Predicting risk of endometrial failure: a biomarker signature that identifies a novel disruption independent of endometrial timing in patients undergoing hormonal replacement cycles.

OBJECTIVE: To propose a new gene expression signature that identifies endometrial disruptions independent of endometrial luteal phase timing and predicts if patients are at risk of endometrial failure. DESIGN: Multicentric, prospective study. SETTING: Reproductive medicine research department in a public hospital affiliated with private fertility clinics and a reproductive genetics laboratory. PATIENTS: Caucasian women (n = 281; 39.4 ± 4.8 years old with a body mass index of 22.9 ± 3.5 kg/m2) undergoing hormone replacement therapy between July 2018 and July 2021. Endometrial samples from 217 patients met RNA quality criteria for signature discovery and analysis. INTERVENTION(S): Endometrial biopsies collected in the mid-secretory phase. MAIN OUTCOME MEASURE(S): Endometrial luteal phase timing-corrected expression of 404 genes and reproductive outcomes of the first single embryo transfer (SET) after biopsy collection to identify prognostic biomarkers of endometrial failure. RESULTS: Removal of endometrial timing variation from gene expression data allowed patients to be stratified into poor (n = 137) or good (n = 49) endometrial prognosis groups on the basis of their clinical and transcriptomic profiles. Significant differences were found between endometrial prognosis groups in terms of reproductive rates: pregnancy (44.6% vs. 79.6%), live birth (25.6% vs. 77.6%), clinical miscarriage (22.2% vs. 2.6%), and biochemical miscarriage (20.4% vs. 0%). The relative risk of endometrial failure for patients predicted as a poor endometrial prognosis was 3.3 times higher than those with a good prognosis. The differences in gene expression between both profiles were proposed as a biomarker, coined the endometrial failure risk (EFR) signature. Poor prognosis profiles were characterized by 59 upregulated and 63 downregulated genes mainly involved in regulation (17.0%), metabolism (8.4%), immune response, and inflammation (7.8%). This EFR signature had a median accuracy of 0.92 (min = 0.88, max = 0.94), median sensitivity of 0.96 (min = 0.91, max = 0.98), and median specificity of 0.84 (min = 0.77, max = 0.88), positioning itself as a promising biomarker for endometrial evaluation. CONCLUSION(S): The EFR signature revealed a novel endometrial disruption, independent of endometrial luteal phase timing, present in 73.7% of patients. This EFR signature stratified patients into 2 significantly distinct and clinically relevant prognosis profiles providing opportunities for personalized therapy. Nevertheless, further validations are needed before implementing this gene signature as an artificial intelligence (AI)-based tool to reduce the risk of patients experiencing endometrial failure.

Deciphering a shared transcriptomic regulation and the relative contribution of each regulator type through endometrial gene expression signatures.

BACKGORUND: While various endometrial biomarkers have been characterized at the transcriptomic and functional level, there is generally a poor overlap among studies, making it unclear to what extent their upstream regulators (e.g., ovarian hormones, transcription factors (TFs) and microRNAs (miRNAs)) realistically contribute to menstrual cycle progression and function. Unmasking the intricacies of the molecular interactions in the endometrium from a novel systemic point of view will help gain a more accurate perspective of endometrial regulation and a better explanation the molecular etiology of endometrial-factor infertility. METHODS: An in-silico analysis was carried out to identify which regulators consistently target the gene biomarkers proposed in studies related to endometrial progression and implantation failure (19 gene lists/signatures were included). The roles of these regulators, and of genes related to progesterone and estrogens, were then analysed in transcriptomic datasets compiled from samples collected throughout the menstrual cycle (n = 129), and the expression of selected TFs were prospectively validated in an independent cohort of healthy participants (n = 19). RESULTS: A total of 3,608 distinct genes from the 19 gene lists were associated with endometrial progression and implantation failure. The lists' regulation was significantly favoured by TFs (89% (17/19) of gene lists) and progesterone (47% (8 /19) of gene lists), rather than miRNAs (5% (1/19) of gene lists) or estrogen (0% (0/19) of gene lists), respectively (FDR < 0.05). Exceptionally, two gene lists that were previously associated with implantation failure and unexplained infertility were less hormone-dependent, but primarily regulated by estrogen. Although endometrial progression genes were mainly targeted by hormones rather than non-hormonal contributors (odds ratio = 91.94, FDR < 0.05), we identified 311 TFs and 595 miRNAs not previously associated with ovarian hormones. We highlight CTCF, GATA6, hsa-miR-15a-5p, hsa-miR-218-5p, hsa-miR-107, hsa-miR-103a-3p, and hsa-miR-128-3p, as overlapping novel master regulators of endometrial function. The gene expression changes of selected regulators throughout the menstrual cycle (FDR < 0.05), dually validated in-silico and through endometrial biopsies, corroborated their potential regulatory roles in the endometrium. CONCLUSIONS: This study revealed novel hormonal and non-hormonal regulators and their relative contributions to endometrial progression and pathology, providing new leads for the potential causes of endometrial-factor infertility.

