Increased peritoneal and endometrial gene expression of biologically relevant cytokines and growth factors during the menstrual phase in women with endometriosis

Exploring the link between dietary zinc intake and endometriosis risk: insights from a cross-sectional analysis of American women

BACKGROUND

Endometriosis is a complex disorder with genetic, immune, inflammatory, and multifactorial etiologies. Zinc, an essential trace element, plays a crucial role in various physiological processes. Dysregulation or deficiency of zinc can lead to aberrations in human physiology. However, the association between dietary zinc and endometriosis remains ambiguous. This study aimed to investigate the link between dietary zinc intake and endometriosis.

METHODS

Utilizing cross-sectional data from the National Health and Nutrition Examination Survey, we analyzed information from American women aged 20-54 years between 1999 and 2006. After adjusting for relevant covariates, multivariable logistic regression analysis was employed to assess correlations.

RESULTS

A total of 4315 women were included in the study. The multivariable logistic regression model revealed a positive correlation between dietary zinc intake and the risk of endometriosis, even after controlling for confounding variables. Relative to individuals with lower zinc consumption (≤ 8 mg/day), the adjusted odds ratio (OR) values for dietary zinc intake and endometriosis in the 8-14 mg/day and > 14 mg/day groups were 1.19 (95% CI: 0.92-1.54, p = 0.189) and 1.60 (95% CI: 1.12-2.27, p = 0.009), respectively.

CONCLUSIONS

Our findings suggest a positive correlation between dietary zinc intake and the prevalence of endometriosis. However, further investigations are necessary to better understand this association and explore the potential role of dietary zinc in endometriosis.

An integrated multi-tissue approach for endometriosis candidate biomarkers: a systematic review

Biomarker identification could help in deciphering endometriosis pathophysiology in addition to their use in the development of non invasive diagnostic and prognostic approaches, that are essential to greatly improve patient care. Despite extensive efforts, no single potential biomarker or combination has been clinically validated for endometriosis.Many studies have investigated endometriosis-associated biological markers in specific tissues, but an integrative approach across tissues is lacking. The aim of this review is to propose a comprehensive overview of identified biomarkers based on tissue or biological compartment, while taking into account endometriosis phenotypes (superficial, ovarian or deep, or rASRM stages), menstrual cycle phases, treatments and symptoms.We searched PubMed and Embase databases for articles matching the following criteria: 'endometriosis' present in the title and the associated term 'biomarkers' found as Medical Subject Headings (MeSH) terms or in all fields. We restricted to publications in English and on human populations. Relevant articles published between 01 January 2005 (when endometriosis phenotypes start to be described in papers) and 01 September 2022 were critically analysed and discussed.Four hundred forty seven articles on endometriosis biomarkers that included a control group without endometriosis and provided specific information on endometriosis phenotypes are included in this review. Presence of information or adjustment controlling for menstrual cycle phase, symptoms and treatments is highlighted, and the results are further summarized by biological compartment. The 9 biological compartments studied for endometriosis biomarker research are in order of frequency: peripheral blood, eutopic endometrium, peritoneal fluid, ovaries, urine, menstrual blood, saliva, feces and cervical mucus. Adjustments of results on disease phenotypes, cycle phases, treatments and symptoms are present in 70%, 29%, 3% and 6% of selected articles, respectively. A total of 1107 biomarkers were identified in these biological compartments. Of these, 74 were found in several biological compartments by at least two independent research teams and only 4 (TNF-a, MMP-9, TIMP-1 and miR-451) are detected in at least 3 tissues with cohorts of 30 women or more.Integrative analysis is a crucial step to highlight potential pitfalls behind the lack of success in the search for clinically relevant endometriosis biomarkers, and to illuminate the physiopathology of this disease.

Association of endometriosis with Sjögren's syndrome: Genetic insights (Review)

Patients with a history of endometriosis have an increased risk of developing various autoimmune diseases such as rheumatoid arthritis, ankylosing spondylitis, systemic lupus erythematosus, multiple sclerosis and celiac disease. There is a potential association between endometriosis and an increased susceptibility for Sjögren's syndrome (SS). SS is a common chronic, inflammatory, systemic, autoimmune, multifactorial disease of complex pathology, with genetic, epigenetic and environmental factors contributing to the development of this condition. It occurs in 0.5‑1% of the population, is characterized by the presence of ocular dryness, lymphocytic infiltrations and contributes to neurological, gastrointestinal, vascular and dermatological manifestations. Endometriosis is an inflammatory, estrogen‑dependent, multifactorial, heterogeneous gynecological disease, affecting ≤10% of reproductive‑age women. It is characterized by the occurrence of endometrial tissue outside the uterine cavity, mainly in the pelvic cavity, and is associated with pelvic pain, dysmenorrhea, deep dyspareunia and either subfertility or infertility. It is still unclear whether SS appears as a secondary response to endometriosis, or it is developed due to any potential shared mechanisms of these conditions. The aim of the present review was to explore further the biological basis only of the co‑occurrence of these disorders but not their association at clinical basis, focusing on the analysis of the partially shared genetic background between endometriosis and SS, and the clarification of the possible similarities in the underlying pathogenetic mechanisms and the relevant molecular pathways.

Menstrual cycle abnormalities in women with inflammatory bowel disease and effects of biological therapy on gynecological pathology

Inflammatory bowel disease (IBD) is a chronic condition that affects young individuals in their reproductive years. It may have long-term implications on their reproductive, sexual, and mental health. IBD has been related to menstrual abnormalities. Furthermore, the administration of biological therapy can also result in gynecological issues in addition to the disease itself. The purpose of this review was to present potential menstrual cycle problems in patients with IBD, as well as the impact of adalimumab and other anti-tumor necrosis factor medications on gynecological pathology.

Does the Use of the "Proseek® Multiplex Inflammation I Panel" Demonstrate a Difference in Local and Systemic Immune Responses in Endometriosis Patients with or without Deep-Infiltrating Lesions?

Endometriotic lesions are able to infiltrate surrounding tissue. This is made possible partly by an altered local and systemic immune response that helps achieve neoangiogenesis, cell proliferation and immune escape. Deep-infiltrating endometriosis (DIE) differs from other subtypes through the invasion of its lesions over 5 mm into affected tissue. Despite the invasive nature of these lesions and the wider range of symptoms they can trigger, DIE is described as a stable disease. This elicits the need for a better understanding of the underlying pathogenesis. We used the "Proseek^® Multiplex Inflammation I Panel" in order to simultaneously detect 92 inflammatory proteins in plasma and peritoneal fluid (PF) of controls and patients with endometriosis, as well as in particular patients with DIE, in order to gain a better insight into the systemically and locally involved immune response. Extracellular newly identified receptor for advanced gycation end-products binding protein (EN-RAGE), C-C motif Chemokine ligand 23 (CCL23), Eukaryotic translation initiation factor 4-binding protein 1 (4E-BP1) and human glial cell-line derived neurotrophic factor (hGDNF) were significantly increased in plasma of endometriosis patients compared to controls, whereas Hepatocyte Growth factor (HGF) and TNF-related apoptosis inducing ligand (TRAIL) were decreased. In PF of endometriosis patients, we found Interleukin 18 (IL-18) to be decreased, yet Interleukin 8 (IL-8) and Interleukin 6 (IL-6) to be increased. TNF-related activation-induced cytokine (TRANCE) and C-C motif Chemokine ligand 11 (CCL11) were significantly decreased in plasma, whereas C-C motif Chemokine ligand 23 (CCL23), Stem Cell Factor (SCF) and C-X-C motif chemokine 5 (CXCL5) were significantly increased in PF of patients with DIE compared to endometriosis patients without DIE. Although DIE lesions are characterized by increased angiogenetic and pro-inflammatory properties, our current study seems to support the theory that the systemic immune system does not play a major role in the pathogenesis of these lesions.

A cross-sectional study comparing the inflammatory profile of menstrual effluent vs. peripheral blood

Background and Aims

Cytokine profiles of peripheral blood and other bodily fluids provide diagnostic indicators for assessing inflammatory processes. Menstrual effluent may provide a noninvasive source of biological material for monitoring cytokine levels in blood and in endometrial tissues. This pilot study investigated the potential of measuring cytokines in menstrual effluent, and compared the cytokine profiles of menstrual versus peripheral blood.

Methods

Seven healthy donors (aged ≥18 and ≤45 years) collected menstrual effluent on day 2 of menses. Matched peripheral blood samples were collected by venous blood draw on the same day. Levels of 62 cytokines were measured in all samples by 62-plex Luminex assay.

Results

Peripheral blood and menstrual effluent cytokine profiles were tenuously correlated (r 2 = 0.26, p < 0.0001), with higher levels detected in menstrual effluent for 48/62 cytokines. Thirty five cytokines were significantly elevated in menstrual effluent compared to peripheral blood samples (IL-8, CCL2, CCL4, LIF, IL-1RA, IL-6, IL-1β, HGF, CCL3, FGF-2, TNF-α, VEGF-A, IL-1α, CXCL1, IL-9, IL-10, EGF, CXCL5, CSF3, EOTAXIN, TGF-α, TRAIL, CXCL10, VEGF-D, IL-12P40, CXCL9, IL-18 RESISTIN, IL-22, IL-21, CSF1, IFN-γ, IL-17A, CXCL12, IL-12p70). Two cytokines (LEPTIN, CSF2) were expressed at significantly lower levels in menstrual effluent compared to peripheral blood. Linear regression of individual cytokines found low predictive power (linear regression p > 0.05) for 53/62 cytokines in menstrual effluent versus peripheral blood. Levels of TGF-β (r 2 = 0.87, p = 0.002) and CCL7 (r 2 = 0.63, p = 0.033) were significantly positively correlated between matched menstrual and peripheral blood samples.

