Firsthand and Secondhand Exposure Levels of Maltol-Flavored Electronic Nicotine Delivery System Vapors Disrupt amino acid Metabolism.

Introduction:
This text discusses a study examining the effects of the flavorant maltol, commonly found in electronic nicotine delivery system (ENDS) vapors, on lung metabolism. The study used high-resolution metabolomics to investigate the impacts of firsthand and secondhand exposure to maltol-flavored ENDS vapors on lung metabolism.

Key Points:

* The study found that maltol in e-liquids impacts lung airway epithelial cell metabolism at both firsthand and secondhand exposure levels.
* The effects of maltol were most notably seen in amino acid metabolism while oxidative stress was observed with exposure to all ENDS vapors including e-liquids alone and maltol-contained e-liquids.
* Many effects of firsthand exposure were also observed with secondhand exposure, suggesting a need for systematic investigation of both firsthand and secondhand effects of flavored ENDS vapors on lung metabolism and risk of lung disease.
* The study used a human lung bronchial epithelial cell line (BEaS-2B) and exposed the cells to ENDS vapor generated with unflavored e-liquid with or without nicotine, and e-liquid with nicotine treatments with or without maltol.
* Metabolomics analyses were performed to examine the effects of maltol addition to e-liquid containing nicotine and test the effects of nicotine addition to e-liquid.
* The study found that maltol had effects in addition to those from nicotine, and an experimental design was used to test the biologically most relevant question of exposure to maltol at firsthand and secondhand levels as they occur from ENDS use.
* Pathway enrichment analyses showed that both firsthand and secondhand exposure levels to maltol-flavored ENDS vapors disrupt metabolism of amino acids, as well as other pathways.

Main Message:
The study highlights the potential harmful effects of the flavorant maltol in ENDS vapors on lung metabolism. The findings suggest that both firsthand and secondhand exposure to maltol-flavored ENDS vapors can disrupt metabolism of amino acids, which may contribute to the risk of lung disease. These results emphasize the importance of further research on the potential health impacts of flavored ENDS vapors and the need for regulatory measures to protect public health.

Jarrell ZR, Smith MR, he X, Orr M, Jones DP, Go YM. Firsthand and Secondhand Exposure Levels of Maltol-Flavored Electronic Nicotine Delivery System Vapors Disrupt amino acid Metabolism. Toxicological sciences : an official journal of the Society of Toxicology. 2021;182(1):70-81. doi:10.1093/toxsci/kfab051