Differential effects of human chorionic gonadotropin and decidualization on insulin-like growth factors-I and -II in human endometrial stromal cells

Meta-analysis of intrauterine hCG perfusion efficacy in recurrent implantation failure as defined by ESHRE guidelines

PURPOSE

This study evaluates the efficacy of intrauterine hCG perfusion for RIF, as defined by ESHRE 2023 guidelines, highlighting hCG as a cost-effective alternative to other immunotherapies, especially suitable for less developed regions. It aims to clarify treatment guidance amidst previous inconsistencies.

METHODS

This meta-analysis, registered with PROSPERO (CRD42024443241) and adhering to PRISMA guidelines, assessed the efficacy and safety of intrauterine hCG perfusion in enhancing implantation and pregnancy outcomes in RIF. Comprehensive literature searches were conducted through December 2023 in major databases including PubMed, Web of Science, Embase, the Cochrane Library, and key Chinese databases, without language restrictions. Inclusion and exclusion criteria were strictly aligned with the 2023 ESHRE recommendations, with exclusions for studies lacking robust control, clear outcomes, or adequate data integrity. The risk of bias was evaluated using the Newcastle-Ottawa Scale, ROBINS-I, and RoB2 tools. Data analysis was performed in R using the 'meta' package, employing both fixed and random effect models to account for study variability. Subgroup analyses by dosage, volume, hCG concentration, timing of administration, and type of embryo transfer were conducted to deepen insights, enhancing the reliability and depth of the meta-analysis in elucidating the role of hCG perfusion in RIF treatments.

RESULTS

Data from 13 studies, comprising six retrospective and six prospective studies from single centers, along with one multi-center RCT, totaling 2,157 participants, were synthesized to evaluate the effectiveness of intrauterine hCG perfusion in enhancing implantation and pregnancy outcomes in patients with RIF. Significant improvements were observed in clinical pregnancy and embryo implantation rates across various dosages, timing of administration, and embryo developmental stages, without impacting miscarriage rates. Notably, the most significant efficacy within subgroups occurred with a 500 IU dosage and perfusion parameters of ≤ 500µL volume and ≥ 2 IU/µL concentration. Additionally, a limited number of studies showed no significant increases in ectopic pregnancy or multiple pregnancy rates, and a modest improvement in live birth rates, although the small number of these studies precludes definitive conclusions.

CONCLUSIONS

The analysis suggests that intrauterine hCG perfusion probably enhances embryo implantation, clinical pregnancy, and live birth rates slightly in RIF patients. Benefits are indicated with a dosage of 500 IU and a maximum volume of 500µL at concentrations of at least 2 IU/µL. However, substantial heterogeneity from varying study types and the limited number of studies necessitate cautious interpretation. These findings underscore the need for more rigorously designed RCTs to definitively assess the efficacy and safety.

Intramuscular injection of human chorionic gonadotropin as luteal phase support in artificial cycle frozen-thawed embryo transfer does not improve clinical outcomes: a parallel, open-label randomized trial

Background

Human chorionic gonadotropin (hCG) as one of the first signals secreted by the embryo to the mother may have a direct effect on the endometrium at implantation. The current study was aim to compare the clinical outcomes after frozen-thawed embryo transfer (FET) treated with artificial cycles (AC) between women who were administered intramuscular injection of human chorionic gonadotropin (hCG) as luteal phase support and the routine group.

Methods

A randomized controlled trial of 245 women was conducted at the Assisted Reproduction Center, Northwest Women's and Children's Hospital, Xi'an, China from January 2019 to January 2020. Women <40 years of age undergoing their first FET treated with AC were included. Patients were randomly allocated into either: (1) the hCG treatment group, who received intramuscular injection of hCG since the third day of progesterone administration, at a dose of 2000 IU once every two days, for a total of four times, (2) the control group, receiving routine protocol without placebo on these four days. Clinical outcomes of the two groups were analyzed.

