Repeated implantation failure: clinical approach

Subcutaneous G-CSF administration improves IVF outcomes in patients with recurrent implantation failure presenting a KIR/HLA-C mismatch

RESEARCH QUESTION

Despite advances in assisted reproductive technologies, many blastocysts are lost unexpectedly during implantation. Alterations in maternal immune tolerance towards fetal antigens may contribute to adverse IVF outcomes. The purpose of this study is to evaluate whether administering Granulocyte Colony-Stimulating Factor (G-CSF) to couples with a Human Leukocyte Antigen/Killer-Cell Immunoglobulin-Like Receptor (HLA/KIR) mismatch could positively modulate the implantation process in patients with recurrent implantation failure (RIF). A KIR/HLA-C mismatch occurs when the interaction between KIRs and HLA-C causes an inhibition of NK cells, which may result in reduced G-CSF secretion leading to impaired placentation and increased risk of miscarriage, pre-eclampsia and fetal growth restriction.

DESIGN

A retrospective monocentric cohort study conducted at the IVI Clinic in Rome, including women with a history of at least two failed blastocyst transfers. Couples underwent KIR and HLA-C testing. Couples with a KIR/HLA-C mismatch received G-CSF subcutaneously up to week nine of gestation. The mismatch included cases with inhibitory KIR genotypes and HLA-C2C2 females with HLA-C1C1, or C1C2 males or HLA-C1C2 females with male HLA-C2C2. The reproductive outcomes were assessed, and the logistic regression models controlled for potential confounders affecting IVF outcomes.

RESULTS

79 patients with RIF and a KIR/HLA-C mismatch were included in the study. 30 patients were administered G-CSF, and 49 received no treatment. In the univariate analysis, no statistically significant differences were reported in the reproductive outcomes after IVF between the women treated with G-CSF and the control group. However, the logistic regression analysis that controlled for confounding factors showed that patients treated with subcutaneous G-CSF had statistically significant higher ongoing-pregnancy (aOR=3.808) and live-birth (aOR=4.998) rates, and a lower miscarriage rate (aOR=0.057). No statistically significant differences were found in other reproductive outcomes.

CONCLUSION

The use of subcutaneous G-CSF in patients with a KIR/HLA-C mismatch undergoing IVF may reduce miscarriage and improve live-birth rates. G-CSF may modulate NK-mediated immune mechanisms and improve trophoblast invasion and development. Randomized trials are warranted to validate these findings and enhance the chances of successful pregnancies in couples with an immunological mismatch.

Using Machine Learning to Construct the Blood-Follicle Distribution Models of Various Trace Elements and Explore the Transport-Related Pathways with Multiomics Data

Permeabilities of various trace elements (TEs) through the blood-follicle barrier (BFB) play an important role in oocyte development. However, it has not been comprehensively described as well as its involved biological pathways. Our study aimed to construct a blood-follicle distribution model of the concerned TEs and explore their related biological pathways. We finally included a total of 168 women from a cohort of in vitro fertilization-embryo transfer conducted in two reproductive centers in Beijing City and Shandong Province, China. The concentrations of 35 TEs in both serum and follicular fluid (FF) samples from the 168 women were measured, as well as the multiomics features of the metabolome, lipidome, and proteome in both plasma and FF samples. Multiomics features associated with the transfer efficiencies of TEs through the BFB were selected by using an elastic net model and further utilized for pathway analysis. Various machine learning (ML) models were built to predict the concentrations of TEs in FF. Overall, there are 21 TEs that exhibited three types of consistent BFB distribution characteristics between Beijing and Shandong centers. Among them, the concentrations of arsenic, manganese, nickel, tin, and bismuth in FF were higher than those in the serum with transfer efficiencies of 1.19-4.38, while a reverse trend was observed for the 15 TEs with transfer efficiencies of 0.076-0.905, e.g., mercury, germanium, selenium, antimony, and titanium. Lastly, cadmium was evenly distributed in the two compartments with transfer efficiencies of 0.998-1.056. Multiomics analysis showed that the enrichment of TEs was associated with the synthesis and action of steroid hormones and the glucose metabolism. Random forest model can provide the most accurate predictions of the concentrations of TEs in FF among the concerned ML models. In conclusion, the selective permeability through the BFB for various TEs may be significantly regulated by the steroid hormones and the glucose metabolism. Also, the concentrations of some TEs in FF can be well predicted by their serum levels with a random forest model.

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.

Predictive models of recurrent implantation failure in patients receiving ART treatment based on clinical features and routine laboratory data

STUDY QUESTION

The objective was to construct a model for predicting the probability of recurrent implantation failure (RIF) after assisted reproductive technology (ART) treatment based on the clinical characteristics and routine laboratory test data of infertile patients. A model was developed to predict RIF. The model showed high calibration in external validation, helped to identify risk factors for RIF, and improved the efficacy of ART therapy.

WHAT IS KNOWN ALREADY

Research on the influencing factors of RIF has focused mainly on embryonic factors, endometrial receptivity, and immune factors. However, there are many kinds of examinations regarding these aspects, and comprehensive screening is difficult because of the limited time and economic conditions. Therefore, we should try our best to analyse the results of routine infertility screenings to make general predictions regarding the occurrence of RIF.

STUDY DESIGN, SIZE, DURATION

A retrospective study was conducted with 5212 patients at the Reproductive Center of the First Affiliated Hospital of USTC from January 2018 to June 2022.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study included 462 patients in the RIF group and 4750 patients in the control group. The patients' basic characteristics, clinical treatment data, and laboratory test indices were compared. Logistic regression was used to analyse RIF-related risk factors, and the prediction model was evaluated by receiver operating characteristic (ROC) curves and the corresponding areas under the curve (AUCs). Further analysis of the influencing factors of live births in the first cycle of subsequent assisted reproduction treatment in RIF patients was performed, including the live birth subgroup (n = 116) and the no live birth subgroup (n = 200).

MAIN RESULTS AND THE ROLE OF CHANCE

(1) An increased duration of infertility (1.978; 95% CI, 1.264-3.097), uterine cavity abnormalities (2.267; 95% CI, 1.185-4.336), low AMH levels (0.504; 95% CI, 0.275-0.922), insulin resistance (3.548; 95% CI, 1.931-6.519), antinuclear antibody (ANA)-positive status (3.249; 95% CI, 1.20-8.797) and anti-β2-glycoprotein I antibody (A-β2-GPI Ab)-positive status (5.515; 95% CI, 1.481-20.536) were associated with an increased risk of RIF. The area under the curve of the logistic regression model was 0.900 (95% CI, 0.870-0.929) for the training cohort and 0.895 (95% CI, 0.865-0.925) for the testing cohort. (2) Advanced age (1.069; 95% CI, 1.015-1.126) was a risk factor associated with no live births after the first cycle of subsequent assisted reproduction treatment in patients with RIF. Blastocyst transfer (0.365; 95% CI = 0.181-0.736) increased the probability of live birth in subsequent cycles in patients with RIF. The area under the curve of the logistic regression model was 0.673 (95% CI, 0.597-0.748).

LIMITATIONS, REASONS FOR CAUTION

This was a single-centre regression study, for which the results need to be evaluated and verified by prospective large-scale randomized controlled studies. The small sample size for the analysis of factors influencing pregnancy outcomes in subsequent assisted reproduction cycles for RIF patients resulted in the inclusion of fewer covariates, and future studies with larger samples and the inclusion of more factors are needed for assessment and validation.

WIDER IMPLICATIONS OF THE FINDINGS

Prediction of embryo implantation prior to transfer will facilitate the clinical management of patients and disease prediction and further improve ART treatment outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the General Project of the National Natural Science Foundation of China (Nos. 82,201,792, 82,301,871, 81,971,446, and 82,374,212) and the Natural Science Foundation of Anhui Province (No. 2208085MH206). There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

This study was registered with the Chinese Clinical Trial Register (Clinical Trial Number: ChiCTR1800018298 ).

A disrupted FOXP3 transcriptional signature underpins systemic regulatory T cell insufficiency in early pregnancy failure

Regulatory T (Treg) cell defects are implicated in disorders of embryo implantation and placental development, but the origins of Treg cell dysfunction are unknown. Here, we comprehensively analyzed the phenotypes and transcriptional profile of peripheral blood Treg cells in individuals with early pregnancy failure (EPF). Compared to fertile subjects, EPF subjects had 32% fewer total Treg cells and 54% fewer CD45RA+CCR7+ naive Treg cells among CD4+ T cells, an altered Treg cell phenotype with reduced transcription factor FOXP3 and suppressive marker CTLA4 expression, and lower Treg:Th1 and Treg:Th17 ratios. RNA sequencing demonstrated an aberrant gene expression profile, with upregulation of pro-inflammatory genes including CSF2, IL4, IL17A, IL21, and IFNG in EPF Treg cells. In silico analysis revealed 25% of the Treg cell dysregulated genes are targets of FOXP3. We conclude that EPF is associated with systemic Treg cell defects arising due to disrupted FOXP3 transcriptional control and loss of lineage fidelity.

The reproductive potential of vitrified-warmed euploid embryos declines following repeated uterine transfers

BACKGROUND

Recurrent implantation failure (RIF) represents a vague clinical condition with an unclear diagnostic challenge that lacks solid scientific underpinning. Although euploid embryos have demonstrated consistent implantation capabilities across various age groups, a unanimous agreement regarding the advantages of preimplantation genetic testing for aneuploidy (PGT-A) in managing RIF is absent. The ongoing discussion about whether chromosomal aneuploidy in embryos significantly contributes to recurrent implantation failure remains unsettled. Despite active discussions in recent times, a universally accepted characterization of recurrent implantation failure remains elusive. We aimed in this study to measure the reproductive performance of vitrified-warmed euploid embryos transferred to the uterus in successive cycles.

