Estrobolome dysregulation is associated with altered immunometabolism in a mouse model of endometriosis

Endometriosis: A new perspective on epigenetics and oxidative stress

As a complex chronic gynecological disorder characterized by multifaceted etiology involving genetics, environment, immunity and inflammation, endometriosis (EM) has long been a significant concern for women of reproductive age worldwide. This review aimed to comprehensively examine the interplay between epigenetics and oxidative stress (OS) in the pathogenesis of EM. Through the integration of cutting-edge research, the response of OS signals to epigenetic modifications was explored. The microbiome exerts an influence on this causal regulatory relationship, and these mechanisms collectively contribute to the pathophysiology of EM. Specifically, this article highlighted the roles of epigenetics and OS in EM and underscored the importance of the microbiome as a regulatory link. A discussion was also held on the future directions of biomarkers and precision medicine, including the application prospects of epigenetic and OS markers in the diagnosis and treatment decision-making of EM, and innovations in therapeutic strategies like targeting epigenetic modifications and antioxidant therapies. Moreover, this review emphasized the potential of multi-omics integrated analysis to deepen the understanding of the disease, guide future therapeutic strategies and promote personalized medicine.

Peritoneal Endometriosis Impairs Ovarian Reserve and Increases Atresia in a Rat Model

Background/Objectives: Endometriosis has a marked impact on fertility, although the mechanisms behind this relationship remain poorly understood, particularly in cases without significant anatomical distortions or in the context of ovarian endometriomas. This study aimed to investigate the effect of peritoneal endometriosis on ovarian function by assessing ovarian reserve and apoptosis. Methods: Peritoneal endometriosis was surgically induced in Sprague Dawley rats through the autotransplantation of uterine fragments onto the bowel mesothelium. One month post-surgery, ovarian structures were counted, follicle and corpora lutea apoptosis was evaluated by TUNEL, and apoptotic-related protein expression in ovaries was assessed by Western blot. Additionally, a co-culture system using 12Z endometriotic and KGN granulosa cell lines was utilized to evaluate gene expression by RT-qPCR. Results: Rats with peritoneal endometriosis exhibited a significant reduction in ovarian structures characterized by a low number of total follicles, particularly primordial, primary, preantral, and late-antral follicles. Consistently, AMH protein expression was decreased in ovaries in the presence of endometriosis. In addition, this disease led to a significant increase in late-antral follicles that were TUNEL-positive and in the number of apoptotic cells in corpora lutea, indicating higher apoptosis in endometriosis ovaries. Concomitantly, the altered expression of apoptosis-related proteins was observed, with increased procaspase 3 and decreased BCL-2 expression. In addition, KGN granulosa cells co-cultured with 12Z endometriotic cells displayed reduced KITLG mRNA expression and increased AMHR2 mRNA expression. Conclusions: Peritoneal endometriosis significantly impairs ovarian health by disrupting folliculogenesis, reducing ovarian reserve, and increasing apoptosis, potentially accelerating ovarian aging and contributing to infertility. These results underscore the need for further research to identify the molecular pathways involved and to develop targeted therapeutic strategies.

Causal analysis of dietary preferences and the risk of endometriosis using large-scale population data

Dietary factors have recently been recognized as potentially influential in the pathogenesis of endometriosis (EM), yet studies on the causal relationship between dietary preferences and EM are limited. The present study aimed to explore the causal relationships between 187 dietary preferences and EM using Mendelian randomization (MR) methods. This study utilised genome-wide association study data from over 500,000 European participants for dietary preferences and 64,658 EM patients from Finland. Dietary preferences with potential causal relationships to EM were identified using two-sample MR methods. P-values from the inverse variance weighted (IVW) analysis were corrected using the false discovery rate (FDR) method to ensure accuracy. Additionally, heterogeneity analysis, pleiotropy assessment, leave-one-out analysis, and reverse MR analysis were conducted to further validate and solidify the findings of the study. After FDR correction, IVW analysis revealed that asparagus preference was significantly protective against EM, including in American Society for Reproductive Medicine (ASRM) stages 1-2 and 3-4. Conversely, preferences for different types of coffee and orange juice were associated with an increased likelihood of EM across these stages. Subgroup analysis indicated that asparagus preference had a protective effect against deep EM, ovarian EM, pelvic peritoneal EM, and rectovaginal septum and vaginal EM. In contrast, coffee preference increased the risk of pelvic peritoneal EM, fallopian tube EM, and unspecified EM, whereas orange juice preference increased the risk of deep EM, rectovaginal septum and vaginal EM, pelvic peritoneal EM, and unspecified EM. Reverse MR analysis did not identify causal relationships between EM and the specific dietary preferences that were analysed in this study. These findings suggest that asparagus preference significantly reduces the risk of developing EM, whereas preferences for orange juice and different types of coffee may increase the risk, offering new insights into EM management through dietary modifications.

