Gut microbiota in patients undergoing hemodialysis and the effect of synbiotic therapy on its composition

Introduction. Growing evidence highlights the critical role of the gut microbiota in human health, homeostasis, and disease development and progression. The gut-kidney axis plays a pivotal role in mediating the interaction between the gut microbiota and renal function. Dysbiosis and progressive biochemical alterations within the intestinal milieu contribute to chronic inflammation and increased intestinal permeability. The systemic translocation of toxic microbial metabolites, particularly uremic toxins, may result in damage to multiple organ systems, including the kidneys.

Currently, data on the gut microbiota and its metabolites in patients undergoing hemodialysis, as well as on the effects of symbiotic therapy in this population, remains limited and often conflicting.

Methods. The prospective cohort study included 26 patients receiving standard, adequate hemodialysis three times weekly. Gut microbiota samples were collected and analysed at two time points: before initiation of symbiotic therapy, and after months of treatment. Microbial composition was assessed using 16S rRNA sequencing followed by bioinformatic analysis.

Results. Synbiotics therapy significantly affected the alpha and beta diversity of the gut microbiota in patients undergoing hemodialysis. Significant changes in alpha-diversity indices were observed following treatment, with decreases in both the Shannon and Chao1 indices. Analysis of beta diversity demonstrated a significant shift in microbial community composition after completion of symbiotic therapy. Specifically, the Bray-Curtis dissimilarity index revealed significant clustering of post-treatment samples. Although baseline microbiota profiles were relatively similar among patients, microbial community dispersion increased substantially following the intervention. Synbiotic therapy was associated with relative abundances of the families Lactobacillaceae and Veillonellaceae, whereas abundancies of the families Anaerovoracaceae and Acidaminococcaceae decreased. These changes were accompanied by reduction in the relative abundance of [Ruminococcus] gnavus, [Ruminococcus] gauvreauii, Phascolarctobacterium, and Sutterella.

Conclusion. The observed changes in the gut microbiota composition following symbiotic therapy are complex and difficult to interpret definitely. Nevertheless, we believe that synbiotics administration may promote favorable alternations in the interstinal microbial community. A comprehensive assessment of the clinical significance of these changes should incorporate analyses of circulating metabolites and patient outcomes. Further studies are needed to clarify the effects of synbiotics on the gut microbiota and their potential therapeutic implications in patients undergoing hemodialysis.

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