Figure 6.

E-cigarette alters the inflammatory response of circulating human monocytes. Inflammatory markers TNFα (A–C), IL-6 (D–F), and IL-8 (G–I) were obtained from circulating monocytes in nonsmoking nonvaping healthy controls (black) and from e-cigarette users at baseline (red) and after 2 wk of reduced e-cigarette usage (blue). This figure is further separated into cytokines secreted under unstimulated conditions (A, D, and G) and LPS-stimulated conditions (B, E, and H). Normalized TNFα (C), IL-6 (F), and IL-8 (I) were calculated by dividing cytokine levels from LPS-stimulated monocytes by cytokine levels from nonstimulated monocytes from each subject. Paired lines between e-cigarette and reduced use represent paired changes in cytokine levels from the same subject in the setting of reducing use of e-cigarettes. Error bars represent the means ± SD. *P < 0.05, **P < 0.01, and ***P < 0.001, as determined by Student’s t test. LPS, lipopolysaccharide.