The endometrial immune environment of women with endometriosis

Effects of various controlled ovarian hyperstimulation protocols and surgery on pregnancy outcomes in women with endometriosis

Endometriosis is a common gynecological condition in women of childbearing age that causes symptoms such as menstrual changes and dysmenorrhea, and is also a major cause of infertility. Therefore, women with endometriosis usually need to use assisted reproductive technology (ART), such as in vitro fertilization or intracytoplasmic sperm injection, to increase their chances of conceiving. Numerous clinical observations and studies have indicated that endometriosis can affect the success of ART, such that women with endometriosis who use ART have a lower live-birth rate than those without endometriosis who use ART. Therefore, this article reviews the impact of various controlled ovarian hyperstimulation protocols and surgery on the pregnancy outcomes of women with endometriosis using ART to explore the selection of individualized treatment.

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.

Hypoxia-induced Semaphorin 3A promotes the development of endometriosis through regulating macrophage polarization

BACKGROUND

Semaphorin 3A (Sema3A) is a member of neural guidance factor family well-known for inducing the collapse of nerve cell growth cone and regulating nerve redistribution. It also has been characterized as an immunoregulatory and tumor promoting factor. Our previous study showed that Sema3A was involved in the regulation of sympathetic innervation and neuropathic pain of endometriosis. Nevertheless, the role of Sema3A in the development of endometriosis and its potential upstreaming factor are still not clear.

METHODS

Histology experiments were carried to detect the expression of Sema3A, hypoxia -inducible factor 1α (HIF-1α) and the distribution of macrophages. Cell experiments were used to explore the effect of Sema3A on the proliferation and migration of endometrial stromal cells (ESCs) and to confirm the regulatory action of HIF-1α on Sema3A. In vivo experiments were carried out to explore the role of Sema3A on the development of endometriosis.

RESULTS

Sema3A was highly expressed in endometriotic lesions and could enhanced the proliferation and migration abilities of ESCs. Aberrant macrophage distribution was found in endometriotic lesions. Sema3A also promoted the differentiation of monocytes into anti-inflammatory macrophages, so indirectly mediating the proliferation and migration of ESCs. Hypoxic microenvironment induced Sema3A mRNA and protein expression in ESCs via HIF-1α. Administration of Sema3A promoted the development of endometriosis in a mouse model.

CONCLUSIONS

Sema3A, which is regulated by HIF-1α, is a promoting factor for the development of endometriosis. Targeting Sema3A may be a potential treatment strategy to control endometriotic lesions.

Integrin β3 enhances glycolysis and increases lactate production in endometriosis

BACKGROUND

Endometriosis (EMs) is a chronic disease characterized by endometrial-like tissue present outside of the uterus. Macrophages have been confirmed to participate in the development of EMs. Integrin β3 (ITGB3), a β-subunit of the integrin family, is crucial in tumor progression. In this study, we investigated the pivotal role of ITGB3 in endometrial stromal cells (ESCs) and its influence on the development of EMs, particularly focusing on the regulatory impact of macrophages.

METHODS

In this study, we used western blot, Real-time qPCR, Immunohistochemistry to detected the high expression of ITGB3 in ESCs. ITGB3-overexpression ESCs (ITGB3-OE) was constructed and detected by RNA-seq with normal ESCs. ATP and lactate expression assay, transwell migration assay, wound healing, cell adhesion assay and other molecular biology techniques were used to explore the potential mechanisms. In vivo, we constructed the EMs mouse model and injected with cilengitite to inhibit ITGB3.

RESULTS

Here, we found ITGB3 highly expressed in ectopic lesions in EMs. The increasing ITGB3 resulted in activating the glycolysis, which produced more ATP and lactate in ITGB3-OE. After culturing with lactate, the migration, proliferation and invasion ability of ESCs were enhanced, while the result in 2-DG was reversed. In vivo, the results showed that after antagonizing ITGB3, the number of ectopic lesions was decrease.

CONCLUSIONS

Our findings indicate that ITGB3 up-regulated by macrophages are able to regulate the glycolysis to promote the development of EMs and lactate enhances the ability of proliferation, migration, invasion and adhesion of EMs iv vivo and in vitro.

Regional Analysis of the Immune Microenvironment in Human Endometrium

PROBLEM

Endometrial immune cells are essential for maintaining homeostasis and the endometrial receptivity to embryo implantation. Understanding regional variations in endometrial immune cell populations is crucial for comprehending normal endometrial function and the pathophysiology of endometrial disorders. Despite previous studies focusing on the overall immune cell composition and function in the endometrium, regional variations in premenopausal women remain unclear.

METHOD OF STUDY

Endometrial biopsies were obtained from four regions (anterior, posterior, left lateral, and right lateral) of premenopausal women undergoing hysteroscopy with no abnormalities. A 15-color human endometrial immune cell-focused flow cytometry panel was used for analysis. High-dimensional flow cytometry combined with a clustering algorithm was employed to unravel the complexity of endometrial immune cells. Additionally, multiplex immunofluorescent was performed for further validation.

RESULTS

Our findings revealed no significant variation in the distribution and abundance of immune cells across different regions under normal conditions during the proliferative phase. Each region harbored similar immune cell subtypes, indicating a consistent immune microenvironment. However, when comparing normal regions to areas with focal hemorrhage, significant differences were observed. An increase in CD8+ T cells highlights the impact of localized abnormalities on the immune microenvironment.

CONCLUSIONS

Our study demonstrates that the endometrial immune cell landscape is consistent across different anatomical regions during the proliferative phase in premenopausal women. This finding has important implications for understanding normal endometrial function and the pathophysiology of endometrial disorders.

An integrated single-cell reference atlas of the human endometrium

The complex and dynamic cellular composition of the human endometrium remains poorly understood. Previous endometrial single-cell atlases profiled few donors and lacked consensus in defining cell types. We introduce the Human Endometrial Cell Atlas (HECA), a high-resolution single-cell reference atlas (313,527 cells) combining published and new endometrial single-cell transcriptomics datasets of 63 women with and without endometriosis. HECA assigns consensus and identifies previously unreported cell types, mapped in situ using spatial transcriptomics and validated using a new independent single-nuclei dataset (312,246 nuclei, 63 donors). In the functionalis, we identify intricate stromal-epithelial cell coordination via transforming growth factor beta (TGFβ) signaling. In the basalis, we define signaling between fibroblasts and an epithelial population expressing progenitor markers. Integration of HECA with large-scale endometriosis genome-wide association study data pinpoints decidualized stromal cells and macrophages as most likely dysregulated in endometriosis. The HECA is a valuable resource for studying endometrial physiology and disorders, and for guiding microphysiological in vitro systems development.

Ultrasound study of natural progression of ovarian endometrioma

OBJECTIVE

To determine the natural progression of ovarian endometrioma in women who are managed expectantly.

METHODS

This was a retrospective cohort study of 83 women with evidence of ovarian endometrioma who were managed expectantly between April 2007 and May 2022. The study was conducted in the Department of Women's Health, University College London Hospitals and The Gynecology Ultrasound Centre, London, UK. We searched our ultrasound clinic databases to identify women aged 18 years or older with evidence of ovarian endometrioma who were managed expectantly for ≥ 6 months. All women attended for a minimum of two ultrasound scans performed by a single expert ultrasound operator. In addition to patient demographics, we recorded the number, mean diameter and location of each cyst. The cyst growth rate was expressed as annual change in the mean diameter.

RESULTS

A total of 1922 women who attended our gynecology clinic during the study period were found to have evidence of moderate or severe endometriosis on pelvic ultrasound examination. Of those, 83 women had evidence of ovarian endometrioma and were managed expectantly. The median age of women was 39 (range, 26-51) years at the initial visit. Each woman had at least two ultrasound scans performed by a single expert operator at a minimum interval of ≥ 6 months. Of 83 women diagnosed with endometrioma, 50 (60% (95% CI, 49-71%)) had a single cyst and the remainder had multiple cysts. The median number of endometriomas per patient was 1 (range, 1-5) and the median follow-up time was 634 (range, 187-2984) days. A total of 39/83 (47% (95% CI, 36-58%)) women experienced an overall reduction in size of cysts, in 18/83 (22% (95% CI, 13-32%)) the cysts increased in size and in 26/83 (31% (95% CI, 22-42%)) women, no meaningful change in size was observed. The median change in mean cyst diameter per woman during the study period was -2.7 (range, -57.7 to 39.3) mm, with a median annual regression rate of -1.7 (range, -24.6 to 42.0) mm/year/woman. Overall, when compared with the initial visit, cysts were significantly smaller at follow-up (median diameter, 22.3 (range, 6.7-77.0) mm vs 18.5 (range, 5.0-72.0) mm; P = 0.009). We did not identify any clinical characteristics that could reliably predict the chance of endometrioma progression.

