Circulating extracellular microvesicles associated with electronic cigarette use increase endothelial cell inflammation and reduce nitric oxide production.

The purpose of this study was to determine the effect of circulating microvesicles isolated from chronic electronic (e-)cigarette users on cultured human umbilical vein endothelial cell (HUVEC) expression of nuclear factor-κB (NF-κB), cellular cytokine release, phosphorylation of endothelial nitric oxide synthase (eNOS) and NO production. The HUVECs were treated with microvesicles isolated via flow cytometry from nine non-tobacco users (five male and four female; 22 ± 2 years of age) and 10 e-cigarette users (six male and four female; 22 ± 2 years of age). Microvesicles from e-cigarette users induced significantly greater release of interleukin-6 (183.4 ± 23.6 vs. 150.6 ± 15.4 pg/mL; P = 0.002) and interleukin-8 (160.0 ± 31.6 vs. 129.4 ± 11.2 pg/mL; P = 0.01), in addition to expression of p-NF-κB p65 (Ser536) (18.8 ± 3.4 vs. 15.6 ± 1.5 a.u.; P = 0.02) from HUVECs compared with microvesicles from non-tobacco users. Nuclear factor-κB p65 was not significantly different between microvesicles from the non-tobacco users and from the e-cigarette users (87.6 ± 8.7 vs. 90.4 ± 24.6 a.u.; P = 0.701). Neither total eNOS (71.4 ± 21.8 vs. 80.4 ± 24.5 a.u.; P = 0.413) nor p-eNOS (Thr495) (229.2 ± 26.5 vs. 222.1 ± 22.7 a.u.; P = 0.542) was significantly different between microvesicle-treated HUVECs from non-tobacco users and e-cigarette users. However, p-eNOS (Ser1177) (28.9 ± 6.2 vs. 45.8 ± 9.0 a.u.; P < 0.001) expression was significantly lower from e-cigarette users compared with non-tobacco users. Nitric oxide production was significantly lower (8.2 ± 0.6 vs. 9.7 ± 0.9 µmol/L; P = 0.001) in HUVECs treated with microvesicles from e-cigarette users compared with microvesicles from non-tobacco users. This study demonstrated increased NF-κB activation and inflammatory cytokine production, in addition to diminished eNOS activity and NO production resulting from e-cigarette use. HIGHLIGHTS: What is the central question of this study? Circulating microvesicles contribute to cardiovascular health and disease via their effects on the vascular endothelium. The impact of electronic (e-)cigarette use on circulating microvesicle phenotype is not well understood. What is the main finding and its importance? Circulating microvesicles from e-cigarette users increase endothelial cell inflammation and impair endothelial nitric oxide production. Endothelial inflammation and diminished nitric oxide bioavailability are central factors underlying endothelial dysfunction and, in turn, cardiovascular disease risk. Deleterious changes in the functional phenotype of circulating microvesicles might contribute to the reported adverse effects of e-cigarette use on cardiovascular health.

Effect of restricting menthol flavored cigarettes or E-cigarettes on smoking behavior in menthol smokers.

Bans of menthol characterizing flavor in tobacco products have been enacted in some localities and proposed in the United States for cigarettes. To gather data regarding how restrictions for menthol in cigarettes and e-cigarettes may affect current menthol cigarette smokers, 37 African American menthol smokers participated in a pilot study in which they were asked to abstain (n = 18) or not abstain from menthol cigarettes (n = 19) for 8-weeks. All participants received menthol flavored e-cigarettes for 4 weeks and tobacco flavored e-cigarettes for 4 weeks in random order. Number of cigarettes smoked per day (estimated mean ratio [EMR] = 0.31; 95% CI: 0.13, 0.72) and exhaled CO concentrations (EMR = 0.61; 95% CI: 0.43, 0.88) were lower in the menthol cigarette abstainer group compared to the menthol cigarette non-abstainer group. Those in the menthol cigarette abstainer group reported higher scores on motivation to quit (p = 0.03) and perceived effectiveness of quitting skills (p = 0.02). There were no substantial effects seen in amount smoked or exhaled CO based on flavor of e-cigarettes provided. Higher e-cigarette use (based on reported puffs per day) was reported in the menthol cigarette abstainer (vs. non-abstainer) group (p < 0.01) and also during the 4-week period when provided with menthol (vs. tobacco) e-cigarettes (p < 0.01). These data suggest that the potential of e-cigarettes to reduce tobacco related harm may be enhanced if combined with a ban on menthol flavor in combustible cigarettes. Larger studies are needed to determine the effect of limiting menthol in e-cigarettes on smoking behavior among current menthol smokers.

Effect on Tobacco Use and Subjective Measures of Including E-cigarettes in a Simulated Ban of Menthol in Combustible Cigarettes.

