Vaping can provoke the same cellular response as cigarette smoking, reports a new study. The findings of the study are published in the American Journal of Respiratory and Critical Care Medicine.// In a study, the UNC scientists found that the lungs of vapers - like the lungs of smokers - have elevated levels of protease enzymes, a condition is known to cause emphysema in smokers. The researchers also found that the nicotine in vaping liquids is responsible for the increase in protease enzymes.
‘E-cigarettes are just as harmful to lung health as traditional cigarettes. ’"Our findings in this study indicate that vaping may not be safer than cigarette smoking," said senior study author Robert Tarran, Ph.D., a professor in the department of cell biology and physiology and member of the Marsico Lung Institute at the UNC School of Medicine.
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The U.S. Centers for Disease Control and Prevention (CDC) has estimated that in 2014, about 9 million adults in the country were regular vapers and that close to 30 million had tried vaping at least once. But vaping on this scale has been going on for less than a decade, and so the long-term health effects of vaping are not yet well understood.
Tarran and colleagues in the study measured levels of three key protease enzymes in lung fluid sampled from 41 subjects - nonsmokers, smokers, and vapers. The three protease enzymes are neutrophil elastase and matrix metalloproteases 2 and 9. Immune cells in the lungs are known to secrete these enzymes at higher levels in a reaction to cigarette smoke. Chronic overactivity of these protein-chewing enzymes damages the tiny sensitive air sac structures in the lungs that allow people to breathe. In smokers, this damage is thought to be the cause of emphysema, a form of chronic obstructive pulmonary disease (COPD) involving progressive shortness of breath and for which there is no cure.
The UNC scientists found that the levels of these three proteases were significantly elevated in both smokers and vapers, but not in nonsmokers. This finding suggests vaping, like smoking, may promote emphysema.
The scientists also found evidence that nicotine in vaping liquids is the cause of the elevated-protease reaction. When Tarran's team administered nicotine to immune cells cultured in the laboratory - at concentrations like those seen in vapers sputum and lung fluid - they observed that the cells overproduced the proteases. And this overproduction increased when the researchers exposed the immune cells to higher nicotine levels.
Tarran noted that the findings are not the first to warn of vaping's potential adverse health effects. A different study in 2018, from a team led by UNC Marsico Lung Institute researcher Mehmet Kesimer, Ph.D., found that sputum from vapers and smokers contained elevated levels of emphysema-promoting proteases and other immune defense proteins.
Tarran and his colleagues plan to follow up with their new study with a larger study of lung protease levels in hundreds of participants.