CONCLUSIONS

In the majority of women with an ultrasound diagnosis of ovarian endometrioma, the cysts do not increase in size significantly over time and they could be managed expectantly. This evidence may help clinicians when counseling asymptomatic or minimally symptomatic women about management of ovarian endometrioma. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Expression patterns of HDAC6 in correlation to ARID1A status in different subtypes of endometriosis: A retrospective tissue microarray analysis

Endometriosis is a disease affecting approximately 10% of reproductive age women. Loss of the tumor suppressor gene AT-rich interactive domain-containing protein 1A (ARID1A) occurs in some endometriosis cases. Histone deacetylase 6 (HDAC-6) is an enzyme with implication in several diseases including different cancer types and immunological disorders, where it is involved in protein trafficking and degradation, cell shape, and migration. In ARID1A-deficient ovarian cancer increased HDAC-6 expression lead to apoptosis-inhibiting post-translational modification of p53. It is not known if HDAC-6 expression is also altered in ARID1A-deficient endometriosis. The aim of this study was to assess HDAC-6 expression in endometriotic lesions in correlation to ARID1A-status. Two tissue-microarrays with 168 endometriotic lesions, including ovarian (64/168, 38 %), peritoneal (66/168, 39 %) and deep-infiltrating (38/168, 23 %) subtypes, and 73 endometrium of women without endometriosis were assessed. Mean ARID1A immunoreactivity score (IRS) in endometriosis group was 10.83 (±2.36) and 10.78 (±1.94) in the epithelium and stroma, respectively, while the respective mean HDAC6 IRS were 9.16 (±2.76) and 5.94 (±2.88). The comparison of the HDAC6 expression between endometriosis subtypes showed higher expression in deep-infiltrating endometriosis, in both, epithelium (p = 0.032) and stroma (p = 0.007). In ARID1A negative cases, epithelial expression of HDAC6 was higher in endometriosis compared to women without endometriosis (p = 0.031), and this was also specifically observed in the subset of ovarian endometriosis (p = 0.037). There were no significant differences in the stromal expression of HDAC6. In conclusion, our results demonstrate a complex expression pattern of HDAC6 depending on ARID1A status in different endometriosis subtypes. Further studies on HDAC6 and ARID1A are important to elucidate mechanisms involved in malignant transformation of endometriosis.

Management of patients with endometriosis and infertility: laparoscopic treatment and spontaneous pregnancy rate

OBJECTIVE

To evaluate factors involved in spontaneous pregnancy rate after surgery for endometriosis in patients with endometriosis and infertility.

METHODS

This retrospective study spanned from 2014 to 2020 and included a follow-up period of two years of patients with endometriosis-related infertility who underwent laparoscopic surgery. Women aged 25 to 43 years with patent tubes, no/mild male factor and no other infertility factors were selected and grouped according to fertility management as follows: patients immediately prescribed ART (16.5%, ART-p); patients who chose not to undergo ART (83.5%) and achieved spontaneous pregnancy (71.8% SP-p); and patients who first chose not to undergo ART but had it subsequently (28.2%, NSP-p).

RESULTS

A total of 200 patients were analyzed. Of the 167 patients who waited for spontaneous pregnancy, 71.8% achieved it. We observed a tendency of higher endometriosis ASRM scores in the ART-p group compared with patients who waited for spontaneous pregnancy, and lower scores in individuals that achieved spontaneous pregnancy. When we looked at how long it took to achieve pregnancy, we found that individuals in the SP-p group achieved pregnancy in 5.7 months, while subjects in the NSP-p group took 1.8 times longer than their peers in the SP-p group (p<0.001). However, once prescribed ART, the individuals in the NSP-p group achieved pregnancy within a similar time when compared with subjects in the SP-p group. In order to identify individuals that might benefit from ART early on, we performed a multivariable analysis and developed a decision tree (81.3% accuracy and 53.3% sensitivity).

CONCLUSIONS

The present results indicated that, after surgery, the majority of patients achieved spontaneous pregnancy. The decision tree proposed in this study allows the early identification of patients who might require ART, thus decreasing the time between surgery and pregnancy and improving overall outcomes.

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.

Quercetin enhances decidualization through AKT-ERK-p53 signaling and supports a role for senescence in endometriosis

BACKGROUND

Patients with endometriosis suffer with chronic pelvic pain and infertility, and from the lack of pharmacologic therapies that consistently halt disease progression. Differences in the endometrium of patients with endometriosis vs. unaffected controls are well-documented. Specifically, shed endometrial tissues (delivered to the pelvic cavity via retrograde menstruation) reveal that a subset of stromal cells exhibiting pro-inflammatory, pro-fibrotic, and pro-senescence-like phenotypes is enhanced in endometriosis patients compared to controls. Additionally, cultured biopsy-derived endometrial stromal cells from endometriosis patients exhibit impaired decidualization, a defined differentiation process required for human embryo implantation and pregnancy. Quercetin, a senolytic agent, shows therapeutic potential for pulmonary fibrosis, a disorder attributed to senescent pulmonary fibroblasts. In rodent models of endometriosis, quercetin shows promise, and quercetin improves decidualization in vitro. However, the exact mechanisms are not completely understood. Therefore, we investigated the effects of quercetin on menstrual effluent-derived endometrial stromal cells from endometriosis patients and unaffected controls to define the signaling pathways underlying quercetin's effects on endometrial stromal cells.

METHODS

Menstrual effluent-derived endometrial stromal cells were collected and cultured from unaffected controls and endometriosis patients and then, low passage cells were treated with quercetin (25 µM) under basal or standard decidualization conditions. Decidualization responses were analyzed by measuring the production of IGFBP1 and PRL. Also, the effects of quercetin on intracellular cAMP levels and cellular oxidative stress responses were measured. Phosphokinase arrays, western blotting, and flow cytometry methods were performed to define the effects of quercetin on various signaling pathways and the potential mechanistic roles of quercetin.

RESULTS

Quercetin significantly promotes decidualization of control- and endometriosis-endometrial stromal cells. Quercetin substantially reduces the phosphorylation of multiple signaling molecules in the AKT and ERK1/2 pathways, while enhancing the phosphorylation of p53 and total p53 levels. Furthermore, p53 inhibition blocks decidualization while p53 activation promotes decidualization. Finally, we provide evidence that quercetin increases apoptosis of endometrial stromal cells with a senescent-like phenotype.

CONCLUSIONS

These data provide insight into the mechanisms of action of quercetin on endometrial stromal cells and warrant future clinical trials to test quercetin and other senolytics for treating endometriosis.

CCL18 promotes endometriosis by increasing endometrial cell migration and neuroangiogenesis

Endometriosis is an estrogen-dependent inflammatory gynecological disease whose pathogenesis is unclear. C-C motif chemokine ligand 18 (CCL18), a chemokine, is involved in several inflammatory diseases. In this study, we aimed to investigate the role of CCL18 in endometriosis and its underlying mechanisms. Human endometrium and peritoneal fluid were obtained from women with and without endometriosis for molecular studies. The expression level of CCL18 in each tissue sample was examined by RNA sequencing analysis, quantitative PCR analysis and immunohistochemistry staining. The effects of CCL18 on cell migration, tube formation and neurite growth were investigated in vitro using primary endometrial cells, human umbilical vein endothelial cells (HUVECs) and dorsal root ganglion (DRG) neurons, respectively. Moreover, the development of endometriosis in mice was studied in vivo by blocking CCL18. CCL18 was shown to be overexpressed in endometrial foci and peritoneal fluid in women with endometriosis and was positively correlated with endometriosis pain. In vitro, CCL18 promoted the migration of ectopic endometrial cells, tube formation of HUVECs, and nerve outgrowth of DRG neurons. More importantly, inhibition of CCL18 significantly suppressed lesion development, angiogenesis, and nerve infiltration in a mouse model of endometriosis. In conclusion, CCL18 may play a role in the progression of endometriosis by increasing endometrial cell migration and promoting neuroangiogenesis.

