The Effect of Flavored E-cigarettes on Murine Allergic Airways Disease

David G Chapman,Minara Aliyeva,Charles G Irvin,Karolyn G Lahue,Yvonne M W Janssen-Heininger,Jennifer L Ather,Nirav Daphtary,Dylan T Casey,Jos L Van Der Velden

doi:10.1038/s41598-019-50223-y

Abstract

Flavored e-cigarettes are preferred by the majority of users yet their potential toxicity is unknown. Therefore our aim was to determine the effect of selected flavored e-cigarettes, with or without nicotine, on allergic airways disease in mice. Balb/c mice were challenged with PBS or house dust mite (HDM) (Days 0, 7, 14–18) and exposed to room air or e-cigarette aerosol for 30 min twice daily, 6 days/week from Days 0–18 (n = 8–12/group). Mice were exposed to Room Air, vehicle control (50%VG/%50PG), Black Licorice, Kola, Banana Pudding or Cinnacide without or with 12 mg/mL nicotine. Mice were assessed at 72 hours after the final HDM challenge. Compared to mice challenged with HDM and exposed to Room Air, nicotine-free Cinnacide reduced airway inflammation (p = 0.045) and increased peripheral airway hyperresponsiveness (p = 0.02), nicotine-free Banana Pudding increased soluble lung collagen (p = 0.049), with a trend towards increased airway inflammation with nicotine-free Black Licorice exposure (p = 0.089). In contrast, all e-cigarettes containing nicotine suppressed airway inflammation (p < 0.001 for all) but did not alter airway hyperresponsiveness or airway remodeling. Flavored e-cigarettes without nicotine had significant but heterogeneous effects on features of allergic airways disease. This suggests that some flavored e-cigarettes may alter asthma pathophysiology even when used without nicotine.

Highlights

Electronic cigarette (e-cigarette) use has dramatically increased in recent years due to its portrayal as a healthier alternative to tobacco cigarettes
There was no effect of house dust mite (HDM) on weight in female or male mice exposed to e-cigarette with or without nicotine (p ≥ 0.2 for all)
Male mice exposed to PG/VG, Black Licorice and Cinnacide with nicotine had reduced weight compared to Room Air exposed mice (p < 0.05 for all)

Summary

Introduction

Electronic cigarette (e-cigarette) use has dramatically increased in recent years due to its portrayal as a healthier alternative to tobacco cigarettes. Despite the high use of flavored e-cigarettes and the potential toxicity, little is known as to the adverse effects of flavored e-cigarettes on lung function and respiratory health. Asthmatics are susceptible to the effects of toxic, inhaled substances such as tobacco, with tobacco smoking asthmatics reporting worse asthma control, more unscheduled health care visits, and a greater requirement for oral corticosteroids[12] This increased disease severity is due to both worse lung function[13] and greater severity of airway hyperresponsiveness[14]. Since e-cigarettes contain numerous toxic compounds and reduce lung function following acute use, our objective was to determine the effect of flavored e-cigarettes on the development and severity of allergic airways disease (Fig. 1). Black Licorice was chosen as a flavor distinct from the aforementioned flavors

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Conclusion