Estrogen metabolism and action in endometriosis

Exploring the physiological role of the G protein-coupled estrogen receptor (GPER) and its associations with human diseases

Estrogen is a group of hormones that collaborate with the nervous system to impact the overall well-being of all genders. It influences many processes, including those occurring in the central nervous system, affecting learning and memory, and playing roles in neurodegenerative diseases and mental disorders. The hormone's action is mediated by specific receptors. Significant roles of classical estrogen receptors, ERα and ERβ, in various diseases were known since many years, but after identifying a structurally and locationally distinct receptor, the G protein-coupled estrogen receptor (GPER), its role in human physiology and pathophysiology was investigated. This review compiles GPER-related information, highlighting its impact on homeostasis and diseases, while putting special attention on functions and dysfunctions of this receptor in neurobiology and biobehavioral processes. Understanding the receptor modulation possibilities is essential for therapy, as disruptions in receptors can lead to diseases or disorders, irrespective of correct estrogen levels. We conclude that studies on the GPER receptor have the potential to develop therapies that regulate estrogen and positively impact human health.

Copper homeostasis and cuproptosis in gynecological disorders: Pathogenic insights and therapeutic implications

This review comprehensively explores the complex role of copper homeostasis in female reproductive system diseases. As an essential trace element, copper plays a crucial role in various biological functions. Its dysregulation is increasingly recognized as a pivotal factor in the pathogenesis of gynecological disorders. We investigate how copper impacts these diseases, focusing on aspects like oxidative stress, inflammatory responses, immune function, estrogen levels, and angiogenesis. The review highlights significant changes in copper levels in diseases such as cervical, ovarian, endometrial cancer, and endometriosis, underscoring their potential roles in disease mechanisms and therapeutic exploration. The recent discovery of 'cuproptosis,' a novel cell death mechanism induced by copper ions, offers a fresh molecular perspective in understanding these diseases. The review also examines genes associated with cuproptosis, particularly those related to drug resistance, suggesting new strategies to enhance traditional therapy effectiveness. Additionally, we critically evaluate current therapeutic approaches targeting copper homeostasis, including copper ionophores, chelators, and nanoparticles, emphasizing their emerging potential in gynecological disease treatment. This article aims to provide a comprehensive overview of copper's role in female reproductive health, setting the stage for future research to elucidate its mechanisms and develop targeted therapeutic strategies.

Research progress of dydrogesterone in the treatment of endometriosis

Endometriosis is a common gynecological disease among women of reproductive age. It is a chronic estrogen and progestin related inflammatory disease. At present, the main treatments for endometriosis are drug therapy and surgery. In drug therapy, progesterone is listed as the first-line recommendation in multinational guidelines. Dydrogesterone, as an oral reversal progesterone, can slow down the metabolism of progesterone, inhibit angiogenesis and extracellular matrix degradation to inhibit the proliferation of the ectopic endometrium, induce the atrophy of the ectopic endometrium through the pro-apoptotic pathway, and treat endometriosis through multiple mechanisms of regulating inflammatory factors to reduce inflammation. Clinically, dydrogesterone treatment of endometriosis can relieve patients' symptoms, promote fertility, be used in combination, and is safe. This article will review the mechanism and clinical application of dydrogesterone in the treatment of endometriosis.

A Preliminary Investigation of the Roles of Endometrial Cells in Endometriosis Development via In Vitro and In Vivo Analyses

Endometriosis is a complex gynecological disease that affects more than 10% of women in their reproductive years. While surgery can provide temporary relief from women's pain, symptoms often return in as many as 75% of cases within two years. Previous literature has contributed to theories about the development of endometriosis; however, the exact pathogenesis and etiology remain elusive. We conducted a preliminary investigation into the influence of primary endometrial cells (ECs) on the development and progression of endometriosis. In vitro studies, they were involved in inducing Lipopolysaccharide (LPS) in rat-isolated primary endometrial cells, which resulted in increased nuclear factor-kappa B (NF-κB) and vascular endothelial growth factor (VEGF) mRNA gene expression (quantitative polymerase chain reaction analysis, qPCR) and protein expression (western blot analysis). Additionally, in vivo studies utilized autogenic and allogeneic transplantations (rat to rat) to investigate endometriosis-like lesion cyst size, body weight, protein levels (immunohistochemistry), and mRNA gene expression. These studies demonstrated that estrogen upregulates the gene and protein regulation of cytoskeletal (CK)-18, transforming growth factor-β (TGF-β), VEGF, and tumor necrosis factor (TNF)-α, particularly in the peritoneum. These findings may influence cell proliferation, angiogenesis, fibrosis, and inflammation markers. Consequently, this could exacerbate the occurrence and progression of endometriosis.

Rab27b promotes endometriosis by enhancing invasiveness of ESCs and promoting angiogenesis

PROBLEM

Endometriosis (EMS) is an estrogen-dependent disease which is characterized with estrogen-dependent growth of ectopic endometrium and increased local estrogen production. EMS performs tumor-like biological functions such as invasiveness and angiogenesis. Rab27b is a member of the Rab family of GTPases, which is strongly associated with the growth, invasion and metastasis of a variety of tumors. However, little is known about the function of Rab27b in EMS. In this study, we intended to investigate the impact of Rab27b and its downstream molecule in the development of EMS.

METHOD OF STUDY

Normal endometrium and endometriotic lesions were collected to investigate the expression levels of Rab27b. Then, ESCs were transfected with Rab27b siRNA. We analyzed the influence of Rab27b on the proliferation and invasive activity of ESCs. Conditioned media harvested from Rab27b siRNA-treated ESCs were used to treat HUVECs. HUVEC Tube formation and ELISA were performed to explored the interactions between ESCs and HUVEC. In addition, ESCs were treated with different concentrations of estrogen. Based on biological database predictions, we explored possible mechanisms through which estrogen regulates the expression of Rab27b.

RESULTS

The expressions of Rab27b were significantly higher in endometriotic lesions than that in normal endometrium. Rab27b can promote the cell proliferation, migration and invasion of ESCs. The elevated expression of Rab27b, on the one hand, promotes the secretion of MMP9 and increases the invasiveness of ESCs. On the other hand, Rab27b may play a key role in the communication between ESC and endothelial cells, by simulating VEGF secretion and neovascularization. Besides, estrogen upregulated phosphorylated FOXO1 levels in ectopic ESCs, resulting in the promotion of Rab27b expression levels.

CONCLUSION

Rab27b plays a key role in the development of EMS, which may provide new insights into the pathogenesis of EMS. Our findings may also contribute to the development of therapeutic interventions for EMS.

Vanillin prevents the growth of endometriotic lesions through anti-inflammatory and antioxidant pathways in a mouse model

Endometriosis is an estrogen-dependent chronic inflammatory gynecological disease defined by the presence of endometrial glands and mesenchyme outside the uterine cavity, named ectopic endometrium. Recent studies showed that endometriosis is associated with hormone imbalance, inflammation and oxidative stress. As the main component of vanilla bean extract, vanillin is widely used as a flavoring agent in the food, pharmaceutical, and cosmetic industries. It is known for its anti-inflammatory, antibacterial, and antitumor properties, but its therapeutic efficacy in endometriosis has not been studied. In this study, we evaluated the roles of vanillin in this disease using an induced endometriotic mouse model. The results showed that vanillin significantly inhibited the growth of endometrial lesions. Compared with the control group, the weight and volume of lesions were reduced considerably in the vanillin-treated group, showing its fantastic ability to inhibit cell proliferation and promote apoptosis. In addition, in the treatment group, mRNA expression of the pro-inflammatory cytokines Tnfa, Infg, Il1b, and Il6 was reduced, the number of macrophages and neutrophils was decreased, and the NF-κB signaling pathway was inhibited, indicating that vanillin suppressed the inflammatory response in the ectopic endometrium. Besides, we found that the intensity of tissue reactive oxygen species (ROS) was significantly lower, and mitochondrial complex IV expression was reduced in the vanillin-treated group. Meanwhile, treatment of the immortalized human endometriotic epithelial cell line (11Z) with vanillin resulted in the downregulation of cyclin genes that drive the cell proliferation process, inhibited cell proliferation, promoted apoptosis, and downregulated the expression of LPS-induced inflammatory cytokines. Most importantly, our data showed that the vanillin treatment had only minimal effects on the eutopic endometrium with respect to the pregnancy process, indicating its safety to be used in treating endometriosis in adults. In conclusion, our data suggest that vanillin has potential therapeutic properties for endometriosis as a regulatory molecule of cell proliferation, apoptosis, inflammation, and oxidative stress.