METHODS

This observational cohort study included women (n = 387) with an anatomically normal uterus who underwent oocyte retrieval for PGT-A treatment with at least one biopsied blastocyst, between January 2017 and December 2021 at a university-affiliated public fertility center. The procedures involved in this study included ICSI, blastocyst culture, trophectoderm biopsy and comprehensive 24-chromosome analysis of preimplantation embryos using Next Generation Sequencing (NGS). Women, who failed a vitrified-warmed euploid embryo transfer, had successive blastocyst transfer cycles (FET) for a total of three using remaining cryopreserved euploid blastocysts from the same oocyte retrieval cycle. The primary endpoints were sustained implantation rate (SIR) and live birth rate (LBR) per vitrified-warmed single euploid embryo. The secondary endpoints were mean euploidy rate (m-ER) per cohort of biopsied blastocysts from each patient, as well as pregnancy and miscarriage rates.

RESULTS

The mean age of the patient population was 33.4 years (95% CI 32.8-33.9). A total of 1,641 embryos derived from the first oocyte retrieval cycle were biopsied and screened. We found no associations between the m-ER and the number of previous failed IVF cycles among different ranges of maternal age at oocyte retrieval (P = 0.45). Pairwise comparisons showed a significant decrease in the sustained implantation rate (44.7% vs. 30%; P = 0.01) and the livebirth rate per single euploid blastocyst (37.1% vs. 25%; P = 0.02) between the 1st and 3rd FET. The cumulative SIR and LBR after up to three successive single embryo transfers were 77.1% and 68.8%, respectively. We found that the live birth rate of the first vitrified-warmed euploid blastocyst transferred decreased significantly with the increasing number of previously failed IVF attempts by categories (45.3% vs. 35.8% vs. 27.6%; P = 0.04). A comparable decrease in sustained implantation rate was also observed but did not reach statistical significance (50% vs. 44.2 vs. 37.9%; P = NS). Using a logistic regression model, we confirmed the presence of a negative association between the number of previous IVF failed attempts and the live birth rate per embryo transfer cycle (OR = 0.76; 95% CI 0.62-0.94; P = 0.01).

CONCLUSIONS

These findings are vital for enhancing patient counseling and refining management strategies for individuals facing recurrent implantation failure. By tailoring interventions based on age and ovarian reserve, healthcare professionals can offer more personalized guidance, potentially improving the overall success rates and patient experiences in fertility treatments.

TRIAL REGISTRATION NUMBER

N/A.

Endometrial BMP2 Deficiency Impairs ITGB3-Mediated Trophoblast Invasion in Women With Repeated Implantation Failure

BACKGROUND

Repeated implantation failure (RIF) leads to a waste of high-quality embryos and remains a challenge in assisted reproductive technology. During early human placentation, the invasion of trophoblast cells into the decidua is an essential step for the establishment of maternal-fetal interactions and subsequent successful pregnancy. Bone morphogenetic protein 2 (BMP2) has been reported to regulate endometrial receptivity and promote trophoblast invasion. However, whether there is dysregulation of endometrial BMP2 expression in patients with RIF remains unknown. Additionally, the molecular mechanisms underlying the effects of BMP2 on human trophoblast invasion and early placentation remain to be further elucidated.

METHODS

Midluteal phase endometrial samples were biopsied from patients with RIF and from routine control in vitro fertilization followed by quantitative polymerase chain reaction and immunoblotting analyses. Human trophoblast organoids, primary human trophoblast cells, and an immortalized trophoblast cell line (HTR8/SVneo) were used as study models.

RESULTS

We found that BMP2 was aberrantly low in midluteal phase endometrial tissues from patients with RIF. Recombinant human BMP2 treatment upregulated integrin β3 (ITGB3) in a SMAD2/3-SMAD4 signaling-dependent manner in both HTR8/SVneo cells and primary trophoblast cells. siRNA-mediated integrin β3 downregulation reduced both basal and BMP2-upregulated trophoblast invasion and vascular mimicry in HTR8/SVneo cells. Importantly, shRNA-mediated ITGB3 knockdown significantly decreased the formation ability of human trophoblast organoids.

CONCLUSION

Our results demonstrate endometrial BMP2 deficiency in patients with RIF. ITGB3 mediates both basal and BMP2-promoted human trophoblast invasion and is essential for early placentation. These findings broaden our knowledge regarding the regulation of early placentation and provide candidate diagnostic and therapeutic targets for RIF clinical management.

Tacrolimus treatment in women with repeated implantation failures

Background

Tacrolimus is an immunosuppressive drug that works as a calcineurin inhibitor to improve the reproductive outcomes for women who have experienced multiple implantation failures (RIF) and show elevated type 1 helper T (Th1)/Th2 cell ratios.

Methods

In the first part of this review, we indicate how we re-evaluated the cut-off index for selecting the participants in a tacrolimus regimen via transferred euploid blastocysts. In the second part, we cite cases where tacrolimus has improved the live birth rate for women who have experienced recurrent pregnancy losses (PRL) and we introduce the utility of tacrolimus treatment to prevent obstetrical complications.

Main Findings

After reconsideration of the cut-off index (Th1/Th2 ≥ 11.8), however, the pregnancy rates of women with tacrolimus were significantly higher than those of women without tacrolimus. The PRL women treated with tacrolimus showed significantly lower rates of biochemical pregnancy, but higher live-birth rates compared with women who were not treated with tacrolimus. Moreover, prior severe obstetrical complications could be controlled via the administration of tacrolimus during pregnancy.

Conclusion

Tacrolimus has become indispensable in the field of solid-organ transplantation, and in the near future, it should become an essential agent in the reproductive field, as well.

The efficacy of intrauterine infusion of platelet rich plasma in women undergoing assisted reproduction: a systematic review and meta-analysis

BACKGROUND

Platelet-rich plasma (PRP) is an autologous platelet concentration recently used in the reproductive field. Studies had conflicting results regarding its effect on pregnancy outcomes. We aimed to solve the debate on the safety and efficacy of PRP in women undergoing assisted reproduction and assess the influence of covariates on the outcomes of PRP infusion.

METHODS

We searched PubMed, Scopus, Cochrane, and Web of Science in May 2023. We included randomized and non-randomized clinical trials as well as cohort studies assessing intrauterine PRP in sub fertile women undergoing assisted reproduction (IVF/ICSI). For the quality assessment, We used the Cochrane Risk of Bias Tool 1, the ROBINS-I tool, and the Newcastle-Ottawa Scale. We pooled the data using RevMan version 5.4.

RESULTS

The data from 23 studies were pooled. PRP had favorable outcomes compared with the control group on clinical pregnancy rate (RR: 1.84, 95% CI 1.62 to 2.09; P < 0.00001), live birth rate (RR: 1.75, 95% CI: 1.24 to 2.47; P = 0.001), and miscarriages (RR: 0.51, 95% CI: 0.36 to 0.72; P = 0.0002). Women with repeated implantation failure had a significantly improved clinical pregnancy rate (RR: 1.83, 95% CI: 1.49 to 2.24; P < 0.00001), live birth rate (RR:1.83, 95% CI: 1.33 to 2.51; P = 0.002), and miscarriage rate (RR: 0.46, 95% CI: 0.31 to 068; P = 0.0001).

CONCLUSION

PRP showed promising results in assisted reproductive techniques. Further large and multicenter RCTs are required to compare the doses of PRP while identifying the specific population with the most benefits from PRP.

Comparison of the efficacy of depot GnRH agonist protocol and the GnRH antagonist protocol in patients with repeated IVF failure: a retrospective cohort study

The aims of the research were (i) to compare the clinical outcome of IVF using follicular-phase depot gonadotropin-releasing hormone (GnRH) agonist (depot agonist) protocol and GnRH antagonist protocol in patients with repeated IVF failure (RIF), (ii) to discover the optimal ovarian stimulation protocol for this group of low prognosis patients. 801 RIF patients with normal ovarian reserve receiving in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) were included in this retrospective study. Among them, 492 patients were treated with the depot agonist protocol, and the remaining 309 patients with the antagonist protocol. Multivariable logistic regression analysis was used to find the predictor(s) of the chance of live birth. Higher live birth rate (LBR) and clinical pregnancy rate (CPR) in fresh embryo transfer (ET) cycles were associated with the use of depot agonist compared with the antagonist protocols (44.81% vs. 27.27%, 54.64% vs. 34.93%, respectively; both p < 0.01) and depot agonist protocol was a strong predictor of live birth (OR = 2.182, 95% CI 1.355-3.514, p < 0.01). The CPR in thawed ET cycles was not significantly different between the two groups (38.12% vs. 45.26%, p > 0.05). A higher cumulative live birth rate (CLBR) was achieved in the depot agonist group (46.59% vs. 35.21%, p < 0.01). Beneficial endometrial receptivity in the depot agonist protocol contributed to a higher LBR in fresh ET cycles, rendering this protocol the preferred option in the treatment of RIF patients.

