The respiratory epithelium in the era of vaping: insights from <i>in vitro</i> , <i>in vivo</i> and human studies
Anvita Gandhi, Claire E. Lee, A. Beaumont, Sarah Ozeki, Caleb J Parambil, Russell P. Bowler, Fariba Rezaee
Abstract
Since their market introduction in 2007, electronic cigarettes (e-cigarettes) have rapidly gained popularity, often marketed as a safer alternative to traditional smoking. Their appeal, especially among adolescents, is heightened by the wide variety of available flavours. However, both acute and chronic exposure to e-cigarettes has been linked to adverse health effects, including oxidative stress, inflammation and airway barrier dysfunction. While several cell culture and animal studies have explored the effects of e-cigarette exposure on the respiratory tract, comprehensive comparisons of the cellular and physiological outcomes across in vitro , in vivo and human studies remain limited. In this review, we evaluate in vitro and in vivo models of e-cigarette exposure, alongside human studies examining the respiratory outcomes of e-cigarette use. Common in vitro models, such as human bronchial epithelial cells and primary lung fibroblasts, have been exposed to e-cigarettes, with assessments including cell viability and cytokine release. Similarly, in vivo models using mice or rats exposed to e-cigarette aerosols or extracts have revealed effects ranging from inflammation to lung tissue damage. Additionally, we review human studies that track biomarker changes to directly assess the impact of e-cigarette smoke on participants' respiratory health. By integrating findings from diverse approaches, we aim to provide greater insight on the impact of e-cigarettes on lung health that will guide future research in selecting the most appropriate models for studying airway damage. Ultimately, this synthesis of research will contribute to advancing the scientific dialogue on e-cigarette use and its implications for respiratory health.