The Current Applications of Metabolomics in Understanding Endometriosis: A Systematic Review

Endometriosis is a common gynecological disease that affects approximately 10-15% of reproductive-aged women worldwide. This debilitating disease has a negative impact on the quality of life of those affected. Despite this condition being very common, the pathogenesis is not well understood. Metabolomics is the study of the array of low-weight metabolites in a given sample. This emerging field of omics-based science has proved to be effective at furthering the understanding of endometriosis. In this systematic review, we seek to provide an overview of the application of metabolomics in endometriosis. We highlight the use of metabolomics in locating biomarkers for identification, understanding treatment mechanisms and symptoms, and relating external factors to endometriosis. The literature search took place in the Web of Science, Pubmed, and Google Scholar based on the keywords "metabolomics" AND "endometriosis" or "metabolome" AND "endometriosis". We found 58 articles from 2012 to 2024 that met our search criteria. Significant alterations of lipids, amino acids, as well as other compounds were present in human and animal models. Discrepancies among studies of significantly altered metabolites make it difficult to make general conclusions on the metabolic signature of endometriosis. However, several individual metabolites were elevated in multiple studies of women with endometriosis; these include 3-hydroxybutyrate, lactate, phosphatidic acids, succinate, pyruvate, tetradecenoylcarnitine, hypoxanthine, and xanthine. Accordingly, L-isoleucine and citrate were reduced in multiple studies of women with endometriosis. Including larger cohorts, standardizing testing methods, and studying the individual phenotypes of endometriosis may lead to more separable results.

Butyrate as a Potential Modulator in Gynecological Disease Progression

This review investigates the therapeutic potential of butyrate, a short-chain fatty acid (SCFA) produced by gut microbiota, in the prevention and treatment of various gynecological diseases, including polycystic ovary syndrome (PCOS), endometriosis, and gynecologic cancers like cervical and ovarian cancer. These conditions often pose treatment challenges, with conventional therapies offering limited and temporary relief, significant side effects, and a risk of recurrence. Emerging evidence highlights butyrate's unique biological activities, particularly its role as a histone deacetylase (HDAC) inhibitor, which allows it to modulate gene expression, immune responses, and inflammation. In PCOS, butyrate aids in restoring hormonal balance, enhancing insulin sensitivity, and reducing chronic inflammation. For endometriosis, butyrate appears to suppress immune dysregulation and minimize lesion proliferation. Additionally, in cervical and ovarian cancers, butyrate demonstrates anticancer effects through mechanisms such as cell cycle arrest, apoptosis induction, and suppression of tumor progression. Dietary interventions, particularly high-fiber and Mediterranean diets, that increase butyrate production are proposed as complementary approaches, supporting natural microbiota modulation to enhance therapeutic outcomes. However, butyrate's short half-life limits its clinical application, spurring interest in butyrate analogs and probiotics to maintain stable levels and extend its benefits. This review consolidates current findings on butyrate's multifaceted impact across gynecological health, highlighting the potential for microbiota-centered therapies in advancing treatment strategies and improving women's reproductive health.

The Critical Role of Host and Bacterial Extracellular Vesicles in Endometriosis

Endometriosis is a chronic, inflammatory, oestrogen-dependent disorder that is defined by the presence of endometrium-like tissue in the extra-uterine environment. It is estimated to affect approximately 10% of women of reproductive age, and the cause is still largely unknown. The heterogenous nature and complex pathophysiology of the disease results in diagnostic and therapeutic challenges. This review examines the emerging role of host extracellular vesicles (EVs) in endometriosis development and progression, with a particular focus on bacterial extracellular vesicles (BEVs). EVs are nano-sized membrane-bound particles that can transport bioactive molecules such as nucleic acids, proteins, and lipids, and therefore play an essential role in intercellular communication. Due to their unique cargo composition, EVs can play a dual role, both in the disease pathogenesis and as biomarkers. Both host and bacterial EVs (HEVs and BEVs) have been implicated in endometriosis, by modulating inflammatory responses, angiogenesis, tissue remodelling, and cellular proliferation within the peritoneal microenvironment. Understanding the intricate mechanisms underlying EVs in endometriosis pathophysiology and modulation of the lesion microenvironment may lead to novel diagnostic tools and therapeutic targets. Future research should focus on uncovering the specific cargo, the inter-kingdom cell-to-cell interactions, and the anti-inflammatory and anti-microbial mechanisms of both HEVs and BEVs in endometriosis in the hope of discovering translational findings that could improve the diagnosis and treatment of the disease.

