Cellular and molecular basis for endometriosis-associated infertility

Beyond the surface: Does stage I-II endometriosis impact fertility? Exploring the challenges of mild disease

Endometriosis is one of the most common gynecologic conditions that women face throughout their lives. Despite advances in technology, diagnosis and treatment of this relapsing and remitting condition is still challenging for many women. This review focuses on literature pertaining to minimal/mild (stage I/II) endometriosis and its impact on fertility. The effectiveness of medical interventions to improve infertility and obstetric outcomes in both natural and assisted reproductive technologies cycles remains debated. The recent ESHRE guidelines suggests that operative laparoscopy could be considered for rASRM stage I/II endometriosis as it improves ongoing pregnancy rates.

Diminished Ovarian Reserve in Endometriosis: Insights from In Vitro, In Vivo, and Human Studies-A Systematic Review

Endometriosis, a prevalent disorder in women of reproductive age, is often associated with undesired infertility. Ovarian reserve, an essential measure of ovarian function that is crucial for maintaining fecundity, is frequently diminished in women with endometriosis. Though the causative relationship between endometriosis and reduced ovarian reserve is not fully understood due to the lack of standardized and precise measurements of ovarian reserve, there is ongoing discussion regarding the impact of interventions for endometriosis on ovarian reserve. Therefore, in this review, we investigate articles that have related keywords and which were also published in recent years. Thereafter, we provide a comprehensive summary of evidence from in vitro, in vivo, and human studies, thereby shedding light on the decreased ovarian reserve in endometriosis. This research consolidates evidence from in vitro, in vivo, and human studies on the diminished ovarian reserve associated with endometriosis, as well as enhances our understanding of whether and how endometriosis, as well as its interventions, contribute to reductions in ovarian reserve. Furthermore, we explore potential strategies to modify existing therapy options that could help prevent diminished ovarian reserve in patients with endometriosis.

N-glycans from serum IgG and total serum glycoproteins specific for endometriosis

Endometriosis is a chronic inflammatory gynaecological disease characterized by the growth of endometrial tissue outside the uterine cavity. There are currently no definitive non-invasive diagnostic tools. Glycosylation is the most common posttranslational modification of proteins and altered glycosylation has been found in many diseases, including chronic inflammatory conditions and cancer. Sialylation and galactosylation on serum IgG have previously been found to be altered in endometriosis and serum sialylation changed after Zoladex (Goserelin Acetate) therapy. Using IgG and whole serum glycoproteins, we investigated N-glycosylation in two clinical cohorts of women with and without endometriosis. PNGase F-digested serum samples were fluorescently labelled and N-glycans were profiled by ultra-performance liquid chromatography. Clinical data was collected to link glycomic findings with metabolic and hormonal profiles. Total serum glycoprotein and IgG glycosylation differed in patients with endometriosis compared to control cases. The most significantly altered was glycan peak 3 from IgG, containing bisected biantennary glycans, which was decreased in the endometriosis cohorts (p = 0.0000005-0.018). In conclusion, this is the first pilot study to identify changes in N-glycans from whole serum glycoproteins associated with endometriosis. A larger validation study is now warranted and such studies should include the follow-up of surgically and pharmacologically treated patients.

Expectant, Medical, and Surgical Management of Ovarian Endometriomas

Management options for ovarian endometriomas include expectant management, medical treatment, surgical treatment, in vitro fertilization (IVF), or a combination of the above. The choice of management depends on many clinical parameters that should be taken into consideration, the first of which is the main presenting symptom. Most patients are today referred to medical therapy as a first option in the case of associated pain, and to IVF in the case of associated infertility. When both symptoms are present, usually surgery is the preferred approach. Recently, however, surgical excision of an ovarian endometrioma has been associated with a postoperative reduction in the ovarian reserve, and recent guidelines suggest that the clinician should caution the patient as to the possible damage to the ovarian reserve in the case of surgery. However, evidence has been published as to a possible detrimental effect of the ovarian endometrioma on the ovarian reserve even if expectant management is followed. In this review, the current evidence on the conservative management of ovarian endometriomas, with particular focus on the issue of the ovarian reserve, is evaluated, and the different surgical techniques for the treatment of ovarian endometriomas are discussed.

Association Between Reproductive Health Factors and Musculoskeletal Injuries in Female Canadian Armed Forces Members

Background: Musculoskeletal injuries (MSKi) play a role in member retention in the military. In general, female military members have higher rates of MSKi than males and female reproductive health characteristics may be contributing to these disparities. This study seeks to characterize reproductive health factors in female Canadian Armed Forces (CAF) members and their relationship with MSKi. Materials and Methods: An electronic survey (SurveyMonkey^®) was made available to present and former CAF members 18-65 years of age. Responses were collected between September 2020 and February 2021. Seven female reproductive characteristics were assessed: age of menarche, menstrual cycle regularity, birth control use, having given birth while serving, endometriosis, early menopause, and secondary oligomenorrhea/amenorrhea. Binary logistic regressions were used to analyze associations between reproductive characteristics with repetitive strain (RSI) and acute injuries. Results: A total of 2,001 participants consented to the survey with 855 respondents being female. Females reporting menstrual cycles as never regular, irregular for a few months, who never had a period, and whose periods stopped while serving presented a greater likelihood of reporting RSI compared to their peers who reported regular menstrual cycles (adjusted odds ratio [aOR]: 1.898, confidence interval [CI]: 1.138-3.166). Participants who have experienced endometriosis presented a higher likelihood of reporting acute injuries than those who did not (aOR: 2.426, CI: 1.030-5.709). Conclusion: This examination of females within the CAF suggests that irregular menstrual cycles or absent periods increase the likelihood of experiencing MSKi, namely those categorized as RSI injuries and reporting endometriosis were associated with greater rates of acute injuries.

Uterine administration of C-X-C motif chemokine ligand 12 increases the pregnancy rates in mice with induced endometriosis

OBJECTIVE

To study the effect of intrauterine injection of C-X-C motif chemokine ligand 12 (CXCL12), also known as a stem cell chemoattractant (stromal cell-derived factor 1), on fertility and endometrial receptivity in mice with endometriosis.

DESIGN

Laboratory study.

SETTING

Academic Medical Center.

ANIMAL(S)

Fifty-six mice underwent chemotherapy and bone marrow transplantation. Thirty-six of these mice underwent either surgery to induce endometriosis (n = 20) or sham surgery (n = 16).

INTERVENTION(S)

Injection of CXCL12 as a potential therapeutic agent to improve fertility in endometriosis.

MAIN OUTCOME MEASURE(S)

Pregnancy rate, bone marrow-derived cell (BMDC) recruitment and endometrial receptivity markers.

RESULT(S)

The mice with or without endometriosis received a single uterine injection of either CXCL12 or placebo. Uterine injection of CXCL12 increased the pregnancy rates in a mouse model of endometriosis. Mice were euthanized after delivery, and implantation markers homeobox A11, alpha-v beta-3 integrin, and progesterone receptor were analyzed by immunohistochemistry, whereas green fluorescent protein positive BMDC recruitment was quantified by immunohistochemistry and immunofluorescence. The sham surgery groups without endometriosis had the highest cumulative pregnancy rate (100%) regardless of CXCL12 treatment. The endometriosis group treated with placebo had the lowest pregnancy rate. An increased pregnancy rate was noted in the endometriosis group after treatment with CXCL12. There was also an increase in BMDC recruitment and endometrial expression of progesterone receptor and alpha-v beta-3 integrin in the endometriosis group that received CXCL12 compared with that in the endometriosis group that received placebo.

CONCLUSION(S)

Uterine injection of CXCL12 increased the pregnancy rates in a mouse model of endometriosis. These results suggest that CXCL12 has a potential role as a therapeutic agent in women with infertility related to endometriosis and potentially other endometrial receptivity defects.

