Blood and urine multi-omics analysis of the impact of e-vaping, smoking, and cessation: from exposome to molecular responses.

Cigarette smoking is a major preventable cause of morbidity and mortality. While quitting smoking is the best option, switching from cigarettes to non-combustible alternatives (NCAs) such as e-vapor products is a viable harm reduction approach for smokers who would otherwise continue to smoke. A key challenge for the clinical assessment of NCAs is that self-reported product use can be unreliable, compromising the proper evaluation of their risk reduction potential. In this cross-sectional study of 205 healthy volunteers, we combined comprehensive exposure characterization with in-depth multi-omics profiling to compare effects across four study groups: cigarette smokers (CS), e-vapor users (EV), former smokers (FS), and never smokers (NS). Multi-omics analyses included metabolomics, transcriptomics, DNA methylomics, proteomics, and lipidomics. Comparison of the molecular effects between CS and NS recapitulated several previous observations, such as increased inflammatory markers in CS. Generally, FS and EV demonstrated intermediate molecular effects between the NS and CS groups. Stratification of the FS and EV by combustion exposure markers suggested that this position on the spectrum between CS and NS was partially driven by non-compliance/dual use. Overall, this study highlights the importance of in-depth exposure characterization before biological effect characterization for any NCA assessment study.

Assessment of in vitro kinetics and biological impact of nebulized trehalose on human bronchial epithelium.

Trehalose is added in drug formulations to act as fillers or improve aerosolization performance. Its characteristics as a carrier molecule have been explored; however, the fate of trehalose in human airway tissues has not been thoroughly investigated. Here, we investigated the fate of nebulized trehalose using in vitro human air-liquid bronchial epithelial cultures. First, a tracing experiment was conducted using 13C12-trehalose; we measured trehalose distribution in different culture compartments (apical surface liquid, epithelial culture, and basal side medium) at various time points following acute exposure to 13C12-labeled trehalose. We found that 13C12-trehalose was metabolized into 13C6-glucose. The data was then used to model the kinetics of trehalose disappearance from the apical surface of bronchial cultures. Secondly, we evaluated the potential adverse effects of nebulized trehalose on the bronchial cultures after they were acutely exposed to nebulized trehalose up to a level just below its solubility limit (50 g/100 g water). We assessed the ciliary beating frequency and histological characteristics. We found that nebulized trehalose did not lead to marked alteration in ciliary beating frequency and morphology of the epithelial cultures. The in vitro testing approach used here may enable the early selection of excipients for future development of inhalation products.