New evidence that e-cigs damage human lungs more than conventional cigs

Boris Reidel and his colleagues at the University of North Carolina just published E-Cigarette Use Causes a Unique Innate Immune Response in the Lung Involving Increased Neutrophilic Activation and Altered Mucin Secretion which adds to the growing case that e-cigarettes have a different risk profile that conventional cigarettes and, at least for some effects, may be more dangerous than conventional cigarettes. 
 
After noting that “e-cigarettes, have become popular … supported by a common assumption that e-cigarette use is harmless and a safe alternative to cigarette smoking. Despite a lack of sufficient health science evidence, e-cigarettes are promoted as cigarette smoking cessation aids in some health care practices.”  
 
To test this assumption, they collected sputum from nonsmokers, smokers, and e-cigarette users and looked to see what proteins connected with immune response in the lungs that protect the linings of airways in the lungs were altered.  They found “a unique e-cigarette-induced innate lung response that includes markers of aberrant neutrophilic response and altered mucin secretion and indicate that the effects of e-cigarettes are overlapping with yet distinct from those observed in otherwise healthy cigarette smokers. These findings challenge the concept that switching from cigarettes to e-cigarettes is a healthier alternative.
 
This extensive degranulation of neutrophils is a feature of lung disorders involving inflammation, such as severe asthma and COPD. 
 
Our friends in England (and a few here in the US, Europe and New Zealand) – and the FDA leadership --  need to start studying these papers and stop repeating the evidence-free nostrum  that e-cigarettes are 95% safer than conventional cigarettes.
 
In terms of the pulmonary end points studied in this paper, e-cigarettes are worse.
 
Here is the abstract:
 
RATIONALE: E-cigarettes have become increasingly popular and little is known about their potential adverse health effects.
OBJECTIVE: To determine the effects of e-cigarette use on the airways.
METHODS: Induced sputum samples from cigarette smokers, e-cigarette users, and non-smokers, were analyzed by quantitative proteomics, and the total and individual concentrations of mucins MUC5AC and MUC5B were determined by light scattering/refractometry and labeled mass spectrometry, respectively. Neutrophil extracellular trap (NET) formation rates were also determined for the same groups.
MEASUREMENTS AND MAIN RESULTS: E-cigarette users exhibited significant increases in aldehyde-detoxification and oxidative stress related proteins associated with cigarette smoke comparing to non-smokers. The levels of innate defense proteins associated with Chronic obstructive pulmonary disease (COPD), such as elastase and matrix metalloproteinase- 9, were significantly elevated in e-cigarette users as well. E-cigarette users' sputum also uniquely exhibited significant increases in neutrophil granulocyte- and NET-related proteins, such as myeloperoxidase, azurocidin, and protein-arginine deiminase 4, despite no significant elevation in neutrophil cell counts. Peripheral neutrophils from e-cigarette users showed increased sensitivity to PMA-induced NETosis. Finally, a compositional change in the gel-forming building blocks of airway mucus, i.e., an elevated concentration of mucin MUC5AC, was observed in both cigarette smokers and e-cigarette users.
CONCLUSIONS: Together, our results indicate that e-cigarette use alters the profile of innate defense proteins in airway secretions, inducing both similar and unique changes relative to cigarette smoking. These data challenge the concept that e-cigarettes are a healthier alternative to cigarettes.
 
The full citation is:  Reidel B, et al.  E-Cigarette Use Causes a Unique Innate Immune Response in the Lung Involving Increased Neutrophilic Activation and Altered Mucin Secretion. Am J Respir Crit Care Med. 2017 Oct 20. doi: 10.1164/rccm.201708-1590OC. [Epub ahead of print] and is available here.
 
The same group also published another study showing elevated levels of markers of pulmonary inflammation in e-cigarettes users simiar to that in smokers (actually a bit higher).  They found other responses in e-cigarette users that were not present in cigarette smokers, suggesting that e-cigarettes have a different risk profile from cigarettes, but that is at least as dangerous in terms of lung disease.