Impact of body mass index on peripheral and uterine immune status in the window of implantation in patients with recurrent reproductive failure

This study aimed to investigate whether maternal obesity affects the immune status of peripheral blood and endometrium in patients with recurrent reproductive failure classified according to their body mass index (BMI). A total of 228 repeated implantation failure (RIF) and 266 recurrent miscarriage (RM) patients were enrolled in the study and further subdivided into three groups according to their BMI: (i) normal weight (18.5≤ BMI <23); (ii) overweight (23≤ BMI <25); and (iii) obese (BMI ≥25). Peripheral blood and endometrium samples were collected in the mid-luteal phase before IVF treatment or natural pregnancy. Peripheral immunocytes were analyzed by flow cytometry, while uterine immune cells were subjected to immunohistochemistry. In RM patients, significantly increased peripheral helper T cells and decreased cytotoxic T cells, NK cells were observed in the obese group compared with the normal-weight group. Meanwhile, in the endometrium, the percentage of NK cell, macrophage cell, M2 macrophage cell, and Treg cell significantly reduced with increased BMI in RIF patients, and the percentage of NK cell and M2 macrophage cell significantly decreased with increased BMI in RM patients. In conclusion, obesity may cause endometrial immune disorder in recurrent reproductive failure women, but was only associated with the peripheral immune change in RM patients.

Pregnancy by Oocyte Donation: Reviewing Fetal-Maternal Risks and Complications

Oocyte donation (OD) has greatly improved over the last three decades, becoming a preferred practice of assisted reproductive technology (ART) for infertile women wishing for motherhood. Through OD, indeed, it has become possible to overcome the physiological limitation due to the ovarian reserve (OR) exhaustion as well as the poor gamete reliability which parallels the increasing age of women. However, despite the great scientific contribution related to the success of OD in the field of infertility, this practice seems to be associated with a higher rate of major risky events during pregnancy as recurrent miscarriage, infections and placental diseases including gestational hypertension, pre-eclampsia and post-partum hemorrhage, as well as several maternal-fetal complications due to gametes manipulation and immune system interaction. Here, we will revisit this questioned topic since a number of studies in the medical literature focus on the successful aspects of the OD procedure in terms of pregnancy rate without, however, neglecting the risks and complications potentially linked to external manipulation or heterologous implantation.

Association of angiotensin II and receptors in peri-implantation endometrium with microvessel density and pregnancy outcomes of women with recurrent implantation failure after embryo transfer

Purpose

Investigate whether local angiotensin II (AngII) and its AngII type 1 and 2 receptors (AT1R, AT2R) in the endometrium are different and correlate with microvessel density in women with reproductive failure and pregnancy outcomes.

Methods

Endometrium during the window of implantation from 40 women with recurrent miscarriage (RM) and 40 with recurrent implantation failure (RIF) were compared with 27 fertile women. Peri-implantation endometrium from 54 women prior to euploid embryo transfer were collected and compared in women with successful pregnancy and unsuccessful pregnancy.

Results

Compared with fertile women, expression of AT2R was significantly lower, while AT1R/AT2R expression ratio was significantly higher in the stroma of the RIF group. Endometrium arteriole MVD was significantly lower and negatively correlated with the AT1R/AT2R expression ratio in the stroma of the RIF group. No significant differences and correlations were found in the RM group. Compared with the pregnancy group, expression of AT1R and AT2R were significantly lower in all compartments, but only AT1R/AT2R ratio was significantly higher in the stroma of the non-pregnancy group. Similarly, endometrium arteriole MVD was also significantly lower and negatively correlated with the AT1R/AT2R ratio in the stroma of the non-pregnancy group.

Conclusion

Local renin-angiotensin system is dysregulated in peri-implantation endometrium and associated with abnormal angiogenesis in RIF and poor implantation outcome after embryo transfer.

Efficacy of granulocyte colony-stimulating factor for infertility undergoing IVF: a systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the effectiveness of granulocyte colony-stimulating factor (G-CSF) for infertility and recurrent spontaneous abortion.

METHODS

Existing research was searched in PubMed, Embase and Cochrane Library till Dec 2021. Randomized control trials (RCTs) that compared G-CSF administration with the control group in infertility women undergoing IVF were included. The primary outcomes included clinical pregnancy rate; the secondary outcomes included live birth rate, abortion ratebiochemical pregnancy rate, embryo implantation rate, as well as endometrial thickness.

RESULT(S)

20 RCTs were included in this study. G-CSF increased the clinical pregnancy rate (RR = 1.85; 95% CI: 1.07, 3.18) and the endometrial thickness (MD = 2.25; 95% CI: 1.58,2.92;) in patients with thin endometrium undergoing IVF. G-CSF increased the biochemical pregnancy rate (RR = 2.12; 95% CI: 1.54, 2.93), the embryo implantation rate (RR = 2.51; 95% CI: 1.82, 3.47) and the clinical pregnancy rate (RR = 1.93; 95% CI: 1.63, 2.29) in patients with a history of repeated implantation failure undergoing IVF. No differences were found in pregnancy outcomes of general IVF patients.

CONCLUSIONS

Granulocyte colony-stimulating factor is likely to be a potential option for infertility women undergoing IVF with thin endometrium or recurrent implantation failure .

TRIAL REGISTRATION

Retrospectively registered (The PROSPERO registration number: CRD42022360161).

Deep learning analysis of endometrial histology as a promising tool to predict the chance of pregnancy after frozen embryo transfers

PURPOSE

Endometrial histology on hematoxylin and eosin (H&E)-stained preparations provides information associated with receptivity. However, traditional histological examination by Noyes' dating method is of limited value as it is prone to subjectivity and is not well correlated with fertility status or pregnancy outcome. This study aims to mitigate the weaknesses of Noyes' dating by analyzing endometrial histology through deep learning (DL) algorithm to predict the chance of pregnancy.

METHODS

Endometrial biopsies were taken during the window of receptivity from healthy volunteers in natural menstrual cycles (group A) and infertile patients undergoing mock artificial cycles (group B). H&E staining was performed followed by whole slide image scanning for DL analysis.

RESULTS

In a proof-of-concept trial to differentiate group A (n=24) vs. B (n=37), a DL-based binary classifier was trained, cross-validated, and achieved 100% for accuracy. Patients in group B underwent subsequent frozen-thawed embryo transfers (FETs) and were further categorized into "pregnant (n=15)" or "non-pregnant (n=18)" sub-groups based on the outcomes. In the following trial to predict pregnancy outcome in group B, the DL-based binary classifier yielded 77.8% for accuracy. Its performance was further validated by an accuracy of 75% in a "held-out" test set where patients had euploid embryo transfers. Furthermore, the DL model identified histo-characteristics including stromal edema, glandular secretion, and endometrial vascularity as important features related to pregnancy prediction.

CONCLUSIONS

DL-based endometrial histology analysis demonstrated its feasibility and robustness in pregnancy prediction for patients undergoing FETs, indicating its value as a prognostic tool in fertility treatment.

Association between endometrial blood and clinical outcome in frozen single blastocyst transfer cycles

Background: The success of embryo transfer cycle depends mainly on the quality of embryo and endometrial receptivity. Ultrasound examination is still the most widely used non-invasive evaluation method for its advantages of convenience, non-invasiveness and repeatability. Ultrasound-measured endometrial blood flow is one of the important evaluation indicators of morphology. Aims: To investigate the effect of the number of endometrial blood flow branches on pregnancy outcome of frozen-thawed embryo transfer cycles which have undergoing hormone replacement therapy (HRT-FET). Material and methods: A retrospective cohort study was performed looking at a total of 1390 HRT-FET cycles from our reproductive medicine center between January 2017 to December 2021, which transferred one blastocyst frozen on day 5 with good quality in morphology. Associations between endometrial blood flow branches and pregnancy outcomes were evaluated with multivariable linear regression analysis. Results: The number of endometrial blood flow branches was independently associated with clinical pregnancy (OR 1.10; 95% CI 1.02-1.20). After adjusting for potential confounders, the effect size (odds ratio) was 1.09 (95% CI 1.00-1.19), and the results showed that the clinical pregnancy rate and live birth rate of T2 and T3 groups were significantly higher than those in group T1 (p < 0.05). Subgroup analysis showed that a consistent association between the endometrial blood flow branches and clinical pregnancy in all subgroups. Conclusion: Our study provided evidence for the influence of endometrial blood flow on pregnancy outcomes. There may be an independent association between the number of endometrial blood flow branches and pregnancy outcomes in frozen-thawed single blastocyst transfer cycles.

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 .

Cervical Secretion Methylation Is Associated with the Pregnancy Outcome of Frozen-Thawed Embryo Transfer

The causes of implantation failure remain a black box in reproductive medicine. The exact mechanism behind the regulation of endometrial receptivity is still unknown. Epigenetic modifications influence gene expression patterns and may alter the receptivity of human endometrium. Cervical secretions contain endometrial genetic material, which can be used as an indicator of the endometrial condition. This study evaluates the association between the cervical secretion gene methylation profile and pregnancy outcome in a frozen-thawed embryonic transfer (FET) cycle. Cervical secretions were collected from women who entered the FET cycle with a blastocyst transfer (36 pregnant and 36 non-pregnant women). The DNA methylation profiles of six candidate genes selected from the literature review were measured by quantitative methylation-specific PCR (qMSP). Bioinformatic analysis of six selected candidate genes showed significant differences in DNA methylation between receptive and pre-receptive endometrium. All candidate genes showed different degrees of correlation with the pregnancy outcomes in the logistic regression model. A machine learning approach showed that the combination of candidate genes' DNA methylation profiles could differentiate pregnant from non-pregnant samples with an accuracy as high as 86.67% and an AUC of 0.81. This study demonstrated the association between cervical secretion methylation profiles and pregnancy outcomes in an FET cycle and provides a basis for potential clinical application as a non-invasive method for implantation prediction.