Is There a Correlation between the Second-to-Four Digit Ratio (2D:4D) and Endometriosis? Results of a Case-Control Study

The second-to-four digit ratio (2D:4D) has been proposed as a marker of prenatal hormonal exposure. It is suggested that prenatal exposure to androgens results in a shorter 2D:4D ratio, whereas a prenatal oestrogenic environment results in a longer one. In addition, previous research has shown an association between exposure to endocrine-disrupting chemicals and 2D:4D in animals and humans. On the endometriosis side, hypothetically, a longer 2D:4D ratio, reflecting a lower androgenic intrauterine milieu, could represent an indicator of the presence of the disease. In this light, we have designed a case-control study to compare 2D:4D measurements between women with and without endometriosis. Exclusion criteria included the presence of PCOS and previous trauma on the hand that could impact the measurement of the digit ratio. The 2D:4D ratio of the right hand was measured using a digital calliper. A total of 424 participants (endometriosis n = 212; controls n = 212) were recruited. The group of cases included 114 women with endometriomas and 98 patients with deep infiltrating endometriosis. The 2D:4D ratio was significantly higher in women with endometriosis compared to controls (p = 0.002). There is an association between a higher 2D:4D ratio and the presence of endometriosis. Our results support the hypothesis claiming potential influences of intrauterine hormonal and endocrine disruptors exposure on the onset of the disease.

The Main Theories on the Pathogenesis of Endometriosis

Endometriosis is a complex disease, which is defined by abnormal growth of endometrial tissue outside the uterus. It affects about 10% of women of reproductive age all over the world. Endometriosis causes symptoms that notably worsen patient's well-being-such as severe pelvic pain, dysfunction of the organs of pelvic cavity, infertility and secondary mental issues. The diagnosis of endometriosis is quite often delayed because of nonspecific manifestations. Since the disease was defined, several different pathogenetic pathways have been considered, including retrograde menstruation, benign metastasis, immune dysregulation, coelomic metaplasia, hormonal disbalance, involvement of stem cells and alterations in epigenetic regulation, but the true pathogenesis of endometriosis remains poorly understood. The knowledge of the exact mechanism of the origin and progression of this disease is significant for the appropriate treatment. Therefore, this review reports the main pathogenetic theories of endometriosis based on current studies.

Emerging hallmarks of endometriosis metabolism: A promising target for the treatment of endometriosis

Endometriosis, characterized by ectopic endometrium growth in the extrauterine environment, is one of the most notable diseases of the female reproductive system. Worldwide, endometriosis affects nearly 10 % of women in their reproductive years and causes a significant decline in quality of life. Despite extensive investigations of endometriosis over the past years, the mechanisms of endometriosis pathogenesis remain unclear. In recent years, metabolic factors have increasingly been considered factors in endometriosis. There is compelling evidence regarding the progress of endometriosis in the context of severe metabolic dysfunction. Hence, the curative strategies and ongoing attempts to conquer endometriosis might start with metabolic pathways. This review focuses on metabolic mechanisms and summarizes current research progress. These findings provide valuable information for the non-intrusive diagnosis of the disease and may contribute to the understanding of the pathogenesis of endometriosis.

Targeting the formation of estrogens for treatment of hormone dependent diseases-current status

Local formation and action of estrogens have crucial roles in hormone dependent cancers and benign diseases like endometriosis. Drugs that are currently used for the treatment of these diseases act at the receptor and at the pre-receptor levels, targeting the local formation of estrogens. Since 1980s the local formation of estrogens has been targeted by inhibitors of aromatase that catalyses their formation from androgens. Steroidal and non-steroidal inhibitors have successfully been used to treat postmenopausal breast cancer and have also been evaluated in clinical studies in patients with endometrial, ovarian cancers and endometriosis. Over the past decade also inhibitors of sulfatase that catalyses the hydrolysis of inactive estrogen-sulfates entered clinical trials for treatment of breast, endometrial cancers and endometriosis, with clinical effects observed primarily in breast cancer. More recently, inhibitors of 17beta-hydroxysteroid dehydrogenase 1, an enzyme responsible for formation of the most potent estrogen, estradiol, have shown promising results in preclinical studies and have already entered clinical evaluation for endometriosis. This review aims to provide an overview of the current status of the use of hormonal drugs for the major hormone-dependent diseases. Further, it aims to explain the mechanisms behind the -sometimes- observed weak effects and low therapeutic efficacy of these drugs and the possibilities and the advantages of combined treatments targeting several enzymes in the local estrogen formation, or drugs acting with different therapeutic mechanisms.

Comparative G-Protein-Coupled Estrogen Receptor (GPER) Systems in Diabetic and Cancer Conditions: A Review

For many patients, diabetes Mellitus and Malignancy are frequently encountered comorbidities. Diabetes affects approximately 10.5% of the global population, while malignancy accounts for 29.4 million cases each year. These troubling statistics indicate that current treatment approaches for these diseases are insufficient. Alternative therapeutic strategies that consider unique signaling pathways in diabetic and malignancy patients could provide improved therapeutic outcomes. The G-protein-coupled estrogen receptor (GPER) is receiving attention for its role in disease pathogenesis and treatment outcomes. This review aims to critically examine GPER' s comparative role in diabetes mellitus and malignancy, identify research gaps that need to be filled, and highlight GPER's potential as a therapeutic target for diabetes and malignancy management. There is a scarcity of data on GPER expression patterns in diabetic models; however, for diabetes mellitus, altered expression of transport and signaling proteins has been linked to GPER signaling. In contrast, GPER expression in various malignancy types appears to be complex and debatable at the moment. Current data show inconclusive patterns of GPER expression in various malignancies, with some indicating upregulation and others demonstrating downregulation. Further research should be conducted to investigate GPER expression patterns and their relationship with signaling pathways in diabetes mellitus and various malignancies. We conclude that GPER has therapeutic potential for chronic diseases such as diabetes mellitus and malignancy.

Anogenital Distance and Endometriosis: Results of a Case-Control Study

AGD is the distance measured from the anus to the genital tubercle. Recent evidence suggests that a shorter AGD, a sensitive biomarker of the prenatal hormonal environment, could be associated with higher endometriosis risk. However, studies investigating AGD in affected women are scanty. We have set up a case-control study recruiting nulliparous women (aged 18-40 years) with endometriosis between 2017 and 2018. Cases were 90 women with a surgical or with a current nonsurgical diagnosis of endometriosis (n = 45 deep infiltrating endometriosis (DIE), and n = 45 ovarian endometrioma (OMA)). Controls were 45 asymptomatic women referring for periodical gynaecological care and without a previous diagnosis of endometriosis. They were matched to cases for age and BMI. For each woman, two measures were obtained using a digital calliper: AGD_AC, from the clitoral surface to the upper verge of the anus, and AGD_AF, from the posterior fourchette to the upper verge of the anus. Each distance was derived from the mean of six measurements acquired from two different gynaecologists. The mean ± SD AGD_AC in women with DIE, OMA and without a diagnosis of endometriosis was 76.0 ± 12.1, 76.1 ± 11.1 and 77.8 ± 11.4 mm, respectively (p = 0.55). The mean ± SD AGD_AF in women with DIE, OMA and without a diagnosis of endometriosis was 22.8 ± 5.0, 21.7 ± 9.0 and 23.7 ± 7.8 mm, respectively (p = 0.38). Our study failed to find an association between AGD and the presence of endometriosis. AGD does not seem to represent a reliable indicator of the presence of endometriosis to be used in clinical practice.

Elevated phosphorylation of estrogen receptor α at serine-118 in ovarian endometrioma

OBJECTIVE

To evaluate the phosphorylation of estrogen receptor α at serine-118 (phospho-ERα S118) in the endometrium, ovarian endometrioma, and deep infiltrating endometriosis (DIE).

DESIGN

Experimental study.

SETTING

University-affiliated hospital and academic research laboratory.

