UC San Diego

As alternatives to combustible tobacco and marijuana, nicotine e-cigarettes and tetrahydrocannabinol (THC) vapes continue to grow in popularity and use. With new forms of inhalants, however, comes new and unknown impacts on users’ health. Identifying and understanding these effects becomes increasingly critical as young adults continue to perceive e- cigarettes and THC vapes as less dangerous alternatives. Further, with the e-cigarette or vaping device use associated lung injury (EVALI) epidemic that primarily occurs in THC e-cigarette users, there is high concern that vaped THC causes lung inflammation. Here we assessed differences in lung function and the inflammatory state of e-cigarette users, THC vapers, dual users of nicotine and THC, and non-vaping/non-smoking controls by measuring spirometry, saliva and sputum production, inflammatory immune cells, plasma biomarkers, and phenotypic differences in complete blood counts (CBCs) and peripheral blood mononuclear cells (PBMCs).

Nasal cytology, induced sputum, saliva, spirometry, and blood samples were collected from nicotine and THC e-cigarette users and controls who underwent informed consent as part of our IRB approved protocol at the University of California San Diego (UCSD). Overall, inhalant users showed elevated sputum production, neutrophilia, and inflammatory immune cell levels in the airways relative to controls. Further, inhalant users had altered gene expression both systemically and in the airways. Based on these observations, inhalant users are at risk for active inflammation, disease, and potential tissue damage. Further, detecting differences for dual users, but not e-cigarette or THC users alone, may suggest an additive effect from using multiple different types of inhalants.