Alpha-linolenic acid regulates the gut microbiota and the inflammatory environment in a mouse model of endometriosis

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

BACKGROUND

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

METHODS

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

FINDINGS

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

CONCLUSIONS

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

FUNDING

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

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.

Dietary α-linolenic acid supplementation enhances resistance to Salmonella Typhimurium challenge in chickens by altering the intestinal mucosal barrier integrity and cecal microbes

Salmonella is an important foodborne pathogen. Given the ban on the use of antibiotics during the egg-laying period in China, finding safe and effective alternatives to antibiotics to reduce Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) infections in chickens is essential for the prevention and control of this pathogen and the protection of human health. Numerous studies have shown that unsaturated fatty acids have a positive effect on intestinal inflammation and resistance to infection by intestinal pathogens. Here we investigated the protective effect of α-linolenic acid (ALA) against S. Typhimurium infection in chickens and further explored its mechanism of action. We added different proportions of ALA to the feed and observed the effect of ALA on S. Typhimurium colonization using metagenomic sequencing technology and physiological index measurements. The role of gut flora on S. Typhimurium colonization was subsequently verified by fecal microbiota transplantation (FMT). We found that ALA protects chickens from S. Typhimurium infection by reducing intestinal inflammation through remodeling the gut microbiota, up-regulating the expression of ileocecal barrier-related genes, and maintaining the integrity of the intestinal epithelium. Our data suggest that supplementation of feed with ALA may be an effective strategy to alleviate S. Typhimurium infection in chickens.

Gut Microbiota Disorder Contributes to the Production of IL-17A That Exerts Chemotaxis via Binding to IL-17RA in Endometriosis

Introduction

Endometriosis (EM) is a chronic estrogen-dependent condition characterized by the growth of endometrial-like tissue outside the uterus, posing a significant burden on reproductive-aged women. Previous research has shown a correlation between gut microbiota dysbiosis and interleukin-17A (IL-17A) in EM patients. IL-17A, a promising immunomodulatory molecule, exerts dual roles in human physiology, driving inflammatory diseases. However, the functions and origins of IL-17A in EM remain poorly characterized.

Methods

Single-cell data analysis was employed to characterize IL-17A activity in EM lesions. Fecal microbiota transplantation was conducted to explore the impact of gut microbiota on EM. Gut microbiota and bile acid metabolism were assessed via 16S rRNA sequencing and targeted metabolomics. Th17 cell proportions were measured using flow cytometry.

Results

High expression of IL-17 receptor A (IL-17RA) was observed in myeloid cell subpopulations within EM lesions and may be involved in the migration and recruitment of inflammatory cells in lesions. Elevated IL-17A levels were further validated in peritoneal and follicular fluids of EM patients. Dysregulated bile acid levels, particularly elevated chenodeoxycholic acid (CDCA) and ursodeoxycholic acid (UDCA), were found in the gut and peritoneal fluid of EM mouse models. Additional CDCA administration reduced EM lesions and modulated Th17 cell proportions, while UDCA showed no significant effects.

Discussion

Our findings shed light on the origins and functions of IL-17A in EM, implicating its involvement in lesion migration and recruitment. Dysregulated bile acid metabolism may contribute to EM pathogenesis, with CDCA exhibiting therapeutic potential.

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

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

Endometriosis, Pain, and Related Psychological Disorders: Unveiling the Interplay among the Microbiome, Inflammation, and Oxidative Stress as a Common Thread