Results

The primary outcome ongoing pregnancy rate in the hCG treatment group versus the control group was 73/124 (58.87%) versus 75/121 (61.98%), respectively (odds ratio [OR], 95% confidence interval [CI]:0.88, 0.53-1.47, P = 0.619). Secondary clinical outcomes including biochemical pregnancy, clinical pregnancy, early pregnancy loss, multiple pregnancy, live birth and preterm birth were also comparable between the two groups through the univariate analysis and multivariable regression analysis (P > 0.05).

Conclusion

In women undergoing AC-FET, there was no significant difference in the clinical outcomes between the hCG treatment group and the control group. Clinicians should be cautious about adding IM-hCG as luteal phase support to improve the clinical outcome after AC-FET.

Clinical trial registration

http://www.chictr.org.cn/showprojen.aspx?proj=32511, identifier ChiCTR1800020342.

Intrauterine instillation of human chorionic gonadotropin at the time of blastocyst transfer: Systematic review and meta-analysis

Intrauterine instillation (IU) of Human Chorionic Gonadotropin (hCG) before embryo transfer (ET) has been proposed to enhance implantation success rates. This is the first meta-analysis to evaluate the effect at the blastocyst-stage. A systematic literature search was performed using Medline, Embase, Cochrane Library and Google. Randomized clinical trials (RCTs) were included. The primary outcome combined live birth rate (LBR) and ongoing pregnancy rate (OPR). The secondary outcomes were clinical pregnancy rate (CPR), implantation rate (IR) and miscarriage rate (MR). 93 citations were identified, of which there were seven eligible RCTs. 2499 participants were included in the meta-analysis; 1331 were assigned to an experimental group and 1168 were assigned to the control group. The overall effect of IU hCG instillation on LBR and OPR was not significant: risk ratio (RR) 1.00 (95% CI, 0.90-1.12). Analysis of secondary outcomes found the effect of IU hCG instillation was not significant. Analysis of the data suggests that the studies conducted have too much heterogeneity to identify whether a specific cohort may have a significant benefit. The findings of this meta-analysis demonstrate that there is insufficient evidence at present to support the use of IU hCG instillation prior to blastocyst-stage ET.

Low Molecular Weight Heparins (LMWH) and Implications along Pregnancy: a Focus on the Placenta

Low molecular weight heparins (LMWH) have been largely studied for their use during pregnancy. The biology and the pharmacology of these molecules are well known and may be summarized in three main mechanisms of action: anti-coagulant, anti-inflammatory, and immunomodulant. The clinical implications of these drugs during pregnancy are mainly related to their action on the placenta, because of the presence of specific molecular and cellular targets, particularly at the trophoblast-endometrial interface. As well as for the prevention and treatment of thromboembolism, LMWH have been largely investigated for the improvement of embryo implantation and for the prevention of placenta-related complications such as preeclampsia, fetal growth restriction, and intrauterine fetal death. However, data on this topic are still unclear. The present review discusses the biological features, the mechanisms of action, and the possible contribution of LMWH to the success of placentation along pregnancy, pointing out the need for future basic science and clinical researches in this important field with the final aim to improve clinical practice in high-risk pregnancies.

Approaches to Improve Endometrial Receptivity in Case of Repeated Implantation Failures

Repeated implantation failures are a constant challenge in reproductive medicine with a significant impact both on health providers and on infertile couples. Several approaches have been proposed so far as effective; however, accumulative data have clarified that most of the treatment options do not have the evidence base for a generalized application to be suggested by the relevant societies. Implantation failures are attributed to either poor quality embryos or to defected endometrial receptivity. The current review aims to summarize in a systematic way all the new trends in managing RIF via interference with endometrial receptivity. The authors focus mainly, but not exclusively, on endometrial injury prior to embryo transfer and endometrial priming with autologous cells or biological agents. To this direction, a systematic search of the Pubmed database has been conducted taking into account the emerged evidence of the last two decades. All the suggested interventions are herein presented and analyzed in terms of reproductive outcomes. It is evident that properly powered and designed randomized trials are needed to support a new standard approach in RIF treatment that will safely be incorporated in national and international guidelines.

