Immunology of endometriosis

Immunomodulation in Endometriosis: Investigating the interrelationship between VISTA expression and Escherichia.Shigella-Associated metabolites

AIMS

Endometriosis is characterized by an abnormal immune microenvironment. Despite the extensive use of immune therapies, the application of immune checkpoint inhibitors in endometriosis lacks confidence due to the instability of preclinical research data. This study aims to elucidate the regulation of the immune inhibitory checkpoint VISTA and its effects on T cells from the perspective of microbiota and metabolism.

MAIN METHODS

We divided endometriosis patients into high and low groups based on the expression levels of VISTA in lesion tissues. We collected peritoneal fluid samples from these two groups and performed 16 s RNA sequencing and metabolomics analysis to investigate microbial diversity and differential metabolites. Through combined analysis, we identified microbial-associated metabolites and validated their correlation with VISTA and CD8 + T cells using ELISA and immunofluorescence. In vitro experiments were conducted to confirm the regulatory relationship among these factors.

KEY FINDINGS

Our findings revealed a distinct correlation between VISTA expression and the microbial colony Escherichia.Shigella. Moreover, we identified the metabolites LTD4-d5 and 2-n-Propylthiazolidine-4-carboxylic acid as being associated with both Escherichia.Shigella and VISTA expression. In vitro experiments confirmed the inhibitory effects of these metabolites on VISTA expression, while they demonstrated a positive regulation of CD8 + T cell infiltration into endometriotic lesions.

SIGNIFICANCE

This study reveals the connection between microbial diversity, metabolites, and VISTA expression in the immune microenvironment of endometriosis, providing potential targets for therapeutic interventions.

MCP-1 exerts the inflammatory response via ILK activation during endometriosis pathogenesis

AIMS

MCP-1 has been shown to be elevated in endometriosis. ILK functions in several cellular events and interacts with MCP-1-signaling. In the current study, we evaluated the role of MCP-1-ILK signaling in human endometriotic cell's (Hs832(C).TCs) potential for colonization, invasion, adhesion, etc. and differentiation of macrophage along with inflammation in an endometriosis mouse model.

MATERIALS AND METHODS

A mouse model of endometriosis with elevated levels of MCP-1 was developed by injecting MCP-1. We examined the migration, adhesion, colonization and invasion of Hs832(C).TCs in response to MCP-1-ILK signaling. We also examined the differentiation of THP-1 cells to macrophage in response to MCP-1-ILK signaling.

KEY FINDINGS

We observed that MCP-1 increased Ser246 phosphorylation of ILK in Hs832(C).TCs and enhanced the migration, adhesion, colonization, and invasion of Hs832(C).TCs. In the mouse model of endometriosis, we found elevated chemokines (CCL-11, CCL-22 and CXCL13) levels. An increased level of MCP-1 mediated ILK activation, leading to increased inflammatory reaction and infiltration of residential and circulatory macrophages, and monocyte differentiation, but suppressed the anti-inflammatory reaction. The inhibitor (CPD22) of ILK reversed the MCP-1-mediated action by restoring Hs832(C).TCs and THP-1 phenotype. ILK inhibition in a mouse model of endometriosis reduced the effects of MCP-1 mediated pro-inflammatory cytokines, but increased anti-inflammatory response along with T-regulatory and T-helper cell restoration.

SIGNIFICANCE

Targeting ILK restores MCP-1 milieu in the peritoneal cavity and endometrial tissues, reduces the inflammatory response, improves the T-regulatory and T-helper cells in the endometriosis mouse model and decreases the migration, adhesion, colonization and invasion of endometriotic cells.

Recent Advances in Endometriosis Pathophysiology and Pharmacological Treatment

Endometriosis, affecting an estimated 10% of women of reproductive age [...].

Effects of the gut microbiota and its metabolite short-chain fatty acids on endometriosis

In recent years, a growing body of research has confirmed that the gut microbiota plays a major role in the maintenance of human health and disease. A gut microbiota imbalance can lead to the development of many diseases, such as pregnancy complications, adverse pregnancy outcomes, polycystic ovary syndrome, endometriosis, and cancer. Short-chain fatty acids are metabolites of specific intestinal bacteria and are crucial for maintaining intestinal homeostasis and regulating metabolism and immunity. Endometriosis is the result of cell proliferation, escape from immune surveillance, and invasive metastasis. There is a strong correlation between the anti-proliferative and anti-inflammatory effects of short-chain fatty acids produced by gut microbes and the development of endometriosis. Given that the mechanism of action of gut microbiota and Short-chain fatty acids in endometriosis remain unclear, this paper aims to provide a comprehensive review of the complex interactions between intestinal flora, short-chain fatty acids and endometriosis. In addition, we explored potential microbial-based treatment strategies for endometriosis, providing new insights into the future development of diagnostic tests and prevention and treatment methods for endometriosis.

Endometriosis-associated ovarian cancer: a different clinical entity

OBJECTIVE

To compare survival outcomes and patterns of recurrence between endometriosis-associated ovarian cancer patients and non-endometriosis-associated ovarian cancer patients.

METHODS

This retrospective study included data of consecutive patients with endometrioid or clear cell ovarian cancer treated at the Fondazione IRCCS Istituto Nazionale dei Tumori di Milano between January 2010 and June 2021. Patients were assigned to one of two groups according to the absence or presence of endometriosis together with ovarian cancer at final histological examination. Survival outcomes were assessed using Kaplan-Meier and Cox hazard models. Proportions in recurrence rate and pattern of recurrence were evaluated using the Fisher exact test.

RESULTS

Overall, 83 women were included in the endometriosis-associated ovarian cancer group and 144 in the non-endometriosis-associated ovarian cancer group, respectively. Patients included in the non- endometriosis-associated ovarian cancer group had a shorter disease-free survival than those in the endometriosis-associated ovarian cancer group (23.4 (range 2.0-168.9) vs 60.9 (range 4.0-287.8) months; p<0.001). Univariable and multivariable analyses showed that the association with endometriosis, previous hormonal treatment, early stage at presentation, and endometrioid histology were related to better disease-free survival in the entire study population. Similarly, patients in the non-endometriosis-associated ovarian cancer group had a shorter median (range) overall survival than those in the endometriosis-associated ovarian cancer group (54.4 (range 0.7-190.6) vs 77.6 (range 4.5-317.8) months; p<0.001). Univariable and multivariable analyses showed that younger age at diagnosis, association with endometriosis, and early stage at presentation were related to better overall survival. The recurrence rate was higher in the non-endometriosis-associated ovarian cancer group (63/144 women, 43.8%) than in the endometriosis-associated ovarian cancer group (17/83 women, 20.5%; p<0.001).

CONCLUSIONS

Endometriosis-associated ovarian cancer patients had significantly longer disease-free survival and overall survival than non-endometriosis-associated ovarian cancer patients, while the recurrence rate was higher in non-endometriosis-associated ovarian cancer patients.

Heme metabolism and HO-1 in the pathogenesis and potential intervention of endometriosis

Endometriosis (EM) is one of the diseases related to retrograded menstruation and hemoglobin. Heme, released from hemoglobin, is degraded by heme oxygenase-1 (HO-1). In EM lesions, heme metabolites regulate processes such as inflammation, redox balance, autophagy, dysmenorrhea, malignancy, and invasion, where macrophages (Mø) play a fundamental role in their interactions. Regulation occurs at molecular, cellular, and pathological levels. Numerous studies suggest that heme is an indispensable component in EM and may contribute to its pathogenesis. The regulatory role of heme in EM encompasses cytokines, signaling pathways, and kinases that mediate cellular responses to external stimuli. HO-1, a catalytic enzyme in the catabolic phase of heme, mitigates heme's cytotoxicity in EM due to its antioxidant, anti-inflammatory, and anti-proliferative properties. Certain compounds may intervene in EM by targeting heme metabolism, guiding the development of appropriate treatments for all stages of endometriosis.

