The role of transcriptomic biomarkers of endometrial receptivity in personalized embryo transfer for patients with repeated implantation failure

Correlation of MicroRNA-31 with Endometrial Receptivity in Patients with Repeated Implantation Failure of In Vitro Fertilization and Embryo Transfer

OBJECTIVE

This trial probed the correlation between miR-31 expression and endometrial receptivity (ER) in patients with repeated implantation failure (RIF) of in vitro fertilization and embryo transfer (IVF-ET).

METHODS

A retrospective study of 80 infertility patients who underwent IVF-ET assisted conception treatment were divided into RIF group and normal pregnancy group (control group) according to the pregnancy outcome after embryo transfer. General information of both groups was collected. Endometrial tissues were collected in the middle luteal phase of the menstrual cycle before IVF-ET. miR-31 levels in endometrial tissues were measured, and endometrial tolerance indicator pulsatility index (PI), resistance index (RI), and endometrial thickness (Em) were detected. The correlation between endometrial miR-31 levels and ER indices was evaluated by Pearson method. ROC curves were utilized to analyze the efficacy of miR-31 in predicting RIF occurrence. The influencing factors of RIF were analyzed by binary Logistic regression.

RESULTS

RIF patients had increased miR-31 expression level and endometrial tolerance indicator PI, and RI while decreased Em (p < 0.05). miR-31 in RIF patients was positively correlated with PI and RI, and negatively correlated with Em (p < 0.05). The area under the curve for miR-31 to predict the occurrence of RIF was 0.899, with a sensitivity of 0.750 and a specificity of 0.950. PI, RI, and miR-31 were risk factors for developing RIF in IVF-ET women, and Em was a protective factor (p < 0.05).

CONCLUSION

miR-31 in RIF patients is positively correlated with PI and RI, and negatively correlated with Em.

Endometrial Thickness Change in Response to Progesterone is Associated with Ongoing Pregnancy Rate in Women with Treated Intrauterine Adhesion - A Prospective Cohort Study

Objective

This study aimed to investigate whether endometrial thickness (EmT) change prognosticates the ongoing pregnancy rate (OPR) in hormonally prepared frozen-thawed embryo transfers (FETs) in women with treated intrauterine adhesion (IUA).

Methods

We prospectively examined 261 FET cycles in women with IUA. Ultimately, 156 patients were included in the final analysis. The primary outcome was OPR. The association between the EmT change ratio and OPR, as well as the relationship between the EmT change and serum hormone concentration, was analyzed.

Results

The intraclass correlation coefficient for repeated EmT measurements was 0.944 (95% CI: 0.933-0.954, P < 0.001). Subdividing by the expansion cutoff from 5% to 15%, the 10% expansion group had the highest OPR with optimal sensitivity and specificity. Regarding the baseline characteristics, there were no statistically significant differences between the two groups. Nevertheless, the OPR increased significantly in cycles with endometrial expansion ≥ 10% compared to those with no expansion (55.3% vs 26.3%, P=0.001). The difference was still significant after adjustment between the two groups (adjusted OR, 3.74; 95% CI 1.68-8.34, P=0.001). No correlation was found between the EmT change and serum hormone concentrations.

Conclusion

Endometrial expansion was significantly correlated with higher OPR in women with treated IUA in the hormonal protocol for FET.

Lipopolysaccharide alters cell communication at the maternal-fetal interface revealed by single-cell RNA-sequencing

Embryo implantation is a decisive process in pregnancy that highly relies on effective cell communication at the maternal-fetal interface. Embryo implantation failure is frequently caused by gram-negative bacterial infection, therefore, this study aimed to investigate the effect of Lipopolysaccharides (LPS)-induced inflammation on cellular composition, cell-cell interaction and key signaling pathways at the maternal-fetal interface using Single-cell RNA-Sequence (scRNA-Seq). LPS exposure significantly up-regulated the expression of pro-inflammatory cytokines, CCL-2, TNF-α, and IL-1β in maternal-fetal interface tissues as well as triggered the recruitment of neutrophils, monocytes and eosinophils into peripheral blood. scRNA-Seq revealed endometrial epithelial cells (EpCs), stromal cells (ESCs), Fibroblasts (FiCs) and 15 other cell types. LPS administration significantly shifted the cellular proportions, increased populations of immune cells and fibroblasts while decreased ESCs and EpCs. Cellular differentiation indicated that all ESCs originated from ESC8 while ESC2 and 7 were the most differentiated ESC subtypes. Likewise, cellular communication demonstrated notable differences, reversed interactions were observed exclusively on the LPS exposure between luminal epithelial (LE) and glandular epithelial (GE) cells. ESC8 was inactive in the control group but exhibited robust interactions in the LPS group. Furthermore, the communication analysis predicted significant disruptions in the signaling pathways: Embryo-maternal communications (DHEA, BMP, LIFR, EDN, and NEGR pathways). Endometrial stromal-epithelial crosswalks (5αP, CAECAM, DHEAS and HH pathways) and Endometrial stromal-immune cell interactions (EGF and NCAM pathways). Our findings suggest that signaling pathways are essential for maternal-fetal communication. The disruption of the pathways in response to LPS may provide new molecular targets for diagnosing and treating implantation failure and recurrent pregnancy loss.

The Impact of BMI on PCOS Patients and Transcriptome Profiling and Bioinformatic Analysis of Granulosa Cells in PCOS Patients with High and Low BMI

PURPOSE

To explore the impact of high body mass index (BMI) on the embryo quality and clinical outcomes of polycystic ovary syndrome (PCOS) patients, and the possible genes involved.

METHODS

Patients who underwent in-vitro fertilization (IVF) treatment and embryo transfer in our center from November 2014 to September 2023, were divided into low BMI PCOS (LBP) group, high BMI PCOS (HBP) group, and high BMI control (HBC) group. Transcriptome sequencing was performed in eight PCOS patients' granulosa cells (GCs).

RESULTS

A total of 812 IVF/intracytoplasmic sperm injection (ICSI) cycles in the embryo part; and 489 fresh, 634 frozen-warmed embryo transfer (FET) cycles from the clinical part were included. The ICSI normal fertilization rate of HBP group was decreased compared to LBP and HBC groups (p = 0.013&0.008). The IVF blastocyst development rate in HBP group was lower than LBP group (p = 0.01). The preterm birth rate in HBP group was higher than in LBP (30.66% vs. 16.48%, p = 0.041) and HBC groups (30.66% vs. 11.34%, p = 0.002), the adjusted OR (AOR) of preterm birth and BMI was 1.124 (p = 0.023) in FET cycles. Transcriptome sequencing result of GCs showed that differentially expressed miRNAs/lncRNA/circRNA/mRNAs in two PCOS groups were 61, 450, 83, and 568, respectively. The hub genes analysis, enrichment analysis and competing endogenous RNA network revealed that cell cycle, oocyte maturation, systemic lupus erythematosus, oxidative phosphorylation, and mitogen-activated protein kinases (MAPK) signaling pathways had important roles in the embryo development and pregnancy process.

CONCLUSIONS

The combined effect of PCOS and obesity reduced oocyte quality and embryonic development potential, finally led to poorer clinical outcomes.

Establishment and application of an RNA-seq-based predictive model for the hourly precision window of implantation (WOI) in patients with recurrent implantation failure

PURPOSE

This study aims to establish a single-time point RNA-sequencing-based endometrial receptivity test (rsERT) to provide hourly precision of endometrial WOI for patients with recurrent implantation failure (RIF).

METHODS

A two-phase study was conducted. In the first phase, a total of 70 patients with successful intrauterine pregnancy after personalized embryo transfer (pET) guided by three-time points rsERT were recruited for modified rsERT. Another 21 patients who underwent the prototype of single-time point rsERT were further included for optimization. In the second phase, another cohort of 574 patients with RIF that was recruited and assigned to the experimental group underwent pET guided by the modified rsERT (n = 261) or the control group underwent conventional ET (n = 313). The positive β-human chorionic gonadotropin (β-hCG), intrauterine pregnancy rate (IPR), implantation rate (IR), ongoing pregnancy rate, and live birth rate of the two groups were analyzed.

RESULT

The modified rsERT provided an hour-based predictive result of endometrial WOI with an average accuracy of 94.51% and sensitivity and specificity of 92.73% and 96.29%, respectively. The positive β-hCG, IPR, IR, ongoing pregnancy rate, and live birth rate of the experimental group were significantly different from those in the control group. After propensity score matching (PSM) control for the confounders, positive β-hCG, IR, and early spontaneous abortion rate showed significant differences.