Association of blood cadmium and lead levels with self-reported reproductive lifespan and pregnancy loss: The national health and nutrition examination survey 1999-2018.

Cadmium and lead are known to interfere with the endocrine function. Thus, hormonally regulated processes such as menarche, menopause and pregnancy are likely influenced by chronic exposure to these metals. In US post-menopausal women, who already completed their reproductive lifespan, we evaluated the association between blood cadmium and lead levels with self-reported reproductive lifespan and personal history of pregnancy loss. We selected 5317 post-menopausal women participating in the National Health and Nutrition Examination Survey (NHANES), 1999-2018. Blood cadmium and lead levels were measured by inductively coupled plasma mass spectrometry. Reproductive lifespan was defined as the number of years between self-reported age at menarche and menopause. Personal history of pregnancy loss was defined as number of self-reported pregnancy losses out of the self-reported number of pregnancies. The fully adjusted mean difference in reproductive lifespan (95% confidence interval [CI]) comparing the 80th to the 20th percentiles of blood cadmium and lead distributions was, respectively, 0.50 (0.10, 0.91) and 0.72 (0.41, 1.03) years. Ever smoker showed stronger association of blood lead with reproductive lifespan. For self-reported pregnancy loss, the corresponding fully adjusted relative prevalence (95% CI) was 1.10 (0.93, 1.31) for cadmium and 1.10 (1.00, 1.21) for lead, and remained similar after additional adjustment for reproductive lifespan. In never smokers, the relative prevalence was 1.07 (1.04, 1.11) and 1.16 (1.05, 1.28) for blood cadmium and lead, respectively. These findings suggest that blood cadmium and lead exposures increase reproductive lifespan and prevalence of pregnancy loss in the general population. Additional studies are needed to improve the understanding of mechanisms and prevention potential of metals-related pregnancy outcomes.

Endometrial gene expression differences in women with coronavirus disease 2019.

OBJECTIVE: To study the potential effect of coronavirus disease (COVID-19) on the endometrial transcriptome of affected, symptomatic women for the detection of altered gene expression. DESIGN: Pilot study of the endometrial transcriptomes of women manifesting COVID-19 compared with those of women without COVID-19 undergoing hysteroscopic procedures for benign gynecologic disorders using RNA sequencing. SETTING: Hospital and university laboratories. PATIENT(S): Women with (n = 14) and without a COVID-19 (n = 10) diagnosis based on a nasopharyngeal swab analysis using quantitative reverse-transcription polymerase chain reaction. The endometrium of the patients with COVID-19 had previously been tested for severe acute respiratory syndrome coronavirus 2 infection, revealing the absence of the virus in this tissue. INTERVENTION(S): Endometrial biopsy sample collection. MAIN OUTCOMES MEASURE(S): Endometrial gene expression and functional analysis of symptomatic patients with COVID-19 vs. individuals without the infection. RESULT(S): The systemic disease COVID-19 altered endometrial gene expression in 75% of the women, with the patients exhibiting a preponderance of 163 up-regulated (e.g., UTS2, IFI6, IFIH1, and BNIP3) and 72 down-regulated genes (e.g., CPZ, CDH3, and IRF4) (false discovery rate<0.05). A total of 161 dysregulated functions (36 up-regulated and 125 down-regulated) were typically enriched in the endometria of the patients with COVID-19, including up-regulation in pathways involved in the development of immune responses to viruses and cytokine inflammation, reflecting elicitation of a COVID-19 response pathway. CONCLUSION(S): Coronavirus disease 2019 affects endometrial gene expression despite the absence of severe acute respiratory syndrome coronavirus 2 RNA in endometrial tissues.

Pathways and factors regulated by bone marrow-derived stem cells in human ovarian tissue.