Immune pathway through endometriosis to ovarian cancer

Endometriosis is an estrogen-dependent inflammatory disease, defined by the presence of functional endometrial tissue outside of the uterine cavity. This disease is one of the main gynecological diseases, affecting around 10%-15% women and girls of reproductive age, being a common gynecologic disorder. Although endometriosis is a benign disease, it shares several characteristics with invasive cancer. Studies support that it has been linked with an increased chance of developing endometrial ovarian cancer, representing an earlier stage of neoplastic processes. This is particularly true for women with clear cell carcinoma, low-grade serous carcinoma and endometrioid. However, the carcinogenic pathways between both pathologies remain poorly understood. Current studies suggest a connection between endometriosis and endometriosis-associated ovarian cancers (EAOCs) via pathways associated with oxidative stress, inflammation, and hyperestrogenism. This article aims to review current data on the molecular events linked to the development of EAOCs from endometriosis, specifically focusing on the complex relationship between the immune response to endometriosis and cancer, including the molecular mechanisms and their ramifications. Examining recent developments in immunotherapy and their potential to boost the effectiveness of future treatments.

Pyroptotic T cell-derived active IL-16 has a driving function in ovarian endometriosis development

Endometriosis, affecting 6%-10% of women, often leads to pain and infertility and its underlying inflammatory mechanisms are poorly understood. We established endometriosis models in wild-type and IL16KO mice, revealing the driver function of IL-16 in initiating endometriosis-related inflammation. Using an in vitro system, we confirmed iron overload-induced GSDME-mediated pyroptosis as a key trigger for IL-16 activation and release. In addition, our research led to the development of Z30702029, a compound inhibiting GSDME-NTD-mediated pyroptosis, which shows promise as a therapeutic intervention for endometriosis. Importantly, our findings extend beyond endometriosis, highlighting GSDME-mediated pyroptosis as a broader pathway for IL-16 release and offering insights into potential treatments for various inflammatory conditions.

Platelet rich plasma alleviates endometritis induced by lipopolysaccharide in mice via inhibiting TLR4/NF-κB signaling pathway

BACKGROUND

Endometritis is an inflammatory reaction of the lining of uterus, leading to the occurrence of infertility. Platelet rich plasma (PRP) has been proven to exhibit extremely effective for the treatment of endometrium-associated infertility, but the mechanism of its prevention for endometritis remains unclear.

OBJECTIVE

The present study aimed to investigate the protective effect of PRP against endometritis induced by lipopolysaccharide (LPS) and elucidate the mechanism underlying these effects.

METHODS

Mouse model of endometritis was established by intrauterine perfusion of LPS. PRP intrauterine infusion was administered at 24 h after LPS induction. After another 24 h, the uterine tissues were harvested to observe histopathological changes, production of proinflammatory cytokines, variation of the Toll-like receptor 4/nuclear factor κB (TLR4/NF-κB) signaling pathways, and validated the anti-inflammatory effect of PRP. The myeloperoxidase (MPO) activity and concentration of nitric oxide (NO) were determined using assay kit. Proinflammatory chemokines (tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6)) were measured by ELISA and Real-Time PCR. The activity of TLR4/NF-κB pathway in uterine tissues was measured by Western blotting.

RESULTS

Hematoxylin-eosin staining (H&E) appeared that PRP remarkably relieved the impairment of uterine tissues. Detection of MPO activity and concentration of NO revealed that PRP treatment distinctly mitigated infiltration of inflammatory cells in mice with endometritis induced by LPS. PRP treatment significantly affected the expression of TNF-α, IL-1β, and IL-6. PRP was also found to suppress LPS-induced activation of TLR4/NF-κB pathway.

CONCLUSION

PRP effectively alleviates LPS-induced endometritis via restraining the signal pathway of TLR4/NF-κB. These findings provide a solid foundation for PRP as a potential therapeutic agent for endometritis.

Diet in Prevention and Treatment of Endometriosis: Current State of Knowledge

PURPOSE OF REVIEW

Endometriosis (EM) is a chronic gynecological disease that affects about 10% of women worldwide. It is characterized by the implantation of endometrial cells at ectopic sites. The most common symptom of EM is painful menstruation, which can often lead to chronic pelvic pain that significantly worsens the quality of life. Because some disease-related processes, such as inflammation, hormonal activity, menstrual cycle, or prostaglandin metabolism, can be modified by diet, nutrition may have a significant impact on development and treatment of EM. The purpose of this article was to overview the current knowledge regarding the dietary management of endometriosis.

RECENT FINDINGS

The attention of researchers has so far concentrated mainly on the role of nutrition in the risk of developing EM, while less attention has been paid to examining the use of diet in the treatment of the disease. Current studies focus primarily on various dietary components that have antiproliferative, anti-inflammatory, antioxidant, analgesic, and estrogen-lowering properties. Exploring different ways of coping with endometriosis can make a significant contribution to improving the quality of life of women at risk or diagnosed with EM.

New insights about endometriosis-associated ovarian cancer: pathogenesis, risk factors, prediction and diagnosis and treatment

Previous studies have shown that the risk of malignant transformation of endometriosis in premenopausal women is approximately 1%, significantly impacting the overall well-being and quality of life of affected women. Presently, the diagnostic gold standard for endometriosis-associated ovarian cancer (EAOC) continues to be invasive laparoscopy followed by histological examination. However, the application of this technique is limited due to its high cost, highlighting the importance of identifying a non-invasive diagnostic approach. Therefore, there is a critical need to explore non-invasive diagnostic methods to improve diagnostic precision and optimize clinical outcomes for patients. This review presents a comprehensive survey of the current progress in comprehending the pathogenesis of malignant transformation in endometriosis. Furthermore, it examines the most recent research discoveries concerning the diagnosis of EAOC and emphasizes potential targets for therapeutic intervention. The ultimate objective is to improve prevention, early detection, precise diagnosis, and treatment approaches, thereby optimizing the clinical outcomes for patients.

Pilot study of treatment of patients with deep infiltrative endometriosis with methotrexate carried in lipid nanoparticles

OBJECTIVE

Previously, lipid nanoparticles (LDE) injected in women with endometriosis were shown to concentrate in the lesions. Here, the safety and feasibility of LDE carrying methotrexate (MTX) to treat deep infiltrating endometriosis was tested.

DESIGN

Prospective pilot study.

SETTING

Perola Byington Hospital Reference for Women's Health.

SUBJECTS

Eleven volunteers (aged 30-47 years, BMI 26.15 ± 6.50 kg/m2) with endometriosis with visual analog scale pelvic pain scores (VAS) > 7 and rectosigmoid lesions were enrolled in the study.

INTERVENTION

Three patients were treated with LDE-MTX at single intravenous 25 mg/m2 dose of MTX and eight patients with two 25 mg/m2 doses with 1-week interval.

MAIN OUTCOME MEASURES

Clinical complaints, blood count, and biochemistry were analyzed before treatment and on days 90, 120, and 180 after LDE-MTX administration. Endometriotic lesions were evaluated by pelvic and transvaginal ultrasound (TVUS) before treatment and on days 30 and 180 after LDE-MTX administration.

RESULTS

No clinical complaints related with LDE-MTX treatment were reported by the patients, and no hematologic, renal, or hepatic toxicities were observed in the laboratorial exams. FSH, LH, TSH, free T4, anti-Müllerian hormone, and prolactin levels were also within normal ranges during the observation period. Scores for deep dyspareunia (p < 0.001), chronic pelvic pain (p = 0.008), and dyschezia (p = 0.025) were improved over the 180-day observation period. There was a non-significant trend for reduction of VAS scores for dysmenorrhea. Bowel lesions by TVUS were unchanged. No clear differences between the two dose levels in therapeutic responses were observed.

CONCLUSION

Results support the safety and feasibility of using LDE-MTX in women with deep infiltrating endometriosis as a novel and promising therapy for the disease. More prolonged treatment schemes should be tested in future placebo-controlled studies aiming to establish the usefulness of this novel nanomedicine approach.