Endometriosis (EM), a chronic condition in endometrial tissue outside the uterus, affects around 10% of reproductive-age women, significantly affecting fertility. Its prevalence remains elusive due to the surgical confirmation needed for diagnosis. Manifesting with a range of symptoms, including dysmenorrhea, dyschezia, dysuria, dyspareunia, fatigue, and gastrointestinal discomfort, EM significantly impairs quality of life due to severe chronic pelvic pain (CPP). Psychological manifestations, notably depression and anxiety, frequently accompany the physical symptoms, with CPP serving as a key mediator. Pain stems from endometrial lesions, involving oxidative stress, neuroinflammation, angiogenesis, and sensitization processes. Microbial dysbiosis appears to be crucial in the inflammatory mechanisms underlying EM and associated CPP, as well as psychological symptoms. In this scenario, dietary interventions and nutritional supplements could help manage EM symptoms by targeting inflammation, oxidative stress, and the microbiome. Our manuscript starts by delving into the complex relationship between EM pain and psychological comorbidities. It subsequently addresses the emerging roles of the microbiome, inflammation, and oxidative stress as common links among these abovementioned conditions. Furthermore, the review explores how dietary and nutritional interventions may influence the composition and function of the microbiome, reduce inflammation and oxidative stress, alleviate pain, and potentially affect EM-associated psychological disorders.

Integration of 16 S rRNA gene sequencing, metabonomics and metagenome analysis to investigate the mechanism of Sparganium stoloniferum-Curcuma phaeocaulis in treating of endometriosis in rats

BACKGROUND

Endometriosis is a gynecological disease that causes severe chronic pelvic pain and infertility in women. The therapeutic efficacy of the traditional herbal combination of Sparganium stoloniferum-Curcuma phaeocaulis (Sangleng-Ezhu, SL-EZ) in the treatment of endometriosis has been established. However, the precise mechanism by which this treatment exerts its effects remains elusive.

METHODS

To gain further insights, UPLC-MS/MS was employed to identify the primary chemical constituents of SL-EZ in serum. Additionally, network pharmacology was utilized to analyze the active ingredients and their corresponding targets. Furthermore, the impact of SL-EZ on ectopic endometrial growth in endometrial implants was assessed using a rat model. The therapeutic mechanism of SL-EZ in rats with endometriosis was further investigated through the application of 16 S rRNA gene sequencing, metagenomic sequencing, and metabolomics.

RESULTS

The primary compounds in serum were zederone, p-coumaric acid, dehydrocostus lactone, curdione, curcumol. The growth of ectopic lesions in a rat model was effectively inhibited by SL-EZ. In comparison to the control group, the endometriotic rats exhibited a decrease in α-diversity of the gut microbiota, an increase in the Firmicutes/Bacteroidetes ratio, and a reduction in the abundance of Ruminococcaceae. Following SL-EZ intervention, the potential probiotic strains Lactobacillus gasseri and Lactobacillus johnsonii were able to restore the intestinal microenvironment at the species level. The altered metabolites were significantly correlated with Verrucomicrobia, Proteobacteria, and Bacteroidetes. The metabolomic analysis demonstrated significant alterations in intestinal metabolites. And SL-EZ intervention also exerted regulatory effects on various metabolic pathways in gut microbiota, including aminoacyl-tRNA biosynthesis, monobactam biosynthesis, cyanoamino acid metabolism, glycine, serine and threonine metabolism, plant secondary metabolite biosynthesis, and amino acid biosynthesis.

CONCLUSION

The identification of novel treatment formulations for endometriosis was achieved through the utilization of network pharmacology and gut microbiota analyses. Our findings revealed simultaneous alterations in the microbiota within the rat model of endometriosis. The therapeutic efficacy of SL-EZ in treating endometriosis is attributed to its ability to restore the gut microbiota and regulate metabolism. This investigation offers valuable insights into the therapeutic mechanisms of traditional Chinese medicine (TCM) for endometriosis.

