Abstract 16844: Relative Endothelial Toxicity of Tobacco Smoke and E-Cigarette Aerosol: A Functional and Mechanistic Assessment

• Published in: Circulation (New York, N.Y.) Vol. 138; no. Suppl_1 Suppl 1; p. A16844
• Main Authors: Mohammadi, Leila, Derakhshandeh, Ronak, Han, Daniel D, Whitlatch, Adam, Huang, Abel, Schick, Suzaynn F, Springer, Matthew L
• Format: Journal Article
• Language: English
• Published: by the American College of Cardiology Foundation and the American Heart Association, Inc 06.11.2018
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.138.suppl_1.16844

BackgroundSmoking cigarettes decreases expression of eNOS in the endothelium, resulting in lower nitric oxide (NO) secretion and decreased flow-mediated dilation in the conducting arteries. In contrast, the effects of e-cigarettes (e-cigs) on endothelial function are just beginning to be studied and the mechanisms of action are unclear.AimTo test the hypothesis that circulating factors from e-cigarette users decrease endothelial eNOS protein levels and NO secretion in primary endothelial cell cultures, relative to nonsmokers and cigarette smokers.Methods36 healthy individuals were recruited and grouped as nonsmokers (n=12), cigarette smokers (n=7), and e-cig users (n=17). Human umbilical vein endothelial cells (HUVECs) were cultured at 20,000 cells per well in 24-well culture plate. Serum samples from individual subjects and endothelial growth media were added at a 1:1 ratio to confluent cells and incubated for 12 hours (basal condition), followed by fresh medium containing VEGF at 50 ng/ml for 30 min (stimulated condition). The amount of NO liberated from cells was measured in culture supernatants by the chemilumin- escence method using a NO analyzer. Endothelial NO synthase (eNOS) protein levels in HUVECs was measured in cell lysates by ELISA. NO and eNOS results were normalized to cell number.ResultsThe cells treated with serum from e-cig users vs. nonsmokers produced less NO upon stimulation (P<.03) and contained less eNOS protein (P<.03). eNOS protein level was lower in the e-cig user serum group than in the cigarette smoker serum group (P<.05), although stimulated NO production was decreased less by e-cig user serum than by smoker serum. Lower eNOS levels in the cigarette group vs. non-smoker group was not significant, but stimulated NO was significantly lower in the cigarette group vs. nonsmoker (P<.006; see figure).ConclusionExposure of cultured endothelial cells to circulating factors from e-cig users, relative to non-users, leads to lower eNOS protein levels and decreased NO production.