Cigarette
smoke (CS) is a major risk factor for cardiovascular and
lung diseases. Because CS is a complex
aerosol containing more than 7,000 chemicals it is challenging to assess the contributions of individual constituents to its overall toxicity. Toxicological profiles of individual constituents as well as mixtures can be however established in vitro, by applying high through-put screening tools, which enable the profiling of Harmful and Potentially Harmful Constituents (HPHCs) of tobacco
smoke, as defined by the U.S. Food and Drug Administration (FDA). For an initial assessment, an impedance-based instrument was used for a real-time, label-free assessment of the compound's toxicity. The instrument readout relies on cell adhesion, viability and morphology that all together provide an overview of the cell status. A dimensionless parameter, named cell index, is used for quantification. A set of different staining protocols was developed for a fluorescence imaging-based investigation and a HCS platform was used to gain more in-depth information on the kind of cytotoxicity elicited by each HPHC. Of the 15 constituents tested, only five were selected for HCS-based analysis as they registered a computable LD50 (< 20 mM). These included 1-aminonaphtalene,
Arsenic (V),
Chromium (VI),
Crotonaldehyde and
Phenol. Based on their effect in the HCS, 1-aminonaphtalene and
Phenol could be identified to induce
mitochondrial dysfunction, and, together with
Chromium (VI) as genotoxic based on the increased
histone H2AX phosphorylation.
Crotonaldehyde was identified as an oxidative stress inducer and
Arsenic as a stress
kinase pathway activator. This study demonstrates that a combination of impedance-based and HCS technologies provides a robust tool for in vitro assessment of CS constituents.