Low body mass index is associated with ectopic pregnancy following assisted reproductive techniques: a retrospective study

OBJECTIVE

To investigate the association between body mass index (BMI) and ectopic pregnancy (EP) following embryo transfer (ET).

DESIGN

Retrospective cohort study.

SETTING

University-affiliated hospital.

POPULATION

A total of 16 378 pregnancies derived from either fresh ET or frozen-thawed ET between January 2008 and December 2017.

METHODS

We used the generalised estimating equation (GEE) to analyse the association between BMI categories and EP, as one woman may contribute to more than one pregnancy. Generalised additive models were also used to demonstrate the non-linear association. Models were adjusted for age, parity, gravidity, previous history of ectopic pregnancy, duration of infertility, polycystic ovary syndrome, endometriosis, diagnosis of tubal problems, ovarian reserve markers, ovarian stimulation parameters, insemination protocol, endometrial thickness and embryo transfer policies.

MAIN OUTCOME MEASURES

Ectopic pregnancy.

RESULTS

According to the WHO criteria, the number of cycles with low (<18.5 kg/m² ), normal (18.5-24.9 kg/m² ) and high (≥25 kg/m² ) BMI were 2155, 13 447 and 776, respectively. In comparison with the normal BMI group, the rate of EP was significantly increased in the low BMI group (2.92% versus 2.02%, relative risk 1.45, 95% CI 1.11-1.90), but not in the high BMI group (2.84%, relative risk 1.41, 95% CI 0.92-2.20). Adjusted for confounding factors, the odds ratio for EP comparing low BMI versus normal BMI was 1.61 (95% CI 1.19-2.16) and that comparing high BMI versus normal BMI was 1.12 (95% CI 0.72-1.76).

CONCLUSIONS

Low BMI is associated with an increased risk of EP.

TWEETABLE ABSTRACT

The ectopic pregnancy rate after embryo transfer for lean women is higher than that for women of normal weight.

The impact of hyaluronan-enriched culture medium and intrauterine infusion of human chorionic gonadotropin on clinical outcomes in blastocyst transfer cycles

Over the last few decades, advances in ovarian hormonal stimulation, embryology laboratory technologies and embryo genetic testing, have significantly enhanced clinical outcomes in human assisted reproduction technologies (ART). However, embryo implantation remains a major bottleneck in achieving better pregnancy and live birth rates. Thus, there is growing interest in establishing new approaches to enhance implantation efficiency after embryo transfer. With advanced molecular techniques, many promising biomarkers associated with embryonic and endometrial changes occurring prior to and during embryo implantation have been identified. However, despite the progress in applying novel procedures into IVF practice, clinical evaluation of those biomarkers has so far reached modest predictive value for enhancing blastocyst developmental potential and endometrial receptivity. Therefore, other simpler strategies have also been introduced to increase the rates of successful clinical pregnancies and live births. One of these approaches is to investigate the impact of using embryo transfer medium containing high concentrations of an adherence compound, such as hyaluronic acid (HA), on IVF outcomes. Additionally, intrauterine infusion of a small volume of human chorionic gonadotropin (hCG) at the time of embryo transfer (ET) has also been proposed as a technique that might be advantageous for increasing the clinical outcomes, considering the fact that hCG plays a critical role in synchronizing endometrial and fetal development. However, the current findings from both interventions remain controversial, demonstrating a mixture of positive and indifferent results of these treatments in ART cycles. Further research will be crucial for a better understanding of the molecular mechanism of cross-talk between the blastocyst and the maternal endometrium during the optimal implantation period when using either hyaluronan-enriched medium or hCG infusion before embryo transfers. Therefore, this review aims to present existing literature related to both treatments, emphasizing their effects on blastocyst implantation.Abbreviations: ART: assisted reproduction technologies; HA: hyaluronic acid; hCG: human chorionic gonadotrophin; IVF: in vitro Fertilization; ET: embryo transfer; pH: hydrogen ions; CO2: Carbone dioxide; O2: Oxygen; PGT: pre-implantation genetic testing; FET: frozen embryo transfer; PCOS: Polycystic ovarian syndrome; DNA: deoxyribonucleic acid; miRNA: micro-ribonucleic acid; EVs: extracellular vesicles; ERA: endometrial receptivity array; CD44 and RHAMM: primary hyaluronan surface receptors; RCT: randomized clinical trials; LBR: life birth rate; CPR: clinical pregnancy rate; IR: implantation rate.

