Endometrial transcriptome profiling of patients with recurrent implantation failure during hormone replacement therapy cycles.

Background: The molecular mechanisms underlying window of implantation (WOI) displacement in patients with recurrent implantation failure (RIF) remain unclear. This study aims to explore the transcriptomic signatures of endometrium with normal and displaced WOIs and to identify the causes of endometrial receptivity (ER) abnormalities and WOI displacement in RIF patients. Methods: In this study, 40 RIF patients were recruited and underwent personalized embryo transfer (pET) guided by the predicted results of endometrial receptivity diagnosis (ERD) model. Transcriptome analysis of endometrium from patients with clinical pregnancies after pET was performed to identify differentially expressed genes (DEGs) associated with WOI displacement. Gene expression data from HRT and natural cycle endometrium were compared to identify specific gene expression patterns of ER-related genes during WOI. Results: The ERD results indicated that 67.5% of RIF patients (27/40) were non-receptive in the conventional WOI (P+5) of the HRT cycle. The clinical pregnancy rate in RIF patients improved to 65% (26/40) after ERD-guided pET, indicating the effectiveness of transcriptome-based WOI prediction. Among the 26 patients with clinical pregnancy, the gene expression profiles of P+5 endometrium from advanced (n=6), normal (n=10) and delayed (n=10) WOI groups were significantly different from each other. Furthermore, 10 DEGs identified among P+5 endometrium of 3 groups were involved in immunomodulation, transmembrane transport and tissue regeneration, which could accurately classify the endometrium with different WOIs. Additionally, a large number of ER-related genes showed significant correlation and similar gene expression patterns in P+3, P+5, and P+7 endometrium from HRT cycles and LH+5, LH+7, and LH+9 endometrium from natural cycles. Conclusion: Our study shows that ER-related genes share similar gene expression patterns during WOI in both natural and HRT cycles, and their aberrant expression is associated with WOI displacements. The improvement of pregnancy outcomes in RIF patients by adjusting ET timing according to ERD results demonstrates the importance of transcriptome-based endometrial receptivity assessment and the clinical efficiency of ERD model.

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.

Transcriptomic analysis of endometrial receptivity for a genomic diagnostics model of Chinese women.

OBJECTIVE: To define the transcriptomic signature with respect to human endometrial receptivity in Chinese women by next-generation sequencing and to develop a more refined and customized bioinformatic predictive method for endometrial dating in Chinese women. DESIGN: Randomized. SETTING: A tertiary hospital-based reproductive medicine center. PATIENT(S): Ninety healthy, fertile Chinese women. INTERVENTION(S): Human endometrial biopsies. MAIN OUTCOME MEASURE(S): Gene expression of endometrial biopsies. RESULT(S): Ninety endometrial samples from healthy Chinese women during their menstrual cycles-including prereceptive (luteinizing hormone [LH] + 3 days/LH + 5 days), receptive (LH + 7 days), and post-receptive (LH + 9 days) phases-were subjected to transcriptomic analysis using messenger RNA (mRNA)-enriched RNA-Seq. Feature genes were obtained and used to train the predictor for endometrial dating, with 63 samples for the training set and 27 samples for the validation set. Differentially expressed genes (DEGs) were identified by comparing samples from different phases of the menstrual cycle. Based on the transcriptomic feature genes, we constructed a bioinformatic predictor for endometrial dating. The accuracy on assessment of the endometrium on days LH + 3, LH + 5, LH + 7, and LH + 9 was 100% in the training set and 85.19% in the validation set. CONCLUSION(S): Our transcriptomic profiling method can be used to monitor the window of implantation with regard to the endometrium in the Chinese population. This method potentially provides an evaluation of endometrial status, and can be used to predict a personal window of implantation by reproductive medicine clinicians.

Non-invasive metabolomic profiling of embryo culture media and morphology grading to predict implantation outcome in frozen-thawed embryo transfer cycles.

PURPOSE: Assessment of embryo viability is a crucial component of in vitro fertilization and currently relies largely on embryo morphology and cleavage rate. Because morphological assessment remains highly subjective, it can be unreliable in predicting embryo viability. This study investigated the metabolomic profiling of embryo culture media using near-infrared (NIR) spectroscopy for predicting the implantation potential of human embryos in frozen-thawed embryo transfer (FET) cycles. METHODS: Spent embryo culture media was collected on day 4 after thawed embryo transfer (n = 621) and analysed using NIR spectroscopy. Viability scores were calculated using a predictive multivariate algorithm of fresh embryos with known pregnancy outcomes. RESULTS: The mean viability indices of embryos resulting in clinical pregnancy following FET were significantly higher than those of non-implanted embryos and differed between the 0, 50, and 100 % implantation groups. Notably, the 0 % group index was significantly lower than the 100 % implantation group index (-0.787 ± 0.382 vs. 1.064 ± 0.331, P < 0.01). To predict implantation outcomes, we examined the area under the ROC curve (AUCROC), which was significantly higher for the viability than for the morphology score (0.94 vs. 0.55; P < 0.01); however, the AUCROCs for the composite and viability scores did not differ significantly (0.92 vs. 0.94; P > 0.05). CONCLUSIONS: NIR metabolomic profiling of thawed embryo culture media is independent of morphology and correlates with embryo implantation potential in FET cycles. The viability score alone or in conjunction with morphologic grading is a more objective marker for implantation outcome in FET cycles than morphology alone.

A study in vitro on differentiation of bone marrow mesenchymal stem cells into endometrial epithelial cells in mice.

OBJECTIVE: To investigate the differentiation conditions of bone marrow mesenchymal stem cells (BMSCs) into endometrial epithelial cells and to confirm the effect of 17ß-estradiol in this process. STUDY DESIGN: BMSCs were cultured alone or co-cultured with endometrial stromal cells (EStCs) in control/differentiation medium (17ß-estradiol, growth factors) and were co-cultured with EStCs in different concentrations of 17ß-estradiol. Flow cytometry and immunocytochemistry were used to identify the isolated cells. Real-time RT-PCR and immunofluorescence were used to test the expression of epithelial cell markers. RESULTS: The epithelial markers cytokeratin-7, cytokeratin-18, cytokeratin-19, and epithelial membrane antigen were elevated in real-time RT-PCR (P<0.05), and cytokeratin was strongly positive in immunofluorescence analysis in the differentiated BMSCs. Cytokeratin-7 and cytokeratin-19 expression levels were highest in the 1 × 10⁻8 mol/L 17ß-estradiol group, as shown in real-time RT-PCR (P<0.05). CONCLUSION: BMSCs could be differentiated in the direction of endometrial epithelial cells in appropriate conditions in vitro: 17ß-estradiol may play a key role in stimulating BMSCs' epithelial differentiation in the process of endometriosis. CONDENSATION: Bone marrow mesenchymal stem cells can differentiate in the direction of endometrial epithelial cells in a certain microenvironment and appropriate concentration of 17ß-E2 can facilitate this differentiation.