Endometrial receptivity in the eutopic endometrium of women with endometriosis: it is affected, and let me show you why

NEK2 promotes the development of ovarian endometriosis and impairs decidualization by phosphorylating FOXO1

Ovarian endometriosis is a common gynecological disease, and one of its most significant symptoms is infertility. In patients with endometriosis, defects in endometrial decidualization lead to impaired endometrial receptivity and embryo implantation, thus affecting early pregnancy and women's desire to have children. However, the mechanisms underlying the development of endometriosis and its associated defective decidualization are unclear. We find that NEK2 expression is increased in the ectopic and eutopic endometrium of patients with endometriosis. Meanwhile, NEK2 interacts with FOXO1 and phosphorylates FOXO1 at Ser184, inhibiting the stability of the FOXO1 protein. Importantly, NEK2-mediated phosphorylation of FOXO1 at Ser184 promotes cell proliferation, migration, invasion and impairs decidualization. Furthermore, INH1, an inhibitor of NEK2, inhibits the growth of ectopic lesions in mouse models of endometriosis and promotes endometrial decidualization in mouse models of artificially induced decidualization. Taken together, these findings indicate that NEK2 regulates the development of endometriosis and associated disorders of decidualization through the phosphorylation of FOXO1, providing a new therapeutic target for its treatment.

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.

Association between dietary inflammation index and female infertility from National Health and Nutrition Examination Survey: 2013-2018

Objective

To investigate the relationship between dietary inflammatory index (DII) scores and infertility in US adults aged 18 to 45.

Methods

Data were gathered from the 2013-2018 National Health and Nutrition Examination Survey (NHANES). In total, 3496 women were included in the study. To examine the relationship between DII, EDII and infertility, a weighted multivariable logistic regression analysis using continuous factors or categorical variables grouped by quartiles was conducted. Using subgroup analysis stratified based on DII and infertility features, the association between DII and infertility has been further studied. In order to determine whether there was a nonlinear relationship between DII and infertility, restricted cubic spline (RCS) analysis was carried out.

Results

For statistical analysis, a total of 3496 individuals - 367 patients with infertility and 3129 persons without infertility - were included. A multivariable logistic regression study revealed a positive relationship between DII and infertility. A significant difference in subgroup analysis was shown in age group and race, although RCS analysis demonstrated nonlinear relationship between the DII and infertility.

Conclusion

For participants aged 18-45 years, higher DII scores were positively correlated with infertility. In addition, anti-inflammatory diets might improve infertility outcomes.

Transcriptomic changes in eutopic endometrium and ectopic lesions during endometriosis progression in a mouse model

OBJECTIVE

To identify the transcriptomic changes of ectopic lesions and eutopic endometrial tissues during the progression of endometriosis, we performed transcriptomic analysis in the eutopic endometrium and ectopic lesions.

DESIGN

Laboratory study.

SETTING

Academic medical center.

ANIMALS

Four fertile and 4 subfertile Pgrcre/+Rosa26mTmG/+ mice with endometriosis, and 4 sham mice for each group of endometriosis mice as control. These mice underwent either surgery to induce endometriosis or sham surgery. Fertile sham and mice with endometriosis were used 1 month after surgery, whereas subfertile ones were used 3 months after surgery.

INTERVENTIONS

Early and chronic effects of endometriosis on transcriptomics of ectopic lesions and eutopic endometrium.

MAIN OUTCOME MEASURES

RNA-sequencing analysis and identification of differentially expressed genes and pathways in the ectopic lesions and eutopic uteri from mice with endometriosis and sham mice at day 3.5 of pregnancy.

RESULTS

Our mouse model recapitulates the transcriptomic changes of ectopic lesions in humans. RNA-sequencing analysis was performed in ectopic lesions and eutopic uteri from mice with or without endometriosis during the progression of the disease. Estrogen activity, inflammation, angiogenesis, and fibrosis pathways were consistently elevated in all the ectopic lesions compared with eutopic endometrium. Cholesterol/glucose synthesis and stem cell pluripotency pathways were more enhanced in ectopic lesions from subfertile mice compared with their eutopic endometrium. Dysregulation of infiltration of macrophage, dendritic, T and B cells was validated with the use of immunohistochemistry in ectopic lesions. Multiple ligand-receptor pairs between the ectopic and eutopic endometrium were altered compared with the sham endometrium. Suppressed WNT and EGF pathways were only found in the eutopic endometrium from subfertile not fertile mice compared with sham.

CONCLUSIONS

Our mouse endometriosis model recapitulates the transcriptomics of ectopic lesions in humans. Our transcriptomic analysis during endometriosis progression in our mouse model will help us understand the pathophysiology of endometriosis.

High Dietary Inflammatory Index increases the risk of female infertility: An analysis of NHANES 2013-2018

Diet-related inflammation, which can be evaluated using the dietary inflammatory index (DII), is increasingly related to female infertility. However, studies on the association between DII and infertility are limited. In this study, we aim to explore the association between DII and infertility and its dose-effect relationship among women aged 20 to 45 years through a cross-sectional analysis of the National Health and Nutrition Examination Survey 2013-2018. A total of 2613 women aged 20 to 45 years were included and analyzed. The DII was calculated using the first 24-hour dietary recall interview data and divided into quartiles. Weighted multivariable logistic regression and restricted cubic spline analysis were used to explore the relationship between DII and infertility. The odds ratio (OR) (95% confidence interval [CI]) for the association between DII and infertility was 1.06 (0.96-1.19) after multivariable adjustment. Compared with the first quartile (anti-inflammatory diet), the fourth quartile of DII (pro-inflammatory diet) was more strongly associated with an increased risk of infertility, with an OR of 1.61 (95% CI, 1.05-2.47). Restricted cubic splines showed a J-shaped nonlinear association between DII and infertility (P for nonlinear = .003), with a cutoff point of 2.45. When DII was higher than 2.45, the OR for infertility was 1.95 (95% CI, 1.49-2.54). Similar results were observed among the subgroup analyses. In conclusion, this study found high DII (pro-inflammatory diet) increases the risk of female infertility. DII had a J-shaped nonlinear relationship with female infertility, whose cut point is 2.45. Controlling the intake of pro-inflammatory food may be beneficial for female infertility.

Loss of KLF15 impairs endometrial receptivity by inhibiting EMT in endometriosis

The impaired endometrial receptivity is a major factor contributing to infertility in patients with endometriosis (EM), but the underlying mechanism remains unclear. Our study aimed to investigate the role of Kruppel-like factor 15 (KLF15) in endometrial receptivity and its regulation in EM. We observed a significant decrease in KLF15 expression in the mid-secretory epithelial endometrial cells of EM patients compared to normal females without EM. To confirm the role of KLF15 in endometrial receptivity, we found a significantly reduced KLF15 expression and a significant decrease in embryo implantation number in the rat model via uterine horn infection with siRNA. This highlights the importance of KLF15 as a regulator receptivity. Furthermore, through ChIP-qPCR, we discovered that the progesterone receptor (PR) directly binds to KLF15 promoter regions, indicating that progesterone resistance may mediate the decrease in KLF15 expression in EM patients. Additionally, we found that the mid-secretory endometrium of EM patients exhibited impaired epithelial-mesenchymal transition (EMT). Knockdown of KLF15 upregulated E-cadherin and downregulated vimentin expression, leading to inhibited invasiveness and migration of Ishikawa cells. Overexpression KLF15 promotes EMT, invasiveness, and migration ability, and increases the attachment rate of JAR cells to Ishikawa cells. Through RNA-seq analysis, we identified TWIST2 as a downstream gene of KLF15. We confirmed that KLF15 directly binds to the promoter region of TWIST2 via ChIP-qPCR, promoting epithelial cell EMT during the establishment of endometrial receptivity. Our study reveals the involvement of KLF15 in the regulation of endometrial receptivity and its downstream effects on EMT. These findings provide valuable insights into potential therapeutic approaches for treating non-receptive endometrium in patients with EM.

The adenomyosis/endometriosis IVF patient - call for clinical focus

Endometriosis and adenomyosis are distinct clinical conditions that carry the same pathophysiological features. In recent years the clinical focus on assisted reproductive technology patients with either condition (E/A) has increased, in the recognition that this subgroup of patients might need special attention to obtain reproductive success. Endometriosis and adenomyosis are characterized by a disruption of progesterone and oestrogen signalling pathways, resulting in local oestrogen dominance and progesterone resistance at the receptor level. Recent scientific evidence suggests that the endometrial progesterone receptor resistance encountered in E/A patients can be overcome by a freeze-all policy, followed by down-regulating circulating oestradiol concentrations prior to frozen embryo transfer (FET), in combination with an increase in exogenous luteal phase progesterone supplementation in hormonal replacement therapy (HRT) FET cycles. Specifically, for adenomyosis patients who do not respond to gonadotrophin-releasing hormone agonist down-regulation in terms of a decrease in circulating oestradiol concentrations, a small case series has suggested that the addition of an aromatase inhibitor for 21 days prior to HRT-FET is a valid option. Endometriosis and adenomyosis are hormonally active diseases, which need to be treated by controlling local hyperoestrogenism and progesterone resistance. Based on physiology and recent preliminary clinical data, the authors of this opinion paper wish to stimulate discussion and spark interest in research in E/A patients.