Conclusion

In this group of study participants, the cytokine profile of menstrual effluent was quantitatively distinct from peripheral blood, and also characterized by higher levels of inflammatory signaling. This pattern of comparative menstrual blood cytokine profiles points to a need for further studies to evaluate the relationship between peripheral and menstrual blood cytokines in broader populations including both healthy and diseased states.

12-O-Tetradecanoylphorbol 13-acetate promotes proliferation and epithelial-mesenchymal transition in HHUA cells cultured on collagen type I gel: A feasible model to find new therapies for endometrial diseases

HHUA endometrial adenocarcinoma cells aggregated into spheroids when cultured on collagen type I gels. 12-O-Tetradecanoylphorbol 13-acetate, a PKC activator, disassembled the spheroids through epithelial-mesenchymal transition and increased their proliferation rate, while inducing cell death under monolayer culture conditions. These unusual behaviors of endometrial epithelial cells with collagen fibers could be a target for the treatment of some endometrial diseases.

Integrated bioinformatic analysis of dysregulated microRNA-mRNA co-expression network in ovarian endometriosis

INTRODUCTION

Ovarian endometriosis is a frequently occurring gynecological disease with large socioeconomic impact. Accumulating evidence has suggested that aberrant miRNA-mRNA interactions are involved in the pathogenesis and progression of ovarian endometriosis. This study aims to identify key miRNAs in ovarian endometriosis by using integrated bioinformatic analysis of a dysregulated miRNA-mRNA co-expression network.

MATERIAL AND METHODS

Expression profiling of miRNA and mRNA in three normal endometria and five pairs of ectopic/eutopic endometria from patients with ovarian endometriosis was determined by high-throughput sequencing techniques. The data were then integrated with the public sequencing datasets (GSE105764 and GSE105765) using a non-biased approach and a miRNA-mRNA co-expression regulatory network was constructed by in-depth bioinformatic analysis.

RESULTS

The constructed miRNA-mRNA network included 87 functionally DEMs, 482 target mRNAs and 1850 paired miRNA-mRNA regulatory interactions. Specifically, five miRNAs (miR-141-3p, miR-363-3p, miR-577, miR-767-5p, miR-96-5p) were gradually decreased and two miRNAs (miR-493-5p, miR-592) were gradually increased from normal endometria to eutopic endometria, and then ectopic endometria tissues. Importantly, miR-141-3p, miR-363-3p and miR-96-5p belonged to the miR-200 family, miR-106a-363 cluster and miR-183/96/182 cluster, respectively. Their target mRNAs were mainly associated with cell adhesion, locomotion and binding, which are suggested to play vital regulatory roles in the pathogenesis of ovarian endometriosis.

CONCLUSIONS

Integrated bioinformatic analysis of the miRNA-mRNA co-expression network defines the crucial roles of the miR-200 family, miR-106a-363 cluster and miR-183/96/182 cluster in the pathogenesis of ovarian endometriosis. Further in-depth functional studies are needed to unveil the molecular mechanisms of these miRNAs, and may provide clues for the optimization of therapeutic strategies for ovarian endometriosis.

The role of extracellular matrix on unfavorable maternal–fetal interface: focusing on the function of collagen in human fertility

Extracellular matrix (ECM) is characterized as widespread, abundant, and pluripotent. Among ECM members, collagen is widely accepted as one of the most prominent components for its essential structural property that can provide a scaffold for other components of ECM and the rich biological functions, which has been extensively used in tissue engineering. Emerging evidence has shown that the balance of ECM degradation and remodeling is vital to regulations of maternal–fetal interface including menstrual cycling, decidualization, embryo implantation and pregnancy maintenance. Moreover, disorders in these events may eventually lead to failure of pregnancy. Although the improvement of assisted conception and embryo culture technologies bring hope to many infertile couples, some unfavorable outcomes, such as recurrent implantation failure (RIF), recurrent pregnancy loss (RPL) or recurrent miscarriage (RM), keep troubling the clinicians and patients. Recently, in vitro three-dimensional (3D) model mimicking the microenvironment of the maternal–fetal interface is developed to investigate the physiological and pathological conditions of conception and pregnancy. The progress of this technology is based on clarifying the role of ECM in the endometrium and the interaction between endometrium and conceptus. Focusing on collagen, the present review summarized the degradation and regulation of ECM and its role in normal menstruation, endometrium receptivity and unsatisfying events occurring in infertility treatments, as well as the application in therapeutic approaches to improve pregnancy outcomes. More investigations about ECM focusing on the maternal–fetal interface interaction with mesenchymal stem cells or local immunoregulation may inspire new thoughts and advancements in the clinical application of infertility treatments.

Graphical abstract

Evaluating the effect of conditioned medium from endometrial stem cells on endometriosis-derived endometrial stem cells

Endometriosis is a common, benign gynecological disease which is determined as an overspreading of endometrial tissue in exterior region of the uterine cavity. Evidence suggests that retrograde menstrual blood which contains mesenchymal stem cells with differential gene expression compared to healthy women may play a role in endometriosis creation. We aimed to identify whether the conditioned medium (CM) from menstrual blood-derived mesenchymal stem cells (MenSCs) of healthy women can affect the expression level of inflammatory and stemness genes of MenSCs from endometriosis women. Endometriosis-derived MenSCs (E-MenSCs) were treated with CM derived from healthy women’s MenSCs (non-endometriosis derived MenSCs [NE-MenSCs]). Some CD markers were analyzed by flow cytometer before and after treatment compared with NE-MenSCs, and the expression level of inflammatory and stemness genes was evaluated by real-time PCR. E-MenSCs show different morphology in vitro culture in comparison with NE-MenSCs, which were changed in the presence of CM, into a morphology more similar to normal cells and showed significant decrease expression of CD10 after CM treatment. In our results, the interleukin-1, cyclooxygenase-2, and hypoxia-inducible factor 1α as inflamaturay genes and octamer-binding transcription factor 4, NANOG, and sex determining region Y-box 2 as stemness genes showed significantly different expression level in E-MenSCs after treating with CM. Our study indicates that the expression level of some inflammatory- and stemness-related genes which have differential expression in E-MenSCs compared with NE-MenSCs, could be changed to normal status by using CM derived from NE-MenSCs.

Menstruation Dysregulation and Endometriosis Development

Endometriosis is a common gynecological condition characterized by the growth of endometrial-like tissue outside of the uterus which may cause symptoms such as chronic pelvic pain or subfertility. Several surgical and medical therapies are available to manage symptoms, but a cure has yet to be determined which can be attributed to the incomplete understanding of disease pathogenesis. Sampson's theory of retrograde menstruation is a widely accepted theory describing how shed endometrial tissue can enter the peritoneal cavity, but other factors are likely at play to facilitate the establishment of endometriosis lesions. This review summarizes literature that has explored how dysregulation of menstruation can contribute to the pathogenesis of endometriosis such as dysregulation of inflammatory mediators, aberrant endometrial matrix metalloproteinase expression, hypoxic stress, and reduced apoptosis. Overall, many of these factors have overlapping pathways which can prolong the survival of shed endometrial debris, increase tissue migration, and facilitate implantation of endometrial tissue at ectopic sites. Moreover, some of these changes are also implicated in abnormal uterine bleeding and endometrial diseases. More research is needed to better understand the underlying mechanisms driving dysregulation of menstruation in endometriosis specifically and identifying specific pathways could introduce new treatment targets. Analyzing menstrual fluid from women with endometriosis for inflammatory markers and other biomarkers may also be beneficial for earlier diagnosis and disease staging.

Epithelial-to-mesenchymal transition contributes to the downregulation of progesterone receptor expression in endometriosis lesions

Endometriosis is a common, estrogen-dependent disease, in which endometrial tissue grows in the peritoneal cavity. These lesions often express low levels of progesterone receptors (PR), which potentially play an important role in the insufficient response to progestin treatment. Here, we uncover an interconnection between the downregulated PR expression and the epithelial-to-mesenchymal transition (EMT) in endometriotic lesions. The majority of ectopic epithelial glands (93.1 %, n = 67/72) display heterogeneous states of EMT by immunohistochemistry staining. Interestingly, low PR expression associated with high N-cadherin expression, a hallmark of EMT. In order to gain mechanistic insights, we performed in vitro functional assays with the endometriotic epithelial cell lines EM'osis and 12Z. TGF-β-induced EMT, marked by elevations of CDH2 and SNAI1/2, led to a significant downregulation of PR gene expression in both cell lines. In contrast, silencing of SNAI1 in EM'osis and of SNAI1 plus SNAI2 in 12Z elevated PR gene expression significantly. We found that not only in vitro, but also in the epithelial component of endometriotic lesions strong expression of SNAI1/2 concurred with weak expression of PR. In summary, these results suggested the negative correlation association of the heterogeneous states of EMT and suppressed PR expression in endometriotic lesions. Our functional assays indicate that EMT contributes to the downregulation of PR expression via the upregulation of EMT-TFs, like SNAI1 and SNAI2, which may ultimately lead to progesterone resistance.

