Neutrophil recruitment and function in endometriosis patients and a syngeneic murine model

Patterns of proliferation and fibrosis in a rat model of endometriosis following administration of Allium cepa

OBJECTIVE

Endometriosis is a common gynecological disease among reproductive-age women. Numerous hypotheses exist regarding the pathogenesis of endometriosis. In Turkey, the consumption of Allium cepa (commonly known as the "onion cure") is a popular treatment employed to alleviate a variety of gynecological disorders.

METHODS

In this study, our objective was to assess the therapeutic mechanisms of the onion bulb A. cepa using an autologous endometriosis model in Sprague-Dawley rats. Previous research has shown that A. cepa possesses anti-inflammatory, antioxidant, and antiapoptotic properties. We evaluated the pathological condition of endometriotic implants by employing hematoxylin-eosin staining and Ki67 immunohistochemistry analysis. Transforming growth factor-beta 1 (TGF-β1) and alpha-smooth muscle actin (α-SMA) have been identified as profibrotic markers that are highly overexpressed in endometriotic tissues relative to eutopic endometrial tissue. Furthermore, TGF-β1 influences the differentiation and progression of endometriosis. To quantify profibrotic activity, we measured TGF-β1 and α-SMA using the immunosorbent assay method.

RESULTS

Lower histologic evaluation scores for endometriotic implants were observed in the group receiving high-dose A. cepa relative to the other groups. Ki67 expression was reduced following the high-dose A. cepa regimen, which consisted of 30% A. cepa and 70% normal feed. However, no statistically significant differences in TGF-β1 or α-SMA levels were observed among the groups (p=0.7 and p=0.778, respectively).

CONCLUSION

The findings suggest that A. cepa could serve as a therapeutic agent in endometriosis treatment, as evidenced by the reduction in proliferative potential. Nevertheless, A. cepa was not associated with significantly lower levels of endometriosis-associated TGF-β1 or α-SMA.

The Dysregulated IL-23/TH17 Axis in Endometriosis Pathophysiology

Endometriosis is a chronic inflammatory disease in which endometrial-like tissue grows ectopically, resulting in pelvic pain and infertility. IL-23 is a key contributor in the development and differentiation of TH17 cells, driving TH17 cells toward a pathogenic profile. In a variety of inflammatory and autoimmune disorders, TH17 cells secrete proinflammatory cytokines, including IL-17, contributing to disease pathophysiology. Our studies and others have implicated IL-17 and TH17 cell dysregulation in endometriosis, which is associated with disease severity. In this article, we address whether IL-23-driven TH17 cells contribute to cardinal features of lesion proliferation, vascularization, and inflammation in endometriosis using patient samples, representative cell lines, and our established mouse model of endometriosis. The results indicated dysregulated expression of key genes in the IL-23/TH17 axis in patient ectopic and eutopic endometrial samples and increased IL-23 protein in patient plasma compared with controls. In vitro studies using primary human TH cells determined that rIL-23 mixture treatment increased pathogenic TH17 cell frequency. Similarly, rIL-23 treatment of cell lines (12Z cells, EECCs, HUVECs, and hESCs) representative of the endometriotic lesion microenvironment increased cytokines and growth factors, which play a role in lesion establishment and maintenance. In a syngeneic mouse model of endometriosis, rIL-23 treatment altered numbers of myeloid and T cell subsets in peritoneal fluid and increased giant cells within the lesion. Lesions from rIL-23-treated mice did not reveal significant alterations in proliferation/vascularization, although trends of increased proliferation and vascularization were observed. Collectively, these findings provide insights into the impact of the IL-23/TH17 axis on local immune dysfunction and broadly on endometriosis pathophysiology.

The landscape of non-coding RNAs in the immunopathogenesis of Endometriosis

Endometriosis is a complex disorder that is characterized by the abnormal growth of endometrial-like tissue outside the uterus. It is associated with chronic inflammation, severe pelvic pain, infertility, and significantly reduced quality of life. Although the exact mechanism of endometriosis remains unknown, inflammation and altered immunity are considered key factors in the immunopathogenesis of the disorder. Disturbances of immune responses result in reduced clearance of regurgitated endometrial cells, which elicits oxidative stress and progression of inflammation. Proinflammatory mediators could affect immune cells' recruitment, fate, and function. Reciprocally, the activation of immune cells can promote inflammation. Aberrant expression of non-coding RNA (ncRNA) in patient and animal lesions could be suggestive of their role in endometriosis establishment. The engagement of these RNAs in regulating diverse biological processes, including inflammatory responses and activation of inflammasomes, altered immunity, cell proliferation, migration, invasion, and angiogenesis are widespread and far-reaching. Therefore, ncRNAs can be identified as a determining candidate regulating the inflammatory responses and immune system. This review aims in addition to predict the role of ncRNAs in the immunopathogenesis of endometriosis through regulating inflammation and altered immunity based on previous studies, it presents a comprehensive view of inflammation role in the pathogenesis of endometriosis.