Endometrial Dysbiosis: A Possible Association with Estrobolome Alteration

BACKGROUND/OBJECTIVES

Microbiota modification at the endometrial level can favor gynecological diseases and impair women's fertility. The overgrowth of pathogen microorganisms is related to the contemporary alteration of estrogen-metabolizing bacteria, including β-glucuronidase, thereby enhancing estrogen-related inflammatory states and decreasing anti-inflammatory cells. The possible connection between estrobolome impairment and gynecological diseases has been suggested in animal models. Nevertheless, in humans, coherent evidence on the estrobolome alteration and functionality of the female reproductive tract is still lacking. The objective of this study was to explore alterations in estrogen-related signaling and the putative link with endometrial dysbiosis.

METHODS

Women with infertility and repeated implantation failure (RIF, N = 40) were enrolled in order to explore the putative link between estrogen metabolism and endometrial dysbiosis. Endometrial biopsies were used to measure inflammatory and growth factor molecules. β-glucuronidase enzyme activity and estrogen receptor (ER) expression were also assessed.

RESULTS

Herein, increased levels of inflammatory molecules (i.e., IL-1β and HIF-1α) and decreased levels of the growth factor IGF-1 were found in the endometrial biopsies of patients presenting dysbiosis compared to eubiotic ones. β-glucuronidase activity and the expression of ERβ were significantly enhanced in patients in the dysbiosis group. Interestingly, Lactobacilli abundance was inversely related to β-glucuronidase activity and to ERβ expression, thus suggesting that an alteration of the estrogen-activating enzyme may affect the expression of ERs as well.

CONCLUSIONS

Overall, these preliminary data suggested a link between endometrial dysbiosis and estrobolome impairment as possible synergistic contributing factors to women infertility and RIF.

The gut microbiota: emerging biomarkers and potential treatments for infertility-related diseases

Infertility is a disease of impaired fertility. With socioeconomic development, changes in human lifestyles, and increased environmental pollution, the problem of low human fertility has become increasingly prominent. The incidence of global infertility is increasing every year. Many factors lead to infertility, and common female factors include tubal factors, ovulation disorders, endometriosis, and immune factors. The gut microbiota is involved in many physiological processes, such as nutrient absorption, intestinal mucosal growth, glycolipid metabolism, and immune system regulation. An altered gut flora is associated with female infertility disorders such as polycystic ovary syndrome (PCOS), endometriosis (EMs), and premature ovarian failure (POF). Dysbiosis of the gut microbiota directly or indirectly contributes to the development of female infertility disorders, which also affect the homeostasis of the gut microbiota. Identifying the etiology and pathogenesis of infertility in patients is the focus of reproductive medicine physicians. We studied the developmental mechanism between the gut microbiota and PCOS, EMs, and POF from a new perspective, providing new ideas for diagnosing and treating female infertility diseases and specific reference values for eugenics.

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

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

17β-Estradiol protects female rats from bilateral oophorectomy-induced nonalcoholic fatty liver disease induced by improving linoleic acid metabolism alteration and gut microbiota disturbance

After surgical or natural menopause, women face a high risk of nonalcoholic fatty liver disease (NAFLD), which can be diminished by hormone replacement therapy (HRT). The gut microbiota is subject to modulation by various physiological changes and the progression of diseases. This microbial ecosystem coexists symbiotically with the host, playing pivotal roles in immune maturation, microbial defense mechanisms, and metabolic functions essential for nutritional and hormone homeostasis. E2 supplementation effectively prevented the development of NAFLD after bilateral oophorectomy (OVX) in female rats. The changes in the gut microbiota such as abnormal biosynthetic metabolism of fatty acids caused by OVX were partially restored by E2 supplementation. The combination of liver transcriptomics and metabolomics analysis revealed that linoleic acid (LA) metabolism, a pivotal pathway in fatty acids metabolism was mainly manipulated during the induction and treatment of NAFLD. Further correlation analysis indicated that the gut microbes were associated with abnormal serum indicators and different LA metabolites. These metabolites are also closely related to serum indicators of NAFLD. An in vitro study verified that LA is an inducer of hepatic steatosis. The changes in transcription in the LA metabolism pathway could be normalized by E2 treatment. The metabolic perturbations of LA may directly and secondhand impact the development of NAFLD in postmenopausal individuals. This research focused on the sex-specific pathophysiology and treatment of NAFLD, providing more evidence for HRT and calling for the multitiered management of NAFLD.