The effect of endometriosis on fertility in an animal model

The present experimental model aimed to investigate the possible effect of endometriosis on ovarian function by altering follicular maturation and development. This single-blind, randomized study included twenty-four female Sprague Dawley mice, 2.5 months old, weighing 160-200 grams. The animals were randomly separated into four groups on the day of the surgery. Each group consisted of 6 mice. The first group (A) consisted of healthy female mice (control group). The second group (B) consisted of mice subjected to surgical insertion of ovarian endometrioma. The third group (C) consisted of mice subjected to surgically induced diffuse intraperitoneal endometriosis, and the fourth group (D) consisted of mice subjected to surgically induced extraperitoneal endometriosis. According to our experimental model, endometriosis may affect ovarian function by increasing the number of luteinized unruptured follicles (follicles that have undergone luteinization without prior rupture).

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

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

Evaluation of Women's Age and Ultrasonographic Features to Choose Surgical Treatment for Endometriosis Associated with Ovarian Cancer

Adequate surgical management of malignant endometriosis remains a clinical challenge in gynecology. Age, sonography variables, and tumor biomarkers have been reported as candidates in the clinical decision. This study aims were to analyze the factors of women’s age, body mass index, ultrasound features, and tumor biomarkers to predict endometriosis-associated ovarian cancer in a large series of endometriomas and to study the surgical treatment performed in this cohort. In this retrospective study, we reviewed the medical records of patients with ultrasound diagnosis of ovarian cyst classified as endometrioma (benign as well as with risk of malignancy), surgically treated in the endometriosis unit of Hospital Universitario La Paz (Madrid, Spain) between January 2019 and July 2021. According to the final histology examination, the women were clustered as non-endometriosis-associated ovarian cancer (OE, benign endometriomas, n = 59) and endometriosis-associated ovarian cancer (EAOC) (n = 17). Demographic, clinical, and surgical data were collected from these women. International Ovarian Tumor Analysis (IOTA) criteria were assessed for the ultrasound examination. The age of the women in the EAOC group was 50.0 [43.0; 63.0] years, which was significantly higher than OE (39.0 [34.0; 46.0] years; p-value < 0.001). In addition, the body mass index for the OE group (24.9 ± 5.3 kg/m2) was significantly higher than for the EAOC group (23.3 ± 4.6 kg/m2; p-value < 0.001). However, the tumor biomarker levels (CA 125, CA 19.9 and He4) were not significantly different among the groups. We performed 51.4% cystectomies and 48.6% adnexectomies, with an association between the adnexectomy and EAOC group (p-value < 0.001). In addition, a significant association was found between ultrasound features suspicious for malignancy and the EAOC group. Conclusively, women’s age and ultrasound features, such as papillary projections, septa, and positive echo-Doppler, were the main factors to consider when evaluating the malignancy risk associated with endometriosis.

CSF-1-induced DC-SIGN+ macrophages are present in the ovarian endometriosis

BACKGROUND

Researchers have found that macrophages are the predominant cells in the peritoneal fluid (PF) of endometriosis patients. CSF-1 has been found to accumulate in the lesions and PF of endometriosis patients, and CSF-1 induces THP-1-derived macrophages to polarize toward a CD169⁺ DC-SIGN⁺ phenotype. Does the cytokine CSF-1 induce monocytes to differentiate into macrophages with a DC-SIGN⁺ phenotype in endometriosis?

METHODS

The level of CSF-1 in the endometrium of control subjects, and the eutopic, and ectopic endometrium of endometriosis patients was evaluated by real-time polymerase chain reaction (qRT-PCR) and was determined by enzyme-linked immunosorbent assay (ELISA) in the PF of control and endometriosis patients. CSF-1 expression was examined with a MILLIPLEX MAP Mouse Cytokine/Chemokine Magnetic Bead Panel. DC-SIGN⁺ macrophages were detected by immunohistochemical staining of tissues and flow cytometric analysis of the PF of control subjects (N = 25) and endometriosis (N = 35) patients. The phenotypes and biological activities of CSF-1 -induced macrophages were compared in an in vitro coculture system with peripheral blood lymphocytes from control subjects.

RESULTS

In this study, we found that the proportion of DC-SIGN⁺ CD169⁺ macrophages was higher in the abdominal immune microenvironment of endometriosis patients. CSF-1 was primarily secreted from ectopic lesions and peritoneum in mice with endometriosis. In addition, CSF-1 induced the polarization of macrophages toward a DC-SIGN⁺ CD169⁺ phenotype; this effect was abolished by the addition of an anti-CSF-1R antibody. CSF-1 induced the generation of DC-SIGN⁺ macrophages, leading to a depressed status of peripheral blood lymphocytes, including a high percentage of Treg cells and a low percentage of CD8⁺ T cells. Similarly, blockade with the anti-CSF-1R antibody abrogated this biological effect.

CONCLUSIONS

This is the first study on the role of DC-SIGN⁺ macrophages in the immune microenvironment of endometriosis. Further study of the mechanism and biological activities of CSF-1-induced DC-SIGN⁺ macrophages will enhance our understanding of the physiology of endometriosis.

Maternal-Fetal Outcomes in Women with Endometriosis and Shared Pathogenic Mechanisms

The connection between endometriosis and pregnancy outcomes is trending among the research topics. Until recently, endometriosis and its painful symptomatology were considered to be alleviated by pregnancy. However, these beliefs have shifted, as emerging literature has demonstrated the role of this condition in affecting pregnancy evolution. The underlying pathogenesis of endometriosis is still poorly understood, all the more when pregnancy complications are involved. Debatable opinions on endometriosis associated with obstetric complications exist because of the potential bias resulting from the heterogeneity of preceding evidence. This review aims to evaluate the connection between endometriosis and adverse pregnancy outcomes and their shared pathogenic mechanisms. We searched PubMed and EMBASE and focused on the studies that include placenta praevia, premature rupture of membranes, spontaneous preterm birth, gestational hypertension, preeclampsia, obstetric hemorrhages (ante- and postpartum bleeding, abruptio placentae), miscarriage, stillbirth, neonatal death, gestational diabetes mellitus, gestational cholestasis, small for gestational age, and their association with endometriosis. Not only the risks of emergence were highlighted, but also the pathogenic connections. Epigenetic alterations of some genes were found to be mirrored both in endometriosis and obstetric complications. This review issues a warning for providing increased attention to pregnant women with endometriosis and newborns as higher risks of preeclampsia, placental issues, and preterm deliveries are associated.

Cytokines in culture media of preimplantation embryos during in vitro fertilization: Impact on embryo quality

Cytokine support of embryonic development includes promotion of implantation and protection of blastomeres from cell stress and apoptosis. Correlations between embryo quality and concentrations of specific cytokines in culture media of human embryos have been investigated for many years. The aim of this study was to assess the concentrations of cytokines in preimplantation embryo culture media and to investigate their relationships with embryo quality and in vitro fertilization (IVF) outcomes. Seventy-two samples were obtained from 39 infertile couples undergoing IVF or intracytoplasmic sperm injection treatment between October 2018 and May 2019. Each embryo was cultured separately, and the embryo culture medium was collected 72 h after fertilization. Before embryo transfer on day 3, a morphological evaluation of each embryo was performed. Cytokine concentrations of each culture medium were analyzed for 23 selected cytokines using the Multiplex Cytokine/Chemokine Panel II Assay (Merck Millipore®). The results were categorized into two groups (top-quality and non-top-quality embryos). The median age of the 39 patients was 34 years. Nine of 23 cytokines were quantified and compared between the top-quality embryo group and non-top-quality embryo group. Among the nine cytokines, CCL15, CCL27, and CXCL-12 were significantly elevated in the top-quality embryo group. These results suggested that specific cytokines measured in human embryo culture media can be used to predict embryo quality and IVF outcomes.