Overexpressed MPS-1 contributes to endometrioma development through the NF-κB signaling pathway

BACKGROUND

Endometriosis is a benign gynecological disease that shares some characteristics with malignant tumors and affects approximately 10% of women of reproductive age. Endometrioma refers to endometriosis that appears in the ovary. Metallopanstimulin-1 (MPS-1) is a component of the 40S subunit of ribosomes that has extra-ribosomal functions that contribute to the development of diseases. This study aimed to explore the expression pattern and role of MPS-1 in endometrioma development.

METHODS

Quantitative real time polymerase chain reaction, western blotting, immunohistochemistry, and enzyme-linked immunosorbent assay were used to determine the expression of MPS-1 in patients with endometrioma. Following the successful knockdown of MPS-1 by siRNA, CCK-8 assays, flow cytometry, and transwell assays were performed to detect ectopic endometrial stromal cells (EcESCs) proliferation, the rate of apoptosis, and cell cycle, migration, and invasion, respectively. Western blotting was used to explore the effect of MPS-1 knockdown on protein levels in the NF-κB signaling pathway.

RESULTS

The expression of MPS-1 was significantly higher in endometrioma and the serum of endometrioma patients than in the patients without endometriosis. In addition, the downregulation of MPS-1 expression inhibited EcESCs proliferation, migration, and invasion. This downregulation led to the arrest of the EcESCs cycle in the G0/G1 phase and apoptosis and depressed the NF-κB signaling pathway.

CONCLUSION

MPS-1 can regulate EcESCs proliferation, motility, invasion, apoptosis, and cell cycle via the NF-κB signaling pathway in endometrioma. This may contribute to the formation or development of endometriotic foci. This study suggests the potential role of MPS-1 in the pathogenesis of endometriosis and enabled further research into the use of MPS-1 in the clinical diagnosis of endometrioma.

Mesothelial Cells Participate in Endometriosis Fibrogenesis Through Platelet-Induced Mesothelial-Mesenchymal Transition

CONTEXT

While fibrosis in endometriosis has recently loomed prominently, the sources of myofibroblasts, the principal effector cell in fibrotic diseases, remain largely obscure. Mesothelial cells (MCs) can be converted into myofibroblasts through mesothelial-mesenchymal transition (MMT) in many fibrotic diseases and adhesion.

OBJECTIVE

To evaluate whether MCs contribute to the progression and fibrogenesis in endometriosis through MMT.

SETTING, DESIGN, PATIENTS, INTERVENTION, AND MAIN OUTCOME MEASURES

Dual immunofluorescence staining and immunohistochemistry using antibodies against calretinin, Wilms' tumor-1 (WT-1), and α-smooth muscle actin (α-SMA) were performed on lesion samples from 30 patients each with ovarian endometrioma (OE) and deep endometriosis (DE), and 30 normal endometrial (NE) tissue samples. Human pleural and peritoneal MCs were co-cultured with activated platelets or control medium with and without neutralization of transforming growth factor β1 (TGF-β1) and/or platelet-derived growth factor receptor (PDGFR) and their morphology, proliferation, and expression levels of genes and proteins known to be involved in MMT were evaluated, along with their migratory and invasive propensity, contractility, and collagen production.

RESULTS

The number of calretinin/WT-1 and α-SMA dual-positive fibroblasts in OE/DE lesions was significantly higher than NE samples. The extent of lesional fibrosis correlated positively with the lesional α-SMA staining levels. Human MCs co-cultured with activated platelets acquire a morphology suggestive of MMT, concomitant with increased proliferation, loss of calretinin expression, and marked increase in expression of mesenchymal markers. These changes coincided with functional differentiation as reflected by increased migratory and invasive capacity, contractility, and collagen production. Neutralization of TGF-β1 and PDGFR signaling abolished platelet-induced MMT in MCs.

CONCLUSIONS

MCs contribute to lesional progression and fibrosis through platelet-induced MMT.

Menstrual Effluent Provides a Novel Diagnostic Window on the Pathogenesis of Endometriosis

Endometriosis is a chronic inflammatory disorder characterized by the presence of endometrial-like tissue growing outside of the uterus. Although the cause is unknown, retrograde menstruation leads to deposition of endometrial cells into the peritoneal cavity. Lack of disease recognition and long diagnostic delays (6–10 years) lead to substantial personal, social and financial burdens, as well as delayed treatment. A non-invasive diagnostic for endometriosis is a major unmet clinical need. Here, we assessed whether differences in menstrual effluent-derived stromal fibroblast cells (ME-SFCs) from women with and without endometriosis provide the basis for a non-invasive diagnostic for endometriosis. In addition, we investigated whether treatment of control ME-SFCs with inflammatory cytokines (TNF and IL-1β) could induce an endometriosis-like phenotype. ME-SFCs from laparoscopically diagnosed endometriosis patients exhibit reduced decidualization capacity, measured by IGFBP1 production after exposure to cAMP. A receiver operating characteristic (ROC) curve developed using decidualization data from controls and endometriosis subjects yielded an area under the curve of 0.92. In addition, a significant reduction in ALDH1A1 gene expression and increased podoplanin surface expression were also observed in endometriosis ME-SFCs when compared to control ME-SFCs. These endometriosis-like phenotypes can be reproduced in control ME-SFCs by exposure to inflammatory cytokines (TNF and IL-1β) and are associated with increased cell migration. These results are consistent with the hypothesis that chronic intrauterine inflammation influences the development of endometriosis lesions following retrograde menstruation. In conclusion, the analysis of ME-SFCs can provide an accurate, rapid, and non-invasive diagnostic for endometriosis and insight into disease pathogenesis.

Does the Use of the "Proseek® Multiplex Oncology I Panel" on Peritoneal Fluid Allow a Better Insight in the Pathophysiology of Endometriosis, and in Particular Deep-Infiltrating Endometriosis?

Endometriosis appears to share certain cancer-related processes, such as cell attachment, invasion, proliferation and neovascularization, some of which can also be found in other healthy tissues. In order to better understand the altered milieu of the peritoneal cavity, while acknowledging the reported similarities between endometriosis and neoplastic processes, we applied a multiplex oncology panel to search for specific biomarker signatures in the peritoneal fluid of women with endometriosis, women with deep-infiltrating endometriosis (DIE), as well as controls. In total, 84 patients were included in our study, 53 women with endometriosis and 31 controls. Ninety-two proteins were measured in prospectively collected peritoneal fluid (PF) samples, using the "Proseek® Multiplex Oncology I Panel". We first compared patients with endometriosis versus controls, and in a second step, DIE versus endometriosis patients without DIE. Out of the 92 analyzed proteins, few showed significant differences between the groups. In patients with endometriosis, ICOS ligand, Endothelial growth factor, E-selectin, Receptor tyrosine-protein kinase erbB-2, Interleukin-6 receptor alpha, Vascular endothelial growth factor receptor 2, Fms-related tyrosine kinase 3 ligand, C-X-C motif chemokine 10, Epididymal secretory protein E4 and Folate receptor-alpha were decreased, while Interleukin-6 and Interleukin-8 were increased compared to controls. Looking at patients with DIE, we found Chemokine ligand 19, Stem cell factor, Vascular endothelial growth factor D, Interleukin-6 receptor alpha and Melanoma inhibitory activity to be increased compared to endometriosis patients without DIE. We have shown a distinct regulation of the immune response, angiogenesis, cell proliferation, cell adhesion and inhibition of apoptosis in PF of patients with endometriosis compared to controls. The specific protein pattern in the PF of DIE patients provides new evidence that DIE represents a unique entity of extrauterine endometriosis with enhanced angiogenetic and pro-proliferative features.

Peritoneal Fluid Cytokines Reveal New Insights of Endometriosis Subphenotypes

Endometriosis is a common inflammatory gynecological disorder which causes pelvic scarring, pain, and infertility, characterized by the implantation of endometrial-like lesions outside the uterus. The peritoneum, ovaries, and deep soft tissues are the commonly involved sites, and endometriotic lesions can be classified into three subphenotypes: superficial peritoneal endometriosis (PE), ovarian endometrioma (OE), and deep infiltrating endometriosis (DIE). In 132 women diagnosed laparoscopically with and without endometriosis (n = 73, 59 respectively), and stratified into PE, OE, and DIE, peritoneal fluids (PF) were characterized for 48 cytokines by using multiplex immunoassays. Partial-least-squares-regression analysis revealed distinct subphenotype cytokine signatures—a six-cytokine signature distinguishing PE from OE, a seven-cytokine signature distinguishing OE from DIE, and a six-cytokine-signature distinguishing PE from DIE—each associated with different patterns of biological processes, signaling events, and immunology. These signatures describe endometriosis better than disease stages (p < 0.0001). Pathway analysis revealed the association of ERK1 and 2, AKT, MAPK, and STAT4 linked to angiogenesis, cell proliferation, migration, and inflammation in the subphenotypes. These data shed new insights on the pathophysiology of endometriosis subphenotypes, with the potential to exploit the cytokine signatures to stratify endometriosis patients for targeted therapies and biomarker discovery.

