# Gut microbiota composition and systemic immune-inflammatory marker correlations in infertile women with endometriosis: a pilot case–control study

## TL;DR

This study explores gut microbiota differences in infertile women with endometriosis and finds links to immune markers, suggesting a possible role of gut bacteria in infertility.

## Contribution

The study identifies specific gut microbial signatures and their correlations with immune-inflammatory markers in endometriosis-related infertility.

## Key findings

- Endometriosis group showed enriched Lachnospira, Bacilli, Lactobacillales, and other bacterial taxa.
- Streptococcus and Veillonella correlated with macrophage migration inhibitory factor (MIF), while Bilophila and Enterococcus correlated with TNF-α and IL-6.
- Desulfovibrionaceae was negatively correlated with TNF-α and IL-6, and Parasutterella with CA125.

## Abstract

The specific gut microbial signatures and their correlation with immune-inflammatory markers in infertile women with endometriosis remain underexplored.To investigate the differences in gut microbiota and their associations with biochemical immune markers in infertile women with endometriosis compared to controls.

This case-control study enrolled 32 infertile women with endometriosis and 13 control women with male-factor infertility. Fecal samples were collected for 16S rRNA sequencing to profile the gut microbiota, and serum samples were obtained to measure inflammation-related biomarkers. Bioinformatics analyses were applied to compare gut microbial community structures and to examine correlations between differentially abundant bacteria and immune markers.

The endometriosis group exhibited significant enrichment of Lachnospira, Bacilli, Lactobacillales, Parasutterella, Enterococcus, and Veillonella. Comparative analysis revealed significantly altered abundances of multiple taxa, including Lachnospira, Parasutterella, Alistipes, Enterococcus, Veillonella, Streptococcus, Desulfovibrionaceae, Ruminococcaceae, Bilophila, and Peptoniphilus (all P < 0.05). Several inter-species correlations were identified among these bacteria. Importantly, specific microbiota were correlated with immune markers: Streptococcus and Veillonella were positively correlated with macrophage migration inhibitory factor (MIF); Bilophila and Enterococcus were positively correlated with TNF-α and IL-6; Veillonella was positively correlated with TNF-α; Desulfovibrionaceae was negatively correlated with TNF-α and IL-6; and Parasutterella was negatively correlated with CA125.

In this exploratory investigation, specific gut microbial signatures were observed in infertile patients with endometriosis, showing correlations with select systemic immune-inflammatory biomarkers. These initial observations point to a possible association between gut microbiota imbalance and the inflammatory aspects of endometriosis-associated infertility. Consequently, microbial modulation merits further investigation as a potential strategy to alleviate inflammation and potentially enhance reproductive outcomes.