Deciphering the Pain-Related Gut Microbiome in Patients With Endometriosis

Background: Endometriosis (EMS), which affects >10% of women, is characterized by painful symptoms, such as dysmenorrhea. Meanwhile, the gut microbiota is linked to EMS; however, the relationship between the gut microbiota and EMS-related pain remains unclear. Methods: This study conducted 16S rRNA sequencing on fecal samples from 20 patients with EMS and dysmenorrhea, 13 patients with EMS but not dysmenorrhea, and 12 healthy controls. Results: Carbohydrate antigen 125 (CA125) levels were significantly higher in patients with EMS and dysmenorrhea. No significant differences in α- and β-diversity values were observed among the three groups (p > 0.05). However, Proteobacteria and Subdoligranulum showed increased abundance trends in patients with EMS and dysmenorrhea. Acinetobacter and Colidextribacter were less abundant in patients with EMS and dysmenorrhea than in those without dysmenorrhea (p < 0.05). Faecalicoccus pleomorphus and its genus also showed consistent depletion. At the genus level, a correlation analysis of the differential microbes revealed that UCG_005 and UCG_002 were central nodes in the correlation network (p < 0.05). Functional prediction indicated significant enrichment in cofactor and vitamin metabolism pathways in the EMS group with dysmenorrhea (p < 0.05). Several differential microbes, such as Faecalicoccus, Colidextribacter, and Acinetobacter, were negatively correlated with pain severity. Receiver operating characteristic curve analysis identified 10 microbial species with moderate diagnostic potential (area under the curve >0.7) for discriminating patients with EMS and dysmenorrhea, notably Ligilactobacillus. Conclusions: These results highlight distinct microbial alterations and functional pathways associated with EMS-related pain, suggesting potential diagnostic biomarkers for this condition.