Human matters in asthma: Considering the microbiome in pulmonary health

Abstract

Graphical AbstractExogenous factors that influence the microbiome and asthma pathogenesis. External factors including a well-balanced diet and clean air support a healthy gut microbiome that releases metabolites and short-chain fatty acids (SCFA) that promote a healthy pulmonary immune system that remains non-inflammatory thereby protecting against the development of asthma or asthma exacerbations (left panel). An unhealthy diet, dirty air, and some pharmaceutical agents on the other hand can induce dysbiosis in the gut and lung microbial communities through induction of co-morbid states like obesity and aberrant immune activation. Additional confounders including modes of delivery and feeding, use of antibiotics during pregnancy and childhood also have an impact on the airway microbial homeostasis and asthma onset and pathogenesis (right panel). Figure prepared on BioRender.

The Impact of Smoking on Microbiota: A Narrative Review

“…Once the pathology is established, one of the most interesting findings about the asthmatic microbiota concerns the increase in Proteobacteria, such as Neisseria and Haemophilus spp., and the decrease of Bacteroidetes, such as Prevotella spp. [ 33 , 46 ]. Moreover, the microbiota—in particular Streptococcus pneumoniae , Haemophilus influenzae , Moraxella catarrhalis , Chlamydia pneumoniae , and Mycoplasma pneumoniae —is involved in the recurrence, severity, and response to therapy of exacerbations [ 46 ].…”

“…[ 33 , 46 ]. Moreover, the microbiota—in particular Streptococcus pneumoniae , Haemophilus influenzae , Moraxella catarrhalis , Chlamydia pneumoniae , and Mycoplasma pneumoniae —is involved in the recurrence, severity, and response to therapy of exacerbations [ 46 ].…”

Effects of early postnatal hyperoxia exposure combined with early ovalbumin sensitization on lung inflammation and bacterial flora in a juvenile mouse model of asthma

“…When mice were exposed to microorganisms, their pulmonary inflammatory responses were exacerbated; newborn animals tended to show a strong response to allergens, and regulatory T cells appeared as the bacterial load increased, and the response to allergens was subsequently attenuated ( Herbst et al, 2011 ; Gollwitzer et al, 2014 ). In an analysis of sputum and bronchoalveolar lavage fluid (BALF) samples collected from patients with severe asthma, the abundance of Proteobacteria, especially Haemophilus and Moraxella , was elevated in patients with neutrophilic asthma and was strongly associated with AHR and airway inflammation ( Taylor et al, 2017 ; Marathe et al, 2022 ), suggesting the role of the respiratory microbiome in asthma pathogenesis and control.…”