Investigation of the Therapeutic Effect of Salbutamol on Endometriosis in a Mouse Model

Endometriosis is an immune chronic inflammatory disease, and there are currently no more effective drugs for treating endometriosis due to its unknown etiology. Salbutamol is a β2-adrenergic receptor (β2AR) agonist commonly used to treat asthma by selectively activating β2 receptors on airway smooth muscle and leukocytes, exerting bronchial dilation and synergistic anti-inflammatory effects. In recent years, β2AR agonists have been used in endometriosis studies, and we speculate that salbutamol may have a therapeutic effect on endometriosis. The purpose of this research was to explore the therapeutic effect of salbutamol on endometriosis mice. The mouse endometriosis model was established and treated with different doses of salbutamol. Endometrial lesions were harvested for pathological diagnosis, immunohistochemistry (IHC), Masson staining, and toluidine blue analysis. We found that the number and size of endometriotic lesions were all significantly decreased after 3 weeks of treatment with different doses of salbutamol on endometriosis model mice (P < 0.05). After Salbutamol treatment, the amount of mast cells (toluidine blue) and macrophages (F4/80) in the lesions as well as the expressions of interleukin (IL)-1β, tumor necrosis factor (TNF)-ɑ, platelet-derived growth factor subunit B (PDGFB), CD31, transforming growth factor (TGF)-β, Masson staining, BCL2, TUBB3, substance P (SP), and nerve growth factor (NGF) were significantly reduced (P < 0.05). These results suggested that salbutamol could effectively treat endometriosis in mice by reducing immune inflammatory cells and factors, angiogenesis, and fibrosis, increasing apoptosis of endometriotic lesions, and decreasing neurogenesis.

Crimson clues: advancing endometriosis detection and management with novel blood biomarkers

Endometriosis is an inflammatory condition affecting approximately 10% of the female-born population. Despite its prevalence, the lack of noninvasive biomarkers has contributed to an established global diagnostic delay. The intricate pathophysiology of this enigmatic disease may leave signatures in the blood, which, when detected, can be used as noninvasive biomarkers. This review provides an update on how investigators are utilizing the established disease pathways and innovative methodologies, including genome-wide association studies, next-generation sequencing, and machine learning, to unravel the clues left in the blood to develop blood biomarkers. Many blood biomarkers show promise in the discovery phase, but because of a lack of standardized and robust methodologies, they rarely progress to the development stages. However, we are now seeing biomarkers being validated with high diagnostic accuracy and improvements in standardization protocols, providing promise for the future of endometriosis blood biomarkers.

Inhibitory effect of telocyte-induced M1 macrophages on endometriosis: Targeting angiogenesis and invasion

PURPOSE

Telocytes (TCs), a novel type of stromal cells found in tissues, induce macrophage differentiation into classically activated macrophages (M1) types and enhance their phagocytic function. The purpose of this study was to investigate the inhibitory effects of TC-induced M1 macrophages on endometriosis (EMs).

METHODS

mouse uterine primary TCs and endometrial stromal cells (ESCs) were isolated and identified using double immunofluorescence staining. For the in vitro study, ESCs were treated with TC-induced M1 macrophages, and the vascular endothelial growth factor (VEGF), matrix metalloproteinase 9 (MMP9), and nuclear factor kappa B (NF-κb) genes were identified by quantitative real-time PCR (qRT-PCR) or western blotting (WB). For the in vivo study, an EMs mouse model received TC-conditioned medium (TCM) via abdominal administration, and characterized the inhibitory effects on growth (lesion weight, volume, and pathology), tissue-resident macrophages differentiation by immunostaining, angiogenic capacity (CD31 and VEGF), invasive capacity (MMP9), and NF-κb expression within EMs lesions.

RESULTS

immunofluorescent staining showed that uterine TCs expressed CD34+ and vimentin+, whereas ESCs expressed vimentin+ and cytokeratin-. At the cellular level, TC-induced M1 macrophages can significantly inhibit the expression of VEGF and MMP9 in ESCs through WB or qRT-PCR, possibly by suppressing the NF-κb pathway. The in vivo study showed that macrophages switch from the alternatively activated macrophages (M2) in untreated EMs lesions to the M1 subtype after TCM exposure. Thereby, TC-induced M1 macrophages contributed to the inhibition of EMs lesions. More importantly, this effect may be achieved by suppressing the expression of NF-κb to inhibit angiogenesis (CD31 and VEGF) and invasion (MMP9) in the tissue.

CONCLUSION

TC-induced M1 macrophages play a prevailing role in suppressing EMs by inhibiting angiogenic and invasive capacity through the NF-κb pathway, which provides a promising therapeutic approach for EMs.

Digestive system deep infiltrating endometriosis: What do we know

Digestive system infiltrating endometriosis (DSIE) is an uncommon form of endometriosis in the digestive system. DSIE often occurs in the intestines (especially the sigmoid rectum), liver, gallbladder and pancreas. Clinically, DSIE presents with the same symptoms as endometriosis, including cyclic pain, bleeding and infertility, in addition to specific biliary/intestinal obstruction and gastrointestinal bleeding. Compared to general endometriosis, DSIE has unique biological behaviour and pathophysiological mechanisms. Most DSIEs are deep invasive endometrioses, characterized by metastasis to the lymph nodes and lymphatic vessels, angiogenesis, peripheral nerve recruitment, fibrosis and invasion of surrounding tissues. DSIE-related peripheral angiogenesis is divided into three patterns: angiogenesis, vasculogenesis and inosculation. These patterns are regulated by interactions between multiple hypoxia-hormone cytokines. The nerve growth factors regulate the extensive neurofibril recruitment in DSIE lesions, which accounts for severe symptoms of deep pain. They are also associated with fibrosis and the aggressiveness of DSIE. Cyclic changes in DSIE lesions, recurrent inflammation and oxidative stress promote repeated tissue injury and repair (ReTIAR) mechanisms in the lesions, accelerating fibril formation and cancer-related mutations. Similar to malignant tumours, DSIE can also exhibit aggressiveness derived from collective cell migration mediated by E-cadherin and N-cadherin. This often makes DSIE misdiagnosed as a malignant tumour of the digestive system in clinical practice. In addition to surgery, novel treatments are urgently required to effectively eradicate this lesion.

Diagnostic significance of neutrophil to lymphocyte ratio in endometriosis: a systematic review and meta-analysis

BACKGROUND

The purpose of this systematic review and meta-analysis was to compile existing evidence on the significance of the NLR in predicting endometriosis in order to aid clinical decision-making and outcomes.

METHODS

We searched ProQuest, Web of Science, and PubMed for related studies published before January 2, 2023. Standardized mean difference (SMD) with a 95% confidence interval (CI) was reported for each outcome. Because a significant level of heterogeneity was found, we used the random-effects model to calculate pooled effects. We used Newcastle-Ottawa Scale (NOS) for quality assessment.

RESULTS

Overall, 18 article with were included in the analysis. A random-effect model revealed that patients with endometriosis had elevated levels of NLR compared to healthy controls (SMD = 0.79, 95% CI = 0.33 to 1.25, P < 0.001). Patients with endometriosis had elevated levels of NLR compared to those with other benign tumors (SMD = 0.85, 95% CI = 0.17 to 1.53, P = 0.014). In addition, NLR level of patients with stage III and IV endometriosis was not different from that of patients with stage I and II endometrioma (SMD = 0.30, 95% CI = -0.14 to 0.74, P = 0.18). However, NLR level was not different between endometriosis patients with and without peritoneal lesions (SMD = -0.12, 95% CI = -0.34to 0.10, P = 0.28), between patients with and without endometrioma (SMD = 0.20, 95% CI = -0.15 to 0.55, P = 0.26) and between endometriosis patients with and without deep lesions (SMD = 0.04, 95% CI = -0.20 to 0.28, P = 0.72). The pooled sensitivity of NLR was 0.67 (95% CI = 0.60-0.73), and the pooled specificity was 0.68 (95% CI, 0.62-0.73).