Regulation of Embryonic Signal on Talin1 in Mouse Endometrium

Embryonic signals can affect the spatiotemporal-specific expression of the uterus to establish a successful pregnancy. Our previous study has found that talin1 underwent dynamic changes in the mouse endometrium during peri-implantation period. However, whether talin1 is affected by the embryo signals is not clear. In order to investigate the effect of embryonic signals, especially human chorionic gonadotropin (HCG) on talin1, we have designed mouse models of pseudopregnancy, delayed implantation and activation, and HCG treatment. Using these models, the expression of talin1 in the mouse endometrium was determined by immunohistochemistry and Western blotting. In the pseudopregnancy model, an increased expression of talin1 was found from day 3 to day 5, whereas the talin1 protein was decreased on day 5 in the normal pregnant mice. In the delayed implantation model, a strong cytoplasmic staining of talin1 was found, especially in stromal cells. However, after activation of the implantation, the expression of talin1 decreased (P < .05). Furthermore, a significantly lower expression of talin1 was found at the implantation site when compared to the interimplantation sites (P < .05). In the HCG treatment model, an intrauterine perfusion of 10u HCG significantly reduced the expression of talin1 in both stromal and epithelial cells in pseudopregnant mice (P < .05), although further increase in the HCG concentration did not have additional effect on expression of talin1. Taken together, our data suggest that the presence of embryos can affect expression of talin1 in the mouse endometrium, and a certain concentration of HCG can regulate its expression.

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 Role of HCG in Implantation: A Mini-Review of Molecular and Clinical Evidence

Embryo implantation is a complex process involving continuous molecular cross-talk between the embryo and the decidua. One of the key molecules during this process is human chorionic gonadotropin (HCG). HCG effectively modulates several metabolic pathways within the decidua contributing to endometrial receptivity. Herein, a brief overview of the molecular mechanisms regulated by HCG is presented. Furthermore, we summarize the existing evidence regarding the clinical impact on reproductive outcomes after endometrial priming with HCG prior to embryo transfer. Although promising, further evidence is needed to clarify the protocol that would lead to beneficial outcomes.

Does intrauterine injection of low-molecular-weight heparin improve the clinical pregnancy rate in intracytoplasmic sperm injection?

Objective

Heparin can modulate proteins, and influence processes involved in implantation and trophoblastic development. This study aimed to assess the improvement of clinical pregnancy and implantation rates after local intrauterine injection of low-molecular-weight heparin (LMWH) in patients undergoing intracytoplasmic sperm injection (ICSI).

Methods

A randomised case/control design was followed in women scheduled for ICSI. The study arm was injected with intrauterine LMWH during mock embryo transfer immediately following the ovum pickup procedure, while the control arm was given an intrauterine injection with a similar volume of tissue culture media. Side effects, the clinical pregnancy rate, and the implantation rate were recorded.

Results

The pregnancy rate was acceptable (33.9%) in the LMWH arm with no significant reported side effects, confirming the safety of the intervention. No statistically significant differences were found in the clinical pregnancy and implantation rates between both groups (p=0.182 and p=0.096, respectively). The odds ratio of being pregnant after intrauterine injection with LMWH compared to the control group was 0.572 (95% confidence interval [CI], 0.27−1.22), while the risk ratio was 0.717 (95% CI, 0.46−1.13; p=0.146). No statistical significance was found between the two groups in other factors affecting implantation, such as day of transfer (p=0.726), number of embryos transferred (p=0.362), or embryo quality.

