Dual and poly-use of novel and conventional nicotine and tobacco product use in Europe: Challenges for population health, regulatory policies, and the ways ahead

[Intended and unintended effects of e-cigarettes in clinical studies: a plea for (more) transparency]

E-cigarettes are used in clinical trials to facilitate smoking cessation. Due to the health risks associated with the use of e-cigarettes, the results of clinical trials should be fully reported, including continued exclusive use and dual use of tobacco and e-cigarettes. Nicotine cessation outcomes should be reported as the primary endpoint as well as the analysis of tobacco cessation alone. As there is currently no robust evidence that reducing cigarette consumption provides substantial health benefits, cigarette consumption reduction should not be used as a health outcome in clinical trials. Continued nicotine dependence should be included as an "adverse event" in the reporting of trial results.

Do alternative tobacco products induce less adverse respiratory risk than cigarettes?

RATIONALE

Due to the relatively short existence of alternative tobacco products, gaps exist in our current understanding of their long-term respiratory health effects. We therefore undertook the first-ever side-by-side comparison of the impact of chronic inhalation of aerosols emitted from electronic cigarettes (EC) and heated tobacco products (HTP), and combustible cigarettes (CC) smoke.

OBJECTIVES

To evaluate the potential differential effects of alternative tobacco products on lung inflammatory responses and efficacy of vaccination in comparison to CC.

METHODS

Mice were exposed to emissions from EC, HTP, CC, or air for 8 weeks. BAL and lung tissue were analyzed for markers of inflammation, lung damage, and oxidative stress. Another group was exposed for 12 weeks and vaccinated and challenged with a bacterial respiratory infection. Antibody titers in BAL and sera and pulmonary bacterial clearance were assessed.

MAIN RESULTS

EC- and HTP-aerosols significantly augmented lung immune cell infiltrates equivalent to that achieved following CC-exposure. HTP and CC significantly increased neutrophil numbers compared to EC. All products augmented numbers of B cells, T cells, and pro-inflammatory IL17A+ T cells in the lungs. Decreased lung antioxidant activity and lung epithelial and endothelial damage was induced by all products. EC and HTP differentially augmented inflammatory cytokines/chemokines in the BAL. Generation of immunity following vaccination was impaired by EC and HTP but to a lesser extent than CC, with a CC > HTP > EC hierarchy of suppression of pulmonary bacterial clearance.

CONCLUSIONS

HTP and EC-aerosols induced a proinflammatory pulmonary microenvironment, lung damage, and suppressed efficacy of vaccination.