Expression of Matrix Metalloproteinases and Their Inhibitors in Endometrium: High Levels in Endometriotic Lesions

Endometriosis is a condition defined as presence of endometrium outside of the uterine cavity. These endometrial cells are able to attach and invade the peritoneum or ovary, thus forming respectively the deep infiltrating endometriosis (DIE) and the ovarian endometrioma (OMA), the ectopic lesions feature of this pathology. Endometriotic cells display high invasiveness and share some features of malignancy with cancer cells. Indeed, the tissue remodeling underlining lesion formation is achieved by matrix metalloproteinases (MMPs) and their inhibitors. Therefore, these molecules are believed to play a key role in development and pathogenesis of endometriosis. This study investigated the molecular profile of metalloproteinases and their inhibitors in healthy (n = 15) and eutopic endometrium (n = 19) in OMA (n = 10) and DIE (n = 9); moreover, we firstly validated the most reliable housekeeping genes allowing accurate gene expression analysis in these tissues. Gene expression, Western blot, and immunofluorescence analysis of MMP2, MMP3, and MMP10 and their tissue inhibitors TIMP1 and TIMP2 demonstrated that these enzymes are finely tuned in these tissues. In OMA lesions, all the investigated MMPs and their inhibitors were significantly increased, while DIE expressed high levels of MMP3. Finally, in vitro TNFα treatment induced a significant upregulation of MMP3, MMP10, and TIMP2 in both healthy and eutopic endometrial stromal cells. This study, shedding light on MMP and TIMP expression in endometriosis, confirms that these molecules are altered both in eutopic endometrium and endometriotic lesions. Although further studies are needed, these data may help in understanding the molecular mechanisms involved in the extracellular matrix remodeling, a crucial process for the endometrial physiology.

Endometrial stromal cells treated by tumor necrosis factor-α stimulate macrophages polarized toward M2 via interleukin-6 and monocyte chemoattractant protein-1

AIM

This study aimed to investigate the effects of endometrial stromal cells (ESC)-derived interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1 on macrophage polarization in endometriosis.

METHODS

Macrophage polarization was measured in eutopic endometrium of control participants ('normal endometrium'), eutopic endometrium of patients with endometriosis ('eutopic endometrium') and ectopic endometrium of endometriosis patients ('ectopic endometrium') by immunohistochemical staining. Expression of IL-6 and MCP-1 were measured in the eutopic and ectopic endometrium through enzyme-linked immunosorbent assays. Expression of CD163 was measured in human acute monocytic leukemia (THP-1) cell-derived macrophages that were treated with conditional medium induced by tumor necrosis factor (TNF)-α, TNF-α + anti-IL-6 or TNF-α + anti-MCP-1 via flow cytometry.

RESULTS

The ratio of CD163+/CD68+ macrophages in the normal endometrium was higher than that in the eutopic endometrium, while differences between the eutopic and ectopic endometrium were not statistically significant. IL-6 and MCP-1 exhibited enhanced expression in the ectopic endometrium group and decreased expression in the eutopic endometrium group. TNF-α could promote the expression of ESC-derived IL-6 and MCP-1. Intervention with TNF-α-induced conditioned medium resulted in the upregulation of CD163 in THP-1 cells, while conditional medium induced with IL-6 and MCP-1 neutralizing antibodies decreased the proportion of CD163+ macrophages significantly.

CONCLUSION

In endometriosis patients, the macrophages of the eutopic endometrium polarize toward M1 compared with the normal endometrium, and those of the ectopic endometrium were mainly M2-polarized. Under the action of TNF-α, ESC-derived IL-6 and MCP-1 could stimulate peritoneal macrophages toward M2-polarization, which could modulate endometriosis.

Endometrial biopsy and density of nerve fibers in eutopic endometrium. Looking for easier ways to diagnose endometriosis

The purpose of study was to evaluate if there is any difference between nerve fibers density in eutopic endometrium in women with and without endometriosis. The prospective case - control study conducted between October 2013 and December 2015. The study included 60 reproductive age women undergoing laparoscopy for suspected endometriosis, pelvic pain, or infertility and not currently receiving hormonal treatment for at least 3 months prior to laparoscopy. Immunohistochemical nerve fiber detection in endometrial curetting using anti-gene product 9.5 was compared with surgical diagnosis. The nerve fibers were detected in eutopic endometrium in women with and without endometriosis. PGP9.5 positive nerve fibers were found in 26 (43%) cases: 16 (50%) in women with endometriosis and 10 (36%) in women without endometriosis. The mean nerve fiber density was higher in the group with endometriosis (0.53 per mm² ± 0.68) than without endometriosis (0.48 per mm² ± 0.89), but no statistically significant difference was observed (p > .05). Test specificity was 64.3%, sensitivity 50%, positive predictive value - 61.5%, negative predictive value - 52.9%, and overall accuracy 56.7%. The detection of PGP9.5 positive nerve fibers in eutopic endometrium cannot be used as a reliable diagnostic test of diagnosing endometriosis.

Effect of Central Injection of Neostigmine on the Bacterial Endotoxin Induced Suppression of GnRH/LH Secretion in Ewes during the Follicular Phase of the Estrous Cycle

Induced by a bacterial infection, an immune/inflammatory challenge is a potent negative regulator of the reproduction process in females. The reduction of the synthesis of pro-inflammatory cytokine is considered as an effective strategy in the treatment of inflammatory induced neuroendocrine disorders. Therefore, the effect of direct administration of acetylcholinesterase inhibitor—neostigmine—into the third ventricle of the brain on the gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretions under basal and immune stress conditions was evaluated in this study. In the study, 24 adult, 2-years-old Blackhead ewes during the follicular phase of their estrous cycle were used. Immune stress was induced by the intravenous injection of LPS Escherichia coli in a dose of 400 ng/kg. Animals received an intracerebroventricular injection of neostigmine (1 mg/animal) 0.5 h before LPS/saline treatment. It was shown that central administration of neostigmine might prevent the inflammatory-dependent decrease of GnRH/LH secretion in ewes and it had a stimulatory effect on LH release. This central action of neostigmine is connected with its inhibitory action on local pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)α synthesis in the hypothalamus, which indicates the importance of this mediator in the inhibition of GnRH secretion during acute inflammation.

Possible Role of the Posterior Compartment Peritonectomy, as a Part of the Complex Surgery, Regarding Recurrence Rate, Improvement of Symptoms and Fertility Rate in Patients with Endometriosis, Long-Term Follow-Up

STUDY OBJECTIVE

Beside the pain, there are 2 further problems in the management of endometriosis: the high recurrence rate (10% per year) and the high rate of impaired fertility. The objective of this study was to investigate the pathogenesis of these 2 factors.

DESIGN

This is a retrospective cohort study, and the aim is to evaluate the complete excision of endometriotic lesions, including the posterior compartment of the peritoneum, with regard to postoperative outcome, focusing on relieving pain, increasing fertility rate, and decreasing recurrence rate.

SETTING

Charité-University Clinic, Department of Gynaecology, Endometriosis research Centre.

PATIENTS

Fifty-four patients were enrolled in this study, with severe deep infiltrating endometriosis (scored by ENZIAN) and superficial endometriosis, as well as endometriomas (revised American Society for Reproductive Medicine [rASRM] I = 3; II = 15; III = 10; and IV = 26).

INTERVENTIONS

Posterior compartment peritonectomy (visible endometriotic lesions and inflamed altered peritoneum) was performed in all patients as part of a complex surgery: complete excision of endometriosis.

MEASUREMENTS AND MAIN RESULTS

Postoperative outcomes were evaluated, based on the postoperative follow-up (up to 5 years) of 54 investigated patients. In 36 women (66%) preoperative complaints were eliminated. Furthermore, of 28 women seeking improved fertility, pregnancy was reported in 13 cases (46%). In 7 (54%) cases pregnancy occurred spontaneously, and in the remainder with assisted fertilization. In addition, long-term follow-up demonstrated a recurrence rate in 1.8% of patients.

CONCLUSION

Overall, the number of complaints was significantly reduced. Only in the case of reproductive-aged women with ongoing postoperative complaints was it important to preserve the uterus. Although this pilot study on systematic posterior peritonectomy showed improvement in recurrence and fertility rate, the main question remains: will this surgical technique achieve better results and outcomes in the future? This has to be addressed in a prospective randomized study.

Overexpression of TGF-β enhances the migration and invasive ability of ectopic endometrial cells via ERK/MAPK signaling pathway

Endometriosis is a common gynecological disease with manifestations of endometrial-like tissue outside the uterus. Transforming growth factor-β (TGF-β) is known to facilitate a series of biological events in many cells, including migration. However, the roles of TGF-β in endometriosis still remain largely unknown. The aim of the present study was to discover the role of TGF-β1 in endometriosis development and progression and its associated mechanisms. It was demonstrated that the expression of TGF-β1 was significantly elevated in endometriosis in comparison with that in normal tissue. Overexpression of TGF-β increased the proliferation and upregulated proliferating cell nuclear antigen and cyclin D1 in endometrial stromal cells (ESCs). Furthermore, TGF-β overexpression also triggered a series of biological events occurring in ESCs, including cell migration and invasion, and activated the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) signaling pathway. The inhibition of the ERK/MAPK pathway reversed the previous effects of TGF-β overexpression. Collectively, the present results indicate that overexpression of TGF-β enhances the migration and invasion of ectopic ESCs via the ERK/MAPK signaling pathway, providing theoretical evidence for the development of new treatment methods targeting the TGF-β-ERK/MAPK signaling pathway for prophylaxis of endometriosis.

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

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

Lipophilic statins inhibit growth and reduce invasiveness of human endometrial stromal cells

PURPOSE

To compare effects of lipid-soluble statins (simvastatin, lovastatin, atorvastatin) and water-soluble statin (pravastatin) on growth and invasiveness of human endometrial stromal (HES) cells.

METHODS

Endometrial biopsies were collected during the proliferative phase from five volunteers. HES cells were isolated and cultured in the absence or in the presence of simvastatin, lovastatin, atorvastatin, and pravastatin. Effects of statins on DNA synthesis, cell viability, activity of caspases 3/7 and invasiveness were evaluated.

