATERIALS AND METHODS

This randomized study was done on 100 infertile patients in two groups: intervention group received injection of 700 IU of intrauterine hCG 10 min before embryo transfer and control group did not receive hCG. The pregnancy rate was tested 2 weeks after embryo transfer, and if the pregnancy test was positive, a transvaginal ultrasound was performed 3 weeks later to search for signs of pregnancy, such as the presence of a gestational sac, embryo, and fetal heart rate, and confirmed as successful pregnancy.

RESULTS

Pregnancy test was positive in 13 (28.6%) of 46 patients in hCG group and in control group was positive in 6 (12.5%) of 48 patients. The pregnancy rate between hCG group and control group was not significantly different (P = 0.54). The pregnancy rate in hCG group with IVF fertilization was 20.8% and in their controls was 7.4% (P = 0.51). The pregnancy rate in hCG group with ICSI fertilization was 36.4% and in their controls was 19% (P = 0.16).

CONCLUSION

The intrauterine injection of 700 IU of hCG before embryo transfer improved pregnancy rate compared to control group but was not significantly different.

Notch signalling in placental development and gestational diseases

Activation of Notch signalling upon cell-cell contact of neighbouring cells controls a plethora of cellular processes such as stem cell maintenance, cell lineage determination, cell proliferation, and survival. Accumulating evidence suggests that the pathway also critically regulates these events during placental development and differentiation. Herein, we summarize our present knowledge about Notch signalling in murine and human placentation and discuss its potential role in the pathophysiology of gestational disorders. Studies in mice suggest that Notch controls trophectoderm formation, decidualization, placental branching morphogenesis and endovascular trophoblast invasion. In humans, the particular signalling cascade promotes formation of the extravillous trophoblast lineage and regulates trophoblast proliferation, survival and differentiation. Expression patterns as well as functional analyses indicate distinct roles of Notch receptors in different trophoblast subtypes. Altered effects of Notch signalling have been detected in choriocarcinoma cells, consistent with its role in cancer development and progression. Moreover, deregulation of Notch signalling components were observed in pregnancy disorders such as preeclampsia and fetal growth restriction. In summary, Notch plays fundamental roles in different developmental processes of the placenta. Abnormal signalling through this pathway could contribute to the pathogenesis of gestational diseases with aberrant placentation and trophoblast function.

GRIM-19, a gene associated with retinoid-interferon-induced mortality, affects endometrial receptivity and embryo implantation

GRIM-19 is associated with apoptosis, abnormal proliferation, immune tolerance and malignant transformation, and it also plays an important role in early embryonic development. Although the homologous deletion of GRIM-19 causes embryonic lethality in mice, the precise role of GRIM-19 in embryo implantation has not been elucidated. Here we show that GRIM-19 plays an important role in endometrial receptivity and embryo implantation. Day 1 to Day 6 pregnant mouse uteri were collected. Immunohistochemistry studies revealed the presence of GRIM-19 on the luminal epithelium and glandular epithelium throughout the implantation period in pregnant mice. The protein and mRNA levels of GRIM-19 were markedly decreased on Day 4 of pregnancy in pregnant mice, but there was no change in GRIM-19 levels in a group of pseudopregnant mice. Overexpression of GRIM-19 decreased the adhesion rate of RL95–2–BeWo co-cultured spheroids and increased apoptosis. Furthermore, STAT3 and IL-11 mRNA and protein levels were reduced by overexpressing GRIM-19, but protein and mRNA levels of TNF-α were increased. These findings indicate the involvement of GRIM-19 in the embryo implantation process by regulating adhesion, apoptosis and immune tolerance.

Lentiviral vector-mediated down-regulation of Notch1 in endometrial stem cells results in proliferation and migration in endometriosis

The recent characterization of stem/progenitor cells in the endometrium has shed new light for pathogenesis of endometriosis. The present study was undertaken to investigate the role of Notch1, known as a cell fate regulator, in the mechanism of endometriosis. Influence of Notch1 on endometrial stem cells proliferation and migration was evaluated by knocking down Notch1 expression using shRNA. Furthermore, human endometrial stromal and epithelial stem cells with or without LV-Notch1-shRNA were injected into the peritoneal cavity of nude mice, to assess the in vivo effects of a specific antagonist of Notch1 on the progression of endometriosis. The results showed that LV-Notch1-shRNA led to a significant decline of clonogenicity and migration in human endometrial stem cells in vitro, as well as the size of endometriotic lesions in murine models. These data provide evidence that specific inhibition of Notch1 alters endometriotic tissue growth and progression, and may represent a promising potential therapeutic avenue.