Amphiregulin secreted by umbilical cord multipotent stromal cells protects against ferroptosis of macrophages via the activating transcription factor 3-CD36 axis to alleviate endometrial fibrosis

Endometrium fibrosis is the leading cause of uterine infertility. Macrophages participated in the occurrence and development of endometrial fibrosis. We previously reported that human umbilical cord multipotent stromal cells (hUC-MSCs) exerted their therapeutic effect in a macrophage-dependent manner in endometrial fibrosis. However precise mechanisms by which hUC-MSCs may influence macrophages in endometrial fibrosis remain largely unexplored. Here, we demonstrated that abnormal iron and lipid metabolism occurred in patients with intrauterine adhesions (IUA) and murine models. Ferroptosis has been proven to contribute to the progression of fibrotic diseases. Our results revealed that pharmacological activation of ferroptosis by Erastin aggravated endometrial fibrosis, while inhibition of ferroptosis by Ferrostatin-1 ameliorated endometrial fibrosis in vivo. Moreover, ferroptosis of macrophages was significantly upregulated in endometria of IUA murine models. Of note, transcriptome profiles revealed that CD36 gene expression was significantly increased in patients with IUA and immunofluorescence analysis showed CD36 protein was mainly located in macrophages. Silencing CD36 in macrophages could reverse cell ferroptosis. Dual luciferase reporter assay revealed that CD36 was the direct target of activation transcription factor 3 (ATF3). Furthermore, through establishing coculture system and IUA murine models, we found that hUC-MSCs had a protective role against macrophage ferroptosis and alleviated endometrial fibrosis related to decreased CD36 and ATF3. The effect of hUC-MSCs on macrophage ferroptosis was attributed to the upregulation of amphiregulin (AREG). Our data highlighted that macrophage ferroptosis occurred in endometrial fibrosis via the ATF3-CD36 pathway and hUC-MSCs protected against macrophage ferroptosis to alleviate endometrial fibrosis via secreting AREG. These findings provided a potential target for therapeutic implications of endometrial fibrosis.

Identification and Immune Characteristics Study of Pyroptosis‑Related Genes in Endometriosis

Endometriosis (EMT) is a prevalent gynecological disorder characterized by pain and infertility associated with the menstrual cycle. Pyroptosis, an emerging cell death mechanism, has been implicated in the pathogenesis of diverse diseases, highlighting its pivotal role in disease progression. Therefore, our study aimed to investigate the impact of pyroptosis in EMT using a comprehensive bioinformatics approach. We initially obtained two datasets from the Gene Expression Omnibus database and performed differential expression analysis to identify pyroptosis-related genes (PRGs) that were differentially expressed between EMT and non-EMT samples. Subsequently, several machine learning algorithms, namely least absolute shrinkage selection operator regression, support vector machine-recursive feature elimination, and random forest algorithms were used to identify a hub gene to construct an effective diagnostic model for EMT. Receiver operating characteristic curve analysis, nomogram, calibration curve, and decision curve analysis were applied to validate the performance of the model. Based on the selected hub gene, differential expression analysis between high- and low-expression groups was conducted to explore the functions and signaling pathways related to it. Additionally, the correlation between the hub gene and immune cells was investigated to gain insights into the immune microenvironment of EMT. Finally, a pyroptosis-related competing endogenous RNA network was constructed to elucidate the regulatory interactions of the hub gene. Our study revealed the potential contribution of a specific PRG to the pathogenesis of EMT, providing a novel perspective for clinical diagnosis and treatment of EMT.

PARP-1, EpCAM, and FRα as potential targets for intraoperative detection and delineation of endometriosis: a quantitative tissue expression analysis

BACKGROUND

Endometriosis is a gynecological disease characterized by the presence of endometrial tissue in abnormal locations, leading to severe symptoms, inflammation, pain, organ dysfunction, and infertility. Surgical removal of endometriosis lesions is crucial for improving pain and fertility outcomes, with the goal of complete lesion removal. This study aimed to analyze the location and expression patterns of poly (ADP-ribose) polymerase 1 (PARP-1), epithelial cell adhesion molecule (EpCAM), and folate receptor alpha (FRα) in endometriosis lesions and evaluate their potential for targeted imaging.

METHODS

Gene expression analysis was performed using the Turku endometriosis database (EndometDB). By immunohistochemistry, we investigated the presence and distribution of PARP-1, EpCAM, and FRα in endometriosis foci and adjacent tissue. We also applied an ad hoc platform for the analysis of images to perform a quantitative immunolocalization analysis. Double immunofluorescence analysis was carried out for PARP-1 and EpCAM, as well as for PARP-1 and FRα, to explore the expression of these combined markers within endometriosis foci and their potential simultaneous utilization in surgical treatment.

RESULTS

Gene expression analysis revealed that PARP-1, EpCAM, and FOLR1 (FRα gene) are more highly expressed in endometriotic lesions than in the peritoneum, which served as the control tissue. The results of the immunohistochemical study revealed a significant increase in the expression levels of all three biomarkers inside the endometriosis foci compared to the adjacent tissues. Additionally, the double immunofluorescence analysis consistently demonstrated the presence of PARP-1 in the nucleus and the expression of EpCAM and FRα in the cell membrane and cytoplasm.

CONCLUSION

Overall, these three markers demonstrate significant potential for effective imaging of endometriosis. In particular, the results emphasize the importance of PARP-1 expression as a possible indicator for distinguishing endometriotic lesions from adjacent tissue. PARP-1, as a potential biomarker for endometriosis, offers promising avenues for further investigation in terms of both pathophysiology and diagnostic-therapeutic approaches.

The role of fibrosis in endometriosis: a systematic review

BACKGROUND

Fibrosis is an important pathological feature of endometriotic lesions of all subtypes. Fibrosis is present in and around endometriotic lesions, and a central role in its development is played by myofibroblasts, which are cells derived mainly after epithelial-to-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transdifferentiation (FMT). Transforming growth factor-β (TGF-β) has a key role in this myofibroblastic differentiation. Myofibroblasts deposit extracellular matrix (ECM) and have contracting abilities, leading to a stiff micro-environment. These aspects are hypothesized to be involved in the origin of endometriosis-associated pain. Additionally, similarities between endometriosis-related fibrosis and other fibrotic diseases, such as systemic sclerosis or lung fibrosis, indicate that targeting fibrosis could be a potential therapeutic strategy for non-hormonal therapy for endometriosis.

OBJECTIVE AND RATIONALE

This review aims to summarize the current knowledge and to highlight the knowledge gaps about the role of fibrosis in endometriosis. A comprehensive literature overview about the role of fibrosis in endometriosis can improve the efficiency of fibrosis-oriented research in endometriosis.

SEARCH METHODS

A systematic literature search was performed in three biomedical databases using search terms for 'endometriosis', 'fibrosis', 'myofibroblasts', 'collagen', and 'α-smooth muscle actin'. Original studies were included if they reported about fibrosis and endometriosis. Both preclinical in vitro and animal studies, as well as research concerning human subjects were included.

OUTCOMES

Our search yielded 3441 results, of which 142 studies were included in this review. Most studies scored a high to moderate risk of bias according to the bias assessment tools. The studies were divided in three categories: human observational studies, experimental studies with human-derived material, and animal studies. The observational studies showed details about the histologic appearance of fibrosis in endometriosis and the co-occurrence of nerves and immune cells in lesions. The in vitro studies identified several pro-fibrotic pathways in relation to endometriosis. The animal studies mainly assessed the effect of potential therapeutic strategies to halt or regress fibrosis, for example targeting platelets or mast cells.

WIDER IMPLICATIONS

This review shows the central role of fibrosis and its main cellular driver, the myofibroblast, in endometriosis. Platelets and TGF-β have a pivotal role in pro-fibrotic signaling. The presence of nerves and neuropeptides is closely associated with fibrosis in endometriotic lesions, and is likely a cause of endometriosis-associated pain. The process of fibrotic development after EMT and FMT shares characteristics with other fibrotic diseases, so exploring similarities in endometriosis with known processes in diseases like systemic sclerosis, idiopathic pulmonary fibrosis or liver cirrhosis is relevant and a promising direction to explore new treatment strategies. The close relationship with nerves appears rather unique for endometriosis-related fibrosis and is not observed in other fibrotic diseases.

REGISTRATION NUMBER

N/A.

Unraveling pathogenesis, biomarkers and potential therapeutic agents for endometriosis associated with disulfidptosis based on bioinformatics analysis, machine learning and experiment validation

BACKGROUND

Endometriosis (EMs) is an enigmatic disease of yet-unknown pathogenesis. Disulfidptosis, a novel identified form of programmed cell death resulting from disulfide stress, stands a chance of treating diverse ailments. However, the potential roles of disulfidptosis-related genes (DRGs) in EMs remain elusive. This study aims to thoroughly explore the key disulfidptosis genes involved in EMs, and probe novel diagnostic markers and candidate therapeutic compounds from the aspect of disulfidptosis based on bioinformatics analysis, machine learning, and animal experiments.

