Novel therapeutic targets to improve IVF outcomes in endometriosis patients: a review and future prospects

Peri-implantation treatment with TNF-α inhibitor for endometriosis and/or adenomyosis women undergoing frozen-thawed embryo transfer: A retrospective cohort study

PROBLEM

Endometriosis and adenomyosis have common pathogenesis and close relationship, with multi-factors involved in related infertility and IVF failure. They lead to anatomical changes, ovarian reserve reduction, endocrine abnormalities, altered endometrial receptivity and immunological dysfunction. Collective evidence indicate that abnormal function of immune cells and secretion of cytokines are closely related to reproductive outcomes among the women. Some studies showed that increased secretion of tumor necrosis factor alpha (TNF-α) led a key role in pro-inflammatory response in women with endometriosis/adenomyosis.TNF-a is embrryotoxic and receptivity impairing. Therefore, immunotherapy is a targeted therapeutic strategy apart from routine treatment. TNF-α inhibitors such as etanercept and adalimumab were shown to reduce the embryotoxic and anti-inflammatory effects to increase IVF pregnancy rates in recurrent implantation failure or endometrioma patient. However, there's no evidence about the use of adalimumab for patients with endometriosis and/or adenomyosis undergoing Frozen embryo transfer(FET).

METHOD OF STUDY

A retrospective analysis of 141 women with endometriosis and/or adenomyosis undergoing FET from January 2021 to Jun 2023 was conducted.They were 20-42 years old, with or without previous implantation failure. Endometriosis was diagnosed by laparoscopy during their infertility workup and adenomyosis was confirmed by vaginal ultrasound screening. GnRH agonist and hormone replacement treatment (HRT) or HRT were taken for endometrium preparation according to doctor's evaluation and preference. Before and after embryo transfer, 84 women were treated with Adalimumab and 57 patients were untreated. Implantation rate, clinical pregnancy rate, ongoing pregnancy rate and live birth rate were compared between the two groups.

RESULTS

The demographics and baseline characteristics between the two groups were comparable. Stage of embryo transferred and number of embryo transferred were comparable between the two groups (p = 0.227 and p = 0.204 separately). The regimen of endometrium preparation was similar too(p = 0.907). The implantation rate was significantly improved in study group (28.09 % vs 49.18 %, X2=9.515, P = 0.002). The clinical pregnancy rate was much lower in control group comparing with TNF-α inhibitor treatment group (42.11 % vs 60.71 %, X2=4.723, P = 0.029). There was no significant difference between the two groups as for ongoing pregnancy rate (38.60 % vs 52.38 %, X2=2.591, P = 0.107)and live birth rate (36.84 % vs 47.62 %, X2=1.606, P = 0.205). Following adjustment for age, BMI, number of prior failed transfer, stage of embryo transferred in a multiple logistic analysis, patients treated without TNF-α inhibitor had a significant lower CPR (ORadj 0.45, 95 %CI 0.22-0.92, p = 0.029) and a similar probability for OPR (ORadj 0.56, 95 %CI 0.28-1.12) and LBR (ORadj 0.62, 95 %CI 0.31-1.26) as compared with patients with TNF-α inhibitor treatment. However, an obvious trend of improvement of LBR was observed and it's clinical relevant for the patients.

CONCLUSION

In women with endometriosis and/or adenomyosis, peri-implantation treatment with TNF-α inhibitor increased implantation rate and clinical pregnancy rate significantly compared with control group in FET cycles. The ongoing pregnancy rate and live birth rate were not significant different, while the difference was clinical relevant.

Ectopic endometrial stromal cell-derived extracellular vesicles encapsulating microRNA-25-3p induce endometrial collagen I deposition impairing decidualization in endometriosis

Endometrial collagen I undergoes dynamic degradation and remodelling in response to endometrial stromal cell (ESC) decidualization and embryo implantation. However, excessive collagen I deposition in the endometrium during the implantation window may impair decidualization, causing embryo implantation failure in patients with endometriosis (EMS). We found that endometrial collagen I expression during the mid-secretory phase was increased in the EMS group of patients. Collagen I stimulation resulted in decreased expression of the decidualization markers prolactin and insulin-like growth factor binding protein-1 in ESCs, impeding ESC transformation to a decidual morphology and decreasing the blastocyst-like spheroid expansion area in vitro. Treatment with extracellular vesicles (EVs) derived from the ectopic ESCs of EMS patients (EMS-EVs) increased collagen I expression in vivo and in vitro and decreased the blastocyst-like spheroid expansion area. Furthermore, EV microRNA (miRNA) sequencing revealed that there were 40 upregulated and 77 downregulated miRNAs in EMS-EVs when compared to the EVs derived from ESCs in the endometrium of control patients (CTL-EVs), including increased expression of miR-25-3p that targets phosphatase and tensin homolog (PTEN). We also found that PTEN expression was decreased and p-Akt expression was increased in the endometrium of EMS patients and EMS-EV-treated ESCs. miR-25-3p transfected ESCs exhibited increased collagen I, decreased PTEN, and increased p-Akt. Additionally, an EV uptake study further showed that EMS-EVs were preferentially taken up by ESCs rather than by endometrial epithelial cells. These results suggest that EMS-EVs encapsulating miR-25-3p might be preferentially taken up by eutopic ESCs where they may induce endometrial collagen I deposition to impair ESC decidualization in EMS.

Oocyte cryopreservation for women with endometriosis: Justification, indications, and reproductive outcomes

Women with endometriosis often experience diminished ovarian reserve and a decreased number of oocytes retrieved. This reduction is exacerbated after surgery. Nevertheless, oocyte quality does not seem to be compromised in these patients. When embryos of good quality are obtained, in vitro fertilization outcomes are generally satisfactory. Oocyte cryopreservation may represent a fertility preservation option for women with planned and/or prior surgery, as it enables the collection of oocytes in advance. Given the diverse manifestations of endometriosis, which vary by type, age, and ovarian reserve, the decision to pursue oocyte cryopreservation should be weighed individually. Moreover, the potential benefits of this approach on future fertility must be carefully considered. Considering current guidelines, the most appropriate candidates for oocyte cryopreservation among women with endometriosis are: patients with bilateral endometriomas, typically larger than 3 cm; those with prior surgery for unilateral endometrioma who exhibit ipsilateral or contralateral recurrence; and those with unilateral endometrioma on a single ovary. However, the size criteria for endometrioma warrant further discussion. Conversely, oocyte cryopreservation is inadvisable for patients: with unilateral endometrioma smaller than 3 cm and good ovarian reserve; who have undergone surgery for bilateral endometriomas, regardless of recurrence; and who have diminished ovarian reserve. While consensus indicates that decisions regarding diminished ovarian reserve should be individualized, fertility preservation should often be considered for patients with serum anti-Müllerian hormone levels below 0.5 ng/mL. In such cases, a prolonged duration may be necessary to retrieve the desired 10 to 15 oocytes.