Conclusion

Intrauterine injection of LMWH is a safe intervention, but the dose used in this study failed to improve the outcome of ICSI. Based on its safety, further research involving modification of the dosage and/or the timing of administration could result in improved ICSI success rates.

Therapeutic Potential of Human Chorionic Gonadotropin Against Painful Bladder Syndrome/Interstitial Cystitis

Painful bladder syndrome/interstitial cystitis is a debilitating chronic bladder disease that primarily affects women. The disease is due to a damage of urothelial cell lining. As a result, potassium particles and other toxic substances in urine can leak into bladder mucosa, causing the symptoms of lower abdominal/pelvic discomfort, pain, increased urination frequency, urgency, nocturia, and so on, all of which can substantially reduce the quality of daily life. There are multiple symptom reliving therapies. Among them, only pentosan polysulfate sodium, sold under the brand name of Elmiron, has been approved for oral use by US Food and Drug Administration. It provides the relief after several months of use. Based on the scientific leads presented in this article, we propose that human chorionic gonadotropin has a therapeutic potential that is worth investigating for the treatment of this disease.

The presence of heparins during decidualization modulates the response of human endometrial stromal cells to IL-1β in vitro

PURPOSE

The aim of this paper is to study the impact of heparin on the response of human endometrial stromal cells (ESCs) to interleukin (IL)-1β during decidualization in vitro.

METHODS

ESCs were isolated from hysterectomy specimens of premenopausal women undergoing hysterectomy for benign reasons; decidualized in vitro and incubated in parallel with unfractionated heparin or tinzaparin; and stimulated with IL-1β at days 0, 3, 6, and 9 during decidualization. IL-6, IL-11, and leukemia inhibitory factor (LIF) were analyzed using ELISAs and real-time RT-PCR. Cell viability was determined by a fluorometric assay.

RESULTS

IL-1β dose-dependently stimulated IL-6, IL-11, and LIF in distinct patterns in ESCs during decidualization. Unfractionated heparin as well as tinzaparin attenuated the IL-1β-mediated induction of IL-6, IL-11, and LIF on protein and messenger RNA (mRNA) levels. The relative effects of heparin and tinzaparin were getting more pronounced during the time course of decidualization.

CONCLUSIONS

Unfractionated heparin and the low molecular weight heparin tinzaparin have modulating effects on IL-1β-induced endometrial cytokines of the IL-6 family during decidualization. These effects of heparins beyond their classical anti-coagulatory properties might have implications on the regulation of endometrial receptivity and early implantation.

Interferon-γ differentially modulates the impact of tumor necrosis factor-α on human endometrial stromal cells

The pro-inflammatory T helper (Th)-1 cytokines, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), are immunological factors relevant at the feto-maternal interface and involved in the pathophysiology of implantation disorders. The synergistic action of the two cytokines has been described with regard to apoptotic cell death and inflammatory responses in different cell types, but little is known regarding the human endometrium. Therefore, we examined the interaction of TNF-α and IFN-γ in human endometrial stromal cells (ESCs). ESCs were isolated from specimens obtained during hysterectomy and decidualized in vitro. Cells were incubated with TNF-α, IFN-γ or signaling-inhibitor. Insulin-like growth factor binding protein (IGFBP)-1, prolactin (PRL), leukemia inhibitory factor (LIF), interleukin (IL)-6, IL-8, regulated on activation normal T-cell expressed and secreted protein (RANTES) and monocyte chemotactic protein (MCP)-1 were measured using ELISA and real-time RT-PCR. Nuclear factor of transcription (NF)-κB and its inhibitor (IκBα) were analyzed by in-cell western assay and transcription factor assay. TNF-α inhibited and IFN-γ did not affect the decidualization of ESCs. In contrast, IFN-gamma differentially modulated the stimulating effect of TNF-alpha on cytokines by enhancing IL-6, RANTES and MCP-1 and attenuating LIF mRNA expression. These effects were time- and dose-dependent. IFN-γ had no impact on the initial activation of NF-κB signaling. Histone-deacetylase activity was involved in the modulating effect of IFN-γ on RANTES secretion. These observations showed a distinct pattern of interaction of the Th-1 cytokines, TNF-α and IFN-γ in the human endometrium, which could play an important role in the pathophysiology of implantation disorders.

