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Ferroptosis is a novel type of programmed cell death dependent on iron and characterized by the accumulation of lipid peroxides in cells and is closely related to various diseases. Female infertility is a global health concern, which is associated with a variety of factors. The etiology remains unknown in many women with infertility. With further investigation into the pathogenesis of infertility, a growing number of studies have demonstrated the close connections between infertility and ferroptosis. Through a literature review, it is found that ferroptosis is closely involved in endometriosis- and polycystic ovarian syndrome (PCOS)-associated infertility and tubal factor infertility. Iron overload increases the resistance to ferroptosis, and ferroptosis in some cells accelerates endometrial lesion growth. Moreover, iron overload may be hazardous to oocytes. This review may shed some light on the diagnosis and treatment of female infertility., (© 2024. The Author(s).)

Infertility is recognized globally as a social disease and a growing medical condition, posing a significant challenge to modern reproductive health. Endometriosis, the third-most frequent gynecologic disorder, is one of the most common and intricate conditions that can lead to female infertility. Despite extensive research, the etiology, malignant transformation, and biological therapy of endometriosis remain unknown. Blood and follicular fluid are two matrices that have been carefully studied and can provide insights into women's health. These matrices are clinically significant because they contain metabolites closely associated with women's illness stage and reproductive outcomes. Nowadays, the application of metabolomic analysis in biological matrices may be able to predict the outcome of assisted reproductive technologies with greater precision. From a molecular viewpoint on reproductive health, we evaluate and compare the utilization of human follicular fluid and blood as matrices in analysis for diagnostic and assisted reproductive technology (ART) predictors of success for endometriosis patients. In the follicular fluid (FF), plasma, and serum of endometriosis-affected women, researchers identified dysregulations of oxidative stress, upregulation of several immune factors, and aberrations in energy metabolic pathways. The altered signatures negatively correlate with the overall oocyte and embryo quality and fertilization rate.

Female infertility constitutes a growing health problem in developing countries and could be associated with several possible causes including reproductive disorders, congenital malformations, infections and hormonal dysfunction. Nonetheless, a series of additional factors can also negatively impact female fertility and are represented by chronic exposure to environmental pollutants, stress, unhealthy lifestyle choices such as cigarette smoking and, among others, obesity. Excess weight is associated with several chronic diseases, and growing evidence demonstrates that it can compromise reproductive physiology due to its influence on endometrial gene expression and receptivity. Thus, the current review of the literature mainly focused on how obesity can impair uterine receptivity, mostly from a molecular point of view throughout the window of implantation (WOI) period at an endometrial level. It was also highlighted that an obesity-related increase in adipose tissue may lead to a modulation in the expression of multiple pathways, which could cause a hostile endometrial environment with a consequent negative impact on the uterine receptivity and the establishment of pregnancy. Thanks to the use of the endometrial receptivity assay (ERA), a specific microarray that studies the expression of a series of genes, it is now possible to evaluate the endometrial status of patients with infertility problems in a more detailed manner. Moreover, female fertility and endometrial receptivity could be affected by endometriosis, a chronic benign gynecological disease, whose cause-and-effect relationship to obesity is still uncertain. Therefore, further investigations would be required to better elucidate these mechanisms that govern embryo implantation and could be potentially useful for the generation of new strategies to overcome implantation failure and improve the pregnancy rates in obese women.

Endometriosis in half of affected women is closely related to problems with fertility. Endometriosis-associated infertility is caused by a wide range of abnormalities affecting the female reproductive tract, from oocyte quality impairment to disturbances in the eutopic endometrium or mechanical abnormalities resulting from disease progression. Since supportive antioxidant therapies, in addition to surgical treatment or assisted reproductive techniques (ARTs), have overall been proven to be effective tools in endometriosis management, the objective of our review was to analyze the role of antioxidant substances, including vitamins, micronutrients, N-acetylcysteine (NAC), curcumin, melatonin, and resveratrol, in endometriosis-related infertility. Most of these substances have been proven to alleviate the systemic oxidant predominance, which has been expressed through decreased oxidative stress (OS) markers and enhanced antioxidative defense. In addition, we demonstrated that the predominant effect of the aforementioned substances is the inhibition of the development of endometriotic lesions as well as the suppression of pro-inflammatory molecules. Although we can undoubtedly conclude that antioxidants are beneficial in fertility support, further studies explaining the detailed pathways of their action are needed.

Objective: The objective of this research is to investigate the association between the concentrations of soluble human leukocyte G antigen (sHLA-G) in the follicular fluid (FF) in infertile patients with peritoneal endometriosis submitted to in vitro fertilization., Methods: We performed a cross-sectional study, including ninety-six women undergoing in vitro fertilization (IVF) ageing ≤ 40 years. Infertile patients were classified into two groups: with endometriosis diagnosed by laparoscopy and without endometriosis due to tubal factor. ELISA measured soluble HLA-G in the FF of a pool of punctured (more than 17mm) follicles from women with endometriosis and without endometriosis who were subjected to ovulation induction for IVF. Embryos obtained after fertilization were classified according to the graduated embryo score (GES)., Results: Groups were comparables in terms of age, the number of follicles, AMH, FSH and all included reproductive outcomes. There was no association between sHLA-G concentrations and the average score of the generated embryos (p>0.05). Measurement of sHLA-G in the follicle fluid in women with endometriosis and without endometriosis (tubal factor) showed no significant difference (p>0.05). We also compared sHLA-G per follicle and per embryo, which were not different between both groups (p>0.05)., Conclusions: Patients with peritoneal endometriosis submitted to IVF did not demonstrate an altered sHLA-G in the follicular fluid compared to the follicular fluid sHLA-G concentration in tubal factor patients. Also, this molecule was not linked to any other reproductive outcome.

Metabolomics offers new methods to identify biomarkers for oocyte and embryo quality, and for a better understanding of the physiopathology of infertility. This review investigated the latest findings regarding metabolome-derived biomarkers in follicular fluid of women with the most common types of infertility, and the potential impact on reproductive medicine outcomes. PubMed was searched for publications on metabolomics and human follicular fluid, and key biomarkers, kinetics and relationships with infertility diseases were identified. A reduced concentration of glucose and increased concentrations of lactate and pyruvate were found in follicular fluid of patients with endometriosis and diminished ovarian reserve, and the opposite was found in patients with polycystic ovary syndrome. These signatures may lead to the hypothesis of changed metabolite concentrations in patients with endometriosis and diminished ovarian reserve, and a metabolic pathway alteration with decreased aerobic glycolysis in patients with polycystic ovary syndrome. However, the pattern found in patients with endometriosis and low responders may also be expected in follicular fluid of fertile women. Larger studies are needed to confirm the results. An international database may help to highlight follicular fluid biomarkers in order to improve the selection of cryopreserved oocytes, and to enrich culture medium to restore normal metabolism and improve reproductive treatment outcomes., (Copyright © 2023 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Endometriosis (EMT), a common benign gynecological disease, is a leading cause of infertility in women. EMT affects female fertility in various aspects. However, the underlying mechanisms have not been fully elucidated. Mitochondria are known as the "powerhouse" of a cell. They play pivotal roles in the physiological processes of cellular energy metabolism, calcium homeostasis, oxidative stress, autophagy, the regulation of cell cycle, and cell death, and are involved in the pathophysiology of many diseases. Cellular mitochondria are highly dynamic, continuously undergoing cyclic fission and fusion to meet the demands of cellular activities. Balanced mitochondrial dynamics are critical for maintaining normal reproductive function in women. In addition, mitochondria are the major source of reactive oxygen species (ROS). Cell damage, cell death, and fibrosis mediated by the imbalance in the oxidative-antioxidant system in EMT patients lead to decreased oocyte quality and ovarian reserve. Currently, the treatment of EMT-associated infertility remains a challenging and controversial topic. We herein reviewed the latest findings on the role of mitochondrial dysfunction in EMT-associated infertility and the potential therapeutic targets., Competing Interests: 利益冲突　所有作者均声明不存在利益冲突, (© 2024《四川大学学报（医学版）》编辑部 版权所有Copyright ©2024 Editorial Office of Journal of Sichuan University (Medical Sciences).)

