Table 4.

Summary of Solution-Based Electronic Cigarette Aerosol Studies.

Reference	Cells	eCVE Preparation	Results
Romegna et al. [161]	BALB/3T3 fibroblasts (mouse)	200 mg e-liquid extracted into 20 mL culture medium	One of 21 extracts was cytotoxic (51% viability) at highest (undiluted concentration); all others not cytotoxic
Cervellati et al. [158]	A549	Whole smoke delivered to incubator with lids of culture plate removed	Flavored e-liquids and e-liquids with nicotine led to decreased in viability (LDH)
Higham et al. [157]	Neutrophils isolated from peripheral donor blood	50–300 mL aerosol bubbled through RPMI 1640 culture medium (volume unspecified). Normalized to OD at 320 nm in culture medium. 0.22 micron filtered	Increase in MMP-9 and IL-8 release with exposure to eCVE
Putzhammer et al. [159]	HUVEC	88.5 mg liquid (equivalent to 700 mL aerosol) extracted into 8 mL culture medium. 0.2 micron filtered. Prepared freshly prior to experiments	Some e-liquid aerosols decreased viability, one of 11 tested increased oxidative stress. Results were liquid dependent. The same electronic cigarettes were used with different liquids; authors isolated effects to liquids.
Taylor et al. [162]	NCI-H292	550 mL aerosol bubbled through 20 mL DMEM/F12. Nicotine content characterized by GC-MS, tar by OD at 320 nm	No cytotoxic effects or oxidative stress induced by eCVE
Leslie et al. [156]	BEAS-2 B, IB3-1, C38 (human bronchial epithelium cell lines), Wi-38 fibroblasts, J774 THP-1 macrophages	490 mL aerosol extracted into 10 mL DMEM/F12, EMEM, or RPMI 1640. Used within 1 h	Some extracts reduced viability below 70% (considered cytotoxic), varied depending on flavor and cell line
Taylor et al. [163]	HUVEC	550 mL aerosol extracted into 20 mL Vasculife culture medium. Nicotine concentration qualified via GC-MS	eCVE did not inhibit endothelial cell migration
Bengalli et al. [160]	A549, NCI H441	11 L aerosol extracted into 25 mL OPTIMEM culture medium, 0.2 micron filtered and frozen at −20 until use	Viability and barrier integrity decreased with exposure to certain flavors, one of which led to an increase in IL-8 and MCP-1 release. Unflavored liquids produced insignificant effects. Nicotine was not found to be a factor.
Higham et al. [136]	Calu-3, primary bronchial epithelial cells (from healthy and COPD patients). Cultured at ALI but exposed to liquid solution.	50–300 mL aerosol bubbled through DMEM/F12 culture medium (volume unspecified). Normalized to OD at 320 nm in culture medium. 0.22 micron filtered	eCVE had cytotoxic effects and increased IL-6 and IL-8 while decreasing TEER, indicating a decrease in barrier integrity