AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Developing High-Throughput Screening Approaches for E-liquids and Flavor Constituents
M. FLORI SASSANO, Eric Davis, Sarah Sizer, Shernita Lewis, Robert Tarran, University of North Carolina at Chapel Hill
Abstract Number: 106 Working Group: Electronic Cigarettes - Health Effects
Abstract E-cigarettes deliver nicotine without combusting tobacco. Whilst tobacco smoking has declined since the 1950s, e-cigarette use has increased, attracting both former tobacco smokers and never smokers. E-cigarette liquids (e-liquids) are often a propylene glycol/vegetable glycerin (PG/VG) vehicle containing nicotine and flavorings. To date, neither e-cigarette devices, nor e-liquids, are regulated by the FDA. Since little is known about the potential toxicity of e-liquids, we designed a high-throughput assay to assess potential harm of the 7,000 different e-liquids that are commercially available.
To validate this assay, we plated HEK293T cells, which were previously used as a tobacco exposure model$^1 in 384-well plates. Using an imaging-plate reader, we acquired bright-field images every 2h for 4h in the plate reader at 37°C/5% CO$_2. Cells were entering the log phase of growth at this time and were subsequently treated with e-liquid/vehicle and imaged for an additional 18h. After, cells were stained with calcein-AM and propidium iodide for live/dead measurements, respectively. Growth curves were created from bright-field images. Using this approach, ~150 e-liquids were screened as well as a dose response to PG/VG.
Of the 150 e-liquids tested, ~50% prevented growth or caused a reduction in cell numbers at a 1% dilution. Our future approach is to complete dose response curves on the most toxic e-liquids. Our data demonstrates that we can now test ~70 e-liquids per plate, suggesting that this approach is valid to screen all available e-liquids. We conclude that (i) PG/VG is itself potentially toxic at high concentrations and (ii) that many e-liquids have the potential to affect cell viability/proliferation. A full investigation into e-liquid toxicity will help inform the FDA as to how e-liquids should be regulated. However, further investigation is required to fully understand this phenomenon.
Funded by NIH/FDA (P50-HL-120100).
1. Rasmussen et al. (2014). JBC 289(11), 7671–7681.