PATIENT(S)

Twenty-five patients underwent a hysterectomy, 18 patients underwent surgical removal of ovarian endometrioma, and 6 patients underwent DIE.

INTERVENTION(S)

Tissue samples were obtained from patients who underwent surgical procedures.

MAIN OUTCOME MEASURE(S)

Immunostaining for phospho-ERα S118, ERα, or phosphorylated p44/42 mitogen-activated protein kinase (phospho-p44/42 MAPK) was performed to evaluate the endometrium with or without endometriosis, ovarian endometrioma, and DIE. For in vitro analysis, endometrial epithelial cells (Ishikawa cells) were stimulated with estradiol (E2) or tumor necrosis factor alpha (TNFα), and the expression levels of phospho-ERα S118 and phospho-p44/42 MAPK were evaluated via Western blotting.

RESULT(S)

First, phospho-ERα S118 level was significantly higher in the glands and stroma of ovarian endometriosis samples than in those of endometrial and DIE samples. Second, colocalization of phospho-p44/42 MAPK and phospho-ERα S118 was observed in the glands of ovarian endometrioma. The proportions of cells strongly expressing phospho-p44/42 and phospho-ERα were 87% in phosphor-p44/42 MAPK-positive cells and 79% in phosphor-ERα-positive cells. Third, E2 stimulation significantly enhanced phospho-ERα S118 after 15 and 30 minutes in in vitro analysis using endometrial epithelial cells. Fourth, TNFα stimulation modestly but significantly enhanced phospho-ERα S118 after 15 and 30 minutes. Fifth, in Ishikawa cells, treatment with a p44/42 inhibitor (PD98059) significantly reduced phospho-ERα S118 by TNFα but not by E2.

CONCLUSION(S)

ERα-S118 phosphorylation was increased in ovarian endometriosis. Our findings may provide a new perspective for understanding the mechanism of increased ERα action in the pathophysiology of endometriosis.

Circulating estradiol and its biologically active metabolites in endometriosis and in relation to pain symptoms

OBJECTIVES

Endometriosis (EM) is an estrogen-dominant inflammatory disease linked to infertility that affects women of reproductive age. EM lesions respond to hormonal signals that regulate uterine tissue growth and trigger inflammation and pain. The objective of this study was to evaluate whether estradiol (E₂) and its biologically active metabolites are differentially associated with EM given their estrogenic and non-estrogenic actions including proliferative and inflammatory properties.

DESIGN

We performed a retrospective study of 209 EM cases and 115 women without EM.

METHODS

Pain-related outcomes were assessed using surveys with validated scales. Preoperative serum levels of estradiol (E₂) and estrone (E₁), their 2-, 4- and 16- hydroxylated (OH) and methylated (MeO) derivatives (n=16) were measured by mass spectrometry. We evaluated the associations between estrogen levels and EM anatomic sites, surgical stage, risk of EM, and symptoms reported by women. Spearman correlations established the relationships between circulating steroids.

RESULTS

Of the sixteen estrogens profiled, eleven were detected above quantification limits in most individuals. Steroids were positively correlated, except 2-hydroxy 3MeO-E₁ (2OH-3MeO-E₁). Higher 2OH-3MeO-E₁ was linked to an increased risk of EM (Odd ratio (OR)=1.91 (95%CI 1.09-3.34); P=0.025). Ovarian EM cases displayed enhanced 2-hydroxylation with higher 2MeO-E₁ and 2OH-E₁ levels (P< 0.009). Abdominal, pelvic and back pain symptoms were also linked to higher 2OH-3MeO-E₁ levels (OR=1.86; 95%CI 1.06-3.27; P=0.032).

CONCLUSIONS

The 2-hydroxylation pathway emerges as an unfavorable feature of EM, and is associated with ovarian EM and pain related outcomes.

Identification and Analysis of Potential Autophagy-Related Biomarkers in Endometriosis by WGCNA

Background: Endometriosis is a serious gynecological disorder characterized by debilitating pain, infertility and the establishment of innervated endometriosis lesions outside the uterus. Early detection and accurate diagnosis are pivotal in endometriosis. The work screened autophagy-related genes (ATGs) as potential biomarkers to reveal new molecular subgroups for the early diagnosis of endometriosis.

Materials and Methods: The gene lists of ATGs from five databases were integrated. Then, weighted gene co-expression network analysis (WGCNA) was used to map the genes to the gene profile of endometriosis samples in GSE51981 to obtain functional modules. GO and KEGG analyses were performed on the ATGs from the key modules. Differentially expressed ATGs were identified by the limma R package and further validated in the external datasets of GSE7305 and GSE135485. The DESeq2 R package was utilized to establish multifactorial network. Subsequently, one-way analysis of variance (ANOVA) was performed to identify new molecular subgroups. Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting were used to confirm the differential expression of hub ATGs, and the receiver operating characteristic (ROC) curve analysis and Spearman correlation analysis were applied to assess the diagnostic value of hub ATGs in 40 clinical samples and human primary endometrial stromal cells (ESCs).

Results: We screened 4 key modules and 12 hub ATGs and found the key genes to be strongly correlated with endometriosis. The pathways of ATGs were mainly enriched in autophagy, apoptosis, ubiquitin-protein ligase binding, and MAPK signaling pathway. The expression levels of EZH2 (Enhancer of Zeste homolog 2) and RND3 (also known as RhoE) had statistically significant changes with higher values in the endometriosis group compared with the controls, both in the tissue samples and primary ESCs. Besides, they also showed higher specificity and sensitivity by the receiver operating characteristic analysis and Spearman correlation analysis for the diagnosis of endometriosis. The TF-mRNA-miRNA-lncRNA multifactorial network was successfully constructed. Four new molecular subgroups were identified, and we preliminarily showed the ability of IQCG to independently differentiate subgroups.

Conclusion: EZH2 and RND3 could be candidate biomarkers for endometriosis, which would contribute to the early diagnosis and intervention in endometriosis.

Antiproliferative and antiangiogenic effects of ammonium tetrathiomolybdate in a model of endometriosis

AIMS

Copper (Cu) is involved in the endometriosis progression. Herein, an experimental endometriosis model was used to evaluate whether its chelation with ammonium tetrathiomolybdate (TM) affects the proliferation and angiogenesis in endometriotic-like lesions and the participation of oxidative stress in these processes.

MAIN METHODS

Female C57BL/6 mice were divided into three groups: sham-operated mice, endometriosis-induced mice, and TM-treated endometriosis-induced mice. Each animal in the third group received 0.3 mg of TM/day in their drinking water from the postoperative 15th day. The samples were collected after one month of induced pathology. In peritoneal fluids, Cu and estradiol levels were determined by electrothermal atomic absorption spectrometry and electrochemiluminescence, respectively. Endometriotic-like lesions were processed for the analysis of cell proliferation by PCNA immunohistochemistry, the expression of angiogenic markers by RT-qPCR, the presence of endothelial cells by immunofluorescent staining, and oxidative stress applying spectrophotometric methods.

KEY FINDINGS

TM treatment decreased Cu and estradiol levels, which were increased by this pathology. In lesions, TM induced: (a) a decrease in tissue weight and volume, (b) a decrease in PCNA-positive cells, (c) antiangiogenic effects by decreasing the number of blood vessels, the mRNA expression of fibroblast growth factor 2 (Fgf2) and platelet-derived growth factor subunit B (Pdgfb), and the presence of endothelial cells, (d) a decrease in antioxidant activity and an increase in lipid peroxidation.

SIGNIFICANCE

TM is a highly effective antiproliferative and antiangiogenic agent, modulating oxidative imbalance in endometriosis. Its anti-endometriotic potential is an attractive feature of TM as a possible non-hormonal treatment.