OBJECTIVE: To describe molecular and paracrine signaling changes produced by human bone marrow-derived stem cells (BMDSC) in human ovarian cortex. DESIGN: Experimental study. SETTING: University hospital research laboratories. PATIENT(S): Ovarian cortex from poor responder women (n = 7). ANIMALS: Immunodeficient NOD/SCID female mice (n = 18). INTERVENTION(S): Human ovarian cortex strips were xenografted into ovariectomized NOD/SCID female mice. A week later, mice were infused with phosphate-buffered saline, 1 × 106 BMDSC, or 3 × 105 CD133+ cells via tail vein. Gene expression changes and enriched pathways were assessed by RT2 Profiler Arrays. Several upregulated genes were validated in individual samples by real-time quantitative PCR, and transcriptomic results were reinforced by a proteomic assessment. MAIN OUTCOME MEASURE(S): Gene expression changes, enriched Kyoto Encyclopedia of Genes and Genomes pathways, and paracrine factors. RESULT(S): Seventy-four Kyoto Encyclopedia of Genes and Genomes pathways were upregulated, with the PI3K-Akt signaling pathway the most enriched after BMDSC and CD133 treatments. The greatest transcriptomic changes were seen on day 14 in the BMDSC group, affecting the regulation of paracrine factors such as KITLG, THBS1, SERPINF1, and TIMP2. Proteomics data verified changes in FoxO signaling, actin cytoskeleton remodeling, and apoptosis by BMDSC. CONCLUSION(S): We identified paracrine factors and pathways regulated by BMDSC that may be future targets of treatment for the increasing number of poor responder women. Our findings suggest that BMDSC upregulated soluble factors such as KITLG, THBS1, SERPINF1, and TIMP2 as well as PI3K-Akt signaling and regulation of actin cytoskeleton pathways. The identification of these putative underlying mechanisms informs future experiments aiming to optimizing clinical application of BMDSC.

Guidelines for biomarker discovery in endometrium: correcting for menstrual cycle bias reveals new genes associated with uterine disorders.

Transcriptomic approaches are increasingly used in reproductive medicine to identify candidate endometrial biomarkers. However, it is known that endometrial progression in the molecular biology of the menstrual cycle is a main factor that could affect the discovery of disorder-related genes. Therefore, the aim of this study was to systematically review current practices for considering the menstrual cycle effect and to demonstrate its bias in the identification of potential biomarkers. From the 35 studies meeting the criteria, 31.43% did not register the menstrual cycle phase. We analysed the menstrual cycle effect in 11 papers (including 12 studies) from Gene Expression Omnibus: three evaluating endometriosis, two evaluating recurrent implantation failure, one evaluating recurrent pregnancy loss, one evaluating uterine fibroids and five control studies, which collected endometrial samples throughout menstrual cycle. An average of 44.2% more genes were identified after removing menstrual cycle bias using linear models. This effect was observed even if studies were balanced in the proportion of samples collected at different endometrial stages or only in the mid-secretory phase. Our bias correction method increased the statistical power by retrieving more candidate genes than per-phase independent analyses. Thanks to this practice, we discovered 544 novel candidate genes for eutopic endometriosis, 158 genes for ectopic ovarian endometriosis and 27 genes for recurrent implantation failure. In conclusion, we demonstrate that menstrual cycle progression masks molecular biomarkers, provides new guidelines to unmask them and proposes a new classification that distinguishes between biomarkers of disorder or/and menstrual cycle progression.

Evaluation of the endometrial receptivity assay and the preimplantation genetic test for aneuploidy in overcoming recurrent implantation failure.

PURPOSE: To evaluate the clinical usefulness of the endometrial receptivity array (ERA) and the preimplantation genetic test for aneuploidy (PGT-A) in patients with severe and moderate recurrent implantation failure (RIF). DESIGN: A retrospective multicenter cohort study was conducted in patients who failed to achieve implantation following transfer of 3 or more or 5 or more embryos in at least three single embryo transfers; patients were classified as moderate or severe RIF, respectively. Patients with previous RIF were compared based on the testing they received: PGT-A, ERA, or PGT-A+ERA versus a control group with no testing. Mean implantation rate and ongoing pregnancy rates per embryo transfer were considered primary outcomes. Multiple logistic regression analysis was performed and adjusted ORs were calculated to control possible bias. RESULTS: Of the 2110 patients belonging to the moderate RIF group, those who underwent transfer of euploid embryos after PGT-A had a higher implantation rate than those who did not. Additionally, the PGT-A group had a significantly higher rate of ongoing pregnancy. The same outcomes measured for the 488 patients in the severe RIF group did not reveal any statistically significant improvements. The use of the ERA test did not appear to significantly improve outcomes in either group. CONCLUSIONS: PGT-A may be beneficial for patients with moderate recurrent implantation failure but not for severe cases. At its current level of development, ERA does not appear to be clinically useful for patients with RIF.