Identification and Validation of the Signatures of Infiltrating Immune Cells in the Eutopic Endometrium Endometria of Women With Endometriosis

Endometriosis is an oestrogen-dependent chronic inflammatory process with primary symptoms including dysmenorrhea, chronic pelvic pain, and infertility. The immune environment of the endometrium is essential for successful embryo implantation and ongoing pregnancy. In this study, we assessed the composition, density, and distribution of infiltrating immune cells in the endometria of women with endometriosis. Gene expression profiles of endometrial samples were downloaded from the Gene Expression Omnibus (GEO) database. We found that the TNF signalling pathway, the IL-17 signalling pathway, and the MAPK signalling pathway were significantly enriched in the eutopic endometria of women with endometriosis. The fractions and proportion of infiltrating immune cells were estimated by the CIBERSORT, MCP-counter, and ImmuCellAI methods. We found that the proportions of CD8⁺ T cells, activated NK cells, and follicular helper T cells were significantly higher in the endometria of women with endometriosis than in the endometria of normal controls, while the proportions of M2 macrophages and resting mast cells were significantly lower in the eutopic endometria. In GSE120103 (n = 36), we found that elevated CD8⁺ T cells in endometriosis increased the risk of infertility (P = 0.0019). The area under the receiver operating characteristic (ROC) curve (AUC) of CD8⁺ T cells to distinguish fertile and infertile endometriosis was 0.914. In clinical samples (n = 40), we found that the proportions of CD8⁺ T cells and CD56⁺ NK cells were significantly higher in the eutopic endometria of women with endometriosis than in the endometria of normal controls, while the proportion of CD163⁺ macrophages were lower in the eutopic endometria. The AUCs of CD8⁺ T cells and CD163⁺ macrophages were 0.727 and 0.833, respectively, which indicated that CD8 and CD163 were potential diagnostic markers for endometriosis. In conclusion, our results demonstrated that increased CD8⁺ T cells and CD56⁺ NK cells and decreased CD163⁺ macrophages within the eutopic endometria of women with endometriosis reveal a proinflammatory feature in the endometrial immune environment and that elevated CD8⁺ T cells increase the risk of infertility in women with the disease.

A History of Endometriosis Is Associated With Decreased Peripheral NK Cytotoxicity and Increased Infiltration of Uterine CD68+ Macrophages

Women with endometriosis may have a defective immune system. However, evidence of the immune responses of endometriosis patients with a history of endometriosis surgery is lacking, and the association between the location of endometriosis lesions and immune responses is unclear. This retrospective study included 117 females with reproductive failure and a history of endometriosis and 200 females with reproductive failure but without endometriosis to analyze their endometrial and peripheral immune responses. The results show that endometriosis was associated with decreased peripheral natural killer (NK) cytotoxicity and increased uterine macrophages. Peripheral NK cytotoxicity at effector-to-target ratios of 25:1 and 50:1 was significantly reduced in women with a history of endometriosis from that of the control group (26.6% versus 33.3% and 36.1% versus 43.3%, respectively, both P < 0.001). Furthermore, after further division of patients into three subgroups according to the location of endometriosis lesions, we observed that NK cytotoxicity in the endometriosis subgroups, especially the mixed endometriosis group, was strongly decreased from that of the controls (P = 0.001). The endometrial CD68⁺ macrophage proportion in the mixed endometriosis subgroup was higher than that in the control group (2.8% versus 2.1%, P = 0.043). In addition, the baseline estradiol (E2) level was weakly correlated with the percentage of endometrial macrophages (r = 0.251, P = 0.009), indicating a potential association among the endocrine system, endometrial immune environment, and endometriosis. This study indicated that peripheral NK cytotoxicity and endometrial immune cell profiles could be useful for diagnosing and treating endometriosis and endometriosis-related reproductive diseases.

Upregulation of fibroblast growth factor 2 contributes to endometriosis through SPRYs/DUSP6/ERK signaling pathway

Previous studies report that fibroblast growth factor 2 (FGF2) modulates Sproutys (SPRYs)/dual specificity phosphatase 6 (DUSP6)/extracellular signal-regulated kinase (ERK) signaling pathway in endometrial glandular epithelial cells. However, its role in endometriosis remains unclear. The expression patterns and localization of related proteins in endometrium patients' samples were determined using quantitative reverse transcription PCR, Western blotting, and immunohistochemistry, respectively. Human endometrial stromal cells (HESCs) were isolated and transfected with small interfering RNA (siRNA) targeting FGF2 (FGF2-siRNA). Cell viability was determined using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. It was found that FGF2 mRNA and protein levels were increased in the ectopic endometrium, whilst the mRNA and protein levels of SPRYs/DUSP6/ERK signaling pathway related-genes were dysregulated. Spearman's rank correlation analysis revealed a negative correlation between FGF2 and SPRYs/DUSP6 signaling pathway-related proteins. In vitro study demonstrated that FGF2 silencing suppressed cell proliferation. Our results suggest that FGF2 upregulation might contribute to endometriosis via the regulation of the SPRYs/DUSP6/ERK signaling pathway.

Endometriosis and polycystic ovary syndrome are diametric disorders

Evolutionary and comparative approaches can yield novel insights into human adaptation and disease. Endometriosis and polycystic ovary syndrome (PCOS) each affect up to 10% of women and significantly reduce the health, fertility, and quality of life of those affected. PCOS and endometriosis have yet to be considered as related to one another, although both conditions involve alterations to prenatal testosterone levels and atypical functioning of the hypothalamic-pituitary-gonadal (HPG) axis. Here, we propose and evaluate the novel hypothesis that endometriosis and PCOS represent extreme and diametric (opposite) outcomes of variation in HPG axis development and activity, with endometriosis mediated in notable part by low prenatal and postnatal testosterone, while PCOS is mediated by high prenatal testosterone. This diametric disorder hypothesis predicts that, for characteristics shaped by the HPG axis, including hormonal profiles, reproductive physiology, life-history traits, and body morphology, women with PCOS and women with endometriosis will manifest opposite phenotypes. To evaluate these predictions, we review and synthesize existing evidence from developmental biology, endocrinology, physiology, life history, and epidemiology. The hypothesis of diametric phenotypes between endometriosis and PCOS is strongly supported across these diverse fields of research. Furthermore, the contrasts between endometriosis and PCOS in humans parallel differences among nonhuman animals in effects of low versus high prenatal testosterone on female reproductive traits. These findings suggest that PCOS and endometriosis represent maladaptive extremes of both female life-history variation and expression of sexually dimorphic female reproductive traits. The diametric disorder hypothesis for endometriosis and PCOS provides novel, unifying, proximate, and evolutionary explanations for endometriosis risk, synthesizes diverse lines of research concerning the two most common female reproductive disorders, and generates future avenues of research for improving the quality of life and health of women.

Synthesis of [H-3]- and [C-14]-labeled elagolix

Gonadotropin-releasing hormone (GnRH) receptor antagonists are an important class of compounds designed to block the pituitary gland from synthesizing follicle-stimulating hormone and luteinizing hormone for the treatment of sex hormone dependent disorders. Elagolix (ABT-620) is currently approved for the treatment of pain associated with endometriosis and as a combination with estradiol and norethindrone acetate is approved for management of heavy menstrual bleeding due to uterine fibroids. In order to support the development of elagolix, we prepared [3 H]elagolix for preclinical metabolism studies and [14 C]elagolix for environmental risk assessment studies.

The Effects of Endometriosis on Ovarian Functions

Infertility is a main manifestation of endometriosis, though the exact pathogenesis of endometriosis-associated infertility remains unclear. Compromised ovarian functions may be one of the causes of endometriosis related infertility. The ovarian function can be classified into three basic elements, (1) production of ovarian hormones, (2) maintenance of follicular development until ovulation, and (3) reservoir of dormant oocytes (ovarian reserve). The effects of endometriosis on ovarian hormone production and follicular development are inconclusive. Ovarian endometrioma is common phonotype of endometriosis. Development of endometrioma per se may affect ovarian reserve. Surgery for endometriomas further diminish ovarian reserve, especially women with bilateral involvement. Early intervention with surgery and/or medical treatment may be beneficial, though firm evidence is lacking. When surgery is chosen in women at reproductive age, specific techniques that spare ovarian function should be considered.