The Dynamics of miR-449a/c Expression during Uterine Cycles Are Associated with Endometrial Development

The human endometrium is a highly dynamic tissue. Increasing evidence has shown that microRNAs (miRs) play essential roles in human endometrium development. Our previous assay, based on small RNA-sequencing (sRNA-seq) indicated the complexity and dynamics of numerous sequence variants of miRs (isomiRs) that can act together to control genes of functional relevance to the receptive endometrium (RE). Here, we used a greater average depth of sRNA-seq to detect poorly expressed small RNAs. The sequencing data confirmed the up-regulation of miR-449c and uncovered other members of the miR-449 family up-regulated in RE-among them miR-449a, as well as several isoforms of both miR-449a and miR-449c, while the third family member, miR-449b, was not identified. Stem-looped RT-qPCR analysis of miR expression at four-time points of the endometrial cycle verified the increased expression of the miR-449a/c family members in RE, among which the 5' isoform of miR-449c-miR-449c.1 was the most strongly up-regulated. Moreover, we found in a case study that the expression of miR-449c.1 and its precursor correlated with the histological assessment of the endometrial phase and patient age. We believe this study will promote the clinical investigation and application of the miR-449 family in the diagnosis and prognosis of human reproductive diseases.

Cutting-edge techniques provide insights regarding repeated implantation failure patients

RESEARCH QUESTION

Can time-lapse parameters and the transcriptional profile of cumulus cells be used to achieve a more stringent and non-invasive method of embryo assessment and to identify possible factors affecting the embryo's ability to implant in repeated implantation failure (RIF) patients?

DESIGN

A total of 190 embryos from 18 oocyte donors and 145 embryos from 15 RIF patients were evaluated based on time-lapse parameters. Three morphokinetic parameters including T5 (time to reach five cells), T3 (time to reach three cells) and CC2 (time to two to three cells) were recorded for all embryos. Embryos that had all three parameters in the normal range were graded as high quality and comparison between these parameters were compared in high-quality embryos between two groups. The transcriptional profile of cumulus cells related to high-quality embryos of both groups were analysed by RNA sequencing and compared. Finally, the possible relationship between differentially expressed genes and time-lapse parameters was examined.

RESULTS

T5 was significantly lower in the RIF group than the donor group (P = 0.011). The cumulus cell transcriptome analysis showed 193 genes were down-regulated and 222 genes up-regulated. The mammalian target of rapamycin and the transforming growth factor beta pathways were significantly increased in the RIF group compared to the donor group (P = 0.007 and 0.01, respectively). Vitamin B12 and fatty acid beta-oxidation pathways were also significantly reduced in the RIF group compared to the donor group (P = 0.006 and 0.01, respectively).

CONCLUSIONS

Differences in the transcriptomic profiles of cumulus cells and some morphokinetic parameters may be one of the main factors contributing to unexplained RIF.

Zooming in on the endometrial factor of recurrent implantation failure

Recurrent implantation failure (RIF) is a major limiting factor in the success rates of in-vitro fertilisation despite the remarkable clinical and technological advancement made at improving assisted reproductive technology. The primary purpose of the endometrium is to provide a receptive site for the implantation of the blastocyst and support its growth and subsequent development. Endometrial pathologies such as endometrial polyps, adenomyosis, Asherman's syndrome, chronic endometritis, and congenital Müllerian ducts defect negatively influence the integrity and receptivity of the endometrium, as well as the implantation of the embryo. This review highlights the implications of these endometrial pathologies and their association with RIF.

Immunophenotyping of peripheral blood monocytes could help identify a baseline pro-inflammatory profile in women with recurrent reproductive failure

Recurrent pregnancy loss (RPL) and recurrent implantation failure (RIF) are two well-defined clinical entities, but the role of the monocytes in their pathophysiology needs to be clarified. This study aimed to evaluate the role of the three monocyte subsets (classical, intermediate, and non-classical) and relevant cytokines/chemokines in a cohort of RPL and RIF women to better characterize a baseline proinflammatory profile that could define inflammatory pathophysiology in these two different conditions. We evaluated 108 non-pregnant women: 53 RPL, 24 RIF, and 31 fertile healthy controls (HC). Multiparametric flow cytometry was used to quantify the frequency of surface chemokine receptors (CCR2, CCR5, and CX3CR1) on the monocyte subsets. Cytokines were assessed in plasma samples using a multiplex assay. The CX3CR1⁺ and CCR5⁺ intermediate monocytes were significantly higher in RPL and RIF compared to HC. A significant positive correlation was observed between CX3CR1⁺ intermediate monocytes and IL-17A (P = .03, r = 0.43). The Boruta algorithm followed by a multivariate logistic regression model was used to select the most relevant variables that could help define RPL and RIF: in RPL were CX3CR1 non-classical monocytes, TGF-β1, and CCR5 intermediate monocytes; in RIF: CCR5 intermediate monocytes and TGF-β3. The combination of these variables could predict RPL and RIF with 90 % and 82 %, respectively. Our study suggests that a combination of specific blood monocyte subsets and cytokines could aid in identifying RPL and RIF women with a pro-inflammatory profile. These findings could provide a more integrated understanding of these pathologies. Further investigation and validation in independent cohorts are warranted.

Granulocyte colony stimulating factor versus human chorionic gonadotropin for recurrent implantation failure in intra cytoplasmic sperm injection: a randomized clinical trial

BACKGROUND

Repeated implantation failure (RIF) is defined as the case whereby the transferred embryos fail to implant after several attempts of In vitro fertilization (IVF) which causes a profound impact on the quality of life and financial burden. Some clinical studies have confirmed that Granulocyte colony-stimulating factor (G-CSF) and human chorionic gonadotropin (HCG) can improve pregnancy outcomes and implantation rates. Hence, our study aims to compare the efficacy of G-CSF and HCG on pregnancy outcomes in RIF women who undergo intra-cytoplasmic sperm injection (ICSI).

METHODS

This randomized, single-blinded study was conducted et al.-Azhar University Hospitals, Cairo, Egypt, between 10^th October 2020 and 20^th December 2020. The study included 100 women aged 20-43 years old undergoing ICSI cycles, with a history of RIF. Patients were divided randomly into two groups: group (1): included 50 patients injected with 500 IU of intrauterine HCG on embryo transfer day, and group (2): Included 50 patients injected with G-CSF on the embryo transfer day.

RESULTS

In 100 RIF women, we found a significant improvement in pregnancy outcomes favoring G-CSF over HCG including implantation rate, chemical pregnancy, and clinical pregnancy (P < 0.0001, P = 0.0003, and P = 0.0006, respectively).

CONCLUSION

For the first time, we demonstrated a significant improvement in pregnancy outcomes favoring G-CSF over HCG in terms of implantation rate, chemical pregnancy, and clinical pregnancy.

TRIAL REGISTRATION

The study was registered on Pan African Clinical Trials Registry with the following number: PACTR202010482774275 and was approved on 2^nd October 2020.

Endometrium Immunomodulation to Prevent Recurrent Implantation Failure in Assisted Reproductive Technology

After more than four decades of assisted reproductive technology (ART) practice worldwide, today more than 60% of women undergoing in vitro fertilization (IVF) treatments fail to become pregnant after the first embryo transfer and nearly 20% of patients are suffering from unexplained recurrent implantation failures (RIFs) and repeated pregnancy loss (RPL). The literature reported different causes of RIF–RPL, mainly multifactorial, endometrial and idiopathic. RIF remains a black box because of the complicated categorization and causes of this physio-pathological dysregulation of implantation and pregnancy process after ovarian stimulation. Many options were suggested as solutions to treat RIF–RPL with controversial results on their usefulness. In this article, we reviewed different possible therapeutic options to improve implantation rates and clinical outcomes. Based on our experience we believe that endometrium immunomodulation after intrauterine insemination of activated autologous peripheral blood mononuclear cells (PBMCs) or platelet-rich plasma (PRP) can be a promising therapeutic solution. On the other hand, peripheral lymphocyte balance typing, specific cytokines and interleukins profiling can be proposed as predictive biomarkers of implantation before embryo transfer.

Potential utility of a non-invasive menstrual blood immunophenotype analysis in reproductive medicine

Purpose Can a comprehensive flow cytometry panel be used to assess immunophenotype profiles in menstrual blood of patients experiencing reproductive failure and age matched controls of proven fertility? Methods 58 recurrent pregnancy loss and repeated implantation failure patients, along with 15 age matched controls of proven fertility, had menstrual blood samples obtained within the first 24 hours of the onset of menstruation to non-invasively assess the local immunophenotype. Using a comprehensive multi-parameter flow panel the lymphocyte sub-populations were described and compared. Results Relative to well established peripheral blood immunophenotyping values, distinct lymphocyte population differences were noted between the subgroups. The ratios of CD4+ and CD8+ T-cells were inverted relative to peripheral blood and uterine NK cells represented by CD56bright were distinctly visualised, emphasising the distinction of menstrual and peripheral blood. Relative to controls there were marked increases in CD3+ve T-cells (p=0.009), CD4:CD8 ratio (p=0.004), CD19 B-cells (p=0.026) and CD56dim NK's (p=0.002) in the reproductive failure cases. Conclusions Flow cytometric evaluation can provide a rapid and objective analysis of lymphocyte subpopulations in many forms of tissue and fluid. The findings show significant variations in cellular composition of immune cells indicating a distinct compartment, with differences between cases and controls. Immunological assessment of the menstrual blood immunophenotype, in clinically appropriate patients, may provide insight into the aetiology of adverse reproductive outcome, without the risks and inconveniences associated with a more invasive endometrial biopsy.

Interaction between endometrial microbiota and host gene regulation in recurrent implantation failure

AIM

To learn about the interaction between endometrial microbiota and host gene regulation in recurrent implantation failure.