Brassica Bioactives Could Ameliorate the Chronic Inflammatory Condition of Endometriosis

Endometriosis is a chronic, inflammatory, hormone-dependent disease characterized by histological lesions produced by the presence of endometrial tissue outside the uterine cavity. Despite the fact that an estimated 176 million women are affected worldwide by this gynecological disorder, risk factors that cause endometriosis have not been properly defined and current treatments are not efficient. Although the interaction between diet and human health has been the focus of many studies, little information about the correlation of foods and their bioactive derivates with endometriosis is available. In this framework, Brassica crops have emerged as potential candidates for ameliorating the chronic inflammatory condition of endometriosis, due to their abundant content of health-promoting compounds such as glucosinolates and their hydrolysis products, isothiocyanates. Several inflammation-related signaling pathways have been included among the known targets of isothiocyanates, but those involving aquaporin water channels have an important role in endometriosis. Therefore, the aim of this review is to highlight the promising effects of the phytochemicals present in Brassica spp. as major candidates for inclusion in a dietary approach aiming to improve the inflammatory condition of women affected with endometriosis. This review points out the potential roles of glucosinolates and isothiocyanates from Brassicas as anti-inflammatory compounds, which might contribute to a reduction in endometriosis symptoms. In view of these promising results, further investigation of the effect of glucosinolates on chronic inflammatory diseases, either as diet coadjuvants or as therapeutic molecules, should be performed. In addition, we highlight the involvement of aquaporins in the maintenance of immune homeostasis. In brief, glucosinolates and the modulation of cellular water by aquaporins could shed light on new approaches to improve the quality of life for women with endometriosis.

Hypothetical roadmap towards endometriosis: prenatal endocrine-disrupting chemical pollutant exposure, anogenital distance, gut-genital microbiota and subclinical infections

BACKGROUND

Endometriosis is a gynaecological hormone-dependent disorder that is defined by histological lesions generated by the growth of endometrial-like tissue out of the uterus cavity, most commonly engrafted within the peritoneal cavity, although these lesions can also be located in distant organs. Endometriosis affects ~10% of women of reproductive age, frequently producing severe and, sometimes, incapacitating symptoms, including chronic pelvic pain, dysmenorrhea and dyspareunia, among others. Furthermore, endometriosis causes infertility in ~30% of affected women. Despite intense research on the mechanisms involved in the initial development and later progression of endometriosis, many questions remain unanswered and its aetiology remains unknown. Recent studies have demonstrated the critical role played by the relationship between the microbiome and mucosal immunology in preventing sexually transmitted diseases (HIV), infertility and several gynaecologic diseases.

OBJECTIVE AND RATIONALE

In this review, we sought to respond to the main research question related to the aetiology of endometriosis. We provide a model pointing out several risk factors that could explain the development of endometriosis. The hypothesis arises from bringing together current findings from large distinct areas, linking high prenatal exposure to environmental endocrine-disrupting chemicals with a short anogenital distance, female genital tract contamination with the faecal microbiota and the active role of genital subclinical microbial infections in the development and clinical progression of endometriosis.

SEARCH METHODS

We performed a search of the scientific literature published until 2019 in the PubMed database. The search strategy included the following keywords in various combinations: endometriosis, anogenital distance, chemical pollutants, endocrine-disrupting chemicals, prenatal exposure to endocrine-disrupting chemicals, the microbiome of the female reproductive tract, microbiota and genital tract, bacterial vaginosis, endometritis, oestrogens and microbiota and microbiota-immune system interactions.

OUTCOMES

On searching the corresponding bibliography, we found frequent associations between environmental endocrine-disrupting chemicals and endometriosis risk. Likewise, recent evidence and hypotheses have suggested the active role of genital subclinical microbial infections in the development and clinical progression of endometriosis. Hence, we can envisage a direct relationship between higher prenatal exposure to oestrogens or estrogenic endocrine-disrupting compounds (phthalates, bisphenols, organochlorine pesticides and others) and a shorter anogenital distance, which could favour frequent postnatal episodes of faecal microbiota contamination of the vulva and vagina, producing cervicovaginal microbiota dysbiosis. This relationship would disrupt local antimicrobial defences, subverting the homeostasis state and inducing a subclinical inflammatory response that could evolve into a sustained immune dysregulation, closing the vicious cycle responsible for the development of endometriosis.

WIDER IMPLICATIONS

Determining the aetiology of endometriosis is a challenging issue. Posing a new hypothesis on this subject provides the initial tool necessary to design future experimental, clinical and epidemiological research that could allow for a better understanding of the origin of this disease. Furthermore, advances in the understanding of its aetiology would allow the identification of new therapeutics and preventive actions.

Markers of Local and Systemic Estrogen Metabolism in Endometriosis

Estrogen metabolites (EMs) can work independently from their parent hormones. We hypothesize that in endometriosis, estrogen is metabolized preferentially along hormonally active pathways. We recruited 62 women with endometriosis (proven laparoscopically and histologically) and 52 control women (normal findings with laparoscopy) among patients undergoing surgery for pelvic pain and/or infertility during the proliferative phase of the menstrual cycle. Urinary samples were collected preoperatively. Biopsies from eutopic endometrium of control women and women with endometriosis were collected during surgery. EMs in urine and endometrial tissues were extracted and determined using Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS/MS). These included: 2-hydroxyestrone (2OHE1), 16-α hydroxyestrone (16α-OHE1), 2OHE1/16α-OHE1 ratio, 4-hydroxyestrone (4OHE1), 2-hydroxyestradiol (2OHE2), and 4-hydroxyestradiol (4OHE2). Eutopic endometrium of endometriosis patients, as compared to control endometrium, contained significantly higher level of 4OHE1 (0.03 (IQR: 0.03-0.265) versus 0.03 (IQR: 0.03-0.03) μg/g, respectively, P = 0.005), 2-OHE2 (0.241 (IQR: 0.1-0.960) versus 0.1 (IQR: 0.1-0.1) μg/g, respectively, P < 0.001), and 4-OHE2 (0.225 (IQR: 0.22-1.29) versus 0.0.2 (IQR: 0.2-0.2) μg/g, respectively, P < 0.001). Only 2OHE1 showed higher concentration in urine of women with endometriosis than controls (9.9 (IQR: 3.64-14.88) versus 4.5 (IQR: 1.37-17.00) μg/mg creatinine, respectively, P = 0.042). Eutopic endometrium of women with endometriosis metabolizes estrogen preferentially to the biologically active 2OHE2, and potentially genotoxic 4OHE1 and 4OHE2 metabolites. This contributes to further understanding of endometriosis etiology, its link to ovarian cancer, and could help identifying an endometrial biomarker of the disease.

Genetic variants in the nucleotide excision repair genes are associated with the risk of developing endometriosis

Endometriosis is a major health issue among women of reproductive age. However, its etiology has not yet been completely understood. We investigated 10 single nucleotide polymorphisms from six novel nucleotide excision repair genes and the susceptibility to endometriosis. A total of 153 patients with endometriosis were recruited during 2000-2010 from central Taiwan. Pathological confirmation was necessary for all patients, and exclusion criteria included the presence of leiomyoma, adenomyosis, or cancer of the uterine, cervix, or ovary and a prescription of hormone therapy. Furthermore, a total of 636 age-matched individuals without endometriosis were recruited during the same time period from central Taiwan. The polymerase chain reaction coupled with restriction fragment length polymorphism methodology was applied for genotyping. The multivariate logistic regression analysis showed that subjects carrying the ERCC1 rs11615 TT (OR = 2.04, 95% CI = 1.36-3.41), ERCC2 rs1799793 AA (OR = 1.86, 95% CI = 1.14-3.11), and ERCC6 rs2228528 AA genotypes (OR = 1.79, 95% CI = 1.13-2.83) exhibited significantly increased risks of developing endometriosis compared with their counterparts carrying the wild-type genotypes. This study suggests that certain single nucleotide polymorphisms of nucleotide excision repair genes excision repair cross-complementation group 1 (ERCC1, ERCC2, and ERCC6) predispose women to the development of endometriosis.

Pain-related behavior and brain activation in cynomolgus macaques with naturally occurring endometriosis

STUDY QUESTION

Can pain be objectively assessed in macaques with naturally occurring endometriosis?

SUMMARY ANSWER

Behavioral, pharmacological and in vivo brain imaging findings indicate that pain can be quantified in macaques with endometriosis.

WHAT IS KNOWN ALREADY

Endometriosis is characterized by abdominopelvic hypersensitity. The mechanism by which endometriosis evokes pain is largely unknown, as currently available analgesics offer limited pain relief. Thus, there is a need for both greater understanding of the in vivo mechanism of endometriosis-associated pain and better methods of testing novel therapeutics.

