Endometriosis-Associated Macrophages: Origin, Phenotype, and Function

Ferroptosis in Endometriosis: Traditional Chinese Medicine Interventions and Mechanistic Insights

Endometriosis (EMS) is a chronic, estrogen-dependent inflammatory disease affecting 5-10% of women of reproductive age, characterized by the growth of endometrial tissue on the outside of the uterus. The dysregulation of iron metabolism leads to the accumulation of iron ions at the lesion sites, resulting in oxidative stress and pro-inflammatory responses that promote the progression of EMS. The mechanisms underlying ferroptosis in EMS primarily involve iron accumulation, lipid peroxidation, and loss of glutathione peroxidase 4 activity. These mechanisms confer resistance to ferroptosis within the ectopic tissues and facilitate cell survival and proliferation. Traditional Chinese medicine (TCM) has demonstrated therapeutic potential for modulating ferroptosis. Studies have shown that TCM monomers may regulate ferroptosis by modulating iron transport proteins and anti-oxidant defense mechanisms. TCM formulas employ distinct treatment strategies depending on the stage of EMS: in the early stages, they promote ferroptosis to control lesion growth, whereas in the later stages, they inhibit ferroptosis to reduce oxidative stress and inflammation in order to improve reproductive health and slow disease progression. This study provides a new perspective on potential therapeutic strategies for the management of EMS by summarizing the role of ferroptosis in its pathological mechanisms and reviewing findings on the use of TCM in regulating ferroptosis.

Unraveling shared diagnostic genes and cellular microenvironmental changes in endometriosis and recurrent implantation failure through multi-omics analysis

Endometriosis and Recurrent Implantation Failure (RIF) are both pivotal clinical issues within the realm of reproductive medicine, sharing significant overlap in their pathophysiological mechanisms. However, research exploring the commonalities between these two conditions remains relatively scarce, and reliable shared diagnostic biomarkers have yet to be identified. In this study, we integrated transcriptomic and single-cell sequencing data from the Gene Expression Omnibus (GEO) database to identify shared diagnostic genes and alterations in the cellular microenvironment between EMs and RIF. Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were employed to identify key genes. Machine learning algorithms, including Random Forest (RF) and XGBoost, were utilized to screen for shared diagnostic genes, which were subsequently validated through receiver operating characteristic (ROC) analysis and clinical prediction models. Single-cell analysis was conducted to investigate the expression patterns of these diagnostic genes across various cellular subpopulations. Additionally, gene set enrichment analysis (GSEA) and competing endogenous RNA (ceRNA) network analysis were employed to further elucidate the biological functions and regulatory mechanisms of these genes. A total of 16 key genes were identified, which were predominantly expressed in fibroblasts. Through machine learning, the optimal model combining RF and XGBoost was selected to identify the shared diagnostic genes PDIA4 and PGBD5. Single-cell analysis revealed significant differences in the expression of these diagnostic genes in fibroblasts between normal and disease states. ROC analysis showed that the Area Under the Curve (AUC) values for individual genes in disease diagnosis were all above 0.7. The constructed clinical prediction model demonstrated robust predictive capacity for the disease. Immune infiltration analysis indicated that M2 macrophages and γδ T cells play important roles in the pathogenesis of EMs and RIF. GSEA revealed that these genes are involved in immune responses, vascular function, and hormone regulation, and are regulated by miR-3121-3p. This study provides comprehensive insights into the shared cellular microenvironmental alterations and molecular mechanisms underlying EMs and RIF. The identification of PDIA4 and PGBD5 as shared diagnostic biomarkers offers new avenues for early diagnosis and targeted treatment of EMs-related RIF. Future work will focus on validating these findings in larger cohorts and exploring their therapeutic potential.

Metformin reverses infertility in a mouse model of endometriosis: unveiling disease pathways and implications for future clinical approaches

RESEARCH QUESTION

Does metformin reverse endometriosis-associated infertility?

DESIGN

Endometriosis was induced by transplanting uterus fragments from B6CBAF1 mice into recipients of the same strain. The mice were divided into groups: endometriosis (End, n = 24), sham-operated (Sham, n = 12), endometriosis with metformin (0.5mg/ml) orally administered for 3 months (EndMet, n = 21) and sham-operated metformin-treated (ShamMet, n = 16). Implant growth was monitored using ultrasonography. Fibrosis was computer-assisted quantified in Masson's trichrome-stained sections of eutopic (EuEnd) and ectopic (EcEnd) endometrium. PCNA, CYP17a1, F4/80 and galectin-3 were analysed by immunofluorescence and western blotting, and NFkB, GPX-1 and HO-1 only by western blotting. Statistical significance was set at P <0.05.

RESULTS

The endometriosis model was successfully established. The End groups showed lower fertility rates than sham-operated mice (P = 0.0034), whereas metformin treatment increased the number of fetuses per pregnant mouse (P = 0.0295), restoring fertility to control levels; it also slowed implant growth and vascularization. Metformin also restored PCNA expression and fibrosis levels to those of non-treated EuSham mice. PCNA expression decreased in pregnant mice (P <0.0178). Metformin diminished CYP17a1 expression in EcEnd versus EuEnd non-treated tissues and conversely up-regulated F4/80 in EuEnd tissue (P <0.0170), and galectin-3, NFkB and the antioxidant enzymes HO-1 and GPX-1 in EcEnd tissue (P <0.0293), in non-mated mice.

CONCLUSIONS

These results indicate that application of metformin can alleviate oxidative stress and mitigate fibrosis in endometriosis lesions in a murine model of endometriosis, which highlights metformin's potential as a pharmacological intervention for improving infertility in endometriosis.

Prospects for potential therapy targeting immune‑associated factors in endometriosis (Review)

Endometriosis (EM) is a chronic inflammatory disease that is one of the most common causes of gynecological systemic lesions in women before menopause. The most representative histological feature of EM is that the endometrium appears outside of the uterine cavity, often in the ovary. Although it is generally accepted that the epithelial and stromal cells of the ectopic endometrium are not malignant, they still have numerous similarities to malignant tumors, including considerable changes to the immune microenvironment (immune monitoring disorder), the creation of a specific hormone environment, high levels of oxidative stress, chronic inflammation and abnormal immune cell regulation. The pathogenesis of EM is not fully understood, which makes it difficult to identify specific biomarkers and potential therapeutic targets for early disease diagnosis and effective treatment. However, considerable progress has been made in this field over the past few decades. The purpose of the present review is to summarize the confirmed and potential biomarkers for EM, and to identify potential therapeutic targets based on changes in immunological factors (including natural killer cells, macrophages, the complement system, miRNA and P‑selectin) in the ectopic endometrial tissue. It is hoped that this work can be used as the basis for identifying accurate diagnostic markers for EM and developing personalized immune‑targeted therapy.

Spatial transcriptomic analysis identifies epithelium-macrophage crosstalk in endometriotic lesions

The mechanisms underlying the pathophysiology of endometriosis, characterized by the presence of endometrium-like tissue outside the uterus, remain poorly understood. This study aimed to identify cell type-specific gene expression changes in superficial peritoneal endometriotic lesions and elucidate the crosstalk among the stroma, epithelium, and macrophages compared to patient-matched eutopic endometrium. Surprisingly, comparison between lesions and eutopic endometrium revealed transcriptional similarities, indicating minimal alterations in the sub-epithelial stroma and epithelium of lesions. Spatial transcriptomics highlighted increased signaling between the lesion epithelium and macrophages, emphasizing the role of the epithelium in driving lesion inflammation. We propose that the superficial endometriotic lesion epithelium orchestrates inflammatory signaling and promotes a pro-repair phenotype in macrophages, providing a new role for complement 3 in lesion pathobiology. This study underscores the significance of considering spatial context and cellular interactions in uncovering mechanisms governing disease in endometriotic lesions.

Reprogramming peritoneal macrophages with outer membrane vesicle-coated PLGA nanoparticles for endometriosis prevention

Endometriosis is a chronic inflammatory disease that primarily affects women of reproductive age. The current hormonal treatments are unsuitable for women who wish to conceive, highlighting the need for non-hormonal therapeutic alternatives. In this study, we engineered outer membrane vesicle (OMV)-coated poly (lactic-co-glycolic acid) (PLGA) nanoparticles (OMV-NPs) as a potential therapy for endometriosis. These OMV-NPs were internalized by macrophages more efficiently than bacterial OMVs and preserved the immunostimulatory properties of OMVs. In vivo administration of OMV-NPs in mice achieved prolonged retention in the peritoneal cavity, with effective uptake by nearly 80 % of the peritoneal macrophages. Notably, treatment with OMV-NPs reprogrammed macrophages toward the M1 phenotype, resulting in a significant decrease in the M2 to M1 ratio within the peritoneal cavity and in endometriotic lesions. This shift from M2 to M1 was associated with reduced TGF-β1 production and suppressed myofibroblast activation, which led to substantial inhibition of endometriosis progression. Furthermore, immunohistochemical imaging of paired eutopic and ectopic endometrial tissues from endometriosis patients revealed a positive correlation between M2-polarized macrophages and fibrosis. This finding suggests that reprogramming macrophages with OMV-NPs could be a promising therapeutic approach for endometriosis.