Heparin modulates chemokines in human endometrial stromal cells by interaction with tumor necrosis factor α and thrombin

OBJECTIVE

To study the impact of heparins on chemokines in decidualized human endometrial stromal cells (ESCs) in vitro.

DESIGN

In vitro experiment.

SETTING

Research laboratory.

PATIENT(S)

Premenopausal women undergoing hysterectomy for benign reasons.

INTERVENTION(S)

ESCs were isolated from hysterectomy specimens, decidualized in vitro and incubated with unfractionated heparin and low-molecular-weight heparins (LMWHs) as well as tumor necrosis factor (TNF) α or thrombin with or without heparins.

MAIN OUTCOME MEASURE(S)

Chemokines CXCL1, CXCL5, CXCL8, CCL2, and CCL5 were measured with the use of ELISA, and CXCL5, CXCL8, CCL2, and CCL5 were detected with the use of real-time reverse-transcription polymerase chain reaction. Cell viability was determined with the use of a fluorometric assay.

RESULT(S)

TNF-α and thrombin stimulated distinct patterns of chemokines in ESCs. Unfractionated heparin and LMWHs attenuated the TNF-α-mediated induction of CXCL8 and enhanced CXCL5, CCL2, and CCL5. The stimulating effect of thrombin on CXCL8 could be inhibited by heparin, whereas heparin had no impact on thrombin-induced CXCL1 and CCL2. Nuclear factor of transcription κB signaling mediated the effects of TNF-α. The effects of thrombin were mediated via extracellular signal-regulated protein kinases 1/2.

CONCLUSION(S)

Heparins have modulating effects on TNF-α- and thrombin-induced endometrial chemokines, which might have implications in the regulation of endometrial receptivity and early implantation.

Human chorionic gonadotropin (hCG) modulation of TIMP1 secretion by human endometrial stromal cells facilitates extravillous trophoblast invasion in vitro

STUDY QUESTION

Are secreted extracellular matrix (ECM) remodelling elements, relevant to embryo implantation and placentation, modified by hCG in endometrial stromal cells (ESCs)?

SUMMARY ANSWER

hCG decreases tissue inhibitor of metalloproteinase 1 (TIMP-1) secretion in ESCs, thereby facilitating extravillous trophoblast invasion in vitro.

WHAT IS KNOWN ALREADY

Successful embryo implantation and placentation depend on the appropriate invasion of the trophoblast into the maternal endometrial stroma. hCG is one of the earliest embryo-derived secreted signals in the endometrium which abundantly expresses hCG receptors. However, there is little data concerning the effects of hCG on endometrial ECM remodelling with respect to embryo implantation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study was conducted in an academic research laboratory within a tertiary-care hospital. Samples were collected from 36 women undergoing benign gynaecological surgery during the mid-secretory phase. ESCs were isolated and stimulated with hCG (10 UI/ml) or vehicle. Conditioned media (CM) were analysed to determine changes in the secreted profile of nine matrix metalloproteinases (MMPs) and three tissue-specific inhibitors of MMPs (TIMPs) using an ELISA array. Data were confirmed by gelatine zymography, western blot and ELISA. The HTR8/SVneo cell line served as a model for trophoblast cells. The invasive potential of trophoblast cells was assessed using Transwell invasion assays under CM or co-culture conditions with ECS and the role of regulated molecules was examined by using immunoprecipitation in CM prior to the assessment of invasive potential.