The effect of intrauterine human chorionic gonadotropin injection before embryo transfer on the implantation and pregnancy rate in infertile patients: A randomized clinical trial

BACKGROUND

Implantation is one of the essential steps for the success of assisted reproductive techniques (ART). Their success depends on three main factors: embryo quality, endometrial receptivity (ER), and synchrony between embryo and endometrium. There are various factors that regulate the complex process of implantation. In this regard, one may refer to human chorionic gonadotropin (hCG) as the most important factor.

OBJECTIVE

This study aims to investigate the effect of intrauterine hCG injection before embryo transfer (ET) on pregnancy outcome in infertile couples.

MATERIALS AND METHODS

A total of 159 patients undergone In vitro Fertilization/ Intracytoplasmic Sperm Injection (IVF/ICSI) with an antagonist protocol were evaluated. Patients were divided into three groups (n=53). Group 1 received 500 IU of hCG, group 2 received 1000 IU of hCG intrauterine injection before ET, and the control group underwent ET without hCG preceding intrauterine injection.

RESULTS

There was no significant difference among the groups. The implantation rates were 18.86%, 13.52%, and 14.37%, chemical pregnancy rates were 34%, 32.1%, and 35.3%, and clinical pregnancy rates were 34%, 32.1%, and 31.4% respectively.

CONCLUSION

The pregnancy outcome in IVF/ICSI /ET cycles cannot be improved through hCG intrauterine injections before ET.

Intrauterine human chorionic gonadotropin infusion in oocyte donors promotes endometrial synchrony and induction of early decidual markers for stromal survival: a randomized clinical trial

STUDY QUESTION

Does a single intrauterine infusion of human chorionic gonadotropin (hCG) at the time corresponding to a Day 3 embryo transfer in oocyte donors induce favorable molecular changes in the endometrium for embryo implantation?

SUMMARY ANSWER

Intrauterine hCG was associated with endometrial synchronization between endometrial glands and stroma following ovarian stimulation and the induction of early decidual markers associated with stromal cell survival.

WHAT IS KNOWN ALREADY

The clinical potential for increasing IVF success rates using an intrauterine hCG infusion prior to embryo transfer remains unclear based on previously reported positive and non-significant findings. However, infusion of CG in the non-human primate increases the expression of pro-survival early decidual markers important for endometrial receptivity, including α-smooth muscle actin (α-SMA) and NOTCH1.

STUDY DESIGN, SIZE, DURATION

Oocyte donors (n=15) were randomly assigned to receive an intrauterine infusion of 500 IU hCG (n=7) or embryo culture media vehicle (n=8) 3 days following oocyte retrieval during their donor stimulation cycle. Endometrial biopsies were performed 2 days later, followed by either RNA isolation or tissue fixation in formalin and paraffin embedding.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Reverse transcription of total RNA from endometrial biopsies generated cDNA, which was used for analysis in the endometrial receptivity array (ERA; n = 5/group) or quantitative RT-PCR to determine relative expression of ESR1, PGR, C3 and NOTCH1. Tissue sections were stained with hematoxylin and eosin followed by blinded staging analysis for dating of endometrial glands and stroma. Immunostaining for ESR1, PGR, α-SMA, C3 and NOTCH1 was performed to determine their tissue localization.

MAIN RESULTS AND THE ROLE OF CHANCE

Intrauterine hCG infusion was associated with endometrial synchrony and reprograming of stromal development following ovarian stimulation. ESR1 and PGR were significantly elevated in the endometrium of hCG-treated patients, consistent with earlier staging. The ERA did not predict an overall positive impact of intrauterine hCG on endometrial receptivity. However, ACTA2, encoding α-SMA was significantly increased in response to intrauterine hCG. Similar to the hCG-treated non-human primate, sub-epithelial and peri-vascular α-SMA expression was induced in women following hCG infusion. Other known targets of hCG in the baboon were also found to be increased, including C3 and NOTCH1, which have known roles in endometrial receptivity.

