Oral microbiome between patients with non-obstructive and obstructive hypertrophic cardiomyopathy.

Background: The profile and clinical significance of the oral microbiome in patients with non-obstructive hypertrophic cardiomyopathy (noHCM) and obstructive hypertrophic cardiomyopathy (oHCM) remain unexplored. The objective of this study was to evaluate the difference of oral microbiome between noHCM and oHCM patients.

Methods: This cross-sectional study enrolled 18 noHCM patients and 26 oHCM patients from Fuwai Hospital, Chinese Academy of Medical Sciences between 2020 and 2021. Clinical and periodontal evaluations were conducted, and subgingival plaque samples were collected. Metagenomic sequencing and subsequent microbial composition and functional analyses were performed.

Results: Compared to oHCM patients, those with noHCM had higher systolic blood pressure (138.1 ± 18.8 mmHg vs. 124.2 ± 13.8 mmHg, P = 0.007), a larger body circumference (neck circumference: 39.2 ± 4.0 cm vs. 35.1 ± 3.7 cm, P = 0.001; waist circumference: 99.7 ± 10.5 cm vs. 92.2 ± 10.8 cm, P = 0.027; hip circumference: 102.5 ± 5.6 cm vs. 97.5 ± 9.1 cm, P = 0.030), a greater left ventricular end-diastolic diameter (46.6 ± 4.9 mm vs. 43.1 ± 4.9 mm, P = 0.026), and a lower left ventricular ejection fraction (64.1 ± 5.7 % vs. 68.5 ± 7.8%, P = 0.048). While overall biodiversity and general microbial composition were similar between the noHCM and oHCM groups, ten taxa displayed significant differences at the genus and species levels, with Porphyromonas gingivalis showing the highest abundance and greater enrichment in noHCM (relative abundance: 7.79535 vs. 4.87697, P = 0.043). Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis identified ten distinct pathways, with pathways related to energy and amino acid metabolism being enriched in oHCM patients, and those associated with genetic information processing less abundant in the oHCM group. Metabolic potential analysis revealed ten significantly altered metabolites primarily associated with amino sugar and nucleotide sugar metabolism, porphyrin metabolism, pentose and glucuronate interconversion, and lysine degradation.

Conclusions: The higher abundance of Porphyromonas gingivalis, which is known to impact cardiovascular health, in noHCM patients may partially account for clinical differences between the groups. Pathway enrichment and metabolic potential analyses suggest microbial functional shifts between noHCM and oHCM patients, potentially reflecting inherent metabolic changes in HCM.