Evaluation of Acute Exposure to Combustible and Novel Tobacco Products Using an In Vitro Human Airway Organ Tissue Equivalent Model

Despite the well-known risks of tobacco use, tobacco exposure remains a major contributor to morbidity and mortality worldwide. Although cigarette use has declined, the popularity of novel tobacco products (NTPs), such as electronic cigarettes (ECs) and heated tobacco products (HTPs), has increased. Given the evolving landscape of the tobacco industry, robust in vitro models are needed to evaluate the potential for harm of novel products on the airways. We applied a 3D in vitro human airway organ tissue equivalent (OTE) model to evaluate its ability to characterize the acute effects of aerosol exposure from a combustible cigarette, an HTP, and two ECs using a VITROCELL VC1 Smoking Machine. Each product was tested using a nicotine-matched single exposure dose, providing a standardized benchmark relevant to real-world use. To deliver comparable amounts of nicotine (~35-38 μg), exposures ranged from 20 to 64 min depending on the product. Following exposure, OTEs were evaluated for cytotoxicity, oxidative stress, epithelial barrier function, ciliary function, inflammatory cytokine release, and inflammatory gene expression changes. Compared to cigarettes, NTP exposures resulted in reduced OTE cytotoxicity and inflammation. HTP exposure resulted in moderate cytotoxicity and oxidative stress, an increased inflammatory response, reduced epithelial barrier function, and temporary impairment of ciliary function. For the selected nicotine-matched dose, neither EC notably induced cytotoxicity nor inflammation or disrupted epithelial barrier or ciliary function. This work establishes a methodology for comparing NTPs using a physiologically relevant human in vitro model and supports further examination of NTPs using delivered nicotine as a benchmark.