Introduction: Endometriosis (EM) is a multifactorial disease that affects 10 - 15% of women of reproductive age. Additionally, 30-50% of women with EM suffer from infertility. The mechanism of infertility caused by EM has not yet been consistently explained. In recent years, studies have shown a link between infertility associated with EM and changes in the reproductive tract microbiota., Methods: In this study, we involved 26 EM patients (8 cases of stage I-II and 18 cases of stage III-IV) and 31 control subjects who were tubal obstruction-related infertility (TORI). The samples from peritoneal fluid (PF) and uterine fluid (UF) were collected and sequenced by 16 S rRNA amplicon., Results: In the comparison of microbial diversity, we found no significant differences in the microbial diversity of PF and UF between patients with stage I-II EM and those with TORI. However, there was a significant difference in microbial diversity among patients with stage III-IV EM compared to the previous two groups. Lactobacillus decreased in PF of EM compared to the control group, while it increased in UF. In PF, the abundance of Pseudomonas, Enterococcus, Dubosiella and Klebsiella was significantly higher in patients with stage III-IV compared to TORI patients. And in UF, the main differences existed between stage I-II EM compared to the other two groups. The abundance of pontibacter, aquabacterium, Rikenellaceae and so on at the genus level was significantly enriched in the EM patients with stage I-II. In the analysis based on KEGG database, EM may affect the receptivity related pathways of the endometrium by influencing changes in the uterine microbiota., Conclusion: Our results indicated that as EM progresses, the microorganisms in UF and PF keep changing. These changes in the microbiota, as well as the resulting alternations in gene functional classification, may play an important role in the infertility associated with EM., (© 2024. The Author(s).)

Oxidative Stress (OS) relates to the pathophysiology of endometriosis by activation of the inflammation process in the ovary, abdomen, peritoneum and endometrium. Advanced Glycation end-products (AGEs) cause oxidative damage to the follicles of the ovary. This study aims to investigate the correlation of follicular fluid soluble receptor of AGEs (FF sRAGE) with fertility-related parameters in infertile women with endometriosis. From January 2012 to July 2015 twenty-four women diagnosed with mild to moderate endometriosis aged 28-38 years underwent assisted reproduction. sRAGE levels measured in FF were related to lifestyle factors, sociodemographic characteristics, gynaecological and obstetric parameters, hormonal status and fertilization. sRAGE was inversely associated with BMI (r = -0.503, p  = 0.012). No significant association of sRAGE with age ( p  = 0.714) or alcohol consumption ( p  = 0.882) was found. Pearson's r correlation coefficient revealed that sRAGE was positively associated with serum AMH (r = 0.518, p  = 0.009), FF AMH (r = 0.630, p  = 0.001), number of follicles >15mm (r = 0.601, p  = 0.002), total number of follicles aspirated (r = 0.698, p  < 0.001), total number of MII oocytes obtained, (r = 0.757, p  < 0.001) and the number of embryos with good embryo scoring (suitable for ET) (r = 0.522, p  = 0.009). It seems that measurement of FF RAGE might be a useful predictive marker for IVF success in infertile women with endometriosis undergoing assisted reproduction.

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., (© 2023. The Author(s), under exclusive licence to Society for Reproductive Investigation.)

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 m 6 A 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 m 6 A 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.

Objective: To evaluate interleukin (IL)-1β, IL-6, IL-8, and IL-12p70 levels in serum and peritoneal fluid in women related to infertility and pelvic pain., Methods: Eighty-seven women were diagnosed with endometriosis or cases related to infertility. IL-1β, IL-6, IL-8, and IL-12p70 levels in serum and peritoneal fluid were determined by enzyme-linked immunosorbent assay (ELISA). Pain assessment was evaluated by the Visual Analog Scale (VAS) score., Results: Serum IL-6 and IL-12p70 levels increased in women with endometriosis compared to the control group. Serum and peritoneal IL-8 and IL-12p70 levels correlated with VAS scores in infertile women. A positive correlation was also found between peritoneal IL-1β and IL-6 with VAS score. A significant difference in peritoneal IL-1β levels was associated with menstrual pelvic pain, while peritoneal IL-8 levels were related to dyspareunia, menstrual, and post-menstrual pelvic pain in infertile women., Conclusions: An association of IL-8 and IL-12p70 levels were related to pain in endometriosis, as well as a relationship between cytokine expression and VAS score. Further studies should be addressed to investigate the precise mechanism of cytokine-related pain in endometriosis., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Problem: Endometriosis patients undergoing in vitro fertilization-embryo transfer (IVF-ET) treatment suffer from poor oocyte quality, a reduced likelihood of the fertilization rate, and low embryo quality. The dysregulation of immune cells and cytokine profiles in the follicular fluid (FF) may play an important role in the competence of the oocyte and the development of the embryo, but the mechanism remains largely unknown., Method of Study: A total of 40 proved advanced staged endometriosis patients were enrolled in this study. The pregnancy results were followed until all the embryos collected by the first oocyte retrieval cycle were used up. The immune cells subtypes in FF and serum collected on the day of oocyte retrieval were detected by flow cytometry and 27 cytokines were determined using the Bio-Plex Pro Human Cytokine 27-Plex Immunoassay. The specific effect of cytokine on the gene expression of human granulosa cells was determined by RT-qPCR., Results: The fertilization rate and the cumulative live birth rate were significantly lower in the endometriosis group. The ratio of CD4 + /CD8 + T cells in FF was significantly lower, while the level of IP-10, RANTES and G-CSF were statistically higher in the endometriosis group. The level of IP-10 correlated with the IVF outcome. Moreover, treated by IP-10, the mRNA level of FSHR and CYP19A1 the human granulosa cells were downregulated in vitro., Conclusion: These results suggest that alterations of the lymphocyte subsets and cytokines in women with advanced endometriosis may have an impact on the oocyte development and resulting in poorer IVF outcomes., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Increasing evidences showed that ovulatory dysfunction, possibly caused by luteinized unruptured follicular follicle syndrome (LUFS), is one of the reasons for endometriosis-related infertility. The present study was conducted to explore the potential effect of elevated progesterone in follicular fluid (FF) on ovulation in endometriosis. A prospective study including 50 ovarian endometriosis patients and 50 control patients with matched pairs design was conducted with alterations in FF and peritoneal fluid (PF) components identified by metabolomics analyses and differentially expressed genes in granulosa cells (GCs) identified by transcriptome analysis. Patients with endometriosis exhibited a significantly higher progesterone level in serum, FF, and PF. Granulosa cells from endometriosis patients revealed decreased expression of HPGD, COX-2, and suppressed NF-ĸB signaling. Similarly, progesterone treatment in vitro downregulated HPGD and COX2 expression and suppressed NF-ĸB signaling in granulosa tumor-like cell line KGN (Bena Culture Collection, China) and primarily cultured GCs, as manifested by decreased expressions of IL1R1, IRAK3, reduced pIĸBα/IĸBα ratio, and nucleus translocation of p65. On the contrary, TNF-α treatment increased expression of IL1R1, IRAK3, pIĸBα, p65, and HPGD in GCs. One potential p65 binding site was identified in the promoter region of HPGD by chromatin immunoprecipitation. In conclusion, we found that intrafollicular progesterone might downregulate HPGD and COX-2 in GCs via suppressing the NF-ĸB signaling pathway, shedding light on the mechanism underlying the endometriosis-related ovulatory dysfunction., (© The Author(s) 2023. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Endometriosis is the most common cause of infertility. Endometrial receptivity has been suggested to contribute to infertility and poor reproductive outcomes in affected women. Even though experimental and clinical data suggest that the endometrium differs in women with endometriosis, the pathogenesis of impaired endometrial receptivity remains incomplete. Therefore, this review summarizes the potential mechanisms that affect endometrial function and contribute to implantation failure. Contemporary data regarding hormone imbalance, inflammation, and immunoregulatory dysfunction will be reviewed here. In addition, genetic, epigenetic, glycosylation, metabolism and microRNA in endometriosis-related infertility/subfertility will be summarized. We provide a brief discussion and perspectives on their future clinical implications in the diagnosis and therapy to improve endometrial function in affected women.