RESULTS

Enrichment analysis on key module genes and differentially expressed genes (DEGs) of eutopic and ectopic endometrial tissues in EMs suggested that EMs was closely related to disulfidptosis. And then, we obtained 20 and 16 disulfidptosis-related DEGs in eutopic and ectopic endometrial tissue, respectively. The protein-protein interaction (PPI) network revealed complex interactions between genes, and screened nine and ten hub genes in eutopic and ectopic endometrial tissue, respectively. Furthermore, immune infiltration analysis uncovered distinct differences in the immunocyte, human leukocyte antigen (HLA) gene set, and immune checkpoints in the eutopic and ectopic endometrial tissues when compared with health control. Besides, the hub genes mentioned above showed a close correlation with the immune microenvironment of EMs. Furthermore, four machine learning algorithms were applied to screen signature genes in eutopic and ectopic endometrial tissue, including the binary logistic regression (BLR), the least absolute shrinkage and selection operator (LASSO), the support vector machine-recursive feature elimination (SVM-RFE), and the extreme gradient boosting (XGBoost). Model training and hyperparameter tuning were implemented on 80% of the data using a ten-fold cross-validation method, and tested in the testing sets which determined the excellent diagnostic performance of these models by six indicators (Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value, Accuracy, and Area Under Curve). And seven eutopic signature genes (ACTB, GYS1, IQGAP1, MYH10, NUBPL, SLC7A11, TLN1) and five ectopic signature genes (CAPZB, CD2AP, MYH10, OXSM, PDLIM1) were finally identified based on machine learning. The independent validation dataset also showed high accuracy of the signature genes (IQGAP1, SLC7A11, CD2AP, MYH10, PDLIM1) in predicting EMs. Moreover, we screened 12 specific compounds for EMs based on ectopic signature genes and the pharmacological impact of tretinoin on signature genes was further verified in the ectopic lesion in the EMs murine model.

CONCLUSION

This study verified a close association between disulfidptosis and EMs based on bioinformatics analysis, machine learning, and animal experiments. Further investigation on the biological mechanism of disulfidptosis in EMs is anticipated to yield novel advancements for searching for potential diagnostic biomarkers and revolutionary therapeutic approaches in EMs.

The effects of oral nutritional supplements on endometriosis-related pain: A narrative review of clinical studies

Endometriosis is a condition that can cause significant pain and discomfort for women, and the clinical and surgical treatments available have variable efficacy and can have adverse effects. These drawbacks often lead to poor adherence and therapeutic failure. Consequently, there has been increasing interest in the use of nutritional supplements as an adjuvant therapy for endometriosis. To facilitate clinical decision-making in managing women with endometriosis, a narrative review of clinical studies was conducted to investigate the effects of oral nutritional supplements on endometriosis-related pain. A literature search of the English-language PubMed/MEDLINE database was performed using appropriate keywords to identify clinical studies involving oral nutritional supplements and reporting on endometriosis-related pain. This narrative review included 20 studies published between 2013 and 2023, comprising 12 randomized controlled trials, six non-comparative trials, and two observational studies. The studies investigated the effects of various nutritional supplements on endometriosis-related pain, including vitamins, fatty acids, probiotics, medicinal plants, and bioactive compounds. A significant decrease in endometriosis-related pain was found in three out of five studies on vitamins, four out of six studies on fatty acids, one study on probiotics, two studies on medicinal plants, and five out of six studies on bioactive compounds. These nutritional supplements exhibited diverse biological activities, such as anti-inflammatory, antioxidant, antiproliferative, and antiangiogenic effects, all of which are relevant for managing endometriosis. These findings suggest that oral nutritional supplements could be included as part of a multidisciplinary treatment for endometriosis to decrease pain and enhance overall medical treatment.

Unraveling the relationship between gut microbiota and site-specific endometriosis: a Mendelian randomization analysis

Background

Although numerous studies have illustrated the connection between gut microbiota and endometriosis, a conspicuous gap exists in research focusing on the pathogenesis of endometriosis at various sites and its linkage with infertility.

Methods

In this study, we used a two-sample Mendelian randomization analysis to investigate the effect of gut microbiota on the development of endometriosis in different regions, including the uterus, ovary, fallopian tube, pelvic peritoneum, vagina, and rectovaginal septum, as well as the intestine. Additionally, we explored the correlation between gut microbiota and endometriosis-induced infertility. Genetic associations with gut microbes were obtained from genome-wide association study (GWAS) datasets provided by the MiBioGen consortium, whereas endometriosis-related GWAS data were sourced from the FinnGen dataset. In our analysis, single-nucleotide polymorphisms were used as instrumental variables, with the primary estimation of the causal effect performed via the inverse variance weighting method. Our sensitivity analyses incorporated heterogeneity tests, pleiotropy tests, and the leave-one-out method.

Results

We identified associations at the genus level between four bacterial communities and endometriosis. Subsequently, several associations between the gut microbiota and various subtypes of endometriosis at different anatomical sites were recognized. Specifically, three genera were linked with ovarian endometriosis, six genera were associated with tubal endometriosis, four genera showed links with pelvic peritoneum endometriosis, five genera were connected with vaginal and rectovaginal septum endometriosis, and seven genera demonstrated linkages with intestinal endometriosis. Additionally, one genus was associated with adenomyosis, and three genera exhibited associations with endometriosis-induced infertility.

Conclusion

Our study elucidates associations between gut microbiota and site-specific endometriosis, thereby augmenting our understanding of the pathophysiology of endometriosis. Moreover, our findings pave the way for potential therapeutic strategies targeting gut microbiota for individuals grappling with endometriosis-related infertility.

Immune micro-environment analysis and drug screening for ovarian endometriosis

BACKGROUND

Patients of ovary endometriosis have an abnormal immune micro-environment, leading to endometrial tissue that from retrograde menstruation evade immune surveillance and subsequently develop into ectopic lesions.

OBJECTIVE

This study aims to elucidate the crucial immune cells and molecular pathways that are associated with an aberrant immune micro-environment of endometriosis.

METHOD

In this study, we identified differentially expressed genes between ovarian ectopic endometrial tissue (OVE) and eutopic endometrial tissue from patients with endometriosis (PE) and non-endometriosis patients (CON) by analyzing the mRNA sequencing data. Additionally, we used WGCNA(Weighted Gene Co-expression Network Analysis) to screen for key genes related to immune cell infiltration and compared the sub-types of infiltrating immune cells using CIBERSORT(cell-type identification by estimating relative subsets of RNA transcript). Subsequently, we conducted a single-cell analysis on the identified key genes. Furthermore, we analyzed potential drugs suitable for ovarian endometriosis treatment using pRRophertic.

RESULTS

Seven key genes associated with immune cell infiltration were screened out. The expression of these genes in OVE was significantly lower than that in PE and CON. These key genes were mainly enriched in the NK cell-mediated cytotoxicity pathway, especially for CD16 + CD56dim NK. Moreover, NK cells infiltration in ovarian endometriosis was significantly reduced compared with PE and CON, while M2 macrophage shown the opposite. Results of the single-cell analysis showed that the expression of the seven key genes in NK cells and monocyte-macrophages in OVE was significantly lower than that in PE or CON. Additionally, we identified potential drugs suitable for ovarian endometriosis treatment.

CONCLUSION

The decreased infiltration of NK cells and increased infiltration of M2 macrophages contribute to the evasion of immune surveillance against endometrial tissue, promoting the progression of OVE. Therefore, potential strategies for the treatment of OVE include increasing NK cell activation and decreasing M2 macrophage polarization.

Reflections on the complex mechanisms of endometriosis from the perspective of ferroptosis

Ferroptosis is a novel type of iron-dependent programmed cell death characterised by intracellular iron overload, increased lipid peroxidation and abnormal accumulation of reactive oxygen species.It has been implicated in the progression of several diseases including cancer, ischaemia-reperfusion injury, neurodegenerative diseases and liver disease. The etiology of endometriosis (EMS) is still unclear and is associated with multiple factors, often accompanied by various forms of cell death and a complex microenvironment. In recent decades, the role of non-traditional forms of cell death, represented by ferroptosis, in endometriosis has come to the attention of researchers. This article reviews the transitional role of iron homeostasis in the development of ferroptosis, the characteristics and regulatory mechanisms of ferroptosis, and focuses on summarising the links between iron death and various pathogenic mechanisms of EMS, including oxidative stress, dysregulation of lipid metabolism, inflammation, autophagy and epithelial-mesenchymal transition. The possible applications of ferroptosis in the treatment of EMS, future research directions and current issues are discussed with the aim of providing new ideas for further understanding of EMS.

