Exploring the link between airway microbiota and coronary heart disease in COPD patients and controls

Background: Chronic obstructive pulmonary disease (COPD) and coronary
heart disease (CHD) are major causes of morbidity and mortality, with
shared risk factors and often co-occurring. This study investigated the
association between both the upper and lower airway microbiome and CHD in
healthy controls and COPD patients. Methods: 228 participants from the
MicroCOPD study (101 controls and 127 COPD patients) underwent coronary CT
angiography to assess calcium score (CaSc) and coronary stenosis. Oral
wash (OW) and bronchoalveolar lavage (BAL) samples were collected.
Microbial DNA was analyzed using 16S rRNA gene sequencing with the
Illumina MiSeq platform. Microbiome composition and diversity were
analyzed using established pipelines in Quantitative Insights into
Microbial Ecology 2 (QIIME 2) and R. Results: Firmicutes dominated across
all subgroups, followed by Bacteroidetes and Actinobacteria. Several taxa
were found to be differentially abundant between CHD and non-CHD groups
but comprised less than 1% of all taxa. Alpha diversity (Shannon index)
differed significantly between COPD patients and controls in OW
(p<0.01), but not BAL. No statistically significant alpha (Shannon
or Faith’s PD) diversity differences were found between CHD and non-CHD
groups. Beta diversity analysis (Bray-Curtis dissimilarity) revealed no
significant differences in microbial composition between CHD and non-CHD
groups, both for COPD patients and controls (p>0.05). Conclusion:
The microbiome differed between COPD patients and controls, but we could
not find evidence that either the upper or lower airway microbiome
differed between those with and without coronary heart disease.