Investigation of the Changes in Concentrations of Vitamin D-Binding Protein and Lactoferin in Plasma and Peritoneal Fluid of Patients with Endometriosis

An evaluation of the association between the concentrations of vitamin D-binding protein and lactoferrin in the plasma and peritoneal fluid may facilitate the elucidation of molecular mechanisms in endometriosis. Vitamin D-binding protein and lactoferrin concentrations were measured by ELISA in plasma and peritoneal fluid samples from 95 women with suspected endometriosis as classified by laparoscopy into groups with (n = 59) and without endometriosis (n = 36). There were no differences (p > 0.05) in the plasma and peritoneal fluid concentrations of vitamin D-binding protein and lactoferrin between women with and without endometriosis. In women with endometriosis, there was a significant correlation between plasma and peritoneal fluid vitamin D-binding protein concentrations (r = 0.821; p = 0.000), but there was no correlation between lactoferrin concentrations in those compartments (r = 0.049; p > 0.05). Furthermore, in endometriosis, lactoferrin was found to correlate poorly with vitamin D-binding protein (r= -0.236; p > 0.05) in plasma, while in the peritoneal fluid, the correlation between those proteins was significant (r = 0.399; p = 0.002). The characteristic properties of vitamin D-binding protein and lactoferrin and the associations between their plasma and peritoneal fluid concentrations found in women with endometriosis may provide a novel panel of markers to identify high-risk patients in need of further diagnostic measures.

The dysregulation of leukemia inhibitory factor and its implications for endometriosis pathophysiology

Endometriosis is an estrogen dominant, chronic inflammatory disease characterized by the growth of endometrial-like tissue outside of the uterus. The most common symptoms experienced by patients include manifestations of chronic pelvic pain- such as pain with urination, menstruation, or defecation, and infertility. Alterations to Leukemia Inhibitory Factor (LIF), a cytokine produced by the luminal and glandular epithelium of the endometrium that is imperative for successful pregnancy, have been postulated to contribute to infertility. Conditions such as recurrent implantation failure, unexplained infertility, and infertility associated diseases such as adenomyosis and endometriosis, have demonstrated reduced LIF production in the endometrium of infertile patients compared to fertile counterparts. While this highlights the potential involvement of LIF in infertility, LIF is a multifaceted cytokine which plays additional roles in the maintenance of cell stemness and immunomodulation. Thus, we sought to explore the implications of LIF production within ectopic lesions on endometriosis pathophysiology. Through immunohistochemistry of an endometrioma tissue microarray and ELISA of tissue protein extract and peritoneal fluid samples, we identify LIF protein expression in the ectopic lesion microenvironment. Targeted RT qPCR for LIF and associated signaling transcripts, identify LIF to be significantly downregulated in the ectopic tissue compared to eutopic and control while its receptor, LIFR, is upregulated, highlighting a discordance in ectopic protein and mRNA LIF expression. In vitro treatment of endometriosis representative cell lines (12Z and hESC) with LIF increased production of immune-recruiting cytokines (MCP-1, MCP-3) and the angiogenic factor, VEGF, as well as stimulated tube formation in human umbilical vein endothelial cells (HUVECs). Finally, LIF treatment in a syngeneic mouse model of endometriosis induced both local and peripheral alterations to immune cell phenotypes, ultimately reducing immunoregulatory CD206+ small peritoneal macrophages and T regulatory cells. These findings suggest that LIF is present in the ectopic lesions of endometriosis patients and could be contributing to lesion vascularization and immunomodulation.

Highly specific neutrophil-mediated delivery of albumin nanoparticles to ectopic lesion for endometriosis therapy

Endometriosis is an estrogen-dependent chronic inflammatory disease. Hormonal and surgical treatments are the most commonly used clinical therapies, but they have many sides effects or are traumatic to the body. Therefore, specific drugs for endometriosis treatment are urgently needed to develop. In this study, we identified two features of endometriosis, namely the continuous recruitment of neutrophils into the ectopic lesions and the higher uptake of glucose by ectopic cells. For the above features, we designed a glucose oxidase-loaded bovine serum albumin nanoparticle (BSA-GOx-NPs) that is inexpensive and facilitates large-scale production. After injection, BSA-GOx-NPs were high specifically delivered to ectopic lesions in a neutrophil-dependent manner. Furthermore, BSA-GOx-NPs deplete glucose and induce apoptosis in the ectopic lesions. Whereupon BSA-GOx-NPs produced excellent anti-endometriosis effects when administrated in both acute and chronic inflammatory phases. These results reveal for the first time that the neutrophil hitchhiking strategy is effective in chronic inflammatory disease and provide a non-hormonal and easy-to-achieve approach for endometriosis treatment.

The Abundance and Function of Neutrophils in the Endometriosis Systemic and Pelvic Microenvironment

Endometriosis is a common inflammatory illness in which endometrial tissue grows outside the uterine cavity. Immune dysfunction is now widely acknowledged as the primary cause of endometriosis. The immune cell population represented by neutrophils is thought to play an essential role in the etiology, pathophysiology, and associated clinical outcome. There is growing evidence that neutrophils have a role in chronic and aseptic inflammatory diseases, and endometriosis patients have increased levels of neutrophils in plasma, peritoneal fluid, and ectopic endometrium. Here, we sought to review the function of neutrophils in the pathogenesis of endometriosis, with an emphasis on the role of neutrophils in regulating endometrial angiogenesis and the local inflammatory microenvironment.