The mechanism by which endometriosis, a common gynecological disease characterized by chronic pelvic pain and infertility, causes infertility remains elusive. Luteinized unruptured follicle syndrome, the most common type of ovulatory dysfunction, is a cause of endometriosis-associated infertility involving reduced numbers of retrieved and mature oocytes. Ovulation is controlled by luteinizing hormone and paracrine signals produced within the follicle microenvironment. Generally, interleukin (IL)-1β is elevated in endometriosis follicular fluid, whereby it amplifies ovulation signals by activating extracellular-regulated kinase 1/2 and CCAAT/enhancer binding protein β pathways. However, this amplification of ovulation by IL-1β does not occur in patients with endometriosis. To illuminate the mechanism of ovulatory dysfunction in endometriosis, we analyzed the effect of oxidative stress and IL-1β expression on endometriosis follicles. We found that oxidative stress decreased EZH2 expression and reduced H3K27Me3 levels in endometriosis ovarian granulosa cells (GCs). Selective Ezh2 depletion in mice ovarian GCs reduced fertility by disturbing cumulus-oocyte complex expansion and reducing epidermal growth factor-like factor expression. Gene expression and H3K27Me3 ChIP-sequencing (ChIP-Seq) of GCs revealed IL-1 receptor 2 (IL-1R2), a high-affinity IL-1β-receptor that suppresses IL-1β-mediated inflammatory cascades during ovulation, as a crucial target gene of the EZH2-H3K27Me3 axis. Moreover, IL-1β addition did not restore ovulation upon Ezh2 knockdown, indicating a vital function of IL-1R2 in endometriosis. Thus, our findings show that reducing EZH2 and H3K27Me3 in GCs suppressed ovulatory signals by increasing IL-1R2 expression, which may ultimately contribute to endometriosis-associated infertility., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Endocrine Society.)

This study aimed to explore common molecular changes in the infertile endometrium from women with and without endometriosis (EM). By analyzing the dataset GSE120103 from Gene Expression Omnibus, a total of 3252 shared differentially expressed genes were identified between ovarian EM in infertile vs. fertile endometrium and EM-free infertile vs. fertile endometrium. In addition, the gene annotation and pathway analysis of the shared differentially expressed genes with the same expression trend indicated that the pathway 'MHC class II antigen presentation' and five candidate genes: HLA-DRA, HLA-DRB1, HLA-DRB3, HLA-DPA1, HLA-DPB1 were both down-regulated in infertile endometrium with or without EM. Logistic regression showed that HLA-DRA might be an independent predictor of the infertile status of the endometrium. Single sample gene set enrichment analysis (ssGSEA) showed that some classic antigen-presenting cells: macrophages type 1, macrophages type 2, and mature dendritic cells were significantly down-regulated in infertile endometrium with or without EM, whose enrichment correlated positively with the expression of candidate HLA molecules. Hence, the down-regulation of HLA-DRs and HLA-DPs reflecting the deficiency of antigen-presenting cells in endometrium might serve as a common biomarker for diagnosing endometrium-associated infertility in women with and without endometriosis.

The prevalence of endometriosis is approximately 10% in women of reproductive age, and 30-50% of women with endometriosis are infertile. Metformin has been reported to inhibit the growth of ectopic lesions in endometriosis. However, its effect on the eutopic endometrium of endometriosis is unknown. This study aimed to identify whether metformin affects endometrial receptivity in infertile women with minimal/mild endometriosis. We enrolled 10 infertile women who were diagnosed with minimal/mild endometriosis through laparoscopy. Paired endometrial tissues of the secretory phase from participants were collected during surgery and after 2 months of metformin treatment (n = 5) or no medical treatment (n = 5). Protein expression profiles of the paired endometrium were detected by proteomics and compared using the self-control method (2 months later vs. in surgery). Proteomics data revealed six proteins associated with endometrial receptivity among the significantly upregulated proteins after metformin treatment (fold change > 1.5, P < 0.05). Insulin-like growth factor binding protein 7 (IGFBP-7) showed the most robust increase in these six endometrial receptivity-related proteins (fold change: 8.668, P < 0.05), while there was no significant change in the controls (fold change: 1.906, P > 0.05). The upregulation of IGFBP-7 has been validated through target proteomics, immunohistochemistry, and further demonstrated in endometriosis mouse models induced by autotransplantation. This study revealed that metformin upregulated the expression of IGFBP-7 in the endometrium of human and mouse models of endometriosis. Metformin potentially affects endometrial receptivity of minimal/mild endometriosis by improving the expression of the endometrial receptivity marker IGFBP-7., (© 2022. Society for Reproductive Investigation.)

Objective: Endometriosis is associated with infertility, even without an anatomical abnormality. Furthermore, the peritoneal (mild) phenotype of this disease is the most prevalent and linked to infertility. The present study aimed to investigate the p63 gene and protein expression in granulosa cells from pre-ovulatory follicles in patients with endometriosis and infertility submitted to in vitro fertilization., Methods: Twenty-eight patients participated in the study and were divided into two groups according to the presence or absence of endometriosis. The p63 gene-expression levels assessment was performed by real-time PCR (qPCR) using the TaqMan assay, and we used immunofluorescence to check the p63 protein expression after IVF., Results: There was no significant difference between the groups regarding age, hormonal levels, oocyte standards, and p63 gene expression. The control group showed an RQ of 1.000 (0.431 to 2.323) and the study group showed an RQ of 0.725 (0.249 to 2.105), p>0.05. Both groups showed a weak expression of the p63 gene (p>0.05)., Conclusions: This study described that endometriosis may not affect the p63 gene expression. Moreover, after follicular recruitment and growth, we found a weak expression of this protein, suggesting it is not part of oocyte maturation and development control.

Objective: (1) To characterize the cytokine expression profiles of endometriosis related infertile women in comparison to fertile women with endometriosis; (2) to investigate the correlation of the cytokine levels from different tissues., Methods: 100 stage IV endometriosis patients were recruited and grouped by infertility status ( n  = 50, separately). Concentrations of TNF-α, TGF-β1, IL-10, and IL-17A from the serum, peritoneal fluid (PF), eutopic, and ectopic endometrium samples were measured., Results: (1) In the infertile group, the concentrations of IL-10 within serum, PF and eutopic endometrium were all significantly higher ( p  = .022 and <.01, .013, respectively), the levels of TGF-β1 in serum and eutopic endometrium samples were both higher ( p  = .025 and p  < .01), the levels of IL-17A in the PF, eutopic, and ectopic endometrium were all lower ( p  < .01, all). (2) Significant positive correlation was observed between IL-17A from PF and the ectopic endometrium ( p  = .014), IL-17A from PF and eutopic endometrium ( p  < .01). The PF IL-10 levels positively correlated with those in the serum ( p  = .007)., Conclusions: This is the first study comparing the levels of cytokines within four different tissues of endometriosis women with or without infertility. The study revealed that endometriosis-related infertile women possess significant differences in cytokine levels in comparison to fertile women with endometriosis. The levels of inflammatory factors from different tissues had certain positive correlations. Infertility may indicate the progress of the disease.

Endometriosis is the cause of infertility. The eutopic endometrium of women with endometriosis showed an aberrant expression pattern of multitude genes. The role of TET1 protein in the pathogenesis of endometriosis and related infertility is not sufficiently known. Further, knowledge on TET1 transcriptional control still remains incomplete. The aim of the study was assessment of TET1 gene expression, DNA methylation and H3K27me3 level of its promoter region in eutopic endometrium of women with endometriosis and infertility. The study included 44 infertile patients with endometriosis (IWE) and 77 infertile (IW) and fertile (FW) patients without endometriosis. The research material was eutopic endometrium. The TET1 mRNA level was analyzed by qPCR. Western blot was used to evaluate the level of TET1 protein. The level of DNA methylation and H3K27me3 level of TET1 gene's promoter region were assessed using HRM and ChIP qPCR, respectively. The level of TET1 expression (TET1 mRNA; TET1 protein level) was lower in IWE during the implantation window (p < 0.001; p = 0.0329). The level of TET1 DNA methylation was higher in the secretory endometrium in mild and advanced IWE (p < 0.004; p < 0.008). H3K27me3 level did not differ between the study groups. The diminished expression of TET1 gene during the secretory phase, may account for the aberrant process of embryonic implantation in infertile endometriosis patients. DNA hypermethylation of TET1 gene is a potential relevant regulator of its expression. H3K27me3 occupancy does not affect the expression of TET1 gene in our study group., (Copyright © 2022 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

A growing body of work suggests epigenetic dysregulation contributes to endometriosis pathophysiology and female infertility. The chromatin remodeling complex subunit AT-rich interaction domain 1A (ARID1A) must be properly expressed to maintain normal uterine function. Endometrial epithelial ARID1A is indispensable for pregnancy establishment in mice through regulation of endometrial gland function; however, ARID1A expression is decreased in infertile women with endometriosis. We hypothesized that ARID1A performs critical operations in the endometrial epithelium necessary for fertility besides maintaining gland function. To identify alterations in uterine gene expression resulting from loss of epithelial ARID1A, we performed RNA-sequencing analysis on pre-implantation uteri from Ltf iCre/+ Arid1a f/f and control mice. Differential expression analysis identified 4181 differentially expressed genes enriched for immune-related ingenuity canonical pathways including agranulocyte adhesion and diapedesis and natural killer cell signaling. RT-qPCR confirmed an increase in pro-inflammatory cytokine and macrophage-related gene expression but a decrease in natural killer cell signaling. Immunostaining confirmed a uterus-specific increase in macrophage infiltration. Flow cytometry delineated an increase in inflammatory macrophages and a decrease in uterine dendritic cells in Ltf iCre/+ Arid1a f/f uteri. These findings demonstrate a role for endometrial epithelial ARID1A in suppressing inflammation and maintaining uterine immune homeostasis, which are required for successful pregnancy and gynecological health.