MAIN RESULTS AND THE ROLE OF CHANCE

MMP-2 levels increased 30%, whereas TIMP-1 levels decreased 20% in CM from ESCs stimulated with hCG (P < 0.05). Gelatine zymography confirmed an increase in MMP-2 activity (P < 0.05). ELISA and western blotting also confirmed the reduction in TIMP-1 upon hCG treatment (P < 0.05). Invasion assays revealed a ∼50% increase in invading HTR8/SVneo cells in chambers with hCG-stimulated ESCs compared with the control (P < 0.05). Immunodepletion of TIMP-1 from control ESC-CM partially resembled the effect of CM from hCG-stimulated ESCs in the trophoblast invasion assays.

LIMITATIONS, REASONS FOR CAUTION

The assays were performed in vitro and ESCs were not decidualized, therefore they reflected the very early stages of embryo implantation or the advanced stages when decidualization fails.

WIDER IMPLICATIONS OF THE FINDINGS

Our data suggest that hCG induces endometrial stromal extracellular remodelling by modulating secreted MMP-2 and TIMP-1. This regulation may be physiologically relevant because it increases the invasive potential of trophoblast-derived cells. At present, few data exist concerning the implications of hCG and endometrial ECM remodelling in embryo implantation. Hence, our results should be confirmed by further in vivo studies.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by FONDECYT 11100443, PBCT-PSD51 (IDIMI) and FONDAP 15010006. None of the authors have any conflicts of interest to declare.

Expression patterns of Notch receptors and their ligands Jagged and Delta in human placenta

The establishment of an appropriate fetomaternal vessel system is a prerequisite for prevention of pregnancy associated pathologies. Notch receptors and ligands are manifoldly involved in vascular development and angiogenesis. To further characterize the process of human placental vasculo- and angiogenesis we investigated the expression pattern of Notch receptors and their ligands during pregnancy. Real time RT-PCR, immunohistochemistry and flow cytometry analysis were performed in early (6-12) weeks of gestation (w.o.g.) and late placenta (37-41 w.o.g.). To specify the exact cellular localization immunofluorescent labelling of epithelial and endothelial cells (EC), respectively, with cytokeratin-7 and vonWillebrand factor (vWF) was done. One placenta from a patient with Alagille syndrome (AGS) was examined with real time RT-PCR and immunohistochemistry. The receptors Notch2, -3, -4 and their ligands Jagged1, -2 and Delta1, -4 were detected at both the mRNA and protein level in early and late placenta. Notch1 was only detected at protein level. The expression was found mainly in the stromal compartment: placental EC expressed Notch1, Delta4, Jagged1 and Delta1. A strong Jagged1 expression was found in the endothelium of arteries and veins supporting a role in differentiation of capillaries. Hofbauer cells (HC) primarily displayed the receptors Notch2, -3 and -4. Placental stromal cells (SC) were positive for Jagged2. The syncytiotrophoblast (ST) and cytotrophoblast (CT) cells revealed a weak but detectable co-localization with cytokeratin-7 and Notch1, -3 and Delta1. These results were verified by flow cytometry of freshly isolated placental cells of placental tissue. Interestingly Jagged1 expression was absent in endothelial cells from an AGS placenta. The Notch receptors and their ligands are expressed in human placental ST, CT, EC, SC and HC. The distribution pattern of Notch receptors and their ligands suggests their involvement in the process of placental vasculo- and angiogenesis via cell-cell communication between trophoblast, -stroma and endothelial cells.

Heparin inhibits interferon-γ signaling in human endometrial stromal cells by interference with the cellular binding of interferon-γ

OBJECTIVE

To examine the impact of heparins on interferon-γ (IFN-γ) signaling in human endometrial stromal cells (ESCs) in vitro.

DESIGN

In vitro experiment.

SETTING

Research laboratory at a medical university center.

PATIENT(S)

Premenopausal women undergoing hysterectomy for benign reasons.

INTERVENTION(S)

The ESCs were isolated from hysterectomy specimens, decidualized in vitro using P and 17β-E(2), and incubated with recombinant IFN-γ, unfractionated heparin, and low molecular weight heparins (LMWHs).