Rodent Animal Models of Endometriosis-Associated Pain: Unmet Needs and Resources Available for Improving Translational Research in Endometriosis

Chronic pain induced by endometriosis is a maladaptive pain experienced by half of women with this disease. The lack of pharmacological treatments suitable for the long-term relief of endometriosis-associated pain, without an impact on fertility, remains an urgent unmet need. Progress has been slowed by the absence of a reproducible rodent endometriosis model that fully replicates human physiopathological characteristics, including pain symptoms. Although pain assessment in rodents is a complicated task requiring qualified researchers, the choice of the behavioral test is no less important, since selecting inappropriate tests can cause erroneous data. Pain is usually measured with reflex tests in which hypersensitivity is evaluated by applying a noxious stimulus, yet this ignores the associated emotional component that could be evaluated via non-reflex tests. We conducted a systematic review of endometriosis models used in rodents and the number of them that studied pain. The type of behavioral test used was also analyzed and classified according to reflex and non-reflex tests. Finally, we determined the most used reflex tests for the study of endometriosis-induced pain and the main non-reflex behavioral tests utilized in visceral pain that can be extrapolated to the study of endometriosis and complement traditional reflex tests.

Exploratory Study of Serum Lactoferrin and Anti-Lactoferrin Antibody Concentrations in Patients with Endometriosis

Endometriosis is a disease that is characterized by the ectopic presence of the endometrium or its similar cells. A high prevalence of patients with autoimmune diseases has been reported among patients with endometriosis although the cause of endometriosis remained unknown. Recently, the anti-lactoferrin antibody is reported to be highly detected in autoimmune diseases. This study focused on lactoferrin and anti-lactoferrin antibodies to explore the pathology of endometriosis. Lactoferrin is a substance that regulates inflammation and is produced by neutrophils. Anti-lactoferrin antibody is a type of perinuclear antineutrophil cytoplasmic antibody. The serum lactoferrin and anti-lactoferrin antibody levels were compared among patients with or without endometriosis, revealing significantly higher levels in patients with endometriosis. Additionally, a decreased serum anti-lactoferrin antibody level was observed after surgical endometriosis resection. The receiver operating characteristic curve analysis determined the reference values for the serum lactoferrin and anti-lactoferrin antibody levels. Patients whose serum level exceeded the reference anti-lactoferrin antibody value were significantly higher in more than 40% of cases in the endometriosis group. The rate is comparable to that of autoimmune diseases. This is the first report that anti-lactoferrin antibody is frequently observed in patients with endometriosis, adding a new perspective to the understanding of the pathology of endometriosis although precisely elucidating the mechanism by which lactoferrin and anti-lactoferrin antibody appear in endometriosis in the future is necessary.

Association between dietary inflammatory index and risk of endometriosis: A population-based analysis

Background and aims

Chronic inflammation plays a significant role in the etiology of endometriosis, which might be affected by dietary intake. This study aimed to investigate the association between dietary inflammatory index (DII) and the risk of endometriosis.

Methods

A cross-sectional analysis using data from the National Health and Nutrition Examination Survey (1999-2006) was conducted on 3,410 American participants, among whom 265 reported a diagnosis of endometriosis. DII scores were calculated based on the dietary questionnaire. The association of DII scores with endometriosis was evaluated by adjusted multivariate logistic regression analyzes, which were further investigated in the subgroups.

Results

In the fully adjusted models, the odds ratio (OR) for endometriosis participants in the highest and middle tertiles of DII scores were 1.57 [95% confidence interval (CI): 1.14-2.17] and 1.18 (95% CI: 0.84-1.65), compared to the lowest tertile (P _trend = 0.007). In subgroup analyzes, the significant positive association between DII scores and the endometriosis risk was also observed in non-obese women (OR_tertile3vs1: 1.69, 95% CI: 1.12-2.55; P _trend = 0.012), women without diabetes (OR_tertile3vs1: 1.62, 95% CI: 1.16-2.27; P _trend = 0.005), women with hypertension (OR_tertile3vs1: 2.25, 95% CI: 1.31-3.87; P _trend = 0.003), parous women (OR_tertile3vs1: 1.55, 95% CI: 1.11-2.17; P _trend = 0.011), and women using oral contraceptives (OR_tertile3vs1: 1.63, 95% CI: 1.15-2.30; P _trend = 0.006).

Conclusion

This nationally representative study found that increased intake of the pro-inflammatory diet, as a higher DII score, was positively associated with endometriosis risk among American adults. Our results suggested anti-inflammatory dietary interventions may be promising in the prevention of endometriosis. Further prospective studies are necessary to confirm these findings.

Identification and Validation of Three m6A Regulators: FTO, HNRNPC, and HNRNPA2B1 as Potential Biomarkers for Endometriosis

BACKGROUND

N6-methyladenosine is involved in numerous biological processes. However, the significance of m6A regulators in endometriosis is still unclear.

METHODS

We extracted three significant m6A regulators between non-endometriosis and endometriosis patients from GSE6364 and then we used the random forest model to obtain significant m6A regulators. In addition, we used the nomogram model to evaluate the prevalence of endometriosis. The predictive ability of the candidate genes was evaluated through the receiver operating characteristic curves, while the expression of candidate biomarkers was validated via Western blotting. Additionally, according to candidate genes, we identified m6A subtypes based on which functional enrichment analysis and immune infiltration were performed.