Predictive Role of Progesterone Levels for IVF Outcome in Different Phases of Controlled Ovarian Stimulation for Patients With and Without Endometriosis: Expert View

The study aimed to review the role of basal, trigger, and aspiration day progesterone levels (PLs) as predictors of in vitro fertilization (IVF) success for patients with and without endometriosis. A non-systematic review was conducted by searching papers published in English during the period of 1990-2023 in MEDLINE and PubMed, Embase, The Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register), and Web of Science. The most widely used IVF predictor success was the trigger day progesterone serum level. Many studies utilize the threshold level of 1.5-2.0 ng/ml. However, the predictive power of only progesterone level failed to show high sensitivity and specificity. Contrary, progesterone level on the trigger day combined with the number of mature retrieved oocytes had the highest predictive power. High baseline progesterone level was associated with poor IVF outcomes. Research on progesterone and IVF success in patients with endometriosis is limited but indicates that endometriosis patients seem to benefit from higher progesterone concentrations (≥ 37.1 ng/ml) in IVF cycles. Currently, there is limited data for a definitive insight into the mportance of progesterone in the estimation of IVF success. Nonetheless, this summarized evidence could serve as up-to-date guidance for the role of progesterone in the prediction of IVF outcomes, both in patients with and without endometriosis.

The involvement of RNA N6-methyladenosine and histone methylation modification in decidualization and endometriosis-associated infertility

Defective decidualization of endometrial stromal cells (ESCs) in endometriosis (EM) patients leads to inadequate endometrial receptivity and EM-associated infertility. Hypoxia is an inevitable pathological process of EM and participates in deficient decidualization of the eutopic secretory endometrium. Enhancer of zeste homology 2 (EZH2) is a methyltransferase which catalyses H3K27Me3, leading to decreased expression levels of target genes. Although EZH2 expression is low under normal decidualization, it is abundantly increased in the eutopic secretory endometrium of EM and is induced by hypoxia. Chromatin immunoprecipitation-PCR results revealed that decidua marker IGFBP1 is a direct target of EZH2, partially explaining the increased levels of histone methylation modification in defected decidualization of EM. To mechanism controlling this, we examined the effects of hypoxia on EZH2 and decidualization. EZH2 mRNA showed decreased m6 A modification and increased expression levels under hypoxia and decidualization combined treatment. Increased EZH2 expression was due to the increased expression of m6 A demethylase ALKBH5 and decreased expression of the m6 A reader protein YTHDF2. YTHDF2 directly bind to the m6 A modification site of EZH2 to promote EZH2 mRNA degradation in ESCs. Moreover, selective Ezh2 depletion in mouse ESCs increased endometrial receptivity and improved mouse fertility by up-regulating decidua marker IGFBP1 expression. This is the first report showing that YTHDF2 can act as a m6 A reader to promote decidualization by decreasing the stability of EZH2 mRNA and further increasing the expression of IGFBP1 in ESCs. Taken together, our findings highlight the critical role of EZH2/H3K27Me3 in decidualization and reveal a novel epigenetic mechanism by which hypoxia can suppress EM decidualization by decreasing the m6 A modification of EZH2 mRNA.

The Efficacy and Safety of Transvaginal Ethanol Sclerotherapy in the Treatment of Endometrial Cysts-A Systematic Review

Endometriosis, as a chronic disorder that is a source of severe pain ailments and infertility, requires a comprehensive therapeutic approach. Sclerotherapy, consisting of the administration of sclerosing agents into the cyst, is a constantly evolving minimally invasive treatment method for this disease. Hence, the main objective of this systematic review was to evaluate the impact of its most often used variant, transvaginal ethanol sclerotherapy, on endometriosis-related symptoms, endometrial cyst recurrence rate, ovarian reserve, assisted reproductive technology (ART) outcomes, and pregnancy outcomes, as well as to assess potential complications resulting from this treatment. This systematic review was undertaken using PubMed, Scopus, Web of Science, and Cochrane Library databases on 24 November 2023. The risk of bias in included studies was assessed with the use of the Newcastle-Ottawa scale (NOS) and the revised Cochrane risk of bias 2.0 tool for randomized controlled trials. From the 1141 records obtained from all databases, 16 studies have been included in this review. The use of ethanol sclerotherapy was characterized by a low rate of post-procedural complications. The recurrence rate of endometrial cysts after the procedure depended on the ethanol instillation time within the cyst. Although ethanol sclerotherapy had negligible influence on ovarian reserves when compared to laparoscopic cystectomy, the effects of both these methods on pregnancy outcomes were comparable. This review identifies that sclerotherapy is safe, provides significant relief of symptoms, and does not impair the reproductive potential of the patients.

Implantation and Decidualization in PCOS: Unraveling the Complexities of Pregnancy

Polycystic Ovary Syndrome (PCOS) is a prevalent endocrine disorder in women of reproductive age, affecting 5-15% globally with a large proportion undiagnosed. This review explores the multifaceted nature of PCOS and its impact on pregnancy, including challenges in fertility due to hormonal imbalances and insulin resistance. Despite restoring ovulation pharmacologically, women with PCOS face lower pregnancy rates and higher risks of implantation failure and miscarriage. Our review focuses on the complexities of hormonal and metabolic imbalances that impair endometrial receptivity and decidualization in PCOS. Disrupted estrogen signaling, reduced integrity of endometrial epithelial tight junctions, and insulin resistance impair the window of endometrial receptivity. Furthermore, progesterone resistance adversely affects decidualization. Our review also examines the roles of various immune cells and inflammatory processes in the endometrium, contributing to the condition's reproductive challenges. Lastly, we discuss the use of rodent models in understanding PCOS, particularly those induced by hormonal interventions, offering insights into the syndrome's impact on pregnancy and potential treatments. This comprehensive review underscores the need for advanced understanding and treatment strategies to address the reproductive complications associated with PCOS, emphasizing its intricate interplay of hormonal, metabolic, and immune factors.

Association between endometriosis and obstetric complications: Insight from the National Inpatient Sample

OBJECTIVE

This study aimed to investigate the relationship between endometriosis and adverse obstetric outcomes using data from the National Inpatient Sample (NIS) database.

METHODS

The ICD-10 coding system was used to identify codes for endometriosis and obstetric outcomes, and data from the NIS (2016-2019) were analyzed. Descriptive statistics were used to summarize variables, while the chi-square test was used to detect significant differences for categorical variables. Univariate and multivariate regression analyses were conducted to assess the association between endometriosis and obstetric outcomes. On multivariate analysis, adjustment was done for age, race, hospital region, smoking status, and alcohol misuse. Forest plots were used to visualize odds ratios and their 95% confidence intervals.

RESULTS

Overall, 2,854,149 women were included in this analysis, of whom 4,006 women had endometriosis. The post-hoc Bonferroni correction was applied to account for multiple comparisons, and our analyses revealed several statistically significant associations (p < 0.004). Specifically, on univariate analysis, significant associations with endometriosis were identified for ruptured uterus, placenta previa, placental abruption, postpartum hemorrhage, preeclampsia, amniotic fluid abnormality, gestational diabetes, preterm labor, and multiple gestation. On multivariate analysis, significant associations with endometriosis were observed for placenta previa, placental abruption, postpartum hemorrhage, preeclampsia, amniotic fluid abnormality, preterm labor, premature rupture of membranes, and multiple gestation.

CONCLUSION

The present findings provide important insights into the potential relationship between endometriosis and various adverse obstetric outcomes and may help inform clinical practice and future research. Further studies that use more detailed clinical data and longitudinal designs are needed to solidify the presented conclusions.

Endometriosis affects the number of retrieved oocytes but not early embryonic development and live birth: a retrospective analysis of 716 IVF cycles

To investigate the potential effect of endometriosis on embryo development and clinical outcomes, a retrospective analysis of 716 women undergoing their first standard in vitro fertilization (sIVF) cycles (205 endometriosis and 511 with tubal factor infertility) was performed. The endometriosis group included women with an ultrasonographic or surgical diagnosis. Control subjects were women diagnosed with tubal factor infertility by laparoscopy or hysterosalpingogram. The primary outcome of the study was live birth. Cumulative live birth was also assessed in a subgroups analysis. After adjusting for confounders we found no significant difference in fertilization rate, blastulation, top-quality blastocyst, live birth, cumulative live birth (subgroups analysis) and miscarriage rate. In the endometriosis group, the number of retrieved oocytes was smaller (6.94 ± 4.06 Vs 7.50 ± 4.6, adjusted p < 0.05). We observed a statistically significant difference in the percentage of day-3 embryos with ≥8 blastomeres (33.12 ± 22.72 endometriosis vs, 40.77 ± 27.62 tubal factor, adjusted p < 0.01) and a negative correlation between the presence of endometriomas and a number of retrieved oocytes [B coefficient =-1.41, 95%CI (-2.31-0.51), adjusted p = 0.002]. Our results suggest that endometriosis affects the number of retrieved oocytes but not embryo development and live birth.