STUDY DESIGN, SIZE, DURATION

Pain-related behavior and brain activation were assessed in five cynomolgus macaques with endometriosis. Three healthy female macaques served as controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Abdominopelvic sensitivity to force was assessed with an algometer. Activation of brain areas using block design force stimulation and the effects of a single dose of the analgesic drug morphine and 2-month treatment with the progestin dienogest on brain activation were observed via functional magnetic resonance imaging.

MAIN RESULTS AND THE ROLE OF CHANCE

Pain response thresholds in macaques with endometriosis were significantly less than that of healthy macaques (P = 0.0003). In addition, non-noxious force activated the insula and thalamus, which was reduced with morphine and 2-month dienogest treatment.

LIMITATIONS, REASONS FOR CAUTION

The specific role of cysts, such as peritoneal cysts, in endometriosis pain was not explored. While non-noxious stimulation activated the insula and thalamus, macaques were sedated during fMRI scans. Current findings need further confirmation in a larger cohort.

WIDER IMPLICATIONS OF THE FINDINGS

The current study demonstrated central sensitization and related pain behavior in macaques with naturally occurring endometriosis. Altered functioning of the central nervous system could be the focus of future mechanistic studies and for the development of novel therapeutics.

STUDY FUNDING/COMPETING INTEREST(S)

Supported by a grant from the Shizuoka Industrial Foundation. All authors are employees of Hamamatsu Pharma Research, Inc.

Involvement of endoplasmic reticulum stress in regulation of endometrial stromal cell invasiveness: possible role in pathogenesis of endometriosis

Endoplasmic reticulum (ER) stress is known to reduce invasiveness in some cancer cells by inhibiting the AKT/mTOR pathway. A previous study from our laboratory suggested that ER stress is promoted by progesterone in human endometrial cells, which suggests that progesterone may inhibit endometrial cell invasiveness by up-regulating ER stress. Therefore, aberrant ER stress in response to progesterone may contribute to the altered invasiveness found in endometriotic tissues. To test this hypothesis, we elucidate whether ER stress is involved in regulation of human endometrial cell invasiveness through the AKT/mTOR pathway and if this involvement is associated with altered invasiveness in endometriotic cells. Specifically, we sought to determine the effects of ER stress on AKT/mTOR pathway by evaluating ER stress-mediated CHOP/TRIB3 signaling, a negative regulator of AKT. We found that ER stress marker GRP78 expression increased with CHOP and TRIB3 expression in normal endometrial stromal cells (NESCs) treated with tunicamycin, and this increase was accompanied by decreased AKT and mTOR activity and cellular invasiveness. Similarly, progesterone increased GRP78, CHOP and TRIB3 expression in NESCs. Subsequently, inhibition of AKT and mTOR activity decreased cellular invasiveness. This progesterone-induced decrease in cellular invasiveness was reversed by inhibition of ER stress. In contrast, progesterone did not change CHOP, TRIB3, AKT, mTOR or invasiveness in endometriotic cyst stromal cells. In contrast to normal endometrium, endometriotic tissues showed no changes in CHOP, TRIB3 and invasion-related proteins (MMP2 and MMP9) expression throughout the menstrual cycle. Taken together, our findings indicate that abnormal ER stress response to progesterone increased endometriotic stromal cell invasiveness via the AKT/mTOR pathway.

Progesterone's role in deep infiltrating endometriosis: Progesterone receptor and estrogen metabolism enzymes expression and physiological changes in primary endometrial stromal cell culture

To study progesterone signaling activation, we measured changes in extracellular pH as a reflection of Na+/H+ exchange (NHE) using a cytosensor microphysiometer and assessed progesterone receptor (PR) and estrogen metabolism enzymes mRNA expression in cultured endometrial cells from women with deep infiltrating endometriosis and healthy controls using real-time quantitative PCR. This study was conducted at a University hospital and included patients with and without deep infiltrating endometriosis (DIE). Primary endometrial stromal cells (ECs) from women with DIE and controls were treated with 17β-estradiol and progesterone prior to microphysiometer measurements and qPCR evaluations. Decreased progesterone responsiveness and decreased total nuclear PR and HSD17B1 mRNA expression were observed in cultured ECs from women with deep infiltrating endometriosis relative to those from control samples before and after hormone treatment. These cells also showed increased 17β-hydroxysteroid dehydrogenases types 2 (HSD17B2) relative to control group and increased expression of aromatase (CYP19) after exposure to progesterone. These physiological and expression patterns observed in ECs cultures from women with DIE reinforces previous findings in the literature supporting the progesterone resistance hypothesis in the pathogenesis of endometriosis.

Endometriosis-Associated Macrophages: Origin, Phenotype, and Function

Endometriosis is a complex, heterogeneous, chronic inflammatory condition impacting ~176 million women worldwide. It is associated with chronic pelvic pain, infertility, and fatigue, and has a substantial impact on health-related quality of life. Endometriosis is defined by the growth of endometrial-like tissue outside the uterus, typically on the lining of the pelvic cavity and ovaries (known as "lesions"). Macrophages are complex cells at the center of this enigmatic condition; they are critical for the growth, development, vascularization, and innervation of lesions as well as generation of pain symptoms. In health, tissue-resident macrophages are seeded during early embryonic life are vital for development and homeostasis of tissues. In the adult, under inflammatory challenge, monocytes are recruited from the blood and differentiate into macrophages in tissues where they fulfill functions, such as fighting infection and repairing wounds. The interplay between tissue-resident and recruited macrophages is now at the forefront of macrophage research due to their differential roles in inflammatory disorders. In some cancers, tumor-associated macrophages (TAMs) are comprised of tissue-resident macrophages and recruited inflammatory monocytes that differentiate into macrophages within the tumor. These macrophages of different origins play differential roles in disease progression. Herein, we review the complexities of macrophage dynamics in health and disease and explore the paradigm that under disease-modified conditions, macrophages that normally maintain homeostasis become modified such that they promote disease. We also interrogate the evidence to support the existence of multiple phenotypic populations and origins of macrophages in endometriosis and how this could be exploited for therapy.

PDCD4 suppresses proliferation, migration, and invasion of endometrial cells by inhibiting autophagy and NF-κB/MMP2/MMP9 signal pathway

Endometriosis (EM) is a kind of estrogen-dependent disease in reproductive-age women. Ovarian EM is the most common type. Although EM is a benign disease, it shares many similar features with cancers. Programmed cell death 4 (PDCD4), a newly identified tumor suppressor, plays an important role in inhibiting tumorigenesis and tumor progression at the transcriptional and translational levels. To explore the roles of PDCD4 in EM, we detected the expression of PDCD4 in control endometrium and eutopic/ectopic endometrium of ovarian EM patients, and analyzed the effects of PDCD4 on the biological behaviors of endometrial cell lines and primary endometrial cells. The results demonstrated that PDCD4 was downregulated in eutopic and ectopic endometrium of EM patients compared with control endometrium. PDCD4 effectively inhibited the proliferation and colony-forming ability of endometrial cells maybe by inhibiting cell autophagy. In addition, PDCD4 also suppressed the migration and invasion ability of endometrial cells, the mechanism may be related to NF-κB/MMP2/MMP9 signal pathway. Taken together, these results suggest that PDCD4 could be involved in the pathogenesis of EM, and provide a novel approach to target the aberrant PDCD4 expression in EM.

Aldo-keto reductase 1C3-Assessment as a new target for the treatment of endometriosis

Endometriosis is a common gynecological disorder, which is treated surgically and/ or pharmacologically with an unmet clinical need for new therapeutics. A completed phase I trial and a recent phase II trial that investigated the steroidal aldo-keto reductase 1C3 (AKR1C3) inhibitor BAY1128688 in endometriosis patients prompted this critical assessment on the role of AKR1C3 in endometriosis. This review includes an introduction to endometriosis with emphasis on the roles of prostaglandins and progesterone in its pathophysiology. This is followed by an overview of the major enzymatic activities and physiological functions of AKR1C3 and of the data published to date on the expression of AKR1C3 in endometriosis at the mRNA and protein levels. The review concludes with the rationale for using AKR1C3 inhibitors, a discussion of the effects of AKR1C3 inhibition on the pathophysiology of endometriosis and a brief overview of other drugs under clinical investigation for this indication.

