Pathogenesis of endometriosis: The role of initial infection and subsequent sterile inflammation (Review)

Correlation between dysbiosis of vaginal microecology and endometriosis: A systematic review and meta-analysis

BACKGROUND

Endometriosis, a complex gynecological condition, involves inflammation and immune dysregulation. The vaginal microbiota, characterized by its diversity, is an integral part of the vaginal microecology-interacting with vaginal anatomy, the endocrine system, and local mucosal immunity. Imbalances in this microecology are known to precipitate various inflammatory diseases. Despite extensive research, the connection between vaginal microbiota dysbiosis and endometriosis remains a subject of debate. Our study assesses the association between vaginal microecology dysbiosis and endometriosis.

METHODS

We systematically searched major electronic databases in English, including Embase, PubMed, The Cochrane Library, MEDLINE (Ovid), BIOSIS (Ovid), China National Knowledge Infrastructure (CNKI), and Wanfang, up to August 15, 2023. Selected articles underwent screening based on predefined inclusion and exclusion criteria. Normal vaginal microecology was defined as a negative Amsel/Spiegel test or Nugent score of 0-3, or Lactobacillus predominance determined by 16S rRNA gene amplification sequencing. Deviations from this norm were classified as dysbiosis, further categorized into bacterial vaginosis (BV) and intermediate BV. Data analysis utilized Revman 5.4, with effect sizes presented as Odds Ratios (OR) and 95% Confidence Intervals (CI).

RESULTS

Out of 1081 articles, eight met the inclusion criteria. Utilizing fixed-effect models due to low heterogeneity, the analysis revealed a positive association between dysbiosis and endometriosis (OR = 1.17, 95% CI 0.81-1.70; I2 = 0%), but showed a slight negative association between normal vaginal microecology with endometriosis (OR = 0.90, 95% CI 0.55-1.46; I2 = 29%). However, the association was not significant. Subgroup and sensitivity analyses corroborated the stability of these associations.

CONCLUSION

A positive correlation exists between vaginal microecology dysbiosis and endometriosis, notably with intermediate BV. However, the mechanisms underpinning this relationship remain elusive, highlighting the need for further research to overcome limitations.

TRIAL REGISTRATION

Registration number: CRD42023445163.

A Study on the Analysis of Important Gene Networks and Pathways Involved in Progression of Endometriosis to Ovarian Endometrioma Cyst

Endometriosis (EM) is a gynecological condition known by the manifestation of endometrium alike soft tissue external to the usual place affecting up to 10% of all womenfolk in the reproductively active stage. However, the pathological process of endometriosis is not identified fully. The study aims to investigate the genes associated with the progression of endometriosis and its pathways using bioinformatics tools and techniques. The gene expression profile of three sets was retrieved, and bioinformatics data analysis was carried out for the microarray samples using GEO, DAVID, and STICH. Differently expressed genes (DEGs) refer to genes that exhibit significant changes in their expression levels between different conditions or groups, such as between different cell types, treatments, disease states, or developmental stages. DEG was determined based on a significant cutoff resulting in 298 unique elements based on the GEO Venn diagram map. DAVID (database for annotation, visualization, and integrated discovery) helps understand the biological significance of the data by identifying overrepresented biological terms, pathways, and functional annotations among a set of genes or proteins of interest. DAVID analysis revealed positively and negatively associated genes and followed by target proteins. DAVID is helpful for getting results of molecular mechanisms and pathways associated with DEGs. The gene expression studies showed that the m-RNA expression of all the genes was upregulated in the PA1 cell line. The present study identified five genes (COMT, CYP19A1, GALT, LTA, and STAR) from 298 unique DEGs using microarray data analysis, and 5 protein targets were also identified that were linked with EM. The study concludes that this information may provide a bridging gap in understanding the progression of endometriosis.

Association Between Pelvic Inflammatory Disease and Risk of Endometriosis: A Systematic Review and Meta-Analysis

Background: Endometriosis is a common chronic disorder, which leads to dysmenorrhea, dyspareunia, pelvic chronic pain, and infertility. It affects ∼6% to 10% of the general female population. However, the etiology of endometriosis remained unclear. We aimed to systematically assess the association between pelvic inflammatory disease (PID) and the risk of endometriosis. Materials and Methods: Eligible studies published until May 21, 2022, were retrieved from the PubMed, EMBASE, and Web of Science databases. The studies were included based on the following criteria: (1) original articles on the association between PID and risk of endometriosis; (2) randomized controlled trials and cross-sectional, case-control, and cohort studies; and (3) studies involving humans. The Newcastle-Ottawa Quality Assessment Scale was used to assess the quality of the studies included in this systematic review. The association between PID and risk of endometriosis was evaluated using the overall odds ratio (OR) and correlative 95% confidence interval (CI). Results: The meta-analysis included 14 studies with 747,733 patients. The mean prevalence of PID in women with endometriosis was 33.80%. Our quantitative synthesis revealed that endometritis was associated with a significantly increased risk of endometriosis (OR: 1.63, 95% CI: 1.53-1.74, I2 = 59%). Conclusion: We study a statistically significant association between PID and the risk of endometriosis. In particular, endometritis might play an important role in endometriosis, based on the lower heterogeneity of the subgroup analysis. This finding suggests that reducing the incidence of endometritis might aid in the prevention and treatment of endometriosis.

Downregulation of pattern recognition receptors on macrophages involved in aggravation of endometriosis

PROBLEM

In women of reproductive age, endometriosis may contribute to dysmenorrhea, chronic pelvic pain, dyspareunia, infertility, adenomyosis, and endometrial ovarian cyst (EOC). Recent studies have shown that chronic inflammation occurs in the pelvis of endometriosis patients and that this inflammation is exacerbated by immunosuppression, leading to survival endometrial debris. However, the detailed immunological mechanisms underlying the aggravation of inflammation and immunosuppression in endometriosis patients remain unclear.

METHOD OF STUDY

We investigate the alarmins (high-mobility group box-1, IL-33, IL-1α, and S100B protein), proinflammatory cytokines (IL-6 and IL-1β), and immune cells (CD8+ T cells, CD4+ T cells, natural killer cells, natural killer T cells, dendritic cells, and macrophages) in peritoneal fluid of patients with EOC using enzyme-linked immunosorbent assay, electrochemiluminescence, and flow cytometry. Then, we analyzed the correlation between these factors and the aggravating indicators of endometriosis, tumor size and revised American Society for Reproductive Medicine (r-ASRM) score.

RESULTS

Unexpectedly, there was no correlation between each alarmin level and aggravating indicators. However, the expression of pattern recognition receptors, toll-like receptor 4, and receptor of advanced glycation end-products on macrophages was inversely correlated with aggravating indicators.

CONCLUSIONS

The aggravation of endometriosis is associated with a decrease in alarmin receptors but not alarmin levels. Investigation of innate immune systems, such as alarmins and their receptors, may help elucidate new mechanisms of endometriosis.

Genomic characterisation of the overlap of endometriosis with 76 comorbidities identifies pleiotropic and causal mechanisms underlying disease risk

Comorbid conditions can be driven by underlying pleiotropic and causal mechanisms that can provide insights into shared molecular and biological processes contributing to disease risk. Endometriosis is a chronic condition affecting one in nine women of reproductive age and poses many challenges including lengthy diagnostic delays and limited treatment efficacy owing to poor understanding of disease aetiology. To shed light on the underlying biological mechanisms and to identify potential risk factors, we examine the epidemiological and genomic relationship between endometriosis and its comorbidities. In the UK Biobank 292 ICD10 codes were epidemiologically correlated with endometriosis diagnosis, including gynaecological, immune, infection, pain, psychiatric, cancer, gastrointestinal, urinary, bone and cardiovascular traits. A subset of the identified comorbidities (n = 76) underwent follow-up genetic analysis. Whilst Mendelian randomisation suggested causality was not responsible for most comorbid relationships, 22 traits were genetically correlated with endometriosis, including pain, gynaecological and gastrointestinal traits, suggestive of a shared genetic background. Pleiotropic genetic variants and genes were identified using gene-based and colocalisation analysis. Shared genetic risk factors and potential target genes suggest a diverse collection of biological systems are involved in these comorbid relationships including coagulation factors, development of the female reproductive tract and cell proliferation. These findings highlight the diversity of traits with epidemiological and genomic overlap with endometriosis and implicate a key role for pleiotropy in the comorbid relationships.

