Lung Damage Caused by heated Tobacco Products and Electronic Nicotine Delivery Systems: a Systematic Review.

Introduction:
This summary will provide an overview of a systematic review of studies on the adverse effects of heated tobacco products (hTPs) and electronic nicotine delivery systems (ENDS) on the respiratory system. The review includes 79 studies without conflict of interest and provides evidence that these devices cause lung damage through various mechanisms.

Key Points:

* The review includes 79 studies, mostly in vitro, animal models, and human studies.
* hTPs and ENDS produce damage in the respiratory system through mechanisms previously reported in conventional cigarettes and new mechanisms specific to these devices.
* The devices increase the levels of pro-inflammatory and inflammatory markers, such as IL-6, IL-8, IL-13, IFN-γ, MMP-9, and IL-1β, and lower levels of CXCL1, RaGE, and GM-CSF.
* Exposure to e-cigarette aerosols induces epithelial barrier dysfunction, impairs repair mechanisms, and increases the risk of carcinogenesis.
* The use of hTPs and ENDS reduces endothelial function and increases serum markers of inflammation and oxidative stress.
* The devices alter innate defense and lung structure, and their use is associated with clinical consequences such as severe tracheomalacia, lipid deposits in the tissue, and EVaLI (e-cigarette or vaping product use-associated lung injury).
* The majority of EVaLI patients were healthy adolescents and young adults who had smoked e-liquids containing ThC and nicotine exclusively.

Main Message:
The systematic review provides significant evidence that hTPs and ENDS are an emerging public health problem and should be regulated or avoided. The devices produce lung damage through various mechanisms, some of which are specific to these devices. The use of these devices is associated with clinical consequences, including EVaLI, and increases the risk of carcinogenesis. Therefore, primary-contact physicians and experts in the field should not recommend these devices as nicotine replacement therapy to smokers, especially those with chronic respiratory diseases like COPD and asthma.

Bravo-Gutiérrez Oa, Falfán-Valencia R, Ramírez-Venegas a, Sansores Rh, Ponciano-Rodríguez G, Pérez-Rubio G. Lung Damage Caused by heated Tobacco Products and Electronic Nicotine Delivery Systems: a Systematic Review. International journal of environmental research and public health. 2021;18(8). doi:10.3390/ijerph18084079