Identification of distinct stool metabolites in women with endometriosis for non-invasive diagnosis and potential for microbiota-based therapies

BACKGROUND

Endometriosis, a poorly studied gynecological condition, is characterized by the presence of ectopic endometrial lesions resulting in pelvic pain, inflammation, and infertility. These associated symptoms contribute to a significant burden, often exacerbated by delayed diagnosis. Current diagnostic methods involve invasive procedures, and existing treatments provide no cure.

METHODS

Microbiome-metabolome signatures in stool samples from individuals with and without endometriosis were determined using unbiased metabolomics and 16S bacteria sequencing. Functional studies for selected microbiota-derived metabolites were conducted in vitro using patient-derived cells and in vivo by employing murine and human xenograft pre-clinical disease models.

FINDINGS

We discovered a unique bacteria-derived metabolite signature intricately linked to endometriosis. The altered fecal metabolite profile exhibits a strong correlation with that observed in inflammatory bowel disease (IBD), revealing intriguing connections between these two conditions. Notably, we validated 4-hydroxyindole, a gut-bacteria-derived metabolite that is lower in stool samples of endometriosis. Extensive in vivo studies found that 4-hydroxyindole suppressed the initiation and progression of endometriosis-associated inflammation and hyperalgesia in heterologous mouse and in pre-clinical models of the disease.

CONCLUSIONS

Our findings are the first to provide a distinct stool metabolite signature in women with endometriosis, which could serve as stool-based non-invasive diagnostics. Further, the gut-microbiota-derived 4-hydroxyindole poses as a therapeutic candidate for ameliorating endometriosis.

FUNDING

This work was funded by the NIH/NICHD grants (R01HD102680, R01HD104813) and a Research Scholar Grant from the American Cancer Society to R.K.

P2X4 receptor mediates macrophage infiltration leading to endometriotic cyst epithelium proliferation and hyperalgesia in mouse model

OBJECTIVE

To evaluate the effects of a P2X4 receptor (P2X4R)-specific antagonist on murine endometriotic-like lesions and human endometriotic stromal cells.

DESIGN

Experimental study using an in vivo mouse endometriosis model and in vitro primary culture of human endometriotic stromal cells. NC-2600, an antagonist of the P2X4 ionotropic ATP receptor (P2X4R), was orally administered to the mice and cells. Gene expression analyses for cytokines were conducted in the endometriotic-like cysts and vaginal portion of mice, and immunohistochemistry was performed to evaluate the proliferative activity and localization of macrophages in addition to cytokine expression. The sensation of murine vaginal pain was evaluated using visceromotor responses.

RESULTS

NC-2600 reduced the proliferation of the cyst epithelium and vaginal pain sensation. In both cysts and vaginas, P2X4R is mainly expressed in macrophages, and NC-2600 reduces the number of tissue macrophages and reverses the elevated expression of InterleukinL-33 and cyclooxygenase-2 in animals with endometriosis.

CONCLUSION

These results indicate unknown pathophysiological roles of P2X4R expressed in local macrophages at the injury site of endometriosis and in the vagina, suggesting the potential therapeutic effects of orally administered P2X4R inhibitors for alleviating the symptoms of endometriosis.

Bioinformatic Analysis of m6A Regulator-Mediated RNA Methylation Modification Patterns and Immune Microenvironment Characterization in Endometriosis

Epigenetic regulation plays an essential role in immunity and inflammation in endometriosis. In this study, we aimed to explore differences in m6A regulators between endometriosis patients and normal women and analyze the effect of m6A modification on immune and inflammatory microenvironment. The samples for analysis were downloaded from the Gene Expression Omnibus database, including ectopic endometrium (EC), eutopic endometrium (EU), and normal eutopic endometrium (NM) samples from non-endometriosis women. The validation process involved utilizing our previous RNA-sequencing data. Subsequently, a correlation analysis was performed to ascertain the relationship between m6A and the inflammatory microenvironment profile, encompassing infiltrating immunocytes, immune-inflammation reaction gene sets, and human leukocyte antigen genes. LASSO analyses were used to develop risk signature. The findings of this study indicate that the m6A regulators FTO were observed to be significantly up-regulated, while YTHDF2, CBLL1, and METTL3 were down-regulated in endometriosis tissues. The CIBERSORT analysis revealed that the local inflammatory microenvironment of ectopic lesions plays a crucial role in the development of endometriosis. Notably, M2 macrophages exhibited a significant difference between the EC and NM groups. Moreover, M2 macrophages demonstrated a positive correlation with FTO (0.39) and a negative correlation with CBLL1 (- 0.35). Furthermore, consistent clustering of EC and EU samples resulted in the identification of three distinct cell subtypes. Among different cell subtypes, significant differences were in immunoinfiltrating cells, plasma cells, naive CD4 T cells, memory activated CD4 T cells, gamma delta T cells, resting NK cells and activated NK cells but not in macrophages. Furthermore, the identification of various compounds capable of targeting these m6A genes was achieved. In conclusions, our integrated bioinformatics analysis results demonstrated that m6A-related genes METTL3, CBLL1 and YTHDF2 may be useful biomarkers for endometriosis in ectopic endometrium. The potential therapeutic approach of targeting m6A regulators holds promise for the treatment of endometriosis.

Efferocytosis and infertility: Implications for diagnosis and therapy

Recent research has shed light on the intricate connection between efferocytosis and infertility, revealing its dysregulation as a contributing factor in various reproductive diseases. Despite the multifaceted nature of infertility etiology, the impact of insufficient clearance of apoptotic cells on fertility has emerged as a focal point. Notably, the removal of apoptotic cells through phagocytosis in the female reproductive system has been a subject of extensive investigation in the field of infertility. Additionally, special functions performed by immune system cell types, such as macrophages and Sertoli cells, in the male reproductive system underscore their significance in spermatogenesis and the efferocytosis of apoptotic germ cells. Dysregulation of efferocytosis emerges as a critical factor contributing to reproductive challenges, such as low pregnancy rates, miscarriages, and implantation failures. Moreover, defective efferocytosis can lead to compromised implantation, recurrent miscarriages, and unsuccessful assisted reproductive procedures. This review article aims to provide a comprehensive overview of efferocytosis in the context of infertility. Molecular mechanisms underlying efferocytosis, its relevance in both female and male infertility, and its implications in various reproductive diseases are elucidated. The elucidation of the intricate relationship between efferocytosis and infertility not only facilitates diagnosis but also paves the way for targeted therapeutic interventions.

Utilizing AI for the Identification and Validation of Novel Therapeutic Targets and Repurposed Drugs for Endometriosis

Endometriosis affects over 190 million women globally, and effective therapies are urgently needed to address the burden of endometriosis on women's health. Using an artificial intelligence (AI)-driven target discovery platform, two unreported therapeutic targets, guanylate-binding protein 2 (GBP2) and hematopoietic cell kinase (HCK) are identified, along with a drug repurposing target, integrin beta 2 (ITGB2) for the treatment of endometriosis. GBP2, HCK, and ITGB2 are upregulated in human endometriotic specimens. siRNA-mediated knockdown of GBP2 and HCK significantly reduced cell viability and proliferation while stimulating apoptosis in endometrial stromal cells. In subcutaneous and intraperitoneal endometriosis mouse models, siRNAs targeting GBP2 and HCK notably reduced lesion volume and weight, with decreased proliferation and increased apoptosis within lesions. Both subcutaneous and intraperitoneal administration of Lifitegrast, an approved ITGB2 antagonist, effectively suppresses lesion growth. Collectively, these data present Lifitegrast as a previously unappreciated intervention for endometriosis treatment and identify GBP2 and HCK as novel druggable targets in endometriosis treatment. This study underscores AI's potential to accelerate the discovery of novel drug targets and facilitate the repurposing of treatment modalities for endometriosis.

Multiple lesion inductions intensify central sensitization driven by neuroinflammation in a mouse model of endometriosis

Introduction

Endometriosis is an inflammatory disease associated with chronic pelvic pain (CPP). Growing evidence indicates that endometriotic lesions are not the sole source of pain. Instead, central nervous system (CNS) dysfunction created by prolonged peripheral and central sensitization plays a role in developing endometriosis-associated CPP. This study investigated how CPP is established using a multiple lesion induction mouse model of endometriosis, as repeated retrograde menstruation is considered underlying endometriosis pathogenesis.

Methods

We generated endometriosis-like lesions by injecting endometrial tissue fragments into the peritoneal cavity in mice. The mice received a single (1x) or multiple inductions (6x) to simulate recurrent retrograde menstruation. Lesion development, hyperalgesia by behavioral testing, signs of peripheral sensitization, chronic inflammation, and neuroinflammation were examined with lesions, peritoneal fluids, dorsal root ganglia (DRG), spinal codes, and brain.

Results

Multiple lesion inductions increased lesion numbers and elevated abdominal and hind paw hypersensitivity compared to single induction mice. Elevated persistent glial cell activation across several brain regions and/or spinal cords was found in the multiple induction mice. Specifically, IBA1+ microglial soma size was increased in the hippocampus and thalamus. IBA1+ cells were abundant in the cortex, hippocampus, thalamus, and hypothalamus of the multiple induction mice. GFAP+ astrocytes were mainly elevated in the hippocampus. Elevated TRPV1, SP, and CGRP expressions in the DRG were persistent in the multiple induction mice. Furthermore, multiple inductions induced the severe disappearance of TIM4hi MHCIIlo residential macrophages and the influx of increased proinflammatory TIM4lo MHCIIhi macrophages in the peritoneal cavity. The single and multiple inductions elevated secreted TNFα, IL-1β, and IL-6 levels in the peritoneal cavity at 2 weeks. Elevated cytokine levels returned to the pre-induction levels in the single induction mice at 6 weeks; however, they remained elevated in the multiple induction mice.

