Biomarkers in endometriosis: challenges and opportunities

Research Progress of Caspase in Endometriosis

Endometriosis, a common chronic gynecological disease, refers to the presence and proliferation of endometrial tissue in locations other than the uterine cavity. Approximately 6 to 10% of the population of women of childbearing age are known to have endometriosis; the most common clinical signs are pelvic pain and infertility. Although endometriosis is a benign disease, it exhibits some typical features of malignant tumors, such as proliferation, invasion, metastasis, and recurrence. Endometriosis is considered a chronic, inflammatory, and estrogen-dependent disease, and multiple factors contribute to its occurrence and development. In recent years, increasing attention has been given to the role of apoptosis in the pathogenesis of this disease. Some researchers believe that spontaneous apoptosis of the endometrium is critical in maintaining its normal structure and function, and abnormal apoptosis can promote the occurrence and development of endometriosis. Inflammation is another likely process in the pathogenesis of endometriosis. Inflammation mediates the adhesion, proliferation, differentiation, and invasion of ectopic lesions of endometriosis, primarily by regulating the function of immune cells and increasing the level of proinflammatory cytokines in body fluids. The ultimate initiators of apoptosis and inflammatory cell death (pyroptosis) are the caspase family proteases. In this article, we review the progress in recent years in caspase function as well as the possible role of these enzymes in the pathogenesis of endometriosis, indicating potential treatment strategies.

Beyond physical pain: A large-scale cohort study on endometriosis trends and mental health correlates

BACKGROUND

This study investigates the increased prevalence of endometriosis in Israel and its association with psychiatric comorbidities, focusing on the timing of psychiatric diagnoses in relation to endometriosis diagnosis.

METHODS

Employing a retrospective cohort analysis, we reviewed data from 1,291,963 patients in a large scale medical database, identifying 24,259 cases (1.88%) of endometriosis. The analysis included demographic details, ICD-10 diagnoses of endometriosis and mental health conditions, and medication use patterns.

RESULTS

A marked rise in endometriosis diagnosis was observed, particularly among women born between 1973 and 1978. Those with endometriosis were more likely to have psychiatric disorders-such as mood disorders, anxiety, PTSD, and eating disorders-than the control group, with the majority of psychiatric diagnoses occurring prior to endometriosis detection, except for PTSD. The study also highlighted significant sociocultural and socioeconomic disparities in endometriosis diagnosis, suggesting barriers to healthcare access and the influence of cultural factors. Limitations include potential biases from the retrospective design and the specific context of Israel's healthcare system, which may limit generalizability.

CONCLUSIONS

The significant rise in endometriosis and its strong association with psychiatric comorbidities, predominantly preceding the diagnosis of endometriosis, underscores the necessity for integrated care approaches. The disparities in diagnosis rates call for culturally sensitive healthcare practices and early psychiatric interventions.

A systematic review of the mechanistic actions of microRNAs within integrated traditional Chinese medicine and western medical treatment for endometriosis

Endometriosis (EM), also known as Zhengjia in traditional Chinese medicine, is a common disease that significantly impacts women's health. An integrated treatment approach combining traditional Chinese medicine (TCM) and western medicine has demonstrated significant clinical efficacy in the management of this condition. Specifically, it has been effective in addressing blood circulation and other diseases. MicroRNAs (miRNAs), which are molecules important in gene regulation, have been implicated in various physiologic and pathologic processes. In this review, we systematically summarized the potential mechanisms underlying the integrated EM treatment, with a focus on the role of microRNAs (miRNAs). Current research suggests that integrated TCM and western medicine treatment may exert their therapeutic effects on EM by influencing the expression of miRNAs. Through miRNA modulation, such a treatment approach may inhibit the growth of ectopic lesions and alleviate clinical symptoms. This review will shed light on the specific miRNAs that have been implicated in the integrated treatment of EM, as well as their potential mechanisms of action. By consolidating the existing evidence, we aim to provide clinicians and researchers with a clearer understanding of the therapeutic benefits of the integrated approach and potentially identify new avenues for improving clinical treatment outcomes. Ultimately, this review will contribute to the growing body of knowledge in this field, providing a basis for further research and the development of more targeted and efficient treatment strategies for EM.

Interactions between miRNAs and the Wnt/β-catenin signaling pathway in endometriosis

Endometriosis is a disease characterized by the ectopic growth of endometrial tissue (glands and stroma) outside the confines of the uterus and often involves vital organs such as the intestines and urinary system. Endometriosis is considered a refractory disease owing to its enigmatic etiology, propensity for recurrence following conservative or surgical interventions, and the absence of radical treatment and long-term management. In recent years, the incidence of endometriosis has gradually increased, rendering it a pressing concern among women of childbearing age. A more profound understanding of its pathogenesis can significantly improve prognosis. Recent research endeavors have spotlighted the molecular mechanisms by which microRNAs (miRNAs) regulate the occurrence and progression of endometriosis. Many miRNAs have been reported to be aberrantly expressed in the affected tissues of both patients and animal models. These miRNAs actively participate in the regulation of inflammatory reactions, cellular proliferation, angiogenesis, and tissue remodeling. Their capacity to modulate crucial signaling pathways, such as the Wnt/β-catenin signaling pathway, reinforces their potential utility as diagnostic markers or therapeutic agents for endometriosis. In this review, we provide the latest insights into the role of miRNAs that interact with the Wnt/β-catenin pathway to regulate the biological behaviors of endometriosis cells and disease-related symptoms, such as pain and infertility. We hope that this review will provide novel insights and promising targets for innovative therapies addressing endometriosis.

Visualized peritoneal fluid variation in adolescents and young adults with endometriosis: is there more to it?

Background

Peritoneal fluid is a medium for endometriosis-associated biomarker discovery from which the local peritoneal environment and pathophysiologic pathways are often inferred. Therefore, we evaluated the associations between peritoneal fluid color and volume at time of endometriosis-related laparoscopic surgery with patient characteristics, endometriosis type and lesion location in adolescents and young adults with endometriosis.

Methods

We conducted a cross-sectional analysis among 545 patients undergoing surgery for endometriosis who enrolled in the Women's Health Study: from Adolescence to Adulthood cohort study. Patient characteristics, surgically visualized endometriosis phenotypes, and gross characteristics of peritoneal fluid were collected in compliance with World Endometriosis Research Foundation Endometriosis Phenome and Biobanking Harmonization Project (EPHect) tools. Chi-square or Fisher's exact tests were applied to test for differences across categories.

Results

Most of the patients were adolescents or young adults (86% age <25 years) of white race (89%), with only superficial peritoneal lesions and rASRM stage = I/II observed at surgery (both 95%). We observed variation in peritoneal fluid color across different menstrual cycle phases at time of surgery (p = 0.006). Among those who were cycling at time of surgery, endometriosis patients with red peritoneal fluid were most likely to be in the proliferative phase (49%) compared to the secretory phase (27%), while those with yellow or orange peritoneal fluid were most likely to be in the secretory phase (57% and 86% respectively). Yellow color was significantly less common in those taking combined oral contraceptives but much more common with progesterone only formulation exposure (p = 0.002). Peritoneal fluid volume did not differ by cycle phase but was more likely to be low (≤6 ml) for those exposed to hormones at time of surgery (p = 0.01). Those with acyclic pelvic pain were less likely to have red peritoneal fluid (p = 0.001) but had greater volume (p = 0.02) compared to those without.

Conclusion

Our findings highlight the importance of accounting for menstrual cycle phase and hormonal exposures when designing research using peritoneal fluid samples and inferring from biomarker results intended to advance our understanding of endometriosis and associated symptom pathophysiology.

Role of cystatin C levels as an inflammatory marker in predicting endometriosis

OBJECTIVE

Endometriosis is a common chronic inflammatory disease associated with infertility and pelvic pain. Diagnosis is based on the appearance of endometriotic lesions at the time of surgery. Our study aimed to determine whether cystatin C can be used as a predictor of endometriosis and to investigate its potential role in doing so.

METHODS

The study included 45 patients with endometriosis between the ages of 18 and 40 years whose pathology results were compatible with endometriosis and were operated on, and a control group of 45 healthy women. These two groups were compared in terms of serum cystatin C levels, demographic-clinical characteristics, operation results, and other laboratory values.

RESULTS

The cystatin C and hs-CRP levels of the endometriosis patients were found to be significantly higher than the control subjects (p<0.005). Whether the endometriosis disease could be detected for serum cystatin C levels was determined by the receiver operating characteristic analysis and the most appropriate positive cutoff value for cystatin C was found to be 5.14 ng/mL (86.7% sensitivity and 77.8% specificity). In the linear regression analysis, it was observed that the probability of endometriosis increased 2.5 times when cystatin C levels increased above the threshold value of 5.14 ng/mL (OR: 2.5; 95%CI 2.24-2.76).

