Background: One of the leading causes of preventable death worldwide is cigarette smoking. Therefore, alternative products such as e-cigarettes (e-cigs) have become increasingly popular and marketed as less harmful. As e-cigs are a relatively new product, much is still unknown about the health effects.

Aims and objectives: To investigate effects of e-cig inhalation (vaping) on lung tissue, we collected blood samples from healthy occasional smokers, following brief vaping with and without nicotine. Lung-related extracellular vesicles (EVs) were measured. EVs are membrane-bound vesicles released into the extracellular space upon activation or apoptosis of cells and express proteins similar to their parent cell.

Methods: In a randomized, double-blind, cross-over study, 22 subjects vaped 30 puffs over 30 minutes of e-cig liquid with and without nicotine. Blood samples were collected at baseline, 30 and 105 minutes after exposure. Using flow cytometry, lung-related EVs were measured. Analyzed markers were angiontensin-1 converting enzyme, aldehyde dehydrogenase 3B1, palate, lung and epithelial clone (PLUNC), complement component 3, macrophage inflammatory protein 1 alpha, uteroglobin and beta-subunit of propyl 4-hydroxylase.

Results: Significant increases in all seven markers were seen after exposure to e-cig vape with nicotine. No significant changes were found after exposure to the nicotine-free vape.
Conclusion: This novel study demonstrates that inhaled nicotine induces lung tissue stress and subsequent EV release to the bloodstream. The release of lung-related EVs could be an important factor that may increase pulmonary inflammation and vascular stress when using e-cigarettes.