Conclusions

Our results indicate that the repeatedly occurring lesion inductions (=mimic retrograde menstruation) can be a peripheral stimulus that induces nociceptive pain and creates composite chronic inflammatory stimuli to cause neuroinflammation and sensitize the CNS. The circuits of neuroplasticity and stimulation of peripheral organs via a feedback loop of neuroinflammation may mediate widespread endometriosis-associated CPP.

Association between the C-reactive protein-triglyceride-glucose index and endometriosis: a cross-sectional study using data from the national health and nutrition examination survey, 1996-2006

BACKGROUND

The C-reactive protein-triglyceride glucose index (CTI) is a promising new marker for evaluating the severity of inflammation. Endometriosis (EM) is a prevalent chronic inflammatory condition influenced by estrogen, primarily affecting women of reproductive age. However, no study has demonstrated an association between the CTI and EM.

METHODS

This cross-sectional study sourced data from females 20-50 years of age from the National Health and Nutrition Examination Survey (NHANES) 1996-2006, and included those with self-reported diagnoses of EM and sufficient information to calculate the CTI, computed as 0.412 × ln (C-reactive protein [CRP]) + ln (triglycerides [mg/dL] × fasting plasma glucose [mg/dL]/2). Multivariate logistic regression, restricted cubic splines, and subgroup analyses were performed to examine the association between the CTI and EM.

RESULTS

Data from 2235 women (175 [7.82%] with EM, 2060 [92.18%] without EM [controls]), were included: those with EM exhibited a tendency toward higher CTI (p = 0.005), and CTI was positively associated with the prevalence of EM (p = 0.011). In Model 1, a 1 mg/dL increment in CTI was associated with a 56% higher prevalence of EM (odds ratio [OR] 1.563 [95% confidence interval (CI) 1.295-1.885]; P < 0.001). This association in Model 2 (OR 1.609 [95% CI 1.334-1.941]; p < 0.001) and Model 3 (OR 1.565 [95% CI 1.246-1.966]; p < 0.001) remained significant. Notably, individuals in the uppermost remnant cholesterol tertile exhibited a notably higher prevalence of EM than those in the lowest tertile (OR 3.029, p = 0.051). Restricted cubic splines revealed a nonlinear positive association between CTI and the prevalence of EM. In addition, greater EM prevalence was observed with CTI in those > 40 years of age (OR 1.57 [95% CI 1.16-2.13]), body mass index ≥ 25 kg/m2 (OR 1.38 [95% CI 1.06-1.80]), smoking ≥ 100 cigarettes (OR 1.43 [95% CI 1.06-1.96]), married or living with partner (OR 1.41 [95% CI 1.09-1.85]), and oral contraceptive use (OR 1.35 [95% CI 1.07-1.69]).

CONCLUSIONS

CTI was positively associated with EM in women in the United States. Use of the CTI as an indicator of inflammation may provide new insights for the prevention and management of EM.

Decreased CCL5 expression in endometrial stromal cells induces deficient CCR5 +CD4 + T cells in endometriosis

Endometriosis (EMS) is a benign gynecological disease characterized by the growth of endometrial tissue outside the uterine cavity. Evidence shows that the survival of patients with ectopic endometrial implants is associated with a dysregulated immune microenvironment. CD4 + T cells can regulate EMS through diverse cytokines, the inflammatory response, and angiogenesis. CCR5 +CD4 + T cells exhibit increased cellular immunogenicity and play a role in infectious diseases, host defense, and cancer progression. However, the specific mechanisms of CCR5 +CD4 + T cells in EMS remain unknown. In the present study, flow cytometry and RNA-seq are utilized to assess the proportions and features of CCR5 +CD4 + T cells in EMS patients, RT-PCR and ELISA are used to assess the production of CCL5 by ectopic endometrial stromal cells (ecESCs). Two EMS models are established through C57B6 wild-type and CCL5 ‒/‒ mice and utilized to explore the in vivo effects of CCR5 +CD4 + T cells on ectopic lesions. Compared with CCR5 ‒CD4 + T cells, CCR5 +CD4 + T cells display a more activated and cytotoxic phenotype. Diminished CCR5 +CD4 + T cells and their impaired ability to produce IFN-γ are observed in the ectopic lesions of EMS patients and in murine EMS models. Impaired production of CCL5 has been detected in human ecESCs. Moreover, endometria stripped from CCL5 ‒/‒ mice are more likely to generate ectopic lesions in the peritoneum of recipient mice. These findings demonstrate that the attenuated recruitment of CCR5 + CD4 + T cells in ectopic lesions caused by decreased production of CCL5 in ecESCs may facilitate the progression of EMS.

The Estrogen-Immune Interface in Endometriosis

Endometriosis is a gynecologic condition characterized by the growth of endometrium-like stroma and glandular elements outside of the uterine cavity. The involvement of hormonal dysregulation, specifically estrogen, is well established in the initiation, progression, and maintenance of the condition. Evidence also highlights the association between endometriosis and altered immune states. The human endometrium is a highly dynamic tissue that undergoes frequent remodeling in response to hormonal regulation during the menstrual cycle. Similarly, endometriosis shares this propensity, compounded by unclear pathogenic mechanisms, presenting unique challenges in defining its etiology and pathology. Here, we provide a lens to understand the interplay between estrogen and innate and adaptive immune systems throughout the menstrual cycle in the pathogenesis of endometriosis. Estrogen is closely linked to many altered inflammatory and immunomodulatory states, affecting both tissue-resident and circulatory immune cells. This review summarizes estrogenic interactions with specific myeloid and lymphoid cells, highlighting their implications in the progression of endometriosis.

Unlocking the Potential: How Flavonoids Affect Angiogenesis, Oxidative Stress, Inflammation, Proliferation, Invasion, and Alter Receptor Interactions in Endometriosis

Endometriosis, though not classified as a carcinogenic condition, shares features such as oxidative stress, migration, invasion, angiogenesis, and inflammation with tumor cells. This study aims to review the effects of flavonoids on these processes and their molecular mechanisms in preventing and treating endometriosis. A comprehensive review was conducted, involving a literature search in online databases using keywords like "endometriosis," "endometrioma," and "flavonoid." Two authors screened the literature based on predefined criteria, and the selected studies were summarized in a structured data extraction table. Studies reviewed showed that various flavonoids impact key processes in endometriosis, including angiogenesis, inflammation, oxidative stress, and invasiveness. Flavonoids such as 2',7'-dichlorodihydrofluorescein diacetate (H2DCF-DA), naringenin, apigenin, myricetin, 5,7-dimethoxyflavone (DMF), chrysin, and 6,8-diprenylorobol were found to induce oxidative stress. Xanthohumol, isoliquiritigenin, and luteolin demonstrated effects on angiogenesis. Apigenin, isoliquiritigenin, and luteolin exhibited anti-inflammatory properties. Additionally, 3,6-dihydroxyflavone, isoliquiritigenin, and naringenin displayed anti-invasive activities. Flavonoid-receptor interactions further enhance their therapeutic potential in endometriosis management. Flavonoids such as nobiletin, chrysin, and daidzein modulate PPARγ and PPARα, reducing inflammation, promoting apoptosis, and improving lipid metabolism. These interactions regulate critical pathways in angiogenesis and immune responses. Additionally, flavonoids impact the aryl hydrocarbon receptor (AhR), with compounds like resveratrol inhibiting cell proliferation and cholesterol biosynthesis, further suppressing lesion growth. The ability of flavonoids like quercetin and kaempferol to antagonize NR4A1 leads to reduced cell proliferation and oxidative stress in endometriotic tissues. These findings offer insights into the mechanisms through which specific flavonoids modulate angiogenesis, inflammation, oxidative stress, and invasiveness in endometriosis. By targeting receptors such as PPARs, AhR, and NR4A1, flavonoids demonstrate the capacity to modulate both metabolic and inflammatory pathways, offering a multifaceted approach to managing endometriosis. Flavonoids can selectively target pathophysiologic molecules and pathways implicated in the condition. Consequently, leveraging the therapeutic attributes of flavonoids could lead to novel strategies for managing endometriosis.

Female reproductive disease, endometriosis: From inflammation to infertility

Despite the fact that endometriosis is a common gynecological disease that occurs in 10% of women of reproductive age, the pathogenesis and treatment strategy are not clear to date. Endometriosis patients are commonly characterized by adhesions in the pelvis or ovaries, which leads to prolonged inflammation in the abdominal cavity. To handle the chronic inflammation, changes of immune cells, including T cells, NK cells, and macrophage, are accompanied. Therefore, diverse cytokines and adhesions of the abdominal cavity lead to poor quality of ovarian follicles, inappropriate response to the hormone, and infertility. This review will guide researchers to summarize the molecular changes and identify new treatment strategies for endometriosis-mediated inflammation and pregnancy failure.