Ovulation induction with clomiphene citrate or letrozole following laparoscopy in infertile women with minimal to mild endometriosis: a prospective randomised controlled trial

We conducted a prospective randomised controlled trial to explore the efficacy of clomiphene citrate (CC) and Letrozole (LTZ) for improving fecundity in infertile women with minimal to mild endometriosis after operative laparoscopy. We found that the ovulation rate of LTZ (88.7%) and CC (84.5%) were significantly higher than that of Control (70.5%) (p < .001). However, there was no significant difference in cumulative clinical pregnancy rates at 3, 6, 12 months after laparoscopy among the three groups (LTZ: 30%, 34.3%, 38.6% vs CC: 28.6%, 42.9%, 50.0% vs Control: 18.6%, 24.3%, 31.4%, respectively). No significant difference was observed in live-birth rate among the three groups (p = 1.125). For infertile women with minimal to mild endometriosis, ovulation induction with letrozole or clomiphene citrate after laparoscopy significantly increases ovulation rate, which are comparable between them; but does not demonstrate a significant advantage on improving pregnancy rate and live-birth rate when compared to laparoscopy alone.Impact statementWhat is already known on this subject? Endometriosis significantly decreases fecundity of women. Operative laparoscopy was recommended as an effective option to increase spontaneous pregnancy rate in infertile women with minimal to mild endometriosis. However, there is still no optimum treatment strategy for improving fertility of women with endometriosis.What do the results of this study add? For infertile women with minimal to mild endometriosis, ovulation induction with letrozole or clomiphene citrate after laparoscopy significantly increases ovulation rate, which are comparable between them; but does not demonstrate a significant advantage on improving pregnancy rate and live-birth rate when compared to laparoscopy alone.What are the implications of these findings for clinical practice and/or further research? Our results suggest that operative laparoscopy in conjunction with ovulation induction may improve fertility of women with minimal to mild endometriosis. Further research could focus on prolonging cycles of ovulation induction or choosing alternative ovarian stimulation protocols. More RCTs are still needed to compare the efficacy of letrozole with CC in ovulation induction.

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

BACKGROUND

Patients with endometriosis often experience infertility and have poor IVF outcomes, with low fertilization and pregnancy rates. Although many theories have tried to explain the mechanisms underlying infertility in these patients, none of them is conclusive.

OBJECTIVE AND RATIONALE

In this review, we discuss the pathologic mechanisms through which endometriosis likely leads to infertility along with the therapeutic options used to date to treat endometriosis-related infertility and, thereby, to improve IVF outcomes in patients with endometriosis.

SEARCH METHODS

We performed a comprehensive literature search of clinical outcomes in endometriosis and the molecular mechanisms contributing to oocyte quality using the PubMed database to identify human and animal studies published from 1992 until September 2020. In total, 123 manuscripts were included.

OUTCOMES

While some theories propose that endometriosis patients may have fertility problems as a result of decreased endometrial receptivity, others reinforce the idea that infertility could be associated with oocyte alterations and lower implantation rates. Single-cell RNA sequencing of oocytes from patients with endometriosis has identified dysregulated mechanisms involved in steroid metabolism and biosynthesis, response to oxidative stress and cell cycle regulation. Dysregulation of these mechanisms could result in the poor IVF outcomes observed in patients with endometriosis. Further, impaired steroidogenesis may directly affect oocyte and embryo quality. Increased oxidative stress in patients with endometriosis also has a detrimental effect on the follicular microenvironment, inducing cell cycle dysregulation in oocytes, poor oocyte quality, and infertility. Moreover, granulosa cells in the context of endometriosis undergo increased apoptosis and have an altered cell cycle that could adversely affect folliculogenesis, oocyte and embryo quality, and IVF outcomes. Endometriosis is also associated with inflammatory damage and impaired angiogenesis, which could be directly correlated with poor IVF outcomes. While therapeutic options using GnRH analogues, progestins and aromatase inhibitors do not improve endometriosis-related infertility, anti-inflammatory agents and antioxidant supplementation could improve oocyte quality as well as implantation and clinical pregnancy rates in patients with endometriosis.

WIDER IMPLICATIONS

Endometriosis is a heterogeneous disease whose pathogenesis is complex and could affect fertility by altering a collection of molecular mechanisms in oocytes. Thus, a single model is not sufficient to describe endometriosis-related infertility. Dysregulation of steroidogenesis, oxidative stress, cell cycle progression, inflammation and angiogenesis in the follicular environment and oocytes in individuals with endometriosis are all possible contributors to endometriosis-related infertility. Therefore, treatments targeting these mechanisms could be therapeutic alternatives to improve IVF outcomes for these patients.

The Potential Relationship Between Different Human Female Reproductive Disorders and Sperm Quality in Female Genital Tract

Spermatozoa should travel throughout the female reproductive tract to reach its ultimate goal, fertilization of the oocyte. At the ejaculation moment, millions of sperm within a few milliliters of the ejaculate are deposited at the cranial segment of vagina and make their journey to the fertilization site. This is done by means of various factors, such as sperm motility, the uterine and fallopian tubes contractility, and the ciliary movement of the lining cells. During this migration, spermatozoa interact with the female microenvironment both physically and molecularly. In this regard, the quality of the environmental conditions may affect this interaction. Therefore, some alterations in women's genital tract microenvironment, such as conditions that occur in female reproductive disorders, may have detrimental effects on sperm reproductive function. In this review, human sperm migration through the female tract is described, and the potential effects of different reproductive disorders at reproductive organs, such as vagina, uterine cervix, uterus, fallopian tubes, and ovary on sperm survival and quality, are also argued. The understanding of those conditions that may impair sperm fertility in the female genital tract can provide a more accurate diagnosis of the causes of infertility in couples. This can ultimately lead to the discovery of effective treatment approaches.

The evolutionary biology of endometriosis

We provide the first analysis and synthesis of the evolutionary and mechanistic bases for risk of endometriosis in humans, structured around Niko Tinbergen's four questions about phenotypes: phylogenetic history, development, mechanism and adaptive significance. Endometriosis, which is characterized by the proliferation of endometrial tissue outside of the uterus, has its phylogenetic roots in the evolution of three causally linked traits: (1) highly invasive placentation, (2) spontaneous rather than implantation-driven endometrial decidualization and (3) frequent extensive estrogen-driven endometrial proliferation and inflammation, followed by heavy menstrual bleeding. Endometriosis is potentiated by these traits and appears to be driven, proximately, by relatively low levels of prenatal and postnatal testosterone. Testosterone affects the developing hypothalamic-pituitary-ovarian (HPO) axis, and at low levels, it can result in an altered trajectory of reproductive and physiological phenotypes that in extreme cases can mediate the symptoms of endometriosis. Polycystic ovary syndrome, by contrast, is known from previous work to be caused primarily by high prenatal and postnatal testosterone, and it demonstrates a set of phenotypes opposite to those found in endometriosis. The hypothesis that endometriosis risk is driven by low prenatal testosterone, and involves extreme expression of some reproductive phenotypes, is supported by a suite of evidence from genetics, development, endocrinology, morphology and life history. The hypothesis also provides insights into why these two diametric, fitness-reducing disorders are maintained at such high frequencies in human populations. Finally, the hypotheses described and evaluated here lead to numerous testable predictions and have direct implications for the treatment and study of endometriosis. Lay summary: Endometriosis is caused by endometrial tissue outside of the uterus. We explain why and how humans are vulnerable to this disease, and new perspectives on understanding and treating it. Endometriosis shows evidence of being caused in part by relatively low testosterone during fetal development, that 'programs' female reproductive development. By contrast, polycystic ovary syndrome is associated with relatively high testosterone in prenatal development. These two disorders can thus be seen as 'opposite' to one another in their major causes and correlates. Important new insights regarding diagnosis, study and treatment of endometriosis follow from these considerations.