CONCLUSION

Our study shows that the serum cystatin C levels can be used as a guide for diagnosis in patients with advanced endometriosis. However, more research is needed to prove its reliability and accuracy in order to put it into practice.

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

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

Brain-derived neurotrophic factor and nerve growth factor expression in endometriosis: A systematic review and meta-analysis

Endometriosis is diagnosed by laparoscopic surgery. The availability of biomarkers can help understand the pathophysiology and aid in the diagnosis of the condition. In this context, this review aimed to examine levels of expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are increased amongst patients with endometriosis and if they can serve as a potential biomarker. PubMed, CENTRAL, Scopus, Web of Science, and Embase databases were searched for studies comparing BDNF or NGF levels amongst endometriosis patients and controls. Data were pooled for serum and tissue levels of BDNF and NGF. Ten fulfilled the inclusion criteria. On comparing BDNF levels, it was noted that endometrial tissue had significantly higher expression of BDNF levels as compared to controls (SMD: 1.73 95% CI: 0.64, 2.82 I2 = 89%). Similarly, the meta-analysis found significantly higher serum levels of BDNF in endometriosis patients as compared to controls (SMD: 1.66 95% CI: 0.73, 2.59 I2 = 95%). Pooled analysis showed significantly increased levels of NGF in endometrial tissue as compared to controls (SMD: 4.15 95% CI: 0.11, 8.18 I2 = 98%) but with unstable results on sensitivity analysis. Only one study showed higher levels of NGF in serum amongst endometriosis patients. Limited data shows higher expression of BDNF in endometrial lesions and increased serum levels of BDNF in endometriosis patients. Similar results were noted for NGF but with very scarce data. Further research is needed to establish BDNF and NGF as suitable biomarkers for the disease.

MiR-17-5p promoter methylation regulated by DNA methyltransferase 3 beta (DNMT3B) expedites endometriosis via the Krüppel-like factor 12 (KLF12)/Wnt/β-catenin axis

Endometriosis (EM) is a common chronic disease in women with a high incidence, and aberrant DNA methylation and circulating endometrial cells (CECs) have been reported to be involved in the development of EM. However, the underlying mechanisms by which DNA methylation regulates EM progression have not been fully elucidated. In our study, we demonstrated that the DNA methyltransferase 3 beta (DNMT3B)-mediated DNA methylation modification enhanced EM progression through regulating miR-17-5p/KLF12/Wnt/β-catenin axis. In detail, expression levels of miR-17-5p were significantly downregulated in EM tissues and serums, and we found that DNMT3B elevated the methylation modification of the miR-17-5p promoter, thereby suppressing the expression of miR-17-5p. Subsequently, functional experiments showed that silencing DNMT3B inhibited cell viability and epithelial-mesenchymal transition (EMT) and promoted cell apoptosis in CECs, whereas this effect could be reversed by knocking down miR-17-5p. Besides, overexpression of miR-17-5p repressed EM progression in vivo. Moreover, we found that miR-17-5p could target negative regulation of Krüppel-like factor 12 (KLF12) and KLF12 overexpression could rescue the effect of over-miR-17-5p. Besides, miR-17-5p was able to suppress the Wnt/β-catenin signaling pathway, and blocked Wnt/β-catenin pathway by XAV-939 reversed the influence of knockdown of miR-17-5p. Overall, our data indicated that DNMT3B-mediated DNA methylation leading to miR-17-5p inhibition exacerbated the process of EM by targeting KLF12/Wnt/β-catenin axis, which provided a new perspective on targeted therapies for EM.

Abnormal expression of fission and fusion genes and the morphology of mitochondria in eutopic and ectopic endometrium

Mitochondria play a pivotal role in physiological and metabolic function of the cell. Mitochondrial dynamics orchestrate mitochondrial function and morphology, involving fission and fusion as well as ultrastructural remodeling. Mounting evidence unravels the close link between mitochondria and endometriosis. However, how mitochondrial architecture changes through fission and fusion in eutopic and ectopic tissues of women with ovarian endometriosis remains unknown. We detected the expression of fission and fusion genes and the morphology of mitochondria in eutopic and ectopic endometrium in ovarian endometriosis. The results showed that the expression of DRP1 and LCLAT1 was upregulated in eutopic endometrial stromal cells (ESCs), and the expression of DRP1, OPA1, MFN1, MFN2, and LCLAT1 was significantly downregulated in ectopic ESCs, and reduced number of mitochondria, wider cristae width and narrower cristae junction width was observed, but there was no difference in cell survival rate. The altered mitochondrial dynamics and morphology might, respectively, provide an advantage for migration and adhesion in eutopic ESCs and be the adaptive response in ectopic endometrial cells to survive under hypoxic and oxidative stress environment.

Development and Validation of an Endometriosis Diagnostic Method Based on Serum Biomarkers and Clinical Variables

Endometriosis affects more than 10% of women of reproductive age, significantly impacting their quality of life. Diagnosis typically takes 4 to 11 years from symptom onset. The gold standard for diagnosing this disease, laparoscopy, is invasive, contributing to this delay in diagnosis. Two studies were conducted to develop a diagnostic test based on the combination of serum biomarkers and clinical variables. Study 1, the development study, aimed to: (i) confirm the ability of CA125, BDNF and clinical variables to differentiate between cases and controls, and (ii) develop a diagnostic algorithm based on these results. Study 2 validated the clinical performance of the developed in vitro diagnostic (IVD) test in diagnosing endometriosis. Serum samples and clinical variables extracted from psychometric questionnaires were obtained from the Oxford Endometriosis CaRe Centre biobank (UK). Case/control classification was performed based on laparoscopy and histological verification of the excised lesions. Studies 1 and 2 included n = 204 and n = 79 patients, respectively. Study 1 found a statistically significant difference between cases and controls for levels of both biomarkers. Of the assessed clinical variables from the patients' medical histories, six were found to be significantly different between endometriosis cases and controls. CA125, BDNF and these six clinical variables were combined into a multivariable prediction model. In Study 2, the IVD test demonstrated sensitivity and specificity values of 46.2% (25.5-66.8%) and 100% (86.7-100%), respectively. Due to its high specificity, this IVD test is a simple and accurate rule-in test for early disease identification, even in the presence of non-specific symptoms.

Exploring Patient Adherence to Post-Surgical Follow-Up in Pelvic Endometriosis

Endometriosis is a significant cause of disability that affects 5-10% of reproductive-aged women. Laparoscopy with histological confirmation is the gold standard in establishing the diagnosis as therapeutic management surgery is addressed to a certain category of patients. The objective of this study was to assess patient adherence to follow-up after surgery for endometriosis as the primary endpoint, pain symptoms, quality of life, mental health, and fertility as the secondary endpoints. We have analyzed patients' adherence to follow-up after surgery for endometriosis after 1, 3, 5, and 7 years. Out of the 2538 total number of surgeries, 453 patients replied just to the first questionnaire (group A), 528 to the first and second (group B), and only 356 carried out the entire follow-up schedule. General health was significantly lower for group A (46.6 vs. 56.4) but with no statistical difference in the post-surgical improvement in both groups. Pain level score improvement was lower for group A (10.5 vs. 18.8), which is statistically significant. In this light, laparoscopy still remains the gold standard in diagnosis only. Furthermore, no malignancy was discovered. The mental component was improved by laparoscopy based on SF-36 in group B. Studies on patient preference for surgery versus alternative treatment are needed.

Endometriosis and the Temporomandibular Joint-Preliminary Observations

(1) Background: The complete picture of the disease is not fully recognized and extends far beyond the pelvis. The disease's impacts lead to systemic inflammation, in turn resulting in sensitization to pain. The aim of this study was to check whether statistical correlations exist in women with endometriosis with regard to their experience of pain: headache, pelvic pain, temporomandibular joint pain, along with teeth clenching and the treatment of the disease. We constructed contingency tables, followed by Pearson's chi-square test and Cramer's V coefficient values. (2) Methods: A survey was conducted among 128 women aged 33.43 ± 5.79 with a diagnosis of endometriosis (disease duration 6.40 ± 5.88 years). (3) Results: There was a correlation between the occurrence of pain on the right and left sides of the pelvis and pain on the right and left sides of the temporomandibular joint, p-value = 0.0397, V = 0.2350, and between the presence of pelvic pain and the treatment of endometriosis, p-value = 0.0104, V = 0.3709, and between the presence of pain outside the pelvis and the treatment of endometriosis, p-value = 0.0311, V = 0.4549. There was a highly significant correlation between teeth clenching and temporomandibular joint pain, p-value = 0.0005, V = 0.3695. (4) Conclusions: The study revealed a correlation between pelvic endometriosis symptoms and symptoms in the temporomandibular joint.