CONCLUSION

The modified rsERT provided hourly precision WOI prediction using a single-time point endometrial biopsy and pregnancy outcomes were significantly improved, providing an enhanced endometrial receptivity test as an alternative requiring only a single-time point sampling for patients with RIF.

Novel endometrial receptivity test increases clinical pregnancy and live birth rates in patients with recurrent implantation failure: Secondary analysis of a prospective clinical trial

OBJECTIVES

This study aimed to evaluate the efficiency of endometrial receptivity testing (ERT) in improving pregnancy outcomes for patients with recurrent implantation failure (RIF), and to investigate the incidence of implantation window displacement.

METHODS

Conducted between April 2021 and August 2022, at a university-affiliated reproductive center, the study included 85 RIF patients who had failed to achieve pregnancy after three embryo transfers. As part of a multicenter prospective cohort study (ChiCTR2200059342), 45 patients underwent ERT-guided frozen single blastocyst transfer, while 40 received standard treatment without ERT. Endometrial preparation was performed using a hormone replacement therapy (HRT) protocol in the cycle preceding transfer. Endometrial sampling for ERT, including RNA sequencing, artificial intelligence, and discriminant analysis of endometrial receptivity, was conducted on day 5 after progesterone administration to determine the implantation window. The same HRT protocol was used in the transfer cycle, with embryo transfer timed according to the ERT-calculated window.

RESULTS

Our data showed that 28.07% of patients exhibited a displaced implantation window, all characterized by pre-receptive endometrium. The ERT group had significantly higher clinical pregnancy rates (57.78% vs. 35.00%, p = 0.036) and live birth rates (53.33% vs. 30.00%, p = 0.030) compared with the non-ERT group.

CONCLUSION

Our findings suggest that approximately one-third of RIF occurrences may be due to endometrial factors, and ERT-guided personalized embryo transfer significantly improves pregnancy outcomes, underscoring its value in reproductive medicine.

Optimized gene-enhanced ERA improves in vitro fertilization outcomes in patients with repeated implantation failure: A meta-analysis

BACKGROUND

Assisted reproductive technology still presents a significant challenge when it comes to repeated implantation failure (RIF). To address this issue, personalized embryo transfer (pET) has been suggested as a potential solution. pET involves guiding the embryo transfer process based on an analysis of endometrial receptivity, known as endometrial receptivity analysis (ERA). However, the clinical value of this approach remains uncertain.

METHODS

We conducted a comprehensive analysis of 14 studies pertaining to pET guided by ERA in patients with RIF. The outcomes evaluated in these studies encompassed the clinical pregnancy rate (CPR), implantation rate, and live birth rate (LBR). In addition, we performed subgroup analysis by considering different definitions of RIF and utilizing various ERA techniques, such as traditional and optimized gene-enhanced approaches.

RESULTS

In general, the utilization of ERA-guided pET did not have a substantial impact on CPR (relative risk [RR], 1.25 [95% CI, 0.85-1.84]), implantation rate (RR, 1.59 [95% CI, 0.89-2.82]), or LBR (RR, 1.55 [95% CI, 0.96-2.50]) compared with standard transfer. However, the implementation of optimized gene-enhanced ERA methods demonstrated significant enhancements in CPR (RR, 2.04 [95% CI, 1.53-2.72]) and LBR (RR, 2.61 [95% CI, 1.58-4.31]).

CONCLUSION

While ERA-guided pET shows limited efficacy in improving pregnancy outcomes in patients with RIF, there lies potential in optimizing gene-enhanced ERA techniques to augment both clinical pregnancy rates and LBRs.

Factors influencing endometrial receptivity in women with recurrent implantation failure

BACKGROUND

Embryo implantation involves two key elements: a good quality embryo and receptive endometrium. Endometrial receptivity abnormalities are known as one of the possible causes of recurrent implantation failure (RIF), especially when the embryo is euploid. This study was aimed to evaluate the impact of age and other clinical factors on endometrial receptivity in women with RIF.

METHODS

68 women with RIF (defined as at least three unsuccessful transfers of good quality embryo of at least 1BB category of blastocysts) and 49 controls (women undergoing IVF treatment because of idiopathic infertility or male factor) were included to the study. After preparation of the endometrium by the hormone replacement therapy endometrial biopsies were taken from each patient and sequenced with beREADY test TAC targeting 67 biomarker genes for endometrial receptivity. Depending on the test result patients were classified into one of four different groups: pre-receptive (n = 16), early-receptive (n = 54), receptive (n = 44) and late-receptive (n = 3).

RESULTS

In women with RIF pre-receptive endometrium has been detected substantially more often than in controls - 13 (19,1%) vs. 3 (6,1%) patients (p = 0,043). Early-receptive endometrium was diagnosed in the majority of patients with idiopathic infertility - 12 (66.7%) vs. 6 (33.3%) women (p = 0.042) and with polycystic ovary syndrome (PCOS) - 12 (70,6%) vs. 3 (17.7%) women (p = 0,0447). We found significant association between abnormal endometrial receptivity and patient's age and duration of infertility. Young women were diagnosed significantly more often as normal or late-receptive, whereas older women with longer history of infertility as early-receptive and pre-receptive.

CONCLUSIONS

In patients with RIF in comparison to other women undergoing IVF procedures, patient's age and infertility duration are the most important factors related to endometrial receptivity abnormalities, indicating that older women with a longer history of infertility may benefit the most from endometrial receptivity testing.

TRIAL REGISTRATION

Not applicable.

Time-series single-cell transcriptomic profiling of luteal-phase endometrium uncovers dynamic characteristics and its dysregulation in recurrent implantation failures

Understanding human endometrial dynamics in the establishment of endometrial receptivity remains a challenge, which limits early diagnosis and treatment of endometrial-factor infertility. Here, we decode the endometrial dynamics of fertile women across the window of implantation and characterize the endometrial deficiency in women with recurrent implantation failure. A computational model capable of both temporal prediction and pattern discovery is used to analyze single-cell transcriptomic data from over 220,000 endometrial cells. The time-series atlas highlights a two-stage stromal decidualization process and a gradual transitional process of the luminal epithelial cells across the window of implantation. In addition, a time-varying gene set regulating epithelium receptivity is identified, based on which the recurrent implantation failure endometria are stratified into two classes of deficiencies. Further investigation uncovers a hyper-inflammatory microenvironment for the dysfunctional endometrial epithelial cells of recurrent implantation failure. The holistic characterization of the physiological and pathophysiological window of implantation and a computational tool trained on this temporal atlas provide a platform for future therapeutic developments.

Ectopic pregnancy is associated with increased risk of displaced implantation window: a retrospective study

BACKGROUND

To evaluate the risk factors associated with WOI (window of implantation) displacement based on ERT (endometrial receptivity test), and to confirm the association of ectopic pregnancy with WOI displacement.

METHODS

This is a retrospective study at the Reproductive Medicine Center of Xiangya Hospital from January 2020 to April 2024, consisting of 934 patients who performed ERT. The patients underwent 3771 assisted reproductive technology (ART) cycles and 2629 embryo transfer (ET) cycles, with each patient experiencing at least one implantation failure. The study utilized generalized estimation equation (GEE) models to examine factors associated with WOI displacement, adjusting for confounding factors like age, body mass index (BMI), and infertility type. Non-linear relationships between age or BMI with WOI displacement were explored using generalized additive models (GAM) with thresholds detected by segmented regression.

RESULTS

Among the patients, 60.17% were in the receptive phase, 39.40% in the pre-receptive phase, and 0.43% in the post-receptive phase. Ectopic pregnancy history increased the risk of WOI displacement by 62% (aOR 1.62, 95%CI 1.03-2.53, P = 0.035), patients over 35 years old had a 50% higher risk of WOI displacement compared to patients under 34 (aOR 1.50, 95% CI 1.12-2.00, P = 0.007). Secondary infertility showed a 26% lower risk of WOI displacement than primary infertility without statistical significance (aOR 0.74 95% CI 0.54-1.02, P = 0.062). BMI ≥ 22 kg/m2 was associated with a 25% increased risk of WOI displacement without statistical significance (aOR 1.25, 95% CI 0.94-1.67, P = 0.12).

CONCLUSION

Ectopic pregnancy and advanced age (≥ 35) are significantly associated with increased risk of WOI displacement. Primary infertility and higher BMI (≥ 22 kg/m2) tend to increase the risk of WOI displacement though without statistical significance.

CLINICAL TRIAL NUMBER

Not applicable.