Altered transcriptome in cumulus cells of infertile women with advanced endometriosis with and without endometrioma

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.

Investigating the association of matrix metalloproteinase-2 gene variants with endometriosis in an Iranian population

OBJECTIVES

matrix metalloproteinases including matrix metalloproteinase-2 play a key role in endometrial extra cellular matrix breakdown in endometriosis. Aberrant expression of matrix metalloproteinase-2 has been reported in eutopic and ectopic endometrial tissue of endometriosis patients so altered expression of matrix metalloproteinase-2 due to polymorphisms may lead to establishment and progression of endometriosis. In this study the association between -735 C/T (rs2285053) and -1575 G/A (rs243866) variants of matrix metalloproteinase-2 gene with presence of endometriosis in an Iranian population were investigated for the first time.

STUDY DESIGN

A case-control association study was conducted to investigate the role of MMP-2-735 C/T and _1575 G/A variants in development of endometriosis. Polymerase chain reaction-restriction fragment length polymorphism method was used to determine genotype frequencies of these variants in 100 endometriosis patients and 200 normal samples. Total genomic DNA was extracted from blood samples and single-nucleotide polymorphism flanking regions were amplified using designed specific primers. Enzymatic digestion was performed using Pag I and Hinf I restriction enzymes for rs2285053 and rs243866 variants, respectively. Statistical analysis was ascertained using statistical package for social science version 16 and "SHEsis" software.

RESULTS

There were no significant differences in genotype frequencies of rs2285035 (-735C/T) variant between case and control groups (CC + CT vs. TT p = 0.40; OR = 0.50, 95 % CI 0.100-2.551). There were also no significant differences for C allele frequencies in both case and control groups (p = 0.9). For variant rs243866 (-1575 G/A) the differences in genotype frequencies between case and controls group were determined to be significant (GG + GA vs. AA p = 0.041; OR = 6.46, 95 % CI 0.82-50.43). The frequency of G allele was significantly different in case and control groups (p = 0.037).

CONCLUSION

In conclusion, existence of rs243866 variant in promoter region of matrix metalloproteinase-2 gene can increase the risk of endometriosis in Iranian women.

New treatment strategy for endometriosis using progestin-primed ovarian stimulation with dienogest: A prospective cohort study, comparison of dienogest versus dydrogesterone

Dienogest (DNG) is an oral progestin effective for the treatment of symptomatic endometriosis, such as reduction of endometrial lesion and control of pain intensity. Progestin-primed ovarian stimulation (PPOS) is a new controlled ovarian hyperstimulation (COH) regimen, and several reports have shown that dydrogesterone (DYG) is an appropriate progestin for PPOS. The purpose of this study was to evaluate the efficacy of DNG in patients undergoing PPOS during COH in comparison with DYG. This was a prospective, cohort, parallel-group, non-inferiority trial of 150 women with endometriosis undergoing assisted reproductive technology between February 2018 and May 2020 at the single fertility center. The assignment to each protocol was based on the optimal treatment for each patient. Patients taking DNG 2 mg continuously were assigned in the DNG group(n = 73). The other patients were allocated in DYG group(n = 77). All viable embryos were cryopreserved for subsequent transfer. The main outcome measures were the mature oocyte and fertilization rates. During this study, no premature LH surge was detected. A smaller number of oocytes were retrieved in the DNG group than in the DYG group (6.18 ± 3.60 vs. 9.85 ± 5.77); however, the rate of mature oocytes was significantly higher in the DNG group than in the DYG group (89.1 % vs. 78.9 %). The fertilization rate was comparable between two groups. Therefore, patients taking DNG for PPOS can continue endometriosis treatment and obtain good-quality embryos during COH. Further prospective randomized-controlled trial should be performed to confirm of this novel strategy of DNG.

Endometriosis screening in patients attending an IVF clinic: a proof-of-concept retrospective cohort study

Given that (i) endometriosis affects approximately 40% of women diagnosed with fertility problems and (ii) this condition may be an underestimated cause of idiopathic infertility, it is essential to identify high-risk patients for laparoscopic screening and reduce the diagnostic delay. We performed a retrospective analysis of 312 women (208 diagnosed with endometriosis and 104 controls) admitted to an in vitro fertilisation (IVF) unit in the city of Brest (France) between June 2007 and July 2014. As part of the women's infertility treatment, levels of cancer antigen 125 (CA-125) were assayed in blood samples collected on the day of oocyte retrieval. Surplus serum was used to set up a new sperm agglutination test. It was observed that sperm agglutination was significantly correlated with endometriosis and CA-125 levels (p < 0.01 for both). By building a decision tree, we identified a subpopulation of patients with low CA-125 levels and a high risk of endometriosis. This proof-of-concept study constitutes a first step towards a high-quality, controlled, multi-centre trial. If our preliminary results are confirmed, the decision tree should improve the medical care given to women in IVF programmes by identifying potential endometriosis sufferers for laparoscopic examination and enabling them to be counselled about precautionary measures.

The Anti-Inflammatory Effect of Octyl Gallate Through Inhibition of Nuclear Factor-κB (NF-κB) Pathway in Rat Endometriosis Model

BACKGROUND

Endometriosis is a chronic inflammatory condition associated with an increased risk of epithelial ovarian cancer. Our previous studies found that the anti-inflammatory effect of octyl gallate in endometriosis cell culture was more effective than gallic acid and heptyl gallate. This study aimed to analyze the anti-inflammatory effect of octyl gallate in rat endometriosis model.

METHODS

Thirty female Wistar rats were randomly divided into three groups. Group I was the sham-operated group, group II was the surgically-induced endometriosis group, whereas group III was the surgically-induced endometriosis group and each rat was administered with 20 mg of octyl gallate dissolved in 1 ml Na-CMC via oral gavage once a day for 30 days. When all rats were euthanized, the endometrial tissue from group I and last two groups were collected for further analysis. TNF-α levels were measured using Luminex, while non-phosphorylated NF-κB and COX-2 levels were analyzed using ELISA.

RESULTS

The average of non-phosphorylated NF-κB levels in group III (4.970±0.971 pg/mgP) was significantly higher than group II (3.97±0.656 pg/mgP). Moreover, the proportion of rats with the high level of non-phosphorylated NF-κB in group III was 45.6% higher than group II (p<0.05). The proportion of rats with the high level of COX-2 in group III was 22.3% lower than group II (p<0.05). However, there was no significant difference in TNF-α levels between all groups.

CONCLUSION

The anti-inflammatory effect of octyl gallate may has effects in NF-κB activation and reduction of COX-2 levels in rat endometriosis model.

Interleukin in endometriosis-associated infertility-pelvic pain: systematic review and meta-analysis

The objective is to study the significance of altered interleukin levels in endometriosis-related infertility or pelvic pain. The present systematic review and meta-analysis includes a discussion on the roles of interleukin in the physiopathology of endometriosis-associated infertility and/or pelvic pain. We included all studies in which interleukins in peritoneal fluid, follicular fluid or serum from patients were measured and that correlated the findings with either peritoneal or deep endometriosis-associated infertility or pelvic pain. For the meta-analysis, we selected studies on the following cytokines: interleukin-1 (IL-1), interleukin-6 (IL-6) and interleukin-8 (IL-8). Endometriosis is a chronic inflammatory disease. Inflammatory processes clearly participate in the etiology of endometriosis. Cytokines are mediators of inflammation, and increase in their concentration in plasma or other body fluids signals the presence and extent of tissue lesions. A number of studies have reported on the association between higher cytokine levels and progression or maintenance of endometriosis and coexisting infertility or pelvic pain. The results of the analyses support that an association exists between elevated serum IL-6 and/or IL-8 concentrations and the occurrence of endometriosis-associated infertility. Such association was not found for endometriosis-associated pain. In spite of accumulated evidence on the association of pro-inflammatory cytokines and endometriosis, it still is not clear if and how these mediators participate in the physiopathology of endometriosis-associated infertility or pelvic pain, in part due to poor quality of the evidence established in the vast majority of interleukins and challenges in endometriosis research reproducibility. In summary, the results of the analyses support that an association exists between elevated serum IL-6 and/or IL-8 concentrations and the occurrence of endometriosis-associated infertility.

