Abstract
E-cigarettes emit less particulates and toxins than standard cigarettes but they still expose users to a multitude of potentially harmful compounds. Given their growing use, there is a strong public health need to assess the safety and lung effects of e-cigarettes. This study developed an in vivo model of e-cigarette exposure in A/J mice using a small animal nebulizer. Cohorts of mice (n=8 per group) were exposed for 1 hour/day, 5 days a week for 4 months to either nebulized PBS, vehicle (50% propylene glycol/50% vegetable glycerin), e-cigarette liquid (American eLiquid Store) containing 18 mg/ml nicotine in 50%PG/50% VG or e-cigarette liquid containing 36 mg/ml nicotine in 50% PG/50% VG. Exposure to e-cigarette vapor with nicotine increased lung cytokine and protease expression, mucin staining in the airways, caspase 3/7 activity in the tissue and TUNEL staining in the lung parenchyma.
In addition, e-cigarettes induced emphysema and airway hyperreactivity while the vehicle had no effect.
Thus, this study shows for the first time that e-cigarette exposure causes asthma and emphysema in vivo.
- © 2014 ERS