A cross-sectional study of salivary and gut microbiomes in hemodialysis patients with heart failure with preserved ejection fraction

Background: Heart failure (HF) is a primary cause of death in patients on maintenance hemodialysis (MHD), yet the role of microbial dysbiosis is poorly defined. This study characterized the salivary and gut microbiomes of MHD patients with heart failure with preserved ejection fraction (HFpEF), those without HF (NHF), and healthy controls (CON). Methods: In this cross-sectional study (n=88), we compared the salivary and fecal microbiomes of HFpEF (n=30), NHF (n=30), and CON (n=28) groups using 16S rRNA gene sequencing. Microbial community structure and composition were analyzed. Results: Alpha diversity and Beta diversity analysis revealed a distinct salivary microbial structure, which effectively distinguished the MHD group from the Con group (P < 0.05). Conversely, the overall gut community structure showed no significant separation. At the genus level, both MHD groups showed depletion of salivary Veillonella and gut Faecalibacterium compared to controls. Notably, LEfSe analysis highlighted salivary Anaerocolumna as a promising candidate feature associated with the HFpEF group. Conclusion: Our analyses suggest that HFpEF in MHD patients may be associated with structural alterations in the oral microbiome, which appear more pronounced than those in the gut. Specific oral microbial signatures, particularly the enrichment of Anaerocolumna, showed associations with the HFpEF cohort in our study. This preliminary evidence positions the oral microbiome as an area worthy of further investigation for its potential role in this high-risk population.