RESULTS

Three significant m6A regulators (fat mass and obesity-associated protein, heterogeneous nuclear ribonucleoprotein A2/B1, and heterogeneous nuclear ribonucleoprotein C) were discovered. We identified three m6A subtypes, including clusterA, clusterB, and clusterC. ClusterB was demonstrated to be correlated with significantly overexpressed VEGF and notably downregulated ESR1 and PGR, which are convincing biomarkers of endometriosis. Furthermore, we discovered that patients in clusterB were associated with high levels of neutrophil infiltration, a reduced Treg/Th17 ratio, and overexpressed pyroptosis-related genes, which also indicated that clusterB was highly linked to endometriosis.

CONCLUSION

In conclusion, m6A regulators are of great significance for the occurrence and process of endometriosis. The findings of our study provide novel insights into the underlying molecular mechanism of endometriosis. The novel investigation of m6A patterns and their correlation with immunity may also help to guide the clinical diagnosis, provide prognostic significance, and develop immunotherapy strategies for endometriosis patients.

Aged garlic extract as a potential prophylactic to reduce the progression of endometriosis and associated pain burden

Endometriosis is a complex and potentially debilitating condition that has major impact on quality of life. There is emerging evidence that biological compounds found in garlic (Allium sativum) may be effective for attenuating endometrial pain. Suggested mechanisms for efficacy include modulation of inflammation and potent antioxidant effects. Aged-garlic-extract (AGE) is a centuries old process describing ethanolic extracts of garlic bulbs for 12-20 months. The AGE formulation realised contains a complex array of stabilised biologics with significant immunomodulatory effects relevant to inflammatory conditions. This perspective article puts forward a hypothesis that AGE should be considered as a prophylactic to manage endometrial pain.

A Computational Approach to Identification of Candidate Biomarkers in High-Dimensional Molecular Data

Complex high-dimensional datasets that are challenging to analyze are frequently produced through ‘-omics’ profiling. Typically, these datasets contain more genomic features than samples, limiting the use of multivariable statistical and machine learning-based approaches to analysis. Therefore, effective alternative approaches are urgently needed to identify features-of-interest in ‘-omics’ data. In this study, we present the molecular feature selection tool, a novel, ensemble-based, feature selection application for identifying candidate biomarkers in ‘-omics’ data. As proof-of-principle, we applied the molecular feature selection tool to identify a small set of immune-related genes as potential biomarkers of three prostate adenocarcinoma subtypes. Furthermore, we tested the selected genes in a model to classify the three subtypes and compared the results to models built using all genes and all differentially expressed genes. Genes identified with the molecular feature selection tool performed better than the other models in this study in all comparison metrics: accuracy, precision, recall, and F1-score using a significantly smaller set of genes. In addition, we developed a simple graphical user interface for the molecular feature selection tool, which is available for free download. This user-friendly interface is a valuable tool for the identification of potential biomarkers in gene expression datasets and is an asset for biomarker discovery studies.

Estrogen mediates inflammatory role of mast cells in endometriosis pathophysiology

Endometriosis is an estrogen dependent, chronic inflammatory disease characterized by the growth of endometrial lining outside of the uterus. Mast cells have emerged as key players in regulating not only allergic responses but also other mechanisms such as angiogenesis, fibrosis, and pain. The influence of estrogen on mast cell function has also been recognized as a potential factor driving disease pathophysiology in number of allergic and chronic inflammatory conditions. However, precise information is lacking on the cross talk between endocrine and immune factors within the endometriotic lesions and whether that contributes to the involvement of mast cells with disease pathophysiology. In this study, we observed a significant increase in mast cell numbers within endometriotic lesions compared to matched eutopic endometrium from the same patients. Compared to eutopic endometrium, endometriotic lesions had significantly higher levels of stem cell factor (SCF), a potent growth factor critical for mast cell expansion, differentiation, and survival for tissue resident mast cells. Targeted mRNA Q-PCR array revealed that the endometriotic lesions harbour microenvironment (upregulation of CPA3, VCAM1, CCL2, CMA1, CCR1, and KITLG) that is conducive to mast cells recruitment and subsequent differentiation. To examine cross-talk of mast cells within the endometriotic lesion microenvironment, endometriotic epithelial cells (12Z) and endometrial stromal cells (hESC) incubated with mast cell-conditioned media showed significantly increased production of pro-inflammatory and chemokinetic cytokines. To further understand the impact of estrogen on mast cells in endometriosis, we induced endometriosis in C57BL/6 mice. Mature mast cells were significantly higher in peritoneal fluid of estrogen-treated mice compared to untreated mice within the sham operated groups. Mouse endometriotic lesion tissue revealed several genes (qRT-PCR) relevant in mast cell biology significantly upregulated in the estrogen treated, endometriosis-induced group compared to control endometrium. The endometriotic lesions from estrogen treated mice also had significantly higher density of Alcian blue stained mast cells compared to untreated lesions or control endometrium. Collectively, these findings suggest that endometriotic lesions provide a microenvironment necessary for recruitment and differentiation of mast cells. In turn, mast cells potentially release pro-inflammatory mediators that contribute to chronic pelvic pain and endometriosis disease progression.