Endometriosis is a chronic inflammatory disorder that is highly associated with infertility. This association seems to be related to oocyte impairment, mainly in the initial stages of endometriosis (minimal and mild), where no distortions or adhesions are present. Nonetheless, invasive oocyte analyses are not routinely feasible; thus, indirect assessment of oocyte quality is highly desirable, and, in this context, cumulus cells (CCs) may be more suitable targets of analysis. CCs are crucial in oocyte development and could be used as an index of oocyte quality. Therefore, this prospective case-control study aimed to shed light on the infertility mechanisms of endometriosis I/II by analyzing the CCs' mRNA transcription profile (women with endometriosis I/II, n = 9) compared to controls (women with tubal abnormalities or male factor, n = 9). The transcriptomic analyses of CCs from patients with minimal and mild endometriosis revealed 26 differentially expressed genes compared to the controls. The enrichment analysis evidenced some altered molecular processes: Cytokine-cytokine receptor interactions, Chemokine signaling, TNF signaling, NOD-like receptor signaling, NF-kappa B signaling, and inflammatory response. With the exception of CXCL12, all enriched genes were downregulated in CCs from patients with endometriosis. These findings provide a significant achievement in the field of reproductive biology, directing future studies to discover biomarkers of oocyte quality in endometriosis., (© 2022. The Author(s).)

Endometriosis is a common estrogen-dependent chronic inflammatory disease that leads to infertility in women of reproductive age. Perhaps infertility reflects the reduced expression of integrin αvβ3 and HOXA10 in endometriosis. Previous studies have shown that administration of letrozole, a non-steroidal aromatase inhibitor for cancer treatment, increased the clinical pregnancy rate in women with endometriosis, but the mechanisms remain to be determined. In this communication, a rat model of endometriosis was established. Animals were treated with letrozole at 2ug/kg of body weight, intragastric administration for 15 consecutive days. Letrozole increased the expression of αvβ3 and HOXA10 in the endometriosis model and endometrial receptivity. Abbreviations: WOI: window of implantation; RGD: Arg-Gly-Asp; HOX: homeobox; E2: estradiol; SPF: specific pathogen-free.

Female subfertility is highly associated with endometriosis. Endometrial progesterone resistance is suggested as a crucial element in the development of endometrial diseases. We report that MIG-6 is downregulated in the endometrium of infertile women with endometriosis and in a non-human primate model of endometriosis. We find ERBB2 overexpression in the endometrium of uterine-specific Mig-6 knockout mice (Pgr cre/+ Mig-6 f/f ; Mig-6 d/d ). To investigate the effect of ERBB2 targeting on endometrial progesterone resistance, fertility, and endometriosis, we introduce Erbb2 ablation in Mig-6 d/d mice (Mig-6 d/d Erbb2 d/d mice). The additional knockout of Erbb2 rescues all phenotypes seen in Mig-6 d/d mice. Transcriptomic analysis shows that genes differentially expressed in Mig-6 d/d mice revert to their normal expression in Mig-6 d/d Erbb2 d/d mice. Together, our results demonstrate that ERBB2 overexpression in endometrium with MIG-6 deficiency causes endometrial progesterone resistance and a nonreceptive endometrium in endometriosis-related infertility, and ERBB2 targeting reverses these effects., (© 2022. The Author(s).)

Objective: To evaluate whether endometrial molecular profiles distinguish subsets of patients according to clinical characteristics, and to infer dysregulated immune networks, by measuring cytokines, chemokines, and growth factors in endometrial biopsy specimens from a cohort of infertile women with a high incidence of endometriosis., Design: Prospective cohort study., Setting: Department of Gynecology at a university hospital., Patient(s): Patients undergoing laparoscopy for infertility assessment (n = 103)., Intervention(s): Endometrial biopsies were performed during surgery. Fertility outcome and clinical parameters were registered preoperatively and after 6 months., Main Outcome Measure(s): The concentrations of 48 factors in endometrial biopsy specimens were analyzed with respect to clinical status in univariate and multivariate frameworks., Result(s): The concentrations of 44 factors from endometrial tissues of 74 patients were suitable for analysis. Although the tissue concentrations of interleukin (IL)15, IL-7, and interferon γ-induced protein (IP)-10 were individually lower in patients with endometriosis than in those without endometriosis, the differences were not significant after multiple comparison. However, multivariate modeling incorporating covariation showed separation between subsets of endometriotic and nonendometriotic patients, based predominantly on IP-10, monocyte chemoattractant protein-1, IL-16, and IL-18; this result was independent of cycle and fertility status. Analysis restricted to endometrial tissues from the secretory phase separated endometriotic and nonendometriotic patients by a combination of IL-15, IP-10, monocyte chemoattractant protein-1, IL-16, and IL-18. This combination suggests a uterine natural killer cell defect. We found no significant correlations between endometrial cytokines and fertility outcome., Conclusion(s): A molecular signature in endometrial tissue was able to distinguish endometriotic from nonendometriotic patients, implicating uterine natural killer cells in endometriosis., (Copyright © 2021. Published by Elsevier Inc.)

Endometriosis is a common gynecological disease associated with infertility, and it represents an economic burden worldwide. However, the molecular mechanisms underlying endometriosis development have not yet been fully elucidated. Here, we aimed to identify reliable key genes and the related regulatory network that may be involved in endometriosis. Differentially expressed genes (DEGs) were identified through integrated analysis of four expression datasets of endometriosis from Gene Expression Omnibus. Gene functional analysis and protein-protein interaction network construction were performed to reveal the potential function of DEGs. Subsequently, candidate hub genes were defined and validated in GSE105764 dataset, and the associated regulatory networks were constructed. Additionally, GSE120103 dataset was applied to identify the differential expression between the infertile and fertile groups of patients with stage IV endometriosis. Finally, real-time quantitative polymerase chain reaction analysis was performed to identify the differential expression of hub genes in the collected clinical specimens. Robust rank aggregation integrated analysis determined 158 DEGs. Epithelial cell differentiation was the most significantly enriched biological process, and leukocyte transendothelial migration was the most significantly enriched pathway. Eight hub genes including CLDN3, CLDN5, CLDN7, CLDN11, HOXC8, HOXC6, HOXB6, and HOXB7 were identified, and most of these were validated as abnormally expressed genes in both the infertile group and patients with endometriosis. Transcriptional factors and microRNAs related to these genes were identified. Altogether, our integrated analysis identified critical gene signatures, involved pathways, and regulatory networks, which could provide clinically significant insights into the molecular mechanisms underlying endometriosis and its related infertility., (© 2021. Society for Reproductive Investigation.)

Evidence to date supports regulatory T cell (Treg) alterations in endometriosis; however, the relationship remains unclear, and Tregs have not previously been investigated with respect to infertility in endometriosis. This prospective cross-sectional cohort study details circulating and endometrial tissue-specific disturbances in Tregs and broader gated populations in women of reproductive age with and without endometriosis (n = 57 and 29, respectively) using flow cytometry and immunohistochemistry. Participants were characterised by menstrual cycle phase, r-ASRM endometriosis disease stage and fertility status.In the endometrium of women with endometriosis, endometrial Tregs and CD4+ lymphocyte proportions did not change between the proliferative and secretory phases, while in women without the disease, they significantly decreased (p = 0.045 and p = 0.039, respectively). In women with endometriosis, endometrial Tregs were lower than in women without endometriosis overall (p = 0.050 as a proportion of all CD45+ immune cells). We have shown for the first time that proportions of CD4+ lymphocytes (p = 0.021), overall lymphocytes (p = 0.034) and non-granulocytes (p = 0.027) were significantly decreased in the endometrium of women with moderate-severe (r-ASRM stages III and IV) compared to minimal-mild (r-ASRM stages I and II) endometriosis. During the secretory phase, circulating Treg proportions were significantly increased in infertile compared to fertile women (p = 0.049). This study confirms differences in endometrial Tregs in women with endometriosis, with blunting of normal menstrual cyclical variations, reduced proportions during the proliferative phase and disease stage-specific relationships., (© 2021. Society for Reproductive Investigation.)