LIMITATIONS, REASONS FOR CAUTION

This study differs from our previous work in the hCG-treated non-human primate along with clinical studies in infertile patients. Specifically, we performed a single intrauterine infusion in oocyte donors instead of either continuous hCG via an osmotic mini-pump in the baboon or infusion followed by blastocyst-derived hCG in infertile women undergoing embryo transfer. Therefore, the full impact of intrauterine hCG in promoting endometrial receptivity may not have been evident.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings suggest a potential clinical benefit for intrauterine hCG prior to embryo transfer on Day 3 in counteracting endometrial dyssynchrony from ovarian stimulation and promoting expression of markers important for stromal survival. Finally, there were no obvious negative effects of intrauterine hCG treatment.

STUDY FUNDING/COMPETING INTERESTS

Funding for this work was provided by NICHD R01 HD042280 (A.T.F.) and NICHD F30 HD082951 (M.R.S.). C.S. and P.D.-G are co-inventors of the patented ERA, which is owned by IGENOMIX SL and was used in this study, and C.S. is a shareholder in IGENOMIX SL. M.R.-A. is employed by IGENOMIX SL. No other authors have any conflicts of interest to report.

TRIAL REGISTRATION NUMBER

This study was registered with ClinicalTrials.gov (NCT01786252).

TRIAL REGISTRATION DATE

5 February 2013.

DATE OF FIRST PATIENT'S ENROLLMENT

10 May 2013.

Appreciation for Analysis of how Levonorgestrel Works and Reservations with the use of Meloxicam as Emergency Contraception

This paper is a response to Dr. Kathleen Raviele's recent article on her critical analysis of the use of levonorgestrel given to women postsexual assault and her suggestion that the use of Meloxicam may be an ethical alternative.

The role of invasive trophoblast in implantation and placentation of primates

We here review the evolution of invasive placentation in primates towards the deep penetration of the endometrium and its arteries in hominoids. The strepsirrhine primates (lemurs and lorises) have non-invasive, epitheliochorial placentation, although this is thought to be derived from a more invasive type. In haplorhine primates, there is differentiation of trophoblast at the blastocyst stage into syncytial and cellular trophoblast. Implantation involves syncytiotrophoblast that first removes the uterine epithelium then consolidates at the basal lamina before continuing into the stroma. In later stages of pregnancy, especially in Old World monkeys and apes, cytotrophoblast plays a greater role in the invasive process. Columns of trophoblast cells advance to the base of the implantation site where they spread out to form a cytotrophoblastic shell. In addition, cytotrophoblasts advance into the lumen of the spiral arteries. They are responsible for remodelling these vessels to form wide, low-resistance conduits. In human and great apes, there is additional invasion of the endometrium and its vessels by trophoblasts originating from the base of the anchoring villi. Deep trophoblast invasion that extends remodelling of the spiral arteries to segments in the inner myometrium evolved in the common ancestor of gorilla, chimp and human.

The efficacy of intrauterine injection of human chorionic gonadotropin before embryo transfer in assisted reproductive cycles: Meta-analysis

OBJECTIVES

A systematic review and meta-analysis to evaluate the effect of human chorionic gonadotropin (hCG) intrauterine injection before embryo transfer on the outcome of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

METHODS

Searches of PubMed®, EMBASE®, EBSCO, Web of Science®, SCOPUS® and Cochrane Central Register of Controlled Trials were conducted to retrieve relevant randomized controlled trials (RCTs). Data were extracted and analysed.

RESULTS

The meta-analysis included five RCTs (hCG group n = 680; control group n = 707). Intrauterine hCG injection significantly increased rates of biochemical, clinical and ongoing pregnancy compared with controls. There were no between-group differences in implantation or miscarriage rates.

CONCLUSION

Women undergoing IVF/ICSI may benefit from intrauterine hCG injection before embryo transfer.