The role and potential treatment of macrophages in patients with infertility and endometriosis

Endometriosis is characterized as a macrophage-related ailment due to its strong link with immune dysfunction. Understanding the status of macrophage polarization in the context of endometriosis-related infertility is crucial for advancing diagnostic and therapeutic strategies. Our comprehensive review delves into the foundational understanding of macrophages and their profound influence on both endometriosis and infertility. Additionally, we illuminate the complex role of macrophages in infertility and endometriosis specifically. Finally, we focused on four critical dimensions: follicular fluid, the intraperitoneal environment, endometrial receptivity, and strategies for managing endometriosis. It is clear that throughout the progression of endometriosis, the diverse polarization states of macrophages play a pivotal role in the internal reproductive environment of infertile individuals grappling with this condition. Modulating macrophage polarization in the reproductive environment of endometriosis patients could address infertility challenges more effectively, offering a promising pathway for treating infertility associated with endometriosis.

Oocyte Quality in Women with Endometriosis

BACKGROUND

Endometriosis is a chronic gynecological condition that affects approximately 10% of women of reproductive age globally. It is associated with significant morbidity due to symptoms such as pelvic pain and infertility. Current knowledge suggests that endometriosis impacts oocyte quality, a critical factor for successful fertilization and pregnancy. Despite extensive research, the exact mechanisms remain unclear, and further updates are necessary to optimize treatment strategies.

OBJECTIVES

This review aims to summarize current evidence regarding the impact of endometriosis on oocyte quality and its subsequent effects on fertility outcomes, particularly in the context of in vitro fertilization (IVF).

METHODS

A comprehensive search was conducted in PubMed using the terms "endometriosis AND oocyte quality," "endometriosis AND infertility, and "endometriosis AND IVF." The review included studies published up to July 2024.

OUTCOME

The review findings indicate that endometriosis may be associated with decreased oocyte quality, characterized by impaired morphological features and molecular abnormalities. These defects potentially lead to lower fertilization rates, impaired embryo development, and reduced pregnancy outcomes. However, some studies suggest that with controlled factors such as age and ovarian reserve, IVF outcomes may be comparable to those without endometriosis.

CONCLUSIONS AND OUTLOOK

For clinicians and scientists working in medically assisted reproduction, understanding the impact of endometriosis on oocyte quality is crucial for improving fertility treatment outcomes. Advances in assisted reproductive technologies and personalized treatment approaches may mitigate these adverse effects. The potential for using artificial intelligence to assess oocyte quality presents a promising avenue for future research, as currently there is no direct and objective measure to assess this parameter.

Single-cell RNA sequencing revealed the roles of macromolecule epidermal growth factor receptor (EGFR) in the hybrid sterility of hermaphroditic Argopecten scallops

The macromolecule epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein that belongs to the protein kinase superfamily, which plays versatile functions in cell proliferation, development and fertility regulation. Almost all F1 hybrids obtained from the hermaphroditic bay scallops and Peruvian scallops exhibit infertility, and the genetic mechanism remains unclear. In this study, the comprehensive scRNA-seq was first conducted in the gonads of hybrid scallops, deducing the developmental sequence of germ cells and identifying the critical regulators in hybrid sterility: epidermal growth factor receptor. During the development from oogenesis phase germ cells to oocytes, the expression of the EGFR gene gradually decreased in sterile hybrids but increased in fertile hybrids. The significantly lower EGFR expression and ATP content, but higher ROS production rate was detected in the gonad of sterile hybrids than that in fertile hybrids, which might cause slow development of oocytes, stagnation of cell cycle, insufficient energy supply, high level of apoptosis and final sterility. Specific knock-down of EGFR gene led to decreased ATP content, increased ROS production rate, and inhibited oocyte maturation and gonadal development. These findings provide new insights into the roles of EGFR in hybrid infertility of bivalves and the healthy development of scallop breeding.

The density of the inner cell mass is a new indicator of the quality of a human blastocyst: a valid supplement to the Gardner scoring system

STUDY QUESTION

Can the density of the inner cell mass (ICM) be a new indicator of the quality of the human blastocyst?

SUMMARY ANSWER

The densification index (DI) developed in this study can quantify ICM density and provide positive guidance for ploidy, pregnancy, and live birth.

WHAT IS KNOWN ALREADY

In evaluating the quality of ICM, reproductive care clinics still use size indicators without further evaluation. The main disadvantage of this current method is that the evaluation of blastocyst ICM is relatively rough and cannot meet the needs of clinical embryologists, especially when multiple blastocysts have the same ICM score, which makes them difficult to evaluate further.

STUDY DESIGN, SIZE, DURATION

This observational study included data from 2272 blastocysts in 1991 frozen-thawed embryo transfer (FET) cycles between January 2018 to November 2021 and 1105 blastocysts in 430 preimplantation genetic testing cycles between January 2019 and February 2023.

PARTICIPANTS/MATERIALS, SETTING, METHODS

FET, ICSI, blastocyst culture, trophectoderm biopsy, time-lapse (TL) monitoring, and next-generation sequencing were performed. After preliminary sample size selection, the 11 focal plane images captured by the TL system were normalized and the spatial frequency was used to construct the DI of the ICM.

MAIN RESULTS AND THE ROLE OF CHANCE

This study successfully constructed a quantitative indicator DI that can reflect the degree of ICM density in terms of fusion and texture features. The higher the DI value, the better the density of the blastocyst ICM, and the higher the chances that the blastocyst was euploid (P < 0.001) and that pregnancy (P < 0.001) and live birth (P = 0.005) were reached. In blastocysts with ICM graded B and blastocysts graded 4BB, DI was also positively associated with ploidy, pregnancy, and live birth (P < 0.05). ROC analysis showed that combining the Gardner scoring system with DI can more effectively predict pregnancy and live births, when compared to using the Gardner scoring system alone.

