Exploring Microbial Signatures in Endometrial Tissues with Endometriosis

OBJECTIVE: The endometrial microbiota exerts a crucial role in maintaining the health of the female reproductive system. As such, in this study, we have examined the composition of the microbiota in endometrium tissues with and without endometriosis, with the objective of identifying key species that may potentially contribute to the progression of endometriosis. METHODS: We obtained endometrial tissues from 43 women diagnosed as either having endometriosis or not. Subsequently, we utilized a diverse array of techniques, including fluorescence in situ hybridization (FISH), immunohistochemistry (utilizing anti-LPS and anti-LTA antibodies), transmission electron microscopy (TEM), and 16S rRNA sequencing, to undertake a comprehensive examination of the presence of microorganisms in the endometrium and their potential role in endometriosis. RESULTS: Our findings consistently indicated the existence of bacteria in both normal endometrium tissues and those affected by endometriosis. By employing the fluorescent co-staining technique, we observed the colocalization of macrophages and bacteria in both tissue types. Notably, we discovered a significant increase in microbial diversity in endometrial tissue from women with endometriosis compared to normal endometrial tissues. Additionally, we identified 13 species that were more abundant in the normal group, such as Acinetobacter guillouiae. In contrast, seven species were prominent in the endometriosis group, with Faecalibacterium prausnitzii being a notable one. Finally, our results suggest that Faecalibacterium prausnitzii may play an essential role in the progression of endometriosis. CONCLUSION: We carried out a comprehensive analysis of the endometrial microbial landscape in endometriosis tissue and revealed that Faecalibacterium prausnitzii is a pivotal species that may potentially play a crucial role in the pathogenesis of endometriosis.