Comparison of the effects of e-cigarette vapor with cigarette smoke on lung function and inflammation in mice

Am J Physiol Lung Cell Mol Physiol. 2018 Nov 1;315(5):L662-L672. doi: 10.1152/ajplung.00389.2017. Epub 2018 Aug 9.


Electronic cigarettes (e-cigs) are advertised as a less harmful nicotine delivery system or as a new smoking cessation tool. We aimed to assess the in vivo effects of e-cig vapor in the lung and to compare them to those of cigarette smoke (CS). We exposed C57BL/6 mice for either 3 days or 4 wk to ambient air, CS, or e-cig vapor containing 1) propylene glycol/vegetable glycerol (PG:VG-Sol; 1:1), 2) PG:VG with nicotine (G:VG-N), or 3) PG:VG with nicotine and flavor (PG:VG-N+F) and determined oxidative stress, inflammation, and pulmonary mechanics. E-cig vapors, especially PG:VG-N+F, increased bronchoalveolar lavage fluid (BALF) cellularity, Muc5ac production, as well as BALF and lung oxidative stress markers at least comparably and in many cases more than CS. BALF protein content at both time points studied was only elevated in the PG:VG-N+F group. After 3 days, PG:VG-Sol altered tissue elasticity, static compliance, and airway resistance, whereas after 4 wk CS was the only treatment adversely affecting these parameters. Airway hyperresponsiveness in response to methacholine was increased similarly in the CS and PG:VG-N+F groups. Our findings suggest that exposure to e-cig vapor can trigger inflammatory responses and adversely affect respiratory system mechanics. In many cases, the added flavor in e-cigs exacerbated the detrimental effects of e-cig vapor. We conclude that both e-cig vaping and conventional cigarette smoking negatively impact lung biology.

Keywords: cigarette smoking; electronic cigarettes; lung hyperresponsiveness; lung inflammation; lung mechanics.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Electronic Nicotine Delivery Systems / methods*
  • Electronic Nicotine Delivery Systems / statistics & numerical data
  • Inflammation / etiology*
  • Inflammation / pathology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Oxidative Stress*
  • Respiratory Hypersensitivity / etiology*
  • Respiratory Hypersensitivity / pathology
  • Smoking / adverse effects*
  • Vaping / adverse effects*