Epigenetics, endometriosis and sex steroid receptors: An update on the epigenetic regulatory mechanisms of estrogen and progesterone receptors in patients with endometriosis

Endometriosis is a benign gynecological disease affecting ∼10% of reproductive-aged women and is defined as the presence of endometrial glands and stroma outside the uterine cavity. Endometriosis can cause a variety of health problems, from pelvic discomfort to catamenial pneumothorax, but it's mainly linked with severe and chronic pelvic pain, dysmenorrhea, and deep dyspareunia, as well as reproductive issues. The pathogenesis of endometriosis involves an endocrine dysfunction, with estrogen dependency and progesterone resistance, and inflammatory mechanism activation, together with impaired cell proliferation and neuroangiogenesis. The present chapter aims to discuss the main epigenetic mechanisms related to estrogen receptors (ERs) and progesterone receptors (PRs) in patients with endometriosis. There are numerous epigenetic mechanisms participating in endometriosis, regulating the expression of the genes encoding these receptors both indirectly, through the regulation of transcription factors, and directly, through DNA methylation, histone modifications, micro RNAs and long noncoding RNAs. This represents an open field of investigation, which may lead to important clinical implications such as the development of epigenetic drugs for the treatment of endometriosis and the identification of specific and early biomarkers for 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.

Current Role of Modern Chromatography with Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy in the Investigation of Biomarkers of Endometriosis

Endometriosis has a wide range of clinical manifestations, and the disease course is unpredictable, making the diagnosis a challenging task. Despite significant advances in the pathophysiology of endometriosis and various proposed theories, the exact etiology is not fully understood and is still unknown. The most commonly used biomarker of endometriosis is CA-125, however, it is nonspecific and is applied for cancers diagnosis. Therefore, the development of reliable noninvasive diagnostic tests for the early diagnosis of endometriosis remains one of the top priorities. Omics technologies are very promising approaches for constructing diagnostic models and biomarker discovery. Their use can greatly facilitate the study of such a complex disease as endometriosis. Nowadays, powerful analytical platforms commonly used in omics, such as gas and liquid chromatography with mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy, have proven to be a promising tools for biomarker discovery. The aim of this review is to summarize the various features of the analytical approaches, practical challenges and features of gas and liquid chromatography with MS and NMR spectroscopy (including sample processing protocols, technological advancements, and methodology) used for profiling of metabolites, lipids, peptides and proteins in physiological fluids and tissues from patients with endometriosis. In addition, this report devotes special attention to the issue of how comprehensive analyses of these profiles can effectively contribute to the study of endometriosis. The search query included reports published between 2012 and 2022 years in PubMed, Web-of-Science, SCOPUS, Science Direct.

Identification and Analysis of Potential Immune-Related Biomarkers in Endometriosis

Background

Endometriosis is an inflammatory gynecological disease leading to deep pelvic pain, dyspareunia, and infertility. The pathophysiology of endometriosis is complex and depends on a variety of biological processes and pathways. Therefore, there is an urgent need to identify reliable biomarkers for early detection and accurate diagnosis to predict clinical outcomes and aid in the early intervention of endometriosis. We screened transcription factor- (TF-) immune-related gene (IRG) regulatory networks as potential biomarkers to reveal new molecular subgroups for the early diagnosis of endometriosis.

Methods

To explore potential therapeutic targets for endometriosis, the Gene Expression Omnibus (GEO), Immunology Database and Analysis Portal (ImmPort), and TF databases were used to obtain data related to the recognition of differentially expressed genes (DEGs), differentially expressed IRGs (DEIRGs), and differentially expressed TFs (DETFs). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed on the DETFs and DEIRGs. Then, DETFs and DEIRGs were further validated in the external datasets of GSE51981 and GSE1230103. Then, we used quantitative real-time polymerase chain reaction (qRT-PCR) to verify the hub genes. Simultaneously, the Pearson correlation analysis and protein-protein interaction (PPI) analyses were used to indicate the potential mechanisms of TF-IRGs at the molecular level and obtain hub IRGs. Finally, the receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic value of the hub IRGs.

Results

We screened a total of 94 DETFs and 121 DEIRGs in endometriosis. Most downregulated DETFs showed decreased expression in the endometria of moderate/severe endometriosis patients. The top-ranked upregulated DEIRGs were upregulated in the endometra of infertile women. Functional analysis showed that DETFs and DEIRGs may be involved in the biological behaviors and pathways of endometriosis. The TF-IRG PPI network was successfully constructed. Compared with the control group, high C3, VCAM1, ITGB2, and C3AR1 expression had statistical significance in endometriosis among the hub DEIRGs. They also showed higher sensitivity and specificity by ROC analysis for the diagnosis of endometriosis. Finally, compared with controls, C3 and VCAM1 were highly expressed in endometriosis tissue samples. In addition, they also showed high specificity and sensitivity for diagnosing endometriosis.

Conclusion

Overall, we discovered the TF-IRG regulatory network and analyzed 4 hub IRGs that were closely related to endometriosis, which contributes to the diagnosis of endometriosis. Additionally, we verified that DETFs or DEIRGs were associated with the clinicopathological features of endometriosis, and external datasets also confirmed the hub IRGs. Finally, C3 and VCAM1 were highly expressed in endometriosis tissue samples compared with controls and may be potential biomarkers of endometriosis, which are helpful for the early diagnosis of endometriosis.

Oocyte-Secreted Serum Biomarkers GDF9 and BMP15 in Women with Endometriosis

Oocyte-secreted growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are critical paracrine regulators of female fertility. Recent studies demonstrated that serum concentrations are associated with the number of oocytes retrieved during IVF, and therefore potential clinical use as biomarkers. However, it is unknown if the presence of endometriosis affects serum GDF9 or BMP15. An exploratory case–control study was prospectively performed on 60 women who underwent laparoscopy between April 2017 and August 2018 at two hospitals. GDF9 and BMP15 were measured by validated immunoassays in pre-operative serum samples. Data were analysed relative to laparoscopic assessment of endometriosis and staging. There were 35 women with confirmed laparoscopic diagnosis of endometriosis and 25 controls with no evidence of endometriosis at laparoscopy. GDF9 was detectable in 40% of controls and 48% of cases. There was no difference in median GDF9 concentrations between controls (20.0 pg/ml, range 20.0–2504 pg/ml) and cases (20.0 pg/ml, range 20.0–2963 pg/ml). BMP15 was detectable in 48% of controls and 58% of cases, with no difference in median concentrations between controls (26.5 pg/ml, range 24.0–1499 pg/ml) and cases (24.0 pg/ml, range 24.0–796 pg/ml). Furthermore, there were no significant differences in the proportion of detectable samples or concentrations of GDF9 or BMP15 with differing severities of endometriosis. In conclusion, serum concentrations of oocyte-secreted factors, GDF9 and BMP15 did not differ between control patients and patients with endometriosis. For clinical application in reproductive medicine, GDF9 and BMP15 serum biomarker quantitation is unlikely to be aberrant in the presence of endometriosis.

Pathophysiology, diagnosis, and management of endometriosis

Endometriosis affects approximately 190 million women and people assigned female at birth worldwide. It is a chronic, inflammatory, gynecologic disease marked by the presence of endometrial-like tissue outside the uterus, which in many patients is associated with debilitating painful symptoms. Patients with endometriosis are also at greater risk of infertility, emergence of fatigue, multisite pain, and other comorbidities. Thus, endometriosis is best understood as a condition with variable presentation and effects at multiple life stages. A long diagnostic delay after symptom onset is common, and persistence and recurrence of symptoms despite treatment is common. This review discusses the potential genetic, hormonal, and immunologic factors that lead to endometriosis, with a focus on current diagnostic and management strategies for gynecologists, general practitioners, and clinicians specializing in conditions for which patients with endometriosis are at higher risk. It examines evidence supporting the different surgical, pharmacologic, and non-pharmacologic approaches to treating patients with endometriosis and presents an easy to adopt step-by-step management strategy. As endometriosis is a multisystem disease, patients with the condition should ideally be offered a personalized, multimodal, interdisciplinary treatment approach. A priority for future discovery is determining clinically informative sub-classifications of endometriosis that predict prognosis and enhance treatment prioritization.