Implantation and Establishment of Pregnancy in Human and Nonhuman Primates

Implantation and the establishment of pregnancy are critical for the propagation of the species, but yet remain the limiting steps in human and primate reproduction. Successful implantation requires a competent blastocyst and a receptive endometrium during a specific window of time during the menstrual cycle to initiate the bilateral communication required for the establishment of a successful pregnancy. This chapter provides an overview of these processes and discusses the molecular mechanisms associated with implantation of the blastocyst and decidualization of the uterus in primates.

In vitro fertilization outcome following embryo transfer with or without preinstillation of human chorionic gonadotropin into the uterine cavity: a randomized controlled trial

BACKGROUND

Intrauterine injection of human chorionic gonadotropin (hCG) at embryo transfer (ET) has been shown to improve the outcome of assisted reproductive techniques. The aim of this study was to confirm previous findings.

METHODS

In this randomized controlled trial, 483 infertile women who were candidates for in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) for the first time were randomly assigned to receive an intrauterine injection of 500 IU hCG or placebo (tissue culture media) before ET. The main outcome measures were implantation and clinical pregnancy rates.

RESULTS

Both the hCG-treated group (n = 240) and control group (n = 243) were similar at baseline in terms of demographic and obstetrical characteristics. There were significant differences between the two groups regarding the implantation rate (23.6 vs. 12.2%, p < 0.001), pregnancy rate (54.6 vs. 35.8%, p < 0.001), clinical pregnancy rate (50 vs. 32.1%, p < 0.001), ongoing pregnancy rate (15.3 vs. 9.2%, p < 0.001) and live delivery rate (14.3 vs. 8.4%, p < 0.001). The rate of fertilization and abortion rates were not statistically different.

CONCLUSION

Intrauterine injection of hCG before ET improves implantation and pregnancy rates and may be considered an adjuvant in IVF/ICSI.

Endometrial infusion of human chorionic gonadotropin at the time of blastocyst embryo transfer does not impact clinical outcomes: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

To determine whether endometrial hCG infusion at the time of human blastocyst transfer impacts implantation rates.

DESIGN

Randomized double-blinded placebo-controlled trial.

SETTING

Academic.

PATIENT(S)

Infertile couples with the female partner less than 43 years old (n = 300) undergoing fresh or frozen ET of one or two blastocysts.

INTERVENTION(S)

Patients undergoing ET were randomized into either a treatment or a control group. The treatment group received an infusion of 500 IU of hCG diluted in ET media. The control group received a sham infusion of ET media. Infusions were done using a separate catheter less than 3 minutes before actual ET.

MAIN OUTCOME MEASURE(S)

Sustained implantation rate: ongoing viable gestation (primary outcome) and ongoing pregnancy rate (secondary outcome).

RESULT(S)

A total of 473 blastocysts were transferred into 300 patients. There were no differences between the two groups in sustained implantation rate (48.1% in the hCG group, 44.2% in the control group) or ongoing pregnancy rate (58.8% in the hCG group, 52.0% in the control group).

CONCLUSION(S)

Endometrial infusion of hCG at the time of blastocyst ET does not improve sustained implantation rates.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01643993.

Why primate models matter

Research involving nonhuman primates (NHPs) has played a vital role in many of the medical and scientific advances of the past century. NHPs are used because of their similarity to humans in physiology, neuroanatomy, reproduction, development, cognition, and social complexity-yet it is these very similarities that make the use of NHPs in biomedical research a considered decision. As primate researchers, we feel an obligation and responsibility to present the facts concerning why primates are used in various areas of biomedical research. Recent decisions in the United States, including the phasing out of chimpanzees in research by the National Institutes of Health and the pending closure of the New England Primate Research Center, illustrate to us the critical importance of conveying why continued research with primates is needed. Here, we review key areas in biomedicine where primate models have been, and continue to be, essential for advancing fundamental knowledge in biomedical and biological research.

The evolution of embryo implantation

Embryo implantation varies widely in placental mammals. We review this variation in mammals with a special focus on two features: the depth of implantation and embryonic diapause. We discuss the two major types of implantation depth, superficial and interstitial, and map this character on a well-resolved molecular phylogenetic tree of placental mammals. We infer that relatively deep interstitial implantation has independently evolved at least eight times within placental mammals. Moreover, the superficial type of implantation represents the ancestral state for placental mammals. In addition, we review the genes involved in various phases of implantation, and suggest a future direction in investigating the molecular evolution of implantation-related genes.

