Toxicological Aspects Associated with Consumption from Electronic Nicotine Delivery System (ENDS): Focus on Heavy Metals Exposure and Cancer Risk

Abstract

Tobacco smoking remains one of the leading causes of premature death worldwide. Electronic Nicotine Delivery Systems (ENDSs) are proposed as a tool for smoking cessation. In the last few years, a growing number of different types of ENDSs were launched onto the market. Despite the manufacturing differences, ENDSs can be classified as “liquid e-cigarettes” (e-cigs) equipped with an atomizer that vaporizes a liquid composed of vegetable glycerin (VG), polypropylene glycol (PG), and nicotine, with the possible addition of flavorings; otherwise, the “heated tobacco products” (HTPs) heat tobacco sticks through contact with an electronic heating metal element. The presence of some metals in the heating systems, as well as in solder joints, involves the possibility that heavy metal ions can move from these components to the liquid, or they can be adsorbed into the tobacco stick from the heating blade in the case of HTPs. Recent evidence has indicated the presence of heavy metals in the refill liquids and in the mainstream such as arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu), and lead (Pb). The present review discusses the toxicological aspects associated with the exposition of heavy metals by consumption from ENDSs, focusing on metal carcinogenesis risk.

Unburned Tobacco Smoke Affects Neuroinflammation-Related Pathways in the Rat Mesolimbic System

“…This brand-new system heats rather than burns tobacco to create mainstream smoke that the user inhales. Despite these products having been promoted as a substitute for traditional cigarette smoking, until now, this solution has not proven to be optimal; HnB devices may increase the risk of dual or poly-tobacco product use among young adults, including current exclusive e-cigarette users [5][6][7]. Despite the amount of nicotine in HnB devices being quite similar to the mean nicotine quantity reported for conventional combustible cigarettes, smokers who try to switch to HnB devices to quit smoking have reported experiencing withdrawal symptoms from traditional cigarettes and cravings for them, often leading to dual use [8,9].…”