Increased Expression of TGF-β1 Contributes to the Downregulation of Progesterone Receptor Expression in the Eutopic Endometrium of Infertile Women with Minimal/Mild Endometriosis

Endometriosis is a hormone-dependent disease associated with impaired immunoregulation. In our recent study, we have characterized the trascriptomic transformation of eutopic endometrium from patients with minimal/mild endometriosis and controls across the menstrual cycle. However, the regulatory mechanism of altered immune microenvironment in eutopic endometrial stromal cells (ESCs) remains unclear. Here, we want to explore the regulation of immune cell to progesterone resistance and endometrial receptivity in the eutopic ESCs by cytokine (TGF-β1), and to understand the effect of TGF-β1 on the decidualization of the eutopic ESCs. Primary culture of eutopic ESCs was performed to explore the effects of TGF-β1 on the expression of Smad and progesterone receptor (PR) and the in vitro decidualization. Additionally, co-immunoprecipitation (Co-IP) was used to explore the direct interaction between Smad and PR. We found an attenuate expression of PRB protein (p=0.026) after using TGF-β1 in eutopic ESCs, although the difference of PRA before and after treatment was not significant (p=0.678). Similarly, the results of qRT-PCR showed that the mRNA level of PR (p<0.001), PRB (p=0.003) and HOXA10 (p<0.001) decreased significantly after TGF-β1 treatment, but that increased (p<0.023, for all) after SB431542 treatment in the eutopic ESCs. Moreover, TGF-β1 has a negative effect on the in vitro decidualization of eutopic ESCs (p=0.003). And the group with treatment of both TGF-β1 and SB435142 in eutopic ESCs showed significant decidual-like changes with increased prolactin level (p=0.01). We did not observe any physical interaction between the PR and p-Smad3/Smad3 proteins by using Co-IP. By activating TGF-β/Smad signaling in eutopic ESCs, elevated TGF-β1 from CD45+ immune cells could attenuate expression of PR, and further decrease endometrial receptivity.

Epigenetic Dysregulation in Endometriosis: Implications for Pathophysiology and Therapeutics

Endometriosis is a prevalent gynecological condition associated with pelvic pain and infertility. Despite more than a century of research, the etiology of endometriosis still eludes scientific consensus. This lack of clarity has resulted in suboptimal prevention, diagnosis, and treatment options. Evidence of genetic contributors to endometriosis is interesting but limited; however, significant progress has been made in recent years in identifying an epigenetic role in the pathogenesis of endometriosis through clinical studies, in vitro cell culture experiments, and in vivo animal models. The predominant findings include endometriosis-related differential expression of DNA methyltransferases and demethylases, histone deacetylases, methyltransferases, and demethylases, and regulators of chromatin architecture. There is also an emerging role for miRNAs in controlling epigenetic regulators in the endometrium and endometriosis. Changes in these epigenetic regulators result in differential chromatin organization and DNA methylation, with consequences for gene expression independent of a genetic sequence. Epigenetically altered expression of genes related to steroid hormone production and signaling, immune regulation, and endometrial cell identity and function have all been identified and appear to play into the pathophysiological mechanisms of endometriosis and resulting infertility. This review summarizes and critically discusses early seminal findings, the ever-growing recent evidence of epigenetic contributions to the pathophysiology of endometriosis, and implications for proposed epigenetically targeted therapeutics.

Exosomal microRNAs and long noncoding RNAs: as novel biomarkers for endometriosis

Endometriosis is a gynecological inflammatory disorder characterized by the development of endometrial-like cells outside the uterine cavity. This disease is associated with a wide range of clinical presentations, such as debilitating pelvic pain and infertility issues. Endometriosis diagnosis is not easily discovered by ultrasound or clinical examination. Indeed, difficulties in noninvasive endometriosis diagnosis delay the confirmation and management of the disorder, increase symptoms, and place a significant medical and financial burden on patients. So, identifying specific and sensitive biomarkers for this disease should therefore be a top goal. Exosomes are extracellular vesicles secreted by most cell types. They transport between cells' bioactive molecules such as noncoding RNAs and proteins. MicroRNAs and long noncoding RNAs which are key molecules transferred by exosomes have recently been identified to have a significant role in endometriosis by modulating different proteins and their related genes. As a result, the current review focuses on exosomal micro-and-long noncoding RNAs that are involved in endometriosis disease. Furthermore, major molecular mechanisms linking corresponding RNA molecules to endometriosis development will be briefly discussed to better clarify the potential functions of exosomal noncoding RNAs in the therapy and diagnosis of endometriosis.

Impact of moderate-to-severe endometriosis on IVF cumulative live birth rate: a retrospective matched cohort study

RESEARCH QUESTION

Does moderate-to-severe endometriosis have an impact on cumulative live birth rates (cLBR) and IVF outcomes?

DESIGN

In this retrospective matched cohort study, women with moderate-to-severe endometriosis undergoing IVF or intracytoplasmic sperm injection treatment from January 2015 to December 2020 were matched 1:2 to women with other causes of infertility (control group). The main outcome was cLBR per cycle and per woman, and secondary outcomes were number of oocytes retrieved and number of mature oocytes, fertilization rate, total number of embryos and usable embryos, implantation rate, clinical pregnancy rate and miscarriage rate per cycle.

RESULTS

In total, 195 women with endometriosis were matched with 390 women without endometriosis (323 and 646 cycles, respectively). Women with endometriosis had significantly fewer oocytes retrieved than women in the control group (P=0.003) despite higher doses of gonadotropins, but had a similar number of mature oocytes, fertilization rate, and total number of embryos and usable embryos. cLBR per cycle and per women did not differ significantly between the endometriosis group and the control group (19.8% versus 24.3%, P = 0.12; 32.3% versus 37.2%, P = 0.24, respectively). In women with endometrioma, a history of cystectomy did not impact cLBR per cycle (28.3% versus 31.9%, P = 0.68). We did not observe any significant impact of tobacco use in the endometriosis group compared with the control group (16.4% versus 25.9%, P = 0.13).

CONCLUSION

This matched cohort study did not observe a significant impact of moderate-to-severe endometriosis on cLBR among women undergoing IVF. These data are reassuring for the counselling of infertile women with endometriosis before IVF.

Cumulative pregnancy rate via multiple fresh or frozen embryo transfers in women with current, resected, or recurred endometrioma

OBJECTIVE

This study aimed to retrospectively analyze the cumulative pregnancy rate (PR) via multiple fresh or frozen embryo transfers (ET) in women with current, resected, or recurred endometrioma.

MATERIALS AND METHODS

The IVF data including oocyte pick-up (OPU) and fresh or frozen ET in women with current (37 women; 56 OPU, 18 fresh and 14 frozen ET), resected (24 women; 50 OPU, 17 fresh and 42 frozen ET), or recurred endometrioma (28 women; 49 OPU, 22 fresh and 24 frozen ET) were obtained. All cycles were performed from 2015 to 2022 in a single university hospital.

RESULTS

The median serum AMH level (ng/mL) was 1.44, 1.47, and 0.98, respectively. The number of total or mature oocytes, fertilized oocytes, cleavage embryos at day-3, and top-quality embryos at day-3 were all similar in the three groups. Cycles with no oocyte occurred in 2 (3.6%), 1 (2%), and 3 cycles (6.1%), respectively. Freeze-all was performed in 46.3%, 59.2%, and 47.8% of the cycles, respectively (p > 0.05). The cumulative clinical PR per total ET (43.8%, 25.4%, and 21.7%), per OPU (25%, 30%, and 20.4%), and per woman (37.8%, 62.5%, and 35.7%) were all similar in the three groups. The cumulative ongoing pregnancy and live birth rate per total ET, per OPU, and per woman were also similar in the three groups.

CONCLUSION

Similarity in ovarian reserve, number of oocytes, number of embryos, cumulative clinical PR, and live birth in the three endometriosis groups indicates that the IVF outcomes in the 'recurrent endometrioma' group are not inferior to 'current' or 'resected' group.

Using organoids to investigate human endometrial receptivity

The human endometrium is only receptive to an implanting blastocyst in the mid-secretory phase of each menstrual cycle. Such time-dependent alterations in function require intricate interplay of various factors, largely coordinated by estrogen and progesterone. Abnormal endometrial receptivity is thought to contribute to two-thirds of the implantation failure in humans and therefore significantly hindering IVF success. Despite the incontrovertible importance of endometrial receptivity in implantation, the precise mechanisms involved in the regulation of endometrial receptivity remain poorly defined. This is mainly due to a lack of proper in vitro models that recapitulate the in vivo environment of the receptive human endometrium. Organoids were recently established from human endometrium with promising features to better mimic the receptive phase. Endometrial organoids show long-term expandability and the capability to preserve the structural and functional characteristics of the endometrial tissue of origin. This three-dimensional model maintains a good responsiveness to steroid hormones in vitro and replicates key morphological features of the receptive endometrium in vivo, including pinopodes and pseudostratified epithelium. Here, we review the current findings of endometrial organoid studies that have been focused on investigating endometrial receptivity and place an emphasis on methods to further refine and improve this model.

