The use of electronic cigarettes, more commonly known as vaping, triggers cellular responses in the lungs similar to those elicited by smoking tobacco cigarettes, which may place e-cigarette users at risk of developing chronic lung diseases, a study says.
Results from the study, “Chronic E-Cigarette Use Increases Neutrophil Elastase and Matrix Metalloprotease Levels in the Lung,” were published in the American Journal of Respiratory and Critical Care Medicine.
Originally developed as a tool to help people quit smoking, e-cigarettes are a type of non-combustible tobacco alternative in which nicotine — the stimulant addictive substance found in tobacco — is mixed with other flavoring agents in an aerosol that is then inhaled.
“Vaping e-cigarettes has been perceived by the general public and some professional bodies as a safer alternative to tobacco smoking,” the researchers wrote. “However, this is controversial, as there are conflicting data regarding their safety, and to date no robust long-term exposure data exist.”
A group of investigators from the University of North Carolina (UNC) School of Medicine discovered that vaping actually triggers cellular responses similar to those found in the lungs of smokers, which are known to increase the risk of emphysema, a severe form of chronic obstructive pulmonary disease (COPD).
“Our findings in this study indicate that vaping may not be safer than cigarette smoking,” Robert Tarran, PhD, professor in the department of cell biology and physiology, member of the Marsico Lung Institute at the UNC School of Medicine, and senior author of the study, said in a press release.
In the study, researchers performed bronchoscopies followed by a bronchoalveolar lavage (BAL) to collect fluid samples to measure the levels of three different proteases — enzymes that break down proteins and whose high levels in the lungs have been linked to the development of emphysema and bronchiectasis — in the lungs of 14 healthy non-smokers, 14 cigarette smokers, and 14 vapers.
(Of note, a bronchoscopy is a procedure in which a physician inserts a flexible, lighted tube into a person’s lungs through the mouth or nose to examine the bronchi; BAL is a procedure that may be performed during a bronchoscopy in which a fluid is squirted into a small portion of the lung and then aspirated to be analyzed.)
Results showed that BAL samples from smokers and vapers contained high levels of all three proteases analyzed — neutrophil elastase, and matrix metalloproteases 2 and 9 — compared to healthy non-smokers, placing both regular smokers and e-cigarette users at risk of developing chronic lung diseases.
These proteases are normally produced by immune cells that travel to the lungs in response to cigarette smoke. Over time, their abnormal high levels and activity start to damage the small air sacs (alveoli) in the lungs, causing shortness of breath that may progress to chronic emphysema.
At the same time, investigators also measured the levels of nicotine found in both BAL and sputum (mucus expelled by coughing) samples in e-cigarette users shortly after vaping.
Using the nicotine concentrations found in these samples, researchers treated immune cells cultured in a lab dish, and found the levels of nicotine were sufficient to stimulate cells to release high amounts of proteases. This increase was even higher when cells were exposed to higher levels of nicotine, suggesting a dose-dependent response.
According to Tarran, this is not the first study showing evidence that vaping may not be safer than tobacco smoking.
A study published last year by another group of researchers at UNC Marsico Lung Institute showed that sputum samples from smokers and vapers contained high levels of proteases and other types of immune defense proteins associated with the development of emphysema.
In addition, a previous study from Tarran and his group demonstrated that vaping liquids actually contain toxic compounds that pose several risks to human health.
More recently, the U.S. Centers for Disease Control and Prevention (CDC) stated in a press release that it is currently investigating 100 cases of young healthy vapers who suddenly developed severe — and in some cases fatal —lung disease.
Tarran and his group are planning to undertake a new study involving a larger group of participants to continue to investigate the impact of vaping on lung health.