P-324 Finding on the gut microbiome impact on non-reproductive pathologies of the uterus: an endometriosis perspective
Authors: De Tena Sanz A , Martínez Lara A , Durán González E , Reyes Conde M  I , Díaz López C , Pérez Sánchez M , Ramírez Tejero J  A , Horcajadas Almansa J  A , Cotán D 
Published: July 2024

Abstract

Study question
Is there any link between intestinal microbiome and endometriosis?

Summary answer
The aetiopathogenesis of endometriosis might be linked to intestinal dysbiosis. Microorganisms could be used as potential microbiota-mediated metabolites therapy to target the estrobolome in endometriosis.

What is known already
Endometriosis (EMs) is a chronic estrogenic-dependent gynaecological condition with a complex and multifactorial aetiology, characterized by the presence of endometrial glands and endometrial-like tissue outside the uterus, accompanied by a severe inflammatory process. Sampson’s theory of retrograde menstruation is considered one of the most convincing hypotheses for the origin of EMs. Recently, the human microbiome has been linked to its pathogenesis, and exits some evidence that it might modulate the immune system from the gut, therefore the generation of a dysfunctional immune response caused by intestinal dysbiosis might play an important role in the initiation and progression of EMs.

Study design, size, duration
A case-control study was designed to analyse intestinal microbiome from EMs patients and age-matched healthy women. Herein, we aim to investigate for potential intestinal biomarkers related to the pathology. The recruitment was through health questionnaires such as EHP-5 setting the initial cohort at 243 women. This initial cohort was screened according to inclusion and exclusion criteria.

Participants/materials, setting, methods
Seventy-seven women met eligibility criteria and were enrolled in the study. Stool samples from the controls group (n = 43) and patients with a positive diagnosis of EMs (n = 34) were collected and subjected to 16S rRNA gene sequencing using the V3-V4 regions. Various multivariate analysis approaches were used to assess diversity, composition and abundance of intestinal microbiota.

Main results and the role of chance
The number of significantly different taxa between healthy controls and EMs patients were 18 (p-value&lt;0.05). Among these 18 taxa, we found 3 families: Bacteroidaceae, Lactobacillaceae and Desulfovibrionaceae; 3 genera: Blautia, Anaerostipes and Lachnospira; and 12 species: Roseburia intestinalis, Bacteroides uniformis, Anaerobutyricum hallii, among others), with a higher diversity of families and genera in the patient group, while the control group had a higher diversity of species, according to the results of Shannon and Simpsońs indexes. This suggests that EMs is dominated by a few species belonging to a wide variety of families and genera, while in the control group there is a greater variability of intestinal species belonging to a smaller number of families and genera. These taxa were related with molecular routes implied in the management of inflammation and estrogens signalling.
Additionally, the data were correlated with clinical parameters through the Endometriosis Health Profile-5 questionnaire (EHP-5). This correlation shows significant differences specifically into the «self-image» variable and the total score with the genus diversity (positive and negative correlations were reported), with a strong positive correlations between the variable “Infertility” and the genus Anaerostipes.

Limitations, reasons for caution
Pronacera develops molecular tests for several conditions that involve the analysis of genes, proteins, and microbes in human samples. Neither the patients nor the healthcare professionals participating in this study have been paid or influenced whatsoever. Hence, the authors report no other potential conflicts of interest.

Wider implications of the findings
The aetiopathogenesis of EMs might be linked to intestinal dysbiosis. In this sense, the taxa identified in this study and its estrobolome-related metabolite could play a key role in the initiation of the disease, proposing themselves as potential prognostic, diagnostic and therapeutic targets for the future.

Trial registration number
not applicable