E-cigarettes appear to trigger the same immune responses that combustible cigarettes trigger, responses that can lead to lung disease, according to new research published in the American Journal of Respiratory and Critical Care Medicine.
Researchers at University of North Carolina Chapel Hill believe theirs is the first study to use human airway samples to explore the harmful effects of e-cigarettes.
The study compared sputum samples from 15 e-cigarette users, 14 current cigarette smokers and 15 non-smokers. They found e-cigarette users uniquely exhibited significant increases in:
- Neutrophil granulocyte- and neutrophil-extracellular-trap (NET)-related proteins in their airways. Although neutrophils are important in fighting pathogens, left unchecked, neutrophils can contribute to inflammatory lung diseases, such as COPD and cystic fibrosis.
- NETs outside the lung. NETs are associated with cell death in the epithelial and endothelium, the tissues lining blood vessels and organs. The authors write that more research is necessary to determine if this increase is associated with systemic inflammatory diseases, such as lupus, vasculitis, and psoriasis.
The study also found that e-cigarettes produced some of the same negative consequences as cigarettes. Both e-cigarette and cigarette users exhibited significant increases in:
- Biomarkers of oxidative stress and activation of innate defense mechanisms associated with lung disease. Among these biomarkers are aldehyde-detoxification and oxidative-stress-related proteins, thioredoxin (TXN), and matrix metalloproteinase-9 (MMP9).
- Mucus secretions, specifically mucin 5AC, whose overproduction has been associated with pathologies in the lung including chronic bronchitis, bronchiectasis, asthma, and wheeze.
Study limitations include the fact that of the 15 e-cigarette users, 5 said they occasionally smoked cigarettes and 12 identified themselves as having smoked cigarettes in the past.
“Our results suggest that e-cigarettes might be just as bad as cigarettes,” said Mehmet Kesimer, PhD, senior study author and associate professor of pathology at the University of North Carolina Chapel Hill. “Our data shows that e-cigarettes have a signature of harm in the lung that is both similar and unique, which challenges the concept that switching from cigarettes to e-cigarettes is a healthier alternative.”
A 2016 Surgeon General’s report found that e-cigarette use increased by 900 percent among high school students from 2011 to 2015. Also in 2016, the Food and Drug Administration extended its regulatory oversight of tobacco products to include e-cigarettes.