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

ABSTRACT

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

EGCG exposure during pregnancy affects uterine histomorphology in F1 female mice and the underlying mechanisms

Although epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, has been shown to have many benefits, the effect of EGCG exposure in utero on adult uterine development is unclear. In this study, pregnant C57BL/6 mice were exposed to 1 mg/kg body weight (bw) EGCG dissolved in drinking water from gestational days 0.5-16.5. A significant decrease in uterine weight was observed in the adult female mice, accompanied by uterine atrophy, inflammation, and fibrosis in the endometrium. Uterine atrophy was attributed to the thinning of the endometrial stromal layer and a significant reduction in endometrial cell proliferation. The expression levels of related proteins in the NF-κB and RAF/MEK/ERK signaling pathways were significantly increased, which might be responsible for the occurrence of inflammation. Activation of the transforming growth factor beta (TGF-β1)/Smad signaling pathway might be involved in the development of endometrial fibrosis. The changes in the expression of estrogen receptor α, β (ERα, ERβ), progesterone receptor (PGR), and androgen receptor (AR) might lead to changes in the aforementioned signaling pathways. The promoter region methylation level of Esr2 was increased, and the expression of DNMT3A was evaluated. Our study indicates a risk of EGCG intake during pregnancy affecting uterine development in offspring.

Endometriosis: A Disease with Few Direct Treatment Options

Endometriosis is a gynecological condition characterized by the growth of endometrium-like tissues inside and outside the pelvic cavity. The evolution of the disease can lead to infertility in addition to high treatment costs. Currently, available medications are only effective in treating endometriosis-related pain; however, it is not a targeted treatment. The objective of this work is to review the characteristics of the disease, the diagnostic means and treatments available, as well as to discuss new therapeutic options.

Immunopathogenesis of endometriosis: An overview of the role of innate and adaptive immune cells and their mediators

BACKGROUND

Endometriosis is a chronic inflammatory disease associated with the growth and proliferation of endometrial-like tissues outside the uterus. Although the exact etiology and mechanism of the pathogenesis of the disease have not been fully elucidated, the immune system cells and the mediators produced by them can be named as effective factors in the onset and progression of the disease.

AIMS

We aim to attempt to review studies on the role of the immune system in endometriosis to better understand the pathogenesis of endometriosis.

CONTENT

Abundant production of inflammatory mediators by neutrophils and macrophages and reduced cytotoxicity of defined cells promote endometriosis at the early stages of the disease. Following an increase in the inflammation of the environment, the body takes compensatory mechanisms to reduce inflammation and establish homeostasis. For this purpose, the body produces remodeling and anti-inflammatory factors leading to slow conversion of the inflammatory environment into a non-inflammatory environment with proliferative and immunosuppressive properties. Environmental conditions induce M2 macrophages, TH2 cells, and Tregs differentiation, promoting disease progression by producing angiogenic and immunosuppressive factors. However, the exact molecular mechanism involved in changing inflammatory to non-inflammatory conditions is not yet fully understood.

IMPLICATIONS

Due to the common characteristics of endometriotic cells and cancer cells, most potential treatment options for endometriosis have been suggested due to the results of these methods in the treatment of cancer. In this pathway, immune system cells and soluble mediators can be used as targets.

Inhibition of Neutrophil Extracellular Traps Formation by Cl-Amidine Alleviates Lipopolysaccharide-Induced Endometritis and Uterine Tissue Damage

Endometritis is a common disease that affects the production in dairy cows and leads to severe losses in the dairy industry. Neutrophil extracellular traps (NETs) formation promotes pathogenic invasions of the lumen of the tissue, leading to inflammatory diseases such as mastitis, pancreatitis, and septic infection. However, research that could show the relationship between NETs and endometritis is scarce. Cl-amidine has been shown to ameliorate the disease squealing and clinical manifestation in various disease models. In this study, we investigated the role of NETs in LPS-triggered endometritis in rats and evaluated the therapeutic efficiency of Cl-amidine. An LPS-induced endometritis model in rats was established and found that the formation of NETs can be detected in the rat's uterine tissues in vivo. In addition, Cl-amidine treatment can inhibit NETs construction in LPS-induced endometritis in rats. Myeloperoxidase (MPO) activity assay indicated that Cl-amidine treatment remarkably alleviated the inflammatory cell infiltrations and attenuated the damage to the uterine tissue. The Western blot results indicated that Cl-amidine decreased the expression of citrullinated Histone H3 (Cit-H3) and high-mobility group box 1 protein (HMGB1) protein in LPS-induced rat endometritis. The ELISA test indicated that Cl-amidine treatment significantly inhibited the expression of the pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. The NETs were determined by Quant-iTTMPicoGreen dsDNA kit®, which indicated that Cl-amidine significantly inhibited the NETs in rat serum. All results showed that Cl-amidine effectively reduced the expression of Cit-H3 and HMGB1 proteins by inhibiting the formation of NETs, thereby attenuating the inflammatory response to LPS-induced endometritis in rats. Hence, Cl-amidine could be a potential candidate for the treatment of endometritis.

Local Innate Markers and Vaginal Microbiota Composition Are Influenced by Hormonal Cycle Phases

Background

The female reproductive tract (FRT) mucosa is the first line of defense against sexually transmitted infection (STI). FRT environmental factors, including immune-cell composition and the vaginal microbiota, interact with each other to modulate susceptibility to STIs. Moreover, the menstrual cycle induces important modifications within the FRT mucosa. Cynomolgus macaques are used as a model for the pathogenesis and prophylaxis of STIs. In addition, their menstrual cycle and FRT morphology are similar to women. The cynomolgus macaque vaginal microbiota is highly diverse and similar to dysbiotic vaginal microbiota observed in women. However, the impact of the menstrual cycle on immune markers and the vaginal microbiota in female cynomolgus macaques is unknown. We conducted a longitudinal study covering three menstrual cycles in cynomolgus macaques. The evolution of the composition of the vaginal microbiota and inflammation (cytokine/chemokine profile and neutrophil phenotype) in the FRT and blood was determined throughout the menstrual cycle.