A syngeneic inoculation mouse model of endometriosis that develops multiple comorbid visceral and cutaneous pain like behaviours

ABSTRACT

Endometriosis is a chronic and debilitating condition, commonly characterised by chronic pelvic pain (CPP) and infertility. Chronic pelvic pain can be experienced across multiple pelvic organs, with comorbidities commonly effecting the bowel, bladder, and vagina. Despite research efforts into endometriosis pathophysiology, little is known about how endometriosis induces CPP, and as such, therapeutic interventions are lacking. The aim of this study was to characterise a syngeneic mouse model of endometriosis that mimics naturally occurring retrograde menstruation, thought to precede endometriosis development in patients, and determine whether these mice exhibit signs of CPP and altered behaviour. We characterised the development of endometriosis over 10 weeks following uterine tissue inoculation, measured in vivo and ex vivo hypersensitivity to mechanical stimuli across multiple visceral organs, and assessed alterations in animal spontaneous behaviour. We confirmed that inoculated uterine horn tissue formed into endometriosis lesions throughout the peritoneal cavity, with significant growth by 8 to 10 weeks post inoculation. Additionally, we found that mice with fully developed endometriosis displayed hypersensitivity evoked by (1) vaginal distension, (2) colorectal distension, (3) bladder distension, and (4) cutaneous thermal stimulation, compared to their sham counterparts. Moreover, endometriosis mice displayed alterations in spontaneous behaviour indicative of (5) altered bladder function and (6) anxiety. This model creates a foundation for mechanistical studies into the diffuse CPP associated with endometriosis and the development of targeted therapeutic interventions to improve the quality of life of women with endometriosis.

Endometriosis biomarkers of the disease: an update

PURPOSE OF REVIEW

Endometriosis is a complex benign gynaecologic condition with heterogenous presentations and a large impact on the global healthcare system and on the quality of life for millions of women. Currently, the gold standard for diagnosis involves direct visualization of lesions during surgery confirmed by histopathological diagnosis, resulting in an average delay in its initial diagnosis of 8-10 years. Therefore, the search for noninvasive diagnostic testing options has been subject to a large body of research.

RECENT FINDINGS

Multiple potential biomarkers have been explored for noninvasive testing for endometriosis, including glycoproteins, inflammatory cytokines, immunological molecules, angiogenesis markers, hormones, micro RNAs (miRNAs), proteomics, metabolomics, genomics and the microbiome.

SUMMARY

Although there are challenges to consider, areas for real promise and advancement in the noninvasive diagnosis of endometriosis are currently being explored with real promise in the area of miRNAs, proteomics, metabolomics, genomics and the microbiome.

ATR-IR Spectroscopy Application to Diagnostic Screening of Advanced Endometriosis

Endometriosis is one of the most common gynecological diseases among young women of reproductive age. Thus far, it has not been possible to define a parameter that is sensitive and specific enough to be a recognized biomarker for diagnosing this disease. Nonspecific symptoms of endometriosis and delayed diagnosis are impulses for researching noninvasive methods of differentiating endometriosis from other gynecological disorders. We compared three groups of individuals in our research: women with endometriosis (E), patients suffering from other gynecological disorders (nonendometriosis, NE), and healthy women from the control group (C). Partial least squares discriminant analysis (PLS-DA) models were developed based on selected serum biochemical parameters, specific regions of the serum’s infrared attenuated total reflectance (FTIR ATR) spectra, and combined data. Incorporating the spectral data into the models significantly improved differentiation among the three groups, with an overall accuracy of 87.5%, 97.3%, and 98.5%, respectively. This study shows that infrared spectroscopy and discriminant analysis can be used to differentiate serum samples among women with advanced endometriosis, women without this disease, i.e., healthy women, and, most importantly, also women with other benign gynecological disorders.

MicroRNAs in the Regulation of Endometrial Receptivity for Embryo Implantation

Development of endometrial receptivity is crucial for successful embryo implantation and pregnancy initiation. Understanding the molecular regulation underpinning endometrial transformation to a receptive state is key to improving implantation rates in fertility treatments such as IVF. With microRNAs (miRNAs) increasingly recognized as important gene regulators, recent studies have investigated the role of miRNAs in the endometrium. Studies on miRNAs in endometrial disorders such as endometriosis and endometrial cancer have been reviewed previously. In this minireview, we aim to provide an up-to-date knowledge of miRNAs in the regulation of endometrial receptivity. Since endometrial remodelling differs considerably between species, we firstly summarised the key events of the endometrial cycle in humans and mice and then reviewed the miRNAs identified so far in these two species with likely functional significance in receptivity establishment. To date, 29 miRNAs have been reported in humans and 15 miRNAs in mice within various compartments of the endometrium that may potentially modulate receptivity; miRNAs regulating the Wnt signalling and those from the let-7, miR-23, miR-30, miR-200 and miR-183 families are found in both species. Future studies are warranted to investigate miRNAs as biomarkers and/or therapeutic targets to detect/improve endometrial receptivity in human fertility treatment.

Antibody Arrays Identified Cycle-Dependent Plasma Biomarker Candidates of Peritoneal Endometriosis

Endometriosis is an estrogen-dependent inflammatory disease affecting women in their reproductive age. Due to non-specific symptoms, women with endometriosis are often misdiagnosed or are accurately diagnosed only after several years. Diagnosis of peritoneal endometriosis is especially challenging and relies only on laparoscopic surgery. To date, different molecules have been proposed as potential non-invasive biomarkers of endometriosis; however, none have been confirmed as clinically useful. Therefore, this study aimed to discover novel plasma biomarker candidates for peritoneal endometriosis using an antibody array platform. This study included patients with endometriosis-like symptoms characterized by the absence (controls) or presence of peritoneal endometriosis (cases) after laparoscopic surgery and histological evaluation. Patients were further divided into secretory and proliferative groups, according to the phase of their menstrual cycle. Their plasma samples were collected and analyzed on an antibody array platform targeting more than 1350 proteins with over 1820 antibodies. In the proliferative group, the analysis revealed three differential proteins between cases and controls: ITB3, ITA2B2, and ACVL-1. In the secretory group, none of the examined proteins reached the log-fold change (logFC) and significance thresholds simultaneously. The potential of the identified differential proteins as plasma biomarker candidates for peritoneal endometriosis should be evaluated on a larger cohort, and their role in endometriosis should be investigated in further studies.

Expression of lncRNA NEAT1 in endometriosis and its biological functions in ectopic endometrial cells as mediated via miR-124-3p

BACKGROUND

Endometriosis (EM) is a gynecological disease that poses severe health risks to women, although its pathogenesis has yet to be fully elucidated. It has been shown that long non-coding RNAs (lncRNAs) are closely associated with EM initiation and have a role in the development of this disease. Previous studies exploring the expression of the lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) have shown that this lncRNA functions as a tumor promoter in endometrial cancer. However, its exact mechanism of action in EM remains unclear.

OBJECTIVE

This report was designed to illustrate the potential molecular mechanisms of lncRNA NEAT1 on EM.

METHODS

Endometrial tissues were extracted from EM model rats and patients with EM. Hematoxylin and eosin staining was applied to detect the morphological changes that occurred in rats after construction of the model. Endometrial stromal cells (ESCs) were extracted from either ectopic endometrium (EC) or eutopic endometrium (EU) tissues from patients with EM. LncRNA NEAT1 and miR-124-3p expression in EM tissues and cells were subsequently evaluated by reverse transcription-quantitative (RT-q)PCR analysis. MTT assay, flow cytometric analysis, western blot assay and Transwell assay were then employed to examine the effect of NEAT1 and miR-124-3p on EC-ESC proliferation, apoptosis, migration and invasion, respectively. The targeted relationship between lncRNA NEAT1 and miR-124-3p was subsequently confirmed by dual-luciferase and co-transfection assays.

RESULTS

MiR-124-3p was identified as a target of NEAT1, and could be negatively regulated by NEAT1 in EC-ESCs. The expression level of NEAT1 was evidently increased, whereas that of miR-124-3p was decreased, in the EM in vivo model, EM tissues and EC-ESCs from patients with EM. The loss-of-function assays further established that silencing of NEAT1 could inhibit EC-ESC proliferation, migration, and invasion, but it led to the promotion of apoptosis via targeting miR-124-3p.

CONCLUSIONS

NEAT1 is significantly upregulated in EM, promoting malignant behavior in EM through targeting miR-124-3p expression.

Medical and Behavioral Aspects of Adolescent Endometriosis: A Review of the Literature

The majority of young women will experience discomfort associated with menstrual cycles and miss out on education and social opportunities. Endometriosis, the presence of endometrial glands and stroma outside of uterus, is the most common cause of secondary dysmenorrhea and characterized by pain despite treatment with nonsteroidal anti-inflammatory drugs and hormonal agents. The true prevalence of adolescent endometriosis is not clear. Delay in diagnosis leads to persistent pain, affects quality of life, and potentially contributes to disease progression and subfertility. A laparoscopic diagnosis is the gold standard, but the surgical appearance may differ from adults, as endometriotic lesions are usually red or clear, making their identification a challenge for gynecologists who are unexperienced with endometriosis in adolescents. A personalized medical–surgical treatment is regarded as the most effective therapeutic strategy to achieve remission of symptoms, suppress disease progression, and protect future fertility. Studies have demonstrated how adolescent endometriosis negatively affects patients’ quality of life and psychosocial functioning. Development of therapeutic interventions targeting psychosocial function and quality of life is imperative for adolescent patients.