RESULTS

The proliferation of HES cells was significantly decreased by simvastatin (by 47-89%), lovastatin (by 46-78%), and atorvastatin (by 21-48%) in a concentration-dependent manner. Activity of executioner caspases 3/7 was significantly increased by simvastatin (by 10-25%), lovastatin (by 19%) and atorvastatin (by 7-10%) in a concentration-dependent manner. The greatest effects were observed in response to simvastatin. Accounting for the effects of statins on cell number, the invasiveness of HES cells was significantly decreased in cells treated with simvastatin (by 49%), lovastatin (by 54%), and atorvastatin (by 53%). Pravastatin had little or no effects on any of the tested endpoints.

CONCLUSIONS

Present findings demonstrate that only lipid-soluble among tested statins were effective in inhibition of growth and invasiveness of HES cells. These findings may have clinical relevance in treatment of endometriosis.

Epithelial-to-mesenchymal transition in the development of endometriosis

Endometriosis, an estrogen-dependent chronic gynecological disease, is common in reproductive-age women and profoundly affects their life quality. Although various pathogenic theories have been proposed, the origin of endometriosis remains unclear. Epithelial to mesenchymal transition (EMT) is a process that epithelial cells lose polarized organization of the cytoskeleton and cell-to-cell contacts, acquiring the high motility of mesenchymal cells. These changes are thought to be prerequisites for the original establishment of endometriotic lesions. However, no study exactly indicates which type of EMT occurs in endometriosis. In this review, we conclude that two different types of EMT may participate in this disease. Besides, two stimulating signals, hypoxia and estrogen, can through different pathways to activate the EMT process in endometriosis. Those pathways involve many cellular factors such as TGF-beta and Wnt, ultimately leading to cell proliferation and migration. As infertility is becoming a serious and intractable issue for women, EMT, during the implantation process, is gaining attention. In this review, we will describe the known functions of EMT in endometriosis, and suggest further studies that may aid in the development of medical therapy.

Decreased Expression of HOXA10 May Activate the Autophagic Process in Ovarian Endometriosis

Autophagy is a survival process that maintains homeostasis in all eukaryotic cells. Recent studies show an abnormal autophagic activity in endometriosis, but the role of autophagy is controversial. Homeobox A10 (HOXA10) is a transcription factor necessary for embryonic and adult uterine development, and studies indicate that its expression decreases in endometriosis. Homeobox A10 may negatively regulate autophagy in endometriosis. To test this hypothesis, we measured the expression levels of autophagic biomarkers (beclin-1 and LC3-II) and HOXA10 proteins by Western blotting and messenger RNA (mRNA) by quantitative real-time polymerase chain reaction. Furthermore, we evaluated the serum cancer antigen 125 (CA125) levels by immunoassay. Most tested autophagic biomarker proteins and mRNAs were upregulated, whereas HOXA10 protein and mRNA were decreased in ovarian endometriomas compared with eutopic endometria of women with endometriosis and normal endometria. Compared with normal endometrium, only protein expression levels of autophagic biomarkers were increased in the eutopic endometrium of women with endometriosis. Moreover, HOXA10 was found to have a significant negative correlation with autophagy ( P < .01). Serum CA125 was at a high level in endometriosis and increased with elevated revised American Fertility Society staging (I-IV). There was a significant positive correlation between serum CA125 level and LC3-II protein level and/or LC3-II/LC3-I ratio ( P < .01) and a significant negative correlation between serum CA125 level and HOXA10 gene level ( P < .01). In conclusion, our studies support that the deficiency of HOXA10 may induce autophagy in endometriosis, and the relationship among CA125, autophagy, and HOXA10 in endometriosis requires additional research.

Synergistic effect of regulatory T cells and proinflammatory cytokines in angiogenesis in the endometriotic milieu

STUDY QUESTION

Do regulatory T cells (Tregs) contribute to angiogenesis in endometriosis?

SUMMARY ANSWER

High levels of CCL17 and CCL22 cause the recruitment of Tregs, upregulate the immunosuppression of Tregs and, in turn, may promote angiogenesis in endometrial cells in synergy with proinflammatory cytokines.

WHAT IS ALREADY KNOWN

The peritoneal fluid of patients with endometriosis has a higher percentage of Tregs than that of normal individuals; however, the regulatory role of Tregs in the disease remains unclear.

STUDY DESIGN, SIZE, DURATION

This study used primary human endometrial stromal cells (ESCs), monocytes (Mo), Tregs and human umbilical vein endothelial cells (HUVECs). All experiments were performed at least three times.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The migration of Tregs was evaluated by the transwell migration assay. The activation of extracellular signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase and p38 signaling pathways was examined using the In-Cell WesternTM (LI-COR®) western blot analysis system, as well as by traditional western blot analysis. Changes in the expression of CCL22, CCL17, transforming growth factor-beta 1 (TGF-β1), Interleukin (IL)-1β, tumor necrosis factor alpha (TNF-α), IL-8 and vascular endothelial growth factor (VEGF) in cell-culture supernatant were detected by ELISA. We analyzed the Tregs by multicolor flow cytometry to directly test the expression of CCR4, CD4, CD25, Foxp3, CTLA-4, CD39 and CD73.

MAIN RESULTS AND THE ROLE OF CHANCE

Our results showed that ESCs-Mo co-culture produced significantly higher levels of CCL22 and CCL17 than ESCs or Mo cultured alone, and that estradiol (E2) or progesterone (P) further promoted this upregulation, demonstrating stronger chemotaxis on Tregs. The co-culture of ESCs with Mo stimulated TGF-β1 secretion by Tregs, which could be inhibited by anti-CCL22 or/and anti-CCL17 neutralizing antibodies (Abs). The expression of CCR4 by Tregs was upregulated in ESCs-Mo co-culture, especially by treatment with E2 and/or P, and this effect could be abolished by anti-CCL22 and/or anti-CCL17-neutralizing Abs. The Treg-ESCs-Mo co-culture treated with E2 (10-8 mol/l) and P (10-8 mol/l) could enhance the immunosuppression of Tregs, as proved by the elevated expression of Foxp3, CTLA-4, CD39 and CD73 on Tregs. ESCs-Mo co-culture could significantly promote the secretion of IL-1β and TNF-α. TGF-β1 from Tregs could activate p38/ERK1/2 signaling pathways in ESCs, and IL-1β and TNF-α produced by ESCs-Mo co-culture had synergistic roles with TGF-β1. TGF-β1 and the proinflammatory cytokines IL-1β or TNF-α could synergistically promote IL-8 and VEGF expression in ESCs via the p38/ERK1/2 signaling pathways. The high levels of IL-8 and VEGF in the supernatant of ESCs stimulated the angiogenesis of HUVECs.

LARGE SCALE DATA

None.

LIMITATIONS, REASONS FOR CAUTION

This study was only performed in vitro using eutopic ESCs, instead of ectopic cells, from endometriosis patients. Therefore, it is necessary to do further experiments to determine whether Tregs promote angiogenesis in the endometriotic milieu in synergy with proinflammatory cytokines in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

Co-targeting Tregs and proinflammatory cytokines may be an effective treatment for endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by Ministry of Science and Technology of China 2015CB943300 to L.D.-J.; National Natural Science Foundation of China, item number 81200425 to  W.X.-Q.; National Natural Science Foundation of China, item number 81471548 to L.D.-J.; and The Research Fund for the Doctoral Program of Higher Education of China to W.X.-Q. (20110071120093). The authors have no conflicts of interest to declare.

Identifying stably expressed housekeeping genes in the endometrium of fertile women, women with recurrent implantation failure and recurrent miscarriages

Housekeeping genes (HKG) are presumed to be constitutively expressed throughout tissue types but recent studies have shown they vary with pathophysiology. Often, validation of appropriate HKG is not made. There is no consensus on which HKGs are most stably expressed in endometrial tissue so this study aimed to identify the most stable HKG in the endometrium of women with recurrent implantation failure (RIF) and recurrent miscarriages (RM). Inclusion criteria were women between 25-45 years (n = 45) suffering recurrent miscarriage (RM), recurrent implantation failure (RIF) or fertile controls. Endometrial biopsies were taken and total RNA extraction, cDNA synthesis and PCR was performed using 10 candidate HKG. The genes were arranged in terms of stability and normalisation was determined. Several HKGs not previously tested in endometrial samples were found to be more stable than those previously identified as the most stable. Of these, the 5 most stable HKG (in order of stability) were Prdm4 (PR domain 4) > Ube4a (Ubiquitin-Conjugating Enzyme 4a) > Enox2 (Ecto-NOX Disulfide-Thiol Exchanger 2) > Ube2d2 (Ubiquitin-conjugating enzyme E2D 2) > Actb (Actin beta). We therefore recommend using at least four of the aforementioned HKG for normalisation of endometrial tissues taken from patients with RM and RIF.

CCDC22 gene polymorphism is associated with advanced stages of endometriosis in a sample of Brazilian women

PURPOSE

Based on the assumption that genetic factors are involved in the etiology of endometriosis, this study aimed to investigate the possibility of rs498679 (TLR4 gene), rs1799964 (TNF-α gene), rs3024496 (IL-10 gene), and rs2294021 (CCDC22 gene) polymorphisms being associated with the occurrence of this disease in a sample of Brazilian women.

METHODS

We conducted a case-control study with 100 women with histological confirmation of endometriosis (endometriosis group) and 100 women submitted to laparoscopy for benign disorders, in which the absence of endometriosis was confirmed (control group). All samples were genotyped by real-time PCR technique for rs498679, rs1799964, rs3024496, and rs2294021 polymorphisms.

