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Cancer Prev Res (Phila). 2019 Oct 16. pii: canprevres.0400.2019. doi: 10.1158/1940-6207.CAPR-19-0400. [Epub ahead of print]

Effects of Electronic Cigarette Constituents on the Human Lung: A Pilot Clinical Trial.

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The Ohio State University.
Comprehensive Cancer Center, Ohio State University.
Department of Epidemiology and Environmental Health, University at Buffalo, State University of New York.
Division of Medical Oncology, The Ohio State University College of Medicine.
Department of Biomedical Informatics, The Ohio State University.
Department of Biomedical Informatics' Center for Biostatistics, Ohio State University.
Comprehensive Cancer Center, Ohio State University


E-cig use is continuing to increase, particularly among youth never-smokers, and is used by some smokers to quit. The acute and chronic toxicity of e-cig use is unclear generally in the context of increasing reports of inflammatory-type pneumonia in some e-cig users. To assess lung effects of e-cigs without nicotine or flavors, we conducted a pilot study with serial bronchoscopies over 4 weeks in 30 never-smokers, randomized either to a four-week intervention with the use of e-cigs containing only 50% propylene glycol (PG) and 50% vegetable glycerine (VG) or to a no-use control group. Compliance to the e-cig intervention was assessed by participants sending daily puff counts and by urinary propylene glycol (PG). Inflammatory cell counts and cytokines were determined in bronchoalveolar lavage (BAL) fluids. Genome-wide expression, microRNA, and mRNA were determined from bronchial epithelial cells. There were no significant differences in changes of BAL inflammatory cell counts or cytokines between baseline and follow-up, comparing the control and e-cig groups. However, in the intervention but not the control group, change in urinary PG as a marker of e-cig use and inhalation, was significantly correlated with change in cell counts (cell concentrations, macrophages, and lymphocytes) and cytokines (IL-8, IL-13, and TNF-α), although the absolute magnitude of changes was small. There were no significant changes in mRNA or microRNA gene expression. Although limited by study size and duration, this is the first experimental demonstration of an impact of e-cig use on inflammation in the human lung among never-smokers.

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