Profiles of cytokines secreted by isolated human endometrial cells under the influence of chorionic gonadotropin during the window of embryo implantation

BACKGROUND

Several studies have indicated that human pre-implantation embryo-derived chorionic gonadotropin (hCG) may influence the implantation process by its action on human endometrial epithelial and stromal cells. Despite reports indicating that hCG acts on these cells to affect the production of several cytokines and growth factors (e.g., MIF, IGF-I, VEGF, LIF, IL-11, GMCSF, CXL10 and FGF2), our understanding of the integral influence of hCG on paracrine interactions between endometrial stromal and epithelial cells during implantation is very limited.

METHODS

In the present study, we examined the profile of 48 cytokines in the conditioned media of primary cell cultures of human implantation stage endometrium. Endometrial epithelial cells (group 1; n = 20), stromal cells (group 2; n = 20), and epithelial plus stromal cells (group 3; n = 20) obtained from mid-secretory stage endometrial samples (n = 60) were grown on collagen and exposed to different doses (0, 1, 10 and 100 IU/ml) of rhCG for 24 h in vitro. Immunochemical and qRT-PCR methods were used to determine cytokine profiles. Enrichment and process networks analyses were implemented using a list of cytokines showing differential secretion in response to hCG.

RESULTS

Under basal conditions, endometrial epithelial and stromal cells exhibited cell type-specific profiles of secreted cytokines. Administration of hCG (100 IU) resulted in significantly (P < 0.05) different cytokine secretion profiles indicative of macropinocytic transport (HGF, MCSF) in epithelial cells, signal transduction (CCL4, FGF2, IL-1b, IL-6, IL-17, VEGF) in stromal cells, and epithelial-mesenchymal transition (FGF2, HGF, IL-1b, TNF) in mixed cells. Overall, the administration of hCG affected cytokines involved in the immune response, chemotaxis, inflammatory changes, proliferation, cell adhesion and apoptosis.

CONCLUSIONS

CG can influence the function of the endometrium during blastocyst implantation via its differential action on endometrial epithelial and stromal cells. CG may also affect complex paracrine processes in the different endometrial cell types.

In-vitro model systems for the study of human embryo-endometrium interactions

Implantation requires highly orchestrated interactions between the developing embryo and maternal endometrium. The association between abnormal implantation and reproductive failure is evident, both in normal pregnancy and in assisted reproduction patients. Failure of implantation is the pregnancy rate-limiting step in assisted reproduction, but, as yet, empirical interventions have largely failed to address this problem. Better understanding of the mechanisms underlying human embryo-endometrium signalling is a prerequisite for the further improvement of assisted reproduction outcomes and the development of effective interventions to prevent early pregnancy loss. Studying human embryo implantation is challenging since in-vivo experiments are impractical and unethical, and studies in animal models do not always translate well to humans. However, in recent years in-vitro models have been shown to provide a promising way forward. This review discusses the principal models used to study early human embryo development and initial stages of implantation in vitro. While each model has limitations, exploiting these models will improve understanding of the molecular mechanisms and embryo-endometrium cross-talk at the early implantation site. They provide valuable tools to study early embryo development and pathophysiology of reproductive disorders and have revealed novel disease mechanisms such as the role of epigenetic modifications in recurrent miscarriage.

Complement C3 and decay-accelerating factor expression levels are modulated by human chorionic gonadotropin in endometrial compartments during the implantation window