The Effect of Endometriosis on In Vitro Fertilization Outcomes: A Systematic Review and Meta-Analysis

OBJECTIVES

The purpose of this study was to evaluate the impact of endometriosis on various outcomes of in vitro fertilization (IVF), including live birth rates, clinical pregnancy rates, fertilization rates, and implantation rates, through a systematic review and meta-analysis.

METHODS

Systematic searches were carried out using PubMed, MEDLINE, Cochrane Central Register of Controlled Trials, Scopus, EMBASE, and Web of Science from January 2010 to November 2023. Studies comparing IVF outcomes in women with and without endometriosis were included. The primary outcome was live birth rate; secondary outcomes included clinical pregnancy, fertilization, and implantation rates. Data were extracted and analyzed using odds ratio (OR) and 95% confidence interval (CI) with fixed or random-effects models, depending on heterogeneity.

RESULTS

From 1340 studies initially identified, 40 studies met the inclusion criteria, encompassing 8970 women with endometriosis and 42,946 control participants. There were no significant differences between the endometriosis and control groups in terms of live birth rate (OR 1.03, 95% CI 0.75-1.41, p = 0.84), clinical pregnancy rate (OR 0.86, 95% CI 0.72-1.02, p = 0.1), or fertilization rate (OR 0.96, 95% CI 0.79-1.15, p = 0.64). However, endometriosis was associated with a significantly lower implantation rate (OR 0.85, 95% CI 0.74-0.97, p = 0.02).

CONCLUSIONS

Endometriosis significantly negatively affects implantation rates in women undergoing IVF, despite the absence of significant differences in live birth, clinical pregnancy, and fertilization rates. Further research is needed to evaluate the impact of different stages of endometriosis on IVF outcomes and to develop optimized management protocols for these patients.

The role and potential treatment of macrophages in patients with infertility and endometriosis

Endometriosis is characterized as a macrophage-related ailment due to its strong link with immune dysfunction. Understanding the status of macrophage polarization in the context of endometriosis-related infertility is crucial for advancing diagnostic and therapeutic strategies. Our comprehensive review delves into the foundational understanding of macrophages and their profound influence on both endometriosis and infertility. Additionally, we illuminate the complex role of macrophages in infertility and endometriosis specifically. Finally, we focused on four critical dimensions: follicular fluid, the intraperitoneal environment, endometrial receptivity, and strategies for managing endometriosis. It is clear that throughout the progression of endometriosis, the diverse polarization states of macrophages play a pivotal role in the internal reproductive environment of infertile individuals grappling with this condition. Modulating macrophage polarization in the reproductive environment of endometriosis patients could address infertility challenges more effectively, offering a promising pathway for treating infertility associated with endometriosis.

Exploring the Shared Pathogenesis Mechanisms of Endometriosis and Cancer: Stemness and Targeted Treatments of Its Molecular Pathways-A Narrative Review

Endometriosis is a benign disease but with malignant behavior, sharing numerous features with cancers. Endometriosis is the development of endometrial tissue outside the uterus, with the presence of both glands and stroma. Approximately 10% of women of reproductive age suffer from endometriosis; it involves high social costs and affects the patient's quality of life. In this review, we attempt to capture the pathogenesis mechanisms that are common to endometriosis and cancer based on molecular biology, focusing more on the principle of immunological changes and stemness. Clinical applicability will consist of targeted treatments that represent future directions in these diseases, which impose a burden on the healthcare system. Unlike endometriosis, cancer is a disease with fatal evolution, with conventional treatment based on chemo/radiotherapy. Here, we focus on the niche of personalized treatments that target molecular pathways. Our findings show that, in both pathologies, the resistance to treatments is due to the stemness of the stem cells, which might play a role in the appearance and evolution of both diseases. More research is needed before we can draw firm conclusions.

Targeting delivery of mifepristone to endometrial dysfunctional macrophages for endometriosis therapy

Endometriosis seriously affects 6-10 % of reproductive women globally and poses significant clinical challenges. The process of ectopic endometrial cell colonization shares similarities with cancer, and a dysfunctional immune microenvironment, characterized by non-classically polarized macrophages, plays a critical role in the progression of endometriosis. In this study, a targeted nano delivery system (BSA@Mif NPs) was developed using bovine serum albumin (BSA) as the carrier of mifepristone. The BSA@Mif NPs were utilized to selectively target M2 macrophages highly enriched in ectopic endometrial tissue via the SPARC receptor. This targeting strategy increases drug concentration at ectopic lesions while minimizing its distribution to normal tissue, thereby reducing side effects. In vitro studies demonstrated that BSA@Mif NPs not only enhanced the cellular uptake of M2-type macrophages and ectopic endometrial cells but also improved the cytotoxic effect of mifepristone on ectopic endometrial cells. Furthermore, the BSA@Mif NPs effectively induced immunogenic cell death (ICD) in ectopic endometrial cells and repolarized M2-type macrophages toward the M1 phenotype, resulting in a synergistic inhibition of ectopic endometrial cell growth. In vivo experiments revealed that BSA@Mif NPs exhibited significant therapeutic efficacy in endometriosis-bearing mice by increasing drug accumulation in the endometriotic tissues and modulating the immune microenvironment. This targeted biomimetic delivery strategy presents a promising approach for the development of endometriosis-specific therapies based on existing drugs. STATEMENT OF SIGNIFICANCE: Macrophages play an essential role in immune dysfunctional microenvironment promoting the occurrence and progression of endometriosis and can be a crucial target for developing immune microenvironment regulation strategies for the unmet long-term management of endometriosis. The albumin nanoparticles constructed based on SPARC overexpression in macrophages and endometrial cells and albumin biosafety can achieve the targeted therapy of endometriosis by increasing the passive- and active-mediated drug accumulation in ectopic endometrium and remodeling the immune microenvironment based on macrophage regulation. This study has the following implications: i) overcoming the inherent shortcomings of clinical drugs by nanotechnology is an alternative way of developing medication; ii) developing microenvironment modulation strategies based on macrophage regulation for endometriosis management is feasible.

TET3-overexpressing macrophages promote endometriosis

Endometriosis is a debilitating, chronic inflammatory disease affecting approximately 10% of reproductive-age women worldwide with no cure. While macrophages have been intrinsically linked to the pathophysiology of endometriosis, targeting them therapeutically has been extremely challenging due to their high heterogeneity and because these disease-associated macrophages (DAMs) can be either pathogenic or protective. Here, we report identification of pathogenic macrophages characterized by TET3 overexpression in human endometriosis lesions. We show that factors from the disease microenvironment upregulated TET3 expression, transforming macrophages into pathogenic DAMs. TET3 overexpression stimulated proinflammatory cytokine production via a feedback mechanism involving inhibition of let-7 miRNA expression. Remarkably, these cells relied on TET3 overexpression for survival and hence were vulnerable to TET3 knockdown. We demonstrated that Bobcat339, a synthetic cytosine derivative, triggered TET3 degradation in both human and mouse macrophages. This degradation was dependent on a von Hippel-Lindau (VHL) E3 ubiquitin ligase whose expression was also upregulated in TET3-overexpressing macrophages. Furthermore, depleting TET3-overexpressing macrophages either through myeloid-specific Tet3 ablation or using Bobcat339 strongly inhibited endometriosis progression in mice. Our results defined TET3-overexpressing macrophages as key pathogenic contributors to and attractive therapeutic targets for endometriosis. Our findings may also be applicable to other chronic inflammatory diseases where DAMs have important roles.

Resveratrol and Its Natural Analogs Mitigate Immune Dysregulation and Oxidative Imbalance in the Endometriosis Niche Simulated in a Co-Culture System of Endometriotic Cells and Macrophages

Background: Inflammation and immune cell dysfunction are critical facilitators of endometriosis pathophysiology. Macrophages are renowned for stimulating lesion growth, vascularization, innervation, and pain generation. By combining macrophages and endometriotic cells, we determined if resveratrol and its natural analogs can target the immune dysregulation and oxidative imbalance in endometriosis. Methods: After treatment with compounds (5, 10, 25 µM), we evaluated the expression of key inflammatory and oxidative stress markers, cytokines release, and ROS production by applying q-PCR, ELISA, Cytometric Beads Array, and multiplexed fluorogenic staining and flow cytometry analysis with bioimaging. Results: The results showed that endometriosis-related macrophages treated with stilbenes have impaired expression of pro-inflammatory markers (IL6, IL8, IL1B, TNF, CCL2, CXCL10, PTGS2). The effect of resveratrol, pterostilbene, and piceatannol was observed, especially in reducing IL1B, CCL2, and CXCL10 genes up to 3.5-, 5-, and 7.7-fold at 25 µM, respectively. Also, with piceatannol or polydatin exposure, the IL-6 decrease was noticeable. This study reported an antioxidant effect by reducing ROS-positive cells from 96% to 48% by pterostilbene. Results from flow cytometry correlated with the transcript activation of detoxification enzymes (SOD, GPX). Conclusions: Prospects for potential therapy based on regulating the immune microenvironment and reducing the accumulation of free radicals with stilbenes application were described in the article.

