Impact of 6-Month Exposure to Aerosols from Potential Modified Risk Tobacco Products Relative to Cigarette Smoke on the Rodent Gastrointestinal Tract

The impact of two candidate modified risk tobacco products (CMRTP) relative to cigarette smoke (CS), as well as the effect of cessation or switching to a CMRTP, was investigated in a 6-month APOE mouse exposure study. The cardiovascular disease end point data have already been published, and here we present the findings on the gut-related endpoints. We used an extensive shotgun microbiome DNA sequencing approach to perform taxonomic profiling of digesta and excreta, as well as host RNA sequencing to characterize the transcriptional effects on the cecum. The effects in CS exposed mice relative to control mice included significant gene dysregulation and an increase in the abundance of mucus-related bacteria. The key taxonomic changes are reversed upon cessation. Switching to a CMRTP exposure caused an increase in the Lactobacillaceae. This is one of very few studies investigating changes to the mouse gut microbiome in response to long-term smoke and aerosol exposure.