SARS-CoV-2 infection risk assessment in the endometrium: viral infection-related gene expression across the menstrual cycle.

OBJECTIVE: To determine the susceptibility of the endometrium to infection by-and thereby potential damage from-SARS-CoV-2. DESIGN: Analysis of SARS-Cov-2 infection-related gene expression from endometrial transcriptomic data sets. SETTING: Infertility research department affiliated with a public hospital. PATIENT(S): Gene expression data from five studies in 112 patients with normal endometrium collected throughout the menstrual cycle. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Gene expression and correlation between viral infectivity genes and age throughout the menstrual cycle. RESULT(S): Gene expression was high for TMPRSS4, CTSL, CTSB, FURIN, MX1, and BSG; medium for TMPRSS2; and low for ACE2. ACE2, TMPRSS4, CTSB, CTSL, and MX1 expression increased toward the window of implantation. TMPRSS4 expression was positively correlated with ACE2, CTSB, CTSL, MX1, and FURIN during several cycle phases; TMPRSS2 was not statistically significantly altered across the cycle. ACE2, TMPRSS4, CTSB, CTSL, BSG, and MX1 expression increased with age, especially in early phases of the cycle. CONCLUSION(S): Endometrial tissue is likely safe from SARS-CoV-2 cell entry based on ACE2 and TMPRSS2 expression, but susceptibility increases with age. Further, TMPRSS4, along with BSG-mediated viral entry into cells, could imply a susceptible environment for SARS-CoV-2 entry via different mechanisms. Additional studies are warranted to determine the true risk of endometrial infection by SARS-CoV-2 and implications for fertility treatments.

Uterine disorders affecting female fertility: what are the molecular functions altered in endometrium?

OBJECTIVE: To determine the molecular functions of genes exhibiting altered expression in the endometrium of women with uterine disorders affecting fertility. DESIGN: Retrospective analysis integrating case and control data from multiple cohorts with endometrium gene expression in women with uterine disorders. SETTING: Infertility research department affiliated with a university hospital. PATIENT(S): Two hundred and forty women, 121 of whom were controls, 119 of whom had endometrial adenocarcinoma (ADC), recurrent implantation failure (RIF), recurrent pregnancy loss (RPL), or stage II-IV endometriosis. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Genomewide gene expression and altered molecular functions in the endometrium of each uterine disorder. RESULT(S): Using robust analysis methods, we identified statistically significantly altered endometrial functions in all the uterine disorders. Cell cycle alterations were shared among all the pathologies investigated. Endometriosis was characterized by the down-regulation of ciliary processes. Among the endometriosis, ADC, and RIF samples, mitochondrial dysfunction and protein degradation were shared dysregulated processes. In addition, RPL had the most distinct functional profile, and 95% of affected functions were down-regulated. CONCLUSION(S): The most robust functions dysregulated in the endometrium of patients with uterine disorders across sample cohorts implicated an endometrial factor at the gene expression level. This shared endometrial factor affects endometrial receptivity processes.

iTRAQ comparison of proteomic profiles of endometrial receptivity.

Endometrial receptivity is a limiting step in human reproduction. A disruption in the development of endometrial receptivity is responsible for recurrent implantation failures (RIF) of endometrial origin. To understand the molecular mechanisms behind the endometrial receptivity process, we used the isobaric tag for relative and absolute quantitation (iTRAQ) method to compare three different endometrial statuses: fertile women, intrauterine device (IUD) carriers, and RIF patients. Overall, iTRAQ allowed identified 1889 non-redundant proteins. Of these, 188 were differentially expressed proteins (DEP) (p-value < .05). Pairwise comparisons revealed 133 significant DEP in fertile vs. IUD carriers and 158 DEP in RIF vs. IUD carriers. However, no DEP were identified between fertile and RIF patients. Western blot validation of three DEP involved in endometrial receptivity (plastin 2, lactotransferrin, and lysozyme) confirmed our iTRAQ results. Moreover, functional KEGG enrichment revealed that complement and coagulation cascades and peroxisome were the two most significant pathways for the RIF vs. IUD comparison and ribosome and spliceosome for the fertile vs. IUD comparison, as possible important pathways involved in the endometrial receptivity acquisition. The lack of DEP between fertile and RIF patient endometria suggest that idiopathic RIF may not have an endometrial origin, with other as-yet-unknown factors involved. SIGNIFICANCE: A pilot study where a comparison of the endometrial protein profile from women with different endometrial receptive grade (fertile women, IUD carriers and RIF patients) during the same period of time (overlapping with the window of implantation) of a hormone replacement therapy was performed using a high-throughput proteomic technique. This approach lead us to better understand the molecular mechanisms undergoing endometrial receptivity, a time-limiting step to achieve pregnancy in humans. Moreover, the number of samples per group (10 Fertile women, 10 IUD carriers and 8 RIF patients) according to the methodology here employed (8plex iTRAQ), give more robustness to our results. Our findings confirm that an IUD introduces numerous changes in the endometrial protein profile when compared to fertile and RIF endometria, revealing some key proteins involved in endometrial receptivity. Finding no significant differences between Fertile and RIF patient endometria could suggest that other as-yet-unknown factors could be involved in the etiology of idiopathic RIF.