CONCLUSIONS

NLR might be utilized in clinics as a possible predictor to help clinicians diagnose endometriosis in affected women.

Blocking sphingosine 1-phosphate receptor 1 with modulators reduces immune cells infiltration and alleviates endometriosis in mice

RESEARCH QUESTION

Do sphingosine 1-phosphate (S1P) modulators have therapeutic effects on endometriosis in mice and, if they do, which receptor is responsible for these effects?

DESIGN

A surgically induced endometriosis mouse model was established. In the pilot experiment, lesions were harvested to assess fibrosis and inflammation and determine the optimal concentration of a broad-spectrum S1P modulator, FTY720. Subsequently, FTY720 was compared with a selective S1P receptor 1 modulator, SEW2871 to evaluate their effects on endometriotic lesion growth, fibrosis, inflammation and immune cell infiltration.

RESULTS

The results demonstrated that both FTY720 and SEW2871, two S1P receptor modulators, effectively inhibited the growth and fibrosis of endometriotic lesions. SEW2871 inhibited inflammation-related cytokine expression, including PTGS-2, IL-1β, TNF-α and TGF-β1, more effectively compared with FTY720. Lymphopaenia was mainly caused by FTY720, whereas SEW2871 had a lesser effect. Both FTY720 and SEW2871 significantly reduced CD45+ cells (P = 0.002 and P = 0.032, respectively) and F4/80+ cells (P < 0.001 and P = 0.004, respectively) infiltration into the lesions, with FTY720 exerting a strong regulatory effect on CD4+ T cells.

CONCLUSIONS

This study suggests that S1P receptor 1 could be investigated as a potential novel therapeutic target for endometriosis in the future.

Host immunity and KLF 11 deficiency together promote fibrosis in a mouse model of endometriosis

BACKGROUND

Endometriosis is a debilitating disease typically characterized by prolific fibrotic scarring. Earlier we reported downregulation of two transcription factors belonging TGF-βR signaling pathway Sp/Krüppel-like factor 11 (KLF11) and 10 (KLF10) in human endometriosis lesions. Here we investigated the role of these nuclear factors and immunity in the scaring fibrosis associated with endometriosis.

METHODS

We used a well characterized experimental mouse model of endometriosis. WT, KLF10 or KLF11 deficient mice were compared. The lesions were evaluated histologically, fibrosis was quantified with Masons' Trichome staining, immune-infiltrates were quantified by immunohistochemistry, peritoneal adhesions were score, gene expression was evaluated by bulk RNA sequencing.

RESULTS

Intense fibrotic reactions and large changes in gene expression were detected in KLF11 deficient implants associated with squamous metaplasia of the ectopic endometrium, as compared to KLF10 deficient or WT implants. Fibrosis was mitigated with pharmacologic agents that blocked histone acetylation or TGF-βR signaling or with genetic deficiency for SMAD3. The lesions were richly infiltrated with T-cells, regulatory T-cells, and innate immune cells. Fibrosis was exacerbated when implants expressed ectopic genes implicating autoimmunity as a major factor contributing to the scaring fibrosis.

CONCLUSIONS

Our findings identify KLF11 and TGF-βR signaling as cell intrinsic mechanisms and autoimmune responses as cell extrinsic mechanisms of scaring fibrosis in ectopic endometrium lesions.

GENERAL SIGNIFICANCE

Immunological factors associated with inflammation and tissue repair drive scaring fibrosis in experimental endometriosis, providing the rationale for immune therapy of endometriosis.

Influence of interleukin-8 polymorphism on endometriosis-related pelvic pain

Endometriosis presents a pro-inflammatory microenvironment influenced by cytokines, such as interleukin (IL)-8, which expression may be influenced by genetic polymorphisms. Therefore, we aimed to investigate the role of interleukin (IL)-8 rs4073 polymorphism in endometriosis' development and its related symptoms. A case-control study was conducted with 207 women with endometriosis and 193 healthy controls. Polymorphism was genotyped using a TaqMan validated assay. Associations were evaluated by binary logistic regression, using odds ratios (OR) and 95 % confidence intervals (CI), and P ≤ 0.05 was considered significant. Cases were younger (36 ± 6.8 versus 39 ± 8.4) and had lower body mass index (26.5 ± 5.3 versus 35.7 ± 6.3 Kg/m2) than controls (P < 0.001). Higher prevalence of symptoms and infertility was observed in cases, compared to controls (P < 0.001). Minor allele frequencies of IL-8 rs4073 (T) were 42.3 % and 39.9 % for cases and controls, respectively, and no associations were found between IL and 8 rs4073 polymorphism and endometriosis' prevalence or staging. However, the polymorphism was associated with chronic pelvic pain among cases (OR = 0.54; 95 %CI = 0.29-0.98). The IL-8 rs4073A > T polymorphism may contribute to lower IL-8 expression and, consequently, decrease endometriosis-related pelvic pain. These findings can support the early diagnosis of endometriosis' painful symptoms, preventing its complications, and allowing an individualized treatment.

The Presence of Pre-Existing Endometriotic Lesions Promotes the Growth of New Lesions in the Peritoneal Cavity

Endometriosis is a common gynecological disease which is characterized by endometriotic lesions outside the uterine cavity. In this study, we investigated whether the presence of pre-existing endometriotic lesions promotes the development of new lesions due to the exchange of cells and an altered peritoneal environment. For this purpose, uterine tissue samples from FVB/N wild-type donor mice were transplanted simultaneously or time-delayed with samples from transgenic FVB-Tg(CAG-luc-GFP)L2G85Chco/J donor mice into the abdominal cavity of FVB/N wild-type recipient mice. The formation of endometriotic lesions was analyzed by means of high-resolution ultrasound, bioluminescence imaging, histology and immunohistochemistry. Moreover, immune cells and inflammatory factors in the peritoneal fluid were assessed by flow cytometry and a cytokine array. These analyses revealed that the growth of newly developing endometriotic lesions is promoted by the presence of pre-existing ones. This is not due to an exchange of cells between both lesion types but rather caused by peritoneal inflammation induced by already established lesions. These findings indicate that, among other pathogenic mechanisms, the chronic nature of endometriosis may be driven by a lesion-induced inflammatory milieu in the peritoneal cavity, which creates favorable conditions for the development of new lesions.

Establishment of Immortalized Human Endometriotic Stromal Cell Line from Ectopic Lesion of a Patient with Endometriosis

Endometriosis is an estrogen-dependent inflammatory disease characterized by the growth of endometrial-like tissues containing endometrial stromal cells and glandular epithelium outside the uterine cavity. An insufficient response to progesterone contributes to disease progression and systemic inflammation during the pathogenesis of endometriosis. Patients with endometriosis usually experience painful symptoms, dysmenorrhea, and infertility, which contribute to a significant reduction in their quality of life. To determine the possible molecular mechanisms of endometriosis and explore novel therapeutic targets, we derived primary human ovarian endometriotic stromal cells (hOESCs) from a patient of reproductive age with ovarian endometriosis. In this study, we successfully established immortalized human ovarian endometriotic stromal cell lines (ihOESCs) using primary stromal cells obtained from endometriotic lesions to overcome short lifespan and growth inhibition. Immortalization of hOESCs with human telomerase reverse transcriptase (hTERT) transfection led to cells that maintained a proliferative state under passage culture conditions without mutagenesis during cellular senescence. The morphology and karyotype of ihOESCs were unchanged compared with those of hOESCs. Moreover, ihOESCs were continuously positive for vimentin and negative for E-cadherin expression. Following decidual stimuli and inflammatory responses, both hOESCs and ihOESCs sensitively express decidualization markers and proinflammatory cytokines. Collectively, we characterized ihOESCs to maintain their phenotypic and functional properties with a longer lifespan and normal physiological responses than those of hOESCs. These immortalized cells could aid in a detailed understanding of the pathological mechanisms of endometriosis.