Microarray analysis of cumulus cells in women with ovarian endometriosis undergoing intracytoplasmic sperm injection

Objective:

The aim of this study was to find the significantly altered genes in cumulus cells of women with ovarian endometriosis by using microarray and quantitative polymerase chain reaction analysis.

Methods:

Thirty women with ovarian endometriosis and 30 age–body mass index matched controls (women with infertility as a result of pure male factor) were enrolled in this study. Cumulus cells from study participants who underwent controlled ovarian hyperstimulation were isolated mechanically. Microarray comparative genomic hybridization was used to compare the transcriptome of cumulus cells from women with ovarian endometriosis and controls. According to the different expression levels in the microarrays and their putative functions, KRAS, ZNF322, and SDHA were selected and analyzed by real-time quantitative polymerase chain reaction.

Results:

There was no significant difference in the basal conditions between patients with endometriosis and controls, such as age, body mass index, basal follicle stimulating hormone and estradiol levels, and total gonadotrophin dosage. The gene expression profile of cumulus cells from patients with endometriosis was significantly different from that of controls. A total of 295 genes were significantly up- or down-regulated (p-value < 0.05 and absolute fold change > 1.5). For all of the genes adjusted p-value was found to be 0.999. Polymerase chain reaction analysis showed that KRAS and ZNF322 mRNA levels in the cumulus cells of patients with ovarian endometriosis were significantly up-regulated compared to controls (fold changes: 3.05 and 3.22, respectively).

Conclusion:

KRAS and ZNF322 mRNA levels in the cumulus cells of patients with ovarian endometriosis were significantly up-regulated.

Impacts of medroxyprogesterone acetate on oocytes and embryos: matched case-control study in women with stage III-IV ovarian endometriosis undergoing controlled ovarian hyperstimulation for in vitro fertilization

Background

This study investigated the effects of medroxyprogesterone acetate (MPA) on the oocytes and embryos in patients with advanced endometriosis who had a normal ovarian reserve and tubal infertility and received controlled ovarian hyperstimulation (COH) and explored the characteristics and pregnancy outcomes in subsequent frozen-thawed embryo transfer (FET) cycles.

Methods

In this prospective controlled study, 150 advanced endometriosis patients involving 150 in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI) cycles and 163 FET cycles and 150 age-matched tubal infertility patients requiring 150 IVF/ICSI cycles and 115 FET cycles were recruited. Patients with endometriosis were sub-grouped into surgery group (n=102) (they were diagnosed with ovarian endometriomas and underwent 102 IVF/ICSI and 115FET cycles) and aspiration group (n=48) [they had ovarian "chocolate" cysts (>3 cm) that were aspirated and underwent 48 IVF/ICSI and 74 FET cycles].

Results

Lower oocyte retrieval rate was noted in the endometriosis group than in the control group. Similar oocyte yield and peak estrogen (E₂) level were found in two groups. The rates of mature oocyte, fertilization, cleavage, high-quality embryo, viable embryo, cancellation, implantation, and clinical pregnancy were similar between two groups. A higher oocyte yield was observed in the EMS cyst group than in the surgery group.

Conclusions

The ovary response, oocytes, embryos and pregnancy outcome were not influenced by the advanced endometriosis and the use of MPA and also independent of endometrioma or cyst surgery.

Amine oxidase 3 is a novel pro-inflammatory marker of oxidative stress in peritoneal endometriosis lesions

Endometriosis is a common gynaecological disease of women in reproductive age, and is thought to arise from retrograde menstruation and implantation of endometrial tissue, mostly into the peritoneal cavity. The condition is characterized by a chronic, unresolved inflammatory process thereby contributing to pain as cardinal symptom in endometriosis. Elevated reactive oxygen species (ROS) and oxidative stress have been postulated as factors in endometriosis pathogenesis. We here set out for a systematic study to identify novel mechanisms and pathways relating to oxidative stress in ectopic peritoneal lesions. Using combined proteomic and transcriptomic approaches, we identified novel targets including upregulated pro-oxidative enzymes, such as amine oxidase 3/vascular adhesion protein 1 (AOC3/VAP1) as well as downregulated protective factors, in particular alkenal reductase PTGR1 and methionine sulfoxide reductase. Consistent with an altered ROS landscape, we observed hemoglobin / iron overload, ROS production and lipid peroxidation in ectopic lesions. ROS-derived 4-hydroxy-2-nonenal induced interleukin IL-8 release from monocytes. Notably, AOC3 inhibitors provoked analgesic effects in inflammatory pain models in vivo, suggesting potential translational applicability.

Estrogen-regulated CD200 inhibits macrophage phagocytosis in endometriosis

OBJECTIVES

Endometriosis (EMS) is a benign disease that is related to estrogen, immune disorders and inflammation. The purpose of this research was to determine the expression of CD200 in EMS and to clarify its role in the pathogenesis of the disease.

METHODS

The levels of serum CD200 in patients with and without EMS were determined by ELISA. Furthermore, the expression of CD200 in normal eutopic endometrium and ectopic endometrium was detected by immunohistochemistry and western blotting. The CD200 receptor (CD200R) in macrophages in peritoneal fluid (pMØ) obtained from controls and patients with EMS was examined by western blotting. CD200 expression in human endometrial stromal cells (HESCs) stimulated with 17β-estradiol (E₂) was measured by western blotting. Furthermore, macrophages were stimulated with different concentrations of CD200 and the effect on phagocytosis was analyzed.

RESULTS

The plasma CD200 levels of patients with EMS was significantly increased compared with controls (P = 0.0173, 95%CI [18.75, 159.6]). Compared with normal eutopic endometrium, the expression of CD200 was significantly increased in ectopic endometrial tissues. The CD200R expression in pMØ obtained from patients with EMS was increased compared with the controls (P = 0.0244). CD200 expression in HESCs stimulated with E₂ was up-regulated. As the levels of CD200 increased, macrophage phagocytosis in vitro gradually decreased.

CONCLUSIONS

CD200 is an estrogen-induced molecule that impairs macrophage phagocytosis and may contribute to the immune escape of ectopic lesions in EMS.

What Have We Learned from Animal Models of Endometriosis and How Can We Use the Knowledge Gained to Improve Treatment of Patients?

Endometriosis is a complex disorder with a high socio-economic impact. Development of effective novel drug therapies which can be given to women to relieve chronic pain symptoms without side effects such as hormone suppression is urgently required, but progress has been slow. Several different rodent models of 'endometriosis' have been developed, the majority of which mimic aspects of peritoneal disease (e.g. 'lesions' in peritoneal cavity either surgically or spontaneously attached to wall, mesentery, fat). Results obtained using these models have informed our understanding of aetiology including evidence for differential expression of regulatory factors in lesions and impacts on pain perception and fertility. Refinement of these models to ensure reproducibility, extension of models to replicate ovarian and deep disease, complementary in vitro approaches and robust experimental design are all needed to ensure preclinical drug testing results in positive findings in clinical trials and translation for patient benefit.

Identifying Mechanisms of Endometriosis-Associated Reduced Fecundity in a Rat Model: Novel Insights toward Understanding Human Infertility

The existence of endometriosis has been known since at least the nineteenth century, yet the lack of understanding of causes of infertility and therefore inadequate treatment approaches in endometriosis creates a significant challenge in reproductive medicine. Women worldwide suffer not only pain and infertility but also economical, societal, and physiological burdens. Studies of reproductive events in women are difficult to conduct due to a host of confounding personal and environmental factors and ethically limited due to the very nature of working with reproductive tissues and cells, especially embryos. Animal models are a viable adjunct to study mechanisms causing human reproductive anomalies and infertility in endometriosis. This chapter discusses reproductive anomalies causing infertility in endometriosis and well-established animal models which help decipher the problems and lead to heretofore unknown nonsurgical, nonhormonal methods to manage endometriosis in women. In addition, studies of effects of developmental exposure to endometriosis are revealing for the first time, in both female and male offspring, transgenerational subfertility in a rat model providing insights into the familial nature of endometriosis and possible epigenetic involvement.