Reduced inflammatory state promotes reinnervation of endometriotic-like lesions in TNFRp55 deficient mice

Endometriosis is a chronic gynecological disease, characterized by growth of endometrial tissue in ectopic sites due to alteration of peritoneal homeostasis and deregulation of apoptosis. Here we have examined whether TNFRp55 deficiency modulates the pro-inflammatory state and the reinnervation of endometriotic-like lesions in mice. Two-month-old female C57BL/6 mice, eight wild type (WT) and eight TNFRp55-/- (KO) were used in the study. Endometriotic-like lesions were induced experimentally. The right uterine horn was removed from the animal, divided longitudinally, cut in three square pieces and sutured to the intestine mesentery. After 4 weeks, the lesions and the peritoneal fluid were collected. The level of TNFα in the peritoneal fluid was evaluated by enzyme-linked immunosorbent assay (EIA). The expressions of COX2, GRα and GRβ were evaluated in the lesions by western blot and immunohistochemistry. β-III TUBULIN, BDNF and NGF protein concentrations were evaluated in the lesions by western blot. Gene expression of Pgp 9.5, SP and Th was analyzed by RT-PCR, whereas relative concentrations of TRKA, NTRp75, phosphorylated NFκB (pNFκB) and total NFκB in lesions were measured by EIA. Compared with the WT group, the KO mice showed lower TNFα levels in the peritoneal fluid and lower numbers of COX2 immunoreactive cells along with increased expression of GRα, β-III TUBULIN, Pgp 9.5, SP, Th, BDNF, NGF, NTRp75 and pNFκB in the lesions. Future histological studies will be necessary to confirm the sensory/sympathetic imbalance in the endometriotic-like lesions of the KO mice. Our results suggest that a reduced inflammatory state promotes reinnervation of endometriotic-like lesions in TNFRp55-/- mice. Chronic deregulation of TNF receptors can have serious consequences for women with advanced endometriosis.

Lesion development is modulated by the natural estrous cycle and mouse strain in a minimally invasive model of endometriosis

Many rodent models of endometriosis are invasive, involving surgery to implant donor endometrial tissue into recipient animals. Moreover, few studies have compared and contrasted lesions between rodent strains and estrous stages without exogenous hormone manipulation. This is despite extensive data demonstrating that genetic and hormonal factors can influence endometriosis progression. Here, we have refined a minimally invasive model of endometriosis using naturally cycling mice (donor and recipient matched for cycle phase) to investigate lesion development in two different strains (C57BL/6 and BALB/c), induced in estrous stages of high and low estrogen (proestrus or estrus, respectively), and with varying amounts of donor endometrial tissue (7.5-40 mg), injected intraperitoneally. The overall probability of developing endometriosis-like lesions was higher in proestrus than estrus, and increased with greater masses of donor tissue. Similarly, the total number of lesions (0-3) increased from 7.5 to 40 mg, and was significantly greater in proestrus C57BL/6 mice but not BALB/cs. The dominant lesion type also differed between mouse strains; C57BL/6 mice were more likely to develop dense-type lesions, whereas BALB/c mice developed a greater proportion of cystic type. These data further support a role for estrogen in the development of endometriosis, and that genetic variance can influence the degree and characteristics of lesions. Our minimally invasive model would be beneficial for studies with outcome measurements particularly sensitive to incisional injury, such as pain, or alterations to sex hormones, including fertility.

Endometrial Intracrinology: Oestrogens, Androgens and Endometrial Disorders

Peripheral tissue metabolism of steroids (intracrinology) is now accepted as a key way in which tissues, such as the endometrium, can utilise inactive steroids present in the blood to respond to local physiological demands and 'fine-tune' the activation or inhibition of steroid hormone receptor-dependent processes. Expression of enzymes that play a critical role in the activation and inactivation of bioactive oestrogens (E1, E2) and androgens (A4, T, DHT), as well as expression of steroid hormone receptors, has been detected in endometrial tissues and cells recovered during the menstrual cycle. There is robust evidence that increased expression of aromatase is important for creating a local microenvironment that can support a pregnancy. Measurement of intra-tissue concentrations of steroids using liquid chromatography⁻tandem mass spectrometry has been important in advancing our understanding of a role for androgens in the endometrium, acting both as active ligands for the androgen receptor and as substrates for oestrogen biosynthesis. The emergence of intracrinology, associated with disordered expression of key enzymes such as aromatase, in the aetiology of common women's health disorders such as endometriosis and endometrial cancer has prompted renewed interest in the development of drugs targeting these pathways, opening up new opportunities for targeted therapies and precision medicine.

Estrogen restricts the apoptosis of endometrial stromal cells by promoting TSLP secretion

Endometriosis (EMS) is a female hormone‑ dependent disease with controversial reports of its etiology and pathogenesis. Apoptosis is particularly important in the human endometrium due to the dynamic cycles of proliferation and shedding. Estrogen possessed antiapoptotic effects on endometrial stromal cells (ESCs), which appears to be exacerbated in women with EMS; however, the underlying mechanism of the antiapoptotic effects of estrogen on ESC remains unknown. The present study aimed to determine whether estrogen regulates the apoptosis of ESCs via thymic stromal lymphopoietin (TSLP) and the associated mechanism. An ELISA was conducted to detect TSLP content in the ESC culture medium treated with estrogen. Subsequently, the early apoptotic rate and expression of B‑cell lymphoma (Bcl‑2) of ESCs were analyzed by flow cytometry in the presence of recombinant human TSLP, anti‑human TSLP neutralizing antibody or estrogen. In the present study, it was reported that ESCs exhibited basal TSLP secretion in the absence of estrogen as reported in previous studies, and that estrogen promoted TSLP secretion of ESCs in a dose‑dependent manner. The results demonstrated that estrogen suppressed the apoptosis of ESCs associated with the promotion of Bcl‑2 expression, which may be partly reversed by inhibiting TSLP. Therefore, the findings of the present study revealed a novel mechanism of estrogen‑dependent apoptotic suppression of ESCs associated with TSLP secretion and Bcl‑2 regulation. Endogenous and estrogen‑induced endometrial TSLP may promote the initiation and development of EMS via the inhibition of apoptosis.

SULFATION PATHWAYS: Contribution of intracrine oestrogens to the aetiology of endometriosis

Endometriosis is an incurable hormone-dependent inflammatory disease that causes chronic pelvic pain and infertility characterized by implantation and growth of endometrial tissue outside the uterine cavity. Symptoms have a major impact on the quality of life of patients resulting in socioeconomic, physical and psychological burdens. Although the immune system and environmental factors may play a role in the aetiology of endometriosis, oestrogen dependency is still considered a hallmark of the disorder. The impact of oestrogens such as oestrone and particularly, oestradiol, on the endometrium or endometriotic lesions may be mediated by steroids originating from ovarian steroidogenesis or local intra-tissue production (intracrinology) dependent upon the expression and activity of enzymes that regulate oestrogen biosynthesis and metabolism. Two key pathways have been implicated: while there is contradictory data on the participation of the aromatase enzyme (encoded by CYP19A1), there is increasing evidence that the steroid sulphatase pathway plays a role in both the aetiology and pathology of endometriosis. In this review, we consider the evidence related to the pathways leading to oestrogen accumulation in endometriotic lesions and how this might inform the development of new therapeutic strategies to treat endometriosis without causing the undesirable side effects of current regimes that suppress ovarian hormone production.

Models including serum CA-125, BMI, cyst pathology, dysmenorrhea or dyspareunia for diagnosis of endometriosis

AIM

To evaluate preoperative levels of CA-125 and HE4 in patients with endometriosis-like symptoms and to construct diagnostic models.

PATIENTS

Prospective case-control study included 124 endometriosis patients and 97 control patients.

MATERIALS & METHODS

Logistic regression was used to construct diagnostic models based on serum biomarker levels and clinical data.

RESULTS

A model with CA-125, BMI, information on cysts and dyspareunia had an area under the curve value of 0.836, sensitivity of 74.0% and specificity of 81.3%. The second model included CA-125, BMI, information on cysts and dysmenorrhea and had an area under the curve value of 0.819, sensitivity of 74.8% and specificity of 79.2%.