Mpox infection of stromal cells and macrophages of macaque with endometriosis

The mpox outbreak of 2022-2023 represented a new global health challenge and recognition of mpox as a sexually transmitted disease. The majority of cases were reported in men who have sex with men (MSM), but women are also susceptible, especially during pregnancy. We evaluated the reproductive tracts of a subset of macaques from a large rechallenge study of mpox infection with virus from the 2022 outbreak and identified intraabdominal mpox replication associated with endometriosis. Mpox virus (MPXV) was found not only in skin, but in the cervix, the uterus, and periovarian endometriotic lesions of the affected macaque. Mpox replication preferentially targeted vimentin-positive poorly differentiated endometriotic stromal tissue and infiltrating macrophages in the reproductive tract. Mpox tropism for stromal cells and macrophages has broad implications for mpox pathogenesis and associated clinical syndromes. In addition, women with endometriosis may be at heightened risk for adverse outcomes associated with mpox infection. The rhesus macaque provides rare insight into this disease and the potential complications of mpox infection in the context of genitourinary tract disease.

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.

The vicious cycle of chronic endometriosis and depression-an immunological and physiological perspective

Endometriosis is a chronic, estrogen-dependent, proinflammatory disease that can cause various dysfunctions. The main clinical manifestations of endometriosis include chronic pelvic pain and impaired fertility. The disease is characterized by a spectrum of dysfunctions spanning hormonal signaling, inflammation, immune dysregulation, angiogenesis, neurogenic inflammation, epigenetic alterations, and tissue remodeling. Dysregulated hormonal signaling, particularly involving estrogen and progesterone, drives abnormal growth and survival of endometrial-like tissue outside the uterus. Chronic inflammation, marked by immune cell infiltration and inflammatory mediator secretion, perpetuates tissue damage and pain. Altered immune function, impaired ectopic tissue clearance, and dysregulated cytokine production contribute to immune dysregulation. Enhanced angiogenesis promotes lesion growth and survival. Epigenetic modifications influence gene expression patterns, e.g., HSD11B1 gene, affecting disease pathogenesis. Endometriosis related changes and infertility lead to depression in diagnosed women. Depression changes lifestyle and induces physiological and immunological changes. A higher rate of depression and anxiety has been reported in women diagnosed with endometriosis, unleashing physiological, clinical and immune imbalances which further accelerate chronic endometriosis or vice versa. Thus, both endometriosis and depression are concomitantly part of a vicious cycle that enhance disease complications. A multidimensional treatment strategy is needed which can cater for both endometrial disease and depression and anxiety disorders.

Endometriotic tissue fragments are viable after cryopreservation in an ex vivo tissue model recapitulating the fibrotic microenvironment

STUDY QUESTION

Is it possible to establish an ex vivo endometriosis model using cryopreserved endometriotic tissue fragments?

SUMMARY ANSWER

Cryopreserved endometriotic tissue fragments remain viable after thawing and during at least 3 days of culture and can therefore be used to establish an ex vivo endometriosis model to efficiently test potential therapeutic agents.

WHAT IS KNOWN ALREADY

Endometriosis is the most prevalent benign gynecologic disease with an enormous societal burden; however, curative therapies are still lacking. To efficiently test potential new therapies, an ex vivo model based on previously cryopreserved endometriotic tissue that recapitulates the different endometriosis subtypes and their microenvironment is highly desirable.

STUDY DESIGN, SIZE, DURATION

Endometriotic tissue fragments of three different subtypes were obtained from 28 patients by surgical resection. After cryopreservation and thawing, viability and metabolic activity of these tissue fragments were assessed. Viability was compared with fresh fragments from 11 patients directly after surgical removal. Experimental intervention studies were performed in cryopreserved and thawed tissue fragments from two patients to confirm the usability of these tissues for ex vivo intervention studies.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Endometriotic tissue fragments (n = 45) were cryopreserved according to three different protocols. After thawing, fragments were cultured for 24 h. A resazurin-based assay was performed to assess the metabolic activity of the tissue fragments. In addition, cell type-specific viability was analyzed by VivaFix, Hoechst 33342, and α-smooth muscle actin immunofluorescence staining and confocal microscopy. The presence of endometriosis was histologically confirmed based on hematoxylin-eosin staining. Cryopreserved and thawed tissue fragments were treated for 72 h with pirfenidone or metformin and COL1A1 and CEMIP gene expressions were assessed using RT-PCR and RT-qPCR, either in the whole tissue fragments or in myofibroblasts isolated by laser capture microdissection.

MAIN RESULTS AND THE ROLE OF CHANCE

Metabolic activity of endometriotic tissue fragments obtained from peritoneal (PER), ovarian (OMA), and deep (DE) endometriotic lesions was well preserved after cryopreservation in a dimethyl sulfoxide-based medium and was comparable with fresh tissue fragments. Relative metabolic activity compared to fresh tissue was 70% (CI: 92-47%) in PER, 43% (CI: 53-15%) in OMA and 94% (CI: 186-3%) in DE lesions. In fragments from PE lesions 92% (CI: 87-96%), from OMA lesions 95% (CI: 91-98%), and from DE lesions 88% (CI: 78-98%) of cells were viable after cryopreservation and thawing followed by a 24-h culture period. Differences in gene expression of fibrotic markers COL1A1 and CEMIP after 72-h treatment with pirfenidone or metformin could be detected in whole tissue fragments and in isolated myofibroblasts, indicating that cryopreserved and thawed endometriotic tissue fragments are suitable for testing anti-fibrotic interventions.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Viability and metabolic activity of the endometriotic tissue fragments may have been partially compromised by damage sustained during the surgical procedure, contributing to inter-sample variance.

WIDER IMPLICATIONS OF THE FINDINGS

The storage of viable endometriotic tissue fragments for later usage in an ex vivo model creates the possibility to efficiently test potential new therapeutic strategies and facilitates the exchange of viable endometriotic tissue between different research laboratories.

STUDY FUNDING/COMPETING INTEREST(S)

This study was not financially supported by external funding. The authors declare no competing interest.

TRIAL REGISTRATION NUMBER

N/A.

M1 macrophages as promising agents for cell therapy of endometriosis

Endometriosis is a chronic estrogen-dependent disease characterized by the presence of endometrial glands and stroma outside their normal anatomical location. While laparoscopic removal of foci remains the gold standard therapy, it has limited efficacy and certain risks. However, cell therapy using pro-inflammatory M1 macrophages presents a promising and minimally invasive alternative for treating endometriosis. This approach showcases the potential for innovative and effective treatments for this condition. This study aims to explore the anti-endometriosis properties of M1 macrophages. A reproducible syngeneic mouse model of endometriosis was utilized, revealing that formed foci are primarily composed of macrophages with an anti-inflammatory M2 phenotype rather than M1 macrophages. To investigate further, chemically reprogrammed M1 macrophages were labeled with the membrane fluorescent tag PKH26 and administered to animals with endometriosis. Therapy resulted in a decrease in the number and size of foci, accompanied by a shift in the phenotypic composition of peritoneal macrophages. Specifically, the content of M2 macrophages decreased while that of M1 macrophages increased, resembling the composition of healthy animals. Our study conclusively demonstrates the anti-endometriosis properties of M1 macrophages, providing a strong foundation for future research in the cell therapy of endometriosis.

The involvement of peritoneal GATA6+ macrophages in the pathogenesis of endometriosis

Endometriosis is a chronic inflammatory disease that causes debilitating pelvic pain in women. Macrophages are considered to be key players in promoting disease progression, as abundant macrophages are present in ectopic lesions and elevated in the peritoneum. In the present study, we examined the role of GATA6+ peritoneal macrophages on endometriosis-associated hyperalgesia using mice with a specific myeloid deficiency of GATA6. Lesion induction induced the disappearance of TIM4hi MHCIIlo residential macrophages and the influx of increased Ly6C+ monocytes and TIM4lo MHCIIhi macrophages. The recruitment of MHCIIhi inflammatory macrophages was extensive in Mac Gata6 KO mice due to the severe disappearance of TIM4hi MHCIIlo residential macrophages. Ki67 expression confirmed GATA6-dependent proliferative ability, showing different proliferative phenotypes of TIM4+ residential macrophages in Gata6f/f and Mac Gata6 KO mice. Peritoneal proinflammatory cytokines were elevated after lesion induction. When cytokine levels were compared between Gata6f/f and Mac Gata6 KO mice, TNFα at day 21 in Gata6f/f mice was higher than in Mac Gata6 KO mice. Lesion induction increased both abdominal and hind paw sensitivities. Gata6f/f mice tended to show higher sensitivity in the abdomen after day 21. Elevated expression of TRPV1 and CGRP was observed in the dorsal root ganglia after ELL induction in Gata6f/f mice until days 21 and 42, respectively. These results support that peritoneal GATA6+ macrophages are involved in the recruitment and reprogramming of monocyte-derived macrophages. The extensive recruitment of monocyte-derived macrophages in Mac Gata6 KO mice might protect against inflammatory stimuli during the resolution phase, whereas GATA6 deficiency did not affect lesion initiation and establishment at the acute phase of inflammation. GATA6+ residential macrophages act to sustain local inflammation in the peritoneum and sensitivities in the neurons, reflecting endometriosis-associated hyperalgesia.