Multi-omics PGT: re-evaluation of euploid blastocysts for implantation potential based on RNA sequencing

STUDY QUESTION

In addition to chromosomal euploidy, can the transcriptome of blastocysts be used as a novel predictor of embryo implantation potential?

SUMMARY ANSWER

This retrospective analysis showed that based on differentially expressed genes (DEGs) between euploid blastocysts which resulted and did not result in a clinical pregnancy, machine learning models could help improve implantation rates by blastocyst optimization.

WHAT IS KNOWN ALREADY

Embryo implantation is a multifaceted process, with implantation loss and pregnancy failure related not only to blastocyst euploidy but also to the intricate dialog between blastocyst and endometrium. Although in vitro studies have revealed the characteristics of trophectoderm (TE) differentiation in implanted blastocysts and the function of TE placentation at the implantation site, the precise molecular mechanisms of embryo implantation and their clinical application remain to be fully elucidated.

STUDY DESIGN, SIZE, DURATION

This study involved 102 patients who underwent 111 cycles for preimplantation genetic testing for aneuploidies (PGT-A) between March 2022 and July 2023.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included 412 blastocysts biopsied at Day 5 [D5] or Day 6 [D6] for patients who underwent PGT-A. The biopsy lysates were split and subjected to DNA and RNA sequencing (DNA- and RNA-seq). One part was used for PGT-A to detect DNA copy number variations, whereas the other part was assessed simultaneously by RNA-seq to determine the transcriptome characteristics. To validate the reliability and accuracy of RNA-seq obtained from this strategy, we initially analyzed the transcriptome of blastocysts with chromosomal aneuploidies. Subsequently, we compared the transcriptomic features of blastocysts with different rates of formation (D5 vs D6) and investigated the network of interactions between key blastulation genes and the receptive endometrium. Then to evaluate the implantation potential of euploid blastocysts, we identified DEGs between euploid blastocysts that resulted in clinical pregnancy (defined as the presence of a gestational sac detected by ultrasound after 5 weeks) and those that did not. These DEGs were then employed to construct a predictive model for optimizing blastocyst selection.

MAIN RESULTS AND THE ROLE OF CHANCE

The successful detection rate of PGT-A was remarkably high at 99.8%. The RNA data may infer aneuploidy for both trisomy and monosomy. Between the euploid blastocysts that formed on D5 and D6, 187 DEGs were predominantly involved in cell differentiation for embryonic placenta development, the PPAR signaling pathway, and the Notch signaling pathway. These D5/D6 DEGs also exhibited a functional dialog with the receptive phase endometrium-specific genes through protein-protein interaction networks, indicating that the embryo undergoes further differentiation for post-implantation development. Furthermore, a modeling strategy using 280 DEGs between blastocysts leading to successful clinical pregnancies or failing to produce clinical pregnancies was implemented to refine the euploid embryo optimization, achieving areas under the curves of 0.88, 0.71, and 0.84 for the random forest (RF), support vector machine, and linear discriminant analysis models, respectively. Finally, a retrospective analysis of 83 transferred euploid blastocysts using the RF model identified three types of euploid embryos with a decreasing trend in implantation potential. Notably, the implantation rate of the good group was significantly higher than that of the moderate group (88.6% vs 50.0% P = 0.001) and that of the moderate group was higher than that of the poor group (50.0% vs 20.8%, P = 0.035).

LIMITATIONS, REASONS FOR CAUTION

The sample size was insufficient; thus, a prospective study is needed to verify the clinical effectiveness of the above model. Because we did not analyze blastocysts that led only to biochemical pregnancies but failed clinical pregnancies separately, our classification system still must be modified to screen these embryos.

WIDER IMPLICATIONS OF THE FINDINGS

Transcriptomic analysis of blastocysts offers a novel approach for predicting embryo implantation potential, which can be utilized to optimize clinical embryo selection. The ranking system may be effective in reducing the times and costs involved in achieving a clinical pregnancy.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the "Pioneer" and "Leading Goose" R&D Program of Zhejiang (No. 2023C03034), the National Natural Science Foundation of China (82101709), and the National Key Research and Development Program for Young Scientists of China (No. 2022YFC2702300). The authors state no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Development of a New Personalized Molecular Test Based on Endometrial Receptivity and Maternal-Fetal Dialogue: Adhesio

Successful embryo implantation relies on a receptive endometrium and a maternofetal dialogue. Abnormal receptivity is a common cause of implantation failure in assisted reproductive techniques. This study aimed to develop a novel transcriptomic-based diagnostic assay, Adhesio, for assessing endometrial receptivity and guiding personalized embryo transfer. Adhesio was developed based on an initial dataset of 74 endometrial biopsies. Two types of biopsy samples were involved: 45 endometrial biopsies collected during the optimal theoretical window of implantation (WOI) and 29 endometrial biopsies which cells have been cultured with or without an autologous embryo. Microarray analysis was performed to identify differentially expressed genes associated with endometrial receptivity and selected candidate genes were assessed using quantitative real-time polymerase chain reaction (RT-qPCR) on biopsy samples. Statistical analyses were conducted to assess the performance and accuracy of Adhesio. The microarray analysis identified three distinct clusters of endometrial samples with differential gene expression patterns. Cluster 1 exhibited 1717 differentially expressed genes involved in biological processes associated with endometrial receptivity. A specific transcriptomic signature of 60 genes associated with endometrial co-culture was obtained using class prediction approach. Thereafter, an original panel of 10 genes was selected as potential biomarkers for endometrial receptivity based on their expression profiles in both endometrial biopsies and co-cultured cells. This article outlines the methodology employed to develop Adhesio, a test that assesses endometrial receptivity using an original panel of 10 genes. These genes are not only involved during the WOI but are also influenced by the maternal-fetal dialogue.

Improving pregnancy outcomes in patients with recurrent implantation failure: The power of RNA-seq-based endometrial receptivity testing

To evaluate whether RNA-seq-based endometrial receptivity testing (rsERT) can improve pregnancy outcomes in personalized frozen-thawed embryo transfer (pFET) during hormone replacement therapy (HRT) cycles among patients with recurrent implantation failure (RIF). We conducted a retrospective cohort study involving 98 RIF patients undergoing HRT for FET. The experimental group consisted of 58 patients who underwent pFET after rsERT, while the control group included 40 patients who refused rsERT and underwent conventional ET. We recorded and examined the subsequent pregnancy outcomes from all cycles. The results of rsERT revealed that 67.24% of the experimental group were out of the "window of implantation" (WOI), with all cases showing a delay. The HCG-positive rate, implantation rate, and clinical pregnancy rate (CPR) in the experimental group were significantly higher than those in the control group, at 75.86% versus 50.00% (P = .030), 56.38% versus 31.43% (P = .002), and 68.97% versus 47.50% (P = .033), respectively. Our study demonstrated that utilizing rsERT technology to guide pFET in HRT cycles significantly enhances implantation and CPRs in RIF patients. Importantly, our findings confirm the effectiveness of rsERT technology and establish a scientific rationale for personalized reproductive medical interventions.

Evaluation of NKT Cell Percentage and Function and Its Relationship with Serum IFN-γ and Vitamin D Levels in Women with Recurrent Spontaneous Abortion and Recurrent Implantation Failure

Background

Mothers experiencing recurrent spontaneous abortion (RSA) along with repeated implantation failures (RIF) could potentially have abnormalities in their immune systems. Vitamin D is known as a crucial immunomodulatory agent. This study aimed to assess the ratio of Natural Killer T-cells (NKTs) and the correlation between this ratio with serum vitamin D levels among women with RSA and RIF.

Methods

In this research, blood samples were collected from both patients and a group of healthy individuals. The flow cytometry technique was used to determine the proportion of NKT and activated NKT cells. Additionally, Vitamin D and IFN-γ levels were measured using the ELISA technique.

Results

The mean ratio of NKT cells and IFN-γ levels increased significantly in those women with RSA relative to our healthy control group [(P < 0.018) and (p < 0.031), respectively]. Nevertheless, women in the RIF and control groups did not show any significant differences. Serum vitamin D levels significantly decreased in RIF (p < 0.04) and RSA (p < 0.01) groups relative to the control group.

Conclusions

It was found that increasing ratio as well as inflammatory activity of NKT cells correlated with repeated miscarriage. Reduced vitamin D levels could cause immune system disorder along with pregnancy complications.

Personalized embryo transfer guided by rsERT with hourly precision improves pregnancy outcomes in patients with a receptive window of implantation: a pilot study

PURPOSE

To investigate whether personalized embryo transfer (pET) predicted by a modified RNA-sequencing-based endometrial receptivity test (rsERT) model can improve intrauterine pregnancy rate (IPR) in patients with a receptive window of implantation (WOI).