Endometriosis in the era of precision medicine and impact on sexual and reproductive health across the lifespan and in diverse populations

Endometriosis is a common estrogen-dependent disorder wherein uterine lining tissue (endometrium) is found mainly in the pelvis where it causes inflammation, chronic pelvic pain, pain with intercourse and menses, and infertility. Recent evidence also supports a systemic inflammatory component that underlies associated co-morbidities, e.g., migraines and cardiovascular and autoimmune diseases. Genetics and environment contribute significantly to disease risk, and with the explosion of omics technologies, underlying mechanisms of symptoms are increasingly being elucidated, although novel and effective therapeutics for pain and infertility have lagged behind these advances. Moreover, there are stark disparities in diagnosis, access to care, and treatment among persons of color and transgender/nonbinary identity, socioeconomically disadvantaged populations, and adolescents, and a disturbing low awareness among health care providers, policymakers, and the lay public about endometriosis, which, if left undiagnosed and under-treated can lead to significant fibrosis, infertility, depression, and markedly diminished quality of life. This review summarizes endometriosis epidemiology, compelling evidence for its pathogenesis, mechanisms underlying its pathophysiology in the age of precision medicine, recent biomarker discovery, novel therapeutic approaches, and issues around reproductive justice for marginalized populations with this disorder spanning the past 100 years. As we enter the next revolution in health care and biomedical research, with rich molecular and clinical datasets, single-cell omics, and population-level data, endometriosis is well positioned to benefit from data-driven research leveraging computational and artificial intelligence approaches integrating data and predicting disease risk, diagnosis, response to medical and surgical therapies, and prognosis for recurrence.

Biomarkers of endometriosis

Endometriosis is one of the most severe female reproductive disorders, affecting 6-10% of women between 18 and 35. It is a gynaecological condition where endometrial tissue develops and settles outside the uterus. The aetiology of endometriosis is primarily influenced by genetic, epigenetic, and non-genetic variables, making it highly challenging to create a therapeutic therapy explicitly targeting the ectopic tissue. The delay in the treatment is due to the limitations in the diagnostic approaches, which are restricted to invasive techniques such as laparoscopy or laparotomy. This accords to 70% of the women being diagnosed at later stages. By understanding the subject, several treatment medications have been produced to lessen the disease's symptoms. Nevertheless, endometriosis cannot be permanently cured. A viable or persuasive standard screening test for endometriosis must be utilized in a clinical context. A helpful assessment method for the early identification of endometriosis could be biomarkers. A major research priority is the identification of a biomarker that is sensitive and specific enough for detecting endometriosis. The present article has reviewed studies published on the expression of biomarkers of endometriosis. It outlines various biomarkers from different sample types, such as serum/plasma and urine, in addition to tissue. This would provide a non-invasive approach to diagnosing the disease at the initial stages without any harmful repercussions. Future high-throughput advances in science and technology are anticipated to result in the creation of a potent remedy for endometriosis. To achieve successful outcomes, it is necessary to research the discussed biomarkers that demonstrate substantial results extensively.

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.

Synergy between Th1 and Th2 responses during endometriosis: A review of current understanding

Endometriosis is widely perceived as an estrogen-dependent chronic disorder with infertility and pelvic pain. Although the etiology of endometriosis has remained elusive, many studies have proclaimed the relevance of immune system disorders with endometriosis. With the discovery that the dysregulation of multiple biological functions in endometriosis is caused by the aberrant differentiation of T helper cells, a shift towards Th2 immune response may account for the disease progression. This review attempts to present mechanisms of cytokines, chemokines, signal pathways, transcription factors and some other factors related with the derivation of Th1/Th2 immune response involved in the development of endometriosis. The current understanding of treatment approaches and potential therapeutic targets will also be outlined with brief discussion.

Donor Mesenchymal Stem Cells Program Bone Marrow, Altering Macrophages, and Suppressing Endometriosis in Mice

Endometriosis is a chronic inflammatory gynecological disorder regulated by estrogen and characterized by the growth of endometrial tissue outside the uterus. We have previously demonstrated that mesenchymal stem cells (MSCs) contribute directly to endometriosis. Here, we investigated an indirect effect; we hypothesized that MSCs may also impact the bone marrow (BM) by regulating bone marrow-derived inflammatory cells. Endometriosis was induced in mice by transplanting uterine tissue into recipient mice followed by BM transplant. Control or MSC conditioned BM was injected retro-orbitally. Direct administration of MSCs outside of the setting of BM conditioning did not alter endometriosis. Coculture of an undifferentiated macrophage cell line with MSCs in vitro led to a reduction of M1 and increased M2 macrophages as determined by fluorescence-activated cell sorting and western blot. Conditioning of BM with MSCs and transplantation into a mouse model inhibited endometriotic lesion development and reduced lesion volume by sevenfold compared to BM transplant without MSCs conditioning. Immunohistochemistry and immunofluorescence showed that MSC conditioned BM reduced the infiltration of macrophages and neutrophils into endometriotic lesions by twofold and decreased the proportion of M1 compared to M2 macrophages, reducing inflammation and likely promoting tissue repair. Expression of several inflammatory markers measured by quantitative real-time polymerase chain reaction, including tumor necrosis factor alpha and CXCR4, was decreased in the conditioned BM. Donor MSCs were not detected in recipient BM or endometriotic lesions, suggesting that MSCs actively program the transplanted BM. Taken together, these data show that individual characteristics of BM have an unexpected role in the development of endometriosis. BM remodeling and alterations in the inflammatory response are also potential treatments for endometriosis. Identification of the molecular basis for BM programing by MSCs will lead to a better understanding of the immune system contribution to this disease and may lead to new therapeutic targets for endometriosis.

Evaluation of Immune Infiltrates in Ovarian Endometriosis and Endometriosis-Associated Ovarian Cancer: Relationship with Histological and Clinical Features

BACKGROUND

the association between ovarian endometriosis (OE) and endometriosis-associated ovarian cancer (EAOC) is extensively documented, and misfunction of the immune system might be involved. The primary objective of this study was to identify and compare the spatial distribution of tumour-infiltrating lymphocytes (TILs) and tumour-associated macrophages (TAMs) in OE and EAOC. Secondary objectives included the analysis of the relationship between immunosuppressive populations and T-cell exhaustion markers in both groups.

METHODS

TILs (CD3, CD4, and CD8) and macrophages (CD163) were assessed by immunochemistry. Exhaustion markers (PD-1, TIM3, CD39, and FOXP3) and their relationship with tumour-associated macrophages (CD163) were assessed by immunofluorescence on paraffin-embedded samples from n = 43 OE and n = 54 EAOC patients.

RESULTS

we observed a predominantly intraepithelial CD3+ distribution in OE but both an intraepithelial and stromal pattern in EAOC (p < 0.001). TILs were more abundant in OE (p < 0.001), but higher TILs significantly correlated with a longer overall survival and disease-free survival in EAOC (p < 0.05). CD39 and FOXP3 significantly correlated with each other and CD163 (p < 0.05) at the epithelial level in moderate/intense CD4 EAOC, whereas in moderate/intense CD8+, PD-1+ and TIM3+ significantly correlated (p = 0.009). Finally, T-cell exhaustion markers FOXP3-CD39 were decreased and PD-1-TIM3 were significantly increased in EAOC (p < 0.05).

CONCLUSIONS

the dysregulation of TILs, TAMs, and T-cell exhaustion might play a role in the malignization of OE to EAOC.

The role of CD8+ T cells in endometriosis: a systematic review

Background

Endometriosis is a chronic disease affecting 6-10% of women of reproductive age. It is an important cause of infertility and chronic pelvic pain with poorly understood aetiology. CD8+ T (CD8 T) cells were shown to be linked to infertility and chronic pain and play a significant role in lesion clearance in other pathologies, yet their function in endometriosis is unknown. We systematically evaluated the literature on the CD8 T in peripheral blood and endometriosis-associated tissues to determine the current understanding of their pathophysiological and clinical relevance in the disease and associated conditions (e.g. infertility and pelvic pain).