LIMITATIONS, REASONS FOR CAUTION

Accurate calculation of the DI value places high demands on image quality, requiring manual selection of the clearest focal plane and exposure control. Images with the ICM not completely within the field of view cannot be used. The association between the density of ICM and chromosomal mosaicism was not evaluated. The associations between the density of ICM and different assisted reproductive technologies and different culture conditions in embryo laboratories were also not evaluated. Prospective studies are needed to further investigate the impact of ICM density on clinical outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

ICM density assessment is a new direction in blastocyst assessment. This study explores new ways of assessing blastocyst ICM density and develops quantitative indicators and a corresponding qualitative evaluation scheme for ICM density. The DI of the blastocyst ICM developed in this study is easy to calculate and requires only TL equipment and image processing, providing positive guidance for clinical outcomes. The qualitative evaluation scheme of ICM density can assist embryologists without TL equipment to manually evaluate ICM density. ICM density is a simple indicator that can be used in practice and is a good complement to the blastocyst scoring systems currently used in most centers.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Key Research & Development Program of China (2021YFC2700603). The authors report no financial or commercial conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Dynamic intrauterine crosstalk promotes porcine embryo implantation during early pregnancy

Dynamic crosstalk between the embryo and mother is crucial during implantation. Here, we comprehensively profile the single-cell transcriptome of pig peri-implantation embryos and corresponding maternal endometrium, identifying 4 different lineages in embryos and 13 cell types in the endometrium. Cell-specific gene expression characterizes 4 distinct trophectoderm subpopulations, showing development from undifferentiated trophectoderm to polar and mural trophectoderm. Dynamic expression of genes in different types of endometrial cells illustrates their molecular response to embryos during implantation. Then, we developed a novel tool, ExtraCellTalk, generating an overall dynamic map of maternal-foetal crosstalk using uterine luminal proteins as bridges. Through cross-species comparisons, we identified a conserved RBP4/STRA6 pathway in which embryonic-derived RBP4 could target the STRA6 receptor on stromal cells to regulate the interaction with other endometrial cells. These results provide insight into the maternal-foetal crosstalk during embryo implantation and represent a valuable resource for further studies to improve embryo implantation.

Fertility preservation in women with endometriosis: Oocyte cryopreservation and other techniques

In recent years, advancements in cryopreservation techniques for oocytes, embryos, and ovarian tissue have enabled offering fertility preservation (FP) options to women with endometriosis. It is recommended to always conduct specialized counselling on FP, especially before considering surgical interventions for endometriosis. The decision regarding the methods of FP, the timing, and to which women affected by endometriosis these techniques should be offered are still subjects of discussion. However, several studies suggest that it can be proposed before surgical interventions for endometriosis, particularly if the patient is undergoing mono or bilateral endometrioma surgery. The most recommended technique is ovarian stimulation, followed by oocyte cryopreservation. Nevertheless, the literature contains various studies describing FP through embryo cryopreservation or the retrieval and cryopreservation of ovarian tissue.

Long noncoding RNA BMPR1B-AS1 stability regulated by IGF2BP2 affects the decidualization in endometriosis patients through the SMAD1/5/9 pathway

Endometriosis (EMs)-related infertility commonly has decreased endometrial receptivity and normal decidualization is the basis for establishing and maintaining endometrial receptivity. However, the potential molecular regulatory mechanisms of impaired endometrial decidualization in patients with EMs have not been fully clarified. We confirmed the existence of reduced endometrial receptivity in patients with EMs by scanning electron microscopy and quantitative real-time PCR. Here we identified an lncRNA, named BMPR1B-AS1, which is significantly downregulated in eutopic endometrium in EMs patients and plays an essential role in decidual formation. Furthermore, RNA pull-down, mass spectrometry, RNA immunoprecipitation, and rescue analyses revealed that BMPR1B-AS1 positively regulates decidual formation through interaction with the RNA-binding protein insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2). Downregulation of IGF2BP2 led to a decreased stability of BMPR1B-AS1 and inhibition of activation of the SMAD1/5/9 pathway, an inhibitory effect which diminished decidualization in human endometrial stromal cells (hESCs) decidualization. In conclusion, our identified a novel regulatory mechanism in which the IGF2BP2-BMPR1B-AS1-SMAD1/5/9 axis plays a key role in the regulation of decidualization, providing insights into the potential link between abnormal decidualization and infertility in patients with EMs, which will be of clinical significance for the management and treatment of infertility in patients with EMs.

Methyl 3,4-dihydroxybenzoate alleviates oxidative damage in granulosa cells by activating Nrf2 antioxidant pathway

Oxidative damage induced granulosa cells (GCs) apoptosis was considered as a significant cause of compromised follicle quality, antioxidants therapy has emerged as a potential method for improving endometriosis pregnancy outcomes. Here, we found that GCs from endometriosis patients show increased oxidative stress level. Methyl 3,4-dihydroxybenzoate (MDHB), a small molecule compound that is extracted from natural plants, reversed tert-butyl hydroperoxide (TBHP) induced GCs oxidative damage. Therefore, the aim of this study was to assess the protective effect of MDHB for GCs and its potential mechanisms. TUNEL staining and immunoblotting of cleaved caspase-3/7/9 showed MDHB attenuated TBHP induced GCs apoptosis. Mechanistically, MDHB treatment decreased cellular and mitochondria ROS production, improved the mitochondrial function by rescuing the mitochondrial membrane potential (MMP) and ATP production. Meanwhile, MDHB protein upregulated the expression of vital antioxidant transcriptional factor Nrf2 and antioxidant enzymes SOD1, NQO1 and GCLC to inhibited oxidative stress state, further beneficial to oocytes and embryos quality. Therefore, MDHB may represent a potential drug candidate in protecting granulosa cells in endometriosis, which can improve pregnancy outcomes for endometriosis-associated infertility.

Reproductive outcomes of single frozen-thawed embryo transfer in patients with endometriosis after preimplantation genetic testing

PURPOSE

The reproductive outcomes of patients with endometriosis who are infertile have attracted recent attention. We aimed to explore whether endometriosis affects endometrial receptivity by observing pregnancy outcomes following a euploid blastocyst frozen embryo transfer.

METHODS

This retrospective cohort study analyzed the data of patients with endometriosis from the reproductive hospital affiliated to Shandong University between January 2015 and December 2021. Control groups were matched using the 1:3 propensity score. The live birth, clinical pregnancy, biochemical pregnancy, clinical abortion, premature birth, and aneuploid rates were compared between the control group and endometriosis group.

