E-Cigarette Vapour Increases ACE2 and TMPRSS2 Expression in a Flavour- and Nicotine-Dependent Manner

Area of Science:

• Pulmonology
• Virology
• Toxicology

Background:

• COVID-19 primarily affects the respiratory system but can cause multi-system failure.
• Smoking is linked to worse COVID-19 outcomes due to increased ACE2 in lung cells.
• The impact of e-cigarette use on COVID-19 risk is not well understood.

Purpose of the Study:

• To investigate if e-cigarette use increases the risk of SARS-CoV-2 infection.
• To examine the effects of cigarette smoke extract (CSE) and e-cigarette vapor extract (EVE) on COVID-19 related gene expression.

Main Methods:

• Exposed human bronchial epithelial cells (NHBE) and macrophages (MDM) to CSE, nicotine, or flavored EVE.
• Assessed the expression of SARS-CoV-2 recognition receptors ACE2 and TMPRSS2.

Main Results:

• CSE and tobacco EVE increased ACE2 expression in MDMs.
• CSE, nicotine, banana, and chocolate EVE upregulated ACE2 in NHBE cells (>2-fold).
• TMPRSS2 expression increased with CSE or nicotine EVE in NHBE cells, but not MDMs.

Conclusions:

• Flavors in e-cigarettes can increase ACE2 expression in various cell types.
• Nicotine and CSE may increase TMPRSS2 expression in airway epithelial cells.
• The risk of COVID-19 infection cannot be excluded for e-cigarette users (vapers).