Associations Between Endometriosis and Gut Microbiota Original paper

What Was Studied?

This study investigated the association between endometriosis and gut microbiota. Conducted at Skåne University Hospital in Sweden, the research aimed to understand how the gut microbiome differs in women diagnosed with endometriosis compared to healthy controls. The study included 66 women with endometriosis confirmed through laparoscopy or laparotomy and 198 age, BMI, and smoking-matched controls. Stool samples from both groups were analyzed using 16S ribosomal RNA sequencing to identify bacterial composition at the genus level. The primary objective was to compare the diversity and abundance of gut microbiota between the two groups and explore any microbiome changes correlated with endometriosis characteristics such as disease localization, gastrointestinal symptoms, or hormonal treatment.

Who Was Studied?

The study examined 66 women diagnosed with endometriosis recruited from the Department of Gynaecology at Skåne University Hospital. These participants were matched with 198 controls from the Malmö Offspring Study (MOS), ensuring similarities in age, BMI, and smoking status. Women in the endometriosis group were diagnosed based on clinical criteria, confirmed through surgical procedures, and were excluded if they had comorbid gastrointestinal conditions like Crohn’s disease, ulcerative colitis, or irritable bowel syndrome (IBS). The control group, drawn from a population-based cohort, also passed stool samples and completed questionnaires about their medical history and gastrointestinal symptoms.

What Were the Most Important Findings?

The study found significant differences in gut microbiota diversity and composition between women with endometriosis and healthy controls. Notably, alpha and beta diversities were higher in the control group, suggesting a richer and more varied microbial population compared to endometriosis patients. At the genus level, 12 bacterial genera belonging to the classes Bacteroidia, Clostridia, Coriobacteriia, Bacilli, and Gammaproteobacteria differed significantly between groups. For instance, Bacteroides and Parabacteroides were elevated in endometriosis patients, while Paraprevotella and Lachnospira were found in lower abundance compared to controls. Additionally, there was a distinct alteration in the microbial community within the endometriosis cohort based on disease localization and the presence of gastrointestinal symptoms. Patients with isolated ovarian endometriosis exhibited higher levels of Lachnobacterium and Adlercreutzia compared to those with widespread lesions. Furthermore, the presence of gastrointestinal symptoms correlated with lower levels of SMB53 (Clostridia) and Odoribacter (Bacteroidia), while Prevotella was more abundant. Interestingly, hormone treatment was associated with higher levels of Blautia and Ruminococcus in the Clostridia class, along with Butyricimonas in the Bacteroidia class. These findings support the hypothesis that gut microbiota may be altered in endometriosis patients, with distinct microbial signatures linked to hormonal therapy and gastrointestinal involvement.

What Are the Greatest Implications of This Study?

The study’s findings suggest that endometriosis is associated with specific alterations in gut microbiota, which could play a role in the pathophysiology of the disease. The reduced microbial diversity in endometriosis patients points towards a potential dysbiosis that may exacerbate inflammation and modulate estrogen metabolism, both of which are critical in the pathogenesis of endometriosis. Furthermore, specific bacterial shifts linked to hormone treatment indicate that gut microbiota could be influenced by estrogen-related therapies, potentially affecting symptom severity and disease progression. Understanding these microbial associations opens the door to novel therapeutic strategies, such as targeted probiotics or microbiome-based interventions, to alleviate gastrointestinal symptoms and modulate disease activity in endometriosis patients. This research also underlines the need for further studies to explore the bidirectional relationship between gut microbiota and estrogen regulation in estrogen-dependent conditions like endometriosis.