METHODS

The endometrial microbiota of 111 patients (RIF, 75; CON, 36) was analyzed by using 16 s rRNA sequencing technology. Transcriptome sequencing analysis of the endometrial of 60 patients was performed by using high-throughput sequencing.

RESULTS

We found that the structure and composition of endometrium microbiota community of RIF patients were significantly different from those in control group. The abnormality of microbial structure and composition might interfere with the implantation of embryos by affecting the immune adaptation of the endometrium and the formation of endometrial blood vessels.

CONCLUSIONS

Our research described the host-microbe interaction in RIF. The structure and composition of endometrium microbiota community of RIF patients were significantly different from those in CON group. The abnormality of microbial structure and composition might interfere with the implantation of embryos by affecting the immune adaptation of the endometrium and the formation of endometrial blood vessels.

Advances in the study of HLA class Ib in maternal-fetal immune tolerance

The HLA class Ib molecule is an alloantigen that causes transplant rejection on behalf of individual human and plays an important role in maternal-fetal immune tolerance. Early studies on HLA class Ib focused on the mechanism of HLA-G-induced immune escape, but in recent years, studies on the mechanism of HLA-G have deepened and gradually explored the mechanism of HLA-E and HLA-F, which are also HLA class Ib molecules. In the maternal-fetal interface, trophoblast cells express HLA class Ib molecules to protect the fetus from maternal immune cells by binding to inhibitory receptors of decidual immune cells (DICs) and shifting Th1/Th2 balance toward Th2 bias. Further studies on the molecular mechanism of HLA class Ib molecules provide a reference for its application in the field of clinical assisted reproduction.

A randomized double blind comparison of atosiban in patients with recurrent implantation failure undergoing IVF treatment

BACKGROUND

Patients with recurrent implantation failure (RIF) may have more uterine contractions. Several observational studies suggested that atosiban administration around embryo transfer resulted in higher pregnancy rates in RIF patients. This study aimed to evaluate the effect of atosiban given before fresh embryo transfer on pregnancy outcomes of women with RIF.

METHODS

A prospective, randomized, double-blind controlled clinical trial was performed in IVF center of Shanghai First Maternity and Infant Hospital. According to a computer-generated randomization list, 194 infertile women with RIF received fresh embryo transfer between July 2017 and December 2019 were randomly allocated into the atosiban (n = 97) and the placebo (n = 97) groups. Women in the treatment group received atosiban intravenously about 30 min before embryo transfer with a bolus dose of 6.75 mg over one minute. Those in the placebo group received only normal saline infusion for the same duration.

RESULTS

There was no significant difference in the live birth rate between the atosiban and placebo groups (42.3% vs 35.1%, P = 0.302, RR = 1.206 (0.844-1.723)). No significant differences were found between the two groups in the positive pregnancy test, clinical pregnancy, ongoing pregnancy, miscarriage, multiple pregnancy, ectopic pregnancy and implantation rates. Similar results were found when stratified by the number of embryos previously transferred, number of previous failed embryo transfers, frequency of endometrial peristalsis on embryo transfer day (≥ 3 waves/min) or serum estradiol (E₂) on the day of hCG above the median level. And, there was no correlation between the serum E₂ level on the day of hCG and the frequency of endometrial peristalsis on embryo transfer day. The frequency of endometrial peristalsis on embryo transfer day, total FSH/HMG dosage and duration were the significant factors which independently predicted the likelihood of a live birth.

CONCLUSIONS

These results suggested that atosiban treatment before fresh embryo transfer might not improve the live birth rate in RIF patients.

TRIAL REGISTRATION

The study had been approved by the Institutional Review Board of the hospital (2017 ethics No.43) and was registered under Clinicaltrials.gov with an identifier NCT02893722.

Endometrial HLA-F expression is influenced by genotypes and correlates differently with immune cell infiltration in IVF and recurrent implantation failure patients

STUDY QUESTION

Is human leukocyte antigen (HLA)-F protein expressed in mid-secretory endometrium, and are its expression levels influenced by HLA-F gene polymorphisms and correlated with the abundance of uterine natural killer (uNK) cells and anti-inflammatory M2 macrophages?

SUMMARY ANSWER

HLA-F protein is expressed in mid-secretory endometrium, and levels are correlated with immune cell infiltration, plasma progesterone concentrations and HLA-F single-nucleotide polymorphisms (SNPs), however, women experiencing recurrent implantation failure (RIF) show differences when compared to women attending their first IVF treatment.

WHAT IS KNOWN ALREADY

The immunomodulatory HLA class Ib molecules HLA-G and HLA-F are expressed on the extravillous trophoblast cells and interact with receptors on maternal immune cells. Little is known regarding HLA-F expression in endometrial stroma and HLA-F function; furthermore, HLA-F and HLA-G SNP genotypes and haplotypes have been correlated with differences in time-to-pregnancy.

STUDY DESIGN, SIZE, DURATION

Primary endometrial stromal cell (ESC) cultures (n = 5) were established from endometrial biopsies from women attending IVF treatment at a fertility clinic. Basic HLA-F and HLA-G protein expression by the ESCs were investigated. A prospective controlled cohort study was performed including 85 women with a history of RIF and 36 control women beginning their first fertility treatment and with no history of RIF. In some analyses, the RIF group was divided into unknown cause, male infertility, female infertility, and both female and male infertility. Endometrial biopsies and blood samples were obtained the day equivalent to embryo transfer in a hormone-substituted cycle.

PARTICIPANTS/MATERIALS, SETTING, METHODS

HLA protein expression by ESCs was characterized using flow cytometry and western blot. In the cohort study, the specific immune markers HLA-F and HLA-G, CD56 and CD16 (NK cells), CD163 (M2 macrophages), FOXP3 (regulatory T cells) and CD138 (plasma cells) were analysed by immunohistochemistry and a digital image analysis system in endometrial biopsies. Endometrial receptivity was assessed by an endometrial receptivity array test (the ERA® test). Endometrial biopsies were examined according to modified Noyes' criteria. SNPs at the HLA-F gene and HLA-G haplotypes were determined.

MAIN RESULTS AND THE ROLE OF CHANCE

HLA-F protein is expressed in the endometrium at the time of implantation. Furthermore, the HLA-F protein levels were different according to the womeńs HLA-F SNP genotypes and diplotypes, which have previously been correlated with differences in time-to-pregnancy. Endometrial HLA-F was positively correlated with anti-inflammatory CD163+ M2 macrophage infiltration and CD56+ uNK cell abundance for the entire cohort. However, this was not the case for CD56+ in the female infertility RIF subgroup. HLA-F levels in the endometrial stroma were negatively correlated with plasma progesterone concentrations in the RIF subgroup with known female infertility. Conversely, HLA-F and progesterone were positively correlated in the RIF subgroup with infertility of the male partner and no infertility diagnosis of the woman indicating interconnections between progesterone, HLA-F and immune cell infiltration. Glandular sHLA-G expression was also positively correlated with uNK cell abundance in the RIF subgroup with no female infertility but negatively correlated in the RIF subgroup with a female infertility diagnosis.

LARGE SCALE DATA

Immunohistochemistry analyses of endometrial biopsies and DNA sequencing of HLA genes. Data will be shared upon reasonable request to the corresponding author.

LIMITATIONS, REASONS FOR CAUTION

The control group of women attending their first IVF treatment had an anticipated good prognosis but was not proven fertile. A significant age difference between the RIF group and the IVF group reflects the longer treatment period for women with a history of RIF. The standardization of hormonal endometrial preparation, which allowed consistent timing of endometrial and blood sampling, might be a strength because a more uniform hormonal background may more clearly show an influence on the immune marker profile and HLA class Ib levels in the endometrium by other factors, for example genetic polymorphisms. However, the immune marker profile might be different during a normal cycle.

WIDER IMPLICATIONS OF THE FINDINGS

The findings further highlight the importance of HLA-F and HLA-G at the implantation site and in early pregnancy for pregnancy success. Diagnostic measures and modulation of the complex interactions between HLA class Ib molecules, maternal immune cells and hormonal factors may have potential to improve fertility treatment.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Region Zealand Health Sciences Research Foundation and the Zealand University Hospital through the ReproHealth Research Consortium ZUH. The authors declared there are no conflicts of interest.

The Role of Endometrial Stem/Progenitor Cells in Recurrent Reproductive Failure

Recurrent implantation failure (RIF) and recurrent pregnancy loss (RPL), collectively referred to as recurrent reproductive failure (RRF), are both challenging conditions with many unanswered questions relating to causes and management options. Both conditions are proposed to be related to an aberrant endometrial microenvironment, with different proposed aetiologies related to a restrictive or permissive endometrium for an invading embryo. The impressive regenerative capacity of the human endometrium has been well-established and has led to the isolation and characterisation of several subtypes of endometrial stem/progenitor cells (eSPCs). eSPCs are known to be involved in the pathogenesis of endometrium-related disorders (such as endometriosis) and have been proposed to be implicated in the pathogenesis of RRF. This review appraises the current knowledge of eSPCs, and their involvement in RRF, highlighting the considerable unknown aspects in this field, and providing avenues for future research to facilitate much-needed advances in the diagnosis and management of millions of women suffering with RRF.

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.

Intrauterine Perfusion of Autologous Platelet-Rich Plasma Before Frozen-Thawed Embryo Transfer Improves the Clinical Pregnancy Rate of Women With Recurrent Implantation Failure

Objective

To evaluate whether the intrauterine perfusion of platelet-rich plasma (PRP) before frozen-thawed embryo transfer (FET) improves the pregnancy outcomes of patients with repeated implantation failure (RIF).