Objective: To explore the mechanisms of follicular fluids (FFs) on granulose cell (GC) apoptosis in endometriosis-associated infertility., Materials and Methods: 60 infertile women were enrolled. The FFs from 30 endometriosis-associated infertility (EI) patients were collected and processed by ELISA hormone assay and proteomic profiling. The ovary GCs collected from 30 tubal-associated infertility (TI) patients were cultured in follicular fluids of endometriosis-associated infertility patients (EI-FFs), and the apoptosis mechanisms were explored by flow cytometry assay, real-time PCR, Western blotting, and protein-protein interaction (PPI) network analysis., Results: Our results showed that the expression of 22 specific proteins was significantly different in the FFs from EI and TI patients, and the level of testosterone and anti-Müllerian hormone was not obviously different between the two groups. EI-FFs could accelerate the apoptosis process of granulose cells of tubal-associated infertility patients (TI-GCs) by regulating the expression of 5 apoptosis-related proteins including BCL2, BAX, CASP3, CASP9, and TP53. The correlation of these 22 specific proteins and 5 apoptosis-related proteins was analyzed by PPI, and 5 protein biomarkers (INS, CXCL10, ICAM1, WIF1, and TNFRSF13C) and 5 signaling pathways (cytokine-cytokine receptor interaction, apoptosis, regulation of actin cytoskeleton, MAPK, and p53 signaling pathway) were predicted., Conclusion: This research clarified the effect and explored the mechanisms of EI-FFs on the apoptosis of TI-GCs and indicated the protein biomarkers and signaling pathways for further study., Competing Interests: The authors declared no potential conflicts of interests with respect to the authorship and/or publication of this article., (Copyright © 2021 Lu Chen et al.)

The diagnosis of endometriosis and fertility disorders is difficult; therefore, it is necessary to look for reliable biomarkers. Analysis of the molecular status of fibronectin as a key player in repair and wound healing processes, as well as in coagulation and fibrinolysis pathways, is justified. ELISA and SDS-agarose immunoblotting were applied to determine the fibronectin concentration and presence and occurrence of soluble FN-fibrin complexes in the blood plasma of women with endometriosis (n = 38), fertility disorders (n = 28) and the healthy group (n = 25). The concentration of fibronectin in the blood plasma of women with endometriosis (292.61 ± 96.17 mg/L) and fertility disorders (287.53 ± 122.68 mg/L) was significantly higher than in the normal group (226.55 ± 91.98 mg/L). The presence of FN-fibrin complexes of 750, 1000, 1300, 1600 and 1900 kDa in the plasma of women with endometriosis and fertility disorders was shown. The presence of FN-fibrin complexes with a molecular mass of more than 1300 kDa in women with endometriosis and infertility and the complete absence of these complexes in healthy women may indicate an increased and chronic activation of coagulation mechanisms in these patients. The presence of complexes of high molecular mass may be one of the biomarkers of fertility disorders in women.

About 40% of women with infertility and 70% of women with pelvic pain suffer from endometriosis. The pregnancy rate in women undergoing IVF with low endometrial integrin αvβ3 (LEI) expression is significantly lower compared to the women with high endometrial integrin αvβ3 (HEI). Mid-secretory eutopic endometrial biopsies were obtained from healthy controls (C; n=3), and women with HEI (n=4) and LEI (n=4) and endometriosis. Changes in gene expression were assessed using human gene arrays and DNA methylation data were derived using 385 K Two-Array Promoter Arrays. Transcriptional analysis revealed that LEI and C groups clustered separately with 396 differentially expressed genes (DEGs) (P<0.01: 275 up and 121 down) demonstrating that transcriptional and epigenetic changes are distinct in the LEI eutopic endometrium compared to the C and HEI group. In contrast, HEI vs C and HEI vs LEI comparisons only identified 83 and 45 DEGs, respectively. The methylation promoter array identified 1304 differentially methylated regions in the LEI vs C comparison. The overlap of gene and methylation array data identified 14 epigenetically dysregulated genes and quantitative RT-PCR analysis validated the transcriptomic findings. The analysis also revealed that aryl hydrocarbon receptor (AHR) was hypomethylated and significantly overexpressed in LEI samples compared to C. Further analysis validated that AHR transcript and protein expression are significantly (P<0.05) increased in LEI women compared to C. The increase in AHR, together with the altered methylation status of the 14 additional genes, may provide a diagnostic tool to identify the subset of women who have endometriosis-associated infertility., (© The Author(s) 2021. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Aim: Endometriosis is associated with infertility. The aim of this study was to examine the overall proteomic changes of eutopic endometrium in infertile women with endometriosis., Methods: Tandem mass tags combined with multidimensional liquid chromatography and mass spectrometry analyses were used to screen the proteomic profiles of eutopic endometrium from infertile patients with endometriosis (N = 4), compared with that from patients without endometriosis (N = 4). Quantitative proteomic analysis, functional categories and significant pathway analysis were investigated subsequently., Results: In total, 6.698 proteins were identified, among which 5,812 proteins were quantified. Compared with controls, proteomic analysis showed some differentially expressed proteins: 16 up-regulated proteins and 23 down-regulated proteins. Bioinformatics analysis indicated that differentially expressed proteins were involved in humoral immune response pathways, antimicrobial humoral response and regulation of nitric oxide biosynthetic process. Besides, our results showed that alpha-1-acid glycoprotein 2, complement factor B and zinc transporter Zip14 were important resources for investigating potential mechanism of infertility in infertile women with endometriosis., Conclusions: This study provided a reference proteome map of eutopic endometrium from infertile women with endometriosis. The long-term benefits of using those markers to stratify clinical treatment warrant further investigation., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Research Question: Is the transcriptome of cumulus cells of infertile women with advanced endometriosis (EIII/IV), with and without endometrioma, altered?, Design: In this prospective case-control study, next-generation RNA sequencing was used to compare the transcript profile of cumulus cells among infertile patients undergoing ovarian stimulation for intracytoplasmic sperm injection with EIII/IV, with (n = 9) and without endometrioma (n = 9), and controls (n = 9). An in-silico enrichment analysis was conducted to establish the possibly altered pathways in cumulus cells of patients with endometriosis., Results: Most of the differentially expressed genes (DEG) were found when cumulus cells from women with EIII/IV with endometrioma were compared with controls (DEG, n = 461). In women with EIII/IV without endometrioma, only 66 DEG were verified compared with controls. The enrichment analysis showed that some DEG in cumulus cells of endometriosis are involved in important pathways for the oocyte competence acquisition, such as oxidative phosphorylation, metabolism, mitochondrial function, acetylation and steroid biosynthesis. No DEG were found when cumulus cells from women with EIII/IV with and without endometrioma were compared., Conclusion: RNA sequencing results suggest that cumulus cells of infertile women with EIII/IV have an altered transcriptome, regardless of endometrioma. The present findings offer a better understanding of the genes and molecular mechanisms that may be involved in endometriosis-related infertility, mostly in the oocyte competence acquisition process., (Copyright © 2021 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Endometriosis (EMs) is a common cause for female infertility, leading to the need for in vitro fertilization (IVF). In clinics, we found the operative oocyte retrieval to be more or less difficult in women with EMs. We hypothesized that EMs may be involved in the insufficient cumulus expansion that partially explained the lower oocyte retrieval in EMs-related infertile women undergoing assisted reproductive technology (ART). To explore whether the insufficient cumulus expansion exists in EMs-related infertile women and whether there is a possible relationship between the insufficient cumulus expansion and the clinical phenomenon of difficulty in oocyte retrieval. Those infertile women undergoing IVF recorded in our database between January 2013 and October 2017 were included. The expression levels of cumulus expansion-related genes (HAS2/PTGS2/PTX3/TNFAIP6) in the cumulus cells (CCs) from 19 infertile women with EMs and 24 controls were analyzed by real-time PCR. After that, 635 women with EMs-associated infertility (the EMs group) and 4634 women with male factor-associated infertility (the control group) were included in the retrospective analysis. The clinical outcomes were compared between the two groups. The relative mRNA levels of cumulus expansion-related genes were significantly decreased in the CCs from those infertile women with EMs when compared to the control group (all p < 0.05), especially the expression of PTGS2. The mean oocyte retrieval rates (proportion of obtained oocytes in punctured follicles) were (76.33 ± 2.58)% and (71.80 ± 0.58)% (p < 0.01). The mean numbers of flushing times per follicle were 1.11 ± 0.65 and 3.86 ± 1.53 (p < 0.001). The lower expression of cumulus expansion-related genes in CCs suggests the insufficient cumulus expansion in EMs-related infertile women, which partially explains a possible mechanism related to poor oocyte retrieval.