Predicting disease recurrence in patients with endometriosis: an observational study

BACKGROUND

Despite surgical and pharmacological interventions, endometriosis can recur. Reliable information regarding risk of recurrence following a first diagnosis is scant. The aim of this study was to examine clinical and survey data in the setting of disease recurrence to identify predictors of risk of endometriosis recurrence.

METHODS

This observational study reviewed data from 794 patients having surgery for pelvic pain or endometriosis. Patients were stratified into two analytic groups based on self-reported or surgically confirmed recurrent endometriosis. Statistical analyses included univariate, followed by multivariate logistic regression to identify risk factors of recurrence, with least absolute shrinkage and selection operator (Lasso) regularisation. Risk-calibrated Supersparse Linear Integer Models (RiskSLIM) and survival analyses (with Lasso) were undertaken to identify predictive features of recurrence.

RESULTS

Several significant features were repeatedly identified in association with recurrence, including adhesions, high rASRM score, deep disease, bowel lesions, adenomyosis, emergency room attendance for pelvic pain, younger age at menarche, higher gravidity, high blood pressure and older age. In the surgically confirmed group, with a score of 5, the RiskSLIM method was able to predict the risk of recurrence (compared to a single diagnosis) at 95.3% and included adenomyosis and adhesions in the model. Survival analysis further highlighted bowel lesions, adhesions and adenomyosis.

CONCLUSIONS

Following an initial diagnosis of endometriosis, clinical decision-making regarding disease management should take into consideration the presence of bowel lesions, adhesions and adenomyosis, which increase the risk of endometriosis recurrence.

Association between endometriosis and arthritis: results from NHANES 1999-2006, genetic correlation analysis, and Mendelian randomization study

Background

Previous studies reported that endometriosis may have a higher risk of arthritis. However, it remains unclear whether the association between endometriosis and arthritis has genetic correlations, or the relationship is causal. Linkage Disequilibrium Score (LDSC) and Mendelian Randomization (MR) analyses use genetic variation as a natural experiment to explore genetic correlations and causal inferences from observational data, reducing unmeasured confounding factors.

Method

Participants (aged 20-54 years, n = 2,915) for the cross-sectional study were obtained from the National Health and Nutrition Examination Survey (NHANES). Endometriosis and arthritis were diagnosed based on self-reported by reproductive health and medical condition questionnaire. Weighted multivariable logistic regression was used to explore the relationship between endometriosis and arthritis. LDSC and MR analysis were performed using the genome-wide association study (GWAS) summary statistics to identify the causal association.

Result

A significant positive association between endometriosis and arthritis was found after multivariable adjustment (OR = 1.89; 95% CI: 1.33, 2.67). When exploring different types of arthritis, a positive association was revealed with rheumatoid arthritis (RA), other types of arthritis, and cases that the arthritis type were unknown, with an OR of 2.07 (95% CI: 1.03, 4.17), 2.78 (95% CI: 1.30, 5.95), and 2.06 (95% CI: 1.36, 3.11), respectively. However, genetic correlation analysis between endometriosis and RA did not reveal any significant findings (all P values > 0.05). Moreover, MR analysis also failed to identify a causal relationship between endometriosis and RA (all P values > 0.05).

Conclusion

Cross-sectional study identified a significant positive association between endometriosis and arthritis among US women, especially among RA, while findings based on LDSC and MR analysis did not support a genetic correlation or causal role. These findings suggest that clinicians should pay more attention to the coexistence of RA in endometriosis patients and explore the shared pathophysiological mechanisms of these two disorders, with a particular focus on extrinsic factors rather than intrinsic genetic inheritance.

Altered Monocyte and Lymphocyte Phenotypes Associated with Pathogenesis and Clinical Efficacy of Progestogen Therapy for Peritoneal Endometriosis in Adolescents

Background: Immunological imbalances characteristic of endometriosis may develop as early as the primary manifestations of the disease in adolescence. Objective: To evaluate subpopulation dynamics of monocytes and lymphocytes in peripheral blood and peritoneal fluid of adolescents with peritoneal endometriosis at diagnosis and after 1-year progestogen therapy. Methods: This study included 70 girls, 13-17 years old, diagnosed laparoscopically with peritoneal endometriosis (n = 50, main group) or paramesonephric cysts (n = 20, comparison group). Phenotypes of monocytes and lymphocytes of the blood and macrophages of the peritoneal fluid were analyzed by flow cytometry at diagnosis and during progestogen therapy. Results: Differential blood counts of CD16+ (p < 0.001) and CD86+ (p = 0.017) monocytes were identified as independent risk factors for peritoneal endometriosis in adolescents. During the treatment, cytotoxic lymphocytes CD56dimCD16bright (p = 0.049) and CD206+ monocytes (p < 0.001) significantly increased while CD163+ monocytes decreased in number (p = 0.017). The CD56dimCD16bright blood counts before (p < 0.001) and during progestogen therapy (p = 0.006), as well as CD206+ blood counts during the treatment (p = 0.038), were associated with the efficacy of pain relief after 1-year progestogen therapy. Conclusions: Adolescents with peritoneal endometriosis have altered counts of pro- and anti-inflammatory monocytes and lymphocytes both before and after 1-year progestogen therapy, correlating with treatment efficacy and justifying long-term hormonal therapy.

Vaginal and rectal microbiome contribute to genital inflammation in chronic pelvic pain

BACKGROUND

Chronic pelvic pain (CPP) is a multifactorial syndrome that can substantially affect a patient's quality of life. Endometriosis is one cause of CPP, and alterations of the immune and microbiome profiles have been observed in patients with endometriosis. The objective of this pilot study was to investigate differences in the vaginal and gastrointestinal microbiomes and cervicovaginal immune microenvironment in patients with CPP and endometriosis diagnosis compared to those with CPP without endometriosis and no CPP.

METHODS

Vaginal swabs, rectal swabs, and cervicovaginal lavages (CVL) were collected among individuals undergoing gynecologic laparoscopy. Participants were grouped based on patients seeking care for chronic pain and/or pathology results: CPP and endometriosis (CPP-Endo) (n = 35), CPP without endometriosis (n = 23), or patients without CPP or endometriosis (controls) (n = 15). Sensitivity analyses were performed on CPP with endometriosis location, stage, and co-occurring gynecologic conditions (abnormal uterine bleeding, fibroids). 16S rRNA sequencing was performed to profile the microbiome, and a panel of soluble immune mediators was quantified using a multiplex assay. Statistical analysis was conducted with SAS, R, MicrobiomeAnalyst, MetaboAnalyst, and QIIME 2.

RESULTS

Significant differences were observed between participants with CPP alone, CPP-Endo, and surgical controls for body mass index, ethnicity, diagnosis of ovarian cysts, and diagnosis of fibroids. In rectal microbiome analysis, both CPP alone and CPP-Endo exhibited lower alpha diversity than controls, and both CPP groups revealed enrichment of irritable bowel syndrome-associated bacteria. CPP-Endo exhibited an increased abundance of vaginal Streptococcus anginosus and rectal Ruminococcus. Patients with CPP and endometrioma (s) demonstrated increased vaginal Streptococcus, Lactobacillus, and Prevotella compared to other endometriosis sites. Further, abnormal uterine bleeding was associated with an increased abundance of bacterial vaginosis-associated bacteria. Immunoproteomic profiles were distinctly clustered by CPP alone and CPP-Endo compared to controls. CPP-Endo was enriched in TNF⍺, MDC, and IL-1⍺.

CONCLUSIONS

Vaginal and rectal microbiomes were observed to differ between patients with CPP alone and CPP with endometriosis, which may be useful in personalized treatment for individuals with CPP and endometriosis from those with other causes of CPP. Further investigation is warranted in patients with additional co-occurring conditions, such as AUB/fibroids, which add additional complexity to these conditions and reveal the enrichment of distinct pathogenic bacteria in both mucosal sites. This study provides foundational microbiome-immunoproteomic knowledge related to chronic pelvic pain, endometriosis, and co-occurring gynecologic conditions that can help improve the treatment of patients seeking care for pain.

Causal association of immune cells and endometriosis: a Mendelian randomization study

Objective

To investigate the causal effect of immune cells on endometriosis (EMS), we performed a Mendelian randomization analysis.

Methods

Mendelian randomization (MR) uses genetic variants as instrumental variables to investigate the causal effects of exposures on outcomes in observational data. In this study, we conducted a thorough two-sample MR analysis to investigate the causal relationship between 731 immune cells and endometriosis. We used complementary Mendelian randomization (MR) methods, including weighted median estimator (WME) and inverse variance weighted (IVW), and performed sensitivity analyses to assess the robustness of our results.

Results

Four immune phenotypes have been found to be significantly associated with the risk of developing EMS: B cell %lymphocyte (WME: OR: 1.074, p = 0.027 and IVW: OR: 1.058, p = 0.008), CD14 on Mo MDSC (WME: OR: 1.056, p =0.021 and IVW: OR: 1.047, p = 0.021), CD14+ CD16- monocyte %monocyte (WME: OR: 0.947, p = 0.024 and IVW: OR: 0.958, p = 0.011), CD25 on unsw mem (WME: OR: 1.055, p = 0.030 and IVW: OR: 1.048, p = 0.003). Sensitivity analyses confirmed the main findings, demonstrating consistency across analyses.