Expression of HOXA10 Gene in Women with Endometriosis: A Systematic Review

The homeobox A10 (HOXA10) gene is known to be related to endometriosis; however, due to a lack of knowledge/evidence in the pathogenesis of endometriosis, the mechanisms that link HOXA10 to endometriosis still need to be clarified. This review addresses the difference in the expression of the HOXA10 gene in endometriotic women versus non-endometriotic women across populations by country and discusses its influences on women's fertility. An organized search of electronic databases was conducted in Scopus, ScienceDirect, PubMed, and Web of Science. The keywords used were (HOXA10 OR "homeobox A10" OR PL OR HOX1 OR HOX1H OR HOX1.8) AND ("gene expression") AND (endometriosis). The initial search resulted in 623 articles, 10 of which were included in this review. All ten papers included in this study were rated fair in terms of the quality of the studies conducted. The expression of the HOXA10 gene was found to be downregulated in most studies. However, one study provided evidence of the downregulation and upregulation of HOXA10 gene expression due to the localization of endometriotic lesions. Measuring the expression of the HOXA10 gene in women is clinically essential to predicting endometriosis, endometrial receptivity, and the development of pinopodes in the endometrium during the luteal phase.

Surgical management of endometriosis to optimize fertility

PURPOSE OF REVIEW

Surgery is an integral element of treatment for infertility caused by endometriosis. This review summarizes the purported mechanisms of infertility in endometriosis, as well as the impacts of surgery for endometriosis on fertility, including pregnancy achieved spontaneously and with assisted reproductive technology (ART).

RECENT FINDINGS

Endometriosis' effect on fertility is multifactorial. The sequela of increased inflammation resulting from endometriosis causes alterations in ovarian, tubal, and uterine function. Removing or destroying these lesions reduces inflammation. Surgical treatment of both early-stage endometriosis and deeply infiltrating endometriosis improves spontaneous pregnancy rates and ART pregnancy rates. Conventional or robotic laparoscopy is the preferred surgical approach.

SUMMARY

Endometriosis has detrimental effects on fertility, including negative impacts on oocyte, tubal, and endometrial function. Laparoscopic surgery for endometriosis elevates both spontaneous and ART pregnancy rates above those achieved with expectant management alone. The resection or destruction of endometriosis implants reduces inflammation, which likely improves the multifactorial infertility related to endometriosis. This topic is complex and controversial; more research in the form of high-quality randomized control trials is needed.

The role of CD8+ T cells in endometriosis: a systematic review

Background

Endometriosis is a chronic disease affecting 6-10% of women of reproductive age. It is an important cause of infertility and chronic pelvic pain with poorly understood aetiology. CD8+ T (CD8 T) cells were shown to be linked to infertility and chronic pain and play a significant role in lesion clearance in other pathologies, yet their function in endometriosis is unknown. We systematically evaluated the literature on the CD8 T in peripheral blood and endometriosis-associated tissues to determine the current understanding of their pathophysiological and clinical relevance in the disease and associated conditions (e.g. infertility and pelvic pain).

Methods

Four databases were searched (MEDLINE, EMBASE, Web of Science, CINAHL), from database inception until September 2022, for papers written in the English language with database-specific relevant terms/free-text terms from two categories: CD8 T cells and endometriosis. We included peer-reviewed papers investigating CD8 T cells in peripheral blood and endometriosis-associated tissues of patients with surgically confirmed endometriosis between menarche and menopause, and animal models with oestrous cycles. Studies enrolling participants with other gynaecological pathologies (except uterine fibroids and tubal factor infertility used as controls), cancer, immune diseases, or taking immune or hormonal therapy were excluded.

Results

28 published case-control studies and gene set analyses investigating CD8 T cells in endometriosis were included. Data consistently indicate that CD8 T cells are enriched in endometriotic lesions in comparison to eutopic endometrium, with no differences in peripheral blood CD8 T populations between patients and healthy controls. Evidence on CD8 T cells in peritoneal fluid and eutopic endometrium is conflicting. CD8 T cell cytotoxicity was increased in the menstrual effluent of patients, and genomic analyses have shown a clear trend of enriched CD8 T effector memory cells in the eutopic endometrium of patients.

Conclusion

Literature on CD8 T cells in endometriosis-associated tissues is inconsistent. Increased CD8 T levels are found in endometriotic lesions, however, their activation potential is understudied in all relevant tissues. Future research should focus on identifying clinically relevant phenotypes to support the development of non-invasive diagnostic and treatment strategies.

Systematic Review Registration

PROSPERO identifier CRD42021233304.

Effect of atosiban on in vitro fertilization pregnancy outcome among women with endometriosis in presence or absence of adenomyosis

OBJECTIVE

This study aimed to assess the effect of atosiban on in vitro fertilization (IVF) pregnancy outcome among women with both endometriosis and adenomyosis, and compared it to that of patients with endometriosis but without adenomyosis and that of patients with tubal factor only.

MATERIALS AND METHODS

106 infertile women (176 embryo transfers) from a medical center in Taiwan were included in the analysis, where 34 (54), 34 (66), and 38 (56) cases (embryo transfers) were endometriosis without adenomyosis, endometriosis with adenomyosis, and tubal infertility factor only, respectively. Adenomyosis morphologies were classified using an ultrasound-based classification system. The logistic generalized estimating equation model was used to analyze the association between atosiban use and pregnancy outcomes.

RESULTS

The crude pregnancy rates for the endometriosis-only group were significantly higher than those for the endometriosis + adenomyosis group (i.e., biochemical pregnancy: 50.0% versus 29.7%, p = 0.041; ongoing pregnancy: 35.2% versus 16.9%, p = 0.038). Significantly higher chances of biochemical pregnancy and ongoing pregnancy among endometriosis patients without adenomyosis versus those with both endometriosis and adenomyosis were found (odds ratios [95% confidence intervals]: 2.981 [1.307, 6.803]; p = 0.009, 2.694 [1.151, 6.304]; p = 0.022). A significant positive association between atosiban use and biochemical pregnancy existed among endometriosis cases without adenomyosis (a 2.43-fold [1.01, 5.89] increase in successful pregnancy; p<0.05), but not for the other groups.

CONCLUSIONS

Poor pregnancy outcomes among adenomyosis-affected women were confirmed. The use of atosiban significantly enhanced IVF pregnancy among endometriosis patients without adenomyosis.

METTL3-dependent m6A methylation facilitates uterine receptivity and female fertility via balancing estrogen and progesterone signaling

Infertility is a worldwide reproductive health problem and there are still many unknown etiologies of infertility. In recent years, increasing evidence emerged and confirmed that epigenetic regulation played a leading role in reproduction. However, the function of m⁶A modification in infertility remains unknown. Here we report that METTL3-dependent m⁶A methylation plays an essential role in female fertility via balancing the estrogen and progesterone signaling. Analysis of GEO datasets reveal a significant downregulation of METTL3 expression in the uterus of infertile women with endometriosis or recurrent implantation failure. Conditional deletion of Mettl3 in female reproductive tract by using a Pgr-Cre driver results in infertility due to compromised uterine endometrium receptivity and decidualization. m⁶A-seq analysis of the uterus identifies the 3'UTR of several estrogen-responsive genes with METTL3-dependent m⁶A modification, like Elf3 and Celsr2, whose mRNAs become more stable upon Mettl3 depletion. However, the decreased expression levels of PR and its target genes, including Myc, in the endometrium of Mettl3 cKO mice indicate a deficiency in progesterone responsiveness. In vitro, Myc overexpression could partially compensate for uterine decidualization failure caused by Mettl3 deficiency. Collectively, this study reveals the role of METTL3-dependent m⁶A modification in female fertility and provides insight into the pathology of infertility and pregnancy management.

CFP1 governs uterine epigenetic landscapes to intervene in progesterone responses for uterine physiology and suppression of endometriosis

Progesterone (P₄) is required for the preparation of the endometrium for a successful pregnancy. P₄ resistance is a leading cause of the pathogenesis of endometrial disorders like endometriosis, often leading to infertility; however, the underlying epigenetic cause remains unclear. Here we demonstrate that CFP1, a regulator of H3K4me3, is required for maintaining epigenetic landscapes of P₄-progesterone receptor (PGR) signaling networks in the mouse uterus. Cfp1^f/f;Pgr-Cre (Cfp1^d/d) mice showed impaired P₄ responses, leading to complete failure of embryo implantation. mRNA and chromatin immunoprecipitation sequencing analyses showed that CFP1 regulates uterine mRNA profiles not only in H3K4me3-dependent but also in H3K4me3-independent manners. CFP1 directly regulates important P₄ response genes, including Gata2, Sox17, and Ihh, which activate smoothened signaling pathway in the uterus. In a mouse model of endometriosis, Cfp1^d/d ectopic lesions showed P₄ resistance, which was rescued by a smoothened agonist. In human endometriosis, CFP1 was significantly downregulated, and expression levels between CFP1 and these P₄ targets are positively related regardless of PGR levels. In brief, our study provides that CFP1 intervenes in the P₄-epigenome-transcriptome networks for uterine receptivity for embryo implantation and the pathogenesis of endometriosis.