Gut and reproductive tract microbiota: Insights into the pathogenesis of endometriosis (Review)

Endometriosis is characterized by the presence of endometrial-like tissue outside the uterus and is associated with an inflammatory immune response. The gut and reproductive tract microbiota constitute a protective barrier against infection by pathogens and regulate inflammatory and immune functions. This review summarizes microbiota imbalance (i.e., dysbiosis) in endometriosis and discusses how dysbiosis influences disease development. The literature was searched for studies published from inception to March 2022 in the PubMed and Google Scholar databases using a combination of specific terms. An altered gut and reproductive tract microbiome has been reported in numerous conditions, such as inflammatory bowel disease, allergies, autoimmunity, cancer and reproductive disorders (e.g., endometriosis). Furthermore, microbial dysbiosis is a hallmark of endometriosis and is characterized by a decrease in beneficial probiotics and an increase in pathogenic microbes, which leads to a series of estrobolomic and metabolomic changes. Gut or reproductive tract microbiome dysbiosis was reported in mice, nonhuman primates, and females with endometriosis. Animal models of endometriosis demonstrated the effects of the gut microbiome on lesion growth and vice versa. The immune system mediated by the microbiota-gut-reproductive tract axis triggers an inflammatory response that damages reproductive tract tissue, which possibly leads to endometriosis. However, whether the alteration of eubiosis (a balanced microbiota) to dysbiosis is a cause or a result of endometriosis is unclear. In conclusion, this review provides an overview of the relationship between the gut and reproductive tract microbiome and endometriosis, focusing on the mechanisms by which dysbiosis may increase the risk of disease.

Evaluation of expression of biomarkers of PLAGL1 (ZAC1), microRNA, and their non-coding RNAs in patients with endometriosis

Since the PLAGL1 (ZAC1) gene is expressed in the human endometrium. It may be involved in the etiology of endometrial disorders by its abnormal regulation and expression. This study aimed to investigate the Zac1 gene and related microRNA and LncRNA and its alterations in patients with endometriosis. Blood plasma, ectopic (EC) and eutopic (EU) endometrial samples were gathered from 30 patients with endometriosis and 30 healthy fertile women, and the Q-PCR technique was used to determine the expression level of Zac1 mRNA and microRNAs (miR-1271-5p, hsa-miR-490-3pin) and LncRNAs (TONSL-AS1 TONSL, KCNQ1OT1 KCNQ1). According to the results, the Zac1 gene and KCNQ1OT1 KCNQ1, TONSL-AS1 TONSL LncRNA expression were significantly decreased in the endometriosis group versus the control group (P < 0.05). MiR-1271-5p and hsa-miR-490-3pin microRNA expression were significantly raised in the endometriosis group as opposed to the control group (P < 0.05). In summary, this research for the first time revealed that identifying Zac1 expression provides us with new indicators for evaluating endometriosis.

Pattern-recognition receptors in endometriosis: A narrative review

Endometriosis is closely associated with ectopic focal inflammation and immunosuppressive microenvironment. Multiple types of pattern recognition receptors (PRRs) are present in the innate immune system, which are able to detect pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) in both intracellular and external environments. However, the exact role of PRRs in endometriosis and the underlying molecular mechanism are unclear. PRRs are necessary for the innate immune system to identify and destroy invasive foreign infectious agents. Mammals mainly have two types of microbial recognition systems. The first one consists of the membrane-bound receptors, such as toll-like receptors (TLRs), which recognize extracellular microorganisms and activate intracellular signals to stimulate immune responses. The second one consists of the intracellular PRRs, including nod-like receptors (NLRs) and antiviral proteins retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA-5) with helix enzyme domain. In this review, we mainly focus on the key role of PRRs in the pathological processes associated with endometriosis. PRRs recognize PAMPs and can distinguish pathogenic microorganisms from self, triggering receptor ligand reaction followed by the stimulation of host immune response. Activated immune response promotes the transmission of microbial infection signals to the cells. As endometriosis is characterized by dysregulated inflammation and immune response, PRRs may potentially be involved in the activation of endometriosis-associated inflammation and immune disorders. Toll-like receptor 2 (TLR2), toll-like receptor 3 (TLR3), toll-like receptor 4 (TLR4), nod-like receptor family caspase activation and recruitment domain (CARD) domain containing 5 (NLRC5), nod-like receptor family pyrin domain containing 3 (NLRP3), and c-type lectin receptors (CLRs) play essential roles in endometriosis development by regulating immune and inflammatory responses. Absent in melanoma 2 (AIM2)-like receptors (ALRs) and retinoic acid-inducible gene I-like receptors (RLRs) may be involved in the activation of endometriosis-associated immune and inflammation disorders. PRRs, especially TLRs, may serve as potential therapeutic targets for alleviating pain in endometriosis patients. PRRs and their ligands interact with the innate immune system to enhance inflammation in the stromal cells during endometriosis. Thus, targeting PRRs and their new synthetic ligands may provide new therapeutic options for treating endometriosis.

Correlation of High-Risk Human Papilloma Virus with Deep Endometriosis: A Cross-Sectional Study

Background

Recently, it has been suggested that microbial infections play a role in the pathogenesis of endometriosis. One of the most commonly suggested infections associated with the pathogenesis of endometriosis is human papillomavirus (HPV) infection. The present study is aimed at evaluating the prevalence, types, and risk factors for HPV infection in women with endometriosis and at investigating the association of upper and lower genital tract involvement with HPV and the severity of endometriosis.

Methods

This cross-sectional study was conducted on 81 patients with endometriosis, referred to Rasool Akram Medical Complex in Tehran, Iran, for laparoscopic surgery. The patients' demographic, clinical, and anthropometric data were extracted from their medical records, as well as interviews. The stage of disease was scored based on the revised American Society for Reproductive Medicine (rASRM) classification. The HPV-positive and HPV-negative cases were compared using the chi-square test for categorical variables and Student t-test for continuous variables.

Results

Twenty (24.69%) out of 81 women with endometriosis were infected with HPV (nine cases of pelvic HPV, nine cases of vaginal HPV, and two cases of both pelvic and vaginal HPV). The HPV-infected women had a significantly lower infertility rate (15% vs. 45.9%; P = 0.014). The VAS scores for dysmenorrhea and dyspareunia were relatively the same in the two groups (P > 0.05). HPV 6 and HPV 11 were the most common types of HPV, reported in 35% and 30% of endometriosis cases, respectively.

Conclusion

The prevalence of HPV was 24.69%, and low-risk genotypes were dominant. No significant association was found between HPV and the severity of endometriosis.

Analysis of characteristic genes and ceRNA regulation mechanism of endometriosis based on full transcriptional sequencing

Background: Endometriosis is a common gynecological disorder that usually causes infertility, pelvic pain, and ovarian masses. This study aimed to mine the characteristic genes of endometriosis, and explore the regulatory mechanism and potential therapeutic drugs based on whole transcriptome sequencing data and resources from public databases, providing a theoretical basis for the diagnosis and treatment of endometriosis.

Methods: The transcriptome data of the five eutopic (EU) and ectopic (EC) endometrium samples were obtained from Beijing Obstetrics and Gynecology Hospital, Beijing, China, and dinified as the own data set. The expression and clinical data of EC and EU samples in GSE25628 and GSE7305 datasets were obtained from the GEO database (https://www.ncbi.nlm.nih.gov/gds). Differential gene expression analysis and weighted gene co-expression network analysis (WGCNA) were used to identify the endometriosis-related differentially expressed genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted by the “clusterProfiler” R package. Then, characteristic genes for endometriosis were identified by the least absolute shrinkage and selection operator (LASSO) and support vector machine recursive feature elimination (SVM-RFE) algorithm. The expression of characteristic genes was verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western-blot. The receiver operating characteristic (ROC) curve was used to evaluate the discriminatory ability of characteristic genes. We assessed the abundance of infiltrating immune cells in each sample using MCP-counter and ImmuCellAI algorithms. The competitive endogenous RNA (ceRNA) regulatory network of characteristic genes was created by Cytoscape and potential targeting drugs were obtained in the CTD database.

Results: 44 endometriosis-related differentially expressed genes were obtained from GSE25628 and the own dataset. Subsequently, LASSO and SVM-RFE algorithms identified four characteristic genes, namely ACLY, PTGFR, ADH1B, and MYOM1. The results of RT-PCR and western-blot were consistent with those of sequencing. The result of ROC curves indicated that the characteristic genes had powerful abilities in distinguishing EC samples from EU samples. Infiltrating immune cells analysis suggested that there was a certain difference in immune microenvironment between EC and EU samples. The characteristic genes were significantly correlated with specific differential immune cells between EC and EU samples. Then, a ceRNA regulatory network of characteristic genes was constructed and showed a total of 7, 11, 11, and 1 miRNA associated with ACLY, ADH1B, PTGFR, and MYOM1, respectively. Finally, we constructed a gene-compound network and mined 30 drugs targeting ACLY, 33 drugs targeting ADH1B, 13 drugs targeting MYOM1, and 12 drugs targeting PTGFR.

Conclusion: Comprehensive bioinformatic analysis was used to identify characteristic genes, and explore ceRNA regulatory network and potential therapeutic agents for endometriosis. Altogether, these findings provide new insights into the diagnosis and treatment of endometriosis.