Window of implantation transcriptomic stratification reveals different endometrial subsignatures associated with live birth and biochemical pregnancy.

OBJECTIVE: To refine the endometrial window of implantation (WOI) transcriptomic signature by defining new subsignatures associated to live birth and biochemical pregnancy. DESIGN: Retrospective cohort study. SETTING: University-affiliated in vitro fertilization clinic and reproductive genetics laboratory. PATIENT(S): Healthy fertile oocyte donors (n = 79) and patients with infertility diagnosed by Endometrial Receptivity Analysis (n = 771). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): WOI transcriptomic signatures associated with specific reproductive outcomes. RESULT(S): The retrospective cohort study was designed to perform a prediction model based on transcriptomic clusters for endometrial classification (training set, n = 529). The clinical follow-up set in the expected WOI (n = 321) was tested with the transcriptomic predictor to detect WOI variability and the pregnancy outcomes associated with these subsignatures (n = 228). The endometrial receptivity signature was redefined into four WOI transcriptomic profiles. This stratification identified an optimal endometrial receptivity (RR) signature resulting in an ongoing pregnancy rate (OPR) of 80% in terms of live birth, as well as a late receptive-stage (LR) signature with a potential high risk of 50% biochemical pregnancy. Abnormal down-regulation of the cell cycle was the main dysregulated function among the 22 genes associated with biochemical pregnancy. CONCLUSION(S): The major differences between the WOI transcriptomic stratification were in the OPR and biochemical pregnancy rate. The OPR ranged from 76.9% and 80% in the late prereceptive (LPR) and RR signatures, respectively, versus 33.3% in the LR. The biochemical pregnancy rate was 7.7% and 6.6% in LPR and RR, respectively, but 50% in LR, which highlights the relevance of endometrial status in the progression of embryonic implantation.

Defective decidualization during and after severe preeclampsia reveals a possible maternal contribution to the etiology.

In preeclampsia (PE), cytotrophoblast (CTB) invasion of the uterus and spiral arteries is often shallow. Thus, the placenta's role has been a focus. In this study, we tested the hypothesis that decidual defects are an important determinant of the placental phenotype. We isolated human endometrial stromal cells from nonpregnant donors with a previous pregnancy that was complicated by severe PE (sPE). Compared with control cells, they failed to decidualize in vitro as demonstrated by morphological criteria and the analysis of stage-specific antigens (i.e., IGFBP1, PRL). These results were bolstered by global transcriptional profiling data that showed they were transcriptionally inert. Additionally, we used laser microdissection to isolate the decidua from tissue sections of the maternal-fetal interface in sPE. Global transcriptional profiling revealed defects in gene expression. Also, decidual cells from patients with sPE, which dedifferentiated in vitro, failed to redecidualize in culture. Conditioned medium from these cells failed to support CTB invasion. To mimic aspects of the uterine environment in normal pregnancy, we added PRL and IGFBP1, which enhanced invasion. These data suggested that failed decidualization is an important contributor to down-regulated CTB invasion in sPE. Future studies will be aimed at determining whether this discovery has translational potential with regard to assessing a woman's risk of developing this pregnancy complication.

Lipidomic profiling of endometrial fluid in women with ovarian endometriosis†.