Role of the gut microbiota in the pathogenesis of endometriosis: a review

Endometriosis is classically defined as a chronic inflammatory heterogeneous disorder occurring in any part of the body, characterized by estrogen-driven periodic bleeding, proliferation, and fibrosis of ectopic endometrial glands and stroma outside the uterus. Endometriosis can take overwhelmingly serious damage to the structure and function of multi-organ, even impair whole-body systems, resulting in severe dysmenorrhea, chronic pelvic pain, infertility, fatigue and depression in 5-10% women of reproductive age. Precisely because of a huge deficiency of cognition about underlying etiology and complex pathogenesis of the debilitating disease, early diagnosis and treatment modalities with relatively minor side effects become bottlenecks in endometriosis. Thus, endometriosis warrants deeper exploration and expanded investigation in pathogenesis. The gut microbiota plays a significant role in chronic diseases in humans by acting as an important participant and regulator in the metabolism and immunity of the body. Increasingly, studies have shown that the gut microbiota is closely related to inflammation, estrogen metabolism, and immunity resulting in the development and progression of endometriosis. In this review, we discuss the diverse mechanisms of endometriosis closely related to the gut microbiota in order to provide new approaches for deeper exploration and expanded investigation for endometriosis on prevention, early diagnosis and treatment.

Alterations in gut and genital microbiota associated with gynecological diseases: a systematic review and meta-analysis

BACKGROUND

Increasing number of studies have demonstrated certain patterns of microbial changes in gynecological diseases; however, the interaction between them remains unclear. To evaluate the consistency or specificity across multiple studies on different gynecological diseases and microbial alterations at different sites of the body (gut and genital tract), we conducted a systematic review and meta-analysis.

METHODS

We searched PubMed, Embase, Web of Science, and Cochrane Library up to December 5, 2022(PROSPERO: CRD42023400205). Eligible studies focused on gynecological diseases in adult women, applied next-generation sequencing on microbiome, and reported outcomes including alpha or beta diversity or relative abundance. The random-effects model on standardized mean difference (SMD) was conducted using the inverse-variance method for alpha diversity indices.

RESULTS

Of 3327 unique articles, 87 eligible studies were included. Significant decreases were found in gut microbiome of patients versus controls (observed species SMD=-0.35; 95%CI, -0.62 to -0.09; Shannon index SMD=-0.23; 95%CI, -0.40 to -0.06), whereas significant increases were observed in vaginal microbiome (Chao1 SMD = 1.15; 95%CI, 0.74 to 1.56; Shannon index SMD = 0.51; 95%CI, 0.16 to 0.86). Most studies of different diagnostic categories showed no significant differences in beta diversity. Disease specificity was observed, but almost all the changes were only replicated in three studies, except for the increased Aerococcus in bacterial vaginosis (BV). Patients with major gynecological diseases shared the enrichment of Prevotella and depletion of Lactobacillus, and an overlap in microbes was implied between BV, cervical intraepithelial neoplasia, and cervical cancer.

CONCLUSIONS

These findings demonstrated an association between alterations in gut and genital microbiota and gynecological diseases. The most observed results were shared alterations across diseases rather than disease-specific alterations. Therefore, further investigation is required to identify specific biomarkers for diagnosis and treatment in the future.

Gut Microbiota and Endometriosis: Exploring the Relationship and Therapeutic Implications

Endometriosis is a common inflammatory disease affecting women of reproductive age, characterized by the growth of endometrial tissue beyond the uterus. In addition to gynecological manifestations, many endometriosis patients experience gastrointestinal symptoms, indicating a potential association between gut health and the disease. Recent studies have revealed alterations in the gut microbiota of individuals with endometriosis, including reduced diversity, microbial composition imbalances, and pathogenic bacteria. These changes can disrupt immune function, increase inflammation, and contribute to the chronic inflammatory state observed in endometriosis. Moreover, dysregulation of intestinal permeability may further exacerbate gastrointestinal symptoms in affected individuals. Understanding the role of the gut microbiota and intestinal permeability in endometriosis can provide valuable insights into disease pathogenesis, aid in non-invasive diagnostic approaches, and open new avenues for therapeutic interventions. Probiotics, in particular, have shown promise in improving endometriosis-associated pain symptoms and reducing endometriotic lesions in animal models. This review suggests that additional research and well-designed clinical trials are necessary to validate the potential diagnostic and therapeutic benefits of manipulating the gut microbiota in managing endometriosis and its gastrointestinal symptoms, thereby improving the quality of life for those affected.