Results

Cervicovaginal cytokine/chemokine concentrations were affected by the menstrual cycle, with a peak of production during menstruation. We observed three main cervicovaginal neutrophil subpopulations: CD11b^high CD101⁺ CD10⁺ CD32a⁺, CD11b^high CD101⁺ CD10^- CD32a⁺, and CD11b^low CD101^low CD10^- CD32a^-, of which the proportion varied during the menstrual cycle. During menstruation, there was an increase in the CD11b^high CD101⁺ CD10⁺ CD32a⁺ subset of neutrophils, which expressed higher levels of CD62L. Various bacterial taxa in the vaginal microbiota showed differential abundance depending on the phase of the menstrual cycle. Compilation of the factors that vary according to hormonal phase showed the clustering of samples collected during menstruation, characterized by a high concentration of cytokines and an elevated abundance of the CD11b^high CD101⁺ CD10⁺ CD32a⁺ CD62L⁺ neutrophil subpopulation.

Conclusions

We show a significant impact of menstruation on the local environment (cytokine production, neutrophil phenotype, and vaginal microbiota composition) in female cynomolgus macaques. Menstruation triggers increased production of cytokines, shift of the vaginal microbiota composition and the recruitment of mature/activated neutrophils from the blood to the FRT. These results support the need to monitor the menstrual cycle and a longitudinal sampling schedule for further studies in female animals and/or women focusing on the mucosal FRT environment.

The ischemic time window of ectopic endometrial tissue crucially determines its ability to develop into endometriotic lesions

Endometriosis develop from shed endometrial fragments via retrograde menstruation. This affects the survival, proliferation and vascularization of the tissue and its final ability to form endometriotic lesions. Within this study, uterine tissue samples from donor mice were precultivated for 24 h or 72 h to simulate avascular periods. Their morphology, microvessel density, apoptotic activity and expression of angiogenesis-related proteins were analyzed in vitro. The formation of endometriotic lesions in vivo was assessed after transplantation of precultivated uterine tissue samples to the abdominal wall and dorsal skinfold chambers by means of high-resolution ultrasound, intravital fluorescence microscopy, histology and immunohistochemistry. In vitro, 72-h-precultivated uterine tissue samples exhibit extensive areas of tissue necrosis and high numbers of apoptotic cells as well as a significantly reduced cell and microvessel density. These samples failed to develop into endometriotic lesions. In contrast, the 24-h-precultivated samples showed, that their early vascularization and growth in vivo was improved when compared to controls. This indicates that avascular periods have a strong impact on the survival of ectopic endometrial tissue and the chance for the development of endometriosis.

Genomic Evidence Supports the Recognition of Endometriosis as an Inflammatory Systemic Disease and Reveals Disease-Specific Therapeutic Potentials of Targeting Neutrophil Degranulation

Background

Endometriosis, classically viewed as a localized disease, is increasingly recognized as a systemic disease with multi-organ effects. This disease is highlighted by systemic inflammation in affected organs and by high comorbidity with immune-mediated diseases.

Results

We provide genomic evidence to support the recognition of endometriosis as an inflammatory systemic disease. This was achieved through our genomics-led target prioritization, called ‘END’, that leverages the value of multi-layered genomic datasets (including genome-wide associations in disease, regulatory genomics, and protein interactome). Our prioritization recovered existing proof-of-concept therapeutic targeting in endometriosis and outperformed competing prioritization approaches (Open Targets and Naïve prioritization). Target genes at the leading prioritization revealed molecular hallmarks (and possibly the cellular basis as well) that are consistent with systemic disease manifestations. Pathway crosstalk-based attack analysis identified the critical gene AKT1. In the context of this gene, we further identified genes that are already targeted by licensed medications in other diseases, such as ESR1. Such analysis was supported by current interests targeting the PI3K/AKT/mTOR pathway in endometriosis and by the fact that therapeutic agents targeting ESR1 are now under active clinical trials in disease. The construction of cross-disease prioritization map enabled the identification of shared and distinct targets between endometriosis and immune-mediated diseases. Shared target genes identified opportunities for repurposing existing immunomodulators, particularly disease-modifying anti-rheumatic drugs (such as TNF, IL6 and IL6R blockades, and JAK inhibitors). Genes highly prioritized only in endometriosis revealed disease-specific therapeutic potentials of targeting neutrophil degranulation – the exocytosis that can facilitate metastasis-like spread to distant organs causing inflammatory-like microenvironments.

Conclusion

Improved target prioritization, along with an atlas of in silico predicted targets and repurposed drugs (available at https://23verse.github.io/end), provides genomic insights into endometriosis, reveals disease-specific therapeutic potentials, and expands the existing theories on the origin of disease.