The Impacts of Inflammatory and Autoimmune Conditions on the Endometrium and Reproductive Outcomes

Background: A healthy pregnancy begins with an adequate endometrial state, even before the arrival of a blastocyst. Proper endometrial priming and the development of a tolerogenic decidua are key steps in creating the perfect environment for implantation and pregnancy. In these processes, the involvement of the maternal immune system seems to be of great relevance, modulating the different decidual immune populations to prepare the endometrium for a potential pregnancy. However, certain local pathologies of an inflammatory and autoimmune nature appear to have a direct impact on these phenomena, thus altering patients' reproductive outcomes. Methods: This literature review analyzes original articles, reviews, systematic reviews, and meta-analyses published between 1990 and 2024, concerning the impact of different inflammatory and autoimmune conditions on endometrial status and fertility. The included papers were obtained from Medline (Pubmed) and the Cochrane library. Results: There is evidence that endometriosis, adenomyosis, and chronic endometritis, through the promotion of a chronic inflammatory environment, are capable of altering endometrial immune populations, and, thus, processes essential for early pregnancy. Among other effects, these conditions have been linked to impaired decidualization, alterations in progesterone responsiveness, and hindered placentation. Similarly, antiphospholipid syndrome (APS), thyroid dysfunction, diabetes, and other pathologies related to glucose and gluten metabolism, due to their autoimmune nature, also appear to have a local impact on the uterine environment, affecting reproductive success through different mechanisms, including altered hormonal response and, again, impaired decidualization. Conclusions: The management of inflammatory and autoimmune diseases in assisted reproduction patients is gaining importance due to their direct impact on the endometrium. It is necessary to follow current expert recommendations and established therapeutic approaches in order to improve patients' prospects, ranging from antibiotic treatment in chronic endometritis to heparin and aspirin in APS, as well as hormonal treatments for endometriosis/adenomyosis or a gluten-free diet in celiac disease. All of them and the rest of the therapeutic perspectives, both current and under investigation, are presented throughout this work, assessing the possible improvements for reproductive outcomes.

Endometriosis is a disease of immune dysfunction, which could be linked to microbiota

Background: Endometriosis, characterized by extrauterine endometrial tissue, leads to irregular bleeding and pelvic pain. Menstrual retrograde theory suggests fragments traverse fallopian tubes, causing inflammation and scar tissue. Prevalent among infertile women, risk factors include fewer pregnancies, delayed childbirth, irregular cycles, and familial predisposition. Treatments, medication, and surgery entail side effects. Studies link gut microbiota alterations to endometriosis, necessitating research to establish causation. We used Mendelian randomization to investigate the potential link between endometriosis and gut microbiota through genetic variants. Methods: Two-sample Mendelian randomization analyzed gut microbiota's potential causal effects on endometriosis. Instrumental variables, robustly associated with exposures, leveraged GWAS data from MiBioGen for gut microbiota and FinnGen R8 release for endometriosis. SNPs strongly associated with exposures were instrumental variables. Rigorous assessments ensured SNP impact scrutiny on endometriosis. Results: At the genus level, Anaerotruncus, Desulfovibrio, Haemophilus, and Holdemania showed causal association with endometriosis. Specific gut microbiota exhibited causal effects on different endometriosis stages. Holdemania and Ruminococcaceae UCG002 exerted reversible, stage-specific impacts. Conclusion: Mendelian randomization provides evidence for the causal link between specific gut microbiotas and endometriosis, emphasizing the pivotal role of gut microbiota dysbiosis. Modulating gut microbiota emerges as a promising strategy for preventing and treating endometriosis.

Activation of cGAS/STING Drives Inflammation and Cellular Senescence of Macrophages in Ovarian Endometrioma Induced by Endometriotic Cyst Fluid

Ovarian endometrioma (OE) is a common gynecological condition characterized by the formation of "chocolate cysts". Recent research indicates that the cyst fluid acts as a "toxic environment" for the ovary and plays a significant role in the development of OE, with macrophages being pivotal. However, the specific molecular and cellular mechanisms of it are not fully understood. In this study, clinical samples are integrated, single-cell sequencing, in vivo and in vitro experimental models to comprehensively investigate the effects of OE fluid on ovarian function and the mechanisms of it. Combined with bioinformatics analysis and experimental validation, the findings demonstrate that OE fluid can cause ovarian function decline, which associated with inflammatory response, and mitochondrial dysfunction and cellular senescence, while activating the cGAS/STING signaling pathway. As a STING inhibitor, H-151 effectively alleviates ovarian dysfunction, inflammatory state and cell apoptosis induced by OE fluid. Furthermore, it is also discovered that H-151 can inhibit OE fluid-induced mitochondrial dysfunction and cellular senescence. These findings provide important theoretical and experimental foundations for further research and development of STING inhibitors as potential drugs for treating ovarian dysfunction.

Exploring the link: Systemic immune-inflammation index as a marker in endometriosis-Insights from the NHANES 2001-2006 cross-sectional study

OBJECTIVE

The systemic immuno-inflammatory index (SII), a novel immune marker of inflammation, has not been previously associated with endometriosis. The objective of this research is to explore the link between SII and the occurrence of endometriosis.

METHODS

Utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2001 to 2006, we screened and extracted relevant information from the population. Participants missing data on either SII or endometriosis were excluded. We divided the remaining cohort into quartiles based on SII levels: Q1 (SII < 249, n = 848), Q2 (249 ≤ SII < 604.55, n = 847), Q3 (604.55 ≤ SII < 825.35, n = 847), and Q4 (SII ≥ 852.35, n = 848). Multiple linear regression and smooth curve fitting techniques, were to evaluate the non-linear association between SII and endometriosis.

RESULTS

The study included 3,390 adults aged 20 to 55. Multiple linear regression analysis revealed a significant positive correlation between SII and endometriosis [3.14, 95% CI (2.22, 4.45), P < 0.01]. This correlation was consistent across subgroups defined by marital status, poverty income ratio, BMI, alcohol consumption, and age at first menstrual period. However, the relationship between SII and endometriosis was significantly modified by age, education, and history of pregnancy in the stratified analyses. The curve fitting indicated an S-shaped curve, with an inflection point at SII = 1105.76.

CONCLUSION

The SII may serve as a predictive marker for endometriosis risk among women in the United States, offering a potentially simple and cost-effective approach. However, given the cross-sectional design of this investigation, further validation in prospective studies is necessary.

Therapeutic effect of human umbilical cord mesenchymal stem cells and their conditioned medium on LPS-induced endometritis in mice

AIM

To explore the effect of human umbilical cord mesenchymal stem cells (hUC-MSCs) and their conditioned medium (MSC-CM) in repairing the endometritis mouse model in vivo.

METHODS

Lipopolysaccharide (LPS) was used to induce acute inflammation in endometritis mouse model. Mice were treated in six groups: control group (PBS), model group (LPS), LPS+MSC-CM (6 h) group, LPS+MSC-CM (12 h) group, LPS+MSCs (6 h) group and LPS+MSCs (12 h) group. Morphological and histological changes of mouse uterus were observed, and mouse uterine inflammation index myeloperoxidase (MPO) and related immune index TNF-α, IL-6 and IL-1β levels were detected by ELISA.

RESULTS

There exist remarkable inflammatory response and an obvious increase in the value of MPO, TNF-α, IL-1β and IL-6 in the endometritis mouse model compared with the control group. Morphological and histological appearances were relieved after treated with hUC-MSCs and MSC-CM. Besides, the value of MPO, TNF-α, IL-1β and IL-6 showed different degrees of decline. In comparison with LPS+MSC-CM (12 h) and LPS+MSCs (12 h) group, there was significant decrease in inflammatory indicators in LPS+MSC-CM (6 h) and LPS+MSCs (6 h) group.

CONCLUSIONS

Intrauterine infusion of hUC-MSCs and MSC-CM can alleviate LPS induced endometritis.

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.

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 role of regulatory T-cells in the development of endometriosis

Endometriosis is a benign disease of the female reproductive tract, characterized by the process of chronic inflammation and alterations in immune response. It is estimated to affect 2-19% of women in the general population and is commonly associated with symptoms of chronic pelvic pain and infertility. Regulatory T cells (Treg) are a subpopulation of T lymphocytes that are potent suppressors of inflammatory immune response, essential in preventing destructive immunity in all tissues. In endometriosis, several studies have investigated the possible role of Treg cells in the development of the disease. Most studies to date are heterogeneous in methodology and are based on a small number of cases, which means that it is impossible to define their exact role at present. Based on current knowledge, it seems that disturbed Treg homeostasis, leading to increased systemic and local inflammation within ectopic and eutopic endometrium, is present in women who eventually develop endometriosis. It is also evident that different subsets of human Treg cells have different roles in suppressing the immune response. Recent studies in patients with endometriosis have investigated naive/resting FOXP3lowCD45RA+ Treg cells, which upon T cell receptor stimulation, differentiate into activated/effector FOXP3highCD45RA- Treg cells, characterized by a strong immunosuppressive activity. In addition, critical factors controlling expression of Treg/effector genes, including reactive oxygen species and heme-responsive master transcription factor BACH2, were found to be upregulated in endometriotic lesions. As shown recently for cancer microenvironments, microbial inflammation may also contribute to the local composition of FOXP3+ subpopulations in endometriotic lesions. Furthermore, cytokines, such as IL-7, which control the homeostasis of Treg subsets through the tyrosine phosphorylation STAT5 signalling pathway, have also been shown to be dysregulated. To better understand the role of Treg in the development of endometriosis, future studies should use clear definitions of Tregs along with specific characterization of the non-Treg (FOXP3lowCD45RA-) fraction, which itself is a mixture of follicular Tregs and cells producing inflammatory cytokines.