The proteomic content of the endometrial fluid (EF) from patients with endometriosis has been investigated, but the lipidomic profile has not been analyzed yet in detail.This study is a comparative untargeted lipidomic analysis of human EF obtained from 35 patients (12 endometriosis and 23 controls). Global differential lipidomic profile was analyzed in both groups by ultrahigh performance liquid chromatography coupled to mass spectrometry. A total of 123 out of the 457 metabolites identified in the EF were found to be significantly differentially expressed between ovarian endometriosis (OE) versus controls. Univariate statistical analysis showed reduced levels of saturated diacylglycerols and saturated triacylglycerols in endometriosis patients. A predictive model was generated using the 123 differentially expressed metabolites. Using this model, we were able to correctly classify 86% of the samples. This study identified the lipidomic profile in the EF associated with OE, suggesting that EF analysis could be considered as a minimally invasive approach for the diagnosis of endometriosis. In conclusion, the lipidomic profile of the EF is different between samples from patients with OE and controls.

Does an increased body mass index affect endometrial gene expression patterns in infertile patients? A functional genomics analysis.

OBJECTIVE: To analyze the transcriptomic profile of endometrial gene alterations during the window of implantation in infertile obese patients. DESIGN: Multicenter, prospective, case-control study. SETTING: Three academic medical centers for reproductive medicine. PATIENT(S): Infertile patients, stratified into body mass index (BMI) categories according to the World Health Organization guidelines, were included in the study. INTERVENTION(S): Endometrial samples were obtained from women undergoing standardized estrogen and P replacement cycles after 5 days of vaginal P supplementation. MAIN OUTCOME MEASURE(S): To identify endometrial gene expression alterations that occur during the window of implantation in infertile obese patients as compared with infertile normal-weight controls using a microarray analysis. RESULT(S): XCL1, XCL2, HMHA1, S100A1, KLRC1, COTL1, COL16A1, KRT7, and MFAP5 are significantly dysregulated during the window of implantation in the receptive endometrium of obese patients. COL16A1, COTL1, HMHA1, KRCL1, XCL1, and XCL2 were down-regulated and KRT7, MFAP5, and S100A1 were up-regulated in the endometrium of obese patients. These genes are mainly involved in chemokine, cytokine, and immune system activity and in the structural extracellular matrix and protein-binding molecular functions. CONCLUSION(S): Obesity is associated with significant endometrial transcriptomic differences as compared with non-obese subjects. Altered endometrial gene expression in obese patients may contribute to the lower implantation rates and increased miscarriage rates seen in obese infertile patients. CLINICAL TRIAL REGISTRATION NUMBER: NCT02205866.

Leucine-rich repeat-containing G-protein-coupled receptor 5-positive cells in the endometrial stem cell niche.

OBJECTIVE: To study, isolate and characterize leucine-rich repeat-containing heterotrimeric guanine nucleotide-binding protein-coupled receptor 5 (LGR5)-positive cells from human endometrium to determine their functional relevance. DESIGN: Prospective experimental animal study. SETTING: University research laboratories. ANIMAL(S): Nonobese diabetic mice (NOD-SCID) (strain code 394; NOD.CB17-Prkdcscid/NcrCrl). INTERVENTION(S): Human LGR5+ cells were labeled with superparamagnetic iron oxide nanoparticles (SPIOs) and injected under the kidney capsule in immunocompromised mice. MAIN OUTCOME MEASURE(S): Epithelial and stromal LGR5+ cells were isolated from human endometrium by means of fluorescence-activated cell sorting, and phenotypic characterization was performed by means of flow cytometry with the use of hematopoietic and mesenchymal markers. Engrafted SPIO-labeled LGR5+ cells were localized with the use of Prussian blue staining and immunohistochemistry against CD9 and Vimentin. Deep transcriptomic profiling of LGR5+ cells was performed with the use of microarrays and RNA sequencing. RESULT(S): The percentage of LGR5+ cells in human endometrium represented 1.08 ± 0.73% and 0.82 ± 0.76% of total cells in the epithelial and stromal compartments, respectively. LGR5+ cells were phenotypically characterized by abundant expression of CD45 hematopoietic marker and no expression of surface markers CD31, CD34, CD133, CD73, and CD90. Coexpression with the macrophage marker CD163 was detected. Xenotransplantation of labeled LGR5+ cells into the kidney capsules of immunocompromised mice resulted in a weak endometrial reconstitution from this cell of origin. Transcriptomic profiling revealed new attributes for LGR5+ cells related to their putative hematopoietic origin. CONCLUSION(S): These data suggest that endometrial LGR5 is not an endogenous stem cell marker. Instead, LGR5+ cells appear to be recruited from blood to be part of the stem cell niche at the perivascular microenvironment to activate the endogenous niche.