INTRODUCTION: Bans of menthol characterizing flavor in tobacco products have been proposed; however, there is limited data regarding the impact on current menthol cigarette smokers of including e-cigarettes in such bans. METHODS: In this six-week pilot study, 47 menthol smokers were randomized to receive all tobacco products from an experimental marketplace simulating either no menthol ban, a menthol ban for cigarettes but not e-cigarettes, or a ban for both ("total menthol ban"). RESULTS: At the first visit, all but one participant selected cigarettes with e-cigarettes selected by 38%, 69%, and 40% of participants in the no ban, menthol cigarette ban, and total menthol ban groups, respectively. Over the study period, the total menthol ban group smoked more than the menthol cigarette ban group (estimated mean ratio [EMR] in cigarettes per day = 1.38; 95% CI: 1.1, 1.75; p = .006). Compared to the no ban condition, the menthol cigarette ban group smoked slightly fewer (EMR = 0.87; 95% CI: .68, 1.11) and the total menthol ban group smoked slightly more (EMR = 1.20; 95% CI: 1.00, 1.45) although neither difference reached statistical significance. In both menthol ban conditions, ratings were lower (vs. no ban) on several measures of craving and cigarette effects and liking. CONCLUSIONS: Menthol bans that include e-cigarettes may result in different patterns of tobacco use than if only combustible cigarettes are included, although e-cigarettes were not extensively used in any group. Larger studies are needed to determine policies most likely to provide the largest public health benefit. IMPLICATIONS: Bans of menthol characterizing flavor have been proposed, however, the effects on menthol cigarette smokers of including e-cigarettes in such bans are not clear. This study found that smokers randomized to a simulated ban on menthol in both cigarettes and e-cigarettes smoked more cigarettes per day over the 6-week study period than those randomized to a simulated ban on menthol in only cigarettes suggesting that smoking patterns among current menthol smokers differ depending on which products are included in a menthol ban. Larger studies are needed to determine the policies most likely to provide the largest public health benefit.

Effects on Smoking Behavior of Switching Menthol Smokers to Non-menthol Cigarettes.

INTRODUCTION: Bans of menthol characterizing flavor in cigarettes have been implemented in some localities and have been proposed more broadly. One proposed benefit of such a ban is to increase cessation rates among current menthol smokers. There is currently relatively limited data regarding how smoking behavior changes if menthol smokers switch to non-menthol cigarettes. AIMS AND METHODS: African American menthol smokers interested in quitting smoking were randomized to either continue smoking menthol (n = 60) or switch to non-menthol cigarettes (n = 62) for 1 month prior to a cessation attempt. Cessation results were reported previously; this analysis reports the results from the pre-cessation visits at which amount smoked, exhaled carbon monoxide (CO) concentration, urinary cotinine concentrations, and subjective measures were assessed. RESULTS: Over the 4-week study period, those switching to non-menthol (vs. continuing to smoke menthol) cigarettes smoked fewer cigarettes per day (mean ratio: 0.86; 95% confidence interval [CI]: 0.76, 0.98; p = .02), reported lower withdrawal symptom severity (mean difference -1.29; 95% CI: -2.6 to -0.01; p = .05) and higher perceived effectiveness of their skills for quitting smoking (mean difference 0.56; 95% CI: 0.02-1.10; p = .05). No significant differences were found between groups in exhaled CO, urinary cotinine concentrations, or most other subjective effects including support for a ban on menthol characterizing flavor in cigarettes. CONCLUSIONS: These results suggest that were menthol cigarettes no longer available, those that switch to non-menthol cigarettes would not change their smoking behavior in a way that is likely to be more hazardous, with some indicators suggesting that there may be some benefit.Clinicaltrials.gov # NCT02342327. IMPLICATIONS: A ban on menthol characterizing flavor in cigarettes has been proposed as a potential means by which to increase smoking cessation rates among current menthol cigarette smokers. This study evaluated how African American menthol cigarette smokers adjusted their smoking behavior after switching to non-menthol cigarettes. Although the overall differences between groups were modest, they were in a direction consistent with decreased smoking suggesting that current smokers would not adjust their behavior in a way that is likely to be more hazardous, with some indicators suggesting that there may be some benefits.

Effects on time to lapse of switching menthol smokers to non-menthol cigarettes prior to a cessation attempt: a pilot study.

INTRODUCTION: Menthol smokers (particularly African-Americans) have lower cessation success rates than non-menthol smokers. With bans being considered on characterising menthol flavour in cigarettes, data are needed regarding how switching to non-menthol cigarettes impacts cessation measures. METHODS: In this randomised pilot study, African-American menthol cigarette smokers interested in quitting smoking either continued smoking menthol cigarettes (n=60) or switched to non-menthol cigarettes (n=62) for a 1-month period prior to a cessation attempt. The primary endpoint was time to smoking lapse (ie, time from quitting until any smoking). Additional endpoints included time to smoking relapse (ie, number of days from quitting until the first of seven consecutive smoking days) and difference between groups in subjective measures. RESULTS: After attempting to quit, the non-menthol cigarette group had indications of delayed time to lapse (HR 0.82; 95% CI 0.55 to 1.22; p=0.33) and time to relapse (HR 0.67; 95% CI 0.42 to 1.06; p=0.09), although these were not statistically significant. Post hoc analyses suggest that observed differences were largely due to a smaller proportion of participants in the non-menthol group relapsing within the first day of quitting (21% vs 40%; p=0.05). Values of other measures assessed postcessation were largely similar between groups. CONCLUSIONS: These data suggest that among African-American smokers, a menthol cigarette ban would not undermine short-term cessation measures and may result in some benefits. Future research is needed to assess longer term cessation rates and to identify interventions to maximise cessation success in the event of a menthol ban. TRIAL REGISTRATION NUMBER: NCT02342327.