Identification of Altered Evoked and Non-Evoked Responses in a Heterologous Mouse Model of Endometriosis-Associated Pain

The aim of this study was to develop and refine a heterologous mouse model of endometriosis-associated pain in which non-evoked responses, more relevant to the patient experience, were evaluated. Immunodeficient female mice (N = 24) were each implanted with four endometriotic human lesions (N = 12) or control tissue fat (N = 12) on the abdominal wall using tissue glue. Evoked pain responses were measured biweekly using von Frey filaments. Non-evoked responses were recorded weekly for 8 weeks using a home cage analysis (HCA). Endpoints were distance traveled, social proximity, time spent in the center vs. outer areas of the cage, drinking, and climbing. Significant differences between groups for von Frey response, climbing, and drinking were detected on days 14, 21, and 35 post implanting surgery, respectively, and sustained for the duration of the experiment. In conclusion, a heterologous mouse model of endometriosis-associated evoked a non-evoked pain was developed to improve the relevance of preclinical models to patient experience as a platform for drug testing.

Clinical Management of Chronic Pelvic Pain in Endometriosis Unresponsive to Conventional Therapy

Background: Although several treatments are currently available for chronic pelvic pain, 30–60% of patients do not respond to them. Therefore, these therapeutic options require a better understanding of the mechanisms underlying endometriosis-induced pain. This study focuses on pain management after failure of conventional therapy. Methods: We reviewed clinical data from 46 patients with endometriosis and chronic pelvic pain unresponsive to conventional therapies at Puerta de Hierro University Hospital Madrid, Spain from 2018 to 2021. Demographic data, clinical and exploratory findings, treatment received, and outcomes were collected. Results: Median age was 41.5 years, and median pain intensity was VAS: 7.8/10. Nociceptive pain and neuropathic pain were identified in 98% and 70% of patients, respectively. The most common symptom was abdominal pain (78.2%) followed by pain with sexual intercourse (65.2%), rectal pain (52.1%), and urologic pain (36.9%). A total of 43% of patients responded to treatment with neuromodulators. Combined therapies for myofascial pain syndrome, as well as treatment of visceral pain with inferior or superior hypogastric plexus blocks, proved to be very beneficial. S3 pulsed radiofrequency (PRF) plus inferior hypogastric plexus block or botulinum toxin enabled us to prolong response time by more than 3.5 months. Conclusion: Treatment of the unresponsive patient should be interdisciplinary. Depending on the history and exploratory findings, therapy should preferably be combined with neuromodulators, myofascial pain therapies, and S3 PRF plus inferior hypogastric plexus blockade.

Identification and analysis of novel endometriosis biomarkers via integrative bioinformatics

Endometriosis is a gynecological disease prevalent in women of reproductive age, and it is characterized by the ectopic presence and growth of the eutopic endometrium. The pathophysiology and diagnostic biomarkers of endometriosis have not yet been comprehensively determined. To discover molecular markers and pathways underlying the pathogenesis of endometriosis, we identified differentially expressed genes (DEGs) in three Gene Expression Omnibus microarray datasets (GSE11691, GSE23339, and GSE7305) and performed gene set enrichment analysis (GSEA) and protein-protein interaction (PPI) network analyses. We also validated the identified genes via immunohistochemical analysis of tissues obtained from patients with endometriosis or healthy volunteers. A total of 118 DEGs (79 upregulated and 39 downregulated) were detected in each dataset with a lower (fold change) FC cutoff (log2|FC| > 1), and 17 DEGs (11 upregulated and six downregulated) with a higher FC cutoff (log2|FC| > 2). KEGG and GO functional analyses revealed enrichment of signaling pathways associated with inflammation, complement activation, cell adhesion, and extracellular matrix in endometriotic tissues. Upregulation of seven genes (C7, CFH, FZD7, LY96, PDLIM3, PTGIS, and WISP2) out of 17 was validated via comparison with external gene sets, and protein expression of four genes (LY96, PDLIM3, PTGIS, and WISP2) was further analyzed by immunohistochemistry and western blot analysis. Based on these results, we suggest that TLR4/NF-κB and Wnt/frizzled signaling pathways, as well as estrogen receptors, regulate the progression of endometriosis. These pathways may be therapeutic and diagnostic targets for endometriosis.

Gut Microbiota Exceeds Cervical Microbiota for Early Diagnosis of Endometriosis

The diagnosis of endometriosis is typically delayed by years for the unexclusive symptom and the traumatic diagnostic method. Several studies have demonstrated that gut microbiota and cervical mucus potentially can be used as auxiliary diagnostic biomarkers. However, none of the previous studies has compared the robustness of endometriosis classifiers based on microbiota of different body sites or demonstrated the correlation among microbiota of gut, cervical mucus, and peritoneal fluid of endometriosis, searching for alternative diagnostic approaches. Herein, we enrolled 41 women (control, n = 20; endometriosis, n = 21) and collected 122 well-matched samples, derived from feces, cervical mucus, and peritoneal fluid, to explore the nature of microbiome of endometriosis patients. Our results indicated that microbial composition is remarkably distinguished between three body sites, with 19 overlapped taxa. Moreover, endometriosis patients harbor distinct microbial communities versus control group especially in feces and peritoneal fluid, with increased abundance of pathogens in peritoneal fluid and depletion of protective microbes in feces. Particularly, genera of Ruminococcus and Pseudomonas were identified as potential biomarkers in gut and peritoneal fluid, respectively. Furthermore, novel endometriosis classifiers were constructed based on taxa selected by a robust machine learning method. These results demonstrated that gut microbiota exceeds cervical microbiota in diagnosing endometriosis. Collectively, this study reveals important insights into the microbial profiling in different body sites of endometriosis, which warrant future exploration into the role of microbiota in endometriosis and highlighted values on gut microbiota in early diagnosis of endometriosis.

Computational Models for Diagnosing and Treating Endometriosis

Endometriosis is a common but poorly understood disease. Symptoms can begin early in adolescence, with menarche, and can be debilitating. Despite this, people often suffer several years before being correctly diagnosed and adequately treated. Endometriosis involves the inappropriate growth of endometrial-like tissue (including epithelial cells, stromal fibroblasts, vascular cells, and immune cells) outside of the uterus. Computational models can aid in understanding the mechanisms by which immune, hormone, and vascular disruptions manifest in endometriosis and complicate treatment. In this review, we illustrate how three computational modeling approaches (regression, pharmacokinetics/pharmacodynamics, and quantitative systems pharmacology) have been used to improve the diagnosis and treatment of endometriosis. As we explore these approaches and their differing detail of biological mechanisms, we consider how each approach can answer different questions about endometriosis. We summarize the mathematics involved, and we use published examples of each approach to compare how researchers: (1) shape the scope of each model, (2) incorporate experimental and clinical data, and (3) generate clinically useful predictions and insight. Lastly, we discuss the benefits and limitations of each modeling approach and how we can combine these approaches to further understand, diagnose, and treat endometriosis.

A critical appraisal of the circulating levels of differentially expressed microRNA in endometriosis†

Endometriosis is a common gynecological condition characterized by estrogen dependence, chronic pelvic pain, infertility, and diagnostic delay of between 5.4 and 12 years. Despite extensive study, no biomarker, either alone or in combination with other markers, has proven superior to laparoscopy for the diagnosis of endometriosis. Recent studies report that circulating levels of differentially expressed microRNA (miRNA) in women with endometriosis compared with controls are potential diagnostic tools. However, the lack of replication and absence of validated differential expression in novel study populations have led some to question the diagnostic value of miRNA. To elucidate potential reasons for the lack of replication of study results and explore future directions to enhance replicability of circulating miRNA results, we carried out an electronic search of the miRNA literature published between 2000 and 2020. Eighteen studies were identified in which 63 different miRNAs were differentially expressed in the circulation of women with endometriosis compared with controls. However, the differential expressions of only 14 miRNAs were duplicated in one or more studies. While individual miRNAs lacked diagnostic value, miRNA panels yielded sensitivity and specificity equal to or better than laparoscopy in five studies. Important differences in study design, sample processing, and analytical methods were identified rendering direct comparisons across studies problematic and could account for the lack of reproducibility of study results. We conclude that while the results of miRNA studies to date are encouraging, refinements to study design and analytical methods should enhance the reliability of circulating miRNA for the diagnosis of endometriosis.

miRNAs and lncRNAs: Potential Non-Invasive Biomarkers for Endometriosis

Many studies have tried to understand the mechanism of endometriosis and its manner of manifestation. However, the only method of diagnosis considered as the gold standard in endometriosis is an invasive method called exploratory laparoscopy. Hence, there is a need to identify non-invasive or minimally invasive methods to minimize patients' suffering, thus increasing their addressability at the earliest possible staging of the disease, and to diagnose this condition as soon as possible. miRNAs (microRNAs) and lncRNAs (long-noncoding RNAs) are potential non-invasive diagnostic methods for endometriosis. Multiple clinical trials indicate that miRNA can be used as a non-invasive method in the diagnosis and differentiation of endometriosis stages.