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

STUDY QUESTION: Does a single intrauterine infusion of human chorionic gonadotropin (hCG) at the time corresponding to a Day 3 embryo transfer in oocyte donors induce favorable molecular changes in the endometrium for embryo implantation? SUMMARY ANSWER: Intrauterine hCG was associated with endometrial synchronization between endometrial glands and stroma following ovarian stimulation and the induction of early decidual markers associated with stromal cell survival. WHAT IS KNOWN ALREADY: The clinical potential for increasing IVF success rates using an intrauterine hCG infusion prior to embryo transfer remains unclear based on previously reported positive and non-significant findings. However, infusion of CG in the non-human primate increases the expression of pro-survival early decidual markers important for endometrial receptivity, including α-smooth muscle actin (α-SMA) and NOTCH1. STUDY DESIGN, SIZE, DURATION: Oocyte donors (n=15) were randomly assigned to receive an intrauterine infusion of 500 IU hCG (n=7) or embryo culture media vehicle (n=8) 3 days following oocyte retrieval during their donor stimulation cycle. Endometrial biopsies were performed 2 days later, followed by either RNA isolation or tissue fixation in formalin and paraffin embedding. PARTICIPANTS/MATERIALS, SETTING, METHODS: Reverse transcription of total RNA from endometrial biopsies generated cDNA, which was used for analysis in the endometrial receptivity array (ERA; n = 5/group) or quantitative RT-PCR to determine relative expression of ESR1, PGR, C3 and NOTCH1. Tissue sections were stained with hematoxylin and eosin followed by blinded staging analysis for dating of endometrial glands and stroma. Immunostaining for ESR1, PGR, α-SMA, C3 and NOTCH1 was performed to determine their tissue localization. MAIN RESULTS AND THE ROLE OF CHANCE: Intrauterine hCG infusion was associated with endometrial synchrony and reprograming of stromal development following ovarian stimulation. ESR1 and PGR were significantly elevated in the endometrium of hCG-treated patients, consistent with earlier staging. The ERA did not predict an overall positive impact of intrauterine hCG on endometrial receptivity. However, ACTA2, encoding α-SMA was significantly increased in response to intrauterine hCG. Similar to the hCG-treated non-human primate, sub-epithelial and peri-vascular α-SMA expression was induced in women following hCG infusion. Other known targets of hCG in the baboon were also found to be increased, including C3 and NOTCH1, which have known roles in endometrial receptivity. LIMITATIONS, REASONS FOR CAUTION: This study differs from our previous work in the hCG-treated non-human primate along with clinical studies in infertile patients. Specifically, we performed a single intrauterine infusion in oocyte donors instead of either continuous hCG via an osmotic mini-pump in the baboon or infusion followed by blastocyst-derived hCG in infertile women undergoing embryo transfer. Therefore, the full impact of intrauterine hCG in promoting endometrial receptivity may not have been evident. WIDER IMPLICATIONS OF THE FINDINGS: Our findings suggest a potential clinical benefit for intrauterine hCG prior to embryo transfer on Day 3 in counteracting endometrial dyssynchrony from ovarian stimulation and promoting expression of markers important for stromal survival. Finally, there were no obvious negative effects of intrauterine hCG treatment. STUDY FUNDING/COMPETING INTERESTS: Funding for this work was provided by NICHD R01 HD042280 (A.T.F.) and NICHD F30 HD082951 (M.R.S.). C.S. and P.D.-G are co-inventors of the patented ERA, which is owned by IGENOMIX SL and was used in this study, and C.S. is a shareholder in IGENOMIX SL. M.R.-A. is employed by IGENOMIX SL. No other authors have any conflicts of interest to report. TRIAL REGISTRATION NUMBER: This study was registered with ClinicalTrials.gov (NCT01786252). TRIAL REGISTRATION DATE: 5 February 2013. DATE OF FIRST PATIENT'S ENROLLMENT: 10 May 2013.

Deciphering the proteomic signature of human endometrial receptivity.