CONCLUSION

Constructed models have the potential for noninvasive diagnosis of endometriosis, and might be translated into clinical practice after additional validation.

Estrogen is essential but not sufficient to induce endometriosis

Endometriosis is a common gynaecological disorder of unknown aetiology. Among the several factors, estrogen has been implicated as a causative factor in endometriosis. In the present study using mouse model, we assessed the role of estrogen in the initial implantation and growth of endometrium in ectopic locations. Uterine tissues from green fluorescent protein (GFP) mice were transplanted in to the peritoneum of wild type mice in presence and absence of estrogen. As compared to untreated controls, the implantation of uterine tissue at ectopic locations was higher when estrogen was administered to both host and donor animals. However, this effect was not sustained as lesions regressed within 14 days of treatment. Irrespective of the treatment, peritoneal adipose was the most preferred site of lesion establishment. The lesions did not have typical features of the endometriosis (presence of glands and stroma) even after estrogen treatment and the ectopic tissue underwent regression by apoptosis irrespective of treatment. Since estrogen promotes implantation of endometrial tissue to ectopic locations but failure of these ectopic lesions to grow and sustain even in high estrogenic environment we propose that estrogen is necessary but not sufficient to sustain endometriosis.

Estrogen is an important mediator of mast cell activation in ovarian endometriomas

Endometriosis is an estrogen-dependent disease. Previous research has shown that abnormal enzymes associated with estrogen (E2) metabolism and an increased number of mast cells (MCs) in endometriomas are implicated in the pathogenesis of endometriosis. However, it remains unclear how MCs mediate the role of E2 in endometriosis. Accordingly, we investigated whether E2 was associated with the number of MCs, and the rate of degranulation, in local ovarian endometriomas, as well as the role of E2 on MCs during the pathogenesis of endometriosis. Using enzyme-linked immunosorbent assay and immunohistochemistry, we found that concentrations of E2, and the number and activity of MCs, were significantly higher in ovarian endometriomas than in controls, and that these parameters were correlated with the severity of endometriosis-associated dysmenorrhea. By measuring the release of hexosaminidase, we found that the rate of RBL2H3 cell degranulation increased after E2 treatment. Furthermore, activation of RBL2H3 cells by E2 was found to trigger the release of biologically active nerve growth factor, which promotes neurite outgrowth in PC12 cells and also sensitizes dorsal root ganglion cells via upregulation ofNav1.8and transient receptor potential cation channel (subfamily V member 1) expression levels. When treated with E2, endometriotic cells could promote RBL2H3 cell recruitment by upregulating expression levels of stem cell factor, transforming growth factor-β and monocyte chemoattractant protein-1; these observations were not evident with control endometrial cells. Thus, elevated E2 concentrations may be a key factor for degranulation and recruitment of MCs in ovarian endometriomas, which play a key role in endometriosis-associated dysmenorrhea.

Nam Dia long, a Vietnamese folk formula, induces apoptosis in MCF-7 cells through various mechanisms of action

Background

The holistic approach of traditional medicine renders the identification of its mechanisms of action difficult. Microarray technology provides an efficient way to analyze the complex genome-wide gene expression of cells treated with mixtures of medicinal ingredients. We performed transcriptional profiling of MCF-7 cells treated with Nam Dia Long (NDL), a Vietnamese traditional formula, to explore the mechanism of action underlying the apoptosis inducing effect of this formula reported in a previous study.

Methods

MCF-7 cells were treated with aqueous extracts of NDL at the IC₅₀ concentration for 24, 36 and 48 h. Total RNAs at 24 h and 48 h were subsequently extracted, reverse transcribed and submitted to microarray expression profiling using the Human HT-12 v4.0 Expression Bead Chip (Illumina). Functional analyses were performed using the Database for Annotation, Visualization and Integrated Discovery and the Ingenuity Pathways Analysis. The expression level from selected genes at the three time points were assessed by quantitative real-time RT-PCR and Western blot.

Results

Fifty-four and 601 genes were differentially expressed at 24 and 48 h of NDL treatment, respectively. Genes with altered expression at 24 h were mostly involved in cell responses to xenobiotic stress whereas genes differentially expressed at 48 h were related to endoplasmic reticulum stress, DNA damage and cell cycle control. Apoptosis of NDL treated MCF-7 cells resulted from a combination of different mechanisms including the intrinsic and extrinsic pathways, cell cycle arrest- and oxidative stress-related cell death.

Conclusion

NDL elicited a two-stage response in MCF-7 treated cells with apoptosis as the ultimate result. The various mechanisms inducing apoptosis reflected the complexity of the formula composition.

Electronic supplementary material

The online version of this article (10.1186/s12906-017-2027-2) contains supplementary material, which is available to authorized users.

The Association of Flap Endonuclease 1 Genotypes with the Susceptibility of Endometriosis

BACKGROUND/AIM

Flap endonuclease 1 (FEN1), a protein with multiple functions in genome stability maintenance, is important in cancer prevention. The two functional germline variants of FEN1, rs174538 and rs4246215, regarding cancer susceptibility have been reported in lung, breast, liver, esophageal, gastric, colorectal cancer, glioma and leukemia, but not endometriosis. In this study, we firstly aimed at evaluating the contribution of FEN1 genotypes to endometriosis risk in a representative Taiwan population.

MATERIALS AND METHODS

In total, 153 patients with endometriosis and 636 non-cancer healthy controls were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology.

RESULTS

The genotypes of FEN1 rs174538, but not those of rs4246215, were differently distributed between the endometriosis and control groups. In detail, the AA of FEN1 rs174538 genotypes were significantly less frequently found among endometriosis patients than among controls (odds ratio [OR]=0.43, 95% confidence interval [CI]=0.24-0.78, p=0.0125). The A allele at FEN1 rs174538 was also significantly less frequent among cases than controls (OR=0.65, 95%CI=0.50-0.86, p=0.0021). As for age of first menarche, those with first menarche at the age >12.8 carrying the FEN1 rs174538 AA genotype conferred lower OR of 0.29 (95%CI=0.11-0.78, p=0.0381) for endometriosis. Regarding the full pregnancy status, those without having had a full-term pregnancy carrying the FEN1 rs174538 AA genotype were of lower risk (ORs=0.12, 95%CI=0.03-0.53, p=0.0050).

CONCLUSION

The FEN1 rs174538 A allele is a novel protective biomarker for endometriosis and this genotype may have interactions with age- and hormone-related factors on the development of endometriosis.

Endocrinology Meets Metabolomics: Achievements, Pitfalls, and Challenges

The metabolome, although very dynamic, is sufficiently stable to provide specific quantitative traits related to health and disease. Metabolomics requires balanced use of state-of-the-art study design, chemical analytics, biostatistics, and bioinformatics to deliver meaningful answers to contemporary questions in human disease research. The technology is now frequently employed for biomarker discovery and for elucidating the mechanisms underlying endocrine-related diseases. Metabolomics has also enriched genome-wide association studies (GWAS) in this area by providing functional data. The contributions of rare genetic variants to metabolome variance and to the human phenotype have been underestimated until now.

TNFRp55 deficiency promotes the development of ectopic endometriotic-like lesions in mice

Endometriosis is an inflammatory disease depending on estradiol, with TNF-α being one of the most representative cytokines involved in its pathogenesis. TNF-α acts through its bond to the TNFRp55 and TNFRp75 membrane receptors. The aim of this study was to analyze the effect of the TNFRp55 deficiency on the development of ectopic endometriotic-like lesions. Endometriosis was induced surgically in mice of the C57BL/6 strain, wild type (WT) and TNFRp55-/- (KO). After four weeks, the peritoneal fluid was collected and the lesions were counted, measured with a caliper, removed, weighed, fixed or kept at -80°C. We evaluated the cell proliferation by proliferating cell nuclear antigen (PCNA) immunohistochemistry and apoptosis by TUNEL technique in the ectopic lesions. MMP-2 and MMP-9 activities (factors involved in invasiveness) were measured by zymography in the peritoneal fluid; estradiol and progesterone levels were measured by radioimmunoassay in the lesions and in the peritoneal fluid. We found that in KO animals the mean number of lesions established per mouse, the lesion volume, weight and cell proliferation increased and apoptosis decreased. In addition, the activity of MMP-2 and the estradiol level increased, whereas the progesterone level was not significantly modified. In conclusion, the deficiency of TNFRp55 promoted the establishment and development of endometriosis through an increase in the lesion size and high levels of estradiol which correlate with an increase in the MMP-2 activity. This is evidence of the possible association of the deregulation of the TNFRp55 expression and the survival of the endometriotic tissue in ectopic sites.