Methods

This retrospective study included 288 infertile women with RIF after undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment from October 1, 2019, to January 1, 2021, at Qingdao Women and Children's Hospital. Patients were divided into two groups according to whether they received PRP intrauterine perfusion before embryo transfer in FET cycles. 138 women were in the PRP group, 150 women were in the control group. The primary outcome measure was live birth rates and the secondary outcome were clinical pregnancy, positive β hCG, miscarriage and implantation rates.

Results

No significant differences in baseline demographic and clinical characteristics were observed between the two groups. Overall, significantly more women in the PRP group than in the control group achieved a live birth rate (41 women; 29.71% vs. 27 women; 18%) and a clinical pregnancy (50 women; 36.23% vs. 37 women; 24.67%). The PRP group had a higher implantation rate and lower spontaneous miscarriage rate than the control group, but these differences were not statistically significant. No pregnancy outcome difference between two groups in PCOS patients with RIF.

Conclusion

Our results showed that intrauterine perfusion of PRP before embryo transfer in FET cycles can significantly increase the live birth and clinical pregnancy rates in patients with RIF.

Emerging trends and frontier research on recurrent implantation failure: a bibliometric analysis

Background

Recurrent implantation failure (RIF) has been recognized to be a major obstacle to the successful application of artificial reproduction technologies. In this study, the trends in RIF research were examined through a bibliometric analysis evaluating relevant literature quantitatively and qualitatively.

Methods

A total of 1,764 publications from 2000 to 2020 were downloaded from the Web of Science Core Collection (WoSCC). Relevant articles were searched using the term "recurrent implantation failure" and other synonyms of this term. Using Excel 2013, CiteSpace V, and VOSviewer 1.6.10 software, data extracted from the literature, including countries/regions, institutions, journals, keywords, and trends, were analyzed. Next, a clustered network was constructed based on 46,718 references cited by the 1,764 publications to determine the top 10 cocited articles.

Results

The annual number of publications on RIF progressively increased over time. The highest number of publications were from the United States. Analysis of the cocited reference cluster showed that "endometrial injury", "platelet-rich plasma", "chronic endometritis" and "extracellular vesicles" were the hotspots in RIF research. Burst detection analysis of the top keywords showed that "hysteroscopy" and "improvement" are emerging research foci.

Conclusions

This study clarifies the current research status and evolution of research in the field of RIF. New therapeutic interventions designed to improve pregnancy outcomes are the focus of current research and are expected to dominate future research in the field of RIF.

Metabolomic markers of biological fluid in women with reproductive failure: a systematic review of current literatures

Understanding metabolic changes in reproductive failure, including early miscarriage (EM), recurrent miscarriage (RM) and repeated implantation failure (RIF), may be beneficial to understand the pathophysiology, thus improving pregnancy outcomes. Nine metabolomic profiling studies in women with reproductive failures (4 for EM, 3 for RM and 2 for RIF) were included for systematic review. In total 78, 75 and 25 significant metabolites were identified and 40, 40 and 34 metabolic pathways were enriched in EM, RM and RIF, respectively. Among them, 7 and 11 metabolites, and 28 and 28 pathways were shared between EM and RM and between RM and RIF, respectively. Notably, histidine metabolism has the highest impact in EM; phenylalanine, tyrosine and tryptophan biosynthesis. Ubiquinone and other terpenoid-quinone biosynthesis metabolism have the highest impact factor in RM; alanine, aspartate and glutamate metabolism have the highest impact factor in RIF. This study not only summarized the common and distinct metabolites and metabolic pathways in different reproductive failures but also summarized limitations of the study designs and methodologies. Hence, further investigations and validations of these metabolites are still urgently needed to understand the underlying metabolic mechanism for the development and treatment of reproductive failures.

Clinical relevance of a newly developed endometrial receptivity test for patients with recurrent implantation failure in Japan

Purpose

To assess the clinical efficacy of personalized embryo transfer (pET) guided by a new endometrial receptivity test, ERPeak^SM, in patients with recurrent implantation failure (RIF).

Methods

Recurrent implantation failure patients of all ages at two private Japanese clinics from April 2019 to June 2020 were retrospectively analyzed. The intervention group (n = 244) received pET in accordance with endometrial receptivity testing results and was compared to control group (n = 306) receiving standardized timing, non‐personalized embryo transfer (npET). In propensity score matching analysis, the clinical pregnancy rate (CPR) and live birth rate (LBR) were compared between groups, and a subanalysis of advanced maternal age (AMA) (≥38 years old) versus non‐AMA (<38 years old) patients was also conducted.

Results

The CPR and LBR of the pET group were significantly higher than those of the npET group (37.7% vs. 20.0%, adjusted OR: 2.64; 95%CI, 1.70–4.11, p < 0.001 and 29.9% vs. 9.7%, adjusted OR: 4.13; 95%CI, 2.40–7.13, p < 0.001, respectively). Furthermore, in the subanalyses, the CPR and LBR of the pET group were significantly higher than those of the npET group in both the AMA non‐AMA patients.

Conclusions

The new ERPeak^SM endometrial receptivity test is a useful alternative diagnostic tool for poor‐prognosis patients, regardless of age.

Mouse Cre drivers: tools for studying disorders of the human female neuroendocrine-reproductive axis†

Benign disorders of the human female reproductive system, such primary ovarian insufficiency and polycystic ovary syndrome are associated with infertility and recurrent miscarriage, as well as increased risk of adverse health outcomes, including cardiovascular disease and type 2 diabetes. For many of these conditions, the contributing molecular and cellular processes are poorly understood. The overarching similarities between mice and humans have rendered mouse models irreplaceable in understanding normal physiology and elucidating pathological processes that underlie disorders of the female reproductive system. The utilization of Cre-LoxP recombination technology, which allows for spatial and temporal control of gene expression, has identified the role of numerous genes in development of the female reproductive system and in processes, such as ovulation and endometrial decidualization, that are required for the establishment and maintenance of pregnancy in mammals. In this comprehensive review, we provide a detailed overview of Cre drivers with activity in the neuroendocrine-reproductive axis that have been used to study disruptions in key intracellular signaling pathways. We first summarize normal development of the hypothalamus, pituitary, ovary, and uterus, highlighting similarities and differences between mice and humans. We then describe human conditions resulting from abnormal development and/or function of the organ. Finally, we describe loss-of-function models for each Cre driver that elegantly recapitulate some key features of the human condition and are associated with impaired fertility. The examples we provide illustrate use of each Cre driver as a tool for elucidating genetic and molecular underpinnings of reproductive dysfunction.

Human Chorionic Gonadotropin and Early Embryogenesis: Review

Human chorionic gonadotropin (hCG) has four major isoforms: classical hCG, hyperglycosylated hCG, free β subunit, and sulphated hCG. Classical hCG is the first molecule synthesized by the embryo. Its RNA is transcribed as early as the eight-cell stage and the blastocyst produces the protein before its implantation. This review synthetizes everything currently known on this multi-effect hormone: hCG levels, angiogenetic activity, immunological actions, and effects on miscarriages and thyroid function.

OUP accepted manuscript

STUDY QUESTION

Is the composition of microRNAs (miRNAs) in uterine fluid (UF) of women with recurrent implantation failure (RIF) different from that of healthy fertile women?

SUMMARY ANSWER

The composition of miRNAs in UF of women with RIF is different from that of healthy fertile women and the dysregulated miRNAs are associated with impaired endometrial receptivity and embryo implantation.

WHAT IS KNOWN ALREADY

It has previously been demonstrated that the miRNAs secreted from endometrial cells into the UF contribute to the achievement of endometrial receptivity. Endometrial miRNAs are dysregulated in women with RIF.

STUDY DESIGN, SIZE, DURATION

In this descriptive laboratory case–control study, miRNA abundancy was compared between UF collected during implantation phase from healthy fertile women (n = 17) and women with RIF (n = 34), which was defined as three failed IVF cycles with high-quality embryos.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Recruitment of study subjects and sampling of UF were performed at two university clinics in Stockholm, Sweden and Tartu, Estonia. The study participants monitored their menstrual cycles using an LH test kit. The UF samples were collected on Day LH + 7–9 by flushing with saline. Samples were processed for small RNA sequencing and mapped for miRNAs. The differential abundance of miRNAs in UF was compared between the two groups using differential expression analysis (DESeq2). Further downstream analyses, including miRNA target gene prediction (miRTarBase), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis (g:Profiler) and external validation using relevant published data, were performed on the dysregulated miRNAs. Two miRNAs were technically validated with quantitative real-time PCR (RT-PCR).

MAIN RESULTS AND THE ROLE OF CHANCE

After processing of the sequencing data, there were 15 samples in the healthy fertile group and 33 samples in the RIF group. We found 61 differentially abundant UF miRNAs (34 upregulated and 27 downregulated) in RIF compared to healthy women with a false discovery rate of <0.05 and a fold change (FC) of ≤−2 or ≥2. When analyzed with published literature, we found that several of the differentially abundant miRNAs are expressed in endometrial epithelial cells and have been reported in endometrial extracellular vesicles and in association with endometrial receptivity and RIF. Their predicted target genes were further expressed both in the trophectodermal cells of blastocyst-stage embryos and endometrial mid-secretory epithelial cells, as assessed by publicly available single-cell transcriptome-sequencing studies. Pathway analysis further revealed that 25 pathways, having key roles in endometrial receptivity and implantation, were significantly enriched. Hsa-miR-486-5p (FC −20.32; P-value = 0.004) and hsa-miR-92b-3p (FC −9.72; P-value = 0.004) were successfully technically validated with RT-PCR.