Altered intestinal microbiota enhances adenoid hypertrophy by disrupting the immune balance

Introduction

Adenoid hypertrophy (AH) is a common upper respiratory disorder in children. Disturbances of gut microbiota have been implicated in AH. However, the interplay of alteration of gut microbiome and enlarged adenoids remains elusive.

Methods

119 AH children and 100 healthy controls were recruited, and microbiome profiling of fecal samples in participants was performed using 16S rRNA gene sequencing. Fecal microbiome transplantation (FMT) was conducted to verify the effects of gut microbiota on immune response in mice.

Results

In AH individuals, only a slight decrease of diversity in bacterial community was found, while significant changes of microbial composition were observed between these two groups. Compared with HCs, decreased abundances of Akkermansia, Oscillospiraceae and Eubacterium coprostanoligenes genera and increased abundances of Bacteroides, Faecalibacterium, Ruminococcus gnavus genera were revealed in AH patients. The abundance of Bacteroides remained stable with age in AH children. Notably, a microbial marker panel of 8 OTUs were identified, which discriminated AH from HC individuals with an area under the curve (AUC) of 0.9851 in the discovery set, and verified in the geographically different validation set, achieving an AUC of 0.9782. Furthermore, transfer of mice with fecal microbiota from AH patients dramatically reduced the proportion of Treg subsets within peripheral blood and nasal-associated lymphoid tissue (NALT) and promoted the expansion of Th2 cells in NALT.

Conclusion

These findings highlight the effect of the altered gut microbiota in the AH pathogenesis.

Current Updates on the Role of Microbiome in Endometriosis: A Narrative Review

Endometriosis affects approximately 6 to 10% of reproductive-age women globally. Despite much effort invested, the pathogenesis that promotes the development, as well as the progression of this chronic inflammatory disease, is poorly understood. The imbalance in the microbiome or dysbiosis has been implicated in a variety of human diseases, especially the gut microbiome. In the case of endometriosis, emerging evidence suggests that there may be urogenital-gastrointestinal crosstalk that leads to the development of endometriosis. Researchers may now exploit important information from microbiome studies to design endometriosis treatment strategies and disease biomarkers with the use of advanced molecular technologies and increased computational capacity. Future studies into the functional profile of the microbiome would greatly assist in the development of microbiome-based therapies to alleviate endometriosis symptoms and improve the quality of life of women suffering from endometriosis.

The gut microbiota and endometriosis: From pathogenesis to diagnosis and treatment

Endometriosis is a common gynecological disease, that often leads to pain and infertility. At present, the specific pathogenesis of endometriosis has not been clarified, but it may be closely related to an imbalance of sex hormones in the body, ectopic hyperplasia stimulated by immune inflammation, and invasion and escape based on tumor characteristics. Gut microbiota is associated with many inflammatory diseases. With the further study of the gut microbiota, people are paying increasing attention to its relationship with endometriosis. Studies have shown that there is an association between the gut microbiota and endometriosis. The specific ways and mechanisms by which the gut microbiota participates in endometriosis may involve estrogen, immune inflammation, and tumor characteristics, among others. Therefore, in the future, regulating gut microbiota disorders in various ways can help in the treatment of endometriosis patients. This study reviewed the research on the gut microbiota and endometriosis in order to provide ideas for clinical diagnosis and treatment.

