The role of the microbiome in exacerbations of chronic lung diseases

Abstract

Summary Culture-independent microbiological techniques have revealed a previously unappreciated complexity to the bacterial microbiome of the respiratory tract, forcing reconsideration of the interactions between host, bacteria and the pathogenesis of exacerbations of chronic lung disease. The composition of the lung microbiome is determined by microbial immigration, elimination, and the relative growth rates of its members; all of these change dramatically in chronic lung disease and further during exacerbations. Exacerbations lack key features of bacterial infections, including increased bacterial burden and decreased community diversity. We propose instead that exacerbations are occasions of respiratory dysbiosis: a disordered respiratory microbial ecosystem with negative effects on host biology. Respiratory dysbiosis provokes a dysregulated host immune response, which in turn alters microbial growth conditions in patient airways, further promoting dysbiosis and perpetuating a coupled cycle of inflammation and disordered microbiota. Differences in baseline respiratory microbiota may help explain the “frequent-exacerbator” phenotype observed across multiple disease states, and may provide novel targets for therapeutic intervention.

Lung microbiome dynamics in COPD exacerbations

“…Potentially, these pathogens could also indirectly trigger the excessive production of CXCL8/IL-8 through dysbiosis of the lung microbiota. Therefore, we speculate that the lung microbiome could serve as an additional line of defence that shapes the lung inflammatory response induced by respiratory pathogens [27].…”

“…Overgrowth of these bacterial OTUs could thus : not significantly associated with L2 β diversity, but present in its model. *: p<0.05; **: p<0.01; ***: p<0.001. drive respiratory tract dysbiosis, which has been suggested to be a potential cause of lung disease exacerbations [27]. Recent studies have highlighted the importance of ecological interactions in multiple human body habitats.…”

Human microbiome in respiratory diseases

“…Several studies that the lower airways and alveoli of patients with different lung diseases contain a microbiome different from that of healthy people and those changes in it are associated with the progression of the disease and the intermittent development of exacerbations (3).…”

Upper Respiratory Dysbiosis in Children

“…В то же время исследования пациентов раннего воз-раста с респираторной патологией выявили у них изменения микробиома верхних дыхатель-ных путей по отношению к здоровым детям [3]. Robert P. Dickson (2014) указывает на взаимос-вязь между дисбиозом и пролонгированным воспалением в респираторном тракте, обозна-чив это состояние как «Dysbiosis-Inflammation Cycle» [4]. Пролонгированное воспаление на слизистой оболочке верхних дыхательных пу-тей и в миндалинах лимфоидного глоточно-го кольца способствует их гипертрофии и ги-перплазии [4,5,6].…”

“…Robert P. Dickson (2014) указывает на взаимос-вязь между дисбиозом и пролонгированным воспалением в респираторном тракте, обозна-чив это состояние как «Dysbiosis-Inflammation Cycle» [4]. Пролонгированное воспаление на слизистой оболочке верхних дыхательных пу-тей и в миндалинах лимфоидного глоточно-го кольца способствует их гипертрофии и ги-перплазии [4,5,6]. Нозологическими форма-ми у детей, в патогенезе которых имеет место Dysbiosis-Inflammation Cycle, являются хрони-ческий ринит, аденоидные вегетации, гипер-трофия небных миндалин, хронический тон-зиллофарингит, бронхиальная астма, бронхоэк-татическая болезнь [3].…”