Allergic contact dermatitis and electronic cigarettes: Is nickel to blame?

Introduction:
This article presents a study on the characterization of the Borgwaldt LM4E system for in vitro exposures to undiluted aerosols from next generation tobacco and nicotine products (NGPs). The study aimed to simplify the exposure scenario for NGP aerosols and bypass the dilution step required in traditional cigarette smoke exposure systems. The LM4E system was used to generate undiluted aerosols from an e-cigarette and a tobacco heating product (THP), and nicotine delivery was measured at source and in the exposure chamber. Cell viability studies were performed using H292 human lung epithelial cells exposed to undiluted aerosols from the e-cigarette and THP.

Key Points:

* The LM4E system is designed for use with puffing devices such as e-cigarettes and THPs.
* The system is compact and comparatively simple, requiring only one electricity supply to operate.
* The software is intuitive and contains all the industry standard puffing regimes.
* The pump module delivers undiluted aerosol from the back of the system.
* The aerosol delivery lines were passed into an adjacent benchtop in-cubator set to 37 °C, housing in vitro exposure chambers containing cell cultures for exposures at the ALI.
* H292 cells were exposed to undiluted e-cigarette aerosol for 2 h (240 puffs) or undiluted THP aerosol for 1 h (120 puffs).
* There were positive correlations between puffing number and nicotine in the exposed culture media.
* NRU determined cell viability for e-cigarettes after 2 h exposure resulted in 21.5 ± 17.0% cell survival, while full cytotoxicity was reached after 1-hour exposure for the THP.

Main Message:
The study demonstrates the characterization and assessment of the Borgwaldt LM4E system for in vitro exposures to undiluted aerosols from NGPs. The system was found to be suitable for generating undiluted aerosols from e-cigarettes and THPs, and the nicotine delivery was measurable at source and in the exposure chamber. Cell viability studies showed that undiluted aerosols from e-cigarettes and THPs can cause cytotoxicity in H292 human lung epithelial cells. The study suggests that the LM4E system can be a useful tool for regulatory purposes in assessing the potential biological impact of NGPs. However, the authors note that the system should be suitable and adaptable to the various devices as the devices are rapidly evolving.

Adamson, Jason, Tomasz Jaunky, David Thorne, and Marianna D. Gaça. “Characterisation of the Borgwaldt LM4E System for in Vitro Exposures to Undiluted Aerosols from next Generation Tobacco and Nicotine Products (NGPs).” Food and Chemical Toxicology 113 (March 2018): 337–44. https://doi.org/10.1016/j.fct.2018.02.005.