Huayu Jiedu Fang Protects Ovarian Function in Mouse with Endometriosis Iron Overload by Inhibiting Ferroptosis

Endometriosis (EM) is a common chronic inflammatory disease in women. Sampson's retrograde menstruation theory is the most widely accepted theory of EM pathogenesis. The periodic bleeding of ectopic lesions is an important pathological feature of this disease, and the occurrence and progression of EM are closely associated with the iron overload caused by ectopic lesions. However, animal models that simulate menstrual-blood reflux and hemorrhage from EM lesions are lacking. In this study, we performed intraperitoneal injection of endometrial fragments and periodic intraperitoneal blood injection to simulate the real cause and disease state of EM and successfully constructed a mouse model of EM iron overload. Our research found that the number, size, and degree of adhesion of EM lesions in the iron-overload model mouse were significantly higher than those in the model mouse. Moreover, the iron concentration in the abdominal fluid and ovary significantly increased, and the level of malondialdehyde (MDA) in the ovary increased. Conversely, GPX4, GSH, and other anti-ferroptosis-related proteins were downregulated, proving the occurrence of ferroptosis. Huayu Jiedu Fang (HYJDF) is an empirical prescription for EM treatment. This study combined animal experiments, UHPLC-QE-MS analysis, and network pharmacology to analyze whether HYJDF can inhibit ferroptosis to slow down the progression of EM and protect ovarian function. Based on the constructed iron-overload model, HYJDF can reduce the volume of EM lesions and the degree of adhesion, downregulate the total iron concentration in the peritoneal fluid and ovary, upregulate GPX4 expression and GSSG in the ovary, downregulate the level of MDA in the ovary, and promote the development of follicles. We further confirmed that HYJDF can inhibit the progression of EM disease and improve the ovarian function of the model mouse by inhibiting ferroptosis. Finally, through UHPLC-QE-MS and network pharmacology analysis, the natural compounds in HYJDF were identified and verified and the regulatory effect of HYJDF on the EM ferroptosis pathway through the IL-6/hepcidin pathway was preliminarily elucidated.

Influence of the gut microbiota on endometriosis: Potential role of chenodeoxycholic acid and its derivatives

The gut microbiota (GM) has received extensive attention in recent years, and its key role in the establishment and maintenance of health and in the development of diseases has been confirmed. A strong correlation between the GM and the progression of endometriosis (EMS) has been observed in emerging research. Alterations in the composition and function of the GM have been described in many studies on EMS. In contrast, the GM in the environment of EMS, especially the GM metabolites, such as bile acids and short-chain fatty acids that are related to the pathogenesis of EMS, can promote disease progression. Chenodeoxycholic acid (CDCA), as one of the primary bile acids produced in the liver, is metabolized by various enzymes derived from the GM and is critically important in maintaining intestinal homeostasis and regulating lipid and carbohydrate metabolism and innate immunity. Given that the complexity of CDCA as a signalling molecule and the interaction between the GM and EMS have not been clarified, the role of the CDCA and GM in EMS should be understood from a novel perspective. However, few articles on the relationship between CDCA and EMS have been reviewed. Therefore, we review the available and possible potential links between CDCA, the GM and EMS and put forward the hypothesis that CDCA and its derivative obeticholic acid can improve the symptoms of EMS through the GM.

The Gut Microbiota: A Double Edge Sword in Endometriosis

Endometriosis that afflicts 1 in 10 women of reproductive age is characterized by growth of endometrial tissue in the extra-uterine sites and encompasses metabolic-, immunologic- and endocrine-disruption. Importantly, several comorbidities are associated with endometriosis, especially autoimmune disorders such as inflammatory bowel disease. Primarily thought of as a condition arising from retrograde menstruation, emerging evidence uncovered a functional link between the gut microbiota and endometriosis. Specifically, recent findings revealed altered gut microbiota profiles in endometriosis and in turn this altered microbiota appears to be causal in the disease progression, implying a bi-directional crosstalk. In this review, we discuss the complex etiology and pathogenesis of endometriosis emphasizing on this recently recognized role of gut microbiome. We review the gut microbiome structure and functions and its complex network of interactions with the host for maintenance of homeostasis that is crucial for disease prevention. We highlight the underlying mechanisms on how some bacteria promotes disease progression and others protects against endometriosis. Further, we highlight the areas that require future emphases in the gut microbiome-endometriosis nexus and the potential microbiome-based therapies for amelioration of endometriosis.