Gut microbiota and FHA - EC v.1

The aim of our study was to assess the gut microbiota composition in patients with FHA, compare it with that of a healthy population, and evaluate the effects of hormonal replacement therapy (HRT) on it. No statistical difference was found comparing the gut microbiota alpha diversity of FHA patients at baseline and post treatment. Also the overall gut microbial composition after HRT was similar to baseline. On the contrary, the relative abundance analysis revealed specific changes after HRT. At the phylum level, Fusobacteria were significantly increased after HRT, as well as Ruminococcus and Eubacterium genera.
To identify the main factors having an impact on the gut microbiota components that showed a significant variation after HRT, we conducted a multiple linear regression where the main hormonal parameters, inflammatory variables and endometrial thickness were included. Fusobacteria, which were increased after HRT in FHA, were correlated with the reduction in some proinflammatory cytokines (i.e., IL1ra, IL4, GCSF, and CCL2; Supplemental Table S1). The increase in [Ruminococcus] gnavus group post-therapy was associated with changes in endometrial thickness, and several hormonal and cytokine mediators (Supplemental Table S2). Finally, some hormonal variables and endometrial thickness, rather than inflammatory parameters, were the most relevant associated factors with the variations of [Eubacterium] hallii group (Supplemental Table S3).