RESULTS

No significant difference was observed in genotypic or allelic frequencies between control and endometriosis groups for rs498679 (TLR4 gene), rs1799964 (TNF-α gene), rs3024496 (IL-10 gene), neither when comparing endometriosis subgroups (I-II versus III-IV). On the other hand, significant difference between stages I-II and III-IV of the disease was found in genotypic and allelic frequencies for the rs2294021 (CCDC22 gene) SNP (p = 0.048 and p = 0.017, respectively).

CONCLUSION

Our results suggest that the rs2294021 (CCDC22 gene) polymorphism could be associated with increased susceptibility to endometriosis in Brazilian women when the allele C is present. In order to clarify this result, further studies should be conducted on a larger population.

Soluble VCAM-1/soluble ICAM-1 ratio is a promising biomarker for diagnosing endometriosis

Study question

Do cell adhesion molecules play a role in endometriosis, and can they be used as a biomarker for diagnosing endometriosis?

Summary answer

Altered expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) in the endometrium and peritoneum may play a key role in endometriosis and the soluble VCAM-1/soluble ICAM-1 ratio is a promising biomarker.

What is known already

Cell adhesion molecules are cell surface proteins that mediate cellular adherence, inflammatory and immune responses, and cancer-related biological processes. Altered expression of VCAM-1 and ICAM-1 in women with endometriosis has been investigated previously; however, gene expression levels in tissues and protein levels in the serum have not been investigated in the same patients.

Study design size, duration

We performed a prospective, longitudinal study (the Endometriosis Marker Austria) in patients who underwent a laparoscopy for benign gynecological pathology in a university-based tertiary referral center for endometriosis. From a total of 138 women who were included in the study from July 2013 through September 2014, 97 had not received hormonal treatment for at least 3 months prior to recruitment and were included in the analysis; 49 (50.5%) of these women had endometriosis, and the 48 (49.5%) who did not have endometriosis served as a control group.

Participants/materials setting methods

During laparoscopy, tissue samples were obtained from ectopic and eutopic endometrium, and from normal pelvic peritoneum. In addition, serum samples were collected immediately before and 6-10 weeks after surgery. The mRNA levels of VCAM-1, ICAM-1 and epithelial cell adhesion molecule (EpCAM) were measured using quantitative real-time PCR, and serum protein levels of soluble VCAM-1 (sVCAM-1), ICAM-1 (sICAM-1) and EpCAM (sEpCAM) were measured using ELISA and correlated with endometriosis status.

Main results and the role of chance

The mRNA levels of both VCAM-1 and ICAM-1 were higher in ectopic endometriotic lesions than in eutopic endometrium (P < 0.001). Moreover, the mRNA levels of both VCAM-1 and ICAM-1 were higher in normal peritoneum samples obtained from women with endometriosis compared to those from controls (P = 0.038 and P = 0.009). The mRNA levels of VCAM-1 were also higher in the eutopic endometrium samples obtained from women with endometriosis compared to controls (P = 0.018). With respect to serum protein levels, compared to controls, the women with endometriosis had lower serum levels of sICAM-1 (P = 0.042) and higher levels of sVCAM-1 (P < 0.001). Our analysis revealed that the serum levels of sVCAM-1 were not affected by lesion entity, menstrual cycle phase or disease severity. An receiver operating characteristics curve, calculated to determine whether preoperative serum sVCAM-1 concentration can be used to predict endometriosis, found an AUC of 0.868 with 80% specificity and 84% sensitivity at a cutoff value of 370 pg/ml. This predictive performance can be further improved by calculation of the sVCAM-1/sICAM-1 ratio, leading to an AUC of 0.929 with 86.7% specificity and 90.3% sensitivity at a cutoff ratio value of 1.55.

Large scale data

Not applicable.

Limitations reasons for caution

The relatively small sample size in the expression analyses is a possible limitation of this study.

Wider implications of the findings

Our findings could contribute to an improved understanding of the pathogenesis of endometriosis and the role of cell adhesion molecules. In addition, the results may lead to the development of new, non-invasive tools for diagnosing endometriosis. The ability to diagnose patients by measuring serum sVCAM-1 levels or the sVCAM-1/sICAM-1 ratio would have considerable clinical value.

Study funding/competing interest(s)

The Ingrid Flick Foundation (Grant no. FA751C0801), which played no role in the study design, data collection and analysis, decision to publish or preparation of the manuscript. The authors declare no competing interests.

Specific Photothermal Ablation Therapy of Endometriosis by Targeting Delivery of Gold Nanospheres

Endometriosis is difficult to treat since the side effects of the current therapeutic method and the high recurrence rate; thus, newer and safer therapeutic approaches are urgently needed. This work investigates the enhanced permeability and retention effect of CdTe quantum dots (QDs) and hollow gold nanospheres (HAuNS) in endometriosis to increase the delivery of HAuNS into lesion cells. The surface of HAuNS is successfully conjugated with a TNYL peptide that has specific affinity for the EphB4 receptor, which is a member of the Eph family of receptor tyrosine kinases. It is found that the EphB4 receptor is overexpressed in endometriosis lesions. The data indicate that both QDs and HAuNS can efficiently accumulate in endometriotic lesions through permeable vessels and the TNYL-conjugated HAuNS (TNYL-HAuNS) accumulate more via the interaction with EphB4. The specific photothermal ablation therapy based on TNYL-HAuNS significantly inhibits the growth of the endometriotic volume and induces the atrophy and degeneration of ectopic endometrium with no detectable toxicity to the normal organs. The level of TNF-α and estradiol also significantly decreases in the endometriotic lesions, indicating that the treatment enables a recovery from hormonal imbalance and inflammatory injury. This work can be a valuable reference for future endometriosis therapy.

Innovative approach in assessing the role of neurogenesis, angiogenesis, and lymphangiogenesis in the pathogenesis of external genital endometriosis

Endometriosis is a chronic, progressive, relapsing estrogen-dependent disorder characterized by the growth of tissue structure and function similar to the endometrium outside the normal mucosa of the uterine cavity localization. Endometriosis is found in 10-15% of women in reproductive age and it is one of the main causes of pelvic pain syndrome and infertility. Mechanisms of the development of endometriosis and related pathological pain impulses are still poorly understood and therapeutic approaches do not always have a sufficient effect; in this connection, the study of the pathogenesis of endometriosis and endometriosis-associated pain currently is perspective. Identification of significant factors of angiogenesis, lymphangiogenesis, and neurogenesis in the external genital endometriosis will promote the development of non-invasive early diagnosis and pathogenetic therapy.

Endometrial biomarkers for the non-invasive diagnosis of endometriosis

BACKGROUND

About 10% of reproductive-aged women suffer from endometriosis, which is a costly, chronic disease that causes pelvic pain and subfertility. Laparoscopy is the gold standard diagnostic test for endometriosis, but it is expensive and carries surgical risks. Currently, there are no non-invasive tests available in clinical practice that accurately diagnose endometriosis. This is the first diagnostic test accuracy review of endometrial biomarkers for endometriosis that utilises Cochrane methodologies, providing an update on the rapidly expanding literature in this field.

OBJECTIVES

To determine the diagnostic accuracy of the endometrial biomarkers for pelvic endometriosis, using a surgical diagnosis as the reference standard. We evaluated the tests as replacement tests for diagnostic surgery and as triage tests to inform decisions to undertake surgery for endometriosis.

SEARCH METHODS

We did not restrict the searches to particular study designs, language or publication dates. To identify trials, we searched the following databases: CENTRAL (2015, July), MEDLINE (inception to May 2015), EMBASE (inception to May 2015), CINAHL (inception to April 2015), PsycINFO (inception to April 2015), Web of Science (inception to April 2015), LILACS (inception to April 2015), OAIster (inception to April 2015), TRIP (inception to April 2015) and ClinicalTrials.gov (inception to April 2015). We searched DARE and PubMed databases up to April 2015 to identify reviews and guidelines as sources of references to potentially relevant studies. We also performed searches for papers recently published and not yet indexed in the major databases. The search strategies incorporated words in the title, abstract, text words across the record and the medical subject headings (MeSH).

SELECTION CRITERIA

We considered published peer-reviewed, randomised controlled or cross-sectional studies of any size that included prospectively collected samples from any population of reproductive-aged women suspected of having one or more of the following target conditions: ovarian, peritoneal or deep infiltrating endometriosis (DIE).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from each study and performed a quality assessment. For each endometrial diagnostic test, we classified the data as positive or negative for the surgical detection of endometriosis and calculated the estimates of sensitivity and specificity. We considered two or more tests evaluated in the same cohort as separate data sets. We used the bivariate model to obtain pooled estimates of sensitivity and specificity whenever sufficient data were available. The predetermined criteria for a clinically useful test to replace diagnostic surgery was one with a sensitivity of 94% and a specificity of 79%. The criteria for triage tests were set at sensitivity at or above 95% and specificity at or above 50%, which in case of negative results rules out the diagnosis (SnOUT test) or sensitivity at or above 50% with specificity at or above 95%, which in case of positive result rules in the diagnosis (SpIN test).