The Double Engines and Single Checkpoint Theory of Endometriosis

Endometriosis is a chronic disease characterized by the ectopic localization of the endometrial tissue in the peritoneal cavity. Consequently, it causes local pathological changes and systemic symptoms, affecting at least one in every ten women. This disease is difficult to diagnose early, it is prone to dissemination, is difficult to eradicate, tends to recur, and is regarded as “a cancer of no kill”. Indeed, the development of endometriosis closely resembles that of cancer in the way of mutagenesis, pelvic spreading, and immunological adaptation. While retrograde menstruation has been regarded as the primary cause of endometriosis, the role of ovulation and menstrual stimuli in the development of endometriosis has long been overlooked. The development of ovarian and peritoneal endometrioses, similar to the development of high-grade serous carcinoma in the fallopian tube fimbriae with intraperitoneal metastasis, depends highly on the carcinogens released during ovulation. Moreover, endometriosis carries an extremely hypermutated genome, which is non-inferior to the ultra-mutated endometrial cancer. The hypermutation would lead to an overproduction of new proteins or neoantigens. Because of this, the developing endometriosis may have to turn on the PD-1/PDL-1 “self-tolerance” checkpoint to evade immune surveillance, leaving an Achilles tendon for an immune checkpoint blockade. In this review, we present the double engines and single checkpoint theory of the genesis of endometriosis, provide the current pieces of evidence supporting the hypothesis, and discuss the new directions of prevention and treatment.

The Regulatory Role of MicroRNAs on Phagocytes: A Potential Therapeutic Target for Chronic Diseases

An effective acute inflammatory response results in the elimination of infectious microorganisms, followed by a smooth transition to resolution and repair. During the inflammatory response, neutrophils play a crucial role in antimicrobial defense as the first cells to reach the site of infection damage. However, if the neutrophils that have performed the bactericidal effect are not removed in time, the inflammatory response will not be able to subside. Anti-inflammatory macrophages are the main scavengers of neutrophils and can promote inflammation towards resolution. MicroRNAs (miRNAs) have great potential as clinical targeted therapy and have attracted much attention in recent years. This paper summarizes the involvement of miRNAs in the process of chronic diseases such as atherosclerosis, rheumatoid arthritis and systemic lupus erythematosus by regulating lipid metabolism, cytokine secretion, inflammatory factor synthesis and tissue repair in two types of cells. This will provide a certain reference for miRNA-targeted treatment of chronic diseases.

Toll-like receptor signaling pathway triggered by inhibition of serpin A1 stimulates production of inflammatory cytokines by endometrial stromal cells

Endometriosis is characterized by the presence of inflamed and fibrotic endometrial tissue outside the uterine cavity. Previously, we found decreased SERPINA1 (alpha-1 antitrypsin) expression in endometriosis-like lesions in a mouse model of endometriosis, suggesting that it exacerbated inflammation in these lesions. However, the molecular mechanism(s) by which SERPINA1 affects expression of inflammatory factors and development of endometriotic lesions have not been fully characterized. To investigate the role of intracellular SERPINA1 in endometrial stromal cells (ESCs), we performed RNA sequence analysis using RNA extracted from ESCs in which SERPINA1 was knocked down. The analysis identified several toll-like receptor (TLR)-related factors as being upregulated. Silencing of SERPINA1 increased expression of TLR3 and TLR4 in ESCs, as well as several TLR signaling pathway components, including MYD88, IRAK1/4, interleukin (IL)-1β, and interferon (IFN)-β. TLR3 or TLR4 agonists increased expression of inflammatory factors in SERPINA1-knockdown ESCs, whereas TLR3 or TLR4 inhibitors decreased expression. In addition, treatment with recombinant IL-1β or IFN-β increased expression of MYD88 and inflammatory factors in ESCs. Immunohistochemical analysis of endometriotic tissues showed that TLR3, TLR4, and MYD88 were localized in endometriosis lesions. Taken together, the data suggest that reduced expression of SERPINA1 induces expression of inflammatory factors by ESCs, which in turn are associated with TLR3/4, IL-1β, and IFN-β signaling. Regulation of intracellular SERPINA1 levels in ESCs may be a strategy to inhibit inflammatory responses in endometriotic lesions.

Association between Endometrial Polyps and Chronic Endometritis: Is It Time for a Paradigm Shift in the Pathophysiology of Endometrial Polyps in Pre-Menopausal Women? Results of a Systematic Review and Meta-Analysis

BACKGROUND

Chronic endometritis (CE) and endometrial polyps (EPs) are common conditions in reproductive age women. CE is an infectious disorder of the endometrium characterized by signs of chronic inflammation at hysteroscopic and histological analyses. EPs are abnormal endometrial growths containing glands, stroma and blood vessels projecting from the lining of the uterus. During the last years, different authors have investigated the correlation between CE and EPs, with controversial results. The aim of this study was to summarize available evidence on the potential correlation between CE and EPs.

DESIGN

Systematic literature review and meta-analysis.

METHODS

Observational-studies were identified by searching electronic databases from their inception to September 2021. Only studies on pre-menopausal women were included. Statistical analysis was performed using MedCalc 16.4.3 (Ostend, Belgium) and Review Manager version 5.3 (Nordic Cochrane Centre, Cochrane Collaboration). The summary measures were reported as pooled proportion or odds ratio (OR) with 95% confidence interval (CI). The primary outcome was to evaluate the prevalence of CE in women with EPs. The secondary outcome was to determine the prevalence of CD-138-positive EPs among EPs. Tertiary outcomes were to compare the prevalence of CE in women with EPs versus women with a non-polypoid endometrium and to compare the prevalence of CE in women with a single EP versus women with multiple EPs.

RESULTS

Eight observational studies (n = 3225 patients) were included in quantitative synthesis. Pooled prevalence of CE among women with EPs was 51.35% (95% CI, 27.24-75.13%). Pooled proportion of CD-138-positive EPs among EPs was 70.73% (95% CI, 55.73-83.68%). Women with EPs showed higher prevalence of CE compared to women without EPs (OR 3.07, 95% CI 1.59-5.95). Women with ≥3 EPs had higher prevalence of CE then women with a single EP (OR 3.43, 95% CI 1.83-6.46).

CONCLUSIONS

In pre-menopausal women, CE and EPs may have a dependent relationship and may represent two consequent steps of a common pathological process.

Macrophages in tumor: An inflammatory perspective

Inflammation is a part of carefully co-ordinated healing immune exercise to eliminate injurious stimuli. However, in substantial number of cancer types, it contributes in shaping up of robust tumor microenvironment (TME). Solid TME promotes infiltration of tumor associated macrophages (TAMs) that contributes to cancer promotion. TAMs are functionally heterogeneous and display an extraordinary degree of plasticity, which allow 'Switching' of macrophages into an 'M2', phenotype, linked with immunosuppression, advancement of tumor angiogenesis with metastatic consequences. In contrary to the classical M1 macrophages, these M2 TAMs are high-IL-10, TGF-β secreting-'anti-inflammatory'. In this review, we will discuss the modes of infiltration and switching of TAMs into M2 anti-inflammatory state in the TME to promote immunosuppression and inflammation-driven cancer.

The High Expression of RRM2 Can Predict the Malignant Transformation of Endometriosis

INTRODUCTION

A large number of epidemiological studies have revealed that women with endometriosis (EMS) have a higher risk of developing endometriosis-associated ovarian cancer (EAOC). At present, there are few studies on predicting the malignant transformation of ovarian endometriosis (OE). The purpose of this study is to identify and verify the molecules that may be able to predict the malignant transformation of OE.

METHODS

The gene expression profiles of ovarian cancer and OE were downloaded from Gene Expression Omnibus (GEO), and a common hub gene ribonucleotide reductase M2 (RRM2) was identified. A total of 44 patients with EAOC and 44 with OE were enrolled in this study. Immunohistochemistry (IHC) and quantitative reverse transcription polymerase chain reaction (RT-qPCR) were used to detect the expression of RRM2, while the relationship between RRM2 and Ki-67 was analyzed by IHC co-localization.

RESULTS

Bioinformatics analysis showed that the expression of RRM2 was low in EMS and high in ovarian cancer. RRM2 was obviously positively expressed in eutopic endometrium (EU), ectopic endometrium (EC), and cancer tissues of EAOC patients. The IHC signal and mRNA levels of RRM2 were higher in the EC of EAOC patients compared with OE patients (P < 0.01). In addition, there was a correlation between the expression of RRM2 and Ki-67 in EC of EAOC patients (P < 0.01).

CONCLUSION

The upregulated expression of RRM2 in the EC of OE patients may indicate malignant transformation. High expression of RRM2 promotes abnormal proliferation of histiocytes. RRM2 can be used as a potential marker of malignant transformation of OE.

Correlation of calprotectin serum levels with degrees of endometriosis: A cross-sectional study

Background

Endometriosis is closely associated with delayed diagnosis due to the lack of a definitive and sensitive noninvasive approach. The use of calprotectin in inflammatory process has been demonstrated in various inflammatory diseases. Calprotectin has a significant correlation with high-sensitivity C-reactive protein (hs-CRP) and could be used as an inflammatory marker. No study thus far has evaluated the correlation between calprotectin and endometriosis.

Objective

To determine the correlation of calprotectin with the degree of endometriosis in order to help clinicians in establishing better early detection and management.

