Vaping and Lung Inflammation and Injury

Abstract

The use of electronic (e)-cigarettes was initially considered a beneficial solution to conventional cigarette smoking cessation. However, paradoxically, e-cigarette use is rapidly growing among nonsmokers, including youth and young adults. In 2019, this rapid growth resulted in an epidemic of hospitalizations and deaths of e-cigarette users (vapers) due to acute lung injury; this novel disease was termed e-cigarette or vaping use-associated lung injury (EVALI). Pathophysiologic mechanisms of EVALI likely involve cytotoxicity and neutrophilic inflammation caused by inhaled chemicals, but further details remain unknown. The undiscovered mechanisms of EVALI are a barrier to identifying biomarkers and developing therapeutics. Furthermore, adverse effects of e-cigarette use have been linked to chronic lung diseases and systemic effects on multiple organs. In this comprehensive review, we discuss the diverse spectrum of vaping exposures, epidemiological and clinical reports, and experimental findings to provide a better understanding of EVALI and the adverse health effects of chronic e-cigarette exposure.

Keywords: ENDS; EVALI; acute lung injury; e-cigarette aerosols; e-cigarette or vaping use-associated lung injury; electronic nicotine delivery systems; inflammatory lung disease; systemic inflammation.

Figure 1

Toxic substances detected in e-cigarette aerosols and e-liquids. Toxic substances detected in e-cigarettes include toxicants (chemicals, nanoparticles, and heavy metals) and toxins (endotoxin and β-glucans). Figure adapted from images created with BioRender.com.

Figure 2

Mechanistic overview of the adverse effects of electronic cigarettes on the lung. As a primary organ, the lung is damaged and impaired by electronic cigarette use. Figure adapted from images created with BioRender.com. Abbreviations: γH2AX, gamma H2AX; ROS, reactive oxygen species.

Figure 3

Adverse effects of electronic cigarettes on human health. As the site of the contact with inhaled toxic chemicals, the lungs are directly damaged by electronic cigarette use, but multiple organs are damaged by systemic adverse effects. Figure adapted from images created with BioRender.com.