Cinnamaldehyde in flavored e-cigarette liquids temporarily suppresses bronchial epithelial cell ciliary motility by dysregulation of mitochondrial function

Introduction:
This text discusses a study examining the effects of cinnamaldehyde, a common flavoring agent in e-cigarettes, on bronchial epithelial cell ciliary motility and mitochondrial function. The study compares the effects of cinnamaldehyde-containing e-liquids, vaped aerosol, and cinnamaldehyde alone on human bronchial epithelial (hBE) cells and investigates the molecular drivers of impaired cilia function. The study found that in sheep tracheal epithelial cells, exposure to cinnamaldehyde, a flavoring agent used in e-cigarettes, disrupts mitochondrial respiration and glycolytic function, reduces intracellular aTP levels, and impairs cilia motility. These findings suggest that inhalational exposures to food-safe flavorings like cinnamaldehyde may have unintended and potentially harmful respiratory effects. Further research is needed to determine the specific exposure concentrations that lead to these effects and to investigate how these in vitro findings translate to e-cigarette users in vivo. The study also highlights a knowledge gap in the toxicological evaluation of inhalation exposures to chemical flavoring agents in e-cigarettes, as well as a misunderstanding among e-cigarette users regarding the safety of inhaling these agents.

Clapp, Phillip W., Katelyn S. Lavrich, Catharina a. Van heusden, Eduardo R. Lazarowski, Johnny L. Carson, and Ilona Jaspers. “Cinnamaldehyde in Flavored E-Cigarette Liquids Temporarily Suppresses Bronchial Epithelial Cell Ciliary Motility by Dysregulation of Mitochondrial Function.” american Journal of Physiology-Lung Cellular and Molecular Physiology 316, no. 3 (March 1, 2019): L470–86. https://doi.org/10.1152/ajplung.00304.2018.