Inhalation Toxicology of Vaping Products and Implications for Pulmonary Health
Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada
Department of Medicine, McGill University, Montreal, QC H4A 3J1, Canada
Respiratory Epidemiology and Clinical Research Unit, McGill University Health Centre, Montreal, QC H4A 3J1, Canada
Department of Pathology, McGill University, Montreal, QC H3A 2B4, Canada
Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
Author to whom correspondence should be addressed.
Int. J. Mol. Sci. 2020, 21(10), 3495; https://doi.org/10.3390/ijms21103495
Received: 26 March 2020 / Revised: 28 April 2020 / Accepted: 12 May 2020 / Published: 15 May 2020
(This article belongs to the Special Issue Inhalation Toxicology and Biological Response)
E-cigarettes have a liquid that may contain flavors, solvents, and nicotine. Heating this liquid generates an aerosol that is inhaled into the lungs in a process commonly referred to as vaping. E-cigarette devices can also contain cannabis-based products including tetrahydrocannabinol (THC), the psychoactive component of cannabis (marijuana). E-cigarette use has rapidly increased among current and former smokers as well as youth who have never smoked. The long-term health effects are unknown, and emerging preclinical and clinical studies suggest that e-cigarettes may not be harmless and can cause cellular alterations analogous to traditional tobacco smoke. Here, we review the historical context and the components of e-cigarettes and discuss toxicological similarities and differences between cigarette smoke and e-cigarette aerosol, with specific reference to adverse respiratory outcomes. Finally, we outline possible clinical disorders associated with vaping on pulmonary health and the recent escalation of acute lung injuries, which led to the declaration of the vaping product use-associated lung injury (EVALI) outbreak. It is clear there is much about vaping that is not understood. Consequently, until more is known about the health effects of vaping, individual factors that need to be taken into consideration include age, current and prior use of combustible tobacco products, and whether the user has preexisting lung conditions such as asthma and chronic obstructive pulmonary disease (COPD).