The diagnosis of endometriosis is typically delayed by years for the unexclusive symptom and the traumatic diagnostic method. Several studies have demonstrated that gut microbiota and cervical mucus potentially can be used as auxiliary diagnostic biomarkers. However, none of the previous studies has compared the robustness of endometriosis classifiers based on microbiota of different body sites or demonstrated the correlation among microbiota of gut, cervical mucus, and peritoneal fluid of endometriosis, searching for alternative diagnostic approaches. Herein, we enrolled 41 women (control, n = 20; endometriosis, n = 21) and collected 122 well-matched samples, derived from feces, cervical mucus, and peritoneal fluid, to explore the nature of microbiome of endometriosis patients. Our results indicated that microbial composition is remarkably distinguished between three body sites, with 19 overlapped taxa. Moreover, endometriosis patients harbor distinct microbial communities versus control group especially in feces and peritoneal fluid, with increased abundance of pathogens in peritoneal fluid and depletion of protective microbes in feces. Particularly, genera of Ruminococcus and Pseudomonas were identified as potential biomarkers in gut and peritoneal fluid, respectively. Furthermore, novel endometriosis classifiers were constructed based on taxa selected by a robust machine learning method. These results demonstrated that gut microbiota exceeds cervical microbiota in diagnosing endometriosis. Collectively, this study reveals important insights into the microbial profiling in different body sites of endometriosis, which warrant future exploration into the role of microbiota in endometriosis and highlighted values on gut microbiota in early diagnosis of endometriosis.

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.

Background: miRNA expression profiles in ectopic endometrium (EC) serving as pathophysiologic genetic fingerprints contribute to determining endometriosis progression; however, the underlying molecular mechanisms remain unknown. Methods: miRNA microarray analysis was used to determine the expression profiling of EC fresh tissues. qRT-PCR was performed to screen miR-205-5p expression in EC tissues. The roles of miR-205-5p and its candidate target gene, angiopoietin-2 (ANGPT2), in endometriosis progression were confirmed on the basis of both in vitro and in vivo systems. miR-205-5p and ANGPT2 expression were measured by in situ hybridization and immunochemistry, and their clinical significance was statistically analysed. Results: miR-205-5p was screened as a novel suppressor of endometriosis through primary ectopic endometrial stromal cell migration, invasion, and apoptosis assay in vitro, along with endometrial-like xenograft growth and apoptosis in vivo. In addition, ANGPT2 was identified as a direct target of miR-205-5p through bioinformatic target prediction and luciferase reporter assay. Re-expression and knockdown of ANGPT2 could respectively rescue and simulate the effects induced by miR-205-5p. Importantly, the miR-205-5p-ANGPT2 axis was found to activate the ERK/AKT pathway in endometriosis. Finally, miR-205-5p and ANGPT2 expression were closely correlated with the endometriosis severity. Conclusion: The newly identified miR-205-5p-ANGPT2-AKT/ERK axis illustrates the molecular mechanism of endometriosis progression and may represent a novel diagnostic biomarker and therapeutic target for disease treatment.

Endometriosis is a chronic inflammatory gynecological disease. Previous studies have explored relationships between endometriosis and the microbiota, but none have focused on differences in gut microbiota between early-stage and late-stage endometriosis patients or their connections to dysmenorrhea symptoms. This study compared gut microbiota compositions between early-stage and late-stage endometriosis patients using amplicon sequencing and further analyzed their dysmenorrhea symptoms. To minimize seasonal and dietary impacts, we recruited Guangdong residents hospitalized for surgery at Zhujiang Hospital. Participants underwent preoperative screening based on enrollment criteria and fecal samples were collected. Endometriosis was classified according to the American Society for Reproductive Medicine (ASRM) staging system based on surgincal and pathological findings. Stage I-II cases were designated as early-stage endometriosis, and Stage III-IV as late-stage endometriosis. A total of 112 patient fecal samples were collected, with 75 (median age, 32 years [range, 18–49 years]) meeting the enrollment criteria, including 39 early-stage (32 Stage I and 7 Stage II) and 36 late-stage (16 Stage III and 20 Stage IV) patients. The gut microbiota structure and functions in early-stage patients significantly differed from those in late-stage cases. Dysmenorrhea was associated with specific microbial traits. Late-stage patients with dysmenorrhea displayed distinctly different gut profiles compared to other endometriosis groups. Bartonella, Snodgrassella, and other taxa were enriched in late-stage cases, while Bacteroides, and Prevotella were decreased. The gut microbial community structure in early-stage endometriosis patients significantly differs from that in late-stage cases, with late-stage patients experiencing dysmenorrhea displaying particularly distinct gut profiles. Predicted functional analysis indicated suppressed steroid biosynthesis pathways in the gut of late-stage endometriosis patients. In conclusion, it is plausible that the multiple effects of steroids on the lower gastrointestinal tract may involve microbiota alterations, suggesting the need for further investigations.

Endometrial-derived stem cells (EnSCs) serve an important role in the development of endometriosis via retrograde menstruation. Abnormal expression of miRNAs in EnSCs is involved in the etiology of endometriosis, however, the mechanisms remain unclear. The aim of the present study was to investigate the expression of miR‑34a‑5p and VEGFA in endometrial samples from patients with or without endometriosis, and then examine the underlying mechanism of microRNA‑34a‑5p regulation of VEGFA in EnSCs. Endometrial samples from patients with or without endometriosis were collected, and miR‑34a‑5p expression in the two groups was measured using RT‑PCR. Human endometrial‑derived stem cells (hEnSCs) were isolated from these endometrial samples, and hEnSCs were transfected with the miR‑34a‑5p mimics or control miRNAs. qPCR and western blotting were performed to assess the effects of miR‑34a‑5p on the expression of VEGFA in hEnSCs, and cell growth was assessed by an MTT assay. miR‑34a‑5p was significantly downregulated in patients with endometriosis when compared with that of those without endometriosis. VEGFA expression levels in hEnSCs with an overexpression of miR‑34a‑5p were significantly reduced when compared with those in the negative control (P<0.01). In addition, the upregulation of miR‑34a‑5p suppressed EnSCs proliferation by targeting the 3' untranslated region of VEGFA. miR‑34a‑5p provides a novel avenue for the understanding of the development of endometriosis, and may facilitate the development of potential therapeutics against endometriosis.

In this longitudinal cohort study, our results demonstrated that there are rhythmic changes in gut microbial network signatures in early life, and healthy infants adopt more complex and stable network structure in their gut microbiota than that of the infants with eczema.