Conclusions

Our MR analysis provides compelling evidence for a direct causal link between immune cells and EMS, thereby advancing our understanding of the disease. It also provides new avenues and opportunities for the development of immunomodulatory therapeutic strategies in the future.

The Known, the Unknown and the Future of the Pathophysiology of Endometriosis

Endometriosis is one of the most common causes of chronic pelvic pain and infertility, affecting 10% of women of reproductive age. A delay of up to 9 years is estimated between the onset of symptoms and the diagnosis of endometriosis. Endometriosis is currently defined as the presence of endometrial epithelial and stromal cells at ectopic sites; however, advances in research on endometriosis have some authors believing that endometriosis should be re-defined as "a fibrotic condition in which endometrial stroma and epithelium can be identified". There are several theories on the etiology of the disease, but the origin of endometriosis remains unclear. This review addresses the role of microRNAs (miRNAs), which are naturally occurring post-transcriptional regulatory molecules, in endometriotic lesion development, the inflammatory environment within the peritoneal cavity, including the role that cytokines play during the development of the disease, and how animal models have helped in our understanding of the pathology of this enigmatic disease.

Endometriosis and endometrial cancer: A propensity score-adjusted real-world data study

Endometriosis is a benign condition characterized by the presence of ectopic endometrial tissue. Our study investigated the effect of endometriosis on the risk of endometrial cancer (EC) and the prognosis of endometriosis-associated EC. In our study, 197,196 patients with endometriosis and without a previous diagnosis of EC were compared with 6,455,556 females encountering health services for examinations, with body mass index (BMI) data, and without endometriosis or EC. A propensity score generated 197,141 matched pairs. In the endometriosis cohort, 875 cases of EC were seen, whereas 558 were in the control group: the hazard ratio (HR) was 1.56 (95% CI 1.40-1.73, p < 0.001). Women with endometriosis were more likely to develop invasive endometrioid (p = 0.005) and clear cell (p < 0.001) EC. There was no difference in overall survival between endometriosis-associated EC and EC without endometriosis. Our epidemiological findings were consistent with the evidence of an association between endometriosis and EC.

The mysterious association between adiponectin and endometriosis

Adiponectin is a pleiotropic cytokine predominantly derived from adipose tissue. In addition to its role in regulating energy metabolism, adiponectin may also be related to estrogen-dependent diseases, and many studies have confirmed its involvement in mediating diverse biological processes, including apoptosis, autophagy, inflammation, angiogenesis, and fibrosis, all of which are related to the pathogenesis of endometriosis. Although many researchers have reported low levels of adiponectin in patients with endometriosis and suggested that it may serve as a protective factor against the development of the disease. Therefore, the purpose of this review was to provide an up-to-date summary of the roles of adiponectin and its downstream cytokines and signaling pathways in the aforementioned biological processes. Further systematic studies on the molecular and cellular mechanisms of action of adiponectin may provide novel insights into the pathophysiology of endometriosis as well as potential therapeutic targets.

Spatial Transcriptomic Analysis Identifies Epithelium-Macrophage Crosstalk in Endometriotic Lesions

The mechanisms underlying the pathophysiology of endometriosis, characterized by the presence of endometrium-like tissue outside the uterus, remain poorly understood. This study aimed to identify cell type-specific gene expression changes in superficial peritoneal endometriotic lesions and elucidate the crosstalk among the stroma, epithelium, and macrophages compared to patient-matched eutopic endometrium. Surprisingly, comparison between lesions and eutopic endometrium revealed transcriptional similarities, indicating minimal alterations in the sub-epithelial stroma and epithelium of lesions. Spatial transcriptomics highlighted increased signaling between the lesion epithelium and macrophages, emphasizing the role of the epithelium in driving lesion inflammation. We propose that the superficial endometriotic lesion epithelium orchestrates inflammatory signaling and promotes a pro-repair phenotype in macrophages, providing a new role for Complement 3 in lesion pathobiology. This study underscores the significance of considering spatial context and cellular interactions in uncovering mechanisms governing disease in endometriotic lesions.

Stress, pain, anxiety, and depression in endometriosis-Targeting glial activation and inflammation

Endometriosis (EM) is a gynecological inflammatory disease often accompanied by stress, chronic pelvic pain (CPP), anxiety, and depression, leading to a diminished quality of life. This review aims to discuss the relationship between systemic and local inflammatory responses in the central nervous system (CNS), focusing on glial dysfunctions (astrocytes and microglia) as in critical brain regions involved in emotion, cognition, pain processing, anxiety, and depression. The review presents that EM is connected to increased levels of pro-inflammatory cytokines in the circulation. Additionally, chronic stress and CPP as stressors may contribute to the dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, depleting the production of inflammatory mediators in the circulatory system and the brain. The systemic cytokines cause blood-brain barrier (BBB) breakdown, activate microglia in the brain, and lead to neuroinflammation. Furthermore, CPP may induce neuronal morphological alterations in critical regions through central sensitization and the activation of glial cells. The activation of glial cells, particularly the polarization of microglia, leads to the activation of the NLRP3 inflammasome and the overproduction of inflammatory cytokines. These inflammatory cytokines interact with the signaling pathways involved in neural plasticity. Additionally, persistent inflammatory conditions in the brain lead to neuronal death, which is correlated with a reduced volume of key brain regions such as the hippocampus. This review highlights the involvement of glial cells in the pathogenesis of the mental comorbidities of EM (i.e., pain, anxiety, and depression) and to discuss potential therapeutic approaches for targeting the inflammation and activation of microglia in key brain regions.

The pathogenesis of endometriosis and adenomyosis: insights from single-cell RNA sequencing†

Endometriosis and adenomyosis are two similar gynecological diseases that are characterized by ectopic implantation and the growth of the endometrial tissue. Previous studies have reported that they share a common pathophysiology in some respects, such as a similar cellular composition and resistance to the progestogen of lesions, but their underlying mechanisms remain elusive. Emerging single-cell ribonucleic acid sequencing (scRNA-seq) technologies allow for the dissection of single-cell transcriptome mapping to reveal the etiology of diseases at the level of the individual cell. In this review, we summarized the published findings in research on scRNA-seq regarding the cellular components and molecular profiles of diverse lesions. They show that epithelial cell clusters may be the vital progenitors of endometriosis and adenomyosis. Subclusters of stromal cells, such as endometrial mesenchymal stem cells and fibroblasts, are also involved in the occurrence of endometriosis and adenomyosis, respectively. Moreover, CD8+ T cells, natural killer cells, and macrophages exhibit a deficiency in clearing the ectopic endometrial cells in the immune microenvironment of endometriosis. It seems that the immune responses are activated in adenomyosis. Understanding the immune characteristics of adenomyosis still needs further exploration. Finally, we discuss the application of findings from scRNA-seq for clinical diagnosis and treatment. This review provides fresh insights into the pathogenesis of endometriosis and adenomyosis as well as the therapeutic targets at the cellular level.

Transcriptomic changes in eutopic endometrium and ectopic lesions during endometriosis progression in a mouse model

OBJECTIVE

To identify the transcriptomic changes of ectopic lesions and eutopic endometrial tissues during the progression of endometriosis, we performed transcriptomic analysis in the eutopic endometrium and ectopic lesions.

DESIGN

Laboratory study.

SETTING

Academic medical center.

ANIMALS

Four fertile and 4 subfertile Pgrcre/+Rosa26mTmG/+ mice with endometriosis, and 4 sham mice for each group of endometriosis mice as control. These mice underwent either surgery to induce endometriosis or sham surgery. Fertile sham and mice with endometriosis were used 1 month after surgery, whereas subfertile ones were used 3 months after surgery.

INTERVENTIONS

Early and chronic effects of endometriosis on transcriptomics of ectopic lesions and eutopic endometrium.

MAIN OUTCOME MEASURES

RNA-sequencing analysis and identification of differentially expressed genes and pathways in the ectopic lesions and eutopic uteri from mice with endometriosis and sham mice at day 3.5 of pregnancy.

RESULTS

Our mouse model recapitulates the transcriptomic changes of ectopic lesions in humans. RNA-sequencing analysis was performed in ectopic lesions and eutopic uteri from mice with or without endometriosis during the progression of the disease. Estrogen activity, inflammation, angiogenesis, and fibrosis pathways were consistently elevated in all the ectopic lesions compared with eutopic endometrium. Cholesterol/glucose synthesis and stem cell pluripotency pathways were more enhanced in ectopic lesions from subfertile mice compared with their eutopic endometrium. Dysregulation of infiltration of macrophage, dendritic, T and B cells was validated with the use of immunohistochemistry in ectopic lesions. Multiple ligand-receptor pairs between the ectopic and eutopic endometrium were altered compared with the sham endometrium. Suppressed WNT and EGF pathways were only found in the eutopic endometrium from subfertile not fertile mice compared with sham.

CONCLUSIONS

Our mouse endometriosis model recapitulates the transcriptomics of ectopic lesions in humans. Our transcriptomic analysis during endometriosis progression in our mouse model will help us understand the pathophysiology of endometriosis.

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.