DESIGN

A retrospective pilot study was conducted in the Center for Reproductive Medicine, Central South University, from January 2018 to December 2023. A total of 524 patients with receptive WOI results from rsERT were assigned into two groups based on whether they underwent conventional embryo transfer (conventional ET) or pET. Patients in the conventional ET were matched with those in the pET group at a 1:1 ratio using propensity score matching (PSM).

RESULTS

Before PSM, the IPR (55.73% vs. 46.19%, P = 0.032) and implantation rate (IR) (47.51% vs. 34.03%, P = 0.000) in the pET group were significantly higher than that in the conventional ET group. However, the number and types of transferred embryos differed significantly between the two groups. After adjusting for confounding factors, IPR (57.38% vs. 44.81, P = 0.016) and IR (46.81% vs. 33.10%, P = 0.001) remained significantly higher in the pET group compared to the conventional ET group. The implantation failure rate was significantly lower in the pET group compared to controls (42.62% vs. 55.19%, P = 0.016). Additionally, the multiple-pregnancy rate was significantly higher in the pET group compared to the conventional ET group (10.29% vs. 1.68%, P = 0.001).

CONCLUSIONS

Women with receptive WOI results could benefit from the receptivity-timed pET predicted by the newly refined rsERT. These findings provide a basis for future research in precision medicine for embryo transfer.

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

Purpose

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

Methods

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

Results

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

Conclusion

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

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

BACKGROUND

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

METHODS

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

DISCUSSION

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

TRIAL REGISTRATION

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

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

Introduction

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

Methods

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

Results

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

Conclusions

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

Meta-analysis of endometrial transcriptome data reveals novel molecular targets for recurrent implantation failure

PURPOSE

Gene expression analysis of the endometrium has been shown to be a useful approach for identifying the molecular signatures and pathways involved in recurrent implantation failure (RIF). Nevertheless, individual studies have limitations in terms of study design, methodology and analysis to detect minor changes in expression levels or identify novel gene signatures associated with RIF.

METHOD

To overcome this, we conducted an in silico meta-analysis of nine studies, the systematic collection and integration of gene expression data, utilizing rigorous selection criteria and statistical techniques to ensure the robustness of our findings.

RESULTS

Our meta-analysis successfully unveiled a meta-signature of 49 genes closely associated with RIF. Of these genes, 38 were upregulated and 11 downregulated in RIF patients' endometrium and believed to participate in key processes like cell differentiation, communication, and adhesion. GADD45A, IGF2, and LIF, known for their roles in implantation, were identified, along with lesser-studied genes like OPRK1, PSIP1, SMCHD1, and SOD2 related to female infertility. Many of these genes are involved in MAPK and PI3K-Akt pathways, indicating their role in inflammation. We also investigated to look for key miRNAs regulating these 49 dysregulated mRNAs as potential diagnostic biomarkers. Along with this, we went to associate protein-protein interactions of 49 genes, and we could recognize one cluster consisting of 11 genes (consisted of 22 nodes and 11 edges) with the highest score (p = 0.001). Finally, we validated some of the genes by qRT-PCR in our samples.

CONCLUSION

In summary, the meta-signature genes hold promise for improving RIF patient identification and facilitating the development of personalized treatment strategies, illuminating the multifaceted nature of this complex condition.

When the Embryo Meets the Endometrium: Identifying the Features Required for Successful Embryo Implantation

Evaluation of the optimal number of embryos, their quality, and the precise timing for transfer are critical determinants in reproductive success, although still remaining one of the main challenges in assisted reproduction technologies (ART). Indeed, the success of in vitro fertilization (IVF) treatments relies on a multitude of events and factors involving both the endometrium and the embryo. Despite concerted efforts on both fronts, the overall success rates of IVF techniques continue to range between 25% and 30%. The role of the endometrium in implantation has been recently recognized, leading to the hypothesis that both the "soil" and the "seed" play a central role in a successful pregnancy. In this respect, identification of the molecular signature of endometrial receptivity together with the selection of the best embryo for transfer become crucial in ART. Currently, efforts have been made to develop accurate, predictive, and personalized tests to identify the window of implantation and the best quality embryo. However, the value of these tests is still debated, as conflicting results are reported in the literature. The purpose of this review is to summarize and critically report the available criteria to optimize the success of embryo transfer and to better understand current limitations and potential areas for improvement.

miR-665-Mediated Regulation of AHCYL2 and BVES Genes in Recurrent Implantation Failure

The primary goal of this investigation was to identify mRNA targets affected by dysregulated miRNAs in RIF. This was accomplished by comprehensively analyzing mRNA and miRNA expression profiles in two groups: female subjects with normal reproductive function (control, n = 5) and female subjects experiencing recurrent implantation failure (RIF, n = 5). We conducted transcriptome sequencing and small RNA sequencing on endometrial tissue samples from these cohorts. Subsequently, we validated a selection of intriguing findings using real-time PCR with samples from the same cohort. In total, our analysis revealed that 929 mRNAs exhibited differential expression patterns between the control and RIF patient groups. Notably, our investigation confirmed the significant involvement of dysregulated genes in the context of RIF. Furthermore, we uncovered promising correlation patterns within these mRNA/miRNA pairs. Functional categorization of these miRNA/mRNA pairs highlighted that the differentially expressed genes were predominantly associated with processes such as angiogenesis and cell adhesion. We identified new target genes that are regulated by miR-665, including Blood Vessel Epicardial Substance (BVES) and Adenosylhomocysteinase like 2 (AHCYL2). Our findings suggest that abnormal regulation of genes involved in angiogenesis and cell adhesion, including BVES and AHCYL2, contributes to the endometrial dysfunction observed in women with recurrent implantation failure (RIF) compared to healthy women.

Embryo Transfer Strategies for Women with Recurrent Implantation Failure During the Frozen-thawed Embryo Transfer Cycles: Sequential Embryo Transfer or Double-blastocyst Transfer?

OBJECTIVE

Both sequential embryo transfer (SeET) and double-blastocyst transfer (DBT) can serve as embryo transfer strategies for women with recurrent implantation failure (RIF). This study aims to compare the effects of SeET and DBT on pregnancy outcomes.

METHODS

Totally, 261 frozen-thawed embryo transfer cycles of 243 RIF women were included in this multicenter retrospective analysis. According to different embryo quality and transfer strategies, they were divided into four groups: group A, good-quality SeET (GQ-SeET, n=38 cycles); group B, poor-quality or mixed-quality SeET (PQ/MQ-SeET, n=31 cycles); group C, good-quality DBT (GQ-DBT, n=121 cycles); and group D, poor-quality or mixed-quality DBT (PQ/MQ-DBT, n=71 cycles). The main outcome, clinical pregnancy rate, was compared, and the generalized estimating equation (GEE) model was used to correct potential confounders that might impact pregnancy outcomes.

RESULTS

GQ-DBT achieved a significantly higher clinical pregnancy rate (aOR 2.588, 95% CI 1.267-5.284, P=0.009) and live birth rate (aOR 3.082, 95% CI 1.482-6.412, P=0.003) than PQ/MQ-DBT. Similarly, the clinical pregnancy rate was significantly higher in GQ-SeET than in PQ/MQ-SeET (aOR 4.047, 95% CI 1.218-13.450, P=0.023). The pregnancy outcomes of GQ-SeET were not significantly different from those of GQ-DBT, and the same results were found between PQ/MQ-SeET and PQ/MQ-DBT.

CONCLUSION

SeET relative to DBT did not seem to improve pregnancy outcomes for RIF patients if the embryo quality was comparable between the two groups. Better clinical pregnancy outcomes could be obtained by transferring good-quality embryos, no matter whether in SeET or DBT. Embryo quality plays a more important role in pregnancy outcomes for RIF patients.

Personalized embryo transfer based on RNA sequencing endometrial receptivity test in repeated implantation failure patients: artificial cycle versus natural cycle

INTRODUCTION

Embryo implantation provides an efficient way for patients with repeated implantation failure (RIF) to achieve pregnancy. The aim of this study is to compare the implantation outcomes of RIF patients in artificial cycle to those in natural cycle, both were treated with RNA sequencing endometrial receptivity test (rsERT) based personalized embryo implantation.

METHODS

The endometrial receptivity (ER) analysis was performed using rsERT followed by personalized embryo transfer at optimal window of implantation (WOI). The implantation rate (IR), clinical pregnancy rate (CPR) and live birth rate (LBR) were calculated. The expression levels of biomarkers involved in pregnancy process in the patients detected as in receptivity status were also analyzed.