MAIN OUTCOME MEASURE(S)

Interferon response factor 1 (IRF-1) and N-myc interactor (Nmi) messenger RNA (mRNA) were measured using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Phosphorylation of signal transducer and activator of transcription 1 (STAT-1) was detected by an in-cell Western assay, expression of the IFN-γ receptor by flow cytometry. Cell-bound IFN-γ was determined in lysates by an ELISA.

RESULT(S)

Heparin and LMWHs inhibit the IFN-γ-mediated induction of IRF-1, but not Nmi in undifferentiated and decidualized ESCs. The phosphorylation of signal transducer and activator of transcription 1 STAT-1 upon IFN-γ stimulation is inhibited as well. Heparin has no effect on the IFN-γ receptor in ESCs, but inhibits the binding of IFN-γ to the cells.

CONCLUSION(S)

Unfractionated heparin, as well as LMWHs, are able to inhibit IFN-γ signaling in human ESCs and therefore might be clinically interesting agents to modulate the actions of this proinflammatory cytokine at the implantation site.

Hsa-miR-222 is involved in differentiation of endometrial stromal cells in vitro

Decidualization is a critical step during embryo implantation and characterized by the differentiation of endometrial stromal cells (ESCs) into decidual cells. Because miRNAs are important determinants of cellular fate specification, in this study, the miRNA expression in ESCs during in vitro decidualization was profiled by using a microarray. Significance analysis of microarrays revealed that 49 miRNA genes were differently (>2-fold) expressed between the noninduced ESCs and induced ESCs with a false discovery rate of 0. The expression variance of hsa-miR-222, 221, 143, 101, 30d, 30c, 181b, 27b, 29b, 507, and 23a was validated by using quantitative PCR (P < 0.05). Based on microRNA (miRNA) and mRNA expression variance and predicted target genes of miRNAs, a bioinformatic model of miRNAs controlling ESCs differentiation was formulated. Finally, we proved that down-regulation of has-miR-222 could decrease the number of cells in S phase during ESCs differentiation (P < 0.05). Antisense oligonucleotides of has-miR-222 could increase reporter gene expression by targeting the 3' untranslated regions of CDKN1C/p57kip2 mRNAs as well as increase CDKN1C/p57kip2 protein levels (P < 0.05). In conclusion, our results suggest that a subset of miRNAs play a key role in gene reprogramming during ESCs decidualization and that hsa-miR-222 participates in ESC differentiation by regulating ESCs terminally withdrawing from the cell cycle.

Inverse regulation of the interferon-gamma receptor and its signaling in human endometrial stromal cells during decidualization

OBJECTIVE

To investigate whether human endometrial stromal cells (ESCs) express the interferon-gamma-receptor (IFN-gamma R) and whether the process of decidualization or human chorionic gonadotropin (hCG) regulate the IFN-gamma R and its signaling pathway.

DESIGN

In vitro experiment.

SETTING

Research laboratory at a medical university center.

PATIENT(S)

Premenopausal women undergoing hysterectomy for benign reasons.

INTERVENTION(S)

Isolation and incubation of ESCs from hysterectomy specimens with 17beta-estradiol, progesterone, recombinant hCG, and IFN-gamma as well as an IFN-gamma R-blocking antibody.

MAIN OUTCOME MEASURE(S)

We analyzed IFN-gamma R and the phosphorylation of signal transducer and activator of transcription 1 (STAT-1) by flow cytometry. We measured IFN-gamma R and interferon response factor 1 (IRF-1) mRNA using semiquantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR).

RESULT(S)

The IFN-gamma R is up-regulated in human ESCs during decidualization without affecting the phosphorylation of STAT-1. Stimulation of IRF-1 by IFN-gamma is reduced in decidualized ESCs. We found that hCG neither regulates the IFN-gamma R nor its signaling pathway.

CONCLUSION(S)

These results show an inverse regulation of the IFN-gamma R and its signaling response via STAT-1 and IRF-1 in human ESCs during decidualization. The early embryonic signal hCG has no effect on this process. This mechanism may finely modulate the reactivity of ESCs to IFN-gamma-mediated signals from immune cells at the implantation site.