Methods

Four databases were searched (MEDLINE, EMBASE, Web of Science, CINAHL), from database inception until September 2022, for papers written in the English language with database-specific relevant terms/free-text terms from two categories: CD8 T cells and endometriosis. We included peer-reviewed papers investigating CD8 T cells in peripheral blood and endometriosis-associated tissues of patients with surgically confirmed endometriosis between menarche and menopause, and animal models with oestrous cycles. Studies enrolling participants with other gynaecological pathologies (except uterine fibroids and tubal factor infertility used as controls), cancer, immune diseases, or taking immune or hormonal therapy were excluded.

Results

28 published case-control studies and gene set analyses investigating CD8 T cells in endometriosis were included. Data consistently indicate that CD8 T cells are enriched in endometriotic lesions in comparison to eutopic endometrium, with no differences in peripheral blood CD8 T populations between patients and healthy controls. Evidence on CD8 T cells in peritoneal fluid and eutopic endometrium is conflicting. CD8 T cell cytotoxicity was increased in the menstrual effluent of patients, and genomic analyses have shown a clear trend of enriched CD8 T effector memory cells in the eutopic endometrium of patients.

Conclusion

Literature on CD8 T cells in endometriosis-associated tissues is inconsistent. Increased CD8 T levels are found in endometriotic lesions, however, their activation potential is understudied in all relevant tissues. Future research should focus on identifying clinically relevant phenotypes to support the development of non-invasive diagnostic and treatment strategies.

Systematic Review Registration

PROSPERO identifier CRD42021233304.

The Sphingosine 1-Phosphate Axis: an Emerging Therapeutic Opportunity for Endometriosis

Endometriosis is a common condition in women of reproductive age, but its current interventions are unsatisfactory. Recent research discovered a dysregulation of the sphingosine 1-phosphate (S1P) signaling pathway in endometriosis and showed a positive outcome by targeting it. The S1P axis participates in a series of fundamental pathophysiological processes. This narrative review is trying to expound the reported and putative (due to limited reports in this area for now) interactions between the S1P axis and endometriosis in those pathophysiological processes, to provide some perspectives for future research. In short, S1P signaling pathway is highly activated in the endometriotic lesion. The S1P concentration has a surge in the endometriotic cyst fluid and the peritoneal fluid, with the downstream dysregulation of its receptors. The S1P axis plays an essential role in the migration and activation of the immune cells, fibrosis, angiogenesis, pain-related hyperalgesia, and innervation. S1P receptor (S1PR) modulators showed an impressive therapeutic effect by targeting the different S1P receptors in the endometriosis model, and many other conditions resemble endometriosis. And several of them already got approval for clinical application in many diseases, which means a drug repurposing direction and a rapid clinical translation for endometriosis treatments.

A Lifelong Impact on Endometriosis: Pathophysiology and Pharmacological Treatment

Endometriosis is a chronic inflammatory disease associated with bothersome symptoms in premenopausal women and is complicated with long-term systemic impacts in the post-menopausal stage. It is generally defined by the presence of endometrial-like tissue outside the uterine cavity, which causes menstrual disorders, chronic pelvic pain, and infertility. Endometriotic lesions can also spread and grow in extra-pelvic sites; the chronic inflammatory status can cause systemic effects, including metabolic disorder, immune dysregulation, and cardiovascular diseases. The uncertain etiologies of endometriosis and their diverse presentations limit the treatment efficacy. High recurrence risk and intolerable side effects result in poor compliance. Current studies for endometriosis have paid attention to the advances in hormonal, neurological, and immunological approaches to the pathophysiology and their potential pharmacological intervention. Here we provide an overview of the lifelong impacts of endometriosis and summarize the updated consensus on therapeutic strategies.

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

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

Expression of Gal-9 on Dendritic Cells and Soluble Forms of TIM-3/Gal-9 in Patients Suffering from Endometriosis

Immune system dysregulation is clinically evident in the pathogenesis of endometriosis (EMS). Changes in the dendritic cells (DCs) activity or phenotype may be involved in the implantation and growth of endometrial tissue outside the uterus in the disease. The TIM-3/Gal-9 axis is implicated in the development of immune tolerance. However, the knowledge about the exact role of this pathway in the EMS is extremely poor. In the present study, we evaluated the expression of Gal-9 on myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) in the peripheral blood (PB) and peritoneal fluid (PF) of both EMS patients (n = 82) and healthy subjects (n = 10) via flow cytometry. We also investigated the concentrations of soluble Gal-9 and TIM-3 in the plasma and PF of EMS patients and the control group using ELISA. We showed significantly elevated percentages of mDCs-Gal-9⁺ and pDCs-Gal-9⁺, and significantly higher concentrations of the soluble form of Gal-9 and TIM-3 in the PF of EMS patients than in circulation. Our results led us to conclude that the accumulation of Gal-9 expressing mDCs and pDCs in the PF and high sTIM-3/Gal-9 production in the peritoneal cavity could represent the hallmark of immune regulation in EMS patients, which may augment the inflammatory process and development/maintenance of local immunosuppression.

Clotrimazole is effective, safe and tolerable for the treatment of endometriosis and functions by downregulating inducible nitric oxide synthase and modulating oxidative stress biomarkers

This study investigated the mechanism of action of clotrimazole (CTZ) and its adverse effects in a model of endometriosis. After autologous endometrial implantation, 18 rats were randomized into two treatment groups: 200 mg/kg CTZ or vehicle for 15 consecutive days. The lesion growth, implant size, glandular atrophy, nitric oxide (NO) serum levels, number of macrophage cells and inducible nitric oxide synthase (iNOS) immunoreactivity were significantly reduced in the CTZ group compared with the control. CTZ (p < 0.05) reduced the lipid peroxidation and protein carbonylation levels in the liver but did not alter the superoxide dismutase (SOD), glutathione (GSH) or glutathione S-transferase (GST) levels in the brain; however, the drug significantly reduced SOD activity and enhanced GST activity in the liver. These results suggest that CTZ interferes with reactive nitrogen species production by downregulating iNOS expression and thus enhances the antioxidant system to promote atrophy and regression of endometriotic lesions, without adverse effects on the brain and/or liver.

The effects of Rituximab on experimental endometriosis model in rats

AIM

Endometriosis is a common, chronic benign gynecologic disease and distresses women in their reproductive age. Yet the pathogenesis of endometriosis is not clear, multifactorial mechanisms have been characterized for the initiation, progression, and regression of this disease. It has been suggested that immune cells in the lymphoid lineage play essential roles in accepting or rejecting the survival, implantation, and proliferation of endometrial and endometriotic cells and, dysfunction of B-lymphocytes (B-cells) are one of the major causes for the progression of endometriosis. In this study, we aimed to evaluate the potential therapeutic efficacy of Rituximab, an inhibitor for B-cells, for endometriosis in an experimental animal model.

METHODS

Experimental endometriosis animal model has been utilized using mature female rats. Rats underwent surgery to initiate endometriosis on the abdominal wall. After confirming for endometriosis, rats were treated with either Rituximab or saline solution. After 14 days of treatment, implants were dissected, and evaluated for volumes and histological features. Anti-CD-20 antibody was used for immunohistochemistry scoring purposes.

RESULTS

There is significant decrease in the volume of endometriotic implants after treatment with Rituximab (188.81 ± 149.42 vs 20.37 ± 13.08, p = 0.001). There are also significant differences for the B-cell count and fibrosis score between the control and treatment groups (3.08 ± 2.6 vs 1.56 ± 1.42., p = 0.043).

CONCLUSION

In an experimental rat endometriosis model, we assessed Rituximab, an antibody for B-lymphocyte, as a candidate medical treatment for endometriosis. Additional studies are required to further evaluate the effects of Rituximab on the prevention of endometriosis.