MAIN RESULTS

We included 54 studies involving 2729 participants, most of which were of poor methodological quality. The studies evaluated endometrial biomarkers either in specific phases of the menstrual cycle or outside of it, and the studies tested the biomarkers either in menstrual fluid, in whole endometrial tissue or in separate endometrial components. Twenty-seven studies evaluated the diagnostic performance of 22 endometrial biomarkers for endometriosis. These were angiogenesis and growth factors (PROK-1), cell-adhesion molecules (integrins α3β1, α4β1, β1 and α6), DNA-repair molecules (hTERT), endometrial and mitochondrial proteome, hormonal markers (CYP19, 17βHSD2, ER-α, ER-β), inflammatory markers (IL-1R2), myogenic markers (caldesmon, CALD-1), neural markers (PGP 9.5, VIP, CGRP, SP, NPY, NF) and tumour markers (CA-125). Most of these biomarkers were assessed in single studies, whilst only data for PGP 9.5 and CYP19 were available for meta-analysis. These two biomarkers demonstrated significant diversity for the diagnostic estimates between the studies; however, the data were too limited to reliably determine the sources of heterogeneity. The mean sensitivities and specificities of PGP 9.5 (7 studies, 361 women) were 0.96 (95% confidence interval (CI) 0.91 to 1.00) and 0.86 (95% CI 0.70 to 1.00), after excluding one outlier study, and for CYP19 (8 studies, 444 women), they were were 0.77 (95% CI 0.70 to 0.85) and 0.74 (95% CI 0.65 to 84), respectively. We could not statistically evaluate other biomarkers in a meaningful way. An additional 31 studies evaluated 77 biomarkers that showed no evidence of differences in expression levels between the groups of women with and without endometriosis.

AUTHORS' CONCLUSIONS

We could not statistically evaluate most of the biomarkers assessed in this review in a meaningful way. In view of the low quality of most of the included studies, the findings of this review should be interpreted with caution. Although PGP 9.5 met the criteria for a replacement test, it demonstrated considerable inter study heterogeneity in diagnostic estimates, the source of which could not be determined. Several endometrial biomarkers, such as endometrial proteome, 17βHSD2, IL-1R2, caldesmon and other neural markers (VIP, CGRP, SP, NPY and combination of VIP, PGP 9.5 and SP) showed promising evidence of diagnostic accuracy, but there was insufficient or poor quality evidence for any clinical recommendations. Laparoscopy remains the gold standard for the diagnosis of endometriosis, and using any non-invasive tests should only be undertaken in a research setting. We have also identified a number of biomarkers that demonstrated no diagnostic value for endometriosis. We recommend that researchers direct future studies towards biomarkers with high diagnostic potential in good quality diagnostic studies.

The Serum Levels of the Soluble Factors sCD40L and CXCL1 Are Not Indicative of Endometriosis

Endometriosis is a benign but troublesome gynecological condition, characterized by endometrial-like tissue outside the uterine cavity. Lately, the discovery and validation of noninvasive diagnostic biomarkers for endometriosis is one of the main priorities in the field. As the disease elicits a chronic inflammatory reaction, we focused our interest on two factors well known to be involved in inflammation and neoplastic processes, namely, soluble CD40 Ligand and CXCL1, and asked whether differences in the serum levels of sCD40L and CXCL1 in endometriosis patients versus controls can serve as noninvasive disease markers. A total of n = 60 women were included in the study, 31 endometriosis patients and 29 controls, and the serum levels of sCD40L and CXCL1 were measured by enzyme-linked immunosorbent assay. Overall, there were no statistically significant differences in the levels of expression of both sCD40L and CXCL1 between patients and controls. This study adds useful clinical data showing that the serum levels of the soluble factors sCD40L and CXCL1 are not associated with endometriosis and are not suitable as biomarkers for disease diagnosis. However, we found a trend toward lower levels of sCD40L in the deep infiltrating endometriosis subgroup making it a potentially interesting target worth further investigation.

Challenges in the development of novel therapeutic strategies for treatment of endometriosis

INTRODUCTION

Endometriosis is an estrogen-dependent disease that results in pelvic pain and infertility. Its treatment is often frustrating due to limited medical treatment options, complex surgical treatment and high recurrence rates. Despite the advances in our understanding of the pathogenesis over the last decades and the consequent novel therapeutic strategies, no new drugs have been introduced in daily clinical practice.

AREAS COVERED

In the first part we present an overview of the pathogenesis of endometriosis. In the second part we discuss how new insights have led to the development of novel nonhormonal strategies for the treatment of endometriosis, focusing on anti-inflammatory and anti-angiogenic agents. In the third part we describe the problems encountered in the translation from experimental drugs to routine medicine for the treatment of endometriosis.

EXPERT OPINION

Despite the multitude of agents that have been tested in preclinical trials, only few drugs have passed to the stage of clinical testing and none have been introduced into clinical practice. It is our opinion that the major challenges in the translation from novel agents for endometriosis is due to the use of inadequate rodent models and a lack of standardization in the design and reporting of preclinical endometriosis models.

Increased association between endometriosis and endometrial cancer: a nationwide population-based retrospective cohort study

Objective

Association between endometriosis and ovarian cancer has been well established. Nonetheless, endometriosis may also be associated with endometrial cancer because of shared etiological mechanisms of both estrogen stimulation and chronic inflammation; however, the association between these 2 disorders has rarely been investigated.

Methods

The National Health Insurance Research Databases in Taiwan were retrieved and analyzed. The case cohort consisted of patients with a diagnosis of endometriosis between January 1997 and December 2000 (N = 15,488). For the construction of control cohort, 8 age- and sex-matched control patients for every patient in the case cohort were selected using a random sampling method (n = 123,904). All subjects were tracked for 10 years from the date of entry to identify whether they had developed endometrial cancer. The Cox proportional hazards regression model was used to evaluate 10-year event occurrence of endometrial cancer.

Results

During the 10-year follow-up period, 392 participants developed endometrial cancer, with 104 (0.7%) distributed in the case cohort and 288 (0.2%) in the control cohort. Multivariable Cox regression modeling demonstrates a higher risk for developing endometrial cancer in the case cohort than in the control cohort (adjusted hazard ratio [aHR], 2.83; 95% confidence interval [CI], 1.495.35; P < 0.01). Age at diagnosis of endometriosis shows a moderator effect: when 40 years or younger, the risk for developing endometrial cancer was comparable between the case cohort and the control cohort (aHR, 1.42; 95% CI, 0.55–3.70; P = 0.226), whereas when older than 40 years, the risk for developing endometrial cancer was higher in the former group than in the latter group (aHR, 7.08; 95% CI, 2.33–21.55; P = 0.007).

Conclusions

Patients diagnosed with endometriosis may harbor an increased risk for developing endometrial cancer in their later life. Closer monitoring is advised for this patient population.

Evaluation of Tumor Necrosis Factor Alpha Polymorphism Frequencies in Endometriosis

BACKGROUND

The pro-inflammatory cytokine, tumor necrosis factor-alpha (TNF-α), is a pathogenic element for a number of disorders. Previous studies have reported that the -1031 T/C and -238 G/A polymorphisms in the promoter region of the TNF-α gene are important factors in reproductive-related disorders. One of the most common gynecological diseases of women during the reproductive years is endometriosis. This study aims to assess an association between the -1031 T/C, -238 G/A and -308 G/A polymorphisms of the TNF-α gene promoter region to endometriosis.

MATERIALS AND METHODS

In this case-control study, we enrolled 65 endometriosis patients and 65 matched healthy control women by simple sampling. Polymerase chain reaction (PCR) analysis was used to analyze -1031 T/C, -238 G/A and -308 G/A polymorphisms in the TNF-α gene promoter region. Statistical analysis was performed using the chi-square test. P values less than 0.05 were considered statistically significant.

RESULTS

We found a strong association between the -1031 T/C polymorphism in the promoter region of the TNF-α gene with endometriosis (P=0.001). There were no significant associations between the -238 G/A (P=0.243) and -308 G/A (P=1) polymorphisms with endometriosis and again endometriosis stages have no association with these polymorphisms.

CONCLUSION

The -1031 T/C polymorphism and CC genotype can be used as a relevant marker to identify women at risk of developing endometriosis.

The Association between Endometriomas and Ovarian Cancer: Preventive Effect of Inhibiting Ovulation and Menstruation during Reproductive Life

Although endometriosis frequently involves multiple sites in the pelvis, malignancies associated with this disease are mostly confined to the ovaries, evolving from an endometrioma. Endometriomas present a 2-3-fold increased risk of transformation in clear-cell, endometrioid, and possibly low-grade serous ovarian cancers, but not in mucinous ovarian cancers. These last cancers are, in some aspects, different from the other epithelial ovarian cancers, as they do not appear to be decreased by the inhibition of ovulation and menstruation. The step by step process of transformation from typical endometrioma, through atypical endometrioma, finally to ovarian cancer seems mainly related to oxidative stress, inflammation, hyperestrogenism, and specific molecular alterations. Particularly, activation of oncogenic KRAS and PI3K pathways and inactivation of tumor suppressor genes PTEN and ARID1A are suggested as major pathogenic mechanisms for endometriosis associated clear-cell and endometrioid ovarian cancer. Both the risk for endometriomas and their associated ovarian cancers seems to be highly and similarly decreased by the inhibition of ovulation and retrograde menstruation, suggesting a common pathogenetic mechanism and common possible preventive strategies during reproductive life.

Co-operation between the AKT and ERK signaling pathways may support growth of deep endometriosis in a fibrotic microenvironment in vitro

STUDY QUESTION

How can deep endometriotic stromal cells proliferate and persist in a fibrotic environment?

SUMMARY ANSWER

The serine/threonine kinase AKT and extracellular regulated kinase (ERK) signaling pathways may co-operate to support growth of deep endometriotic lesions by enhancing endometriotic stromal cell proliferation and survival in a fibrotic microenvironment in vitro.