RESULTS

A total of 625 patients who underwent preimplantation genetic testing (PGT) prior to embryo implantation were included in the analysis. There were no significant differences in the live birth, clinical pregnancy, biochemical pregnancy, clinical abortion, and premature birth rates between the two groups. The aneuploidy rate of blastocysts obtained from the endometriosis group was higher than that of the control group (P = 0.012).

CONCLUSION

Pregnancy outcomes using frozen embryos after PGT in patients with endometriosis did not differ from those in other women experiencing infertility. However, endometriosis may affect the quality of oocytes, resulting in a higher rate of aneuploidy.

IVF stimulation protocols and outcomes in women with endometriosis

Endometriosis is a complex medical condition with a high prevalence in women of reproductive age. Fertility is compromised in patients with endometriosis, and success in IVF treatments has been a challenge leading to evaluation of different stimulation protocols. The long-standing debate between GnRH agonist long protocols and short GnRH antagonist protocols is being resolved in favor of the latter, since in addition to presenting equivalent results with respect to the traditional option, they have the additional benefit of safety. The good results derived from vitrification techniques have led to the development of new stimulation strategies, such as progestin-primed ovarian stimulation (PPOS), with a greater degree of approval among patients. None of the stimulation protocols currently applied in women with endometriosis has been shown to be superior, so early intervention with an Assisted Reproduction treatment, regardless of the chosen protocol, can provide these women with good chances of motherhood. Women with endometrioma should be counseled for fertility preservation before planned ovarian endometrioma excision. The number of cryopreserved oocytes or embryos can be increased by repeated cycles.

What is the impact of endometriosis and the AFS stage on cumulative pregnancy rates in IVF programs?

BACKGROUND

Endometriosis is commonly observed in infertile women and can be staged with regard to severity [e.g. according to the American Fertility Society (AFS) classification]. This condition can cause infertility through impaired oocyte quality, fertilization disorders, tubal lesions, adhesions, deep infiltration, and adenomyosis. Although women with endometriosis often turn to in vitro fertilization (IVF) programs, the literature data on IVF outcomes are sometimes contradictory (i.e. the same as in other etiologies of infertility, or worse). The objective of the present study was to assess and compare pregnancy rates in women with and without endometriosis and according to the endometriosis stage.

METHODS

We retrospectively studied clinical and ongoing pregnancy rates in IVF and the cumulative pregnancy rates after frozen/thawed embryo transfers, in women without endometriosis (group A) or with endometriosis (group B). We further compared groups in which endometriosis was staged according to the revised AFS classification: stage 1/2 (group C), stage 3/4 (group D, without endometrioma), and endometrioma alone (group E).

RESULTS

We documented 430 cycles in group A and 460 in group B (including 56 in group C, 88 in group D and 316 in group E). After fresh or frozen/thawed embryo transfers, the differences in ongoing pregnancy rates between groups A and B were not significant. However the cumulative rates per couple were significantly lower (p < 0.05) in group D.

CONCLUSIONS

We recommend IVF for women with endometriosis because the pregnancy rates are similar to those observed for women with other types of infertility. This approach is in line with the international guidelines issued by assisted reproductive technology societies. These results again raise the question of whether surgical resection of deep infiltrating endometriosis (stage 3/4) should be recommended before admission to an IVF program. Trial registration This study was approved by an institutional review board (CPP Ouest VI, Brest, France): reference: B2020CE.43.

Regulated Cell Death in Endometriosis

Regulated cell death (RCD) represents a distinct mode of cell demise, differing from accidental cell death (ACD), characterized by specific signaling cascades orchestrated by diverse biomolecules. The regular process of cell death plays a crucial role in upholding internal homeostasis, acting as a safeguard against biological or chemical damage. Nonetheless, specific programmed cell deaths have the potential to activate an immune-inflammatory response, potentially contributing to diseases by enlisting immune cells and releasing pro-inflammatory factors. Endometriosis, a prevalent gynecological ailment, remains incompletely understood despite substantial progress in unraveling associated signaling pathways. Its complexity is intricately tied to the dysregulation of inflammatory immune responses, with various RCD processes such as apoptosis, autophagic cell death, pyroptosis, and ferroptosis implicated in its development. Notably, limited research explores the association between endometriosis and specific RCD pathways like pyroptosis and cuproptosis. The exploration of regulated cell death in the context of endometriosis holds tremendous potential for further advancements. This article thoroughly reviews the molecular mechanisms governed by regulated cell death and their implications for endometriosis. A comprehensive understanding of the regulated cell death mechanism in endometriosis has the potential to catalyze the development of promising therapeutic strategies and chart the course for future research directions in the field.

Injectable collagen hydrogel combines human umbilical cord mesenchymal stem cells to promote endometrial regeneration in rats with thin endometrium

The regeneration of thin endometrium still remains as a great challenge in the field of reproductive medicine. Stem cells-based therapy has been considered as a promising strategy for the restoration of thin endometrium. However, the low transplantation and retention rate of stem cells and loss of stemness due to in vitro expansion limits the therapeutic efficacy. In our study, we combined collagen hydrogel and human umbilical cord mesenchymal stem cells (uMSCs) for improving the regeneration of thin endometrium, by using the potent pluripotency and low immunogenicity of uMSCs and collagen hydrogel that promotes the anchorage and proliferation of stem cells. Results showed that collagen hydrogel has favorable biocompatibility and the capacity to enhance the cell viability and expression of stemness-associated genes (including organic cation/carnitine transporter4 (Oct-4), Nanog homeobox (Nanog) and SRY-box transcription factor 2 (SOX2)) of uMSCs. The combination of collagen hydrogel and uMSCs prolonged the retention time of the constructs in the uterine cavity and improved endometrial thickness compared with uMSCs alone, leading to increase the fertility of the rats with thin endometrium. These highlighted therapeutic prospects of collagen hydrogel combined with uMSCs for the minimally invasive therapy of thin endometrium in the clinic.

