Current perspective on e-cigarette use and respiratory variables: mechanisms and messaging

Figures & data

Table 1 Studies of Oxidative Stress and Inflammation

Study	Type	Exposure^A	Assay(s)	Main finding(s)	DNA damage
Scott 2018 [49]	In vitro (cells)	Aerosol (vaped or nonvaped)	Cell viability, IL-6, TNFα, MMP-9, phagocytosis	Viability reduced by vaped e-liquid Inflammatory factors ↑, phagocytosis ability ↓ in vaped condition	n.a.
Muthu- malage 2019 [50]	In vitro (Cells, 2 lines)	Aerosol (JUUL)	IL2, IL-8 Prostaglandin E2 ROS	Inflammatory factors ↑Oxidative stress	Yes
Sun 2021 [45]	In vivo (mice)	Aerosol (PG, G), TS	Fibronectin, CRP 8-oxodG	↑Inflammatory factors ↑Oxidative stress	Yes
Ma (2020) [43]	In vitro (cells), In vivo (mice)	Aerosol	IL-1b, IL-8, TNFα, ROS	Pro-inflammatory effect on different cell lines, evidence of oxidative stress. Heating e-liquid ↑oxidative stress.	n.a.
Roxlau 2022 [41]	In vitro (cell lines, in vivo (mice)	Aerosol	IL-5.IL-13, IL-16, MMP9, MMP12	↑ inflammatory changes for in vitro study. E-cig exposure caused structural alterations consistent with emphysema.	n.a.
Moshensky 2022 [52]	In vivo (mice)	Aerosol	IL-1β, IL-6, IL-8, TNFα	↑ Inflammatory gene expression. Changes noted in brain, lung, GI tract suggestive of ↑ inflammation, ↓ innate immunity.	n.a.
Rodriguez 2022 [57]	In vivo (mice)	Aerosol (e-cig, TS)	IL-6, IL-15, MMP-9, TBARS	↑proinflammatory cytokines, cell damage ↑ density of alveolar air space (∼emphysema) in e-cig group.	n.a.
Been 2022 [59]	In vivo (mice) vehicle)	Aerosol (e-cig,	IL-4, IL-10, IL-13, TNFα, 8-OHdG, Sod2, Nrf2	Significant ↑in proinflammatory cytokines and oxidative stress. for e-cig condition. Also observed ↑in antioxidants.	Yes
Song 2020 [61]	In vivo (Human)	Exptl (e-cig, ∼e-cig)	IL-8, IL-13, TNFα	E-cig use frequency correlated with levels of pro-inflammatory cytokines	n.a.
Tommasi (2022) [64]	In vivo (Humans)	Natural (smoker, vaper)	Gene expression (RNA-seq)	Small overlap between gene expression for smokers, vapers. Most common gene pathways involved inflammation, innate immunity)	Yes
Wetherill 2022 [65]	In vivo (humans)	Natural (smoker, vaper)	PET lung imaging (iNOS), IL-6, TNFα	E-cig users had more iNOS inflammation compared with controls and smokers. IL-6 level correlated with vaping frequency.	n.a.
Kelesidis (2021) [66]	In vivo (human)	Exptl (1 vape session)	Immune cells, neutrophils	Significant ↑in oxidative stress observed after 1 vaping session.	n.a.

Note. IL = interleukin; TNF = tumor necrosis factor; MMP = metalloprotease; ROS = reactive oxygen species; CRP = C-reactive protein; PG = propylene glycol; G = vegetable glycerin; TS = tobacco smoke; Exptl = experimental.

Scott A, Lugg ST, Aldridge K, et al. Pro-inflammatory effects of e-cigarette vapor condensate on human alveolar macrophages. Thorax 2018; 73: 1161–1169.

 PubMed Web of Science ®Google Scholar

Muthumalage T, Lamb T, Friedman MR, et al. E-cigarette flavored pods induce inflammation, epithelial barrier dysfunction, and DNA damage in lung epithelial cells and monocytes. Sci Rep. 2019; 9: 19035. 10.1038/s41598-019-51643-6 1

 PubMedGoogle Scholar

Sun YW, Chen KM, Atkins H, et al. Effects of e-cigarette aerosols with varying levels of nicotine on biomarkers of oxidative stress and inflammation in mice. Chem Res Toxicol. 2021;34(4):1161–1168. doi: 10.1021/acs.chemrestox.1c00033

 PubMed Web of Science ®Google Scholar

Ma T, Wang X, Li L, et al. Electronic cigarette aerosols induce oxidative stress-dependent cell death and NF-κB mediated acute lung inflammation in mice. Arch Toxicol. 2021;95(1):195–205. doi: 10.1007/s00204-020-02920-1

 PubMed Web of Science ®Google Scholar

Roxlau ET, Pak O, Hadzic S, et al. Nicotine promotes e-cigarette vapour-induced lung inflammation and structural alterations. Eur Respir J. 2023;61(6):2200951. doi: 10.1183/13993003.00951-2022

 PubMedGoogle Scholar

Moshensky A, Brand CS, Alhaddad H, et al. Effects of mango and mint pod-based e-cigarette aerosol inhalation on inflammatory states of the brain, lung, heart, and colon in mice. Elife 2022;:e67621. 11 10.7554/eLife.67621

 PubMedGoogle Scholar

Rodriguez-Herrera AJ, Souza ABF, Castro T, et al. Long-term e-cigarette aerosol exposure causes pulmonary emphysema in adult female and male mice. Regul Toxicol Pharmacol. 2023;142:105412. doi: 10.1016/j.yrtph.2023.105412

 PubMedGoogle Scholar

Been T, Traboulsi H, Paoli S, et al. Differential impact of JUUL flavors on pulmonary immune modulation and oxidative stress responses in male and female mice. Arch Toxicol. 2022;96(6):1783–1798. doi: 10.1007/s00204-022-03269-3

 PubMed Web of Science ®Google Scholar

Song M-A, Reisinger SA, Freudenheim JL, et al., Effects of electronic cigarette constituents on the human lung: A pilot clinical trial. Cancer Prev Res. 2020; 13: 145–152.

 PubMed Web of Science ®Google Scholar

Tommasi S, Caliri AW, Caceres A, et al. Deregulation of biologically significant genes and associated molecular pathways in the oral epithelium of electronic cigarette users. Int J Mol Sci. 2019;20(3):738. doi: 10.3390/ijms20030738

 PubMed Web of Science ®Google Scholar

Wetherill JR, Door RK, Young AJ, et al. Molecular imaging of pulmonary inflammation in users of electronic and combustible cigarettes: A pilot study. J Nuclear Med. 2023; 64: 787–602.

 Google Scholar

Kelesidis T, Tran E, Nguyen R, et al. Association of one vaping cession with cellular oxidative stress in otherwise healthy young people with no history of smoking or vaping: a randomized clinical crossover trial JAMA Pediatrics. 2021; 175: 1174–1176.

 Google Scholar