A novel therapeutic approach for endometriosis using adipose-derived stem cell-derived conditioned medium- A new hope for endometriotic patients in improving fertility

Introduction

Endometriosis is defined as the growth of endometrial glands and stromal cells in a heterotopic location with immune dysregulation. It usually leads to chronic pelvic pain and subfertility. Although various treatments are available, the recurrence rate remains high. Adipose tissue is an abundant source of multipotent mesenchymal adipose-derived stem cells (ADSCs). ADSCs display effects on not only tissue regeneration, but also immune regulation. Thus, the current study aims to test the effects of ADSCs on the growth of endometriosis.

Methods

ADSCs isolated from lipoaspiration-generated adipose tissue and their conditioned medium (ADSC-CM) were subjected to quality validation, including karyotyping as well as growth promotion and sterility tests for microbial contamination under Good Tissue Practice and Good Manufacturing Practice regulations. An autologous endometriosis mouse model was established by suturing endometrial tissue to peritoneal wall followed by treating with DMEM/F12 medium, ADSC-CM, ADSCs or ADSC-CM+ADSCs for 28 days. The area of endometriotic cysts and the degree of pelvic adhesion were measured. ICAM-1, VEGF and caspase 3 expression was assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry. Moreover, the mice were allowed to mate and deliver. The pregnancy outcomes were recorded. The ADSC-CM was subjected to proteomics analysis with further data mining with Ingenuity Pathway Analysis (IPA).

Results

Both ADSC-CM and ADSCs passed quality validation. ADSC-CM reduced the area of endometriotic cysts. The inhibition by ADSC-CM was obliterated by adding ADSCs. The presence of ADSCs with or without ADSC-CM increased the peritoneal adhesion. ADSC-CM inhibited ICAM-1 and VEGF mRNA and protein expression, whereas the addition of ADSCs not only did not inhibit by itself, but also blocked the inhibition by ADSC-CM. The resorption rate was reduced by ADSC-CM. The number of live birth/dam and the survival rate of pup at 1 week-old were both increased by ADSC-CM in mice with endometriosis. IPA demonstrated that PTX3 was potentially critical for the inhibition of endometriosis by ADSC-CM due to its anti-inflammatory and antiangiogenic properties as well as its importance in implantation.

Conclusion

ADSC-CM inhibited endometriosis development and improved pregnancy outcomes in mice. Potential translation to clinical treatment for human endometriosis is expected.

Novel in vivo endometriotic models associated eutopic endometrium by implanting menstrual blood-derived stromal cells from patients with endometriosis

The eutopic endometrium provides novel insights into endometriotic pathophysiology and treatment. However, no in vivo models currently available are suitable for eutopic endometrium in endometriosis. In this study, we present new endometriotic in vivo models associated with eutopic endometrium using menstrual blood-derived stromal cells (MenSCs). First, we isolated endometriotic MenSCs (E-MenSCs) and healthy MenSCs (H-MenSCs) from the menstrual blood of patients with endometriosis (n = 6) and healthy volunteers (n = 6). Then, we identified MenSCs' endometrial stromal cell properties using adipogenic and osteogenic differentiation. A cell counting kit-8 and wound healing assay were used to compare the proliferation and migration capability between E-MenSCs and H-MenSCs. Seventy female nude mice were used to prepare endometriotic models related to eutopic endometrium by implanting E-MenSCs relying on three approaches, including surgical implantation using scaffolds seeded with MenSCs, and subcutaneous injection of MenSCs in the abdomen and the back (n = 10). H-MenSCs or scaffolds only were implanted in control groups (n = 10). One month after the surgical implantation and 1 week after the subcutaneous injection, we evaluated modeling by hematoxylin-eosin (H&E) and immunofluorescent staining of human leukocyte antigen α (HLAA). Fibroblast morphology, lipid droplets, and calcium nodules in E-MenSCs and H-MenSCs identified their endometrial stromal cell properties. We noticed that the proliferation and migration of E-MenSCs were considerably enhanced compared to H-MenSCs (P < 0.05). E-MenSCs implanted in nude mice formed ectopic lesions using three approaches (n = 10; lesions formation rate: 90%, 115%, and 80%; average volumes: 123.60, 27.37, and 29.56 mm3), while H-MenSCs in the nude mice shaped nothing at the implantation sites. Endometrial glands, stroma, and HLAA expression in these lesions further verified the success and applicability of the proposed endometriotic modeling. Findings provide in vitro and in vivo models and paired controls associated with eutopic endometrium in women with endometriosis using E-MenSCs and H-MenSCs. The approach of subcutaneous injection of MenSCs in the abdomen is highlighted due to non-invasive, simple, and safe steps, a short modeling period (1 week), and an excellent modeling success rate (115%), which could improve the repeats and success of endometriotic nude mice model and shorten the modeling period. These novel models could nearly intimate human eutopic endometrial mesenchymal stromal cells in the progress of endometriosis, opening a new path for disease pathology and treatment.

Concomitant Autoimmunity in Endometriosis Impairs Endometrium-Embryo Crosstalk at the Implantation Site: A Multicenter Case-Control Study

Endometriosis and autoimmune diseases share a hyper-inflammatory state that might negatively impact the embryo-endometrium crosstalk. Inflammatory and immune deregulatory mechanisms have been shown to impair both endometrial receptivity and embryo competence at the implantation site. The aim of this study was to investigate the potential additional impact of co-existing autoimmunity in women affected by endometriosis on the early stages of reproduction. This was a retrospective, multicenter case-control study enrolling N = 600 women with endometriosis who underwent in vitro fertilization-embryo transfer cycles between 2007 and 2021. Cases were women with endometriosis and concomitant autoimmunity matched based on age and body mass index to controls with endometriosis only in a 1:3 ratio. The primary outcome was the cumulative clinical pregnancy rate (cCPR). The study found significantly lower cleavage (p = 0.042) and implantation (p = 0.029) rates among cases. Autoimmunity (p = 0.018), age (p = 0.007), and expected poor response (p = 0.014) were significant negative predictors of cCPR, with an adjusted odds ratio of 0.54 (95% CI, 0.33-0.90) for autoimmunity. These results suggest that the presence of concomitant autoimmunity in endometriosis has a significant additive negative impact on embryo implantation. This effect might be due to several immunological and inflammatory mechanisms that interfere with both endometrial receptivity and embryo development and deserves further consideration.

Intrauterine administration of autologous peripheral blood mononuclear cells regulates the endometrium estrogen and progesterone receptor expression: An RCT

Background

Repeated implantation failure (RIF) affects 15% of women of reproductive age. There is a high endometrial expression of both estrogen receptors and progesterone receptors (PRs) during the window of implantation in women with RIF.

Objective

To evaluate the effects of intrauterine administration of human peripheral blood mononuclear cells (PBMC) on estrogen receptor α (ERα) and PRs expression in the endometrium of women with RIF during the implantation window.

Materials and Methods

This randomized clinical trial study was conducted on 22 women with RIF history from January 2018 to August 2019 in Erfan hospital, Tehran, Iran. Participantswere divided into 2 groups (PBMC-treated group [n = 11] and control group [n = 11]). Endometrial tissue samples were collected at the implantation window time, during the mid-secretory phase (luteinizing hormone surge +7 days) of each menstrual cycle. The quantitative real-time polymerase chain reaction technique was used to measure the mRNA levels of ERα and PRs isoforms (PR-A and PR-B) in endometrial tissues. Furthermore, the protein expression of ERα and PRs was investigated using immunohistochemical staining.

Results

PBMC treatment significantly decreased the mRNA expression of endometrial ERα and PRs isoforms at the time of the implantation window (p < 0.001). Moreover, the endometrial ERα and PRs protein localization were significantly lower in PBMC-treated women compared with controls (p = 0.01, and p < 0.001 respectively).

Conclusion

The intrauterine administration of PBMC decreased the endometrial ERα and PRs expression during the window of implantation in women with RIF. This local response to PBMC therapy could promote endometrial receptivity and embryo implantation.

Review of Endometrial Receptivity Array: A Personalized Approach to Embryo Transfer and Its Clinical Applications

Successful outcomes of in vitro fertilization (IVF) rely on both the formation of a chromosomally normal embryo and its implantation in a receptive endometrium. Pre-implantation genetic testing for aneuploidy (PGT-A) has been widely accepted as a tool to assess the viability of an embryo. In 2011, the endometrial receptivity array (ERA) was first published as a tool to determine when the endometrium is most receptive to an embryo, commonly referred to as the "window of implantation" (WOI). The ERA uses molecular arrays to assess proliferation and differentiation in the endometrium and screens for inflammatory markers. Unlike PGT-A, there has been dissent within the field concerning the efficacy of the ERA. Many studies that contest the success of the ERA found that it did not improve pregnancy outcomes in patients with an already-good prognosis. Alternatively, studies that utilized the ERA in patients with repeated implantation failure (RIF) and transfer of known euploid embryos demonstrated improved outcomes. This review aims to describe the ERA as a novel technique, review the various settings that the ERA may be used in, such as natural frozen embryo transfer (nFET) and hormone replacement therapy frozen embryo transfer (HRT-FET), and provide a summary of the recent clinical data for embryo transfers in patients with RIF utilizing the ERA.