Materials and Methods

In this cross-sectional study, 46 women referred to the Cipto Mangunkusumo, Fatmawati, and Persahabatan Hospitals in Jakarta, Indonesia between July 2017 and April 2018 were enrolled, and their blood serum were taken a day before surgery. Calprotectin serum level was treated using the PhicalⓇ ELISA method. After the diagnosis of endometriosis was confirmed through pathological examination, the final diagnosis of endometriosis could be established. The degree of endometriosis was classified according to the revised American Society for Reproductive Medicine (ASRM) classification.

Results

The prevalence of minimal, mild, moderate, and severe degrees of endometriosis were 15.2, 39.1, 34.8, and 10.9%, respectively. The median serum calprotectin levels for minimal, mild, moderate, and severe endometriosis were 138.98, 121.49, 124.16, and 122.82 mg/mL, respectively. No correlation was observed between calprotectin and the degrees of endometriosis (r = –0.16, p = 0.278).

Conclusion

There is no correlation between calprotectin serum levels and the degrees of endometriosis.

Endometriosis Susceptibility to Dapsone-Hydroxylamine-Induced Alterations Can Be Prevented by Licorice Intake: In Vivo and In Vitro Study

Endometriosis, an estrogen-dependent chronic gynecological disease, is characterized by a systemic inflammation that affects circulating red blood cells (RBC), by reducing anti-oxidant defenses. The aim of this study was to investigate the potential beneficial effects of licorice intake to protect RBCs from dapsone hydroxylamine (DDS-NHOH), a harmful metabolite of dapsone, commonly used in the treatment of many diseases. A control group (CG, n = 12) and a patient group (PG, n = 18) were treated with licorice extract (25 mg/day), for a week. Blood samples before (T₀) and after (T₁) treatment were analyzed for: i) band 3 tyrosine phosphorylation and high molecular weight aggregates; and ii) glutathionylation and carbonic anhydrase activity, in the presence or absence of adjunctive oxidative stress induced by DDS-NHOH. Results were correlated with plasma glycyrrhetinic acid (GA) concentrations, measured by HPLC–MS. Results showed that licorice intake decreased the level of DDS-NHOH-related oxidative alterations in RBCs, and the reduction was directly correlated with plasma GA concentration. In conclusion, in PG, the inability to counteract oxidative stress is a serious concern in the evaluation of therapeutic approaches. GA, by protecting RBC from oxidative assault, as in dapsone therapy, might be considered as a new potential tool for preventing further switching into severe endometriosis.

PPARγ Agonists: Emergent Therapy in Endometriosis

Endometriosis is one of the major gynecological diseases of reproductive-age women. This disease is characterized by the presence of glands and stroma outside the uterine cavity. Several studies have shown the major role of inflammation, angiogenesis, adhesion and invasion, and apoptosis in endometriotic lesions. Nevertheless, the mechanisms underlying endometriotic mechanisms still remain unclear and therapies are not currently efficient. The introduction of new agents can be effective by improving the condition of patients. PPARγ ligands can directly modulate these pathways in endometriosis. However, data in humans remain low. Thus, the purpose of this review is to summarize the potential actions of PPARγ agonists in endometriosis by acting on inflammation, angiogenesis, invasion, adhesion, and apoptosis.

A systematic review of toll-like receptors in endometriosis

INTRODUCTION

The pathogen-associated molecular patterns and the danger-associated molecular patterns are possibly responsible for the activation of the inflammatory process in endometriosis through the activation of toll-like receptors (TLRs).

OBJECTIVE

The aim of this systematic review was to critically analyze the findings of published articles on TLRs in endometriosis.

METHODS

The keywords used were "endometriosis" and "toll-like" and the search was performed in Pubmed, Scielo and Lilacs databases. This study followed the PRISMA guidelines and the risk of bias of articles was conducted by Newcastle-Ottawa scale (NOS).

RESULTS

Overall, the studies analyzed in this review point toward an increased expression of TLRs two, four and nine in women with endometriosis. Among all TLRs, TLR4 was the most cited receptor.

CONCLUSION

Despite the evidence demonstrating elevated TLR levels in endometriosis, the relationship with the disease is still unclear and needs to be clarified in further studies about innate immune response.

Evaluation of Toll-like receptor 3 (TLR3) signaling pathway genes and its genetic polymorphisms in ectopic and eutopic endometrium of women with endometriosis

OBJECTIVE

Toll-like receptors (TLRs, as members of the innate immune system) are expressed in the human endometrium and their aberrant regulation and expression are involved in the pathogenesis of endometrial diseases. This study is aimed at evaluation of TLR3 signaling pathway genes and its genetic changes in endometriosis patients.

MATERIALS AND METHODS

Blood samples were collected from 83 endometriosis patients and 93 healthy fertile women and PCR was performed in blood-derived DNA for detection of SNP of TLR3. Also, ectopic (EC) and eutopic (EU) endometrial biopsies were obtained from endometriosis patients (n = 20), as well as endometrium from healthy women (n = 16, CE). Q-PCR was performed for determination of mRNA expression level of TLR3 signaling pathway genes (TLR3, TICAM, NF-kB1A, CXCL10, IRF3, IFN-B1, IL-6 and IL-8). Also, serum protein levels of TLR3, IFN-β, IL-6 and IL-8 were determined using ELISA.

RESULTS

The mRNA expression levels of TLR3, NF-kB1A, IFN-B1, IRF3, TICAM1, IL-6 and IL-8 were significantly higher in EU compared to ectopic ones and also compared to CE. SNPs frequency (rs3775291 and rs3775290) was not significantly different between patients and controls. Serum protein levels of TLR3, IFN-β, IL-6 and IL-8 were significantly increased in endometriosis patients.

CONCLUSION

Significant changes were observed in the expression of IL-6 and IL-8 cytokines and other genes in TLR3 cascade in diseased EU, demonstrating that EU similarly to EC is in an intensive inflammatory state. These fundamental alterations in the concept of immune response in EU may lead to its activation, escapes from apoptosis, and displaced implantation of the endometrium.

Possible role of microbiome in the pathogenesis of endometriosis

INTRODUCTION

There is an urgent necessity to explore the complex pathophysiological nature of endometriosis, which may enable the rationale for new diagnostic and therapeutic strategies to be discovered. This systematic review aimed to clarify the bidirectional relationship between endometriosis and the microbiome and evaluate if the microbiome may be involved in endometriosis's pathogenesis, establishing a potential connection between the different studies.

EVIDENCE ACQUISITION

Studies were identified through a systematic literature search of papers that evaluated the microbiomes of human or other animal species with endometriosis and of those without in the electronic database PubMed/Medline, and Embase without a date restriction. We included all cohort studies focusing on the interaction between endometriosis and the microbiomes of humans or other mammals, evaluating if the microbiome may be involved in endometriosis's pathogenesis.

EVIDENCE SYNTHESIS

Endometriosis appears to be associated with elevated levels of different microorganisms across various microbiome sites. An ineffective immune response seems to play a key role in endometriosis pathogenesis, and there is some scientific proof to state that the immune response may be modulated by the microbiome. Interestingly, nine studies of our review detected species belonging to the phyla Proteobacteria, Bacteroidetes, and Negativicutes characterized by Gram-negative staining, that were significantly increased in endometriosis cohorts.

CONCLUSIONS

Laboratory and clinical investigations indicate that hosts' microbiome profiles with and without endometriosis can be significantly different. To further our understanding of the relationships between endometriosis and the host microbiome, more studies are necessary.

Eutopic endometrium from women with endometriosis and chlamydial endometritis share immunological cell types and DNA repair imbalance: A transcriptome meta-analytical perspective

The aim of this study was to identify the key similarities between the eutopic endometrium of women with endometriosis and chlamydia-induced endometritis taking into account tissue microenvironment heterogeneity, transcript gene profile, and enriched pathways. A meta-analysis of whole transcriptome microarrays was performed using publicly available data, including samples containing both glandular and stromal endometrial components. Control samples were obtained from women without any reported pathological condition. Only samples obtained during the proliferative menstrual phase were included. Cellular tissue heterogeneity was predicted using a method that integrates gene set enrichment and deconvolution approaches. The batch effect was estimated by principal variant component analysis and removed using an empirical Bayes method. Differentially expressed genes were identified using an adjusted p-value < 0.05 and fold change = 1.5. The protein-protein interaction network was built using the STRING database and interaction score over 400. The Molecular Signatures Database was used to analyse the functional enrichment analysis. Both conditions showed similarities in cell types in the microenvironment, particularly CD4⁺ and CD8⁺ Tem cells, NKT cells, Th2 cells, basophils, and eosinophils. With regards to the regulation of cellular senescence and DNA integrity/damage checkpoint, which are commonly enriched pathways, 21 genes were down-regulated and directly related to DNA repair. Compared to the endometriosis samples, some chlamydial endometritis samples presented a lack of enriched immune pathways. Our results suggest that both conditions show similar distributions of microenvironment cell types, the downregulation of genes involved in DNA repair and cell cycle control, and pathways involved in immune response evasion.