Uric acid (UA) is the end metabolic product of purine metabolism. Early on, UA was considered to be a metabolite with a certain antioxidant capacity. As research has progressed, other properties of UA have been explored, and its association with many diseases has been found. The association between UA and kidney disease and cardiovascular disease is well established; however, there is still a paucity of reviews on the association between UA and the female reproductive system. An increasing number of epidemiological studies have shown elevated serum UA levels in patients with polycystic ovary syndrome (PCOS), endometriosis, etc. Additionally, serum UA can be used as a predictor of pregnancy complications and adverse foetal outcomes. An increasing number of animal experiments and clinical studies have revealed possible mechanisms related to the involvement of UA in certain female reproductive disorders: oxidative stress, chronic inflammation, mitochondrial dysfunction, etc. This article reviews the current mainstream mechanisms regarding the pathogenesis of UA and the role of UA in certain specific female reproductive disorders (direct involvement in the development of certain diseases or enhancement of other risk factors) in the hope of contributing to clinical prevention, diagnosis, treatment and improvement in prognosis.

Research Question: Is the profile of microRNA (miRNA) altered in cumulus cells of infertile women with early (EI/II) and advanced (EIII/IV) endometriosis?, Design: In this prospective case-control study, a miRNA profile including 754 targets was evaluated in samples of cumulus cells from infertile women with endometriosis (5 EI/II, 5 EIII/IV) and infertile controls (5, male and/or tubal factor) undergoing ovarian stimulation for intracytoplasmic sperm injection, using TaqMan® Array Human MicroRNA Cards A and B. The groups were compared with Kruskal-Wallis test, followed by Benjamini-Hochberg correction and Dunn's post hoc test. An in silico enrichment analysis was performed to list the possibly altered pathways in which the altered miRNA target genes are involved., Results: Only the miRNA miR-532-3p showed significant differences among the analysed groups, being down-regulated in the EIII/IV group compared with the infertile control group, as well as compared with the EI/II group. The enrichment analysis showed that some genes regulated by this miRNA are involved in important pathways for the acquisition of oocyte competence, such as the oxytocin, calcium, Wnt, FoxO, ErbB and Ras signalling pathways, as well as the oocyte meiosis pathway., Conclusion: The present findings bring new perspectives to understanding the follicular microenvironment of infertile women with different stages of endometriosis. It is suggested that the dysregulation of miR-532-3p may be a potential mechanism involved in the aetiopathogenesis of endometriosis-related infertility. Further studies are needed to evaluate these pathways in cumulus cells of infertile women with the disease, as well as their impact on the acquisition of oocyte competence., (Copyright © 2020 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Endometriosis (EMS) is a gynecologic disorder associated with infertility and characterized by the endometrial-type mucosa outside the uterine cavity. Currently available treatment modalities are limited to undesirable effects. Thus, in the present study, we sought to study the pathogenesis mechanism of EMS. For this purpose, the ectopic and eutopic endometrial tissues were resected from 86 patients with EMS and 54 infertile patients without EMS, respectively. The regulatory mechanism among HES family bHLH transcription factor 5 (HES5), transforming growth factor-beta (TGF-β)-induced factor 1 (TGIF1), F-box, and WD repeat domain containing 7 (FBXW7) was studied by performing co-immunoprecipitation, dual-luciferase reporter gene assay, and chromatin immunoprecipitation, respectively. A mouse model of EMS was established to verify the aforementioned regulatory mechanism in vivo. Upregulation of HES5 and TGIF1, as well as downregulation of FBXW7, was observed in EMS endometrial tissues and human endometrial stromal cells (hESCs), respectively. The overexpression of HES5 was found to suppress the FBXW7 transcription and TGIF1 degradation, resulting in the inactivation of the TGF-β signaling pathway, as well as inhibition of hESC proliferation and invasion, thereby enhancing apoptosis. Results from a mouse model of EMS showed that the presence of HES5 contributed to the alleviation of EMS. Collectively, we attempted to provide a mechanistic insight into the unrecognized roles of the HES5/FBXW7 in EMS progression., (© 2021 Federation of American Societies for Experimental Biology.)

Although N-arachidonoylethanolamine (AEA; also known as anandamide) is present in human follicular fluid (FF), its regulation remains unknown. Therefore, the aims of the present study were to: (1) investigate the relationships between FF AEA concentrations in women undergoing assisted reproductive technology and their age, body mass index, ART characteristics and fertility treatment outcomes; and (2) assess how different inflammatory patterns may trigger AEA production by human granulosa cells (hGCs). FF AEA concentrations were higher in women undergoing IVF than in those undergoing intracytoplasmic sperm injection group. FF AEA median concentrations were lower in women undergoing ART because of male factor infertility than in women with endometriosis (1.6 vs 2.5nM respectively), but not women with tubal, hormonal or unexplained infertility (1.6, 2.4 and 1.9nM respectively). To evaluate the effects of macrophages on AEA production by hGCs, hGCs were cocultured with monocyte-derived macrophages. The conditioned medium from M1 polarised macrophages increased AEA production by hGCs. This was accompanied by an increase in AEA-metabolising enzymes, particularly N-acyl phosphatidylethanolamine-specific phospholipase D. The results of the present study show that high FF AEA concentrations in patients with endometriosis may be associated with the recruitment of inflammatory chemokines within the ovary, which together may contribute to the decreased reproductive potential of women with endometriosis. Collectively, these findings add a new player to the hormone and cytokine networks that regulate fertility in women.

There is a statistically significant difference in the frequency of implantation in the group of patients with endometriosis associated with infertility compared with the control group. This has been confirmed by a number of different studies. The aim of the study to expand the understanding of the pathogenesis of implantation failures in patients with infertility associated with endometriosis Materials and research methods: The present study included 83 women aged 29 to 43 years (the average age was 33 ± 3.2 years) with a diagnosis of endometriosis (ICD10 code N80.9 Endometriosis, unspecified), as well as infertility (ICD10 code N 97.8, Female infertility of other origin) and repeated implantation failures. All patients of the studied cohort underwent an immunohistochemical study of endometrial biopsy samples taken by the pipel-biopsy of the endometrium during the period of the supposed "implantation window". Research results: Significant decrease in the immunological labeling of VEGF-A in samples from the ERIF group by ∼2.7 times in comparison with EF group ( p  < .05), the indices of expression of the proapoptotic protein CASP3 are increased in the samples of the ERIF group in comparison with the EF group (by ∼2.7 times, p  < .05) and significant decrease in the expression of HOXA10 in the stromal and glandular compartments (2.4 times; 57.2 vs. 23.5%, p  < .05). Conclusion: On the basis of the obtained results of the study, it should be concluded that the basis of implantation impairment in patients with repeated implantation failures associated with endometriosis lies in angiogenetic and apoptotic disorders and leads to implantation failure in the eutopic endometrium due to desynchronous transformation of the epithelial-mesenchymal compartment and disruption of endometrial trophism.

Objective: To evaluate the positive predictive value (PPV) of endometrial BCL-6 overexpression as a noninvasive screening test endometriosis in patients undergoing in vitro fertilization (IVF)., Methods: Retrospective cohort study at a university-affiliated private practice. Inclusion criteria were reproductive age females currently undergoing IVF with a diagnosis of unexplained infertility or unexplained recurrent pregnancy loss. Those with endometrial BCL-6 overexpression underwent laparoscopic surgery with an indication for treatment of suspected endometriosis. The primary outcome was the PPV of endometrial BCL-6 testing to surgically diagnose endometriosis. Statistical analysis was performed using SPSS v.25.0., Results: Seventy-five patients met inclusion criteria for our study. The PPV of BCL-6 testing for endometriosis was 96%. Of those patients without endometriosis, 100% had other inflammatory pelvic pathologies, which were diagnosed and treated at the time of laparoscopy., Conclusions: Endometrial BCL-6 overexpression has a high PPV for diagnosing endometriosis and can help identify a patient population that may require surgical treatment before embryo transfer., Competing Interests: Conflicts of Interest: The authors declare no conflict of interest., (© 2020 by JSLS, Journal of the Society of Laparoscopic & Robotic Surgeons.)