RESULTS

The rsERT shown that 44.8% (natural cycle) and 47.8% (artificial cycle) patients were in non-receptive status, which indicated a WOI displacement. After personalized embryo transfer, the IR of patients in artificial cycle was higher than those in natural cycle (52.2% vs 27.6%). The expressions of FKBP52, MUC1 and LPAR3 were significantly lower in artificial cycle than in natural cycle.

CONCLUSION

Using artificial cycle for personalized embryo transfer based on rsERT may yield better pregnancy outcomes for RIF patients. A gene expression analysis of FKBP52, MUC1 and LPAR3 provided a potential way to increase implantation outcomes for RIF patients.

Factors affecting the ongoing pregnancy rate in women with repeated implantation failure undergoing an endometrial receptivity array

OBJECTIVE

In this retrospective study, we analyzed factors influencing the ongoing pregnancy rate (PR) in women with repeated implantation failure (RIF) undergoing embryo transfer with endometrial receptivity array (ERA).

METHODS

Eighty-three consecutive personalized embryo transfers (pETs) with ERA, from 54 women with RIF, were selected from June 2020 to April 2022. Vitrified blastocyst transfer was timed based on ERA results.

RESULTS

The ongoing PR per pET was 33.7%. Using ERA, the endometrium was identified as pre-receptive in 26 cycles, early receptive in 25 cycles, receptive in 31 cycles, and late receptive in one cycle. With cycles categorized into three receptivity phases (pre-receptive, early receptive, or receptive), no significant differences were found in the clinical PR (27.3%, 55.6%, and 40%, respectively) or ongoing PR (9.1%, 55.6%, and 40%, respectively) after a single blastocyst transfer. Similarly, no significant differences were observed in the clinical PR or ongoing PR after the transfer of two or more blastocysts. Among women with ongoing pregnancy relative to those without, age at first pET was significantly lower (35 years vs. 39 years, p=0.001), while blastocyst score (23 vs. 18, p=0.012) and the proportion of blastocyst scores >18 (71.4% vs. 38.9%, p=0.005) were significantly higher. In multiple logistic regression analysis, the woman's age (odds ratio [OR], 0.814; 95% confidence interval [CI], 0.706 to 0.940; p=0.005) and blastocyst score >18 (OR, 3.052; 95% CI, 1.075 to 8.665; p=0.036) were identified as significant factors influencing ongoing pregnancy.

CONCLUSION

In pET with ERA, ongoing pregnancy was closely associated with woman's age and blastocyst quality.

Integrated treatment guided by RNA-seq-based endometrial receptivity assessment for infertility complicated by MEN1

Background

Preimplantation genetic testing (PGT) serves as a tool to avoid genetic disorders in patients with known genetic conditions. However, once a selected embryo is transferred, implantation success is attained independent of embryo quality. Using PGT alone is unable to tackle implantation failure caused by endometrial receptivity (ER) abnormalities in these patients.

Methods

We validated our newly developed RNA-seq-based ER test (rsERT) in a retrospective cohort study including 511 PGT cycles and reported experience in treating an infertile female patient complicated by multiple endocrine neoplasia type 1 (MEN1).

Results

Significant improvement in the clinical pregnancy rate was found in the performed personalized embryo transfer (pET) group (CR, 69.7%; P = 0.035). In the rare MEN1 case, pET was done according to the prediction of the optimal time of window of implantation after unaffected blastocysts were obtained by PGT-M, which ultimately led to a healthy live birth. However, none of the mRNA variants identified in the patient showed a strong association with the MEN1 gene.

Conclusions

Applying the new rsERT along with PGT improved ART outcomes and brought awareness of the importance of the ER examination in MEN1 infertile female patients. MEN1-induced endocrine disorder rather than MEN1 mutation contributes to the ER abnormality.

Trial Registration

Reproductive Medicine Ethics Committee of Xiangya Hospital Registry No.: 2022010.

An endometrium of type C along with an endometrial thickness of < 8 mm are risk factors for ectopic pregnancy after stimulated cycles with fresh embryo transfer

BACKGROUND

The study investigated whether specific ultrasonographically observed endometrial features (including endometrium type and thickness) were linked to ectopic pregnancy after stimulated cycles with fresh embryo transfer.

METHOD

Of 6246 pregnancy cycles after fresh embryo transfer, 6076 resulted in intrauterine pregnancy and 170 in ectopic pregnancy. The primary outcome of the study was ectopic pregnancy, with the main variables being endometrium type and endometrial thickness. Univariate and subsequent multiple-stepwise logistic regression analyses were used to identify the risk factors of ectopic pregnancy.

RESULTS

1. Compared with patients with an endometrial thickness ≥ 8 mm, the adjusted odds ratio for those with an endometrial thickness < 8 mm was 3.368 (P < 0.001). The adjusted odds ratio for women with a type-C endometrium was 1.897 (P = 0.019) compared with non-type C. 2. A larger dose of gonadotropin used during controlled ovarian hyperstimulation was a protective factor against ectopic pregnancy (P = 0.008). 3. The GnRH antagonist protocol (P = 0.007) was a risk factor for ectopic pregnancy, compared with the use of GnRH agonists.

CONCLUSION

(1) An endometrial thickness < 8 mm coupled with a type C endometrium significantly increased the risk of ectopic pregnancy after fresh embryo transfer. (2) A thin endometrial thickness and a type C endometrium could be further related to an abnormal endometrial receptivity/peristaltic wave. (3) Patients at a high risk of ectopic pregnancy should therefore be given special attention, with early diagnosis during the peri-transplantation period may assist in the prevention of ectopic pregnancy.

Endometrial fluid biomarkers and their potential as predictors of successful embryo implantation

Background

Embryo implantation is a complex biological process which requires synchronized dialogue between the receptive endometrium and the blastocyst. The endometrium, however, is only receptive to embryo implantation for a very short period. Recurrent implantation failure (RIF) is a major challenge in assisted reproductive techniques mainly due to impaired receptivity, but there is still a need for a reliable and valid clinical test to assess endometrial receptiveness, especially at embryo transfer time. The aim of this review is to investigate what is currently known about the contribution of endometrial fluid (EF) to endometrial receptivity by identifying its potential biomarkers.

Methods

This study involved an extensive search of the electronic databases PubMed and Cochrane, covering the period from 2011 to 2022. A combination of Medical Subject Headings with the terms 'endometrial fluid' and 'embryo implantation' was used.

Results

Several different proteins presented in the endometrial cavity fluid have been described but the most consistent as potential biomarkers were Proprotein Convertase 6 (PC6), Vascular Endothelial Growth Factor (VEGF), PIGF (Placental growth factor), β3 integrin, Colony Stimulating Factor-3 (CSF-3), Leukaemia inhibitory factor (LIF), glycodelin and extracellular vesicles (EVs).

Conclusions

Strong indicators support the use of uterine fluid collection as a non-invasive tool for receptivity assessment. Therefore, it could improve outcomes of assisted reproductive techniques.

Targeted gene expression profiling for accurate endometrial receptivity testing

Expressional profiling of the endometrium enables the personalised timing of the window of implantation (WOI). This study presents and evaluates a novel analytical pipeline based on a TAC-seq (Targeted Allele Counting by sequencing) method for endometrial dating. The expressional profiles were clustered, and differential expression analysis was performed on the model development group, using 63 endometrial biopsies spanning over proliferative (PE, n = 18), early-secretory (ESE, n = 18), mid-secretory (MSE, n = 17) and late-secretory (LSE, n = 10) endometrial phases of the natural cycle. A quantitative predictor model was trained on the development group and validated on sequenced samples from healthy women, consisting of 52 paired samples taken from ESE and MSE phases and five LSE phase samples from 31 individuals. Finally, the developed test was applied to 44 MSE phase samples from a study group of patients diagnosed with recurrent implantation failure (RIF). In validation samples (n = 57), we detected displaced WOI in 1.8% of the samples from fertile women. In the RIF study group, we detected a significantly higher proportion of the samples with shifted WOI than in the validation set of samples from fertile women, 15.9% and 1.8% (p = 0.012), respectively. The developed model was evaluated with an average cross-validation accuracy of 98.8% and an accuracy of 98.2% in the validation group. The developed beREADY screening model enables sensitive and dynamic detection of selected transcriptome biomarkers, providing a quantitative and accurate prediction of endometrial receptivity status.

Endometrial proteomic profile of patients with repeated implantation failure

Introduction

Successful embryo implantation, is the initiating step of pregnancy, relies on not only the high quality of the embryo but also the synergistic development of a healthy endometrium. Characterization and identification of biomarkers for the receptive endometrium is an effective method for increasing the probability of successful embryo implantation.