The control of complement activation in the embryo-maternal environment has been demonstrated to be critical for embryo survival. Complement proteins are expressed in the human endometrium; however, the modulation of this expression by embryo signals has not been explored. To assess the expression of complement proteins in response to human chorionic gonadotropin (hCG), we designed an experimental study using in vivo and in vitro models. Twelve fertile women were treated with hCG or left untreated during the mid-luteal phase, and an endometrial biopsy was performed 24 hours later. The localizations of C3, membrane cofactor protein (MCP; CD46), decay-accelerating factor (DAF; CD55), and protectin (CD59) were assessed by immunohistochemistry, and the messenger RNA (mRNA) levels of these proteins were quantified by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) in cells harvested from endometrial compartments using laser capture microdissection. Endometrial explants were cultured with or without hCG for 24 hours, and the C3 and DAF protein levels were measured by Western blotting. Elevated C3 mRNA levels in stromal cells and elevated DAF levels in epithelial luminal cells were detected after hCG treatment. In the endometrial explant model, the progesterone receptor antagonist RU486 inhibited the increases in the levels of C3 and DAF in response to hCG. The findings of this study indicate that hCG plays a role in embryo-endometrium communication and affects the expression of complement proteins in endometrial compartments during the implantation window.

Investigation of gene expression profiles before and after embryonic genome activation and assessment of functional pathways at the human metaphase II oocyte and blastocyst stage

OBJECTIVE

To compare the oocyte versus the blastocyst transcriptome and provide data on molecular pathways before and after embryonic genome activation.

DESIGN

Prospective laboratory research study.

SETTING

An IVF clinic and a specialist preimplantation genetics laboratory.

PATIENT(S)

Couples undergoing or having completed IVF treatment donating surplus oocytes or cryopreserved blastocysts after patient consent.

INTERVENTION(S)

Sets of pooled metaphase II (MII) oocytes or blastocysts were processed for RNA extraction, RNA amplification, and analysis with the use of the Human Genome Survey Microarrays v2.0 (Applied Biosystems).

MAIN OUTCOME MEASURE(S)

Association of cell type and gene expression profile.

RESULT(S)

Totals of 1,909 and 3,122 genes were uniquely expressed in human MII oocytes and human blastocysts respectively, and 4,910 genes were differentially expressed between the two sample types. Expression levels of 560 housekeeping genes, genes involved in the microRNA processing pathway, as well as hormones and hormone receptors were also investigated.

CONCLUSION(S)

The lists of genes identified may be of use for understanding the processes involved in early embryo development and blastocyst implantation, and for identifying any dysregulation leading to infertility.

Interaction of the conceptus and endometrium to establish pregnancy in mammals: role of interleukin 1β

Implantation and the establishment of pregnancy in mammals involves an intricate interplay of hormones, cytokines, growth factors, proteins, lipids, ions and the extracellular matrix between the uterine epithelium, stroma, immune cells and the conceptus trophectoderm. The divergent nature of implantation in the mouse, human and pig provides not only an interesting contrast in the establishment of pregnancy and early embryonic development but also intriguing similarities with regard to early endometrial-conceptus signaling. An interesting pro-inflammatory cytokine expressed in a number of mammalian species during the period of implantation is interleukin-1β (IL1B). The presence of IL1B might be involved with immunotolerance at the maternal-placental interface and has been proposed as one of the mediators in placental viviparity. The production of IL1B and other proinflammatory cytokines might play a role in establishing pregnancy through modulation of the nuclear factor kappa-B (NFKB) system in a number of species. A model for the regulation of cellular progesterone receptor expression and NFKB activation for endometrial receptivity and conceptus attachment is continuing to evolve and is discussed in the present review.

Human placentation from nidation to 5 weeks of gestation. Part II: Tools to model the crucial first days

Human pregnancy is unusual with respect to monthly spontaneous decidualisation as well as the degree of placental invasion and interaction with the decidualised endometrial stroma. This review covers in vivo animal models and in vitro cell culture models that have been used to study the earliest stages of human implantation and placentation from nidation to 5 weeks of gestation. The field has expanded rapidly in recent years due to the generation of human embryonic stem cell lines and the ability of some scientists to culture human blastocysts. These models have enabled researchers to begin to elucidate the interactions involved in human blastocyst apposition, adhesion and implantation. However, we still understand very little about the differentiation processes involved in the formation of the placenta. Continued improvements to current models, including the potential isolation of a human trophoblast stem cell, will significantly enhance our ability to define the molecular and structural events occurring during human implantation and early placental development.