LARGE SCALE DATA

The data are available in Gene Expression Omnibus (GEO) at https://www.ncbi.nlm.nih.gov/geo/ with GEO accession number: GSE173289.

LIMITATIONS, REASONS FOR CAUTION

This is a descriptive study with a limited number of study participants. Moreover, the identified differentially abundant miRNAs should be validated in a larger study cohort, and the predicted miRNA target genes and enriched pathways in RIF need to be confirmed and further explored in vitro.

WIDER IMPLICATIONS OF THE FINDINGS

RIF is a major challenge in the current IVF setting with no diagnostic markers nor effective treatment options at hand. For the first time, total miRNAs have been extensively mapped in receptive phase UF of both healthy women with proven fertility and women diagnosed with RIF. Our observations shed further light on the molecular mechanisms behind RIF, with possible implications in future biomarker and clinical treatment studies.

STUDY FUNDING/COMPETING INTEREST(S)

This work was financially supported by the Swedish Research Council (2017-00932), a joint grant from Region Stockholm and Karolinska Institutet (ALF Medicine 2020, FoUI-954072), Estonian Research Council (PRG1076), Horizon 2020 innovation (ERIN, EU952516) and European Commission and Enterprise Estonia (EU48695). The authors have no competing interests to declare for the current study.

Intrauterine interventions for women with two or more implantation failures: A systematic review and network meta-analysis

OBJECTIVE

To compare the effectiveness of different intrauterine interventions for women with two or more unexplained implantation failures.

DESIGN

A systematic review and network meta-analysis of randomized controlled trials (RCTs).

PATIENTS

Women with two or more implantation failures undergoing fresh or frozen embryo transfer (ET).

INTERVENTIONS

An electronic search of the following databases: Pubmed, Cochrane Central Register of Controlled Trials (CENTRAL), and Embase.

MAIN OUTCOME MEASURES

Clinical pregnancy, live birth/ongoing pregnancy, and miscarriage.

RESULTS

We included 21 RCTs(3079 women) in the network meta-analysis. The network meta-analysis showed that compared with control treatment, platelet-rich plasma(PRP), peripheral blood mononuclear cells (PBMC), granulocyte colony-stimulating factor(G-CSF), human chorionic gonadotropin(HCG), and endometrial scratch(ES) significantly increased clinical pregnancy(OR 3.78, 95% CI 2.72 to 5.25; 2.79, 95% CI 1.75 to 4.45; 1.93, 95% CI 1.37 to 2.72; 1.80, 95% CI 1.18 to 2.72; 1.75, 95% CI 1.29 to 2.36, respectively). PRP ranked the highest in improving clinical pregnancy, followed by PBMC, G-CSF, HCG, and ES. Compared with control treatment, PRP, PBMC, and ES significantly increased live birth/ongoing pregnancy (OR 5.96, 95% CI 3.38 to 10.52; OR 2.55, 95% CI 1.27 to 5.11; OR 1.70, 95% CI 1.07 to 2.69, respectively). PRP ranked the highest in improving live birth/ongoing pregnancy, followed by PBMC, and ES.

CONCLUSIONS

PRP is the most effective intrauterine intervention in improving pregnancy outcome in women with two or more implantation failures.

Recurrent Implantation Failure May Be Identified by a Combination of Diagnostic Biomarkers: An Analysis of Peripheral Blood Lymphocyte Subsets

BACKGROUND

Recurrent implantation failure (RIF) is a challenge during assisted reproductive technology (ART). In the present study, potential diagnostic biomarkers for the immune status of peripheral blood lymphocyte subsets in patients with RIF were analyzed, with the aim of identifying novel biomarkers that may predict RIF.

METHODS

A total of 41 participants, including 21 women with RIF and 20 fertile controls, were included in the present study. Functional analysis was performed and the cytokine status of natural killer (NK), T, CD8+ T, T helper (Th), and γδ T cells which are lymphocyte subsets in peripheral blood was measured using flow cytometry. Binary logistic regression analysis adjusted for T follicular helper 1 (Tfh1), Tfh2, Tfh17, and early NK cells was performed to determine the relationship between the peripheral blood lymphocyte subsets and RIF. Potential diagnostic biomarkers were assessed by logistic regression analysis and receiver operating characteristic curves.

RESULTS

There were significantly more Tfh1, Tfh17, and NK cells in the RIF group compared with the control group (all P < 0.05). However, the percentage of T, regulatory T (Tregs), and Tfh2 cells, as well as early inhibitory NK cells, was significantly lower in the RIF group compared with the control group (all P < 0.05). Following logistics regression analysis, Treg, Tfh17, and early inhibitory NK cells exhibited significant differences between the two groups. Combination diagnosis using these 3 biomarkers had a higher area under the curve of 0.900 (95% confidence interval: 0.808-0.992, P < 0.001) in the RIF group compared with that in the control group.

CONCLUSION

T, Tregs, Tfh1, Tfh2, Tfh17, NK cells, and early inhibitory NK cells may play important regulatory roles in embryo implantation. The combination of 3 molecular markers (Treg, Tfh17, and early inhibitory NK cells) could provide a high diagnostic value for women with RIF, thus providing novel potential biomarkers for RIF in ART. The present findings could provide a reference either for the clinical treatment of patients with RIF or for future large, well-designed studies.

Novel microarchitecture of human endometrial glands: implications in endometrial regeneration and pathologies

BACKGROUND

Human endometrium remains a poorly understood tissue of the female reproductive tract. The superficial endometrial functionalis, the site of embryo implantation, is repeatedly shed with menstruation, and the stem cell-rich deeper basalis is postulated to be responsible for the regeneration of the functionalis. Two recent manuscripts have demonstrated the 3D architecture of endometrial glands. These manuscripts have challenged and replaced the prevailing concept that these glands end in blind pouches in the basalis layer that contain stem cells in crypts, as in the intestinal mucosa, providing a new paradigm for endometrial glandular anatomy. This necessitates re-evaluation of the available evidence on human endometrial regeneration in both health and disease in the context of this previously unknown endometrial glandular arrangement.

OBJECTIVE AND RATIONALE

The aim of this review is to determine if the recently discovered glandular arrangement provides plausible explanations for previously unanswered questions related to human endometrial biology. Specifically, it will focus on re-appraising the theories related to endometrial regeneration, location of stem/progenitor cells and endometrial pathologies in the context of this recently unravelled endometrial glandular organization.

SEARCH METHODS

An extensive literature search was conducted from inception to April 2021 using multiple databases, including PubMed/Web of Science/EMBASE/Scopus, to select studies using keywords applied to endometrial glandular anatomy and regeneration, and the references included in selected publications were also screened. All relevant publications were included.

OUTCOMES

The human endometrial glands have a unique and complex architecture; branched basalis glands proceed in a horizontal course adjacent to the myometrium, as opposed to the non-branching, vertically coiled functionalis glands, which run parallel to each other as is observed in intestinal crypts. This complex network of mycelium-like, interconnected basalis glands is demonstrated to contain endometrial epithelial stem cells giving rise to single, non-branching functionalis glands. Several previous studies that have tried to confirm the existence of epithelial stem cells have used methodologies that prevent sampling of the stem cell-rich basalis. More recent findings have provided insight into the efficient regeneration of the human endometrium, which is preferentially evolved in humans and menstruating upper-order primates.

WIDER IMPLICATIONS

The unique physiological organization of the human endometrial glandular element, its relevance to stem cell activity and scarless endometrial regeneration will inform reproductive biologists and clinicians to direct their future research to determine disease-specific alterations in glandular anatomy in a variety of endometrial pathological conditions.

Intrauterine administration of activated peripheral blood mononuclear cells in intrauterine insemination: a prospective double-blind randomized clinical trial

OBJECTIVE

To evaluate the effect of intrauterine administration of activated peripheral blood mononuclear cells (PBMC) on intrauterine insemination (IUI) success rates.

METHODS

This prospective double-blind randomized parallel clinical trial included 213 patients undergoing IUI at the Fertilys clinic. PBMC were isolated on the day of ovulation (day 0; D0) and stimulated with phytohemagglutinin (PHA) and human chorionic gonadotropin (hCG) for 48 hours (day 2; D2). Patients in the PBMC group (n = 108) underwent in utero administration of 1.10⁶ cells on D2, while patients in the control group (n = 105) were administered sperm-washing medium. Distribution of CD4 T lymphocyte populations (n = 61) was assessed on D0 and D2. Pregnancy and live birth rates were also evaluated.

RESULTS

Demographic and clinical characteristics, pregnancy rates, and live birth rates were not significantly different between the PBMC and control groups. Significantly higher levels of T helper (Th) 2, Th22, and T regulatory cells (P < 0.0001) and lower levels of Th17 cells were observed in hCG-activated PBMC at D2 than at D0.

CONCLUSION

Intrauterine administration of PBMC was not beneficial in IUI patients. New clinical approaches to better identify patients requiring endometrium immunomodulation needs to be addressed.

Associations between dyslipidaemia and pregnancy outcomes in the first complete cycle of IVF/ICSI: a real-world analysis

RESEARCH QUESTION

Are there associations between dyslipidaemia and pregnancy outcomes in the first complete cycle of IVF/intracytoplasmic sperm injection (ICSI)?

DESIGN

This long-term, retrospective real-world analysis involved 5030 infertile women who underwent a first complete IVF/ICSI cycle between January 2015 and October 2020. They were categorized into dyslipidaemia (n = 1903) and control (n = 3127) groups according to serum lipid concentrations before ovarian stimulation. Propensity score matching and multivariable logistic regression were used to control for confounding variables.