WHAT IS KNOWN ALREADY

Endometriosis, particularly deep infiltrating endometriosis, is characterized histologically by dense fibrous tissue that is primarily composed of type I collagen. This tissue may cause pelvic pain and infertility, which are major clinical issues associated with endometriosis. Proliferation of normal fibroblasts is tightly regulated, and fibrillar, polymerized type I collagen inhibits normal fibroblast proliferation. However, no studies to date have investigated how deep endometriotic stromal cells can proliferate and persist in a fibrotic environment.

STUDY DESIGN, SIZE, DURATION

Endometrial and/or endometriotic tissues from 104 patients (61 with and 43 without endometriosis) of reproductive age with normal menstrual cycles were analyzed. A total of 25 nude mice received a single injection of endometrial fragments from a total of five samples.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We evaluated cell proliferation, caspase 3/7 activity, and the AKT and ERK signaling pathways in endometrial and endometriotic stromal cells on three-dimensional (3D) polymerized collagen matrices in vitro. In addition, to determine whether aberrant activation of the AKT and ERK pathways is involved during progression of fibrosis in endometriosis in vivo, we evaluated the expression of phosphorylated AKT and ERK1/2 in endometriotic implants in a nude mouse model of endometriosis. Finally, we evaluated the effects of MK2206 (an AKT inhibitor) and U0126 (a MEK inhibitor) on cell proliferation, caspase 3/7 activity, and phosphorylation of AKT and ERK1/2 of endometriotic stromal cells on 3D polymerized collagen matrices.

MAIN RESULTS AND THE ROLE OF CHANCE

Proliferation of endometriotic stromal cells was significantly less inhibited than that of endometrial stromal cells (P < 0.05) on 3D polymerized collagen. Levels of phosphorylated AKT, phosphorylated p70S6K and phosphorylated ERK1/2 were significantly higher in endometriotic stromal cells than in endometrial stromal cells at 24 h (P < 0.05) and at 72 h (P < 0.05) on 3D polymerized collagen. Phosphorylated AKT expression was significantly increased on Days 21 and 28 compared with those on Days 3 and 7 (all P < 0.05) in endometriotic implants during progression of fibrosis in a nude mouse model of endometriosis. Inhibition of AKT or ERK1/2 with MK2206 or U0126, respectively, did not significantly increase caspase 3/7 activity in endometriotic stromal cells on either two-dimensional or 3D collagen matrices. Western blot analysis showed that MK2206 alone decreased levels of phosphorylated AKT; however, it increased levels of phosphorylated ERK in endometriotic cells compared with vehicle-treated cells (both P < 0.05). In addition, U0126 treatment decreased levels of phosphorylated ERK; however, it resulted in increased levels of phosphorylated AKT in endometriotic stromal cells compared with vehicle-treated cells (both P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

Endometriosis involves a number of processes, such as invasion, metastasis, angiogenesis, and apoptosis resistance, and a variety of signaling pathways may be involved in promoting development and progression of the disease. In addition, further animal experiments are required to determine whether the AKT and ERK signaling pathways co-operate to support growth of endometriotic lesions in a fibrotic microenvironment in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

Co-targeting the AKT and ERK pathways may be an effective therapeutic strategy for endometriosis treatment.

STUDY FUNDING/COMPETING INTERESTS

This study was supported in part by Karl Storz Endoscopy & GmbH (Tuttlingen, Germany). No competing interests are declared.

World Endometriosis Research Foundation Endometriosis Phenome and Biobanking Harmonization Project: III. Fluid biospecimen collection, processing, and storage in endometriosis research

Objective

To harmonize standard operating procedures (SOPs) and standardize the recording of associated data for collection, processing, and storage of fluid biospecimens relevant to endometriosis.

Design

An international collaboration involving 34 clinical/academic centers and 3 industry collaborators from 16 countries on 5 continents.

Setting

In 2013, 2 workshops were conducted, followed by global consultation, bringing together 54 leaders in endometriosis research and sample processing worldwide.

Patient(s)

None.

Intervention(s)

Consensus SOPs were based on: [1] systematic comparison of SOPs from 18 global centers collecting fluid samples from women with and without endometriosis on a medium/large scale (publication on >100 cases), [2] literature evidence where available, or consultation with laboratory experts otherwise, and [3] several global consultation rounds.

Main Outcome Measure(s)

Standard recommended and minimum required SOPs for biofluid collection, processing, and storage in endometriosis research.

Result(s)

We developed recommended standard and minimum required SOPs for the collection, processing, and storage of plasma, serum, saliva, urine, endometrial/peritoneal fluid, and menstrual effluent, and a biospecimen data-collection form necessary for interpretation of sample-derived results.

Conclusion(s)

The Endometriosis Phenome and Biobanking Harmonisation Project SOPs allow endometriosis research centers to decrease variability in biofluid sample results, facilitating between-center comparisons and collaborations. The procedures are also relevant to research into other female conditions involving biofluid samples subject to cyclic reproductive influences. The consensus SOPs are based on the best available evidence; areas with limited evidence are identified as requiring further pilot studies. The SOPs will be reviewed based on investigator feedback, and through systematic tri-annual follow-up. Updated versions will be made available at: endometriosisfoundation.org/ephect.

Identification of local angiogenic and inflammatory markers in the menstrual blood of women with endometriosis

The aim of this study was to evaluate the presence of myeloperoxidase (MPO), N-acetyl-β-D-glucosaminidase (NAG), tumor necrosis factor alpha (TNF-α) and vascular endothelial growth factor (VEGF) in peripheral and menstrual blood in women with (n=10) and without (n=7) endometriosis. NAG and MPO activities were evaluated by enzymatic methods, whereas TNF-α and VEGF by immunoassay. No significant differences were found for these markers, neither in menstrual nor in peripheral blood between groups. Menstrual blood NAG (P=0.039) and MPO (P=0.0117) activities in the endometriosis group were significantly higher than in peripheral blood. NAG and MPO presented positive linear correlation in peripheral (P=0.07; r=0.641) and menstrual blood (P=0.01; r=0.603). These findings point to the existence of an increased local inflammatory activity in women with endometriosis.

Blood soluble interleukin 1 receptor accessory protein levels are consistently low throughout the menstrual cycle of women with endometriosis

BACKGROUND

A deficiency in the counter-regulatory mechanisms of interleukin 1 (IL1) may play a significant role in endometriosis pathogenesis and associated chronic inflammation. The aim of this study was to investigate peripheral blood levels of soluble IL1 receptor accessory protein (sIL1RAP), a potent natural inhibitor of IL1, in women with and without endometriosis.

METHODS

Peripheral blood samples were collected from women with endometriosis (n = 47) consulting for infertility, pelvic pain or tubal ligation, in whom the disease was diagnosed at laparoscopy. Control healthy women (n = 27) were requesting tubal ligation or reanastomosis and had no visible evidence of endometriosis at laparoscopy. sIL1RAP levels were determined by ELISA, whereas estradiol (E2) and progesterone (P4) levels were determined by competitive immunoassays.

RESULTS

sIL1RAP levels were significantly decreased in women with early endometriosis stages compared to controls (p < 0.05) and markedly during the proliferative phase of the menstrual cycle (p < 0.001). Actually, while sIL1RAP were significantly increased in the proliferative compared to the secretory phase in normal women (p < 0.0001) and peaked at the end of this phase, sIL1RAP remained consistently low and showed non-significant variations throughout the menstrual cycle in women with endometriosis.

CONCLUSIONS

Lower circulating levels of sIL1RAP points to a significant impairment in the counter-regulatory mechanisms of IL1, which in view of the cytokine's potent inflammatory and growth-promoting properties may play a significant role in the pathophysiology of endometriosis.

Krüppel-like factor 9 deficiency in uterine endometrial cells promotes ectopic lesion establishment associated with activated notch and hedgehog signaling in a mouse model of endometriosis

Endometriosis, a steroid hormone-dependent disease characterized by aberrant activation of estrogen receptor signaling and progesterone resistance, remains intractable because of the complexity of the pathways underlying its manifestation. We previously showed that eutopic endometria of women with endometriosis exhibit lower expression of Krüppel-like factor 9 (KLF9), a progesterone receptor coregulator in the uterus, relative to that of women without disease. Here we examined whether loss of endometrial KLF9 expression causes ectopic lesion establishment using syngeneic wild-type (WT) mice as recipients of endometrial fragments from WT and Klf9 null donors. We found significantly higher incidence of ectopic lesions with Klf9 null than WT endometria 8 weeks after tissue injection into the intraperitoneal cavity. The increased incidence of lesion establishment with Klf9 null endometria was associated with a higher expression ratio of estrogen receptor 2 isoform relative to that of estrogen receptor 1 and attenuated progesterone receptor levels in endometriotic stromal cells. PCR array analyses of Notch and Hedgehog signaling components in ectopic lesions demonstrated up-regulated expression of select genes (Jag 2, Shh, Gli1, and Stil 1) in Klf9 null lesions relative to that in WT lesions. Immunohistochemical analyses showed increased levels of Notch intracellular domain and Sonic Hedgehog proteins in Klf9 null lesions relative to that in WT lesions, confirming pathway activation. WT recipients with Klf9 null lesions displayed lower systemic levels of TNFα and IL-6 and higher soluble TNF receptor 1 than corresponding recipients with WT lesions. Our results suggest that endometrial KLF9 deficiency promotes endometriotic lesion establishment by the coincident deregulation of Notch-, Hedgehog-, and steroid receptor-regulated pathways.