Methods

Endometrial tissues from 22 women with a history of recurrent implantation failure (RIF) and 19 fertile controls were collected using biopsy catheters on 7-9 days after the peak of luteinizing hormone. Differentially expressed proteins (DEPs) were identified in six patients with RIF and six fertile controls using isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomics analysis.

Results

Two hundred and sixty-three DEPs, including proteins with multiple bioactivities, such as protein translation, mitochondrial function, oxidoreductase activity, fatty acid and amino acid metabolism, were identified from iTRAQ. Four potential biomarkers for receptive endometrium named tubulin polymerization-promoting protein family member 3 TPPP3, S100 Calcium Binding Protein A13 (S100A13), 17b-hydroxysteroid dehydrogenase 2 (HSD17B2), and alpha-2-glycoprotein 1, zinc binding (AZGP1) were further verified using ProteinSimple Wes and immunohistochemical staining in all included samples (n=22 for RIF and n=19 for controls). Of the four proteins, the protein levels of TPPP3 and HSD17B2 were significantly downregulated in the endometrium of patients with RIF.

Discussion

Poor endometrial receptivity is considered the main reason for the decrease in pregnancy success rates in patients suffering from RIF. iTRAQ techniques based on isotope markers can identify and quantify low abundance proteomics, and may be suitable for identifying differentially expressed proteins in RIF. This study provides novel evidence that TPPP3 and HSD17B2 may be effective targets for the diagnosis and treatment of non-receptive endometrium and RIF.

Transcriptomic analysis of mid-secretory endometrium reveals essential immune factors associated with pregnancy after single euploid blastocyst transfer

PURPOSE

Implantation is a limiting factor for treatment success in assisted reproduction. Both embryonic and endometrial factors contribute to implantation. Embryonic factors have often been ignored in previous studies about the role of endometrium in implantation. In this study, we sought to identify the endometrial genes associated with negative pregnancy outcomes following the transfer of a single euploid blastocyst.

METHODS

Computational analyses of the transcriptomes of mid-secretory endometria from nine pregnant and seven non-pregnant patients in a cycle preceding the transfer of a single euploid blastocyst in a vitrified-warmed cycle were performed.

RESULTS

Principal component analysis of two reported endometrial receptivity gene sets showed close clustering of the pregnant and non-pregnant samples. Differential gene expression analysis and co-expression module analysis identified 131 genes associated with the pregnancy status. The endometrial signatures identified highlight the importance of immune and metabolic regulation in pregnancy outcome. Network analysis identified 20 hub genes that could predict pregnancy outcomes with 88.9% sensitivity and 85.7% specificity. Single-cell gene expression analysis highlighted the regulation of endometrial natural killer (NK) cells, T cells, and macrophages during embryo implantation. Immune cell abundance analysis supported the dysregulation of cytotoxic immune cells in the endometria of non-pregnant women.

CONCLUSIONS

We reported the first endometrial gene signature associated with pregnancy after elimination of embryo aneuploidy and highlighted the importance of the endometrial immune microenvironment and metabolic status in pregnancy outcomes.

Can biomarkers identified from the uterine fluid transcriptome be used to establish a noninvasive endometrial receptivity prediction tool? A proof-of-concept study

BACKGROUND

Embryo implantation in a receptive endometrium is crucial for successful pregnancy. Endometrial receptivity (ER) prediction tools based on endometrial transcriptome biomarkers by endometrial biopsy have been used to guide successful embryo implantation in in vitro fertilization (IVF) patients. However, no reliable noninvasive ER prediction method has been established, and one is greatly needed. We aimed to identify biomarkers from uterine fluid transcriptomic sequencing data for establishing noninvasive ER prediction tool and to evaluate its clinical application potential in patients undergoing IVF.

METHODS

The non-invasive RNA-seq based endometrial receptivity test (nirsERT) was established by analyzing transcriptomic profile of 144 uterine fluid specimens (LH + 5, LH + 7, and LH + 9) at three different receptive status from 48 IVF patients with normal ER in combination with random forest algorithm. Subsequently, 22 IVF patients who underwent frozen-thaw blastocyst transfer were recruited and analyzed the correlation between the predicted results of nirsERT and pregnancy outcomes.

RESULTS

A total of 864 ER-associated differentially expressed genes (DEGs) involved in biological processes associated with endometrium-embryo crosstalk, including protein binding, signal reception and transduction, biomacromolecule transport and cell-cell adherens junctions, were selected. Subsequently, a nirsERT model consisting of 87 markers and 3 hub genes was established using a random forest algorithm. 10-fold cross-validation resulted in a mean accuracy of 93.0%. A small cohort (n = 22) retrospective observation shows that 77.8% (14/18) of IVF patients predicted with a normal WOI had successful intrauterine pregnancies, while none of the 3 patients with a displaced WOI had successful pregnancies. One patient failed due to poor sequencing data quality.

CONCLUSIONS

NirsERT based on uterine fluid transcriptome biomarkers can predict the WOI period relatively accurately and may serve as a noninvasive, reliable and same cycle test for ER in reproductive clinics.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR-DDD-17013375. Registered 14 November 2017, http://www.chictr.org.cn/index.aspx .

Development of an artificial intelligence based model for predicting the euploidy of blastocysts in PGT-A treatments

The euploidy of embryos is unpredictable before transfer in in vitro fertilisation (IVF) treatments without pre-implantation genetic testing (PGT). Previous studies have suggested that morphokinetic characteristics using an artificial intelligence (AI)-based model in the time-lapse monitoring (TLM) system were correlated with the outcomes of frozen embryo transfer (FET), but the predictive effectiveness of the model for euploidy remains to be perfected. In this study, we combined morphokinetic characteristics, morphological characteristics of blastocysts, and clinical parameters of patients to build a model to predict the euploidy of blastocysts and live births in PGT for aneuploidy treatments. The model was effective in predicting euploidy (AUC = 0.879) but was ineffective in predicting live birth after FET. These results provide a potential method for the selection of embryos for IVF treatments with non-PGT.

Dysregulation in Multiple Transcriptomic Endometrial Pathways Is Associated with Recurrent Implantation Failure and Recurrent Early Pregnancy Loss

Overlapping disease aetiologies associated with multiple altered biological processes have been identified that change the endometrial function leading to recurrent implantation failure (RIF) and recurrent early pregnancy loss (REPL). We aimed to provide a detailed insight into the nature of the biological malfunction and related pathways of differentially expressed genes in RIF and REPL. Endometrial biopsies were obtained from 9 women experiencing RIF, REPL and control groups. Affymetrix microarray analysis was performed to measure the gene expression level of the endometrial biopsies. Unsupervised clustering of endometrial samples shows scattered distribution of gene expression between the RIF, REPL and control groups. 2556 and 1174 genes (p value < 0.05, Fold change > 1.2) were significantly altered in the endometria of RIF and REPL patients’ group, respectively compared to the control group. Downregulation in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the differentially expressed genes (DEGs) in RIF and REPL including ribosome and oxidative phosphorylation pathways. Gene Ontology (GO) analysis revealed ribosomes and mitochondria inner membrane as the most significantly downregulated cellular component (CC) affected in RIF and REPL. Determination of the dysregulated genes and related biological pathways in RIF and REPL will be key in understanding their molecular pathology and of major importance in addressing diagnosis, prognosis, and treatment issues

Safety and feasibility of PVA formaldehyde absorbent sponge in noninvasive uterine fluid sampling and RNA sequencing

OBJECTIVES

Uterine fluid RNA can be used as a test for endometrial receptivity, but there is still no noninvasive sampling method available. The polyvinyl alcohol (PVA) formaldehyde absorbent sponge, a medical bio-absorbent sponge with good water absorption and biophilic properties, can be used to develop a new noninvasive endometrial fluid sampler. This study aims to investigate the toxicity of PVA acetal absorbent sponges on endometrial epithelial cells and its effect on RNA sequencing (RNA-Seq).

METHODS

The experimental group using PVA formaldehyde absorbent sponge was prepared into 0.005%, 0.01% and 0.02% (w/v) suspension, and 0.01%, 0.05% and 0.1% (v/v) extract groups. The control group was only the complete culture medium. Nothing was added to the blank group. In vitro cytotoxicity assay was used to evaluate the survival rate of cells. Eight patients underwent in vitro fertilization treatment in the Reproductive Center of Xiangya Hospital, Central South University from November 2019 to January 2020. The uterine fluid of each patient was aspirated. The experimental group was inhaled with sterile PVA formaldehyde absorbent sponge and then immersed RNA-later solution. The control group was directly injected into the same amount of RNA-later solution. RNA-seq and data analysis was performed later.

