Table 1.
In vitro models of e-cigarette pulmonary toxicity
| Study | Cell Type | Exposure Method | Exposure Type | Key Findings |
|---|---|---|---|---|
| Wu et al. (137) | Airway epithelial cells (primary) | Submersion culture | Media diluted e-liquid | No effects on cell viability; increased viral loads after rhinovirus infection; decreased antimicrobial activity |
| Sherwood and Boitano (113) | HBEC (immortalized) | Submersion culture | Media diluted flavoring agents | High concentrations caused cell death; lower concentrations altered membrane ion conductance (via cystic fibrosis transmembrane conductance regulator ion channel, CFTR) |
| Schweitzer et al. (110) | Lung endothelial cells (primary) | Submersion culture | Media diluted e-cig aerosol condensate | Decreased cell proliferation; diminished lung endothelial barrier function; involvement of both nicotine and other e-cig aerosol chemicals |
| Gerloff et al. (50) | Beas2B, H292, HFL1, 16-HBE | Submersion culture | Flavoring compounds and nicotine dissolved in culture media | Many tested compounds increased release of the inflammatory cytokine IL-8, although responses were cell line specific |
| Aug et al. (10) | HBEC (primary) | Air-liquid interface | Media diluted e-liquid | Increased levels of cellular stress; metabolome effects similar to CS exposure |
| Scheffler et al. (108) | HBEC (primary) | Air-liquid interface | E-cig aerosols | Increased oxidative stress; reduced cell viability |
| Garcia-Arcos et al. (46) | HBEC (primary) | Air-liquid interface | E-cig aerosols | No effects on cell viability; nicotine-dependent reduction in ciliary beat frequency and CFTR ion conductance |
| Leigh et al. (76) | H292 | Air-liquid interface | E-cig aerosols | Toxicity measured by viability, metabolic activity and inflammatory cytokine release was device dependent and was increased with higher voltages and flavoring compounds |
| Neilson et al.* (101) | HBEC (primary) | Epi-Airway 3-D model | E-cig aerosols | No effects on cell viability; increased particle deposition compared with CS |
| Hwang et al. (62) | A549 | Submersion culture | Media diluted e-cig aerosol extract; e-cig aerosols | Significant cell death with exposure; decreased antimicrobial activity of macrophages and neutrophils; increased virulence of MRSA |
| Misra et al.* (97) | A549 | Submersion culture | Media diluted e-liquid; pad collected aerosol | Absence of cytotoxicity or inflammatory response; no effects on cell viability; no mutagenic or genotoxic effects |
| Cervellati et al. (26) | A549 | Submersion culture | E-cig aerosols | Increased markers of cytotoxicity; decreased cell viability; changes in cell morphology (vacuolization) |
| Husari et al. (61) | A549 | Submersion culture | Media diluted e-cig aerosol condensate | Increased cell death with high nicotine levels |
HBEC, human bronchial epithelial cells; CS, cigarette smoke; e-cig, electronic cigarette; MRSA, methicillin-resistant Staphylococcus aureus.
*
Studies reporting fundings from the tobacco industry.