Extracellular vesicles in endometriosis: role and potential

Endometriosis is a chronic inflammatory gynecological disease, which profoundly jeopardizes women's quality of life and places a significant medical burden on society. The pathogenesis of endometriosis remains unclear, posing major clinical challenges in diagnosis and treatment. There is an urgent demand for the development of innovative non-invasive diagnostic techniques and the identification of therapeutic targets. Extracellular vesicles, recognized for transporting a diverse array of signaling molecules, have garnered extensive attention as a novel mode of intercellular communication. A burgeoning body of research indicates that extracellular vesicles play a pivotal role in the pathogenesis of endometriosis, which may provide possibility and prospect for both diagnosis and treatment. In light of this context, this article focuses on the involvement of extracellular vesicles in the pathogenesis of endometriosis, which deliver information among endometrial stromal cells, macrophages, mesenchymal stem cells, and other cells, and explores their potential applications in the diagnosis and treatment, conducing to the emergence of new strategies for clinical diagnosis and treatment.

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.

Altered Glycolysis, Mitochondrial Biogenesis, Autophagy and Apoptosis in Peritoneal Endometriosis in Adolescents

Energy metabolism plays a pivotal role in the pathogenesis of endometriosis. For the initial stages of the disease in adolescents, this aspect remains unexplored. The objective of this paper was to analyze the association of cellular and endosomal profiles of markers of glycolysis, mitochondrial biogenesis, apoptosis, autophagy and estrogen signaling in peritoneal endometriosis (PE) in adolescents. We included 60 girls aged 13-17 years in a case-control study: 45 with laparoscopically confirmed PE (main group) and 15 with paramesonephric cysts (comparison group). Samples of plasma and peritoneal fluid exosomes, endometrioid foci and non-affected peritoneum were tested for estrogen receptor (Erα/β), hexokinase (Hex2), pyruvate dehydrogenase kinase (PDK1), glucose transporter (Glut1), monocarboxylate transporters (MCT1 and MCT2), optic atrophy 1 (OPA1, mitochondrial fusion protein), dynamin-related protein 1 (DRP1, mitochondrial fission protein), Bax, Bcl2, Beclin1, Bnip3, P38 mitogen-activated protein kinase (MAPK), hypoxia-inducible factor 1 (Hif-1α), mitochondrial voltage-dependent anion channel (VDAC) and transforming growth factor (TGFβ) proteins as markers of estrogen signaling, glycolysis rates, mitochondrial biogenesis and damage, apoptosis and autophagy (Western-Blot and PCR). The analysis identified higher levels of molecules associated with proliferation (ERβ), glycolysis (MCT2, PDK1, Glut1, Hex2, TGFβ and Hif-1α), mitochondrial biogenesis (OPA1, DRP1) and autophagy (P38, Beclin1 and Bnip3) and decreased levels of apoptosis markers (Bcl2/Bax) in endometrioid foci compared to non-affected peritoneum and that in the comparison group (p < 0.05). Patients with PE had altered profiles of ERβ in plasma and peritoneal fluid exosomes and higher levels of Glut1, MCT2 and Bnip3 in plasma exosomes (p < 0.05). The results of the differential expression profiles indicate microenvironment modification, mitochondrial biogenesis, estrogen reception activation and glycolytic switch along with apoptosis suppression in peritoneal endometrioid foci already in adolescents.

Horizons in Endometriosis: Proceedings of the Montreux Reproductive Summit, 14-15 July 2023

Endometriosis is a complex and chronic gynaecological disorder that affects millions of women worldwide, leading to significant morbidity and impacting reproductive health. This condition affects up to 10% of women of reproductive age and is characterised by the presence of endometrial-like tissue outside the uterus, potentially leading to symptoms such as chronic pelvic pain, dysmenorrhoea, dyspareunia, and infertility. The Montreux summit brought a number of experts in this field together to provide a platform for discussion and exchange of ideas. These proceedings summarise the six main topics that were discussed at this summit to shed light on future directions of endometriosis classification, diagnosis, and therapeutical management. The first question addressed the possibility of preventing endometriosis in the future by identifying risk factors, genetic predispositions, and further understanding of the pathophysiology of the condition to develop targeted interventions. The clinical presentation of endometriosis is varied, and the correlation between symptoms severity and disease extent is unclear. While there is currently no universally accepted optimal classification system for endometriosis, several attempts striving towards its optimisation - each with its own advantages and limitations - were discussed. The ideal classification should be able to reconcile disease status based on the various diagnostic tools, and prognosis to guide proper patient tailored management. Regarding diagnosis, we focused on future tools and critically discussed emerging approaches aimed at reducing diagnostic delay. Preserving fertility in endometriosis patients was another debatable aspect of management that was reviewed. Moreover, besides current treatment modalities, potential novel medical therapies that can target underlying mechanisms, provide effective symptom relief, and minimise side effects in endometriotic patients were considered, including hormonal therapies, immunomodulation, and regenerative medicine. Finally, the question of hormonal substitution therapy after radical treatment for endometriosis was debated, weighing the benefits of hormone replacement.

Soluble Factors CD14, CD163, and Migration Inhibitory Factor Are Associated with Endometriosis-Related Infertility

OBJECTIVES

Myeloid cell-derived factors contribute to the immunopathology of endometriosis. Soluble CD14 (sCD14), CD163 (sCD163), and MIF serve as in vivo markers of myeloid function. However, these soluble molecules are largely unexplored in women with endometriosis-related infertility cases. We investigated three soluble markers, namely sCD14, sCD163, and MIF, in cases of infertility associated with endometriosis and correlated its level to the stage of endometriosis.

DESIGN

Eighty-seven women newly diagnosed with endometriosis or other benign gynecologic control cases linked to infertility were prospectively recruited and underwent diagnostic laparoscopy.

PARTICIPANTS

Forty-four patients with endometriosis were included in this study, comprising 19 patients with early-endometriosis (stages I and II) and 25 late-endometriosis (stages III and IV) based on the revised American Society for Reproductive Medicine (rASRM) classification. The remaining 43 patients constituted a control group with infertility due to other causes.

METHODS

The levels of sCD14, sCD163, and MIF in serum and peritoneal fluid were assessed using ELISA.

RESULTS

Endometriosis women exhibited significantly higher serum levels of sCD163 and MIF levels compared to the control group. Both sCD163 and MIF levels displayed a positive correlation with the rASRM adhesion score. Moreover, the MIF level in serum had a positive correlation with the rASRM endometriosis score. In receiver operating characteristic analysis, serum sCD163 and MIF could significantly discriminate endometriosis and non-endometriosis in infertility cases.

LIMITATIONS

Some limitations of the current study deserve to be underlined. First, the sensitive ELISA method was the sole-validated tool for detecting the markers in patient samples. Second, healthy or fertile women were not involved as the control group.

CONCLUSIONS

The elevated systemic levels of sCD163 and MIF correlated with the severity of endometriosis. These soluble molecules have a potential diagnostic capacity as a non-invasive biomarker. Furthermore, our data warrants future studies on the underlying mechanism of sCD163 and MIF in endometriosis-related infertility.

Macrophage polarization in adenomyosis: A review

Adenomyosis (AM) is a common gynecological disorder characterized by the presence of endometrial glands and stroma within the uterine myometrium. It is associated with abnormal uterine bleeding (AUB), dysmenorrhea, and infertility. Although several mechanisms have been proposed to elucidate AM, the exact cause and development of the condition remain unclear. Recent studies have highlighted the significance of macrophage polarization in the microenvironment, which plays a crucial role in AM initiation and progression. However, a comprehensive review regarding the role and regulatory mechanism of macrophage polarization in AM is currently lacking. Therefore, this review aims to summarize the phenotype and function of macrophage polarization and the phenomenon of the polarization of adenomyosis-associated macrophages (AAMs). It also elaborates on the role and regulatory mechanism of AAM polarization in invasion/migration, fibrosis, angiogenesis, dysmenorrhea, and infertility. Furthermore, this review explores the underlying molecular mechanisms of AAM polarization and suggests future research directions. In conclusion, this review provides a new perspective on understanding the pathogenesis of AM and provides a theoretical foundation for developing targeted drugs through the regulation of AAM polarization.

High-fat diets promote peritoneal inflammation and augment endometriosis-associated abdominal hyperalgesia

Immune dysfunction is one of the central components in the development and progression of endometriosis by establishing a chronic inflammatory environment. Western-style high-fat diets (HFD) have been linked to greater systemic inflammation to cause metabolic and chronic inflammatory diseases, and are also considered an environmental risk factor for gynecologic diseases. Here, we aimed to examine how HFD cause an inflammatory environment in endometriosis and discern their contribution to endometriotic-associated hyperalgesia. Our results showed that HFD-induced obesity enhanced abdominal hyperalgesia that was induced by endometriotic lesions. Peritoneal inflammatory macrophages and cytokine levels increased by lesion induction were elevated by chronic exposure to HFD. Increased expression of pain-related mediators in the dorsal root ganglia was observed after lesion induction under the HFD condition. Although HFD did not affect inflammatory macrophages in the peritoneal cavity without lesion induction, the diversity and composition of the gut microbiota were clearly altered by HFD as a sign of low-grade systemic inflammation. Thus, HFD alone might not establish a local inflammatory environment in the pelvic cavity, but it can contribute to further enhancing chronic inflammation, leading to the exacerbation of endometriosis-associated abdominal hyperalgesia following the establishment and progression of the disease.