Research Question: Do endometrial stromal cells from primary infertile patients with severe ovarian endometriosis display differential secretory profiles of inflammation-associated cytokines during the implantation window that may cause infertility?, Design: Forty-eight cytokines were measured in conditioned medium of isolated endometrial stromal cells obtained from primary infertile patients without endometriosis (control group, n = 12) or with stage IV ovarian endometriosis (ovarian endometriosis group, n = 14) using multiplex assays. Key cytokines showing differential secretory profiles were validated using Western immunoblotting. Cellular phenotypic validation was carried out in vitro by comparing proliferation and migration capacity between control (n = 6) and ovarian endometriosis (n = 7) groups., Results: CCL3, CCL4, CCL5, CXCL10, FGF2, IFNG, IL1RN, IL5, TNFA, and VEGF could be detected only in the conditioned media of stromal cells obtained from the ovarian endometriosis group. Among other cytokines detected in the conditioned media of both groups, CCL2 (P = 0.0018), CSF3 (P = 0.0017), IL1B (P = 0.0066), IL4 (P = 0.036), IL6 (P = 0.0039) and IL13 (P = 0.036) were found to be higher, whereas the concentration of IL18 was lower (P = 0.023) in the ovarian endometriosis group. Concentrations of CCL2, IL1B, IL4 and IL13 in conditioned medium reflected significant diagnostic performance for predicting ovarian endometriosis. Cellular phenotypic validation in vitro revealed an enhanced proliferative phenotype (P = 0.046) with no change in cell migratory capacity of endometrial stromal cells from the ovarian endometriosis group., Conclusions: Endometrial stromal cells derived from severe ovarian endometriosis samples displayed a hyperinflammatory and hyperproliferative bias in the endometrial stroma during the 'window of implantation' putatively causing loss of fecundability., (Copyright © 2020 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Research Question: Does 3-months of gonadotrophin releasing hormone agonist (GnRHa) treatment before IVF improve clinical pregnancy rate in infertile patients with endometriosis?, Design: Single-blind, placebo-controlled clinical trial of 200 infertile women with endometriosis assigned to use GnRHa (study group) or placebo (control group) for 3 months before IVF. Clinical, embryological outcomes and stimulation parameters were analysed. Clinical pregnancy rate was the primary endpoint. In a subgroup of 40 patients, follicular fluid levels of oestradiol, testosterone and androstendione were measured. Gene expression profile of CYP19A1 was analysed in cumulus and mural granulosa cells., Results: Implantation or clinical pregnancy rate were not significantly different between the two groups. Clinical pregnancy rates were 25.3% and 33.7% in the study and control groups, respectively (P = 0.212). Cumulative live birth rate was not significantly different: 22.0% (95% CI 13.0 to 31.0) in the study group and 33.7% (95% CI 24.0 to 44.0) in the control group (P = 0.077). Ovarian stimulation was significantly longer and total dose of gonadotrophins significantly higher in the study group (both P < 0.001). Serum oestradiol levels on the day of HCG were significantly lower in the study group (P = 0.001). Cancellation rate was significantly higher in the study group (P = 0.042), whereas cleavage embryos were significantly more numerous in the control group (P = 0.023). No significant differences in the expression of CYP19A1 gene in mural or cumulus granulosa cells or steroid levels in follicular fluid between the two groups were observed, but testosterone was significantly lower in the study group (P < 0.001)., Conclusion: Three-months of GnRHa treatment before IVF does not improve clinical pregnancy rate in women with endometriosis., (Copyright © 2020 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Background: Adenomyosis is a gynaecological condition with limited evidence of negative impact to endometrial receptivity. It is commonly associated with endometriosis, which has been shown to alter endometrial expression patterns. Therefore, the candidate genes identified in endometriosis could serve as a source to study endometrial function in adenomyosis., Methods: Transcripts/proteins associated with endometrial receptivity in women with adenomyosis or endometriosis and healthy women were obtained from publications and their nomenclature was adopted according to the HUGO Gene Nomenclature Committee (HGNC). Retrieved genes were analysed for enriched pathways using Cytoscape/Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and Reactome tools to prioritise candidates for endometrial receptivity. These were used for validation on women with ( n = 9) and without ( n = 13) adenomyosis., Results: Functional enrichment analysis of 173, 42 and 151 genes associated with endometriosis, adenomyosis and healthy women, respectively, revealed signalling by interleukins and interleukin-4 and interleukin-13 signalling pathways, from which annotated LIF , JUNB , IL6 , FOS , IL10 and SOCS3 were prioritised. Selected genes showed downregulated expression levels in adenomyosis compared to the control group, but without statistical significance., Conclusion: This is the first integrative study providing putative candidate genes and pathways characterising endometrial receptivity in women with adenomyosis in comparison to healthy women and women with endometriosis.

Research Question: What is the expression pattern of microRNA (miRNA) in exosomes isolated from eutopic endometrial stromal cells (EuESC) of women with endometriosis-associated infertility?, Design: Small RNA sequencing was conducted in exosomes isolated from EuESC of women with endometriosis-associated infertility (n = 3) and normal endometrial stromal cells (NESC) of fertile women without endometriosis (n = 3). The differentially expressed miRNA in exosomes derived from EuESC and NESC were identified. The functions of the differentially expressed miRNA were analysed by gene ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis., Results: Small RNA sequencing showed that the percentages of exosomal miRNA in the total small RNA isolated from EuESC and NESC were not significantly different (P = 0.7804). A total of 49 differentially expressed miRNA (fold change >1.5 and P < 0.05) were identified, including 26 up-regulated and 23 down-regulated in EuESC exosomes as compared with NESC exosomes. Functional analysis revealed that 12 miRNA were predicted to target homeobox A10 (HOXA10) and/or the leukaemia inhibitory factor (LIF) 3' untranslated region (UTR). Both HOXA10 and LIF mRNA expression levels were significantly decreased in EuESC compared with NESC (P = 0.0222 and 0.0395, respectively). In addition, the predicated target genes of these differentially expressed exosomal miRNA were significantly (P < 0.05) enriched in 76 pathways, including the MAPK and Wnt signalling pathways., Conclusions: The differential expression patterns of exosomal miRNA were identified. Many exosomal miRNA may be involved in regulating the endometrial receptivity of women with endometriosis-associated infertility., (Copyright © 2020 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Purpose: To screen out specific protein with different concentration in follicular fluid from advanced endometriosis and determine its direct effect on mouse oocytes matured in vitro . Methods: FF samples were obtained from 25 patients (EMS group, n = 15; control group, n = 10) to screen the differential proteins by using iTRAQ Labeling and 2D LC-MS. Transferrin (TRF) in was found significantly decreased in EMS group, which was verified using ELISA in enlarged FF samples (EMS group, n = 31; control group, n = 27). The contents of ferric ion in FFs were detected by ELISA and TRF saturations were calculated in two groups. Germinal vesicle (GV) oocytes of mouse were maturated in vitro interfered with the FFs in five groups, whose concentrations of TRF were modulated, and maturation in vitro rates were compared among groups. Results: The reduced concentration of TRF with three analogs and increased concentration of ferric ion were found in the FF of the EMS group ( p < 0.05). The numerical values of TSAT was 54.8% in EMS group, indicating iron overload in the FF. The EMS-FF showed significantly decreased maturation in vitro rate ( p < 0.05) of mouse oocytes, which was improved with the supplementation of TRF, compared with the control-FF. The effect was blocked by the TRF antibody ( p < 0.05). Conclusions: Being aware of the relatively small sample size, our results possibly suggest that TRF insufficiency and iron overload in FF from advanced EMS contribute to oocytes dysmaturity, which may be a cause of EMS-related infertility., (Copyright © 2020 Li, Ni, Zhang, Cai, Kuang and Yu.)