Endometriosis: Epidemiology, Classification, Pathogenesis, Treatment and Genetics (Review of Literature)

Endometriosis is a “mysterious” disease and its exact cause has not yet been established. Among the etiological factors, congenital, environmental, epigenetic, autoimmune and allergic factors are listed. It is believed that the primary mechanism of the formation of endometriosis foci is retrograde menstruation, i.e., the passage of menstrual blood through the fallopian tubes into the peritoneal cavity and implantation of exfoliated endometrial cells. However, since this mechanism is also observed in healthy women, other factors must also be involved in the formation of endometriosis foci. Endometriosis is in many women the cause of infertility, chronic pain and the deterioration of the quality of life. It also represents a significant financial burden on health systems. The article presents a review of the literature on endometriosis—a disease affecting women throughout the world.

The role of endometrial stem cells in the pathogenesis of endometriosis and their application to its early diagnosis†

Pelvic pain, infertility, and a high postoperative recurrence rate are associated with endometriosis and adversely affect the physical and mental health of patients. Moreover, these factors place a heavy burden on families and society. The identification of endometrial stem cells (EnSCs) in the eutopic endometrium, menstrual blood, and ectopic lesions of women with endometriosis not only provides new research objects in the context of endometriosis but also promotes and improves our understanding of its pathogenesis. Furthermore, based on previous studies, we reasonably suppose that dysfunctions of eutopic EnSCs play a critical role in the onset of endometriosis and directly cause abnormalities in the endometrium; subsequently, retrograde menstruation facilitates the delivery of abnormal endometrial tissues to the ovaries and pelvic cavity, where they ectopically implant, grow, and form ectopic lesions. Additionally, as a chronically progressive disease, there is a delay (3-11 years) from the first onset of symptoms to the diagnosis of endometriosis. Therefore, the development of a method for early diagnosis with high sensitivity and specificity is essential for endometriosis patients and has the potential to enable early treatment, prevent endometriosis progression, and relieve pain in patients. Thus, focusing on EnSCs will contribute to clarifying the potential pathogenesis of endometriosis and provide support for the application of EnSCs as therapeutic and early diagnostic targets in endometriosis treatment.

SUMMARY SENTENCE

Focusing on endometrial stem cells (EnSCs) will contribute to clarifying the potential pathogenesis of endometriosis and provide support for the application of EnSCs as therapeutic and early diagnostic targets in endometriosis treatment.

Endometrial microbiota is more diverse in people with endometriosis than symptomatic controls

Endometriosis is a chronic, estrogen-dependent gynecological condition affecting approximately 10% of reproductive age women. The most widely accepted theory of its etiology includes retrograde menstruation. Recent reports suggest the uterus is not sterile. Thus, the refluxed menstrual effluent may carry bacteria, and contribute to inflammation, the establishment and growth of endometriotic lesions. Here, we compared and contrasted uterine bacteria (endometrial microbiota) in people with surgically confirmed presence (N = 12) or absence of endometriosis (N = 9) using next-generation 16S rRNA gene sequencing. We obtained an average of > 9000 sequence reads per endometrial biopsy, and found the endometrial microbiota of people with endometriosis was more diverse (greater Shannon Diversity Index and proportion of 'Other' taxa) than symptomatic controls (with pelvic pain, surgically confirmed absence of endometriosis; diagnosed with other benign gynecological conditions). The relative abundance of bacterial taxa enriched in the endometrial microbiota of people with endometriosis belonged to the Actinobacteria phylum (Gram-positive), Oxalobacteraceae (Gram-negative) and Streptococcaceae (Gram-positive) families, and Tepidimonas (Gram-negative) genus, while those enriched in the symptomatic controls belonged to the Burkholderiaceae (Gram-negative) family, and Ralstonia (Gram-negative) genus. Taken together, results suggest the endometrial microbiota is perturbed in people with endometriosis.

Circular RNA PIP5K1A (circPIP5K1A) accelerates endometriosis progression by regulating the miR-153-3p/Thymosin Beta-4 X-Linked (TMSB4X) pathway

As a common gynecologic disease, endometriosis (EM) poses a threat to the reproductive health of about 10% women globally. Recent studies have revealed that circular RNAs (circRNAs) are deeply implicated in EM pathogenesis. However, the functions of circPIP5K1A in EM have not been studied yet. Our study intended to uncover the molecular mechanism of circPIP5K1A in EM. In this work, gene and protein expressions were determined by RT-qPCR or Western blotting. CCK-8, wound healing, transwell, and flow cytometry assays were conducted to analyze cell viability, migration, invasion, cell cycle, and apoptosis. Additionally, bioinformatics analysis, dual-luciferase reporter assay, as well as RIP assay were performed to investigate the combination between miR-153-3p and circPIP5K1A or TMSB4X. Herein, we found remarkable high circPIP5K1A expression in EM tissues and cells. Silencing of circPIP5K1A suppressed proliferation, restrained cell cycle, increased cell apoptosis, and decreased migration and invasion in EM cells. In addition, miR-153-3p inhibition could abrogate the impacts of circPIP5K1A knockdown on EM progression in vitro. Also, we found that circPIP5K1A regulated TMSB4X level via interaction with miR-153-3p in EM cells. Besides, circPIP5K1A promoted EM progression via TMSB4X. Moreover, TMSB4X could activate the TGF-β signaling in hEM15A cells. To sum up, our study elucidated that circPIP5K1A accelerated EM progression in vitro by activating the TGF-β signaling pathway via the miR-153-3p/TMSB4X axis, providing a potential clinical target for EM treatment.

Circular RNA circZFPM2 promotes epithelial-mesenchymal transition in endometriosis by regulating miR-205-5p/ZEB1 signalling pathway

Endometriosis is a debilitating gynecological disease affecting millions of women worldwide, but its exact pathogenesis remains unclear. Circular RNAs (circRNAs) have been demonstrated to be important regulators in multiple diseases. Nonetheless, the potential regulatory mechanism of aberrant circRNA expression in endometriosis has been elusive. The up-regulated circZFPM2 in ectopic endometrial tissues was previously screened by circRNA high-throughput sequencing and was furtherly validated by quantitative real time reverse transcriptase polymerase chain reaction (RT-qPCR). Overexpression of circZFPM2 promoted the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in Ishikawa and End1/E6E7 cells, whereas silencing circZFPM2 produced the opposite effect. Luciferase reporter assays validated that circZFPM2 could directly target miR-205-5p and miR-205-5p target ZEB1. RT-qPCR results showed that miR-205-5p was underexpressed while ZEB1 was overexpressed in ectopic endometrial tissues compared with their expression in eutopic endometria and non-endometriosis control endometria. The expression level of miR-205-5p was inversely proportional and that of ZEB1 was directly proportional with the proliferative, migrative, and invasive ability of endometrial cells. Further in vitro investigation indicated that miR-205-5p could inhibit EMT by targeting ZEB1. Subsequent rescue experiments confirmed that circZFPM2 could induce EMT and promote cell proliferation, migration, and invasion cascades through the miR-205-5p /ZEB1 signaling pathway. Conclusively, circZFPM2 may present a promising biomarker in the diagnosis and treatment of endometriosis.

Endometriosis and Uterine Fibroids and Their Associations with Elevated C-Reactive Protein and Leukocyte Telomere Length Among a Representative Sample of U.S. Women: Data from the National Health and Nutrition Examination Survey, 1999-2002

Background: Recent studies have suggested a link between reproductive health and later-life chronic conditions, yet the mechanism remains unclear. One proposed mechanism is through chronic inflammation. The objective of this study was to examine the association between endometriosis and uterine fibroids and biomarkers of inflammation and cellular aging. Materials and Methods: We used data from the National Health and Nutrition Examination Survey (N = 2342; 1999-2002). Adjusted logistic and linear regression were used to examine the association between these two reproductive conditions and elevated C-reactive protein (CRP; >3.0 mg/L) and leukocyte telomere length (T/S ratio), respectively. Given that a greater length of time spent with a condition may represent persistence of an inflammatory process, we further examined the association between time since disease diagnosis on telomere length among the subset of women with diagnosed endometriosis and fibroids. Results: Women with endometriosis had greater odds of having elevated CRP than those without endometriosis (OR = 1.60; 95% CI: 1.05 to 2.45). Women with endometriosis had a shorter telomere length than women without endometriosis (-3.4, 95% CI: -7.3 to -0.3 in age-adjusted models and -2.9, 95% CI: -8.8 to 3.5 in fully adjusted models). Telomeres were 1% (95% CI: -1.2 to -0.6) shorter for every elapsed year since endometriosis diagnosis. No substantive patterns emerged between uterine fibroids and CRP or telomere length. Conclusions: Women with endometriosis (or a longer duration of time spent with endometriosis) had higher inflammatory markers and shorter mean telomere length. These results provide further insights into potential mechanisms linking endometriosis to chronic disease and later-life health.

