Electronic Cigarette Solvents, JUUL E-Liquids, and Biomarkers of Exposure: In Vivo Evidence for acrolein and Glycidol in E-Cig-Derived aerosols.

Introduction:
This article reports on a study examining the effects of electronic cigarette (e-cigarette) aerosol exposure on mice and humans. The study measured the levels of certain biomarkers in the urine of mice and humans after e-cigarette use to determine the potential health risks associated with e-cigarette use.

Key Points:

* The study found that acute exposure to e-cigarette aerosols or a mixture of propylene glycol and vegetable glycerin (PG:VG) significantly increased the urinary excretion of acrolein and glycidol metabolites in mice.
* In humans, the use of e-cigarettes led to an increase in the urinary levels of 2,3-dihydroxypropylmercapturic acid (23hPMa) but not 3-hydroxypropylmercapturic acid (3hPMa).
* The study also found that exposure to aerosols derived from PG:13C3-VG resulted in a significant increase in the 13C3-enrichment of both urinary metabolites 13C3-3hPMa and 13C3-23hPMa in mice.
* The findings suggest that the adverse health effects of e-cigarettes may be attributable in part to reactive compounds formed through the process of aerosolizing nicotine.
* The study also supports the notion that 23hPMa, but not 3hPMa, may be a relatively specific biomarker of e-cigarette use.
* The study used a defined e-cig platform and exposed mice to e-cigarette aerosols for 6 hours, with total suspended particulate matter monitored in real time.
* The study also used 13C3-VG to probe for 13C-enrichment in urinary metabolites using UPLC-qTOF mass spectrometry.

Main Message:
The study provides evidence that the thermal decomposition of vegetable glycerin in e-cigarette solvents leads to the generation of acrolein and glycidol, which may contribute to the adverse health effects of e-cigarettes. The findings also suggest that 23hPMa may be a relatively specific biomarker of e-cigarette use. The study highlights the importance of continued research into the health effects of e-cigarette use and the need for appropriate regulations to protect public health.

Lorkiewicz P, Keith R, Lynch J, et al. Electronic Cigarette Solvents, JUUL E-Liquids, and Biomarkers of Exposure: In Vivo Evidence for acrolein and Glycidol in E-Cig-Derived aerosols. Chemical research in toxicology. 2022;35(2):283-292. doi:10.1021/acs.chemrestox.1c00328