Electronic cigarettes (e-cigarettes) offer a promise of a less harmful alternative to smoking tobacco cigarettes. Compared to more than 7,000 constituents that have been identified in tobacco and cigarette smoke, the number of constituents that may be present in e-liquid and e-cigarette aerosol is relatively small. Furthermore, the levels of harmful constituents that have been measured in some e-cigarette aerosols are generally much lower when compared to cigarette smoke. However, emerging data including our preliminary studies suggest that e-cigarette users may be exposed to substantial amounts of aldehydes, experience elevated oxidative damage and inflammation, and form carcinogenic nitrosamine NNN in their saliva. Better assessment of such exposures and resulting macromolecular alterations is critically important in characterizing the potential long-term health effects due to e-cigarette use. Studies in our laboratory focus on saliva and oral cells as biological matrices for assessing exposures and effects from tobacco products and e-cigarettes. Oral cavity is directly exposed to e-cigarette aerosols and oral mucosa is emerging as a promising non-invasive and robust surrogate tissue for assessing molecular alterations in the aerodigestive tract. We develop liquid chromatography (LC)-nanoelectrospray ionization (NSI)-high resolution tandem mass spectrometry (HRMS/MS) methods for simultaneous analysis of a panel of DNA modifications in oral cells, including aldehyde-derived, NNN-derived, and oxidative DNA adducts. The isolated and digested DNA is purified by solid-phase extraction and column chromatography, and analyzed by LC-NSI-HRMS/MS in a pseudo MS<sup>3</sup> mode by applying a source fragmentation voltage of 10 V, followed by higher energy collision dissociation (HCD) fragmentation, isolation widths of 1 amu and product ion spectra acquired at a resolution of 15,000. Challenges associated with the analyses of these biomarkers in the limited amounts of DNA isolated from oral cells will be discussed, optimization of the assays to achieve high sensitivity and selectivity will be outlined, and application of the assays to the analysis of oral cell DNA from habitual e-cigarette users and smokers switching to e-cigarettes will be presented. <br/>

Oral cell-based biomarkers for assessing e-cigarette-derived exposures and effects

2019 Spring National Meeting

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