Culture systems: embryo density

Embryo density is defined as the embryo-to-volume ratio achieved during in vitro culture; in other words, it is the number of embryos in a defined volume of culture medium. The same density can be achieved by manipulating either the number of embryos in a given volume of medium, or manipulating the volume of the medium for a given number of embryos: for example, a microdrop with five embryos in a 50 μl volume under oil has the same embryo-to-volume ratio (1:10 μl) as a microdrop with one embryo in a 10 μl volume under oil (1:10 μl). Increased embryo density can improve mammalian embryo development in vitro; however, the mechanism(s) responsible for this effect may be different with respect to which method is used to increase embryo density.Standard, flat sterile plastic petri dishes are the most common, traditional platform for embryo culture. Microdrops under a mineral oil overlay can be prepared to control embryo density, but it is critical that dish preparation is consistent, where appropriate techniques are applied to prevent microdrop dehydration during preparation, and results of any data collection are reliable, and repeatable. There are newer dishes available from several manufacturers that are specifically designed for embryo culture; most are readily available for use with human embryos. The concept behind these newer dishes relies on fabrication of conical and smaller volume wells into the dish design, so that embryos rest at the lowest point in the wells, and where putative embryotrophic factors may concentrate.Embryo density is not usually considered by the embryologist as a technique in and of itself; rather, the decision to culture embryos in groups or individually is protocol-driven, and is based more on convenience or the need to collect data on individual embryos. Embryo density can be controlled, and as such, it can be utilized as a simple, yet effective tool to improve in vitro development of human embryos.

The evolution of menstruation: a new model for genetic assimilation: explaining molecular origins of maternal responses to fetal invasiveness

Why do humans menstruate while most mammals do not? Here, we present our answer to this long-debated question, arguing that (i) menstruation occurs as a mechanistic consequence of hormone-induced differentiation of the endometrium (referred to as spontaneous decidualization, or SD); (ii) SD evolved because of maternal-fetal conflict; and (iii) SD evolved by genetic assimilation of the decidualization reaction, which is induced by the fetus in non-menstruating species. The idea that menstruation occurs as a consequence of SD has been proposed in the past, but here we present a novel hypothesis on how SD evolved. We argue that decidualization became genetically stabilized in menstruating lineages, allowing females to prepare for pregnancy without any signal from the fetus. We present three models for the evolution of SD by genetic assimilation, based on recent advances in our understanding of the mechanisms of endometrial differentiation and implantation. Testing these models will ultimately shed light on the evolutionary significance of menstruation, as well as on the etiology of human reproductive disorders like endometriosis and recurrent pregnancy loss.

Research resource: interactome of human embryo implantation: identification of gene expression pathways, regulation, and integrated regulatory networks

A prerequisite for successful embryo implantation is adequate preparation of receptive endometrium and the establishment and maintenance of a viable embryo. The success of implantation further relies upon a two-way dialogue between the embryo and uterus. However, molecular bases of these preimplantation and implantation processes in humans are not well known. We performed genome expression analyses of human embryos (n = 128) and human endometria (n = 8). We integrated these data with protein-protein interactions in order to identify molecular networks within the endometrium and the embryo, and potential embryo-endometrium interactions at the time of implantation. For that, we applied a novel network profiling algorithm HyperModules, which combines topological module identification and functional enrichment analysis. We found a major wave of transcriptional down-regulation in preimplantation embryos. In receptive-stage endometrium, several genes and signaling pathways were identified, including JAK-STAT signaling and inflammatory pathways. The main curated embryo-endometrium interaction network highlighted the importance of cell adhesion molecules in the implantation process. We also identified cytokine-cytokine receptor interactions involved in implantation, where osteopontin (SPP1), leukemia inhibitory factor (LIF) and leptin (LEP) pathways were intertwining. Further, we identified a number of novel players in human embryo-endometrium interactions, such as apolipoprotein D (APOD), endothelin 1 (END1), fibroblast growth factor 7 (FGF7), gastrin (GAST), kringle containing trnasmembrane protein 1 (KREMEN1), neuropilin 1 (NRP1), serpin peptidase inhibitor clade A member 3 (SERPINA3), versican (VCAN), and others. Our findings provide a fundamental resource for better understanding of the genetic network that leads to successful embryo implantation. We demonstrate the first systems biology approach into the complex molecular network of the implantation process in humans.