The Composition of Dental Plaque in Patients with Pulmonary Hypertension

ABSTRACT Background The oral microbiota significantly influences systemic health and is linked to various oral and systemic diseases. Dental plaque, a complex biofilm harboring diverse microorganisms, acts as an essential reservoir for the lung microbiome. Pulmonary hypertension (PH), a progressive pulmonary vascular disorder, remains poorly understood in terms of its association with oral microbiota. Methods This study defined and compared oral microbiota composition in dental plaque between PH patients (PH = 46) and reference subjects (HC = 34). A total of 80 dental plaque and 80 pharyngeal swab samples were analyzed by sequencing the 16S rRNA V3‐V4 region to assess oral and respiratory microbiome. Another 23 participants (PH = 15, HC = 8) were enrolled. Dental plaque samples were collected from them solely to perform RT‐qPCR as an independent validation. Results Oral microbiome health index (Oral MHI) is markedly lower in patients with PH, compared to those of the reference subjects. The microbial profiles on dental plaque showed significant differences between the two groups by principal component analysis. Linear discriminant analysis effect size also revealed significantly higher proportions of Prevotella and Veillonella in PH patients than reference subjects, which was also confirmed in another independent cohort by using RT‐qPCR. The microbial dysbiosis index (MDI) was significantly higher for PH patients compared with the controls both in the oral and pharyngeal regions. Our β‐diversity assessment and Procrustes tests confirmed a significant ecological disparity between the oral and pharyngeal regions. Conclusions Our study provides a comprehensive characterization of the distinct dental plaque microbiota between PH patients and control subjects. The dental plaque ecology of patients with PH is dysregulated, lowering Oral MHI. Their oral‐pharyngeal microbial communities correlate more strongly than those of healthy individuals. This weakened ecological divergence may increase PH patients' vulnerability to external pathogen colonization.