Perineal scar endometriosis

Endometriosis is defined as the presence of ectopic endometrial tissue outside the uterine cavity. It is a benign condition commonly observed in women of the reproductive age group. It can occur in both pelvic and extra-pelvic sites. Moreover, pelvic endometriosis is relatively common, as compared to extra-pelvic endometriosis. The most frequent site for pelvic endometriosis is ovary. It can also affect rectum, uterosacral ligaments, rectovaginal septum, urinary bladder. Extra-pelvic endometriosis is rare and when it occurs, does so more frequently in surgical scar sites, especially in caesarean section scar. Endometriosis in an episiotomy scar is extremely rare but can lead to significant morbidity in patients due to local infiltration. This condition can be diagnosed by the presence of the classical clinical triad of history of episiotomy, tender nodule at the scar site and cyclical pain. Magnetic resonance imaging (MRI) is a very useful imaging modality to diagnose and assess the deeper extension of the lesion. Herein, we report one such case of episiotomy scar endometriosis in the perineum.

Pyrvinium pamoate inhibits proliferation and invasion of human endometriotic stromal cells

Endometriosis is characterized by the presence of functional endometrial tissue in other pelvic organs. This gynecologic problem occurs in 35–50% of women with pain and infertility. Endometriotic cells share some characteristics such as proliferation, migration, and invasion with tumor cells. Pyrvinium pamoate, an anthelmintic drug approved by the Food and Drug Administration, could inhibit the Wnt/β-catenin signaling pathway and its anticancer effects were examined by several researchers. In this study, 12 ectopic and eutopic endometrial biopsies from females with ovarian endometrioma and 12 endometrial biopsies from nonendometriotic females were obtained. Ectopic (EESCs), eutopic (EuESCs), and control (CESCs) endometrial stromal cells were isolated. Then, the effect of pyrvinium pamoate on the proliferation and invasiveness of in vitro cultured cells was evaluated. The proliferation of CESCs, EuESCs, and EESCs was significantly decreased after treatment with pyrvinium pamoate. In addition, treatment with pyrvinium pamoate significantly inhibited the invasiveness of CESCs, EuESCs, and EESCs compared to nontreated groups. The results of the present research showed that pyrvinium pamoate inhibits the proliferation and invasion of human endometriotic stromal cells in vitro, further investigations on the therapeutic potential of this compound in endometriosis are required.

The effects of endometrioma size and bilaterality on ovarian reserve

The aim of this study was to investigate the effects of endometrioma (OMAs) size and bilaterality on ovarian reserve. The patients with OMA were determined by ultrasonographic examination. Fifty patients with unilateral OMA (Group A), 30 patients with bilateral OMA (Group B), and 60 women without ovarian cysts (Group C) were included in this study. AMH levels were measured, and antral follicle count (AFC) was determined. The mean serum AMH levels were significantly lower in Group B than Groups C and A, and were significantly lower in Group A than Group C. There was a significant correlation between serum AMH level and OMA size in Group A (R = -.372, p = .008). OMAs per se appear to be associated with damage to the ovarian reserve. Increased OMA size is related to decreased AMH levels in patients with OMA. Bilateral OMAs have a more destructive effect on ovarian reserve.IMPACT STATEMENTWhat is already known on this subject? Previous Studies have demonstrated the effect of surgery on ovarian reserve but there have been contradictory findings reported about the effects of OMAs per se on serum AMH levels and it has not been clear what the relation between OMAs size and AMH levels is, if any.What the results of this study add? In this study, we found decreased AMH levels in patients with OMA. The results showed significant negative correlation between OMA size and AMH levels. The patients with bilateral OMAs had lower AMH levels than the unilateral ones.What the implications are of these findings for clinical practice and/or further research? Increasing OMA size might be harmful to ovarian reserve. Further studies should be done to evaluate whether increasing the size of the OMA is associated with a progressive decline in ovarian reserve and to better clarify the role of the OMAs per se or of laparoscopic surgery in the determination of damage to the ovarian reserve.

Dose-Dependent Decreased Fertility in Response to the Burden of Endometriosis in a Murine Model

Endometriosis is a gynecological disease caused by the growth of endometrial cells outside the uterus leading to inflammation, pelvic pain, and infertility. The relationship between the amount of ectopic uterine tissue growth and the severity of symptoms is still unclear. The presence or degree of pain and infertility does not correlate with the stage of disease as currently defined. Here, we report a clear dose-response relationship between the amount of ectopic tissue transplanted and the reproductive outcomes in a murine model of endometriosis. Endometriosis was induced in mice using various amounts of transplanted uterine tissue. Four groups of mice consisted of a sham surgery control or those transplanted with 1, 2, or 4 endometrial segments of 5 mm each. Pregnancy rates were significantly lower in those transplanted with 2 or 4 segments compared to sham or the 1 segment groups. We demonstrate that infertility does correlate with the extent of active disease. Current clinical staging systems do not account for disease activity and may inappropriately weight sequela of disease. Early recognition and treatment in women may help to minimize the effect of endometriosis on fertility. Here, we describe a mouse model of endometriosis and infertility that may be useful to elucidate the mechanisms of infertility in endometriosis.

Epigenetically regulated imprinted gene expression associated with IVF and infertility: possible influence of prenatal stress and depression

PURPOSE

Despite the growing body of research implying an impact of in vitro fertilization (IVF) on imprinted genes and epigenetics, few studies have examined the effects of underlying subfertility or prenatal stress on epigenetics, particularly in terms of their role in determining infant birthweights. Both subfertility and prenatal stressors have been found to impact epigenetics and may be confounding the effect of IVF on epigenetics and imprinted genes. Like IVF, both of these exposures-infertility and prenatal stressors-have been associated with lower infant birthweights. The placenta, and specifically epigenetically regulated placental imprinted genes, provides an ideal but understudied mechanism for evaluating the relationship between underlying genetics, environmental exposures, and birthweight.

METHODS AND RESULTS

In this review, we discuss the impacts of IVF and infertility on birthweight, epigenetic mechanisms and genomic imprinting, and the role of these mechanisms in the IVF population and discuss the role and importance of the placenta in infant development. We then highlight recent work on the relationships between infertility, IVF, and prenatal stressors in terms of placental imprinting.

CONCLUSIONS

In combination, the studies discussed, as well as two recent projects of our own on placental imprinted gene expression, suggest that lower birthweights in IVF infants are secondary to a combination of exposures including the infertility and prenatal stress that couples undergoing IVF are experiencing. The work highlighted herein emphasizes the need for appropriate control populations that take infertility into account and also for consideration of prenatal psychosocial stressors as confounders and causes of variation in IVF infant outcomes.

Effect of laparoscopic endometrioma cystectomy on anti-Müllerian hormone (AMH) levels

OBJECTIVE

To investigate temporary or long-term changes of AMH after laparoscopic endometrioma cystectomy and its dependency on characteristics of endometriomas.

METHODS

One hundred and seventy-one women, open-labeled prospective study; five groups divided according age ≤/> 35, uni-/bilateral, cyst ≤/> 7 cm, coagulation/suture surgery, stage III/IV; between- and within-group analyses after 1, 3, 6, and 12 months.

RESULTS

After 12 months, compared to pretreament, AMH decreased significantly for patients with bilateral cysts, cyst size >7 cm and endometriosis stage IV. In the between-group analysis all comparisons were significant, with exception of the surgery type. However, this was different performing the multiple linear regression analysis suggesting lower postoperative decrease using suturing technique. This analysis also showed higher age at pretreatment and bilateral cysts as risk factor for AMH decline.