RESULTS

The vitro cytotoxicity assay showed that in suspension groups, there was no significance difference in cell survival between different co-culture time in 0.005% group (P=0.255). In the 0.01% and 0.02% group, there was no difference at each incubation time within 12 h (all P>0.05), but the cell survival rate was decreased at 24 h compared with 0 h (P<0.01, P<0.05). At the same co-culture time, the cell survival of the 3 concentration gradient groups were significantly lower than that of the control group (all P<0.05). The cell viability of the 0.005% concentration group was decreased less than 30% at 24 h, the 0.01% concentration group decreased more than 30% at 12 h, and the 0.02% concentration group was decreased more than 30% at 0 h. For extract groups, there was no significant difference in the survival rate within 6 h in 0.01% concentration group (all P>0.05), and the survival rate of 12 h and 24 h was lower than that of 0 h group (both P<0.01). In 0.05% group, there was no significant difference at each incubation time within 12 h (all P>0.05), but the survival rate at 24 h was lower than that at 0 h (P<0.05). There was no significant difference in survival rate at different culture time in 0.1% concentration group (P=0.082). At the same culture time, there was no significant difference in survival rate between 0.01% group and control group at 0, 3 and 24 h (all P>0.05). Except for 3 h, the survival rate of 0.05% and 0.1% groups was lower than that of control group (all P<0.05), and the decrease was all less than 30%. Uterine fluid RNA-seq showed that there was no significance difference in exonic rate, the detected genes and transcripts of RNA between the experiment groups and the control group (all P>0.05).

CONCLUSIONS

The in vitro cytotoxic of PVA formaldehyde absorbent sponge on human endometrial epithelial cell meet the national standard of the cytotoxic of medical materials. Sampling the uterine fluid with this material does not affect the RNA-Seq results. PVA formaldehyde absorbent sponge is safe and feasible when appling to the noninvasive uterine fluid sampling and RNA sequencing.

The role of timing in frozen embryo transfer

The process of implantation is characterized by a complex cross-talk between the endometrium and the blastocyst, with the endometrium only being receptive to implantation during a transient window of implantation of approximately 2-3 days during the midsecretory phase. The timing of embryo transfer, including frozen embryo transfer, is therefore critical to the success of implantation. In this article, we discuss various elements that may guide the timing of frozen embryo transfer, including the role of endometrial characteristics such as thickness, days postovulation or length of progesterone administration, stage of the embryo, and the application of endometrial receptivity tests to guide personalized embryo transfer.

Commercially Available Molecular Approaches to Evaluate Endometrial Receptivity: A Systematic Review and Critical Analysis of the Literature

Despite the advances in the field of reproductive medicine, implantation failure represents a challenging condition affecting 10-30% of patients subjected to in vitro fertilization (IVF). Research has focused on the identification of molecules playing crucial roles in endometrial receptivity, with the aim of designing predictive tools for efficient detection of the implantation window. To that end, novel molecular genomic and transcriptomic approaches have been introduced as promising tools to enable personalized approaches with the aim of optimizing embryo transfer dating. However, the clinical value of these approaches remains unclear. The aim of this study is to provide a systematic review and critical analysis of the existing evidence regarding the employment of commercially available novel approaches to evaluate endometrial receptivity. An Embase and PubMed/Medline search was performed on 1 February 2022. From the 475 articles yielded, only 27 were included and analyzed. The considerable heterogeneity of the included articles indicates the uniqueness of the implantation window, showcasing that the optimal time for embryo transfer varies significantly between women. Moreover, this study provides information regarding the technical aspects of these advanced molecular tools, as well as an analysis of novel possible biomarkers for endometrial receptivity, providing a basis for future research in the field.

Aging endometrium in young women: molecular classification of endometrial aging-based markers in women younger than 35 years with recurrent implantation failure

BACKGROUND

To explore the differences between a population with premature endometrial aging and a population with normal endometrial status in young women with recurrent implantation failure (< 35 years).

METHODS

Systematic analysis of the endometrium transcriptome of 274 RIF women. The NMF algorithm was used for classification based on endometrial-specific aging markers in CellAge, and the endometrial receptivity, gene expression patterns, and clinical data were compared between the classifications.

RESULTS

Two hundred forty-five young RIF women could be divided into two clusters, in which the aging gene expression pattern of cluster 2 was closer to the reference cluster. Cluster 1 was characterized by high immune activity, while cluster 2 was characterized by high metabolic activity. Combined with clinical data, cluster 2 was worse than cluster 1 in window of implantation deviation rate and endometrial receptivity.

CONCLUSION

Premature aging of the endometrium exists in young women with RIF, and premature aging of the endometrium was associated with poor reproductive outcomes.

The Clinical Efficacy of Personalized Embryo Transfer Guided by the Endometrial Receptivity Array/Analysis on IVF/ICSI Outcomes: A Systematic Review and Meta-Analysis

Objective: To assess the prevalence of displaced window of implantation (WOI) in infertile women, and the clinical utility of personalized embryo transfer (pET) guided by the endometrial receptivity array/analysis (ERA) on IVF/ICSI outcomes.

Methods: The protocol was registered at Prospero: CRD42020204237. We systematically searched all published English literature related to the prevalence of WOI displacement and ongoing pregnancy rate/live birth rate in the overall good-prognosis infertile patients (GPP) and/or repeated implantation failure (RIF) patients undergoing IVF/ICSI-ET cycles after ERA test until August 2021.

Result(s): 11 published studies were enrolled in the final analysis. The estimate of the incidence of WOI displacement based on ERA was 38% (95%CI 19–57%) in GPP and 34% (95%CI 24–43%) in RIF, respectively. There was no difference in OPR/LBR between patients undergoing routine ET without ERA test and those who following pET with ERA (39.5 vs. 53.7%, OR 1.28, p = 0.49, 95%CI 0.92–1.77, I² = 0%) in relative GPP. Notably, the meta-analysis revealed that OPR/LBR of patients with RIF undergoing pET who had non-receptive ERA increased to the level of to those undergoing sET with receptive ERA (40.7 vs.49.6%, OR 0.94, p = 0.85, 95%CI 0.70–1.26, I² = 0%).

Conclusion: Considering the approximately one third of infertile women could suffered from displaced WOI, the ERA test emerged as a promising tool. Although the present meta-analysis demonstrates that patients with general good-prognosis may not benefit from ERA, pET guided by ERA significantly increases the chances of pregnancy for non-receptive patients with RIF of endometrial origin.

The clinical efficiency of transcriptome-based endometrial receptivity assessment (Tb-ERA) in Chinese patients with recurrent implantation failure (RIF): A study protocol for a prospective randomized controlled trial

Background

Today, approximately 10% of participants in assisted reproductive technology (ART) are defined as having recurrent implantation failure (RIF). Recent studies show that endometrial receptivity array can improve pregnancy and implantation rates by nearly 20% in women with RIF. However, these studies are limited, with little published data in the Chinese population. Recently, we have established a transcriptome-based endometrial receptivity assessment (Tb-ERA) method of predicting the endometrial window of implantation (WOI) using transcriptome-profiling data of different phases of the menstrual cycle from healthy fertile Chinese women by RNA-Seq. It is meaningful to conduct a randomized controlled trial (RCT) to assess the clinical efficiency of Tb-ERA in Chinese patients with RIF.

Methods

In this RCT, a total of 200 RIF patients will be recruited and randomized into 2 groups. Patients in the Tb-ERA group will undergo a Tb-ERA test, after which embryo transfer time will be adjusted according to Tb-ERA results and embryo transfer will be performed again in the next cycle. Patients in the control group will not receive any interventions until the next transfer cycle. We will perform statistical analysis on both groups at the primary endpoint (clinical-pregnancy rate) and at secondary endpoints (rate of WOI displacement, embryo implantation, biochemical pregnancy, early abortion, and ectopic pregnancy). Implications: This study aims to evaluate the effectiveness of our Tb-ERA test in Chinese RIF patients and to determine that whether Tb-ERA could improve the clinical-pregnancy rate in these RIF patients.

Trial registration

NCT04497558, registered August 4, 2020.

Endometrial fluid aspiration immediately prior to embryo transfer does not affect IVF/vitrified-warmed embryo transfer outcomes - a prospective matched cohort study

RESEARCH QUESTION

Does the endometrial aspiration of ultrasound-invisible fluid immediately preceding embryo transfer affect IVF/vitrified-warmed embryo transfer outcomes?

