Objectives: Chronic lung diseases (CLD) have been linked with alterations of bacterial microbial communities in the lungs. However, the detailed molecular influence of cigarette smoke (CS) as the major risk factor for CLD on the lung microbiome has not been understood so far. Thus, we aim to investigate longitudinal changes of the lung microbiome upon CS exposure. Methods: 7-week-old Balb/c mice were exposed to air or 4 puffs/min mainstream CS generated from 3R4F research cigarettes (University of Kentucky, USA) 1h/day, 5 days/week using a commercial smoking robot (SCIREQ, Canada). Total particulate matter (mean 7.12 mg/m3) was quantified by photometric measurement (MicroDust Pro, Casella UK). After 7, 21 and 56 days of exposure, lungs, caecum and bronchoalveolar lavage fluid (BALF) were collected for 16S rRNA gene sequencing and quantification of inflammatory cells. Results: Body weights were notably lower (p Conclusion: Mainstream CS exposure alters the gut microbial composition after 56 days of exposure. The bacterial communities in the lung were also affected, but to a lower extent. In a next step we will evaluate if and how fast the microbiota can regenerate after smoking cessation.