Endothelial-derived extracellular vesicles associated with electronic cigarette use impair cerebral microvascular cell function.

The aim of this study was to determine the effect of circulating endothelial cell-derived microvesicles (EMVs) isolated from e-cigarette users on human cerebral microvascular endothelial cells (hCMECs) nitric oxide (NO) and endothelin (ET)-1 production and tissue-type plasminogen activator (t-PA) release. Circulating EMVs (CD144-PE) were isolated (flow cytometry) from 27 young adults (19-25 yr): 10 nonsmokers (6 M/4 F), 10 e-cigarette users (6 M/4 F), and 7 tobacco cigarette smokers (4 M/3 F). hCMECs were cultured and treated with isolated EMVs for 24 h. EMVs from e-cigarette users and cigarette smokers induced significantly higher expression of p-eNOS (Thr495; 28.4 ± 4.6 vs. 29.1 ± 2.8 vs. 22.9 ± 3.8 AU), Big ET-1 (138.8 ± 19.0 vs. 141.7 ± 19.1 vs. 90.3 ± 18.8 AU) and endothelin converting enzyme (107.6 ± 10.1 and 113.5 ± 11.8 vs. 86.5 ± 13.2 AU), and significantly lower expression of p-eNOS (Ser1177; 7.4 ± 1.7 vs. 6.5 ± 0.5 vs. 9.7 ± 1.6 AU) in hCMECs than EMVs from nonsmokers. NO production was significantly lower and ET-1 production was significantly higher in hCMECs treated with EMVs from e-cigarette (5.7 ± 0.8 µmol/L; 33.1 ± 2.9 pg/mL) and cigarette smokers (6.3 ± 0.7 µmol/L; 32.1 ± 3.9 pg/mL) than EMVs from nonsmokers (7.6 ± 1.2 µmol/L; 27.9 ± 3.1 pg/mL). t-PA release in response to thrombin was significantly lower in hCMECs treated with EMVs from e-cigarette users (from 38.8 ± 6.3 to 37.4 ± 8.3 pg/mL) and cigarette smokers (31.5 ± 5.5 to 34.6 ± 8.4 pg/mL) than EMVs from nonsmokers (38.9 ± 4.3 to 48.4 ± 7.9 pg/mL). There were no significant differences in NO, ET-1, or t-PA protein expression or production in hCMECs treated with EMVs from e-cigarette users and smokers. Circulating EMVs associated with e-cigarette use adversely affects brain microvascular endothelial cells and may contribute to reported cerebrovascular dysfunction with e-cigarette use.NEW & NOTEWORTHY In the present study, we determined the effect of circulating endothelial cell-derived microvesicles (EMVs) isolated from e-cigarette users on human cerebral microvascular endothelial cells (hCMECs) nitric oxide (NO) and endothelin (ET)-1 production and tissue-type plasminogen activator (t-PA) release. EMVs from e-cigarette users reduced brain microvascular endothelial cell NO production, enhanced ET-1 production, and impaired endothelial t-PA release. EMVs are a potential mediating factor in the increased risk of stroke associated with e-cigarette use.

Effect of nicotine lozenge use prior to smoking cue presentation on craving and withdrawal symptom severity.

BACKGROUND: Smokers are often advised to use nicotine lozenge after cravings or withdrawal symptoms are present, which may be too late to prevent lapses. This study assesses if lozenge use prior to smoking cue exposure attenuates cue-induced increases in symptom severity. METHODS: In this randomized, cross-over study, participants completed three laboratory sessions at which they proceeded through 4 "rooms" in a virtual reality environment. The first and last "rooms" contained neutral cues and the others contained smoking cues. At one session, a 4 mg nicotine lozenge was not given until after cue exposure (to approximate current use: i.e., after craving and withdrawal symptoms occur). At the other two sessions either a nicotine or placebo lozenge was used 15 min before cue exposure procedures. Craving and withdrawal symptoms were measured throughout each laboratory session. RESULTS: Of 58 participants randomized; 40 completed all 3 labs. Absolute levels of craving and withdrawal symptom severity during cue exposure were lower when placebo or active lozenge was used prior to cue presentation procedures vs. no treatment until after cue presentation procedures (all p-values <0.05). There were no differences among conditions in the magnitude of symptom severity increase occurring between the first neutral room and the cue rooms. CONCLUSIONS: Lozenge use prior to cue exposure may minimize cue induced symptom severity but when taken 15 min prior to cues the decrease is not different than placebo. Research is needed to determine if another time-frame relative to cue exposure would be more effective.