Smoking linked with increased expression of ACE2 gene in lungs

Reuters - 11/09/2020 - New research shows that the gene encoding angiotensin-converting enzyme 2 (ACE2), a protein that facilitates SARS-CoV-2 entry, is present at higher levels in the nose than in the bronchus, indicating that the nose may be more easily infected.

Current smoking appears to increase the expression of this gene, specifically in the lower airways, while having no effects on expression in the nose, lead researcher Alen Faiz from University of Technology Sydney, in Australia, told Reuters.

"This may indicate that smokers may be at risk for a more severe course of the infection by allowing its spread to the lung where most of the damage occurs," he said by email. "This higher level of ACE2 in current smokers was shown to be lower in individuals that stop smoking for more than a month, indicating that quitting smoking may be beneficial to reducing the risk for severe COVID-19."

Smoking just three cigarettes is sufficient to increase the levels of ACE2 within one day in adults, Faiz said.

His team's preliminary data also suggested that second-hand smoke exposure of one-year-old children increased ACE2 expression in their airways.

Inhaled corticosteroids were found to decrease ACE2 expression over six months of treatment, which may help explain the observation that patients with obstructive airway diseases do not appear to be overrepresented among patients hospitalized with severe COVID-19.

"The current study provides the first longitudinal evaluation of ACE2 expression in samples from the airways on a limited number of patients, which deserves expansion in subsequent studies," Faiz said.

At this point, he emphasized, it's not clear that higher expression of the ACE2 receptors is linked with the severity of COVID- 19 infection, "however, this is a theory based on the known mechanism of COVID-19 infection."

The research appeared online in a preprint in advance of peer review.

By Reuters Staff

SOURCE: https://bit.ly/3lQHadT medRxiv, online September 3, 2020.



Posted on 11 September 202016 September 2020