Inflammation related to high-mobility group box-1 in endometrial ovarian cyst

Endometriosis is a chronic inflammatory disease often associated with dysmenorrhea, infertility, adenomyosis, and endometrial ovarian cyst (EOC). In particular, EOC can sometimes become malignant in a longitudinal follow-up. This study aimed to investigate the involvement of high-mobility group box-1 (HMGB1) in an inflammatory milieu and the characteristics of immune cells in EOC. The samples were obtained from patients who underwent ovarian cystectomy for benign ovarian cyst. The participants were divided into two groups: patients with EOC (EOC group) and those without EOC (nEOC group). We divided a part of the removed ovary into small sections and isolated the tissue cells. Thereafter, the cytoplasmic HMGB1 levels in DCs, macrophages, and non-immune cells were analyzed by flow cytometry. We also evaluated the proportions of immune, T, NK, iNKT, NK, and regulatory T (Treg) cells. Results showed that the DCs, macrophages, and non-immune cells of EOC had significantly higher cytoplasmic HMGB1 levels than those of nEOC. The expression of CD69 and CD107a on CD8⁺ T and CD4⁺ T cells of EOC was also more enhanced than that of nEOC. Furthermore, the M2 macrophages and Tregs highly accumulated in EOC. These results indicate that HMGB1 may aggravate chronic inflammation related to T-cell activation and simultaneously facilitate development of the immunosuppressive milieu in EOCs.

Elucidating the role of long intergenic non-coding RNA 339 in human endometrium and endometriosis

Endometriosis is a complex disease, influenced by genetic factors. Genetic markers associated with endometriosis exist at chromosome 1p36.12 and lead to altered expression of the long intergenic non-coding RNA 339 (LINC00339), however, the role of LINC00339 in endometriosis pathophysiology remains unknown. The aim of this work was to characterize the expression patterns of LINC00339 mRNA in endometrium and endometriotic lesions in situ and to determine the functional role of LINC00339 in human endometrium. We employed RNA-sequencing (RNA-seq), quantitative RT-PCR and in situ hybridization to investigate the abundance of LINC00339 transcripts in endometrium and endometrial cell lines and to describe the pattern and localization of LINC00339 expression in endometrium and endometriotic lesions. LINC00339 mRNA expression was manipulated (overexpressed and silenced) in endometrial stromal cell lines and RNA-seq data from overexpression models were analysed using online bioinformatics platforms (STRING and Ingenuity Pathway Analysis) to determine functional processes. We demonstrated the expression of LINC00339 in endometriotic lesions for the first time; we found LINC00339 expression was restricted to the lesion foci and absent in surrounding non-lesion tissue. Furthermore, manipulation of LINC00339 expression in endometrial stromal cell lines significantly impacted the expression of genes involved in immune defence pathways. These studies identify a novel mechanism for LINC00339 activity in endometrium and endometriosis, paving the way for future work, which is essential for understanding the pathogenesis of endometriosis.

Insights into the role of complement system in the pathophysiology of endometriosis

Endometriosis (EM) is a gynecologic disorder characterized by the presence of endometrium-like tissue outside of normal location that affects up to 10 % of all women in reproductive age. The pathogenesis of endometriosis is not completely known. The relationship between complement and EM has already been demonstrated in some studies, indicating an important role in the pathophysiology of the disease, however, researches are scarce and sometimes controversial. The objective of this review is to bring state-of-the-art knowledge on the subject and promote better understanding of the complement system role in the pathophysiology of EM. We searched in databases up to December 2020 and found 1213 articles that were screened, from which were selected 54 articles from title and abstract. We found that there is a dysfunction of the immune system on endometriosis, including the complement system. Apparently, the complement system is dysregulated in endometriosis and several proteins of the three complement pathways presented serum levels altered in women with endometriosis compared with those without the disease. The most studied protein is C3. Future investigations on the innate immune response and complement system could offer a further understanding on the inflammatory pathogenesis of EM, which will support a new therapeutic plan.

Cytokines, Angiogenesis, and Extracellular Matrix Degradation are Augmented by Oxidative Stress in Endometriosis

Background

The effect of the interplay among inflammation, angiogenesis, extracellular matrix (ECM) degradation, and oxidative stress (OS) on the pathogenesis of endometriosis remains unclear. Previously, we demonstrated the role of OS in endometriosis. Here, we performed a comprehensive investigation of several molecules involved in inflammation, angiogenesis, and ECM degradation in women with endometriosis to study their interplay with OS.

Methods

Blood samples were collected from women with endometriosis (N=80), as well as from women with tubal factor infertility as controls (N=80). Interleukin (IL)-1β, tumor necrosis factor-alpha, interferon-gamma, transforming growth factor-beta, IL-4, −10, −2, −6, −8, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, −9, tissue inhibitor of metalloproteinases (TIMP)-1, −2, and cyclooxygenase (COX)-2 levels in serum samples were measured using an ELISA. Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in peripheral blood mononuclear cells was measured using flow cytometry.

Results

Cytokines, VEGF, MMPs, and COX-2 were significantly higher and TIMPs were significantly lower in patients with endometriosis. Multivariate statistical analysis indicated that IL-10 was the most significant variable capable of discriminating endometriosis samples from controls.

Conclusions

Deregulation of NF-κB activation by OS affects the expression of various cytokines in endometriosis. Elevated cytokine levels further up-regulate IL-10, which subsequently activates the MMPs, leading to excessive ECM degradation and angiogenesis. Moreover, IL-10 emerged as the most important molecule involved in the pathogenesis of endometriosis. Measurement of these molecules may help in better management of the patients with endometriosis.

Hemoglobin-induced continuous activation of macrophages in endometriotic cysts: a potential mechanism of endometriosis development and carcinogenesis

Endometriosis is a chronic inflammatory disease. Endometriotic cysts contain hemoglobin (Hb) and infiltrated macrophages, indicating that the metabolism of Hb by macrophages may play an important role in the inflammation of endometriotic cysts. In this study, we investigated the distribution of immune cells and CD163 (Hb receptor)-positive cells in the endometriotic cyst wall using immunohistochemistry. We also examined the role of macrophage activation by Hb on the pathogenesis of endometriotic cysts by measuring the cytokine concentration in the cystic fluids and macrophage-culture supernatant using ELISA. Macrophages were the most prominent immune cells observed in the endometriotic cysts and were differentially distributed in the different histological areas of the cyst wall. The localization of CD163-positive macrophages was restricted to the hemorrhagic and outer areas in the cyst wall. High concentrations of IL-6 and CCL2 were found in the cystic fluids, and inflammatory cytokines (IL-6, TNF-α, and CCL2) were secreted from macrophages on stimulation by Hb. IL-6 is a promotional factor for endometriotic stromal cells and ovarian clear cell carcinoma, the most common histological subtype of endometriosis-related ovarian cancer, hence, the continuous activation of macrophages by Hb could be a potential mechanism underlying endometriosis development and carcinogenesis.

Increased ApoE Expression in Follicular Fluid and the ApoE Genotype Are Associated With Endometriosis in Chinese Women

More than 10% of women suffer from endometriosis (EMT) during their reproductive years. EMT can cause pain and infertility and requires further study from multiple perspectives. Previous reports have indicated that an increase inapolipoprotein E (ApoE) may be associated with a lower number of retrieved mature oocytes in older women, and an association between ApoE and spontaneous pregnancy loss may exist in patients with EMT. The purpose of this study was to investigate the existence of an increase in ApoE in follicular fluid (FF) and the possible relationship between ApoE and EMT in Chinese women. In the current study, 217 Chinese women (111 control subjects and 106 EMT patients) were included. The ApoE genotypes were identified by Sanger sequencing. We found that ApoE expression in FF was higher in patients with EMT than in the control group. In addition, a significant difference in ApoE4 carriers (ϵ3/ϵ4, ϵ4/ϵ4) was found between the control subjects and the patients with EMT. Furthermore, a nonparametric test revealed significant differences in the numbers of blastocysts and high-quality blastocysts, but not the hormone levels of FSH, LH, and E2, between the two groups. We also established a multifactor (BMI, high-quality blastocysts, and ϵ4) prediction model with good sensitivity for identifying patients who may suffer from EMT. Our results demonstrate that ApoE expression in FF is increased in EMT, the ApoE-ϵ4 allele is significantly linked to EMT, and a combined analysis of three factors (BMI, high-quality blastocysts, and ϵ4) could be used as a predictor of EMT.

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.

Impaired pathogen-induced autophagy and increased IL-1β and TNFα release in response to pathogenic triggers in secretory phase endometrial stromal cells of endometriosis patients

RESEARCH QUESTION

It is not clear whether innate immunity along with autophagy is altered in endometrial cells of patients with endometriosis.