“Shadow of a Doubt”—The Pathogenic Role of Endometrial Defects in Endometriosis Development and Endometriosis-Associated Infertility: Robust Demonstration of Clinical Relevance Is Still Urgently Needed

Endometriosis is an estrogen-dependent chronic inflammatory disease characterized by the presence of endometrial glands and stroma associated with fibrosis outside the uterine cavity [...]

Determinants of Embryo Implantation: Roles of the Endometrium and Embryo in Implantation Success

Both uterine endometrium and embryo contribute to implantation success. However, their relative role in the implantation success is still a matter for debate, as are the roles of endometrial receptivity analysis (ERA), endometrial scratch (ES), endometrial microbiome, and intrauterine or intravenous measures that are currently advocated to improve the implantation success. There is insufficient evidence to suggest that the endometrium is more important than the embryo in determining the implantation success and the utility of these measures, especially when euploid embryos are transferred is limited. Although embryo implantation on epithelium other than the endometrium is a very rare event, evidence suggests that embryo implantation and growth is not limited to the endometrium alone. Embryos can implant and develop to result in livebirths on epithelium that lacks the typical endometrial development present at implantation. Currently, the role of embryo euploidy in implantation success is underappreciated. At a minimum, it is the author's opinion that until robust, definitive studies are conducted that demonstrate benefit, reproductive endocrinologists and infertility specialist should be prudent in the way they counsel patients about the utility of ERA, ES, and other measures in improving implantation success.

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.

Existence of chronic endometritis and its influence on pregnancy outcomes in infertile women with minimal/mild endometriosis

OBJECTIVE

This study aimed to evaluate the prevalence of chronic endometritis (CE) in women with minimal/mild endometriosis and to analyze whether CE affects their pregnancy outcomes.

METHODS

This retrospective study included 201 infertile women who were diagnosed with minimal/mild endometriosis after undergoing hysteroscopy combined with laparoscopy from January 2016 to December 2018. Immunohistochemistry was used to detect CD138 and CD38, which are specific markers of plasma cells in the endometrial stroma to diagnose CE. Subsequently, we investigated the prevalence of CE and the effects of CE on spontaneous cumulative pregnancy rate, live birth rate, and miscarriage rate within 24 months after surgery.

RESULTS

The prevalence of CE in infertile women with minimal/mild endometriosis was 24.38%. Patients diagnosed with CE showed a significantly lower cumulative pregnancy rate and live birth rate compared with women without CE (46.51% vs. 71.13% [P = 0.004]; 44.19% vs. 63.38% [P = 0.025]). However, the rate of miscarriage in women with CE was also lower than in women without CE (0 vs. 7.04%, P = 0.074).

CONCLUSION

Since CE had an adverse effect on cumulative pregnancy rate and live birth rate in infertile women with minimal/mild endometriosis, we suggested that diagnosis and treatment of CE may improve their pregnancy outcomes.

Which endometrial preparation protocol provides better pregnancy and perinatal outcomes for endometriosis patients in frozen-thawed embryo transfer cycles? A retrospective study on 1413 patients

OBJECTIVE

To determine the optimal endometrial preparation protocol for a frozen embryo transfer in patients with endometriosis.

DESIGN

Retrospective cohort study.

SETTING

Tertiary care academic medical center.

PATIENT(S)

One thousand four hundred thirteen patients with endometriosis who underwent oocyte aspiration from 2015 to 2020 and frozen embryo transfer from 2016 to 2020 and received natural cycle, hormone replacement treatment with or without GnRHa pretreatment endometrial preparation.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rate, live birth rate, miscarriage rate, multiple pregnancy rate, biochemical pregnancy rate and ectopic pregnancy rate. Singleton live births were assessed for perinatal outcomes and obstetric complications.

RESULT(S)

There were no differences in clinical pregnancy outcomes or prenatal outcomes among the three commonly used endometrial preparation protocols for frozen embryo transfer cycles in patients with endometriosis. Results remained after screening variables using univariate logistic regression into multivariate logistic regression. No advantages or disadvantages were found among the three endometrial preparation protocols in patients with endometriosis.

CONCLUSION(S)

Natural cycle, hormone replacement cycle, or hormone replacement treatment with GnRHa pretreatment showed no superiority or inferiority in pregnancy and perinatal outcomes in patients with endometriosis.

MLL1:EZH2 Ratio in Uterine Secretions and Endometrial Receptivity in Patients with Endometriosis

OBJECTIVE

To establish a novel approach for diagnosing endometriosis (EM) in patients with impaired endometrial receptivity.

METHOD

Mixed lineage leukemia 1 (MLL1) and enhancer of zeste homolog 2 (EZH2) levels were analyzed. The MLL1:EZH2 ratio in identifying impaired endometrial receptivity has been established and validated.

RESULTS

In normal endometrial tissue, the MLL1:EZH2 ratio increased significantly in the midsecretory phase, compared with that in the proliferative phase. In the midsecretory phase, the MLL1:EZH2 ratio in endometrial tissues and uterine secretions accurately identifies patients with EM who have impaired endometrial receptivity. In the validation group, the sensitivity and specificity of the MLL1:EZH2 ratio in the uterine secretions of the midsecretory phase, in diagnosing patients EM who have impaired endometrial receptivity, were 100% and 96.55%, respectively.

CONCLUSIONS

The MLL1:EZH2 ratio in uterine secretions of the midsecretory phase may serve as a marker to diagnose EM in patients with impaired endometrial receptivity.

Higher Oxidative Stress in Endometriotic Lesions Upregulates Senescence-Associated p16ink4a and β-Galactosidase in Stromal Cells

Endometriosis affects a significant proportion of women worldwide; however, no definitive cure for this disease has been discovered to date. Oxidative stress promotes endometriotic lesion maintenance in the peritoneal cavity in women. Furthermore, there is evidence of the mitogen-activated protein kinase (MAPK) signaling pathway and senescence involvement in the physiopathogenesis of endometriosis. Reactive oxygen species (ROS) cause oxidative damage and are expected to trigger senescence in the endometrium while also causing alterations in MAPK signaling. However, the role of ROS in the senescence-associated phenotype in endometriosis remains unknown. In this context, this study attempted to delineate the pathways linking ROS to senescence in endometrial and endometriotic lesions of healthy individuals and those with endometriosis. Our results indicate a higher presence of ROS in endometriotic lesions, and the upregulation of MAPK. Furthermore, we show that endometriotic lesions in stromal cells stimulated with hydrogen peroxide develop more senescence traits than eutopic and non-endometriosis endometrium. Overall, endometriotic cells respond differently to extracellular distress. Our contribution to further research in this field contributed to the roadmap of endometriosis' search for alternative treatments.

Endometriosis patients benefit from high serum progesterone in hormone replacement therapy-frozen embryo transfer cycles: a cohort study

RESEARCH QUESTION

What is the optimal serum progesterone cut-off level in patients with endometriosis undergoing hormone replacement therapy frozen embryo transfer (HRT-FET) with intensive progesterone luteal phase support?

DESIGN

A cohort study, including 262 HRT-FET cycles in 179 patients all diagnosed with endometriosis either by laparoscopy or by ultrasound in patients with visible endometriomas. Pre-treatment consisted of 42 days of oral contraceptive pills and 5 days' wash-out, followed by 6 mg oral oestrogen daily. Exogenous progesterone supplementation with vaginal progesterone gel 90 mg/12h commenced when the endometrium was 7 mm or thicker. From the fourth day of vaginal progesterone supplementation, patients also received intramuscular progesterone 50 mg daily. Blastocyst transfer was scheduled for the sixth day of progesterone supplementation.

RESULTS

The overall positive HCG, live birth (LBR) and total pregnancy loss rates were 60%, 39% and 34%, respectively. The optimal progesterone cut-off level was 118 nmol/l (37.1 ng/ml) defined as the maximum of the Youden index. The unadjusted LBR was significantly higher in patients with progesterone measuring 118 nmol/l or above compared with patients with progesterone measuring less than 118 nmol/l (51% [44/86] versus 34% [59/176], P = 0.01), whereas the adjusted odds ratio for a live birth was 2.1 (95% CI 1.2 to 3.7) after adjusting for age, body mass index, blastocyst score, blastocyst age, quality and number of blastocysts transferred.

CONCLUSIONS

Serum progesterone levels above 118 nmol/l (37.1ng/ml) resulted in significantly higher LBR compared with lower serum progesterone levels, suggesting that a threshold for optimal serum progesterone exists.

Archimetrosis: the evolution of a disease and its extant presentation : Pathogenesis and pathophysiology of archimetrosis (uterine adenomyosis and endometriosis)

PURPOSE

This article presents a novel concept of the evolution and, thus, the pathogenesis of uterine adenomyosis as well as peritoneal and peripheral endometriosis. Presently, no unifying denomination of this nosological entity exists.