Progestins used in endocrine therapy and the implications for the biosynthesis and metabolism of endogenous steroid hormones

Steroidogenesis refers to the de novo synthesis of steroid hormones from cholesterol by a number of sequential enzyme catalysed reactions in the adrenal and the gonads. In addition, circulating steroid hormone precursors are further metabolised in selected peripheral tissues. It has been suggested that the biosynthesis of endogenous steroid hormones can be modulated by progestins, used widely by women in female reproductive medicine. However, as a number of structurally diverse progestins with different pharmacological properties are available, it is possible that these synthetic compounds may vary in their effects on steroidogenesis. This review summarises the evidence indicating that progestins influence the biosynthesis of steroid hormones in the adrenal and gonads, as well as the metabolism of these endogenous hormones in the breast, highlighting the limitations to the current knowledge and directions for future research.

Investigation of anogenital distance as a diagnostic tool in endometriosis

An association between anogenital distance (AGD) and endometriosis has been reported, suggesting that AGD may be a useful clinical tool in endometriosis. The predictive ability of AGD of women in discriminating presence and type of endometriosis was examined. A case-control study was conducted at the University Hospital 'Virgen de la Arrixaca', Murcia, Spain, between 2014 and 2015. A total of 114 participants diagnosed with endometriosis using ultrasound findings and 105 controls were recruited. Two AGD measurements were obtained: one from the anterior clitoral surface to the upper verge of the anus (AGD_AC), and another one from the posterior fourchette to the upper verge of the anus (AGD_AF). Parametric and non-parametric tests andreceiver operator characterstic analyses were used to determine relationships between AGD and presence of endometriosis and subgroups (ovarian endometriomas or deep infiltrating endometriosis [DIE]). The AGD_AF, but not AGD_AC, was associated with presence of endometriomas, DIE (P-values, <0.001-0.02), or both. The highest area under curve (0.91; 95% CI 0.84 to 0.97) was obtained for the DIE subgroup with the AGD_AF measurement, with a sensitivity and specificity of 84.4% and 91.4%, respectively. AGD_AF can therefore efficiently discriminate the presence of DIE and may be a useful clinical tool.

Aberrant PTEN expression in response to progesterone reduces endometriotic stromal cell apoptosis

In some human cancer cells, PTEN (phosphatase and tensin homolog deleted on chromosome 10) is known to regulate autophagy induction positively through the inhibition of PI3K/AKT pathway, leading to the activation of mTOR, a major negative regulator of autophagy. Recent studies reported that PTEN expression is abnormally decreased in endometriotic lesions. In endometriosis, abnormal PTEN expression may contribute to the alteration of endometrial cell autophagy, which may affect apoptosis because endometrial cell autophagy is directly involved in the regulation of apoptosis. To test this hypothesis, we evaluated the involvement of PTEN in the regulation of autophagy induction in human normal endometrial stromal cells (NESCs). In addition, we sought to determine whether aberrant PTEN expression in endometriotic cyst stromal cells (ECSCs) is associated with autophagy dysregulation, and a subsequent decrease in apoptosis. Our results show that PTEN expression was enhanced by progesterone treatment in NESCs. Subsequently, autophagy and apoptosis induction increased through the inhibition of AKT and mTOR activity. This progesterone-induced increase in apoptosis was reversed by the inhibition of autophagy induction using either mifepristone (progesterone receptor modulator) or PTEN inhibitor. In contrast, progesterone had no significant effects on PTEN expression, AKT, mTOR activity, autophagy or apoptosis in ECSCs. Furthermore, in contrast to normal eutopic endometrium, endometriotic tissues have constant PTEN expression, autophagy and apoptosis throughout the menstrual cycle. In conclusion, our results suggest abnormal PTEN expression in response to progesterone was observed in ECSCs, which led to the dysregulation of autophagy induction via AKT/mTOR signalling and a subsequent decrease in apoptosis.

Activin A Stimulates Aromatase via the ALK4-Smad Pathway in Endometriosis

Endometriosis is an estrogen-dependent disease. We previously found that the expression of Activin A was upregulated in the peritoneal fluid of patients with endometriosis. The results of the present study indicated that Activin A induced estradiol secretion and P450arom expression in endometrial stromal cells (ESCs) derived from endometriosis patients. The mechanism of estrogenic synthesis was regulated by the Activin-Smad pathway in endometrial lesions. The data showed that the effect of Activin A on ESCs was partially abrogated by pretreatment with an inhibitor of ALK4 (the type I receptor, ActRIB) and Smad4-siRNA. Cumulatively, these data suggest that Activin A promotes the secretion of estradiol from ESCs by increasing the expression of P450arom via the ALK4-Smad pathway. These findings indicate the ALK4-Smad pathway may promote ectopic lesion survival and development.

The use of Hormone Therapy after Surgery for Endometriosis: An Analysis

Introduction

Estrogen dependence is considered central to the development and progression of endometriosis, which is often viewed as a disease of the premenopausal years, normally regressing after menopause. However, there have been several reports of postmenopausal endometriosis occurring with and without the use of hormone therapy (HT).

Objective

This review aimed to answer the question of whether it is prudent to offer HT for women with a past history of surgical endometriosis. What are the risks? What type of HT should be given?

Methods

A review of the medical literature available in Pubmed, EMBASE, Google scholar, Lilacs, Medline and Cochrane Library databases was performed by selecting articles published in the last ten years, written in any language. The keywords used were endometriosis, menopause, and hormone therapy. In all, 36 articles were found from 2006 to 2016, and their potential relevance to this review was examined. We found 20 literature reviews, 2 retrospective studies, 2 randomized controlled trials and 12 case reports.

Results

There is some risk of endometriosis recurrence after the menopause in patients who receive HT; particularly with estrogen-only therapy.

Conclusions

The existing literature is inadequate to firmly answer our questions. However it is clear that some risk of recurrence exists. Nevertheless, it is suggested that it is reasonable to prescribe HT to women with a history of surgical endometriosis. Recurrences may occur even in the absence of using HT. It is suggested that in women with severe disease the use of estrogen plus progestogen is safer than estrogen alone. Malignant transformation may occur 1% of the time and may be of greater concern with using estrogen alone, warranting close surveillance in all women.

IL15 promotes growth and invasion of endometrial stromal cells and inhibits killing activity of NK cells in endometriosis

Endometriosis (EMS) is associated with an abnormal immune response to endometrial cells, which can facilitate the implantation and proliferation of ectopic endometrial tissues. It has been reported that human endometrial stromal cells (ESCs) express interleukin (IL)15. The aim of our study was to elucidate whether or not IL15 regulates the cross talk between ESCs and natural killer (NK) cells in the endometriotic milieu and, if so, how this regulation occurs. The ESC behaviors in vitro were verified by Cell Counting Kit-8 (CCK-8), Annexin/PI, and Matrigel invasion assays, respectively. To imitate the local immune microenvironment, the co-culture system between ESCs and NK cells was constructed. The effect of IL15 on NK cells in the co-culture unit was investigated by flow cytometry (FCM). In this study, we found that ectopic endometrium from patients with EMS highly expressed IL15. Rapamycin, an autophagy inducer, decreased the level of IL15 receptors (i.e. IL15Rα and IL2Rβ). IL15 inhibits apoptosis and promotes the invasiveness, viability, and proliferation of ESCs. Meanwhile, a co-culture with ESCs led to a decrease in CD16 on NK cells. In the co-culture system, IL15 treatment downregulated the levels of Granzyme B and IFN-γ in CD16+NK cells, NKG2D in CD56dimCD16-NK cells, and NKP44 in CD56brightCD16-NK cells. On the one hand, these results indicated that IL15 derived from ESCs directly stimulates the growth and invasion of ESCs. On the other hand, IL15 may help the immune escape of ESCs by suppressing the cytotoxic activity of NK cells in the ectopic milieu, thereby facilitating the progression of EMS.