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.

The Dysregulated IL-23/TH17 Axis in Endometriosis Pathophysiology

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

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.

Mining phase separation-related diagnostic biomarkers for endometriosis through WGCNA and multiple machine learning techniques: a retrospective and nomogram study

OBJECTIVE

The objective of this study was to investigate the role of phase separation-related genes in the development of endometriosis (EMs) and to identify potential characteristic genes associated with the condition.

METHODS

We used GEO database data, including 74 non-endometriosis and 74 varying-degree EMs patients. Our approach involved identifying significant gene modules, exploring gene intersections, identifying core genes, and screening for potential EMs biomarkers using weighted gene co-expression network analysis (WGCNA) and various machine learning approaches. We also performed gene set enrichment analysis (GSEA) to understand relevant pathways. This comprehensive approach helps investigate EMs genetics and potential biomarkers.

RESULTS

Nine genes were identified at the intersection, suggesting their involvement in EMs. GSEA linked DEGs to pathways like complement and coagulation cascades, DNA replication, chemokines, apical plasma membrane processes, and diseases such as Hepatitis B, Human T-cell leukemia virus 1 infection, and COVID-19. Five feature genes (FOS, CFD, CCNA1, CA4, CST1) were selected by machine learning for an effective EMs diagnostic nomogram. GSEA indicated their roles in mismatch repair, cell cycle regulation, complement and coagulation cascades, and IL-17 inflammation. Notable differences in immune cell proportions (CD4 T cells, CD8 T cells, DCs, macrophages) were observed between normal and disease groups, suggesting immune involvement.

CONCLUSIONS

This study suggests the potential involvement of phase separation-related genes in the pathogenesis of endometriosis (EMs) and identifies promising biomarkers for diagnosis. These findings have implications for further research and the development of new therapeutic strategies for EMs.

Association of endometriosis with asthma: a study of the NHANES database in 1999-2006

OBJECTIVE

Asthma is a chronic inflammatory disease of the airways with a gender differences in the prevalence after puberty. Recent studies have reported a relationship between asthma and endometriosis, possibly related to the immune response mechanisms, but the evidences are limited and inconsistent. Herein, this research aimed to investigate the association of endometriosis with asthma based on the representative population in the United States (U.S.) to provide some reference for further exploration on mechanism of gender difference in asthma.

METHODS

In this cross-sectional study, data of women aged ≥ 20 years old were extracted from the National Health and Nutrition Examination Survey (NHANES) database in 1999-2006. Weighted univariate and multivariate logistic regression analyses were utilized to explore the association of endometriosis with asthma. The multivariate models adjusted for covariates including age, race, education level, marital status, poverty income ratio (PIR), body mass index (BMI), waist circumference, smoking, estrogen and progesterone hormones use, uterine fibroids, at least one ovary removed, and birth control pills intake. The evaluation indexes were odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup analyses of age, race, BMI, and pregnancy history were also performed.

RESULTS

Among 5,556 eligible women, 782 had asthma, and 380 had endometriosis. The average age of participants was 37.19 years old, and more than half of them were non-Hispanic White (68.44%). After adjusting for covariates, endometriosis was associated with higher odds of asthma compared with non-endometriosis [OR = 1.48, 95%CI: (1.10-1.99)]. This relationship was also found in 40-49 years old [OR = 2.26, 95%CI: (1.21-4.23)], BMI of 25-29.9 kg/m2 [OR = 2.87, 95%CI: (1.52-5.44)], and pregnancy history [OR = 1.44, 95%CI: (1.01-2.06)] subgroups.

CONCLUSION

Endometriosis had a positive association with asthma in adult women. Females aged 40-49 years old, with BMI of 25-29.9 kg/m2 and had a history of pregnancy should take care about monitoring endometriosis to reduce the potential risk of asthma. Further studies are still needed to clarify the causal association between endometriosis and asthma.

NSUN2-Mediated m5C Methylation Impairs Endometrial Receptivity

Impaired endometrial decidualization is the primary cause of recurrent implantation failure (RIF). RNA methylation modification, especially NSUN family mediated m5C, is crucial for various physiological events, such as maternal-to-zygotic transition, gametogenesis, embryonic development, organismal lifespan, and cell cycle. However, the regulatory mechanisms between NSUN family mediated m5C modification and RIF remain unknown. We acquired NSUN2 expression data of 15 human endometrium samples at proliferative and secretory stages from reproductive cell atlas. The overall pattern of m5C sites and genes was elucidated through m5C-BS-seq, whereas the overall m5C levels in different groups were revealed by dot blot assay. BrdU and western blotting assays were carried out to evaluate the role of NSUN2 in proliferation and autophagy. The effects of NSUN2-mediated m5C modification on embryo attachment were evaluated by an in vitro model of a confluent monolayer of Ishikawa cells cocultured with BeWo spheroids, and its downstream targets were evaluated by real-time reverse-transcription PCR and western blotting in Ishikawa cells. The molecular mechanism for NSUN2 regulating its downstream targets' expression was determined by Cut&Tag and coimmunoprecipitation assays. NSUN2 was increased in SOX9+ cells and widespread in epithelial cell type at the proliferative stage by previous single-cell RNA sequencing data. NSUN2 overexpression (NSUN2OE) in the Ishikawa cell line elevated m5C levels and promoted cell proliferation and autophagy. NSUN2OE reduced attachment efficiency of BeWo cell spheres. Overexpressed NSUN2 was found to increase STAT1 and MMP14 mRNA expressions by inducing exon skipping. NSUN2 interacted with CLDN4 through m5C modification, and NSUN2OE or NSUN2 knockdown resulted in a similar variation tendency of CLDN4. Overexpression of NSUN2 increased CLDN4 H3K9ac modification by downregulating SIRT4 expression at the protein level, leading to the upregulation of CLDN4 mRNA expression. Our results uncovered a novel intricate regulatory mechanism between NSUN2-mediated m5C and RIF and suggested a potential new therapeutic strategy for RIF.

NK cell receptor profiling of endometrial and decidual NK cells reveals pregnancy-induced adaptations

Natural killer (NK) cells, with a unique NK cell receptor phenotype, are abundantly present in the non-pregnant (endometrium) and pregnant (decidua) humanuterine mucosa. It is hypothesized that NK cells in the endometrium are precursors for decidual NK cells present during pregnancy. Microenvironmental changes can alter the phenotype of NK cells, but it is unclear whether decidual NK cell precursors in the endometrium alter their NK cell receptor repertoire under the influence of pregnancy. To examine whether decidual NK cell precursors reveal phenotypic modifications upon pregnancy, we immunophenotyped the NK cell receptor repertoire of both endometrial and early-pregnancy decidual NK cells using flow cytometry. We showed that NK cells in pre-pregnancy endometrium have a different phenotypic composition compared to NK cells in early-pregnancy decidua. The frequency of killer-immunoglobulin-like receptor (KIR expressing NK cells, especially KIR2DS1, KIR2DL2L3S2, and KIR2DL2S2 was significantly lower in decidua, while the frequency of NK cells expressing activating receptors NKG2D, NKp30, NKp46, and CD244 was significantly higher compared to endometrium. Furthermore, co-expression patterns showed a lower frequency of NK cells co-expressing KIR3DL1S1 and KIR2DL2L3S2 in decidua. Our results provide new insights into the adaptations in NK cell receptor repertoire composition that NK cells in the uterine mucosa undergo upon pregnancy.

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.

ATG8 inhibited endometriosis formation by regulating Treg cells differentiation via integrin α4β1 and Talin-1 interaction

RESEARCH QUESTION

What is the relationship between ATG8 and integrin α4β1, Talin-1, and Treg cell differentiation, and the effects on endometriosis (EMS)?