METHODS

An extensive search of the literature on primate evolution was performed. This included comparative functional morphology with special focus on the evolution of the birthing process that fundamentally differs between the haplorrhine primates and most of the other eutherian mammals. The data were correlated with the results of own research on the pathophysiology of human archimetrosis and with the extant presentation of the disease.

RESULTS

The term Archimetrosis is suggested as a denomination of the nosological entity. Archimetrosis occurs in human females and also in subhuman primates. There are common features in the reproductive process of haplorrhine primates such as spontaneous ovulation and corpus luteum formation, spontaneous decidualization and menstruation. These have fused Müllerian ducts resulting in a uterus simplex. Following a usually singleton pregnancy, the fetus is delivered in the skull position. Some of these features are shared by other mammals, but not in that simultaneous fashion. In haplorrhine primates, with the stratum vasculare, a new myometrial layer has evolved during the time of the Cretaceous-Terrestrial Revolution (KTR) that subserves expulsion of the conceptus and externalization of menstrual debris in non-conceptive cycles. Hypercontractility of this layer has evolved as an advantage with respect to the survival of the mother and the birth of a living child during delivery and may be experienced as primary dysmenorrhea during menstruation. It may result in tissue injury by the sheer power of the contractions and possibly by the associated uterine ischemia. Moreover, the lesions at extra-uterine sites appear to be maintained by biomechanical stress.

CONCLUSIONS

Since the pathogenesis of archimetrosis is connected with the evolution of the stratum vasculare, tissue injury and repair (TIAR) turns out to be the most parsimonious explanation for the development of the disease based on clinical, experimental and evolutionary evidence. Furthermore, a careful analysis of the published clinical data suggests that, in the risk population with uterine hypercontractility, the disease develops with a yet to be defined latency phase after the onset of the biomechanical injury. This opens a new avenue of prevention of the disease in potentially affected women that we consider to be primarily highly fertile.

Higher miscarriage rate in subfertile women with endometriosis receiving unbiopsied frozen-warmed single blastocyst transfers

Background: Assisted reproductive technology treatment is recommended to overcome endometriosis-associated infertility but current evidence is controversial. Endometriosis is associated with lower antral follicle count (AFC) and oocyte yield but similar clinical outcomes compared to controls. Unaffected ovarian stimulation response and embryological outcomes but lower clinical pregnancy and live birth rates and higher miscarriage rates have been reported, implying direct impact on endometrial receptivity. With evidence emerging on the benefit of frozen-warmed and blastocyst stage transfer, we investigated ART outcomes in endometriosis using homogeneous case-control groups. Methods: This is a retrospective observational case-control study including n = 66 frozen-warmed unbiopsied single blastocyst transfers of patients with endometriosis and n = 96 of women exhibiting idiopathic sterility. All frozen-warmed transfers followed artificial endometrial preparation. Results: In control women, the mean number of oocytes recovered at oocyte pick up was higher compared to women with endometriosis (15.3 ± 7.1 vs. 12.7 ± 5.2, p = 0.025) but oocyte maturation index (mature oocytes/total oocytes at oocyte pick up) was significantly higher for endometriosis (48.2% vs. 34.0%, p = 0.005). The same was shown for the subgroup of 44 endometriosis patients after endometrioma surgery when compared with controls (49.1% vs. 34.0%, p = 0.014). Clinical pregnancy rate was not higher in endometriosis but was close to significance (47.0% vs. 32.3%, p = 0.059) while live birth rate was comparable (27.3% vs. 32.3%, p = 0.746). Miscarriage rate was higher in the endometriosis group (19.7% vs. 7.3%, p = 0.018). A significantly higher AFC was observed in the control group in comparison with the endometriosis group (16.3 ± 7.6 vs. 13.4 ± 7.0, p = 0.014). Live birth rate did not differ when comparing all endometriosis cases (p = 0.746), ASRM Stage I/II and Stage III/IV (p = 0.348 and p = 0.888) with the control group but the overall pregnancy rate was higher in ASRM Stage I/II (p = 0.034) and miscarriage rate was higher in ASRM Stage III/IV (p = 0.030) versus control. Conclusion: Blastocyst transfers in women with endometriosis originate from cycles with lower AFC but higher share of mature oocytes than in control women, suggesting that endometriosis might impair ovarian reserve but not stimulation response. A higher miscarriage rate, independent of blastocyst quality may be attributed to an impact of endometriosis on the endometrium beyond the timing of implantation.

Assisted biomimetic electrostimulation therapy can improve the clinical pregnancy rate of patients with abnormal endometrial receptivity undergoing frozen-thawed embryo transfer cycles

This study aimed to explore whether assisted biomimetic electrostimulation (BES) therapy can improve clinical outcomes in patients with abnormal endometrial receptivity undergoing frozen-thawed embryo transfer (FET) cycles. We retrospectively collected data from 132 patients who underwent FET cycles and divided them into the BES (n = 86) and non-BES (NBES) groups (n = 46). The clinical pregnancy rate (55.8 vs. 37.0%), biochemical pregnancy rate (59.3 vs. 41.3%), and live birth rate (44.2 vs. 23.9%) of the BES group were significantly higher than those of the NBES group (p < 0.05). No significant difference between the two groups was observed in endometrial thickness at FET day, embryo implantation rate, and early abortion rate (p > 0.05). The logistic regression analysis indicated that blastocyst transfer (adjusted OR = 3.617; 1.337-9.783; p = 0.011) and BES (adjusted OR = 2.398; 1.094-5.256; p = 0.029) were positively associated with the clinical pregnancy rate. These results suggested that assisted BES therapy can improve clinical outcomes in patients with diseases affecting endometrial receptivity.Impact statementWhat is already known on this subject? Biomimetic electrostimulation (BES) therapy can increase endometrial thickness in patients with thin endometria undergoing embryo transfers and to some extent improve their clinical outcomes.What do the results of this study add? Assisted BES therapy can improve clinical pregnancy rates in patients with abnormal endometrial receptivity undergoing FET cycles (55.8 vs. 37.0%, p = 0.039). After adjusting for covariates, BES was still positively associated with the clinical pregnancy rate (adjusted OR = 2.398; 1.094-5.256; p = 0.029).What are the implications of these findings for clinical practice and/or further research? BES therapy can improve endometrial receptivity. Further studies are needed to understand its specific mechanisms.

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.

Comparison of Morphological and Digital-Assisted Analysis for BCL6 Endometrial Expression in Women with Endometriosis

BCL6 (B-cell lymphoma 6) is a proto-oncogene and transcriptional repressor initially described as being involved in B-cell lymphoma. Recently, this factor has been identified as a promising tissue biomarker which could be used to diagnose women affected by endometriosis. Previous studies used HSCORE for BCL6 staining quantification in the endometrium. However, this semi-quantitative technique of analysis has some limitations, including a lack of objectivity, robustness, and reproducibility that may lead to intra- and inter-observer variability. Our main goal was to develop an original computer-assisted method to quantify BCL6 staining from whole-slide images reliably. In order to test the efficiency of our new digital method of quantification, we compared endometrial BCL6 expression between fertile and infertile women without or with different stages of endometriosis by using the widely used HSCORE analysis and our new automatic digital image analysis. We find a higher expression of BCL6 in the endometrium of infertile women with endometriosis and women with stage IV endometriosis. Furthermore, we demonstrate a significant correlation between the two types of independent measurements, indicating the robustness of results and also the reliability of our computer-assisted method for BCL6 quantification. In conclusion, our work, by using this original computer-assisted method, enables BCL6 quantification more objectively, reliably, robustly, and promptly compared to HSCORE analysis.

Endometrial stromal PRMT5 plays a crucial role in decidualization by regulating NF-κB signaling in endometriosis

Decidualization is a prerequisite for successful embryo implantation, in which elongated fibroblast-like endometrial stromal cells differentiate into more rounded decidual cells. Accumulating evidence has stressed the important role of the defective eutopic endometrium in infertility in endometriosis patients. However, the role of arginine methylation in the process of physiological decidualization and pathological decidualization defects is not clear. Here, we observed that the expression level of PRMT5, the main type II PRMT, was decreased in the endometrium of endometriosis patients, predominantly in stromal cells. Compared with the undecidualized state, PRMT5 was increased in the stromal cells of normal secretory endometrium in humans and in the decidua of normal pregnant mice or mice with artificially induced decidualization. The inhibition of PRMT5 resulted in a significant decrease in uterine weight and decidualization-related regulator expression, including FOXO1, HOXA10 and WNT4, in mice and IGFBP1 and prolactin levels in human endometrial stromal cells. Transcriptome analysis showed that decreased PRMT5 activity led to NF-κB signaling activation by inducing p65 translocation to the nucleus, which was also observed in endometriosis patients. Finally, overexpression of PRMT5 rescued the defective expression of IGFBP1 and prolactin in primary endometrial stromal cells from endometriosis patients. Our results indicate that promotion of PRMT5 may provide novel therapeutic strategies for the treatment of decidualization defects in infertile women, such as those with endometriosis.