A long-acting anti-IL-8 antibody improves inflammation and fibrosis in endometriosis

Current pharmacological treatments for endometriosis are limited to hormonal agents that can relieve pain but cannot cure the disease. Therefore, the development of a disease-modifying drug for endometriosis is an unmet medical need. By studying human endometriotic samples, we found that the progression of endometriosis was associated with the development of inflammation and fibrosis. In addition, IL-8 expression was highly up-regulated in endometriotic tissues and closely correlated with disease progression. We created a long-acting recycling antibody against IL-8 (AMY109) and evaluated its clinical potency. Because rodents do not produce IL-8 and do not experience menstruation, we analyzed the lesions in cynomolgus monkeys that spontaneously developed endometriosis and in a surgically induced endometriosis monkey model. Both spontaneously developed and surgically induced endometriotic lesions demonstrated pathophysiology that was highly similar to that of human endometriosis. Once-a-month subcutaneous injection of AMY109 to monkeys with surgically induced endometriosis reduced the volume of nodular lesions, lowered the Revised American Society for Reproductive Medicine score as modified for monkeys, and ameliorated fibrosis and adhesions. In addition, experiments using cells derived from human endometriosis revealed that AMY109 inhibited the recruitment of neutrophils to endometriotic lesions and the production of monocyte chemoattractant protein-1 from neutrophils. Thus, AMY109 may represent a disease-modifying therapy for patients with endometriosis.

Endometriosis is associated with pregnancy loss: a nationwide historical cohort study

OBJECTIVE

To study whether endometriosis is associated with pregnancy loss and recurrent pregnancy loss (RPL).

DESIGN

Nationwide historical cohort study with a nested case-control analysis.

SETTING

National health registers.

PATIENT(S)

A total of 29,563 women born between 1957 and 1997 were identified in the national health registers, diagnosed with endometriosis between 1977 and 2017, and age-matched 1:10 with 295,630 women without endometriosis. The number of pregnancy losses was assessed, and data were analyzed with conditional logistic regression.

INTERVENTION(S)

Endometriosis (International Classification of Diseases, 8th Revision, 62530-62539, and International Classification of Diseases, 10th Revision, DN80.0-9).

MAIN OUTCOME MEASURE(S)

The primary outcomes of interest were the numbers of pregnancy losses categorized as 0, 1, 2, and ≥ 3 losses, unadjusted and adjusted for gravidity, and RPL. The secondary outcome measures were the predefined types of pregnancy losses. Pregnancy loss was defined as the spontaneous demise of a pregnancy until 22 weeks of gestation. Primary RPL was defined as 3 or more consecutive pregnancy losses with no prior live birth or stillbirth, and secondary RPL was defined as 1 or more births followed by 3 or more consecutive losses.

RESULT(S)

A total of 18.9%, 3.9%, and 2.1% of ever-pregnant women with endometriosis had 1, 2, and ≥ 3 pregnancy losses compared with 17.3%, 3.5%, and 1.5% of the women without endometriosis, corresponding to the odds ratios of 1.13 (95% confidence interval, 1.09-1.17), 1.18 (1.10-1.26), and 1.44 (1.31-1.59), respectively. When adjusted also for gravidity, the corresponding results were 1.37 (95% confidence interval, 1.32-1.42), 1.75 (1.62-1.89), and 2.57 (2.31-2.85), respectively. The following predefined subgroups of RPL were positively associated with endometriosis: primary; secondary; secondary after giving birth to a boy; after a complicated delivery; and ≥ 3 pregnancy losses before the age of 30 years. Six endometriosis subgroup analyses found an association between endometriosis and pregnancy loss. These analyses were women diagnosed in the 4 decades between 1977 and 2017, women with adenomyosis, and women with adenomyosis only.

CONCLUSION(S)

This nationwide cohort study found endometriosis to be associated with pregnancy loss and RPL, and the association strengthened with an increasing number of losses.

Myeloid-derived suppressor cells: A new emerging player in endometriosis

Endometriosis is a common gynecological disorder defined by the presence of endometrial tissue outside the uterus. This is commonly associated with chronic pelvic pain, infertility, and dysmenorrhea, which occurs in approximately 10% of women of reproductive age. Although the exact mechanism remains uncertain, it has been widely accepted to be an estrogen-dependent and inflammatory disease. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of immune cells with immunosuppressive capacity and non-immunological functions. They have been found to be aggressively involved in the pathologies of various disorders. In regards to tumors, the functions of MDSCs have been profoundly shown to inhibit tumor immune response and to promote angiogenesis, tumor metastasis, fibrosis, and epithelial-mesenchymal transition (EMT). In recent years, the elevation of MDSCs in endometriosis was reported by several studies that provoke the assumption that MDSCs might exert similar roles to promote the development of endometriosis. Such that, precision treatments targeting MDSCs might be a promising direction for future study. Herein, we will review the research progress of MDSCs in endometriosis and its potential relevance to the pathogenesis, progression, and therapeutics strategy of endometriosis.

Potential link between the nerve injury-induced protein (Ninjurin) and the pathogenesis of endometriosis

Endometriosis remains a widespread but severe gynecological disease in women of reproductive age, with an unknown etiology and few treatment choices. The menstrual reflux theory is largely accepted as the underlying etiology but does not explain the morbidity or unpleasant pain sensations of endometriosis. The neurological and immune systems are both involved in pain mechanisms of endometriosis, and interlinked through a complex combination of cytokines and neurotransmitters. Numerous pieces of evidence suggest that the nerve injury-inducible protein, Ninjurin, is actively expressed in endometriosis lesions, which contributes to the etiology and development of endometriosis. It may be explored in the future as a novel therapeutic target. The aim of the present review was to elucidate the multifaceted role of Ninjurin. Furthermore, we summarize the association of Ninjurin with the pain mechanism of endometriosis and outline the future research directions. A novel therapeutic pathway can be discovered based on the potential pathogenic variables.

Review of the Potential Therapeutic Effects and Molecular Mechanisms of Resveratrol on Endometriosis

Endometriosis is a hormone-dependent inflammatory disease characterized by the existence of endometrial tissues outside the uterine cavity. Pharmacotherapy and surgery are the current dominant management options for endometriosis. The greater incidence of recurrence and reoperation after surgical treatment as well as the adverse effects of medical approaches predispose patients to potential limitations for their long-term usage. Consequently, it is essential to explore novel supplementary and alternative drugs to ameliorate the therapeutic outcomes of endometriotic patients. Resveratrol is a phenolic compound that has attracted increasing interest from many researchers due to its pleiotropic biological activities. Here, we review the possible therapeutic efficacies and molecular mechanisms of resveratrol against endometriosis based on in vitro, animal, and clinical studies. The potential mechanisms of resveratrol include anti-proliferative, pro-apoptotic, anti-angiogenic, anti-oxidative stress, anti-invasive and anti-adhesive effects, thereby suggesting that resveratrol is a promising candidate for endometriosis. Because most studies have investigated the effectiveness of resveratrol on endometriosis via in vitro trials and/or experimental animal models, further high-quality clinical trials should be undertaken to comprehensively estimate the clinical application feasibility of resveratrol on endometriosis.

The bidirectional relationship between endometriosis and microbiome

Endometriosis has been described by many different theories of pathogenesis over the years. It is now also appreciated to be a state of chronic inflammation, and the role of immune dysfunction in its development has been proven. There is increasing evidence to support the role of the microbiome in the formation and progression of endometriosis via inflammatory pathways. The dysbiosis seen in endometriosis is thought to be both causative and a consequence of the pathogenesis. Gut, peritoneal fluid and female reproductive tract microbiota has been studied to understand if there are any microbiome signatures specific to endometriosis. New research on how to manipulate the microbiome for better detection and treatment of endometriosis is emerging.