DESIGN

First, the correlation between the ATG8, Talin-1, integrin α4β1, and differentiation of Treg cells and EMS was examined in clinical samples. Human peripheral blood mononuclear cells (PBMC) and endometrial stromal cells were extracted and identified, oe-ATG8 and oe-integrin α4β1 were transfected to overexpress ATG8 and integrin α4β1, and Tregs cell differentiation and endometrial stromal cells (ESC) function were detected. In addition, the molecular mechanism by which ATG8 inhibited EMS disease progression at the molecular and animal levels was investigated.

RESULTS

ATG8 expression was negatively correlated with positive proportion of Tregs cells (P = 0.0463). The expression of Talin-1 and integrin-α4β1 (both P < 0.0001) in PBMC decreased significantly after oe-ATG8 transfection, whereas the Treg cells' positive rate significantly increased (P = 0.0003). The ESC proliferation, adhesion, migration, and invasion (all P < 0.0001) declined after co-culture with Treg cells that underwent oe-ATG8 transfection. The expression of Talin-1 (P = 0.0025) and integrin-α4β1 (P = 0.0002) in PBMC increased significantly after oe-integrin α4β1 and oe-ATG8 transfection. In addition, this transfection reversed the corresponding regulation of oe-ATG8 transfection. Finally, animal experiments in vivo confirmed that ATG8 inhibited EMS disease progression.

CONCLUSION

The ATG8 regulated Treg cell differentiation and inhibited EMS formation by influencing the interaction between integrin α4β1 and Talin-1.

Pollution and endometriosis: A deep dive into the environmental impacts on women's health

BACKGROUND

The interaction between pollution and endometriosis is a pressing issue that demands immediate attention. The impact of pollution, particularly air and water pollution, or occupational hazards, on hormonal disruption and the initiation of endometriosis remains a major issue.

OBJECTIVES

This narrative review aims to delve into the intricate connection between pollution and endometriosis, shedding light on how environmental factors contribute to the onset and severity of this disease and, thus, the possible public health policy implications.

DISCUSSION

Endocrine-disrupting chemicals (EDCs) in pollutants dysregulate the hormonal balance, contributing to the progression of this major gynaecological disorder. Air pollution, specifically PM2.5 and PAHs, has been associated with an increased risk of endometriosis by enhancing chronic inflammation, oxidative stress, and hormonal imbalances. Chemical contaminants in water and work exposures, including heavy metals, dioxins, and PCBs, disrupt the hormonal regulation and potentially contribute to endometriosis. Mitigating the environmental impact of pollution is required to safeguard women's reproductive health. This requires a comprehensive approach involving stringent environmental regulations, sustainable practices, responsible waste management, research and innovation, public awareness, and collaboration among stakeholders.

CONCLUSION

Public health policies have a major role in addressing the interaction between pollution and endometriosis in a long-term commitment.

Angiogenesis signaling in endometriosis: Molecules, diagnosis and treatment (Review)

Endometriosis (EM) is one of the most common diseases among women of reproductive age. The etiology and pathogenesis of EM remain unclear and therefore there is a lack of effective treatment measures, which affects physical and mental health, as well as the quality of life of patients with EM. Angiogenesis has become a hotspot for research on the pathogenesis of EM; the role of angiogenesis‑related serological markers and anti‑angiogenic therapy in the diagnosis and treatment of EM is promising for early diagnosis and treatment of EM. Angiogenesis in EM is subject to complex regulation by hormones, immunity and associated cytokines. Therefore, novel targets for angiogenesis therapy are also being discovered and developed. The present review summarized the pathological mechanisms of angiogenesis and the value of relevant markers in pathogenesis and diagnosis of EM, along with the status of research on anti‑angiogenic drugs in the treatment of EM. The role of angiogenesis in EM provides an important reference for treatment and diagnosis, but there is no uniform non‑invasive diagnostic marker and proven strategy for anti‑angiogenesis.

PI3K/AKT signaling pathway associates with pyroptosis and inflammation in patients with endometriosis

Endometriosis (EMS) is known to be closely associated with inflammation. We evaluate the possible mechanism linking the PI3K/AKT signaling pathway with pyroptosis and inflammation in EMS. We collected 30 patients undergoing laparoscopic for endometriosis as the EMS group and those undergoing surgery for uterine fibroids as the control group, from whom we collected serum, normal endometrium, eutopic endometrium and ectopic endometrium. Transmission electron microscopy (TEM) was used to observe the internal structure of endometrial cells. Western Blot was used to detect the protein expression of PI3K, P-PI3K, AKT, P-AKT, NLRP3, Caspase-1, GSDMD, and GSDMD-N. Immunohistochemistry (IHC) staining was used to detect the expression of PI3K, AKT, NLRP3, Caspase-1, GSDMD, and GSDMD-N proteins. Immunofluorescence (IF) staining was used to observe the expression of GSDMD-N. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to analyze the mRNA levels of PI3K, AKT, NLRP3, Caspase-1, GSDMD, and GSDMD-N. ELISA was used to detect serum levels of IL-1β, IL-18, TLR4, and NF-κB. We found that activation of PI3K/AKT signaling pathway in endometriosis significantly increased the level of cellular pyroptosis and inflammatory factors. Our results suggest that there is a positive correlation between the PI3K/AKT signaling pathway and pyroptosisas well as inflammation in EMS patients.

Unraveling the microbial puzzle: exploring the intricate role of gut microbiota in endometriosis pathogenesis

Endometriosis (EMs) is a prevalent gynecological disorder characterized by the growth of uterine tissue outside the uterine cavity, causing debilitating symptoms and infertility. Despite its prevalence, the exact mechanisms behind EMs development remain incompletely understood. This article presents a comprehensive overview of the relationship between gut microbiota imbalance and EMs pathogenesis. Recent research indicates that gut microbiota plays a pivotal role in various aspects of EMs, including immune regulation, generation of inflammatory factors, angiopoietin release, hormonal regulation, and endotoxin production. Dysbiosis of gut microbiota can disrupt immune responses, leading to inflammation and impaired immune clearance of endometrial fragments, resulting in the development of endometriotic lesions. The dysregulated microbiota can contribute to the release of lipopolysaccharide (LPS), triggering chronic inflammation and promoting ectopic endometrial adhesion, invasion, and angiogenesis. Furthermore, gut microbiota involvement in estrogen metabolism affects estrogen levels, which are directly related to EMs development. The review also highlights the potential of gut microbiota as a diagnostic tool and therapeutic target for EMs. Interventions such as fecal microbiota transplantation (FMT) and the use of gut microbiota preparations have demonstrated promising effects in reducing EMs symptoms. Despite the progress made, further research is needed to unravel the intricate interactions between gut microbiota and EMs, paving the way for more effective prevention and treatment strategies for this challenging condition.

Establishment and comparison of different procedures for modeling intrauterine adhesion in rats: A preliminary study

The establishment of a stable animal model for intrauterine adhesion (IUA) can significantly enhance research on the pathogenesis and pathological changes of this disease, as well as on the development of innovative therapeutic approaches. In this study, three different modeling methods, including phenol mucilage combined mechanical scraping, ethanol combined mechanical scraping and ethanol modeling alone were designed. The morphological characteristics of the models were evaluated. The underlying mechanisms and fertility capacity of the ethanol modeling group were analyzed and compared to those of the sham surgery group. All three methods resulted in severe intrauterine adhesions, with ethanol being identified as a reliable modeling agent and was subsequently subjected to further evaluation. Immunohistochemistry and RT-PCR results indicated that the ethanol modeling group exhibited an increase in the degree of fibrosis and inflammation, as well as a significant reduction in endometrial thickness, gland number, vascularization, and endometrial receptivity, ultimately resulting in the loss of fertility capacity. The aforementioned findings indicate that the intrauterine perfusion of 95 % ethanol is efficacious in inducing the development of intrauterine adhesions in rats. Given its cost-effectiveness, efficacy, and stability in IUA formation, the use of 95 % ethanol intrauterine perfusion may serve as a novel platform for evaluating innovative anti-adhesion materials and bioengineered therapies.

Exosomes from ectopic endometrial stromal cells promote M2 macrophage polarization by delivering miR-146a-5p

BACKGROUND

Ectopic endometrial stromal cells (ESCs) and M2 macrophages co-exist in the lesions of endometriosis and participate in the occurrence and progression of endometriosis. However, the interaction between ectopic ESCs and M2-type macrophage polarization is poorly understood. This study aims to investigate the effect of exosomes released from ectopic ESCs on M2 macrophage polarization and the potential mechanism.

METHODS

Human THP-1 monocytic cells induced macrophage differentiation (M0) and M2 polarization. Ectopic ESCs and their exosomes were used to stimulate M2 macrophages. M2 macrophage polarization was examined by detecting CD163 and ARG1 expression. Exosomal microRNAs were analyzed by small-RNA sequencing.

