UCSF

Introduction: Electronic nicotine delivery systems (ENDS; i.e., vaping devices) such as e-cigarettes, heated tobacco products, and newer coil-less ultrasonic vaping devices are promoted as less harmful alternatives to combustible cigarettes. However, the cardiovascular health effects of these devices are understudied. We investigated whether exposure to aerosol from a wide range of ENDS devices with and without nicotine, including a new ultrasonic vaping device, impairs endothelial function. Hypothesis: ENDS aerosols irrespective of nicotine, flavors, and heating coil impair endothelial function comparably to smoke from cigarettes. Methods: We exposed 11 groups (n=8), of anaesthetized rats to aerosol from propylene glycol (PG), vegetable glycerin (VG), PG+VG without nicotine, a USONICIG Zip ultrasonic vaping device, previous generation e-cigarettes (tank style with freebase nicotine), 5% nicotine JUUL pods of three flavors (Virginia tobacco, Mango, and Menthol), and an IQOS heated tobacco product; with Marlboro Red cigarette smoke and clean air as controls, to a single session of 10 cycles of pulsatile 5s exposure over 5 minutes. Endothelial function was quantified as arterial flow-mediated dilation (FMD) using micro-ultrasound. Results: Aerosol/smoke from all conditions except air significantly impaired FMD (Figure: each colored line denotes one rat, black horizontal bars denote means). The extent of impairment ranged from 40%-67% although there were no significant differences between groups. Nicotine absorption into the blood varied widely from these undiluted aerosols (those containing nicotine), with IQOS being the highest, and USONICIG and previous generation e-cig being the lowest. Conclusions: A single session of exposure to aerosol from a wide range of ENDS, including multiple types of e-cigarettes, a heated tobacco product, and an ultrasonic vaping device, all impair endothelial vascular function comparably to combusted cigarettes. Key words: JUUL, IQOS, ultrasonic vaping device, e-liquids, flow-mediated dilation