Chronic low-grade inflammation and ovarian dysfunction in women with polycystic ovarian syndrome, endometriosis, and aging

The ovarian microenvironment is critical for follicular development and oocyte maturation. Maternal conditions, including polycystic ovary syndrome (PCOS), endometriosis, and aging, may compromise the ovarian microenvironment, follicular development, and oocyte quality. Chronic low-grade inflammation can induce oxidative stress and tissue fibrosis in the ovary. In PCOS, endometriosis, and aging, pro-inflammatory cytokine levels are often elevated in follicular fluids. In women with obesity and PCOS, hyperandrogenemia and insulin resistance induce ovarian chronic low-grade inflammation, thereby disrupting follicular development by increasing oxidative stress. In endometriosis, ovarian endometrioma-derived iron overload can induce chronic inflammation and oxidative stress, leading to ovarian ferroptosis and fibrosis. In inflammatory aging (inflammaging), senescent cells may secrete senescence-associated secretory phenotype factors, causing chronic inflammation and oxidative stress in the ovary. Therefore, controlling chronic low-grade inflammation and fibrosis in the ovary would present a novel therapeutic strategy for improving the follicular microenvironment and minimizing ovarian dysfunction.

25(OH)D3 improves granulosa cell proliferation and IVF pregnancy outcomes in patients with endometriosis by increasing G2M+S phase cells

BACKGROUND

The 25-hydroxyvitamin D3 (25 (OH) D3) is crucial for follicular development. This study aimed to investigate the relationship between the level of 25 (OH) D3 in endometriosis patients, pregnancy outcomes of in vitro fertilization (IVF), and the underlying mechanism.

METHODS

The 25 (OH) D3 levels in serum and follicular Fluid (FF) samples were detected using enzyme-linked immunosorbent assay (ELISA). Clinical features and pregnancy outcomes of endometriosis patients were also compared between the deficient group (< 20 ug/ml) and the adequate group (≥ 20 ug/ml). The effects of 25 (OH) D3 on the proliferation and cell cycle of human ovarian granulosa cells were respectively detected by CCK-8 assay and flow cytometry (FCM). The differentially expressed genes (DEGs) in granulosa cells of endometriosis and tubal infertility patients were screened from GEO database. The effects of 25 (OH) D3 on the expressions of CDKN2D, PPARA, TGFB2 and THBD were determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot.

RESULTS

The levels of 25 (OH) D3 in serum and FF samples were decreased in endometriosis patients. The deficient group had fewer embryos that can be transferred, lower quality embryos and lower clinical pregnancy rates. Adequate 25 (OH) D3 levels in FF samples was a protective factor for live birth outcome in endometriosis patients. 25 (OH) D3 enhanced the proliferation capacity of granulosa cells (the concentration of 10 nM was the most significant) and increased the proportion of G2M + S phase cells. The expression of CDKN2D was decreased and TGFB2 and THBD were significantly upregulated.

CONCLUSIONS

25 (OH) D3 deficiency may be associated with poor IVF pregnancy outcomes in endometriosis patients. 25 (OH) D3 promotes ovarian granulosa cell proliferation by promoting the ability of cells to divide, and may accelerate cell cycle progression by up-regulating THBD and down-regulating CDKN2D expression.

Down-regulation of the FTO gene in follicular fluid of infertile women with ovarian endometriosis

OBJECTIVE

To evaluate FTO concentrations in follicular fluid (FF) of women with ovarian endometriosis (OE) and controls women without OE undergoing in vitro fertilization-embryo transfer (IVF-ET).

METHODS

FTO concentrations in FF were measured in 74 patients (37 in the control group and 37 in the OE group) by ELISA. We measured the expression of FTO in GCs of 40 patients (19 in the control group and 21 in the OE group) by RT-qPCR. The level of m6A in GCs was measured in 20 patients (10 in the control group and 10 in the OE group) by colorimetry.

RESULTS

Compared with the control group, FTO concentrations in FF (6.92 ± 0.44 vs. 5.67 ± 0.40 ng/ml) (p <.05) and FTO mRNA level in GCs of OE group were decreased significantly (p <.05), and the level of m6A was increased (0.21 ± 0.01 vs. 0.17 ± 0.03 ng) (p >.05).

CONCLUSIONS

The FTO concentrations in FF of infertility women with OE are decreased, which may be related to the impaired oocyte quality in endometriosis patients.

Decreased oocyte quality in patients with endometriosis is closely related to abnormal granulosa cells

Infertility and menstrual abnormalities in endometriosis patients are frequently caused by aberrant follicular growth or a reduced ovarian reserve. Endometriosis typically does not directly harm the oocyte, but rather inhibits the function of granulosa cells, resulting in a decrease in oocyte quality. Granulosa cells, as oocyte nanny cells, can regulate meiosis, provide the most basic resources required for oocyte development, and influence ovulation. Endometriosis affects oocyte development and quality by causing granulosa cells apoptosis, inflammation, oxidative stress, steroid synthesis obstacle, and aberrant mitochondrial energy metabolism. These aberrant states frequently interact with one another, however there is currently relatively little research in this field to understand the mechanism of linkage between abnormal states.

Presence of endometrioma decreased blastocyst formation rate but not impair Assisted Reproductive Technology (ART) outcome

PURPOSE

This study aims to assess the impact of endometrioma on patients who undergo ART treatment due to endometriosis.

METHODS

A retrospective study was conducted on women ≤ 40 years of age who underwent ART treatment at an academic medical center between January 2014 and December 2020. Two-hundred-and-eight women had received IVF/ICSI treatment due to endometriosis and there were 89 patients presence of endometrioma. Patients were further divided into primary endometrioma, recurrent endometrioma and those having received cystectomy for endometrioma prior to IVF/ICSI. The control group included 624 infertile women without endometriosis.

RESULTS

In the endometrioma subgroup (B) the blastocyst formation rate was significantly lower when compared with the endometriosis (A) and control groups (C). The cumulative live birth rates (CLBRs) (60.5% versus 49.4% versus 56.9%, p = 0.194 in A versus B, p = 0.406 in A versus C, p = 0.878 in B versus C) were comparable. Multiple logistic regression analysis revealed that female age, total FSH dose and blastocyst formation rate were the significant variables in predicting CLBR (OR 0.89, CI 0.80-0.99, p < 0.025, OR 0.68 CI 0.53-0.88, p = 0.003 and OR 30.04, CI 9.93-90.9, p < 0.001, respectively). The CLBRs were comparable at 47.1%, 60% and 57.9% in the primary endometrioma, s/p cystectomy and recurrent endometrioma group.