Endometriosis is widely associated with infertility in women of childbearing age, for which there have been no effective treatments. Recent studies suggest that the dysregulation of RNAs contributes to the pathogenesis of endometriosis, so we conduct the case-control genetic analysis to characterize the expression and interaction of different subtypes of RNAs in infertile women with endometriosis. The ectopic and eutopic endometrium of patients undergoing infertility treatment were collected and subjected to high throughput sequencing, and bioinformatics analysis was conducted to construct the competing endogenous RNA (ceRNA) network. As a result, the RNA interactive network was constructed in endometriosis, and a set of mRNAs such as cyclin-dependent kinase 1 (CDK1) and proliferating cell nuclear antigen (PCNA) along with their corresponding miRNAs and lncRNAs were found to promote the growth and death of endometrial stromal cells, which was essential for the pathogenesis of endometriosis. These data suggest that RNA crosstalk is a crucial segment in the development of endometriosis, where CDK1 and PCNA may serve as emerging targets for the treatment of endometriosis-related infertility in women of childbearing age.

Study Question: Compared to healthy women, is the profile of transcripts altered in the eutopic endometrium of infertile women with endometriosis during the implantation window (IW)?, Summary Answer: The eutopic endometrium of infertile women with endometriosis seems to be transcriptionally similar to the endometrium of infertile and fertile controls (FC) during the IW., What Is Known Already: Endometriosis is a disease related to infertility; nevertheless, little is known regarding the ethiopathogenic mechanisms underlying this association. Some studies evaluating the eutopic endometrium of endometriosis patients suggest there is an endometrial factor involved in the disease-related infertility. However, no study to date has evaluated the endometrial transcriptome (mRNA and miRNA) by next generation sequencing (NGS), comparing patients with endometriosis as the exclusive infertility factor (END) to infertile controls (IC; male and/or tubal factor) and FC., Study Design, Size, Duration: From November 2011 to November 2015 we performed a case-control study, where 17 endometrial samples (six END, six IC, five FC) were collected during the IW., Participants/materials, Setting, Methods: All endometrial samples had the RNA extracted. Two libraries were prepared for each one (mRNA and miRNA), which were sequenced, respectively, at HISEQ 2500 (RNA-Seq) and MiSeq System (miRNA-Seq), Illumina. The normalization and differential expression were conducted in statistical R environment using DESeq2 package. qPCR was used for data validation, which were analyzed by Kruskal-Wallis test and Dunn posttest (P < 0.05)., Main Results and the Role of Chance: RNA-Seq revealed no differentially expressed genes (DEG) among END, IC and FC groups. miRNA-Seq revealed three differentially expressed miRNAs (has-27a-5p, has-miR-150-5p, has-miR-504-5p) in END group compared to FC group. However, none of the miRNAs identified in the sequencing was validated by qPCR., Limitations, Reasons for Caution: The main limitation of this study was the small sample size evaluated as a result of the restrictive eligibility criteria adopted, limiting the generalization of the results obtained here. On the other hand, strict eligibility criteria, which eliminated factors potentially related to impaired endometrial receptivity, were required to increase the study's internal validity., Wider Implications of the Findings: This study brings new perspectives on the mechanisms involved in endometriosis-related infertility. The present findings suggest the eutopic endometrium of infertile women with endometriosis, without considering the disease's stage, is transcriptionally similar to controls during the IW, possibly not affecting receptivity. Further studies are needed to evaluate endometrial alterations related to endometriosis' stages., Study Funding/competing Interest(s): This study received financial support from the Sao Paulo Research Foundation (FAPESP-Fundação de Amparo à Pesquisa do Estado de São Paulo; fellowship 2011/17614-6, MGB) and from the National Council for Scientific and Technological Development (CNPq-Conselho Nacional de Desenvolvimento Científico e Tecnológico; INCT-National Institutes of Hormones and Woman's Health, grant 471 943/2012-6, 309 397/2016-2, PAN; fellowship 140 137/2015-7, MGB). The authors have no conflicts of interest., Trial Registration Number: N/A., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Endometriosis is frequently related to infertility and little is known about the mechanisms underlying this association. Some studies point to an endometrial factor involved in this condition, which could compromise embryo implantation. Progesterone plays crucial role in endometrial receptivity by acting through progesterone receptor ( PGR ) isoforms PR-A and PR-B whose expression is epigenetically regulated by DNA methylation, in a specific promoter region for each isoform. Epigenetic changes in PGR-A and PGR-B may be related to progesterone resistance of endometriosis-related infertility. In order to better understand the mechanisms involved in endometrial receptivity, this case-control study aimed to compare the methylation pattern of PGR-A and PGR-B in eutopic endometrium from infertile women with and without endometriosis during the secretory phase. Endometrial biopsies from 19 patients (10 infertile women with endometriosis and 9 infertile controls) with regular cycles were performed during the secretory phase and were dated according to Noyes' criteria. The percentage of DNA methylation at PGR-A and PGR-B was carried out by high-resolution melting assay. The PGR-A gene showed 0% of DNA methylation (unmethylated) in both control and endometriosis groups. However, PGR-B gene showed a partially methylated pattern in majority of the patients (n = 7), with methylation percentage corresponding to 50%, while in the control group the percentage of methylation was 20% (hypomethylated; P = .04). The increased percentage of methylation at PGR-B may be related to reduced gene expression, which could compromise the endometrial receptivity in patients with endometriosis.

Research Question: Is there any metabolomic evidence of impairment of the cumulus-oocyte complex (COC) microenvironment in the follicular fluid of women with endometriosis?, Design: A prospective observational study from January to July 2018 at the Angers University Hospital, France. Seventy-nine women undergoing IVF with or without intracytoplasmic sperm injection (ICSI) were included: 39 for endometriosis-related infertility and 40 controls with other causes of infertility. A targeted quantitative metabolomic and lipidomic analysis was performed., Results: Patient characteristics (age, body mass index, smoking status, hormonal profile and ovarian reserve markers) were comparable between the endometriosis and the control groups. There was no significant difference in the cumulative FSH dose used for stimulation between the endometriosis and the control groups (2732 versus 2257 IU, respectively). There were no differences in the oocyte maturity rates (72.2% versus 77.7%), or in the fertilization rates in IVF and ICSI (49.4% versus 50.2% and 76.4% versus 68.8%, respectively) between the endometriosis and control groups. Among the 188 metabolites analysed, 150 were accurately measured. Univariate analysis did not reveal any significant modification of metabolite concentrations, and none of the multivariate models discriminated between the two groups of patients, even when the study was restricted to the most severe form of endometriosis., Conclusions: No specific metabolomic signature of endometriosis was found in the follicular fluid of women undergoing IVF. These results suggest that there is no microenvironmental impairment of the COC in cases of isolated endometriosis among women with infertility., (Copyright © 2019 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Background: Endometriosis patients undergoing in vitro fertilization-embryo transfer (IVF-ET) treatment suffer from lower success rates. The success of IVF-ET is related to the receptivity of the uterus and the quality of embryos, and it is well known a patient's endometriosis does not impair the receptivity. Whether endometrioma should be removed surgically before IVF remains controversial. Studies have shown that endometrioma removal decreases peritoneal inflammation, but little information is available regarding the alteration in the cytokines of follicular fluid. The objective of this study was to examine the impact of endometrioma cystectomy on the outcome of IVF and the levels of intrafollicular inflammatory cytokines and to investigate correlations between cytokine concentrations and IVF outcomes., Method: A total of 41 women with endometriosis-associated infertility undergoing IVF were recruited; 13 patients (surgery group, S group) had surgery to remove the endometrioma before enrollment, and 28 patients (non-surgery group, NS group) were untreated before IVF. The follicular fluid from a dominant follicle was collected during oocyte retrieval, and the concentrations of sixteen soluble cytokines known to be involved in ovarian function were measured., Results: Among the soluble molecules examined in this study, chemokines and growth factors and a few are inflammatory cytokines were found in the follicular fluid of patients with endometriosis. In addition, the expression levels of chemokines, growth factors, and most inflammatory cytokines did not differ between the S and NS groups, but interleukin (IL)-18 levels were significantly lower in the NS group. However, the levels of IL-18 in the FF did not correlate with IVF cycle parameters. The implantation and clinical pregnancy rates were similar between the two groups, but the anti-Müllerian hormone (AMH) level was lower in the S group than in the NS group., Conclusions: These findings suggest that endometrioma surgery may potentially reduce the ovarian reserve and has little impact on the success rate of IVF. Ovarian endometriomas are not associated with cytokine profiles in FF from infertile women, and they are not likely to affect the quality of the oocyte and embryo as a result of an inflammatory mechanism.