Natural Killer Cell Receptors and Endometriosis: A Systematic Review

Endometriosis is a chronic inflammatory disorder, characterized by the presence of endometrial cells outside the uterine cavity. An increasing number of studies correlate the immune system with endometriosis, particularly NK receptors (NKR), which have been suggested to play an essential role in the pathogenesis of the disease. This systematic review aims to enlighten the role of NKR in endometriosis. A literature search was performed independently by two reviewers, to identify studies assessing the role of NKR in endometriosis. In total, 18 studies were included. Endometriosis pathogenesis seems to be marked by the overexpression of NK inhibitor receptors (KIRS), namely, CD158a+, KIR2DL1, CD94/NKG2A, PD-1, NKB1, and EB6, and inhibiting ligands such as PD-L1, HLA-E, HLA-G, and HLA-I. Concurrently, there is a decrease in NK-activating receptors and natural cytotoxicity receptors (NCRs), such as NKp46, NKp30, and NKG2D. The immune shift from NK surveillance to NK suppression is also apparent in the greater relative number of ITIM domains compared with ITAM domains in NKRs. In conclusion, NK receptor activity seems to dictate the immunocompetency of women to clear endometriotic cells from the peritoneal cavity. Future research could explore NKRs as therapeutic targets, such as that which is now well established in cancer therapy through immunotherapy.

Endometriosis and COVID-19: A Systematic Review and Meta-Analysis

Endometriosis is defined as ectopic endometrial tissues dispersed outside the endometrium. This can cause disruption in hormonal and immunological processes, which may increase susceptibility to SARS-CoV-2 infection. Worsening of endometriosis symptoms may occur as a result of this infection. The aim of our review was to estimate the pooled prevalence of SARS-CoV-2 infection and the health impacts of the COVID-19 pandemic in endometriosis patients. We conducted a systematic review and meta-analysis. MEDLINE, Science Direct, Scopus, and Google Scholar databases were searched, using the keywords: (endometriosis) AND (COVID-19 OR SARS-CoV-2). Forest plots and pooled estimates were created using the Open Meta Analyst software. After screening 474 articles, 19 studies met the eligibility criteria for the systematic review, and 15 studies were included in the meta-analyses. A total of 17,799 patients were analyzed. The pooled prevalence of SARS-CoV-2 infection in endometriosis patients was 7.5%. Pooled estimates for the health impacts were 47.2% for decreased access to medical care, 49.3% increase in dysmenorrhea, 75% increase in anxiety, 59.4% increase in depression, and 68.9% increase in fatigue. Endometriosis patients were undeniably impacted by the COVID-19 pandemic, which caused the worsening of symptoms such as dysmenorrhea, pelvic pain, anxiety, depression, and fatigue.

Anhedonia in endometriosis: An unexplored symptom

Anhedonia is the diminished motivation and sensitivity to pleasurable stimuli. It has been reported to be more prevalent in patients with chronic pain as compared to healthy controls. Endometriosis is a chronic inflammatory systemic disease with a significant psychosocial impact that compromises wellbeing and the day-to-day life of patients. Women with endometriosis show significant psychological distress, even more pervasive when chronic pelvic pain is present. In the current review we will discuss the role of anhedonia in endometriotic chronic pelvic pain. We will also present new lines of research that could lead to more fully clarifying the psychological impact of endometriosis and its detrimental repercussions to quality of life and mental health.

Potential impact of COVID-19 pandemic on endometriosis

The impact of coronavirus disease 2019 (COVID-19) on endometriosis (EM) is currently unclear. Here, we aimed to describe the potential influence of COVID-19 on the pathogenesis, clinical symptoms, and treatment of EM. The cytokine storm caused by COVID-19 may induce the occurrence and progression of EM, and immunosuppression of COVID-19 may help the ectopic endometrium escape from immune clearance. Consequently, the forced social isolation and the cancelation of non-emergency medical treatment during the COVID-19 pandemic aggravate anxiety and psychological pressure, which can aggravate the symptoms related to EM and delay routine medical services.

Epigenetic regulation and T-cell responses in endometriosis – something other than autoimmunity

Endometriosis is defined as the presence of endometrial-like glands and stroma located outside the uterine cavity. This common, estrogen dependent, inflammatory condition affects up to 15% of reproductive-aged women and is a well-recognized cause of chronic pelvic pain and infertility. Despite the still unknown etiology of endometriosis, much evidence suggests the participation of epigenetic mechanisms in the disease etiopathogenesis. The main rationale is based on the fact that heritable phenotype changes that do not involve alterations in the DNA sequence are common triggers for hormonal, immunological, and inflammatory disorders, which play a key role in the formation of endometriotic foci. Epigenetic mechanisms regulating T-cell responses, including DNA methylation and posttranslational histone modifications, deserve attention because tissue-resident T lymphocytes work in concert with organ structural cells to generate appropriate immune responses and are functionally shaped by organ-specific environmental conditions. Thus, a failure to precisely regulate immune cell transcription may result in compromised immunological integrity of the organ with an increased risk of inflammatory disorders. The coexistence of endometriosis and autoimmunity is a well-known occurrence. Recent research results indicate regulatory T-cell (Treg) alterations in endometriosis, and an increased number of highly active Tregs and macrophages have been found in peritoneal fluid from women with endometriosis. Elimination of the regulatory function of T cells and an imbalance between T helper cells of the Th1 and Th2 types have been reported in the endometria of women with endometriosis-associated infertility. This review aims to present the state of the art in recognition epigenetic reprogramming of T cells as the key factor in the pathophysiology of endometriosis in the context of T-cell-related autoimmunity. The new potential therapeutic approaches based on epigenetic modulation and/or adoptive transfer of T cells will also be outlined.

The role of the Immune System in the Development of Endometriosis

Endometriosis is a chronic disease that affects about 10% of women of reproductive age. It can contribute to pelvic pain, infertility or other conditions such as asthma, cardiovascular disease, breast or ovarian cancer. Research has shown that one of the conditions for the development of endometrial lesions is the dysfunction of the immune system. It appears that immune cells, such as neutrophils, macrophages, NK cells and dendritic cells, may play a specific role in the angiogenesis, growth and invasion of endometriosis cells. Immune cells secrete cytokines and defensins that also affect the endometriosis environment. This review discusses the various components of the immune system that are involved in the formation of endometrial lesions in women.

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.

Activation of α7 nicotinic acetylcholine receptor retards the development of endometriosis

BACKGROUND

Women with endometriosis have been shown to have a reduced vagal tone as compared with controls and vagotomy promoted while vagus nerve stimulation (VNS) decelerated the progression of endometriosis in mice. Extensive research also has shown that the activation of the cholinergic anti-inflammatory pathway by VNS activates α7 nicotinic acetylcholine receptor (α7nAChR), potently reducing inflammation. Yet whether α7nAChR plays any role in endometriosis is unknown. We evaluated its expression in normal endometrium, ovarian and deep endometriotic lesions, and evaluated its role in the development of endometriosis.

METHODS

Immunohistochemistry analyses of α7nAChR in endometriotic lesions as well as control endometrium, and quantification of tissue fibrosis by Masson trichrome staining were performed. Mouse experiments were conducted to evaluate the impact of α7nAChR activation or suppression on lesional progression and possible therapeutic effect. Finally, in vitro experiments were conducted to evaluate the effect of activation of α7nAChR on epithelial-mesenchymal transition (EMT), fibroblast-to-myofibroblast transdifferentiation (FMT), smooth muscle metaplasia (SMM) and fibrogenesis in an endometriotic epithelial cell line and primary endometriotic stromal cells derived from ovarian endometrioma tissue samples.

RESULTS

Immunostaining of α7nAChR was significantly reduced in human endometriotic epithelial cells as compared with their counterpart in normal endometrium. Lesional α7nAChR staining levels correlated negatively with lesional fibrosis and the severity of dysmenorrhea. The α7nAChR agonist significantly impeded the development of endometriotic lesions in mouse models possibly through hindrance of EMT and FMT. It also demonstrated therapeutic effects in mice with induced deep endometriosis. Treatment of endometriotic epithelial and stromal cells with an α7nAChR agonist significantly abrogated platelet-induced EMT, FMT and SMM, and suppressed cellular contractility and collagen production.

CONCLUSIONS

α7nAChR is suppressed in endometriotic lesions, and its activation by pharmacological means can impede EMT, FMT, SMM, and fibrogenesis of endometriotic lesions. As such, α7nAChR can be rightfully viewed as a potential target for therapeutic invention.

TRIAL REGISTRATION

Not applicable.