RESULTS

In the raw cohort, women with dyslipidaemia had a significantly increased late miscarriage rate (P = 0.039), decreased term birth rate (P = 0.002) and decreased live birth rate (P = 0.005) compared with non-dyslipidaemic women. In the propensity score-matched cohort, the term birth rate (P = 0.038) and live birth rate (P = 0.044) were significantly lower in the dyslipidaemia group (n = 1686) than the controls (n = 1686). Multivariable logistic regression indicated that infertile women with dyslipidaemia (P = 0.026) and elevated serum total cholesterol concentrations (total cholesterol ≥5.20 mmol/l; P = 0.028) were significantly less likely to have a live birth. Rates of late miscarriage (P = 0.027), term birth (P = 0.003) and live birth (P = 0.010) differed significantly among women with normal, borderline increased and increased serum lipid concentrations. Compared with controls, women with increased serum lipid concentrations had a significantly higher late miscarriage rate, lower term birth rate and lower live birth rate. Women with increased serum lipid concentrations were significantly less likely than controls to have a live birth.

CONCLUSIONS

Dyslipidaemia, total cholesterol ≥5.20 mmol/l and degrees of elevated serum lipid concentrations are negatively associated with live birth rate in the first complete IVF/ICSI cycle in infertile women.

Interaction Between Chronic Endometritis Caused Endometrial Microbiota Disorder and Endometrial Immune Environment Change in Recurrent Implantation Failure

Objective

To investigate the Interaction between chronic endometritis (CE) caused endometrial microbiota disorder and endometrial immune environment change in recurrent implantation failure (RIF).

Method

Transcriptome sequencing analysis of the endometrial of 112 patients was preform by using High-Throughput Sequencing. The endometrial microbiota of 43 patients was analyzed by using 16s rRNA sequencing technology.

Result

In host endometrium, CD4 T cell and macrophage exhibited significant differences abundance between CE and non-CE patients. The enrichment analysis indicated differentially expressed genes mainly enriched in immune-related functional terms. Phyllobacterium and Sphingomonas were significantly high infiltration in CE patients, and active in pathways related to carbohydrate metabolism and/or fat metabolism. The increased synthesis of lipopolysaccharide, an important immunomodulator, was the result of microbial disorders in the endometrium.

Conclusion

The composition of endometrial microorganisms in CE and non-CE patients were significantly different. Phyllobacterium and Sphingomonas mainly regulated immune cells by interfering with the process of carbohydrate metabolism and/or fat metabolism in the endometrium. CE endometrial microorganisms might regulate Th17 response and the ratio of Th1 to Th17 through lipopolysaccharide (LPS).

Differential expression of innate/adaptive immunity genes induced by endometrial scratching as a hopeful approach for implantation boosting in unexplained, repeated implantation failure: An RCT

BACKGROUND

Endometrial scratching (ES) has been proposed as a potential treatment for implantation improvement in unexplained repeated implantation failure (uRIF) patients, however, little is known about its exact molecular mechanisms.

OBJECTIVE

This randomized controlled trial (RCT) was conducted on twenty uRIF patients to investigate the expression of innate and adaptive immune signaling genes after ES.

METHODS

Ten uRIF patients in the intervention (twice endometrial sampling in follicular and luteal phases) and 10 uRIF patients in the control group (only luteal phase sampling) were randomly enrolled. Gene expression analysis with innate and adaptive immune response PCR-array kit between intervention and control groups were performed.

RESULTS

Among innate immune-associated genes, a significant decrease was observed in the expression of APCS, CPR, CCL2, NLRP3, HLA-A, TLR3 and TLR4 in the intervention group. In adaptive immune-related genes, the expression level of CD80, CD86, CXCR3, IFNγ, IFNα1, IFNβ, MBL2, CCR6, CCR8 and IL17A were decreased and CSF2, GATA3, and IL4 increased significantly in the intervention group (P < 0.05). Of 14 uRIF patients, five live birth (35.71 %) was achieved.

CONCLUSION

ES in uRIF patients may exert positive effects on the endometrial preparation which increases its receptivity for embryo implantation by modulating the expression of an array of immune signaling pathway genes.

The Role of Uterine Natural Killer Cells on Recurrent Miscarriage and Recurrent Implantation Failure: From Pathophysiology to Treatment

Uterine natural killer (uNK) cells constitute a unique uterine leucocyte subpopulation facilitating implantation and maintaining pregnancy. Herein, we critically analyze current evidence regarding the role of uNK cells in the events entailed in recurrent implantation failure (RIF) and recurrent miscarriages (RM). Data suggest an association between RIF and RM with abnormally elevated uNK cells’ numbers, as well as with a defective biological activity leading to cytotoxicity. However, other studies do not concur on these associations. Robust data suggesting a definitive causative relationship between uNK cells and RIF and RM is missing. Considering the possibility of uNK cells involvement on RIF and RM pathophysiology, possible treatments including glucocorticoids, intralipids, and intravenous immunoglobulin administration have been proposed towards addressing uNK related RIF and RM. When considering clinical routine practice, this study indicated that solid evidence is required to report on efficiency and safety of these treatments as there are recommendations that clearly advise against their employment. In conclusion, defining a causative relationship between uNK and RIF–RM pathologies certainly merits investigation. Future studies should serve as a prerequisite prior to proposing the use of uNK as a biomarker or prior to targeting uNK cells for therapeutic purposes addressing RIF and RM.

Efficacy of intralipid administration to improve in vitro fertilization outcomes: A systematic review and meta-analysis

We performed a systematic review and meta-analysis to evaluate whether intralipid administration improved the outcomes of in vitro fertilization. Online databases (PubMed, Cochrane Library, Medline, and Embase) were searched until March 2020. Only randomized controlled trials (RCTs) that assessed the role of intralipid administration during in vitro fertilization were considered. We analyzed the rates of clinical pregnancy and live birth as primary outcomes. Secondary outcomes included the rates of chemical pregnancy, ongoing pregnancy, and missed abortion. We reviewed and assessed the eligibility of 180 studies. Five RCTs including 840 patients (3 RCTs: women with repeated implantation failure, 1 RCT: women with recurrent spontaneous abortion, 1 RCT: women who had experienced implantation failure more than once) met the selection criteria. When compared with the control group, intralipid administration significantly improved the clinical pregnancy rate (risk ratio [RR], 1.48; 95% confidence interval [CI], 1.23-1.79), ongoing pregnancy rate (RR, 1.82; 95% CI, 1.31-2.53), and live birth rate (RR, 1.85; 95% CI, 1.44-2.38). However, intralipid administration had no beneficial effect on the miscarriage rate (RR, 0.75; 95% CI, 0.48-1.17). A funnel plot analysis revealed no publication bias. Our findings suggest that intralipid administration may benefit women undergoing in vitro fertilization, especially those who have experienced repeated implantation failure or recurrent spontaneous abortion. However, larger, well-designed studies are needed to confirm these findings.

circFAM120A participates in repeated implantation failure by regulating decidualization via the miR-29/ABHD5 axis

Repeated implantation failure (RIF) is a major problem that limits the pregnancy rate associated with assisted reproductive technology. However, the pathogenesis of RIF is still unknown. Recently, the expression levels of circular RNAs (circRNAs) were profiled in the endometrial tissues of patients with RIF. However, the exact role of circRNAs in RIF remains unclear. In our study, we found that circFAM120A levels were significantly down-regulated in the endometrium at the window of implantation in RIF patients compared with non-RIF controls. The suppression of circFAM120A expression inhibited decidualization in human endometrial stromal cells (hESCs). Furthermore, RNA-seq analysis after circFAM120A knockdown revealed ABHD5 as a potential downstream target gene of circFAM120A. As expected, down-regulating ABHD5 in hESCs also inhibited decidualization. Using the starBase and TargetScan databases, we predicted that miR-29 may interact with ABHD5, based on nucleotide sequence matching. Luciferase reporter assay showed that miR-29 bound to the 3' UTR of ABHD5 at the predicted complementary sites. Moreover, miR-29 mimics efficiently reduced ABHD5 expression levels and suppressed the decidualization process, whereas a miR-29 inhibitor partly rescued ABHD5 mRNA expression level and decidualization reduced by the knockdown of circFAM120A. Therefore, circFAM120A modulated decidualization in RIF through the miR-29/ABHD5 axis.

Transplantation of human umbilical cord mesenchymal stem cells to treat premature ovarian failure

As one of the problems and diseases for women before 40 years, premature ovarian failure (POF) could be characterized by amenorrhea, low estrogen levels, infertility, high gonadotropin levels, and lack of mature follicles. Causes of the disease involve some genetic disorders, autoimmunity diseases, and environmental factors. Various approaches have been employed to treat POF, however with limited success. Today, stem cells are used to treat POF, since they have the potential to self-repair and regenerate, and are effective in treating ovarian failure and infertility. As mesenchymal stem cell (MSC) could simultaneously activate several mechanisms, many researchers consider MSC transplantation to be the best and most effective approach in cell therapy. A good source for mesenchymal stem cells is human umbilical cord (HUCMSC). Animal models with cyclophosphamide are required for stem cell treatment and performance of HUCMSC transplantation. Stem cell therapy could indicate the levels of ovarian markers and follicle-stimulating hormone receptor. It also increases ovarian weight, plasma E2 levels, and the amount of standard follicles. Herein, the causes of POF, effective treatment strategies, and the effect of HUCMSC transplantation for the treatment of premature ovarian failure are reviewed. Many studies have been conducted in this field, and the results have shown that stem cell treatment is an effective approach to treat infertility.