DESIGN

This study evaluated the effects of lipopolysaccharide (LPS) or polyinosinic:polycytidylic acid (poly I:C) stimulation on autophagy induction, pro-IL-1β expression, and secretion of interleukin-1β (IL-1β) and tumour necrosis factor-α (TNFα) in endometrial epithelial and/or stromal cells of patients with endometriosis (EE-endo, ES-endo, respectively), those of patients with hydrosalpinx (EE-hydro, ES-hydro, respectively) and those of healthy fertile women (EE-healthy, ES-healthy, respectively), with and without inhibition of autophagy by autophagy-related (ATG)13 gene small interfering RNA (siRNA).

RESULTS

Stimulation with either LPS or poly I:C triggered autophagy in EE/ES-healthy, whereas no significant induction was observed in either EE/ES-endo or EE/ES-hydro. In EE- and/or ES-healthy, IL-1β and/or TNFα secretion after stimulation with LPS or poly I:C was significantly higher in cells with ATG13 knockdown compared with those with siRNA control (P < 0.03), whereas no significant difference was observed in either EE/ES-endo or EE/ES-hydro. In the secretory phase ES-endo without autophagy inhibition, IL-1β and TNFα secretion were significantly higher compared with those of ES-healthy after stimulation with either LPS or poly I:C for 4 h (P < 0.001) and for 24 h (P < 0.01).

CONCLUSION

Pathogen-induced autophagy was impaired in EE/ES-endo. Increased IL-1β and TNFα release in response to pathogenic triggers in the secretory phase ES-endo may result in the development of an inflammatory uterine microenvironment detrimental to successful embryo implantation.

Endometriosis Associated Infertility: A Critical Review and Analysis on Etiopathogenesis and Therapeutic Approaches

Endometriosis represents a frequently diagnosed gynecological affliction in the reproductive timespan of women, defined by symptoms ranging from pelvic pain to infertility. A complex interplay between the genetic profile, hormonal activity, menstrual cyclicity, inflammation status, and immunological factors define the phenotypic presentation of endometriosis. To date, imaging techniques represent the gold standard in diagnosing endometriosis, of which transvaginal ultrasonography and magnetic resonance imaging bring the most value to the diagnostic step. Current medical treatment options for endometriosis-associated infertility focus on either stimulating the follicular development and ovulation or on inhibiting the growth and development of endometriotic lesions. Techniques of assisted reproduction consisting of superovulation with in vitro fertilization or intrauterine insemination represent effective treatment alternatives that improve fertility in patients suffering from endometriosis. Emerging therapies such as the usage of antioxidant molecules and stem cells still need future research to prove the therapeutic efficacy in this pathology.

The -1195A>G polymorphism in Ciclooxygenase-2 gene is associated with lower risk of endometriosis

OBJECTIVES

This study aimed to evaluate the potential role of the PTGS2 single nucleotide polymorphisms (SNPs) -1195 A>G and +8473 T>C in endometriosis' development, and characterizing their association with the prognostic features of the disease.

STUDY DESIGN

DNA from 254 women with endometriosis and 267 controls, recruited from two reference hospitals from the Brazilian public health system, were genotyped using TaqMan allelic discrimination assays. The association between SNPs and endometriosis features was evaluated by multivariate logistic regression, using the adjusted odds ratios (OR) with their respective 95% confidence intervals (95% CI).

RESULTS AND CONCLUSION

There were significant differences between cases and controls regarding age (P < 0.001), body mass index (BMI) (P = 0.001), educational level (P < 0.001), physical activity (P = 0.003), smoking status (P < 0.001), contraception use (P = 0.02), family history of endometriosis (P = 0.002) and all symptoms (P < 0.001). The distribution of -1195 A > G was statistically different between the groups, suggesting a lower risk of developing the disease for the carriers of the -1195 GG genotype (OR = 0.19; 95% CI = 0.04 - 0.93). No differences were found for the +8473 T>C between the two groups and neither in prognostic features of the disease for both PTGS2 SNPs. In conclusion, PTGS2 -1195A>G SNP was negatively associated with development of endometriosis and the two groups were statistically different regarding age, BMI, educational level, physical activity, smoking status, contraception use, history of endometriosis and all endometriosis symptoms.

Serum Leptin as a Marker for Severity of Endometriosis

Background

Endometriosis a disease of theories, and one of the important causes of chronic pelvic pain, dysmenorrhea, dyspareunia, and subfertility. Surgery is the mainstay step for the diagnosis; noninvasive test is the goal in the future. Aim of Study. To test the role of serum leptin in determination of severity of endometriosis. Study Design. A cross-sectional study done in Al-Yarmouk Teaching Hospital from 1st of January 2018 to 1st of January 2019.

Methods

60 BMI-matched patients were involved in the study. A study group of 30 patients were operated either by laparoscopy or laparotomy for many reasons diagnosed as endometriosis by histopathology, and 30 normal women as a control group underwent elective surgery. Blood sample was taken from all patients in the theater room when laparoscopy finding went with endometriosis, and classifying according to surgical staging of endometriosis, the level of serum leptin was measured by ELISA using Human LEP (Leptin) ELISA Kit. The recording of finding of laparoscopy after conforming of diagnosis by histopathology was compared with the result of serum leptin.

Result

The result shows no significant difference between the two groups regarding parity and age; however, the level of serum leptin was significantly high in the endometriosis group than in the control group. The P value was less than 0.05. Also, the result shows no significant differences between serum leptin in both groups according to the symptom but there was a significant difference with surgical staging. The mean of the level of serum leptin in stage 1 was 214.8, while it was 340.3 in stage 4.

Conclusion

Serum leptin can be used as a marker of severity of endometriosis.

Retrofractamide C Derived from Piper longum Alleviates Xylene-Induced Mouse Ear Edema and Inhibits Phosphorylation of ERK and NF-κB in LPS-Induced J774A.1

Many studies have reported the biological activities of retrofractamide C (RAC). However, few studies have investigated the anti-inflammatory effect of RAC. In the present study, we investigated the anti-inflammatory effect of RAC using lipopolysaccharide (LPS)-induced J774A.1 cells and a xylene-induced mouse ear edema model. Treatment with RAC decreased LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) secretion and inducible NO synthase (iNOS) and cyclooxygenase 2 (COX2) protein expression. It also downregulated the LPS-induced production of interleukin-1β (IL-1β) and interleukin-6 (IL-6) but not tumor necrosis factor α (TNF-α). In the LPS-induced signaling pathway, RAC inhibited the phosphorylation of extracellular signal-regulated kinase (ERK) and nuclear factor kappa light chain enhancer of activated B cells (NF-κB) but not c-Jun N-terminal kinase (JNK) or p38. In a xylene-induced mouse ear edema model, RAC treatment alleviated edema formation and inflammatory cell infiltration. In conclusion, the present study indicates that RAC has the potential to have anti-inflammatory effects and could be a prospective functional food.

Harmful and beneficial effects of inflammatory response on reproduction: sterile and pathogen-associated inflammation

In reproduction, inflammatory processes play important roles in the development of many pregnancy complications such as preterm labor/birth, recurrent pregnancy loss, recurrent implantation failure, and preeclampsia. Inflammation can be initiated by both microbial and non-microbial causes. Bacterial infection in the feto-maternal interface and uterus can provoke preterm labor/birth, miscarriage, and chronic endometritis. By contrast, inflammation without infection, or 'sterile inflammation,' can also lead to many kinds of complications, such as preterm labor/birth, miscarriage, or preeclampsia. Aberrant inflammation is facilitated by immune cells such as macrophages, dendritic cells, natural killer cells, and invariant natural killer T cells. In addition, cytokines, chemokines, and several kinds of inflammatory mediators are involved. On the other hand, appropriate inflammation is required for a successful offspring during the progression of the entire pregnancy. Herein, we discuss the relation between pregnancy and inflammation with immunological alterations. Understanding the role of inflammation in complications during pregnancy may establish new perspectives of the progress of normal pregnancy as well as treatments during pregnancy complications.

Toll-Like Receptor 2 Expression as a New Hallmark of Advanced Endometriosis

Recent evidence suggests that immunological aspects play a pivotal role in this disorder. Toll-like receptor 2 (TLR2) is crucial in recognizing microbial infections and mediating innate immune response. The objective of our study was to rate with flow cytometry the levels of several subsets of dendritic cells, monocytes, and basic peripheral blood lymphocytes expressing TLR2, aiming at the determination of a possible correlation between the expression of TLR2 and the clinical outcomes of endometriosis in 40 patients and 40 age-matched healthy women. Our study showed the importance of TLR2 expression, mainly on myeloid dendritic cells (mDCs) and B cells in patients with endometriosis. Both mDCs BDCA1+CD19-TLR2+ and B lymphocytes CD19+TLR-2+ proved useful in the differentiation of affected individuals with stages 3–4 of the disease (area under the receiver operating characteristic curve /AUC/ = 0.96, p < 0.0001 for mDCs; AUC = 0.78, p = 0.0001 for B lymphocytes), and those presenting adhesion (AUC = 0.92, p < 0.0001 for mDCs; AUC = 0.82, p < 0.0001 for B lymphocytes) or infertility (AUC = 0.83, p < 0.0001 for mDCs; AUC = 0.73, p = 0.006 for B lymphocytes). Our findings suggest that the levels of TLR2-expressing cells, particularly mDCs and B lymphocytes, may be an effective biomarker of endometriosis, because the disease currently lacks clinically useful noninvasive biomarkers enabling early and cost-effective diagnosis.

