Saliva as a non-invasive specimen for COPD assessment

Area of Science:

• Microbiology
• Pulmonary Medicine
• Genomics

Background:

• Chronic Obstructive Pulmonary Disease (COPD) is associated with distinct airway microbiota.
• Current methods for airway microbiota analysis, like bronchoalveolar lavage (BAL) and sputum collection, are invasive and resource-intensive.
• Non-invasive upper airway samples, such as saliva, are underexplored for their potential in COPD research.

Purpose of the Study:

• To identify the characteristic oral bacterial profile in patients with COPD.
• To investigate the association between salivary bacterial composition and COPD.
• To assess the utility of saliva as a non-invasive biomarker for COPD.

Main Methods:

• Recruitment of outpatients with COPD and age-sex matched healthy controls.
• 16S rRNA profiling to characterize oral bacteria composition.
• Clustering analysis of oral bacteria beta-diversity and logistic regressions to evaluate associations with COPD.

Main Results:

• Differential abundance analysis revealed increased Proteobacteria (especially Haemophilus) and reduced microbial diversity in COPD patients, mirroring lower airway findings.
• Unsupervised clustering identified two patient groups based on microbiota composition, differing in hospitalization rates for severe acute exacerbations of COPD (AECOPD) and GOLD D classification.
• A low abundance of Prevotella was significantly associated with a higher risk of recent severe AECOPD and GOLD D status.

Conclusions:

• Salivary bacteria composition is associated with COPD, particularly with severe exacerbations.
• Saliva serves as a viable non-invasive specimen for future research on heterogeneous respiratory diseases like COPD.
• Oral microbiota profiling in saliva may aid in understanding COPD heterogeneity and predicting exacerbation risk.