Extreme testing of undiluted e-cigarette aerosol in vitro using an ames air-agar-interface technique

Introduction:
This article reports a study on the mutagenic potential of e-cigarette aerosols using an undiluted per puff basis under extreme testing conditions, employing the ames assay across a broader range of bacterial tester strains. The study used the Vitrocell VC 10 smoking robot to expose bacteria to generated e-cigarette aerosol, delivering up to 900 puffs of undiluted Vype ePen e-cigarette aerosol to four Salmonella typhimurium and one E. coli strain.

Key Points:

* The study found that there were no increases in revertant numbers with exposures to undiluted e-cigarette aerosols above the air control, even with exposures up to 900 puffs.
* Nicotine was assessed across all doses and demonstrated that at the highest exposure, up to 1 mg/mL of nicotine was delivered to the bacterial strains, with no mutagenic response.
* The Vitrocell VC 10 smoking robot was optimized to deliver a more concentrated aerosol, diverting the entire aerosol stream down into the exposure module, significantly amplifying aerosol delivery.
* The positive control responses were observed in all five bacterial tester strains in the presence and absence of metabolic activation, demonstrating the effective performance of the assay.
* The air control was maintained in a separate exposure module as per the treatment condition and used as the “zero puff” benchmark.
* The Vype ePen e-cigarette used in the study is a rechargeable, dual voltage, closed modular system, consisting of two segments, a rechargeable battery section and a replaceable e-liquid cartridge.
* high voltage (4 V) was exclusively used in this study, and Vype ePen e-liquid cartridges contained 18 mg/mL nicotine.

Main Message:
The main message of this study is that e-cigarette aerosols show reduced biological effects in vitro when compared to a scientific reference tobacco product and across matched nicotine doses. The study adds further evidence that Vype e-cigarette aerosols have significantly lower mutagenic activity compared to 3R4F cigarette smoke. The testing of undiluted e-cigarette aerosol is feasible and a practical and realistic option for understanding the full mutagenic potential of e-cigarette aerosols.

Thorne, D., M. hollings, a. Seymour, J. adamson, a. Dalrymple, M. Ballantyne, and M. Gaca. “Extreme Testing of Undiluted E-Cigarette aerosol in Vitro Using an ames air-agar-Interface Technique.” Mutation Research/Genetic Toxicology and Environmental Mutagenesis 828 (april 2018): 46–54. https://doi.org/10.1016/j.mrgentox.2018.01.008.