Genetic, Epigenetic, and Steroidogenic Modulation Mechanisms in Endometriosis

Endometriosis is a chronic gynecological disease, affecting up to 10% of reproductive-age women. The exact cause of the disease is unknown; however, it is a heritable condition affected by multiple genetic, epigenetic, and environmental factors. Previous studies reported variations in the epigenetic patterns of numerous genes known to be involved in the aberrant modulation of cell cycle steroidogenesis, abnormal hormonal, immune and inflammatory status in endometriosis, apoptosis, adhesion, angiogenesis, proliferation, immune and inflammatory processes, response to hypoxia, steroidogenic pathway and hormone signaling are involved in the pathogenesis of endometriosis. Accumulating evidence suggest that various epigenetic aberrations may contribute to the pathogenesis of endometriosis. Among them, DNA methyltransferases, histone deacetylators, and non-coding microRNAs demonstrate differential expression within endometriotic lesions and in the endometrium of patients with endometriosis. It has been indicated that the identification of epigenetic differences within the DNA or histone proteins may contribute to the discovery of a useful prognostic biomarker, which could aid in the future earlier detection, timely diagnosis, and initiation of a new approach to the treatment of endometriosis, as well as inform us about the effectiveness of treatment and the stage of the disease. As the etiology of endometriosis is highly complex and still far from being fully elucidated, the presented review focuses on different approaches to identify the genetic and epigenetic links of endometriosis and its pathogenesis.

Features of local immunity in women with endometriosis and genital infection

Introduction. External genital endometriosis is an inflammatory estrogen-dependent disease characterized by implantation and proliferation of endometrial tissue outside the uterus, accompanied by increased production of proinflammatory cytokines, prostaglandins, components of the complement, hydrolytic enzymes, increased angiogenesis and anomalies of ectopic endometrium. According to implantation theory, external genital endometriosis develops from viable endometrial cells transferred retrogradely through the fallopian tubes to the abdominal cavity during menstruation, while a disturbed local immunity is an important factor in its pathogenesis. Genital pathogens may be involved in the formation of the immune environment of the peritoneal cavity in women with endometriosis.Purpose. To study the peculiarities of local immunity in women with external genital endometriosis and genital infection pathogens.Materials and methods. 159 women with external genital endometriosis were examined. The total number of leukocytes, the absolute and relative number of viable cells, counts of neutrophils, macrophages and their functional activity, the level of IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IFNα, IFNγ, TNFα in the peritoneal fluid were evaluated. The study of local immunity was performed in women with endometriosis, stage 1—2 and 3—4, depending on detected genital pathogens. Chlamydia trachomatis, Ureaplasma spp., Mycoplasma genitalium, HSV1,2/CMV, high carcinogenic risk HPV were analyzed by using PCR in samples collected from the endometrium, peritoneal fluid, and endometrioid heterotopies. Statistical processing was performed by using the IBM SPSS Statistics Version 22.2 statistical analysis software package.Results. In the presence of HPV and Ureaplasma spp. in women with endometriosis, stage 1—2, the decreased functional activity of peritoneal neutrophils and macrophages was found. At 3—4 stage, a correlation analysis revealed that detected HPV and Ureaplasma spp. obtained increased both pro-inflammatory and anti-inflammatory cytokines in the peritoneum. However, the higher activity of Th-2 cells in the peritoneal fluid secreting IL-4 and IL-10 and suppressing cellular immunity, was observed in HPV-positive samples. In addition, HPV also correlated with a decreased IL-2 and IL-4 levels.Conclusions. The most prominent changes in the immunological parameters from peritoneal fluid samples were observed in case of detected genital infection pathogens, particularly HPV. Thus, immune disturbances emerged upon bacterial and viral pathogen detection may contribute to the implantation of endometrial cells in the pelvic organs and disease progression.

Fecal Microbiota Transplantation: A Potential Tool for Treatment of Human Female Reproductive Tract Diseases

The gastro-intestinal tract is an extensive organ involved in several activities, with a crucial role in immunity. Billions of commensal and transient microorganisms, known as the gut microbiota, and potential pathogens, which are constantly stimulating intestinal immunity, colonize the intestinal epithelial surface. The gut microbiota may be regarded as analogous to a solid organ with multiple different functions. In the last decade, many studies have demonstrated that intestinal bacteria can be a decisive factor in the health-disease balance of the intestine, and they can also be responsible for illnesses in other locations. For this reason, fecal microbiota transplantation (FMT) represents an important therapeutic option for Clostridium difficile infections and hold promise for different clinical conditions, such as multiple sclerosis, autism, obesity, and other systemic diseases. FMT consists of the infusion of a fecal suspension from a healthy donor to a recipient in order to restore gut flora alterations. Similar to the gut, the female reproductive tract is an example of a very complex biological ecosystem. Recent studies indicate a possible relationship between the gut and female tract microbiota, associating specific intestinal bacteria patterns with genital female diseases, such as polycystic ovary syndrome (PCOS), endometriosis and bacterial vaginosis (BV). FMT could represent a potential innovative treatment option in this field.

Ureaplasma Urealyticum Infection Contributes to the Development of Pelvic Endometriosis Through Toll-Like Receptor 2

Endometriosis is a chronic gynecological disorder, characterized by the presence of ectopic endometrial tissue outside the uterine cavity. Among several hypotheses, Sampson's theory of retrograde menstruation is still applicable. Recent studies have reported the importance of inflammation among endometrial tissue, the peritoneum, and immune cells. However, less is known regarding the role of bacterial infection in the pathophysiology of endometriosis. We hypothesized that Ureaplasma urealyticum infection might contribute to the development of endometriosis by inducing the production of inflammatory mediators by peritoneal mesothelial cells (PMCs), possibly through TLR2. Hence, our objective was to reveal whether PMC infection by U. urealyticum is associated with endometriosis. Moreover, we aimed to demonstrate the molecular mechanism involved in this relationship. We developed a new infection-induced mouse model of endometriosis with wild type and Tlr2-deficient mice. Based on the in vivo mouse model, U. urealyticum-infected mice showed significantly increased numbers and sizes of ectopic endometriotic lesions. U. urealyticum upregulated not only the production of IL-6, CXCL1, and CCL2, but also the expression of ICAM-1, VCAM-1, and MMP2 in murine PMCs. Similarly, endometrial stromal cells dose-dependently produced IL-6, CXCL1, and CCL2 in response to U. urealyticum infection. The series of inflammatory responses in PMCs was mediated mainly through TLR2. The phosphorylation of ERK and JNK was observed when U. urealyticum was added to PMCs and knock out of Tlr2 inhibited these MAPKs phosphorylation. Based on our co-culture study, U. urealyticum-infected PMCs exhibited significantly increased attachment to ESCs compared with uninfected PMCs. Collectively, U. urealyticum infection promotes the development of endometriosis by increasing inflammatory mediators, adhesion molecules, and MMP-2 expression in PMCs through TLR2 signaling. Through our results, we present a theory that infection-induced pelvic inflammation contributes to the initiation and progression of endometriosis. Appropriate treatment of reproductive tract infection may decrease the prevalence of endometriosis.

Vaginal endometrial stromal sarcoma: A literature review

Vaginal endometrial stromal sarcoma (VESS) is a rare disease. To the best of our knowledge, there have only been a few reported cases in the literature. Therefore, we conducted a literature review to obtain specific knowledge of this disease. Thirteen cases of VESS were found by searching the Medline and EMBASE databases in the English language. The mechanism of VESS may be associated with endometriosis, and its diagnosis largely depends on pathological examination because it has no typical symptoms. Treatment of VESS incorporates surgery, chemotherapy, radiotherapy, and hormonal therapy. Some novel drugs targeting its mechanism may become alternative therapies. Its prognostic factors may include tumor stage and the expression of hormonal receptors.

Comparative efficacy and safety of traditional Chinese patent medicine for endometriosis: A Bayesian network meta-analysis protocol

BACKGROUND

Endometriosis is a common disease of women of childbearing age. In recent years, the incidence of endometriosis has been on the rise. The main clinical manifestations are pelvic pain and infertility. In recent years, traditional Chinese patent medicine (TCMP) has played an important role in the treatment of endometriosis. So far, there is a lack of comparison among all the current common TCPMs for endometriosis. Consequently, it is indispensable to propose a network meta-analysis (NMA) protocol to discuss the strengths and weaknesses of different TCMPs.

METHODS

We will comprehensively and systematically retrieve the relevant Chinese and English databases from their inceptions to the May 2019. All randomized controlled trials (RCTs) of TCMPs for Endometriosis will be included. Two researchers will independently screen literature, extract data and assess the risk of bias of included studies. We will conduct pairwise meta-analyses and Bayesian network meta-analyses to assess all the available evidence. Data will be analyzed using STATA and WinBUGS software.