CONCLUSION

Although the blastocyst formation rate was lower in the endometrioma group, CLBR was not worse than those who were in the endometriosis or control group. Cystectomy for endometrioma did not alter IVF/ICSI outcomes if the ovarian reserve was comparable. Recurrent endometrioma did not worsen IVF/ICSI outcomes than primary endometrioma.

The Impact of Endometrioma on Embryo Quality in In Vitro Fertilization: A Retrospective Cohort Study

The influence of endometrioma on oocyte and embryo competence is inconclusive. Furthermore, the benefits of surgical treatment remain uncertain. This study aimed to investigate the effect of endometrioma on oocyte and embryo quality from a morphological perspective and further explore whether surgery could contribute to improving oocyte and embryo competence. A total of 664 IVF cycles with endometrioma (538 cycles underwent surgeries) and 3133 IVF cycles from the control group were included. The propensity score matching was used to balance the baseline differences between groups. There was a lower MII oocyte rate (85.0% versus 87.8%, p < 0.001; 84.9% versus 87.6%, p = 0.001) and a similar good-quality embryos rate in women with endometrioma (and those who underwent surgeries) compared with control group. For women with endometrioma, the rates of blastocyst development (67.1% versus 60.2%; p = 0.013) and good blastocyst development (40.7% versus 35.2%; p = 0.049) were significantly higher in those who had undergone surgical treatment compared with those who had not, but the rates of MII oocytes (79.9% versus 87.7%; p < 0.001) and normal fertilization (55.2% versus 66.2%; p < 0.001) were lower. The study indicates that endometrioma, including its surgical treatment, compromises the oocyte maturity not the embryo quality at the cleavage stage; however, the surgery seems to contribute to improving blastocyst development.

Reactive oxygen species and ovarian diseases: Antioxidant strategies

Reactive oxygen species (ROS) are mainly produced in mitochondria and are involved in various physiological activities of the ovary through signaling and are critical for regulating the ovarian cycle. Notably, the imbalance between ROS generation and the antioxidant defense system contributes to the development of ovarian diseases. These contradictory effects have critical implications for potential antioxidant strategies that aim to scavenge excessive ROS. However, much remains to be learned about how ROS causes various ovarian diseases to the application of antioxidant therapy for ovarian diseases. Here, we review the mechanisms of ROS generation and maintenance of homeostasis in the ovary and its associated physiological effects. Additionally, we have highlighted the pathological mechanisms of ROS in ovarian diseases and potential antioxidant strategies for treatment.

Impact of endometriosis on embryo quality and endometrial receptivity in women undergoing assisted reproductive technology

ART is an important treatment method for infertile patients with endometriosis. However, the effects of endometriosis on embryo quality and endometrial receptivity remain unclear. Thus, we aimed to simultaneously investigate the impact of endometriosis and its stage on embryo quality and endometrial receptivity in women undergoing ART. We retrospectively analyzed the data from patients with and without endometriosis who underwent oocyte retrieval and/or high-quality embryos transfer between July 2015 and December 2020, including 1312 IVF cycles and 608 IVF or frozen-thawed embryo transfer (FET) cycles, respectively. The endometriosis group had a lower percentage of good cleavage-stage embryos and fertilization rates than those in the control group (p = 0.038 and 0.008, respectively). The number of retrieved oocytes, MII oocytes, cleavage, blastocysts, and blastulation rates was comparable between two groups. We found no significant difference in clinical pregnancy, implantation, live birth, miscarriage, or multiple pregnancy rates between the two groups among patients who transferred high-quality embryos. Stratification analysis showed that patients with stage III-IV endometriosis had fewer retrieved oocytes than those with stage I-II endometriosis (p = 0.012) and marginally fewer retrieved oocytes than the control group (p = 0.051). The stage I-II group had the lowest percentage of good cleavage-stage embryos, which was significantly lower than that of the control group (p = 0.043). In FET cycles, patients with stage III-IV endometriosis had a higher miscarriage rate than those in the control group (p = 0.023). Our results suggest that endometriosis does not alter endometrial receptivity but affects embryo quality, oocyte fertilization ability, and ovarian response.

Is the long-acting gonadotropin-releasing hormone agonist long protocol better for patients with endometriosis undergoing IVF?

OBJECTIVE

To investigate the effect of the long-acting gonadotropin-releasing hormone agonist (GnRHa) long protocol on in vitro fertilization (IVF) outcomes of patients with endometriosis (EMs).

METHODS

This retrospective cohort study was carried out from July 1, 2016 to June 30, 2021. In all, 798 patients with EMs who underwent first IVF were enrolled. The patients were classified by the ovarian stimulation protocols. The clinical outcomes of IVF were compared in each group.

RESULTS

Those EMs patients who received the long-acting GnRHa long protocol had significantly higher clinical pregnancy rate (72.00%, 60.70% and 50.90%, respectively; P = 0.047 and 0.010) and implantation rate (51.0%, 44.6%, and 38.7%, respectively; P = 0.006 and <0.001) compared with the short-acting GnRHa long protocol and the GnRH antagonist protocol. Live birth rate was also significantly higher than the GnRH antagonist protocol (60.10% vs. 40.0%, P = 0.032), but not statistically different from the short-acting GnRHa (60.10% vs. 53.80%, P = 0.443). In addition, they also had significantly higher duration of stimulation, total dose of gonadotropin, and number of high-quality embryos transferred compared with other groups (P < 0.001).

CONCLUSIONS

The long-acting GnRHa long protocol could improve IVF outcomes of patients with EMs compared with the short-acting GnRHa long protocol and the GnRH antagonist protocol.

An injectable gelatin/sericin hydrogel loaded with human umbilical cord mesenchymal stem cells for the treatment of uterine injury

Abnormal endometrial receptivity is a major cause of the failure of embryo transplantation, which may lead to infertility, adverse pregnancy, and neonatal outcomes. While hormonal treatment has dramatically improved the fertility outcomes in women with endometriosis, a substantial unmet need persists in the treatment. In this study, methacrylate gelatin (GelMA) and methacrylate sericin (SerMA) hydrogel with human umbilical cord mesenchymal stem cells (HUMSC) encapsulation was designed for facilitating endometrial regeneration and fertility restoration through in situ injection. The presented GelMA/10%SerMA hydrogel showed appropriate swelling ratio, good mechanical properties, and degradation stability. In vitro cell experiments showed that the prepared hydrogels had excellent biocompatibility and cell encapsulation ability of HUMSC. Further in vivo experiments demonstrated that GelMA/SerMA@HUMSC hydrogel could increase the thickness of endometrium and improve the endometrial interstitial fibrosis. Moreover, regenerated endometrial tissue was more receptive to transfer embryos. Summary, we believed that GelMA/SerMA@HUMSC hydrogel will hold tremendous promise to repair or regenerate damaged endometrium.