Assessment of Nerve Fiber Density and Expression of Hormonal Receptors Within Rectosigmoid Endometriosis Nodules

STUDY OBJECTIVE

To assess nerve fiber density and expression of hormone receptors in bowel endometriosis.

DESIGN

Cross-sectional study.

SETTING

Private hospital.

PATIENTS

Women with endometriosis undergoing laparoscopic segmental bowel resection (n = 54).

INTERVENTIONS

Tissue samples were obtained from patients with surgically treated rectosigmoid endometriosis.

MEASUREMENTS AND MAIN RESULTS

The rectosigmoid specimen containing the endometriosis nodule was manually sectioned and divided into 3 areas: core of the nodule, margin of the nodule, and healthy bowel tissue. The intensity of expression of estrogen and progesterone receptors was evaluated by immunohistochemistry and measured according to the Allred score. Nerve fibers were stained by immunohistochemistry using Protein Gene Product 9.5, and the density of nerve fillets was counted and expressed in number/mm². All glandular and stromal cells stained for estrogen; however, glandular cells stained more strongly than stromal cells (61.1% vs 35.2%; p = .01). Most of glandular and stromal cells stained strongly for progesterone receptors (90.7% vs 98.1%; p = .2). The density of nerve fibers was very high in the margin of the nodule (172.22±45.66/mm²), moderate in healthy bowel tissue (111.48±48.57/mm²), and very low in the core of the nodule (7.31±4.9/mm²); p = .01.

CONCLUSION

Both glandular and stromal cells within the rectosigmoid endometriosis nodule express estrogen and progesterone receptors. Higher intensity of expression of estrogen receptors occurs in glandular cells. The density of nerve fibers is extremely high at the nodule margin and very low in the center of the nodule.

Effect of psychosocial trauma and stress on sexual dysfunction in women with endometriosis

BACKGROUND

Endometrial tissue plays an important role in the regulation of female fertility and there is evidence that endometrial pathology (including endometriosis) is closely related to endocrine disorders. On the other hand, various neuroendocrine changes can be significantly affected by psychosocial stress. In connection with these findings, we tested the relationship between neuroendocrine changes, sexual dysfunction, psychosocial/traumatic stress, and dissociative symptoms in women with endometriosis.

METHODS

A total of 65 patients with endometriosis were included in the study. Clinical examinations were focused on the biochemical analysis of neuroendocrine markers of endometriosis (cancer antigen 125 [CA 125] and cancer antigen 19-9 [CA 19-9]), estradiol, psychometric evaluation of sexual dysfunction, psychosocial/traumatic stress, and dissociative symptoms.

RESULTS

The results showed significant Spearman correlations between the values of the revised range of sexual difficulties for sexual dysfunction (Revised Female Sexual Distress Scale), psychosocial/traumatic stress (Trauma Symptoms Checklist) (R = 0.31), and dissociative symptoms (Somatoform Dissociation Questionnaire) (R = 0.33). Positive correlations were also found between CA 125 and CA 19-9 (R = 0.63), and between CA 125 and the results of the values of the revised scale of sexual difficulties for sexual dysfunction (Revised Female Sexual Distress Scale) (R = 0.29). Also psychosocial/traumatic stress (Trauma Symptoms Checklist) significantly correlated with CA 125 (R = 0.38) and with CA 19-9 (R = 0.33).

CONCLUSION

These results represent the first findings regarding the relationship of the neuroendocrine markers CA 125 and CA 19-9 and sexual dysfunction with trauma/stress-related symptoms and dissociative symptoms in women with endometriosis.

Exploring the Potential Key IncRNAs with Endometriosis by Construction of a ceRNA Network

Purpose

The etiology and pathophysiology of endometriosis remain unclear. Current research indicates long noncoding RNA (lncRNA) may play an important role in the pathogenesis and development of endometriosis. However, the molecular mechanism of lncRNA in endometriosis is far from clear.

Patients and Methods

The lncRNA and mRNA expression of 8 patients with ovarian endometriosis were determined by high-throughput RNA sequencing (8 ectopic endometria samples vs 8 eutopic endometria samples), and miRNA expression profiles were obtained from our previous study. Then a lncRNA-associated competing endogenous RNA (ceRNA) network was constructed by combining the regulatory interaction and negative co-expression interaction between the differentially expressed lncRNAs/mRNAs and miRNAs by different rules.

Results

The constructed lncRNA-related ceRNA network was composed of two separate networks, network 1 including 14,137 dysregulated lncRNA–mRNA interactions, referring to 242 lncRNAs, 55 miRNAs and 1600 mRNAs, network 2 including 4459 dysregulated lncRNA–mRNA interactions, referring to 111 lncRNAs, 39 miRNAs and 1151 mRNAs. The top six hub lncRNAs (LINC01140, MSC-AS1, HAGLR, CKMT2-AS1, JAKMIP2-AS1, AL365361.1) in the significant ternary relationship of mRNA–miRNA–lncRNA in network 1, and the top six hub lncRNAs (PAX8-AS1, MIR17HC, PART1, HOXA-AS3, PLAC4, LINC00511) in the significant ternary relationship of mRNA–miRNA–lncRNA in network 2 were selected. Functional enrichment analysis of these lncRNA-related mRNAs indicated that the lncRNAs in network 1 mainly take part in positive regulation of phagocytosis, myeloid leukocyte activation, and tissue remodeling, while the lncRNAs in network 2 mainly take part in negative regulation of cell proliferation, blood vessel development and regulation of epithelial cell differentiation, which is consistent with the results obtained from the different rules to construct the networks.

Conclusion

lncRNA-related ceRNA network analysis recognized key lncRNAs related to the development of endometriosis.

The Potential of Non-Invasive Biomarkers for Early Diagnosis of Asymptomatic Patients with Endometriosis

Endometriosis is a disease that affects women of reproductive age and has a significantly negative impact on their well-being. The main symptoms are dysmenorrhoea, chronic pelvic pain and infertility. In many patients the diagnostic process is very long and can take up to 8-12 years. Laparoscopy, an invasive method, is still necessary to confirm the diagnosis. Therefore, development of more effective diagnostic markers appears to be of the utmost importance for early diagnosis of endometriosis and provision of appropriate treatment. From a clinical point of view, detection of early-stage endometriosis in asymptomatic patients is an ideal situation since early diagnosis of endometriosis may delay the onset of symptoms as well as prevent progression and complications. In the meantime, Cancer Antigen 125 (CA-125) is still the most frequently studied and used marker. Other glycoproteins, growth factors and immune markers seem to play an important role. However, the search for an ideal endometriosis marker is still underway. Further studies into the pathogenesis of endometriosis will help to identify biomarkers or sets of biomarkers with the potential to improve and speed up the diagnostic process in a non-invasive way.

Current biomarkers for the detection of endometriosis

A clinically reliable non-invasive test for endometriosis is expected to reduce the diagnostic delay. Although varieties of biomarkers have been investigated for decades, and cancer antigen-125, cancer antigen-199, interleukin-6, and urocortin were the most studied ones among hundreds of biomarkers, no clinically reliable biomarkers have been confirmed so far. Some emerging technologies including “omics” technologies, molecular imaging techniques, and microRNAs are promising in solving these challenges, but their utility to detect endometriosis has yet to be verified. New combinations of researched indicators or other non-invasive methods and further exploration of the emerging technologies may be new targets and future research hotspots for non-invasive diagnosis of endometriosis. In conclusion, researches of biomarkers for the detection of endometriosis are still ongoing and may benefit from novel molecular biology, bioinformatics methods and a combination of more diverse monitoring methods. Though it will be a daunting task, the identification of a specific set of diagnostic biomarkers will undoubtedly improve the status of endometriosis.

Analysis of differences in the transcriptomic profiles of eutopic and ectopic endometriums in women with ovarian endometriosis

Background

Endometriosis is a common gynecological disease among women in their reproductive years. Although much effort has been made, the pathogenesis of this disease and the detailed differences between eutopic endometrial cells and ectopic endometrial cells are still unclear.