STUDY QUESTION: Are there any proteomic differences between receptive (R) and non-receptive (NR) endometrial receptivity array (ERA)-diagnosed endometria obtained on the same day of a hormonal replacement therapy (HRT) treatment cycle? SUMMARY ANSWER: There is a different proteomic signature between R and NR ERA-diagnosed endometrium obtained on the same day of HRT cycles. WHAT IS KNOWN ALREADY: The human endometrial transcriptome has been extensively investigated in the last decade resulting in the development of a new diagnostic test based on the transcriptomic signature of the window of implantation (WOI). Much less is known about the proteomics derived from the transcripts present during the WOI. STUDY DESIGN, SIZE, AND DURATION: This study was a basic proteomic analysis of human endometrial biopsies taken from twelve IVF patients. PARTICIPANTS/MATERIALS, SETTING, AND METHODS: Human endometrial biopsies were collected during HRT cycles after 5 days of progesterone (P) administration, and diagnosed as receptive (R; n = 6) or non-receptive (NR; n = 6) by the ERA test. Endometrial proteins were extracted, labelled and separated using differential in-gel electrophoresis (DIGE). Proteins were identified using mass spectrometry, followed up by in silico analysis. Validation studies using western blots and immunolocalization were performed for the progesterone receptor membrane component 1 (PGRMC1) and annexin A6 (ANXA6) proteins. MAIN RESULTS AND THE ROLE OF CHANCE: DIGE analysis followed by protein identification by MALDI-MS and database searches revealed 24 differentially expressed proteins in R versus NR samples. In silico analysis showed two pathways which were significantly different between R and NR samples. Expression of PGRMC1 and ANXA6 was validated and localized by western blots and immunohistochemistry. These results highlight these proteins as key targets likely to be important in the comprehension of human endometrial receptivity. LIMITATIONS, REASONS FOR CAUTION: This was mainly a descriptive study with no functional studies on the proteins found. We also used a low number of human endometrial samples for the DIGE analysis. WIDER IMPLICATIONS OF THE FINDINGS: This study identified the proteomic profile associated with receptive or non-receptive human endometria. Our findings suggest that although histological dating indicates a putative 'receptive' status within the WOI, a different transcriptomic and proteomic profile is observed in these samples. We should move towards using more personalized WOIs, where identification of the correct endometrial receptivity status, and consequently the success of IVF, relies on individual molecular signatures rather than traditional endometrial dating. STUDY FUNDING/COMPETING INTERESTS: F.D.'s participation in this work was supported by the Spanish Ministry of Economy and Competitiveness, through the Miguel Servet Programme (CP13/00075) co-founded by FEDER. The project was also supported by a grant from the Spanish Ministry of Economy and Competitiveness, through the FIS Programme (PI12/00450). The authors have no financial/commercial conflicts of interest to declare.

Transcriptomics of the human endometrium.

During the mid-secretory phase, the endometrium acquires the receptive phenotype, which corresponds to the only period throughout the endometrial cycle in which embryo implantation is viable. Endometrial receptivity is a crucial process and even more important in Assisted Reproductive Technologies (ART) where embryo-endometrial synchronization is coordinated through embryo transfer timing. Over the last decade, transcriptomic analyses performed on the human endometrium have shown that specific genomic signatures can be used to successfully phenotype different phases of the menstrual cycle including the receptive stage, independently of the histological appereance of the endometrial tissue. In this paper, we review current evidence demonstrating that endometrial transcriptomics objectively identifies the implantation window in a personalized manner, opening the field for the diagnosis of the endometrial factor in ART and moving to stratified medicine at this level, using microarray technology and soon high-throughput next generation sequencing coupled with functional and systems genomics approach.

The endometrial receptivity array for diagnosis and personalized embryo transfer as a treatment for patients with repeated implantation failure.

OBJECTIVE: To demonstrate the clinical value of the endometrial receptivity array (ERA) in patients with repeated implantation failure (RIF), for guiding their personalized embryo transfer (pET) as a novel therapeutic strategy. DESIGN: Prospective interventional multicenter clinical trial. SETTING: University-affiliated infertility and private clinics. PATIENT(S): Eighty-five RIF patients and 25 comparison patients. INTERVENTION(S): Endometrial sampling and pET guided by ERA. MAIN OUTCOME MEASURE(S): A receptive (R) or nonreceptive (NR) endometrial status according to ERA. Pregnancy (PR) and implantation (IR) rates after pET. RESULT(S): The ERA test gave an R result of 74.1% in RIF patients versus 88% in control subjects. Clinical follow-up was possible in 29 RIF patients, in whom pET was performed, resulting in 51.7% PR and 33.9% IR. The IRs and PRs in the 6 months after the biopsy showed that pregnancy was not related to the local injury. Twenty-two RIF patients (25.9%) were NR, and in 15 of them a second ERA validated a displacement of the window of implantation (WOI). In eight of them, pET was performed on the day designated by the ERA, resulting in 50.0% PR and 38.5% IR. These results should be considered as preliminary. CONCLUSION(S): There is an increased percentage of WOI displacement in RIF patients compared with comparison group patients, leading to the concept of pET as a therapeutic strategy. Rescue of NR patients by pET in a displaced WOI results in similar PR and IR.