Current Challenges in the Management of Chronic Pelvic Pain in Women: From Bench to Bedside

Chronic pelvic pain (CPP) affects a significant proportion of women worldwide And has a negative impact on several aspects of these women’s lives including mental health, work, relationships and sexual function, among others. This set of factors ultimately reflects negatively on quality Of life. The physiopathology of CPP is complex and remains to be fully clarified; however, recent advances have increased understanding of the mechanisms involved in chronic pain in general, and more specifically, CPP. Nonetheless, even when a detailed clinical history is obtained, meticulous physical examination is performed and imaging resources are appropriately used, the organic cause of the pain may still fail to be identified in a substantial number of women with CPP. Management of CPP may therefore be challenging. This narrative review was aimed at adding to the available literature on the subject, presenting and discussing the principal characteristics of CPP in women. The paper highlights gaps in the literature while providing the most up-to-date evidence associated with the physiopathology and classification of pain, its diagnosis and treatment. In addition, current challenges in the management of women with CPP are discussed.

Endometriosis in the Mouse: Challenges and Progress Toward a ‘Best Fit’ Murine Model

Endometriosis is a prevalent gynecologic condition associated with pelvic pain and infertility characterized by the implantation and growth of endometrial tissue displaced into the pelvis via retrograde menstruation. The mouse is a molecularly well-annotated and cost-efficient species for modeling human disease in the therapeutic discovery pipeline. However, as a non-menstrual species with a closed tubo-ovarian junction, the mouse poses inherent challenges as a preclinical model for endometriosis research. Over the past three decades, numerous murine models of endometriosis have been described with varying degrees of fidelity in recapitulating the essential pathophysiologic features of the human disease. We conducted a search of the peer-reviewed literature to identify publications describing preclinical research using a murine model of endometriosis. Each model was reviewed according to a panel of ideal model parameters founded on the current understanding of endometriosis pathophysiology. Evaluated parameters included method of transplantation, cycle phase and type of tissue transplanted, recipient immune/ovarian status, iterative schedule of transplantation, and option for longitudinal lesion assessment. Though challenges remain, more recent models have incorporated innovative technical approaches such as in vivo fluorescence imaging and novel hormonal preparations to overcome the unique challenges posed by murine anatomy and physiology. These models offer significant advantages in lesion development and readout toward a high-fidelity mouse model for translational research in endometriosis.

Identification of Candidate Gene Signatures and Regulatory Networks in Endometriosis and its Related Infertility by Integrated Analysis

Endometriosis is a common gynecological disease associated with infertility, and it represents an economic burden worldwide. However, the molecular mechanisms underlying endometriosis development have not yet been fully elucidated. Here, we aimed to identify reliable key genes and the related regulatory network that may be involved in endometriosis. Differentially expressed genes (DEGs) were identified through integrated analysis of four expression datasets of endometriosis from Gene Expression Omnibus. Gene functional analysis and protein-protein interaction network construction were performed to reveal the potential function of DEGs. Subsequently, candidate hub genes were defined and validated in GSE105764 dataset, and the associated regulatory networks were constructed. Additionally, GSE120103 dataset was applied to identify the differential expression between the infertile and fertile groups of patients with stage IV endometriosis. Finally, real-time quantitative polymerase chain reaction analysis was performed to identify the differential expression of hub genes in the collected clinical specimens. Robust rank aggregation integrated analysis determined 158 DEGs. Epithelial cell differentiation was the most significantly enriched biological process, and leukocyte transendothelial migration was the most significantly enriched pathway. Eight hub genes including CLDN3, CLDN5, CLDN7, CLDN11, HOXC8, HOXC6, HOXB6, and HOXB7 were identified, and most of these were validated as abnormally expressed genes in both the infertile group and patients with endometriosis. Transcriptional factors and microRNAs related to these genes were identified. Altogether, our integrated analysis identified critical gene signatures, involved pathways, and regulatory networks, which could provide clinically significant insights into the molecular mechanisms underlying endometriosis and its related infertility.

G-CSF and IL-6 may be involved in formation of endometriosis lesions by increasing the expression of angiogenic factors in neutrophils

Evidence accumulated in recent years has revealed that neutrophils are involved in the initial establishment of endometriosis, which is well-known as a chronic inflammatory disease. So far, why and how neutrophils promote the formation of early endometriosis are still unclear. In this study, using a mouse model of endometriosis, we demonstrated that endometriosis mice (EMs mice) had a significantly increased number of neutrophils in peritoneal fluids and lesions, and increased levels of granulocyte colony-stimulating factor (G-CSF) and IL-6 in serum and peritoneal fluids compared to the control group. In the neutrophils and uterine fragments co-injection experiment, neutrophils regulated by G-CSF and IL-6 had a similar effect to neutrophils from EMs mice, increasing the number, area, weight and microvessel density (MVD) of endometriotic lesions. Blocking the effect of G-CSF and IL-6 in EMs mice resulted in a decrease in the number, area and weight of endometriotic lesions. Following the depletion of neutrophils in vivo using a anti-Ly6G antibody, the MVD in the lesions of mice treated with neutrophils from EMs mice and neutrophils from pG/pI6 mice were significantly reduced. Neutrophils from EMs mice and neutrophils from pG/pI6 mice altered the expression levels of Mmp9, Bv8 and Trail genes compared to the neutrophils from PBS-treated mice. IL-6 together with G-CSF induced a higher expression of phospho-STAT3 and STAT3 in neutrophils. These findings suggest that neutrophils modulated by G-CSF and IL-6 through the STAT3 pathway alter the expression levels of the angiogenesis-related genes Mmp9, Bv8 and Trail, and may promote the establishment of early endometriosis.