Endometriosis-associated infertility: From pathophysiology to tailored treatment

Despite the clinically recognized association between endometriosis and infertility, the mechanisms implicated in endometriosis-associated infertility are not fully understood. Endometriosis is a multifactorial and systemic disease that has pleiotropic direct and indirect effects on reproduction. A complex interaction between endometriosis subtype, pain, inflammation, altered pelvic anatomy, adhesions, disrupted ovarian reserve/function, and compromised endometrial receptivity as well as systemic effects of the disease define endometriosis-associated infertility. The population of infertile women with endometriosis is heterogeneous, and diverse patients' phenotypes can be observed in the clinical setting, thus making difficult to establish a precise diagnosis and a single mechanism of endometriosis related infertility. Moreover, clinical management of infertility associated with endometriosis can be challenging due to this heterogeneity. Innovative non-invasive diagnostic tools are on the horizon that may allow us to target the specific dysfunctional alteration in the reproduction process. Currently the treatment should be individualized according to the clinical situation and to the suspected level of impairment. Here we review the etiology of endometriosis related infertility as well as current treatment options, including the roles of surgery and assisted reproductive technologies.

Implantation Failure in Endometriosis Patients: Etiopathogenesis

Embryo implantation requires adequate dialogue between a good quality embryo and a receptive endometrium. This implantation is still considered as the black box of reproductive medicine. Endometriosis is a highly prevalent chronic inflammatory disease, concerning about 10% of women of reproductive age and is one of the major causes of female infertility. The mechanisms involved in endometriosis-related infertility, an event not yet completely understood, are multifactorial and include anatomical changes, reduction in ovarian reserve, endocrine abnormalities, genetic profile, immunity markers, inflammatory mediators, or altered endometrial receptivity. In this article, we will focus on the impact of endometriosis on embryo quality and on endometrial receptivity. Results: Poor oocyte and embryo quality seem to promote a lower pregnancy rate, more than the endometrium itself in women with endometriosis. Other studies report the contrary. In addition, hormonal imbalance observed in the endometrium could also alter the embryo implantation. Conclusions: Controversial results in the literature add difficulties to the understanding of the mechanisms that lead to embryo implantation disorders. Furthermore, either oocyte/embryo impairment, altered endometrium, or both may cause impaired implantation. New prospective, randomized, and controlled studies are necessary to determine the origin of the defects that make conception more difficult in the case of endometriosis and adenomyosis.

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.

Incidence, dynamics and recurrences of reverse cleavage in aneuploid, mosaic and euploid blastocysts, and its relationship with embryo quality

Background

During embryonic development, the normality of cleavage and the ploidy state are closely related to the final clinical outcome. At present, many research teams are focusing on the combined application of timelapse (TL) technology and preimplantation genetic testing (PGT) technology, hoping to find a connection between the two aspects of morphodynamics and genes. In the process of embryonic cleavage, there is a common abnormal cleavage pattern called reverse cleavage (RC). RC refers to blastomere fusion and failed cytokinesis. There are very few reports about it. Whether the occurrence of RC affects blastocyst euploidy is even less clear. Whether the RC phenomenon affects the embryonic developmental potential and whether it is related to the embryo ploidy. This is important for clinicians and embryologists. In this study, we used TL to observe whether there was a phenomenon of RC in each biopsy embryo and then combined it with the ploidy state to give an answer, which provided support for the selection strategy of RC embryos.

Methods

A total of 405 TL-PGT cycles and 1,467 blastocysts were included in the study. All TL data were collected from the Reproductive Medicine Center, Huazhong University of Science and Technology Hospital. Embryos images throughout embryonic development, from post-insemination to day 5 or 6 until biopsy and cryopreservation, were acquired by the Embryoscope Plus TL microscopy system from January 2019 to December 2020. This study investigated the overall incidence of RC during cleavage; the relationship between RC phenomenon and the number of occurrences and ploidy results; the relationship between RC occurrence and blastocyst developmental quality, as well as the dynamics of RC embryos.

Results

Among the 1,453 blastocysts biopsied, 400 blastocysts showed RC phenomenon at the cleavage stage, and the incidence rate was 25.9%. In euploid, mosaic and aneuploid embryos, the incidence of RC was 27.2%, 26.6%, and 25.0%, respectively. The incidence of RC was similar among these three groups with no significant difference (P > 0.05). The number of RC occurrences was not associated with embryo ploidy status (P > 0.05). In general, the blastocyst quality of the RC + group was lower than that of the RC- group. In the ICM score, the proportion of A score in the RC + group was significantly lower than that in RC- group (P < 0.05). In the TE score, there was no significant difference between the two groups of A-grade blastocysts, but the proportion of B-grade blastocysts in the RC + group was significantly lower than that in the RC- group (P < 0.01). In terms of developmental kinetic parameters, the cleavage synchrony parameters s2 and s3 were significantly longer in RC + embryos than in RC- embryos (P < 0.05). However, these changes in kinetic parameters were not significantly different between the euploid, mosaic and aneuploid groups.

Conclusions

The chromosomal euploidy of cleavage-stage embryos with RC phenomenon developed to the blastocyst stage was not significantly different from that of cleavage normal blastocysts. Therefore, RC embryos should not be discarded. It is recommended to select and utilize blastocyst culture, which has similar clinical value to normal cleavage embryos.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-022-01026-9.

Oocyte Cryopreservation in Patients with Endometriosis: Current Knowledge and Number Needed to Treat

The rise of oocytes cryopreservation (OOC) in assisted reproductive techniques allows fertility preservation (FP) in an increasing number of indications. Endometriosis, a highly prevalent disease, potentially impairing ovarian reserve, seems, therefore, an interesting indication for it. The purpose of this study is to summarize the available evidence concerning FP by OOC in women with endometriosis and to calculate the number needed to treat (NNT). In total, 272 articles related to this topic were identified in PubMed. Eight studies were eligible for the review. In order to shed some light, a SWOT analysis was performed and the argument pros and cons were developed. The NNT calculated of OOC was 16, meaning that 16 women need to perform an OOC for one of them to have a child that she would not have had without this technique. In conclusion, OOC must be discussed with patients who suffer from endometriosis since it is an effective technique of FP, which can allow these patients to succeed a pregnancy that they otherwise would not have achieved. Nevertheless, it should not be performed in all patients as there is still a lack of robust socio-economic and risk–benefit data.

