The respiratory microbiome: an underappreciated player in the human response to inhaled pollutants?

Purpose: Microbial communities in or on the body (i.e., the microbiome) are highly physiologically active and influence human health. Although environmental scientists are increasingly aware of the gut micro biome, the respiratory microbiome's role in the human response to inhaled pollutants is largely unknown. Methods: We reviewed the literature and present mechanisms by which the microbiome might mediate or modify human responses to inhaled pollutants. Results: The respiratory microbiome has been shown to influence chronic lung disease exacerbations, and increasing evidence indicates a role in disease development. Research also suggests that the respiratory microbiome could plausibly metabolize inhaled pollutants or modulate host inflammatory responses to exposure. Because these responses depend on the microbes present, defining the composition of the resident microbiome and how microbial communities shift with exposure may help to explain variations in susceptibility to inhaled pollutants. Although more research is needed, significant measurement challenges remain for large epidemiologic studies of the respiratory microbiome. Conclusions: The respiratory microbiome is likely an underexplored intermediate and potential cause of individual susceptibility to inhaled irritants/toxicants. Characterizing the microbiome's role in the human response to inhaled exposures could improve our understanding of the casual agents of exposure and suggest novel public health interventions. (C) 2016 Elsevier Inc. All rights reserved.