Implications of dysregulated endogenous cannabinoid family members in the pathophysiology of endometriosis

OBJECTIVE

To determine the involvement of the endocannabinoid (EC) family member in the pathophysiology of endometriosis (EMS).

DESIGN

Mass spectrometry analysis of plasma and tissue samples from patients with EMS, controls, and a mouse model of EMS and messenger RNA and immunohistochemistry analysis of the samples from patients with EMS and controls.

SETTING

Academic teaching hospital and university.

PATIENT(S)

Patients with EMS and healthy fertile control subjects.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Endocannabinoid analysis in patient plasma, EMS lesions, and healthy endometrial samples.

RESULT(S)

Circulating ECs were detected in the plasma samples, whereas no significant changes were observed in patients with EMS compared with healthy fertile controls. However, the palmitoylethanolamide levels were significantly higher in the EMS lesions than in the endometrium from patients with EMS. Similarly, genes involved in the EC signaling pathways were differentially expressed in the EMS lesions. Analysis of cannabinoid 1 and 2 receptors in the EMS lesions revealed a significantly lower cannabinoid 2 receptor expression, whereas no significant changes were observed in cannabinoid 1 receptor expression compared with those in the endometrium from both patients with EMS and healthy fertile controls. The palmitoylethanolamide levels were significantly elevated in plasma from EMS mice compared with that from sham controls and in EMS lesions compared with uterine samples.

CONCLUSION(S)

Together, we provide evidence toward dysregulation of members of the ECs in both patients with EMS and the mouse model of EMS. These findings will advance the knowledge of the role of ECs in EMS and their potential implications as therapeutic targets.

Immunoregulation by type I interferons in the peritoneal cavity

The peritoneal cavity, a fluid-containing potential space surrounding the abdominal and pelvic organs, is home to a rich network of immune cells that maintain tissue homeostasis and provide protection against infection. However, under pathological conditions such as peritonitis, endometriosis, and peritoneal carcinomatosis, the peritoneal immune system can become dysregulated, resulting in nonresolving inflammation and disease progression. An enhanced understanding of the factors that regulate peritoneal immune cells under both homeostatic conditions and in disease contexts is therefore required to identify new treatment strategies for these often life-limiting peritoneal pathologies. Type I interferons (T1IFNs) are a family of cytokines with broad immunoregulatory functions, which provide defense against viruses, bacteria, and cancer. There have been numerous reports of immunoregulation by T1IFNs within the peritoneal cavity, which can contribute to both the resolution or propagation of peritoneal disease states, depending on the specifics of the disease setting and local environment. In this review, we provide an overview of the major immune cell populations that reside in the peritoneal cavity (or infiltrate it under inflammatory conditions) and highlight their contribution to the initiation, progression, or resolution of peritoneal diseases. Additionally, we will discuss the role of T1IFNs in the regulation of peritoneal immune cells, and summarize the results of laboratory studies and clinical trials which have investigated T1IFNs in peritonitis/sepsis, endometriosis, and peritoneal carcinomatosis.

Exosomes and their cargo are important regulators of cell function in endometriosis

Endometriosis is a chronic oestrogen-dependent gynaecological disorder characterized by non-menstrual pelvic pain, infertility and the extrauterine growth of endometrial-like glands and stroma. It has been noted that the eutopic endometrium of women with endometriosis is functionally distinct from that of women without endometriosis. Moreover, ectopic endometrial implants are functionally different from the eutopic endometrium of women with endometriosis. However, the mechanisms directing these differences are ill-defined. It is proposed here that small membrane-bound extracellular vesicles called exosomes are important vehicles in the protection and transport of signalling molecules central to the dysregulation of endometrial function in women with endometriosis. Therefore, a critical review of the literature linking exosomes and their cargo to the pathobiology of endometriosis was conducted. Circulating peritoneal fluid and endometrial cell exosomes contained long non-coding RNA, miRNA and proteins involved in histone modification, angiogenesis and immune modulation that differed significantly in women with endometriosis compared with controls. Moreover, experimental evidence supports a role for exosomes and their cargo in angiogenesis, neurogenesis, immune modulation and endometrial stromal cell invasion. It is therefore suggested that exosomes play an important role in the pathophysiology of endometriosis.

Endometriosis and the Fallopian Tubes: Theories of Origin and Clinical Implications

Endometriosis is a common, oestrogen driven chronic condition, where endometrium-like epithelial and stromal cells exist in ectopic sites. At present, no curative treatments are available and the existing evidence for disease progression is conflicting. The pathogenesis is still unknown and evidently complex, as mechanisms of initiation may depend on the anatomical distribution of endometriotic lesions. However, amongst the numerous theories and plethora of mechanisms, contributions of the fallopian tubes (FT) to endometriosis are rarely discussed. The FT are implicated in all endometriosis associated symptomatology and clinical consequences; they may contribute to the origin of endometriotic tissue, determine the sites for ectopic lesion establishment and act as conduits for the spread of proinflammatory media. Here, we examine the available evidence for the contribution of the human FT to the origin, pathogenesis and symptoms/clinical consequences of endometriosis. We also examine the broader topic linking endometriosis and the FT epithelium to the genesis of ovarian epithelial cancers. Further studies elucidating the distinct functional and phenotypical characteristics of FT mucosa may allow the development of novel treatment strategies for endometriosis that are potentially curative.