Factors affecting clinical outcomes after IVF-ET for infertile young patients with ovarian endometrioma: A 5-year retrospective cohort study

This study aimed to compare ovarian reserve function and outcomes after in vitro fertilization and embryo transfer (IVF-ET) for young women with pelvic endometriosis with or without ovarian endometrioma. We explored the main factors influencing pregnancy outcomes in young patients with endometrioma. A total of 619 patients ≤38 years of age who underwent IVF-ET in our reproductive center between January 2011 and December 2015 were recruited. Among these patients, 398 had pelvic endometriosis with ovarian endometrioma and 221 had pelvic endometriosis without ovarian endometrioma. Patients underwent ovulation induction during IVF-ET. The general conditions and clinical outcomes of IVF-ET treatment were compared. Key factors affecting the success of IVF-ET treatment for endometriomas were analyzed. During IVF-ET treatment, the numbers of retrieved oocytes and 2-pronuclei (2PN) embryos in all age groups (P < .01), and the number of 2PN high-quality embryos in patients under 30 years of age was lower in the pelvic endometriosis with ovarian endometrioma group than in the pelvic endometriosis alone group (P < .05). Logistic regression analysis showed the number of antral follicles, basal follicle-stimulating hormone (bFSH) levels, number of oocytes, number of 2PN embryos, and number of 2PN high-quality embryos were significantly related to the successful outcome of IVF-ET. Among these, the number of 2PN high-quality embryos was the only independent predictive factor. Ovarian endometrioma significantly impairs ovarian reserve function and ultimately affects the therapeutic efficacy of IVF-ET. Obtaining more 2PN high-quality embryos was important for IVF-ET treatment of young patients with ovarian endometriomas.

Association of embryo transfer type with infertility in endometriosis: a systematic review and meta-analysis

PURPOSE

The study aims to evaluate whether frozen embryo transfer can restore optimal receptivity leading to better assisted reproductive technology outcomes in women with endometriosis.

METHODS

This systematic review and meta-analysis, conducted from January 10, 2021 to July 1, 2021, searched the Cochrane Library, PubMed, Embase, Web of Science, OVID, and Clinicaltrials.gov databases from inception to January 10, 2021. The search strategy combined search terms as follows: ("endometriosis" OR "deep endometriosis" OR "endometrioma") AND ("frozen-thawed embryo transfer" OR "frozen embryo transfer" OR "freeze-all strategy") AND ("pregnancy outcome" OR "live birth rate" OR "clinical pregnancy rate" OR "miscarriage rate"). No publication time or language limits were set during the searches. In addition, references of the related articles were searched by hand. Patients were included if they had a history of endometriosis and had received fresh or frozen embryo transfer. Only the first transfer cycle was included. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to express outcomes, and data synthesis was conducted using RevMan, version 5.4 software.

RESULTS

A total of six studies with moderate methodologic quality were retrieved in the meta-analysis. The studies included 3010 women with endometriosis who wanted to conceive; 1777 (59.0%) had frozen embryo transfer, and 1233 (41.0%) had fresh embryo transfer. There was a significantly higher frequency of live births in the frozen embryo group than in the fresh embryo group (OR, 1.53; 95% CI, 1.13-2.08; P = .007). Despite a similar clinical pregnancy rate in the two groups (OR, 1.26; 95% CI, 0.95-1.69; P = .11), the difference in miscarriage rate was significant (OR, 0.70; 95% CI, 0.50-0.97; P = .03). Evidence quality was considered moderate.

CONCLUSION

Cryopreserved embryo transfer has resulted in preferable reproduction outcomes when compared with fresh embryo transfer in patients with endometriosis, but the evidence is not yet abundant. More strictly designed research is needed to evaluate whether frozen embryo transfer leads to better reproductive outcomes in women with endometriosis compared with those receiving fresh embryo transfer.

REGISTRATION NUMBER

PROSPERO CRD42021248313.

Long noncoding RNA ADAMTS9-AS1 represses ferroptosis of endometrial stromal cells by regulating the miR-6516-5p/GPX4 axis in endometriosis

Endometriosis (EMs) is one of the most frequent diseases of reproductive-age women and is characterized by the growth of endometrial tissues beyond the uterus. The enhanced proliferative and migratory potential of endometrial stromal cells (ESCs) plays an important role in the progression of EMs. Mounting studies have demonstrated that long noncoding RNAs (lncRNAs) exert an important role in regulating the development and progression of EMs. Given the aberrant expression of lncRNA ADAMTS9-AS1 in ectopic endometrium (ecEM), we investigated the biological effect of ADAMTS9-AS1 on ESC proliferation and migration and explored the underlying mechanism. The current data showed that ADAMTS9-AS1 expression was significantly upregulated in ecEM compared with eutopic endometrium (euEM) in patients with EMs and in a murine model of EMs. Functionally, ADAMTS9-AS1 knockdown in ectopic ESCs (EESCs) decreased cell viability and migration, whereas ADAMTS9-AS1 overexpression in normal ESCs (NESCs) enhanced cell viability and migration. More importantly, the effect of ADAMTS9-AS1 inhibition on decreasing ESC viability was significantly blocked by ferrostatin-1 (Fer-1, a ferroptosis inhibitor), and ADAMTS9-AS1 overexpression repressed erastin (a ferroptosis activator)-induced cell death. Furthermore, the regulatory role of ADAMTS9-AS1 in ferroptosis was defined and evidenced by increased reactive oxygen species (ROS) levels and malonyl dialdehyde (MDA) content and decreased expression of glutathione peroxidase 4 (GPX4) after ADAMTS9-AS1 inhibition. Mechanistically, ADAMTS9-AS1 functioned as a competing endogenous RNA (ceRNA) by sponging miR-6516-5p to derepress the expression of GPX4, the critical repressor of ferroptosis. Taken together, these results demonstrate that upregulated ADAMTS9-AS1 accelerates ESC proliferation and migration by regulating miR-6516-5p/GPX4-dependent ferroptosis and may be a potential target for the treatment of EMs.