Published in JCI Insightthis work carried out by National Jewish Health also shows, in pre-clinical models, a lower effectiveness of pulmonary defenses against SARS-CoV-2. A scientific alert which will however need to be confirmed in humans.
In less than 24 hours, the lung already shows signs of stress
Deep within the lung is a particularly delicate region: the distal lung, where exchanges between air and blood take place. This is precisely the area that National Jewish Health researchers studied.
They exposed human lung cells and human lung fragments to e-cigarette aerosol. Result : in less than 24 hoursthe protective barrier of the fabric became more permeable. Cellular stress increased, cell repair slowed and cell death progressed.
“Our results suggest that even short-term exposure to vaping can initiate damage in the deepest, most delicate regions of the lung.”explains Irina Petrache, pulmonologist and head of the Division of Pulmonology, Resuscitation and Sleep Medicine at National Jewish Health.
But the most disturbing thing appears when the researchers stop the exhibition.
Five days of vaping, ten days later: traces still present
In another part of the study, golden Syrian hamsters inhaled the aerosol for five daysunder conditions corresponding to occasional exposure.
Ten days after stopping, the animals seemed to be doing well: no weight loss or obvious clinical signs. Yet their lungs retained markers of cellular stress and programmed cell death.
The activity of hundreds of genes was also modified: approximately 200 were more expressed and 300 less expressed.
In other words, stopping the exposure did not mean an immediate return to the initial state.
“Importantly, some effects persisted after exposure ended and altered the immune response to subsequent viral infection“underlines Irina Petrache.
This persistence led researchers to examine another question: does a lung weakened by vaping defend itself as well against a virus?
Faced with SARS-CoV-2, less effective antiviral defenses
Researchers observed disruption of immunity
Th1essential in the fight against viral infections. Several genes involved in the antiviral response, including Ifit1, Isg15 and Nfkbiawere also less active. In hamsters exposed to the aerosol before their infection with SARS-CoV-2, the viral load in the respiratory tract was higher.
The observed mechanism is therefore consistent: the aerosol disrupts the pulmonary barrier, increases cell stress and seems to modify certain immune defenses.
This does not mean that vaping always causes lung infection or disease. The study is preclinical and does not yet allow these results to be directly extrapolated to all vapers.
A warning signal, not yet a definitive conclusion
The researchers themselves emphasize the need to confirm these observations in humans. But their results raise an important question: what happens when these attacks, instead of lasting five days, are repeated for months or years?
According to the team, repeated exposure could maintain cellular damage and disrupt the normal repair mechanisms of lung tissue, ultimately leading to a potential risk of chronic lung disease.
The study therefore does not say that a few days of vaping is enough to make you sick. It shows something more subtle, but essential: the lung responds quickly to exposure and some biological effects may persist after it stops.
Behind a vapor that appears light and fleeting, researchers observe an organ which, at the cellular level, is already under tension.