RESULTS

This work will compare and rank the relative efficacy of different TCPMs in the treatment of endometriosis in detail.

CONCLUSION

The results of this study will provide reliable evidence for the selection of clinical treatment program and guideline development.

PROSPERO REGISTRATION NUMBER

CRD42019127781.

A diagnosis of rheumatoid arthritis, endometriosis or IBD is associated with later onset of fibromyalgia and chronic widespread pain

BACKGROUND

Widespread pain is a common comorbidity in several chronic diseases and is suspected to be caused by pain resulting from the underlying disease that has provoked a state of central sensitization. However, this argument is currently limited by evidence that has insufficiently captured the temporal nature of the relationship between diagnosis of the underlying disease and onset of widespread pain. The aim of this study was to investigate if patients with rheumatoid arthritis (RA), endometriosis or inflammatory bowel disease (IBD), have a higher risk of developing widespread pain (fibromyalgia or chronic widespread pain [CWP]).

METHODS

Using the Swedish Skåne Healthcare register on health care consultation, a cohort of 889,938 adult patients were followed from 2007 to 2016 and incident cases of RA, endometriosis or IBD and of fibromyalgia and CWP were identified by registered diagnoses. Using Poisson regression, we calculated incidence rate ratios (IRR) adjusted for sex, age, education and propensity to seek health care.

RESULTS

For patients with RA the IRR for later fibromyalgia was 3.64 (95% CI: 2.75-4.81) compared to patients without RA, for CWP it was 2.96 (95% CI: 1.81-4.86). For endometriosis patients the IRR for fibromyalgia was 2.83 (95% CI: 1.96-4.08) and for CWP 5.02 (95% CI: 3.10-8.13). IBD patients had an IRR = 2.32 (95% CI: 1.58-3.42) for fibromyalgia and 1.42 (95% CI: 0.93-2.17) for CWP.

CONCLUSIONS

This study shows that RA, endometriosis and IBD are all risk factors for later fibromyalgia and CWP, consistent with a hypothesis of central sensitization as an effect of a painful underlying condition.

SIGNIFICANCE

We show that RA, endometriosis and IBD predisposes for later fibromyalgia and CWP, a common hypothesis previously difficult to verify due to lack of longitudinal data. The results inform further research regarding the aetiology of fibromyalgia and CWP and stress the need of clinical focus on the pain itself in chronic diseases with pain as a symptom.

Endometriosis-Associated Ovarian Cancer: Population Characteristics and Prognosis

OBJECTIVE

The aim of this study was to analyze and compare the clinicopathologic features and prognosis of clear cell ovarian carcinoma (CCOC) and endometrioid ovarian carcinoma (EOC) associated or not with endometriosis.

METHODS

This was a reconstituted cohort study from a single-institution Brazilian cancer center approved under review board no. 68150617.7.0000.5404 with 50 patients with CCOC and EOC diagnosed between 1995 and 2016, followed up until 2017. Clinicopathologic characteristics and survival outcomes were analyzed.

RESULT(S)

There were 23 women (46%) with CCOC and 27 with EOC (54%); 80% of those women had histologic confirmation of endometriosis; 42% were nulliparous, and 42% were premenopausal; and cancer antigen 125 was elevated in both International Federation of Gynecology and Obstetrics stages I-II disease (mean, 614.7 Ui/mL; range, 3-6030 Ui/mL) or International Federation of Gynecology and Obstetrics stages III-IV disease (mean, 2361.2 Ui/mL; range, 8-12771 Ui/mL). Women with EOC were 7 years younger than those with CCOC. When associated with endometriosis, CCOCs were more likely diagnosed at earlier stages. Endometrioid ovarian carcinoma and CCOC at initial stage and EOC at advanced stage share similar good prognosis. Univariate analysis showed that CCOC not associated with endometriosis has worse overall survival (OS). However, multivariate analysis showed that only abnormally elevated levels of cancer antigen 125 and advanced stage at diagnosis were significantly associated with reduced progression-free survival. Tumor stage remains the only prognostic factor for OS.

CONCLUSIONS

The presence of coexisting endometriosis did not change the prognosis of EOC but was associated with better OS in patients with CCOC. Patients with CCOC and EOC at initial stages and EOC at advanced stages have a good prognosis; however, CCOC at advanced stages had a sooner recurrence and shorter OS.

Atherosclerotic cardiovascular disease in women with endometriosis: a systematic review of risk factors and prospects for early surveillance

Endometriosis and atherosclerotic cardiovascular disease (ASCVD) share similar pathogenic mechanisms. Hence, this systematic review evaluates the association between endometriosis and lifetime ASCVD risk including co-prevalence with dyslipidaemia, atherosclerosis and non-invasive markers of endothelial dysfunction. The electronic databases Embase, PubMed, MEDLINE, Cochrane Register of Trials and ClinicalTrials.gov were systematically searched for relevant articles. Two prospective cohort studies demonstrated an increased lifetime ASCVD risk after controlling for demographic and lifestyle confounders in women with endometriosis, as measured by higher incidence of myocardial infarction (relative risk [RR] 1.52), angiography-confirmed angina (RR 1.91), or requiring coronary artery bypass graft surgery (RR 1.35). Among 10 studies that included 407 patients with surgically proven endometriosis and 557 controls, RR of developing hypercholesterolemia and hypertension were 1.25 and 1.14, respectively, while higher serum lipoprotein a and lower paraoxonase 1 levels were found in women with endometriosis that was negatively correlated with stage of disease (r = -0.74, P < 0.0001). Hence, currently available evidence suggests that women with endometriosis are at higher lifetime risk of developing ASCVD than women without endometriosis. However, robust causal evidence is still lacking and future studies are needed to determine whether women with endometriosis represent a high-risk population for lifelong ASCVD risk.

Elevated urine histone 4 levels in women with ovarian endometriosis revealed by discovery and parallel reaction monitoring proteomics

Endometriosis is a common gynecologic disorder and due to a lack of non-invasive detection methods, it can take up to 12 years before an affected woman obtains a diagnosis and receives appropriate treatment. Therefore, the identification of a specific biomarker that can be detected quickly and non-invasively is urgently needed. In this study, the urine proteome, a potentially rich source of biomarkers, is examined in patients with or without endometriosis in an attempt to identify novel protein biomarkers that can be used to diagnose endometriosis. This study is the first to combine tandem mass tags and parallel reaction monitoring approaches to aid in identifying and validating urine biomarkers for endometriosis. The findings presented herein support previous conclusions that endometriosis is a chronic inflammatory disease. Additionally, Histone 4 was identified as a potential biomarker and/or therapeutic target for endometriosis. At a cutoff of 14.2, the area under the curve for H4 was 0.848, with a sensitivity of 70% and specificity of 80%. Moreover, to our knowledge, this is the first study to observe an elevated histone level in body fluids obtained from endometriosis patients. While this study provides a good foundation, further studies are required to further validate the results presented. SIGNIFICANCE: Endometriosis is a common gynecologic disorder and due to a lack of non-invasive detection methods, it can take up to 12 years before an affected woman obtains a diagnosis and receives appropriate treatment. Therefore, the identification of a specific biomarker that can be detected quickly and non-invasively is urgently needed. We believe our results have an important impact on detection and treatment of endometriosis. Firstly, this study is the first to combine tandem mass tags and parallel reaction monitoring approaches to aid in identifying and validating urine biomarkers for endometriosis, which has established the methodology required for subsequent studies. Secondly, this is also the first study to observe an elevated histone level in body fluids obtained from endometriosis patients. Compared with other urine biomarkers reported in literature, histone 4 has a potential to serve as a biomarker of endometriosis and a therapeutic target. Thirdly, our study supports previous conclusions that endometriosis is a chronic inflammatory disease. These findings can warrant further investigation of the pathophysiology of endometriosis.

The Endobiota Study: Comparison of Vaginal, Cervical and Gut Microbiota Between Women with Stage 3/4 Endometriosis and Healthy Controls

Dysbiosis in the genital tract or gut microbiome can be associated with endometriosis. We sampled vaginal, cervical and gut microbiota from 14 women with histology proven stage 3/4 endometriosis and 14 healthy controls. The V3 and V4 regions of the 16S rRNA gene were amplified following the 16S Metagenomic Sequencing Library Preparation. Despite overall similar vaginal, cervical and intestinal microbiota composition between stage 3/4 endometriosis group and controls, we observed differences at genus level. The complete absence of Atopobium in the vaginal and cervical microbiota of the stage 3/4 endometriosis group was noteworthy. In the cervical microbiota, Gardnerella, Streptococcus, Escherichia, Shigella, and Ureoplasma, all of which contain potentially pathogenic species, were increased in stage 3/4 endometriosis. More women in the stage 3/4 endometriosis group had Shigella/Escherichia dominant stool microbiome. Further studies can clarify whether the association is causal, and whether dysbiosis leads to endometriosis or endometriosis leads to dysbiosis.