Predictive Value of Basal Serum Progesterone for Successful IVF in Endometriosis Patients: The Need for a Personalized Approach

The data regarding the role of progesterone (P4) in reproductive events of endometriosis patients are limited. This prospective study aimed to examine the predictive value of basal P4 serum levels for successful in vitro fertilization (IVF) in patients with primary infertility and endometriosis. The study included 73 patients divided according to endometriosis treatment (surgery vs. control—no treatment). The general data, basal hormonal status, and pregnancy rates were determined for every patient. Clinical pregnancy was achieved in 40.3% of patients, and more often in patients treated for endometriosis before IVF. The regression analysis showed that higher basal P4 serum levels were associated with achieving pregnancy through IVF. When regression was adjusted for the patient and IVF characteristics, higher basal P4 serum levels were associated with pregnancy achievement in both groups of women, along with the basal serum levels of FSH, LH, and AMH; EFI score; and stimulation protocol. The ROC analysis showed that the basal P4 serum level for successful IVF should be ≥0.7ng/mL. The basal P4 serum level cut-off for IVF success in endometriosis patients was determined for the first time. Constructed models for IVF success prediction emphasize the importance of determining the basal P4 serum levels for the personalized treatment of endometriosis-related infertility.

TOP2A deficit-induced abnormal decidualization leads to recurrent implantation failure via the NF-κB signaling pathway

BACKGROUND

Successful implantation is a complex process that is influenced by embryo quality, endometrial receptivity, immune factors, and the specific type of in vitro fertilization protocol used. DNA topoisomerase IIα (TOP2A) is a well-known protein involved in cell proliferation; however, its expression and effect on the endometrium in recurrent implantation failure (RIF) have not been fully elucidated.

METHODS

The human endometrial tissues of healthy controls and patients with RIF were collected. A proteomic analysis was performed to evaluate the differentially expressed proteins between the RIF group and the fertile control group. The expression patterns of TOP2A in the human preimplantation endometrium of the patients with RIF were determined by immunohistochemical staining, Western blotting and qRT-PCR. TOP2A knockdown (sh-TOP2A) T-HESCs were generated using lentiviruses. The expression of TOP2A in T-HESCs was manipulated to investigate its role in decidualization. The TOP2A-related changes in decidualization were screened by mRNA sequencing in decidualized TOP2A knockdown and control T-HESCs and then confirmed by Western blotting and immunofluorescence staining. TOP2A-deficient mice were generated by injection of TOP2A-interfering adenovirus on GD2.5 and GD3.5.

RESULTS

We performed a proteomic analysis of endometrial tissues to investigate the potential pathogenesis of RIF by comparing the patients with RIF and the matched controls and found that TOP2A might be a key protein in RIF. TOP2A is ubiquitously expressed in both stromal and glandular epithelial cells of the endometrium. The data indicate that TOP2A expression is significantly lower in the mid-secretory endometrium of women with RIF. TOP2A expression was downregulated under stimulation by 8-bromo-cAMP and MPA. Ablation of TOP2A resulted in upregulated expression of decidual biomarkers and morphological changes in the cells. Mechanistic analysis revealed that TOP2A regulates the NF-κB signaling pathway in decidualized T-HESCs. The TOP2A-deficient mice exhibited lower fetal weights.

CONCLUSIONS

Our findings revealed that abnormal expression of TOP2A affects decidualization and changes the "window of implantation", leading to RIF. TOP2A participates in the processes of decidualization and embryo implantation, functioning at least in part through the NF-κB pathway. Regulating the expression of TOP2A in the endometrium may become a new strategy for the prevention and treatment of RIF.

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.

Endometriosis and oocyte quality: an analysis of 13 614 donor oocyte recipient and autologous IVF cycles

STUDY QUESTION

Does endometriosis affect live birth following donor oocyte recipient versus autologous IVF?

SUMMARY ANSWER

There was no significant difference in the live birth rate (LBR) in women with endometriosis undergoing donor oocyte recipient cycles versus autologous IVF cycles.

WHAT IS KNOWN ALREADY

For infertile women with endometriosis, IVF is often considered as a treatment option. Lower implantation and pregnancy rates have been observed following IVF in women with endometriosis. It has been debated whether the lower pregnancy rate is due to the effect on oocyte quality or the endometrium, thus affecting implantation. To delineate whether endometriosis affects oocyte quality or the endometrium, we planned a study, using a donor oocyte recipient model, where the recipients were women diagnosed with endometriosis and compared their outcomes with women who underwent autologous IVF, who had also been diagnosed with endometriosis.

STUDY DESIGN, SIZE, DURATION

Human Fertilization and Embryology Authority (HFEA) anonymized data from 1996 to 2016 were analyzed. This comprised of a total of 758 donor oocyte recipients, where the recipients were women diagnosed with endometriosis, and 12 856 autologous IVF cycles where the women were diagnosed with endometriosis as the sole cause of infertility.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data on all women with endometriosis undergoing donor oocyte recipient and autologous IVF cycles were analyzed to compare live birth outcomes. Logistic regression analysis was performed adjusting for number of previous IVF cycles, previous live birth, period of treatment, day of embryo transfer, number of embryos transferred and fresh or frozen embryo transfer cycle.

MAIN RESULTS AND THE ROLE OF CHANCE

There was no significant difference in the LBR in women with endometriosis undergoing donor oocyte recipient fresh embryo transfer cycles compared to women undergoing autologous IVF fresh embryo transfer cycles (31.6% vs 31.0%; odds ratio (OR) 1.03, 99.5% CI 0.79–1.35). After adjusting for confounders, there was no significant difference in LBR in women with endometriosis undergoing donor oocyte recipient fresh embryo transfer cycles versus autologous fresh embryo transfer cycles (adjusted OR (aOR) 1.05, 99.5% CI 0.79–1.41).

There was no significant difference in the LBR in women with endometriosis undergoing donor oocyte recipient frozen embryo transfer cycles compared to women undergoing autologous frozen embryo transfer cycles (19.6% vs 24.0%; OR 0.77, 99.5% CI 0.47–1.25). After adjusting for potential confounders, there was no significant difference in the LBR in women undergoing donor oocyte recipient frozen embryo transfer cycles compared with autologous frozen embryo transfer cycles (aOR 0.85, 99.5% CI 0.51–1.41).

LIMITATIONS, REASONS FOR CAUTION

Although the analysis was adjusted for potential confounders, there was no information on the extent and classification of endometriosis as well as oocyte number. Furthermore, adenomyosis is thought to co-exist in women with endometriosis and may have independent pathophysiological mechanisms affecting fertility, for which there was no information.

WIDER IMPLICATIONS OF THE FINDINGS

The study shows no difference in LBR between donor oocyte recipient cycles in which all recipients had endometriosis compared to autologous IVF cycles in women with endometriosis. Therefore, this study finding suggests that there may be a minimal or no effect of oocyte quality on IVF outcomes in women with endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was obtained. M.S.K. is an associate editor with Human Reproduction Open. He was not involved in the editorial or peer review process for the manuscript.

TRIAL REGISTRATION NUMBER

N/A.

Endometriosis: A Disease with Few Direct Treatment Options

Endometriosis is a gynecological condition characterized by the growth of endometrium-like tissues inside and outside the pelvic cavity. The evolution of the disease can lead to infertility in addition to high treatment costs. Currently, available medications are only effective in treating endometriosis-related pain; however, it is not a targeted treatment. The objective of this work is to review the characteristics of the disease, the diagnostic means and treatments available, as well as to discuss new therapeutic options.

Hormonal treatments for endometriosis: The endocrine background

Endometriosis is a benign uterine disorder characterized by menstrual pain and infertility, deeply affecting women's health. It is a chronic disease and requires a long term management. Hormonal drugs are currently the most used for the medical treatment and are based on the endocrine pathogenetic aspects. Estrogen-dependency and progesterone-resistance are the key events which cause the ectopic implantation of endometrial cells, decreasing apoptosis and increasing oxidative stress, inflammation and neuroangiogenesis. Endometriotic cells express AMH, TGF-related growth factors (inhibin, activin, follistatin) CRH and stress related peptides. Endocrine and inflammatory changes explain pain and infertility, and the systemic comorbidities described in these patients, such as autoimmune (thyroiditis, arthritis, allergies), inflammatory (gastrointestinal/urinary diseases) and mental health disorders.The hormonal treatment of endometriosis aims to block of menstruation through an inhibition of hypothalamus-pituitary-ovary axis or by causing a pseudodecidualization with consequent amenorrhea, impairing the progression of endometriotic implants. GnRH agonists and antagonists are effective on endometriosis by acting on pituitary-ovarian function. Progestins are mostly used for long term treatments (dienogest, NETA, MPA) and act on multiple sites of action. Combined oral contraceptives are also used for reducing endometriosis symptoms by inhibiting ovarian function. Clinical trials are currently going on selective progesterone receptor modulators, selective estrogen receptor modulators and aromatase inhibitors. Nowadays, all these hormonal drugs are considered the first-line treatment for women with endometriosis to improve their symptoms, to postpone surgery or to prevent post-surgical disease recurrence. This review aims to provide a comprehensive state-of-the-art on the current and future hormonal treatments for endometriosis, exploring the endocrine background of the disease.