RESULTS

Our in vitro results suggest that exosomes of ectopic ESCs promoted M2 macrophage polarization. Meanwhile, The miR-146a-5p level was highly increased in ectopic ESCs and their exosomes and promoted the role of exosomes in M2 macrophage polarization. As a target, TRAF6 overexpression inhibits the function of miR-146a-5p mimic on M2 macrophage polarization. In the rat model, exosomes from ectopic ESCs contribute to the development of endometriosis.

CONCLUSIONS

It was suggested that exosomes derived from ectopic ESCs promote the M2 macrophage polarization by delivering miR-146a-5p targeting TRAF6 in the pathological process of endometriosis.

Vaginal Bacteria Elicit Acute Inflammatory Response in Fallopian Tube Organoids

To facilitate in vitro mechanistic studies in pelvic inflammatory disease and subsequent tubal factor infertility, we sought to establish patient tissue derived fallopian tube (FT) organoids and to study their inflammatory response to acute vaginal bacterial infection. FT tissues were obtained from four patients after salpingectomy for benign gynecological diseases. We introduced acute infection in the FT organoid culture system by inoculating the organoid culture media with two common vaginal bacterial species, Lactobacillus crispatus and Fannyhessea vaginae. The inflammatory response elicited in the organoids after acute bacterial infection was analyzed by the expression profile of 249 inflammatory genes. Compared to the negative controls that were not cultured with any bacteria, the organoids cultured with either bacterial species showed multiple differentially expressed inflammatory genes. Marked differences were noted between the Lactobacillus crispatus infected organoids and those infected by Fannyhessea vaginae. Genes from the C-X-C motif chemokine ligand (CXCL) family were highly upregulated in Fannyhessea vaginae infected organoids. Flow cytometry showed that immune cells quickly disappeared during the organoid culture, indicating the inflammatory response observed with bacterial culture was generated by the epithelial cells in the organoids. In summary, we have shown that patient tissue derived FT organoids respond to acute bacterial infection with upregulation of inflammatory genes specific to different vaginal bacterial species. FT organoids is a useful in vitro model system to study the host-pathogen interaction during bacterial infection.

Extracellular succinate derived from ectopic milieu drives adhesion and implantation growth of ectopic endometrial stromal cells via the SUCNR1 signal in endometriosis

BACKGROUND

As a dual-function metabolite, succinate has emerged in cell function and plays a key signaling role in linking mitochondrial function to other cellular functions. Succinate accumulation in the cytoplasm is commonly associated with hypoxia in the microenvironment and immune cell activation. Extracellular succinate released into the microenvironment is considered an inflammatory alarm that can be sensed by its membrane receptor SUCNR1, which boosts proinflammatory responses and acts akin to classical hormones and cytokines. Succinate plays an important role in the development of inflammatory diseases. Whether succinate facilitates the progression of endometriosis (EMs), characterized by chronic inflammation and peritoneal adhesion, is worth exploring.

OBJECTIVE

We mimicked the ectopic milieu in vitro and in vivo to evaluate the main source and potential role of succinate in endometriosis. We assessed the molecular and functional effects of succinate on macrophages and peritoneal mesothelial cells in peritoneal cavity. The effect of succinate/SUCNR1 signaling on ectopic endometrial stromal cells (ESCs) was further explored in this study.

METHODS

In this study, we used targeted organic acid metabolomics analysis and in vitro assays to assess the potential accumulation of succinate in the peritoneal fluid of EMs patients. We examined its correlation with disease severity, Visual Analogue Scale, and the Endometriosis Fertility Index. Flow cytometry, enzyme linked immunosorbent assay, western blot assay, quantitative real-time PCR, and other molecular biology techniques were used to explore the potential mechanisms.

RESULTS

By mimicking the ectopic milieu, we constructed an in vitro co-culture system and found that M1 polarized macrophages and that the peritoneal mesothelial cell line (HMrSV5) mainly released succinate into their microenvironment and activated the succinate receptor (SUCNR1) signal, which further polarized the macrophages and significantly enhanced the invasive survival of ESCs, and the adhesion to the peritoneum. We further investigated the pathological effects of extracellular succinate in vivo using a xenograft mouse models of endometriosis.

CONCLUSIONS

Succinate-SUCNR1 signaling facilitates the creation of inflammatory cells and plays a vital role in EMs progression and peritoneal adhesion. Our work on the molecular mechanisms underlying succinate accumulation and function will help elucidate the phenotypic mysteries of pain and infertility in EMs. Video Abstract.

Emerging bacterial factors for understanding pathogenesis of endometriosis

The pathogenesis of endometriosis is a complex process, and recent research has introduced novel hypotheses in this field. This review summarizes recent studies on the pathogenesis of endometriosis. We focused on several classical hypotheses, as well as their interactions with the microenvironment of hormonal dependence and immunosuppression. Furthermore, we highlighted the emergence of bacterial factors associated with endometriosis. Recent advances in next-generation sequencing (NGS) have revealed the presence and detailed distribution of these bacteria as well as the involvement of specific bacteria in pathogenesis. These factors alter the microenvironment in the early stages of endometriosis development, leading to lesion formation. Understanding the mechanisms underlying the early development of endometriosis from a new perspective would be helpful for the development of novel therapeutic agents for endometriosis.

Inflammatory markers are associated with infertility prevalence: a cross-sectional analysis of the NHANES 2013-2020

BACKGROUND

Inflammation exerts a critical role in the pathogenesis of infertility. The relationship between inflammatory parameters from peripheral blood and infertility remains unclear. Aim of this study was to investigate the association between inflammatory markers and infertility among women of reproductive age in the United States.

METHODS

Women aged 20-45 were included from the National Health and Nutrition Examination Survey (NHANES) 2013-2020 for the present cross-sectional study. Data of reproductive status was collected from the Reproductive Health Questionnaire. Six inflammatory markers, systemic immune inflammation index (SII), lymphocyte count (LC), product of platelet and neutrophil count (PPN), platelet-lymphocyte ratio (PLR), neutrophil-lymphocyte ratio (NLR) and lymphocyte-monocyte ratio (LMR) were calculated from complete blood counts in mobile examination center. Survey-weighted multivariable logistic regression was employed to assess the association between inflammatory markers and infertility in four different models, then restricted cubic spline (RCS) plot was used to explore non-linearity association between inflammatory markers and infertility. Subgroup analyses were performed to further clarify effects of other covariates on association between inflammatory markers and infertility.

RESULTS

A total of 3,105 women aged 20-45 was included in the final analysis, with 431 (13.88%) self-reported infertility. A negative association was found between log2-SII, log2-PLR and infertility, with an OR of 0.95 (95% CI: 0.78,1.15; p = 0.60), 0.80 (95% CI:0.60,1.05; p = 0.10), respectively. The results were similar in model 1, model 2, and model 3. Compared with the lowest quartile (Q1), the third quartile (Q3) of log2-SII was negatively correlation with infertility, with an OR (95% CI) of 0.56 (95% CI: 0.37,0.85; p = 0.01) in model 3. Similarly, the third quartile (Q3) of log2-PLR was negatively correlation with infertility, with an OR (95% CI) of 0.61 (95% CI: 0.43,0.88; p = 0.01) in model 3. No significant association was observed between log2-LC, log2-PPN, log2-NLR, log2-LMR and infertility in model 3. A similar U-shaped relationship between log2-SII and infertility was found (p for non-linear < 0.05). The results of subgroup analyses revealed that associations between the third quartile (Q3) of log2-SII, log2-PLR and infertility were nearly consistent.

CONCLUSION

The findings showed that SII and PLR were negatively associated with infertility. Further studies are needed to explore their association better and the underlying mechanisms.

Macrophage membrane-decorated MnO2 nanozyme catalyzed the scavenging of estradiol for endometriosis treatment

Endometriosis (EMs) is an inflammatory, estrogen-dependent disease characterized by the growth of endometrial-like tissue outside the uterus. Despite many efforts to develop effective treatment regimens, the overall response to halting EMs progression so far remains unsatisfactory. Herein, we explored and synthesized a biomimic macrophage membrane-decorated MnO2 nanosheet (MM-NS) as a nanozyme capable of scavenging estrogen for EMs treatment. This nanosystem exhibited good solubility and potent estradiol scavenging activities. As expected, MM-NS effectively inhibited cell proliferation and inflammation in an estradiol scavenging-dependent way. In vivo MM-NS targeted to ectopic lesions and effectively suppressed lesion growth in endometriosis mice model, which could be attributed to the inhibition of tissue proliferation and the lower levels of inflammatory factors in peritoneal fluid. Taken together, this study not only revealed a new application scenario for nanozyme but also developed a novel endometriosis treatment strategy by catalyzing the scavenging of estrogen.