DESIGN

A prospective matched cohort study was conducted in 96 women and 96 control participants to assess the effect on pregnancy outcomes of endometrial aspiration performed immediately before embryo transfer. This study was carried out at a university-affiliated assisted reproductive medical centre between January 2019 and December 2019. Patients were divided into two groups. The EA group had cycles with endometrial aspiration of ultrasound-invisible fluid performed before embryo transfer and the non-EA group featured cycles without endometrial aspiration. The EA group was matched by propensity score with the non-EA group in a 1:1 ratio. The EA group consisted of 99 participants before and 96 participants after propensity score matching. There were 203 and 96 participants in the non-EA group before and after propensity score matching.

RESULTS

No significant differences were detected in the baseline characteristics and cycle characteristics of the EA and non-EA groups. No significant between-group differences were found in reproductive outcomes in the overall population. Subgroup analysis of blastocyst transfer cycles showed the implantation rate was significantly higher in the EA group (61 women per group, 57.1% versus 40.8%, relative risk 1.40, 95% confidence interval 1.04-1.88; P = 0.022). Live birth rate, clinical pregnancy rate, ongoing pregnancy rate and multiple pregnancy rate were not different among the groups.

CONCLUSIONS

Endometrial aspiration immediately preceding embryo transfer does not affect IVF/vitrified-warmed embryo transfer outcomes. Interestingly, it might improve the vitrified-warmed blastocyst implantation rate. Randomized controlled trials are needed to confirm this result.

Integrated Analysis of Multiple Microarrays Based on Raw Data Identified Novel Gene Signatures in Recurrent Implantation Failure

BACKGROUND

Recurrent implantation failure (RIF) is an intricate complication following IVF-ET, which refers to the situation that good-quality embryos repeatedly fail to implant following two or more IVF cycles. Intrinsic molecular mechanisms underlying RIF have not yet been fully elucidated. With enormous improvement in high-throughput technologies, researchers screened biomarkers for RIF using microarray. However, the findings of published studies are inconsistent. An integrated study on the endometrial molecular determinants of implantation will help to improve pregnancy outcomes.

OBJECTIVE

To identify robust differentially expressed genes (DEGs) and hub genes in endometrium associated with RIF, and to investigate the diagnostic role of hub genes in RIF.

METHODS

Raw data from five GEO microarrays regarding RIF were analyzed. Integrated genetic expression analyses were performed using the Robust Rank Aggregation method to identify robust DEGs. Enrichment analysis and protein-protein interaction (PPI) analysis were further performed with the robust DEGs. Cytohubba was used to screen hub genes based on the PPI network. GSE111974 was used to validate the expression and diagnostic role of hub genes in RIF.

RESULTS

1532 Robust DEGs were identified by integrating four GEO datasets. Enrichment analysis showed that the robust DEGs were mainly enriched in processes associated with extracellular matrix remodeling, adhesion, coagulation, and immunity. A total of 18 hub genes (HMGCS1, SQLE, ESR1, LAMC1, HOXB4, PIP5K1B, GNG11, GPX3, PAX2, TF, ALDH6A1, IDH1, SALL1, EYA1, TAGLN, TPD52L1, ST6GALNAC1, NNMT) were identified. 10 of the 18 hub genes were significantly differentially expressed in RIF patients as validated by GSE111974. The 10 hub genes (SQLE, LAMC1, HOXB4, PIP5K1B, PAX2, ALDH6A1, SALL1, EYA1, TAGLN, ST6GALNAC1) were effective in predicting RIF with an accuracy rate of 85%, specificity rate of 100%, and sensitivity rate of 88.9%.

CONCLUSIONS

Our integrated analysis identified novel robust DEGs and hub genes in RIF. The hub genes were effective in predicting RIF and will contribute to the understanding of comprehensive molecular mechanisms in RIF pathogenesis.

The RNA-seq based endometrial receptivity test (rsERT) compared to pinopode: A better diagnostic tool for endometrial receptivity for patients with recurrent implantation failure in Chinese population

Displaced window of implantation (WOI) is one of the endometrial origins that accounts for implantation failure, especially for patients with recurrent implantation failure (RIF), yet no standard diagnostic tool has been recognized. The study consists of two parts, aiming to compare the concordance and efficacy of the diagnostic tools, the newly developed RNA-seq based endometrial receptivity test (rsERT) to the conventional pinopode, in diagnosing WOI and guiding personalized embryo transfer (pET). With the same group of RIF patients, the rsERT diagnosed 32 patients (65.31%) with normal WOIs, and most of the displacements were advancements (30.61%). While according to pinopode, only 14 patients (28.57%) were found with normal WOIs, and most patients (63.27%) presented delayed growth patterns. After conducting pET, patients in the rsERT group had higher successful pregnancy rates while requiring fewer ET cycles (50.00% vs. 16.67%, p=0.001). The study proved poor consistency between the diagnostic tools of endometrial receptivity based on cellular structure and gene profiling, and it supported rsERT as a reliable tool with potential clinical value.

Transcriptomic Analysis of STAT1/3 in the Goat Endometrium During Embryo Implantation

Interferon tau (IFNT), a pregnancy recognition signal in ruminants, promotes the establishment of embryo implantation by inducing the expression of interferon-stimulated genes (ISGs) via the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway. However, the precise regulatory mechanism of IFNT in goat embryo implantation remains largely unknown. In this study, we performed RNA sequencing of goat endometrial epithelial cells (gEECs) with or without 20 ng/mL IFNT treatment. Differential comparison showed that there were 442 upregulated differentially expressed genes (DEGs) and 510 downregulated DEGs. Bioinformatic analyses revealed that DEGs were significantly enriched in immune-related functions or pathways. The qRT-PCR validation results showed that the expression levels of STAT family members (STAT1, STAT2, and STAT3) were significantly upregulated in gEECs after IFNT treatment, which is in agreement with the RNA-seq data. Meanwhile, the protein levels of p-STAT1 and p-STAT3 increased significantly in gEECs after 6 and 24 h of IFNT treatment, respectively. Further in vivo experiments also confirmed that both mRNA and protein phosphorylation levels of STAT1 and STAT3 in the uterus on day 18 of pregnancy (P18) were significantly increased compared to those on day 5 (P5) and day 15 of pregnancy (P15). On P5, STAT1 and STAT3 proteins were primarily located in the uterine luminal epithelium (LE) and glandular epithelium (GE), and were also detected in the stromal cells. The intense immunostaining of STAT1 and STAT3 proteins were decreased on P15 and then increased on P18, especially in the superficial GE and subepithelial stromal cells. Moreover, p-STAT1 and p-STAT3 were highly expressed in the deep GE on P18. Collectively, these results highlight the role of IFNT in regulating endometrial receptivity in gEECs and uncover the temporal and spatial changes in the expression of STAT1/3 during embryo implantation in the goat endometrium.

Factors Affecting Artificial Insemination Pregnancy Outcome

Objective

The aim of the present study was to explore related clinical pregnancy outcome factors in intrauterine insemination (IUI).

Materials and Methods

The clinical data of 3984 IUI cycles in 1862 couples experiencing infertility who attended the Reproductive Center of Binzhou Medical University Hospital between July 2006 and July 2017 were retrospectively analyzed. Female and male patient age, endometrial thickness (EMT), the post-wash total motile sperm count (PTMC), artificial insemination timing, insemination frequency, and ovarian stimulation protocols were compared between the study’s pregnant group and non-pregnant group in order to explore any correlation.

Results

There were statistically significant differences in female and male age, EMT, artificial insemination timing, insemination frequency, and ovarian stimulation protocols between the two groups (p < 0.05). The clinical pregnancy rate was significantly higher in ovarian stimulation cycles than in natural cycles (21.2% and 11.6%, respectively; p < 0.01), the clinical pregnancy rate was significantly higher in double IUI than in single IUI (17.8% and 12.1%, respectively; p < 0.01), and EMT was significantly greater in the pregnant group than in the control group (p < 0.05). However, the differences in clinical pregnancy rates among the PTMC groups were not statistically significant (14.8%, 14.4%, 17.3%, and 17.3%, respectively; p > 0.05).

Conclusion

The results of the present study demonstrate that the clinical IUI pregnancy rate is correlated with the factors of female age, male age, EMT, artificial insemination timing, insemination frequency, and ovarian stimulation protocols; the ovarian stimulation protocol can noticeably improve the patient pregnancy outcome. Furthermore, compared with single IUI, double IUI can significantly increase the clinical pregnancy rate.