CONCLUSIONS

Effects of endometrioma cystectomy on AMH are dependent on characteristics of the endometrioma, showing long-term a decrease in patients with larger, bilateral cysts and in stage IV endometriosis, but only short-time decrease in smaller, unilateral cysts and stage III which sometimes also can fully recover in AMH production within one year. In our study suture compared to coagulation surgery was protective, i.e. may lead to lower postoperative AMH decline.

Vibrational characterization of granulosa cells from patients affected by unilateral ovarian endometriosis: New insights from infrared and Raman microspectroscopy

Endometriosis is a chronic gynaecological disease characterised by the presence of endometrial cells in extra-uterine regions. One of the main factors impacting on the fertility of women affected by endometriosis is the poor oocyte quality. Granulosa Cells (GCs) regulate oocyte development and maintain the appropriate microenvironment for the acquisition of its competence; hence, the dysregulation of these functions in GCs can lead to severe cellular damages also in oocytes. In this study, luteinized GCs samples were separately collected from both ovaries of women affected by Unilateral Ovarian Endometriosis and analysed by infrared and Raman microspectroscopy. The spectral data were compared with those of GCs from women with diagnosis of tubal, idiopathic or male infertility (taken as control group). The coupling of these two spectroscopic techniques sheds new light on the alteration induced by this pathology on GCs metabolism and biochemical composition. In fact, the study revealed similar biochemical modifications in GCs from both ovaries of women affected by unilateral ovarian endometriosis, such as the alteration of the protein pattern, the induction of oxidative stress mechanisms, and the deregulation of lipid and carbohydrate metabolisms. These evidences suggest that unilateral endometriosis impairs the overall ovarian functions, causing alterations not only in the ovary with endometriotic lesions but also in the contralateral "healthy" one.

The underdeveloped innate immunity in embryonic stem cells: The molecular basis and biological perspectives from early embryogenesis

Embryonic stem cells (ESCs) have been intensively studied as a promising cell source for regenerative medicine. The rapid advancements in the field have not only proven the feasibility of ESC-based cell therapy, but also led to a better understanding of pluripotent stem cells (PSCs) as a unique cell population at an early stage of embryogenesis. Recent studies have revealed that both human and mouse ESCs have attenuated innate immune responses to infectious agents and inflammatory cytokines. These findings raise interesting questions about the rationale for ESCs, the PSCs experimentally derived from preimplantation stage embryos, to not have an innate defense mechanism that has been adapted so well in somatic cells. All somatic cells have innate immune systems that can be activated by pathogen-associated molecular patterns (PAMPs) or cellular damage-associated molecular patterns (DAMPs), leading to production of cytokines. The underdeveloped innate immunity represents a unique property of PSCs that may have important implications. This review discusses the immunological properties of PSCs, the molecular basis underlying their diminished innate immune responses, and the hypothesis that the attenuated innate immune responses could be an adaptive mechanism that allows PSCs to avoid cytotoxicity associated with inflammation and immune responses during early embryogenesis.

The effect of endometriosis on live birth rate and other reproductive outcomes in ART cycles: a cohort study

STUDY QUESTION

What is the effect of endometriosis compared to unexplained subfertility on live birth rate in women undergoing IVF and embryo transfer (ET)?

SUMMARY ANSWER

Endometriosis decreases live birth rate in women undergoing IVF-ET treatment, particularly with increasing severity of the disease.

WHAT IS KNOWN ALREADY

Endometriosis affects up to 50% of women seeking fertility treatment and is known to reduce fecundity. There remains a debate as to effects of endometriosis on the outcomes of IVF treatment, with live birth being a secondary outcome or not reported in most studies.

STUDY DESIGN SIZE DURATION

A retrospective cohort study analyzing data of IVF treatment cycles from January 2000 to December 2014 was carried out.

PARTICIPANTS/MATERIALS SETTING METHODS

Women with endometriosis (n = 531) and women with unexplained subfertility (n = 737) undergoing a first cycle of IVF-ET in a tertiary fertility treatment center were included in the study. The primary outcome was live birth. Other outcome measures were response to ovarian stimulation, embryo development and implantation rate. Bivariate and multivariate logistic regression analysis was performed and differences compared using Chi squared test of Student's t-test as appropriate.

MAIN RESULTS AND THE ROLE OF CHANCE

Women with endometriosis had 24% less likelihood of a live birth when compared to those with unexplained subfertility [odds ratio (OR) 0.76 (95% CI, 0.59-0.98) P = 0.035]. This effect became more apparent with increasing severity of endometriosis. Using multivariable logistic regression analysis, the trend for lower live birth rate remained but did not reach statistical significance [adjusted OR 0.76 (95% CI 0.56-1.03), P = 0.078]. Women with endometriosis were as likely as those with unexplained subfertility to have a singleton live birth when two embryos were transferred as opposed to a single ET [OR 1.38 (95% CI 0.73-2.62), P = 0.32 and OR 3.22 (95% CI 1.7-6.05), P = 0.0003, respectively]. Compared to women with unexplained subfertility, those with endometriosis had fewer oocytes retrieved [(10.54 (95% CI 10.13-0.95) and 9.15 (95% CI 8.69-9.6), respectively], lower blastocyst transfer [OR 0.24 (95% CI 0.12-0.5), P = 0.0001] and a significantly reduced implantation rate [OR 0.73 (0.58-0.92), P = 0.007].

LIMITATIONS REASONS FOR CAUTION

The study is limited by a retrospective design. By limiting the study to a single ET cycle, it was not possible to assess the cumulative outcome including use of all frozen embryos.

WIDER IMPLICATIONS OF THE FINDINGS

Endometriosis has similar phenotypes among women in different populations and would be expected to have a similar effect on fertility. These results are therefore generalizable to other populations of women.

STUDY FUNDING/COMPETING INTERESTS

None.

TRIAL REGISTRATION NUMBER

Not applicable.

Endometrial injury for patients with endometriosis and polycystic ovary syndrome undergoing medically assisted reproduction: current data and a protocol

We propose a study protocol capable of improving clinical outcomes following medically assisted reproduction (MAR) in infertile women with endometriosis and polycystic ovary syndrome (PCOS). The proposed research derives from the published evidence on the positive impact from endometrial injury (EI) and the beneficial nature of the intervention towards improved implantation rates. We primarily refer to the cluster of events and hypotheses, such as the mechanical cascade, the inflammatory response per se, the events accompanying wound healing, the immune cell recruitment and protein involvement, alterations in gene expression and the neo-angiogenesis theories, which have been previously investigated for this purpose. We are also exploring the possible problems in MAR cycles with negative outcomes in PCOS and endometriosis patients and we are proposing potential mechanisms on how this intervention might work. Our hypothesis states that the EI before the initiation of the MAR cycle can affect clinical pregnancy rates in patients with the aforementioned pathologies.

Endometriosis and in vitro fertilisation

The aim of the present review was to discuss a matter of concern in the clinical field of obstetrics/gynecology, namely the potency of in vitro fertilization (IVF) in the management of endometriosis-associated infertility. Endometriosis is a medical condition affecting one tenth of women in their fertile years, and accounts for up to 50% of infertile women. Thus, such high prevalence has established the necessity for investigating the effectiveness of available techniques in eradicating the disease and constraining infertility as well as the accompanying pain symptoms of endometriosis. The underlying mechanisms connecting endometriosis with low fecundity have been extensively studied, both in terms of genetic alterations and epigenetic events that contribute to the manifestation of an infertility phenotype in women with the disease. Several studies have dealt with the impact of IVF in pregnancy rates (PRs) on patients with endometriosis, particularly regarding women who wish to conceive. Results retrieved from studies and meta-analyses depict a diverse pattern of IVF success, underlining the involvement of individual parameters in the configuration of the final outcome. The ultimate decision on undergoing IVF treatment should be based on objective criteria and clinicians' experience, customized according to patients' individual needs.