Effect of Intrauterine Administration of Seminal Plasma for Patients with Recurrent Implantation Failure Before FET: Study Protocol for a Prospective Randomised Controlled Trial

Background: To assess the effect of intrauterine administration of seminal plasma for patients with recurrent implantation failure before frozen-thawed embryo transfer. Methods: Trial design: This is a parallel group, randomized (1:1 allocation ratio) controlled trial.Participants: All patients will be recruited from Chengdu Women’s and Children’s Central Hospital. Inclusion criteria: 1. Women after IVF/ICSI treatment in Chengdu Women’s and Children’s Central Hospital. 2.Infertile women with a history of recurrent implantation failure. 3.Infertile couples (both male and female) aged between 20 and 39 years;4. Couples who have at least 1 good quality embryos for transfer. 5. Males had negative in infectious disease test. 6. The males have semen. 7. Women who intend to undergo FET after IVF or ICSI or pre-implantation genetic testing for aneuploidy (PGT-A). 8. Competent and able to give informed consent. Intervention and comparator: Treatment group receiving intrauterine administration of seminal plasma before frozen-thawed embryo transfer. Main outcomes: Clinical pregnancy after frozen-thawed embryo transfer. Randomisation: Patients will be randomly allocated to either treatment or control group at 1:1 ratio. Random numbers will be generated by using software SPSS 25.0 performed by an independent statistician from Chengdu Women’s and Children’s Central Hospital. Blinding (masking): Only the data analyst will be blinded to group assignment. Numbers to be randomised (sample size): To account for a 10% dropout rate, we will recruit 174 patients (87 in each group). Trial status: The date of approval is 31rd May 2021, version 2.0. Recruitment started on 1rd June and is expected to end in July 2022. Discussion: Intrauterine administration of seminal plasma before frozen-thawed embryo transfer of patients with recurrent implantation failure may improve clinical pregnancy rate, it has great Page 2 of 14 significance for assisted reproduction. Trial registration: The study protocol has been approved by the ethics committees at Chengdu Women’s and Children’s Central Hospital. The trial was registered at the Chinese Clinical Trial Registry ChiCTR2100046803. Registered on 28 May 2021.

Recurrent Implantation Failure—Is It the Egg or the Chicken?

Recurrent implantation failure (RIF) is an undefined, quite often, clinical phenomenon that can result from the repeated failure of embryo transfers to obtain a viable pregnancy. Careful clinical evaluation prior to assisted reproduction can uncover various treatable causes, including endocrine dysfunction, fibroid(s), polyp(s), adhesions, uterine malformations. Despite the fact that it is often encountered and has a critical role in Assisted Reproductive Technique (ART) and human reproduction, RIF’s do not yet have an agreed-on definition, and its etiologic factors have not been entirely determined. ART is a complex treatment with a variable percentage of success among patients and care providers. ART depends on several factors that are not always known and probably not always the same. When confronted with repeated ART failure, medical care providers should try to determine whether the cause is an embryo or endometrium related. One of the most common causes of pregnancy failure is aneuploidy. Therefore, it is likely that this represents a common cause of RIF. Other RIF potential causes include immune and endometrial factors; however, with a very poorly defined role. Recent data indicate that the possible endometrial causes of RIF are very rare, thereby throwing into doubt all endometrial receptivity assays. All recent reports indicate that the true origin of RIF is probably due to the “egg”.

Increased METTL3-mediated m6A methylation inhibits embryo implantation by repressing HOXA10 expression in recurrent implantation failure

Background Recurrent implantation failure (RIF) is a major limitation of assisted reproductive technology, which is associated with impaired endometrial receptivity. Although N6-methyladenosine (m6A) has been demonstrated to be involved in various biological processes, its potential role in the endometrium of women with RIF has been poorly studied. Methods Global m6A levels and major m6A methyltransferases/demethylases mRNA levels in mid-secretory endometrium from normal and RIF women were examined by colorimetric m6A quantification strategy and quantitative real-time PCR, respectively. The effects of METTL3-mediated m6A modification on embryo attachment were evaluated by an vitro model of a confluent monolayer of Ishikawa cells co-cultured with BeWo spheroids, and the expression levels of homeo box A10 (HOXA10, a well-characterized marker of endometrial receptivity) and its downstream targets were evaluated by quantitative real-time PCR and Western blotting in METTL3-overexpressing Ishikawa cells. The molecular mechanism for METTL3 regulating HOXA10 expression was determined by methylated RNA immunoprecipitation assay and transcription inhibition assay. Results Global m6A methylation and METTL3 expression were significantly increased in the endometrial tissues from women with RIF compared with the controls. Overexpression of METTL3 in Ishikawa cells significantly decreased the ration of BeWo spheroid attachment, and inhibited HOXA10 expression with downstream decreased β3-integrin and increased empty spiracles homeobox 2 expression. METTL3 catalyzed the m6A methylation of HOXA10 mRNA and contributed to its decay with shortened half-life. Enforced expression of HOXA10 in Ishikawa cells effectively rescued the impairment of METTL3 on the embryo attachment in vitro. Conclusion Increased METTL3-mediated m6A modification represents an adverse impact on embryo implantation by inhibiting HOXA10 expression, contributing to the pathogenesis of RIF.

MicroRNA signatures in plasma and plasma exosome during window of implantation for implantation failure following in-vitro fertilization and embryo transfer

Background MicroRNAs (miRNAs) are small, non-coding RNAs that are dysregulated in many diseases and can act as biomarkers. Although well-studied in cancer, the role of miRNAs in embryo implantation is poorly understood. Approximately 70% of embryos fail to implant following in-vitro fertilization and embryo transfer, 10% of patients experienced recurrent implantation failure. However, there are no well-established biomarkers that can predict implantation failure. Our purpose is to investigate distinct miRNA profiles in plasma and plasma exosomes during the window of implantation between patients with failed implantation and successful implantation. Methods We select a nested case-control population of 12 patients with implantation failure or successfully clinical pregnancy using propensity score matching. RNA was extracted from plasma and plasma exosomes collected during the window of implantation (WOI). MicroRNA expression in all samples was quantified using microRNA sequencing. The intersection of differently expressed miRNAs in plasma and exosomes were further validated in the GEO dataset. Significantly altered microRNAs in both plasma and plasma exosomes were then subjected to target prediction and KEGG pathway enrichment analyses to search for key signaling pathways. WGCNA analysis was performed to identify hub miRNAs associated with implantation. Results 13 miRNAs were differentially expressed in both plasma and plasma exosomes in patients with implantation failure. Among them, miR-150-5p, miR-150-3p, miR-149-5p, and miR-146b-3p had consistent direction changes in endometrium of patients with recurrent implantation failure (RIF), miR-342-3p had consistent direction changes in blood samples of patients with RIF. Pathway enrichment analysis showed that the target genes of differentially expressed miRNAs are enriched in pathways related to embryo implantation. WGCNA analysis indicated that miR-150-5p, miR-150-3p, miR-146b-3p, and miR-342-3p are hub miRNAs. Conclusions Implantation failure is associated with distinct miRNA profiles in plasma and plasma exosomes during WOI.