Methods

In this study, eutopic and ectopic endometrial cells were collected from patients with and without endometriosis and RNA sequencing was performed. The gene expression patterns and differentially expressed genes (DEGs) in eutopic and ectopic endometrial cells, as well as control endometrial cells, were analyzed using a weighted gene co-expression network analysis (WGCNA) and the DESeq2 package. The functions of significant genes were detected using Gene ontology (GO) enrichment analysis, and qRT-PCR validation was performed.

Results

The results indicated that eight gene modules were found among these three groups. They also indicated that the gene module, which is highly related to eutopic endometrial cells, was mainly enriched in cell adhesion, embryo implantation, etc., while the gene module related to ectopic endometrial cells was mainly enriched in cell migration, etc. The results of differential expression analysis were generally consistent with the WGCNA results through identified significant DEGs between different groups. These DEGs may play an important role in the occurrence of endometriosis, including the infertility associated gene ARNTL and PIWIL2, tissue remodeling gene MMP11, cell survival and migration gene FLT1, inflammatory response gene GNLY, the tumor suppressor genes PLCD1, etc. Further analysis suggested the function of adhesion is stronger in ectopic endometrial cells than in eutopic endometrial cells, while the ectopic endometrium may have a higher potential risk of malignant transformation than eutopic endometrium.

Conclusions

Overall, these data provide a reference for understanding the pathogenesis of endometriosis and its relationship with malignant transformation.

A short anogenital distance on MRI is a marker of endometriosis

STUDY QUESTION

Could the anogenital distance (AGD) as assessed by MRI (MRI-AGD) be a diagnostic tool for endometriosis?

SUMMARY ANSWER

A short MRI-AGD is a strong diagnostic marker of endometriosis.

WHAT IS KNOWN ALREADY

A short clinically assessed AGD (C-AGD) is associated with the presence of endometriosis.

STUDY DESIGN SIZE DURATION

This study is a re-analysis of previously published data from a case-control study.

PARTICIPANTS/MATERIALS SETTING METHODS

Women undergoing pelvic surgery from January 2018 to June 2019 and who had a preoperative pelvic MRI were included. C-AGD was measured at the beginning of the surgery by a different operator who was unaware of the endometriosis status. MRI-AGD was measured retrospectively by a senior radiologist who was blinded to the final diagnosis. Two measurements were made: from the posterior wall of the clitoris to the anterior edge of the anal canal (MRI-AGD-AC), and from the posterior wall of the vagina to the anterior edge of the anal canal (MRI-AGD-AF).

MAIN RESULTS AND THE ROLE OF CHANCE

The study compared MRI-AGD of 67 women with endometriosis to 31 without endometriosis (controls). Average MRI-AGD-AF measurements were 13.3 mm (±3.9) and 21.2 mm (±5.4) in the endometriosis and non-endometriosis groups, respectively (P < 10-5). Average MRI-AGD-AC measurements were 40.4 mm (±7.3) and 51.1 mm (±8.6) for the endometriosis and non-endometriosis groups, respectively (P < 10-5). There was no difference of MRI-AGD in women with and without endometrioma (P = 0.21), or digestive involvement (P = 0.26). Moreover, MRI-AGD values were independent of the revised score of the American Society of Reproductive Medicine and the Enzian score. The diagnosis of endometriosis was negatively associated with both the MRI-AGD-AF (β = -7.79, 95% CI (-9.88; -5.71), P < 0.001) and MRI-AGD-AC (β = -9.51 mm, 95% CI (-12.7; 6.24), P < 0.001) in multivariable analysis. Age (β = +0.31 mm, 95% CI (0.09; 0.53), P = 0.006) and BMI (β = +0.44 mm, 95% CI (0.17; 0.72), P = 0.001) were positively associated with the MRI-AGD-AC measurements in multivariable analysis. MRI-AGD-AF had an AUC of 0.869 (95% CI (0.79; 0.95)) and outperformed C-AGD. Using an optimal cut-off of 20 mm for MRI-AGD-AF, a sensitivity of 97.01% and a specificity of 70.97% were noted.

LIMITATIONS REASONS FOR CAUTION

This was a retrospective analysis and no adolescents had been included.

WIDER IMPLICATIONS OF THE FINDINGS

This study is consistent with previous works associating a short C-AGD with endometriosis and the absence of correlation with the disease phenotype. MRI-AGD is more accurate than C-AGD in this setting and could be evaluated in the MRI examination of patients with suspected endometriosis.

STUDY FUNDING/COMPETING INTERESTS

N/A.

TRIAL REGISTRATION NUMBER

The protocol was approved by the 'Groupe Nantais d'Ethique dans le Domaine de la Santé' and registered under reference 02651077.

Nanomedicines for Endometriosis: Lessons Learned from Cancer Research

Endometriosis is an incurable gynecological disease characterized by the abnormal growth of endometrium-like tissue, characteristic of the uterine lining, outside of the uterine cavity. Millions of people with endometriosis suffer from pelvic pain and infertility. This review aims to discuss whether nanomedicines that are promising therapeutic approaches for various diseases have the potential to create a paradigm shift in endometriosis management. For the first time, the available reports and achievements in the field of endometriosis nanomedicine are critically evaluated, and a summary of how nanoparticle-based systems can improve endometriosis treatment and diagnosis is provided. Parallels between cancer and endometriosis are also drawn to understand whether some fundamental principles of the well-established cancer nanomedicine field can be adopted for the development of novel nanoparticle-based strategies for endometriosis. This review provides the state of the art of endometriosis nanomedicine and perspective for researchers aiming to realize and exploit the full potential of nanoparticles for treatment and imaging of the disorder.

Ovarian endometriosis, a precursor of ovarian cancer: Histological aspects, gene expression and microRNA alterations (Review)

Ovarian endometriosis is a frequent chronic gynecological disease with an uncertain evolution regarding its progression or association with ovarian malignant lesions. The present review summarized the histological aspects, gene expression and microRNA (miRNA/miR) alterations associated with ovarian endometriosis and cancer and their possible interaction. The endometriosis-ovarian cancer interaction has been proposed by certain researchers as a single entity. Histological results indicated that endometriosis has been in different circumstances coexisting with ovarian cancer, with reference to endometrioid and clear cell carcinoma. Endometriosis with moderate and severe atypia can influence cell proliferation and architecture, resulting in a possible malignant transformation. Gene expression analysis indicated that the pathologies of both endometriosis and ovarian cancer are characterized by genetic instability from a molecular point of view, as several important genetic mutations, including ARID1A, PI3KCA, PTEN, BRCA1, BRCA2, TP53 and KRAS genes, were identified. miRNA alterations have been implicated in the regulation of gene expression. Common dysregulated miRNAs, such as miR-331, miR-335, miR-891, miR-548, miR-124, miR-148, miR-215, miR-192, miR-337, miR-153, miR-155, miR-144, miR-221 and miR-3688 were extensively investigated in understanding endometriosis and ovarian cancer evolution. From a combined viewpoint including histological aspects, gene expression and miRNA alterations, it is reasonable to speculate that endometriosis is associated with ovarian cancer. Ovarian endometriosis lesions may present a risk for ovarian malignant lesions, which supports a model of endometriosis as a malignant precursor. However, the endometriosis-ovarian cancer association is not widely accepted in the literature and additional studies are required to validate this association.

Endometriosis Is Associated with a Significant Increase in hTERC and Altered Telomere/Telomerase Associated Genes in the Eutopic Endometrium, an Ex-Vivo and In Silico Study

Telomeres protect chromosomal ends and they are maintained by the specialised enzyme, telomerase. Endometriosis is a common gynaecological disease and high telomerase activity and higher hTERT levels associated with longer endometrial telomere lengths are characteristics of eutopic secretory endometrial aberrations of women with endometriosis. Our ex-vivo study examined the levels of hTERC and DKC1 RNA and dyskerin protein levels in the endometrium from healthy women and those with endometriosis (n = 117). The in silico study examined endometriosis-specific telomere- and telomerase-associated gene (TTAG) transcriptional aberrations of secretory phase eutopic endometrium utilising publicly available microarray datasets. Eutopic secretory endometrial hTERC levels were significantly increased in women with endometriosis compared to healthy endometrium, yet dyskerin mRNA and protein levels were unperturbed. Our in silico study identified 10 TTAGs (CDKN2A, PML, ZNHIT2, UBE3A, MCCC2, HSPC159, FGFR2, PIK3C2A, RALGAPA1, and HNRNPA2B1) to be altered in mid-secretory endometrium of women with endometriosis. High levels of hTERC and the identified other TTAGs might be part of the established alteration in the eutopic endometrial telomerase biology in women with endometriosis in the secretory phase of the endometrium and our data informs future research to unravel the fundamental involvement of telomerase in the pathogenesis of endometriosis.