In vitro sex-dependent effects of e-cigarettes in human dermal microvascular endothelial cells
Authors: Meister Maureen , Wong Brett , Feresin Rafaela 
Published: May 2023

Introduction: Electronic cigarettes (e-cigarettes) are often considered a healthier alternative to traditional cigarettes. However, e-cigarettes induce systemic oxidative stress and reduce concentrations of nitric oxide (NO) metabolites, both of which can lead to the development of cardiovascular pathologies. Given the inherent differences in cardiovascular disease (CVD) prevalence between sexes, it is important to investigate whether there are divergent responses to e-cigarettes in males and females. Hypothesis: We hypothesized that male- and female-derived cells will differ in their molecular response to e-cigarette condensate treatment. Methods: Male- and female-derived human dermal microvascular endothelial cells (HMVECs) were treated with 0.5% e-cigarette condensate for 24 h. Following treatment, intracellular superoxide (O2-) and NO bioavailability were measured fluorometrically. Protein expression of markers of endothelial health were measured by western blot. Results were analyzed by t-tests within each sex. Results: Data are represented as mean ± standard deviation in arbitrary units. Treatment with e-cigarette condensate increased intracellular O2- (0.04 ± 0.02 vs. 0.07 ± 0.02; p=0.07) and NO (8.89 ± 2.50 vs. 5.36 ± 1.29; p=0.004) in male HMVECs. Interestingly female-derived HMVECs exhibited no change in intracellular O2- or NO following treatment. At the protein level, expression of phosphorylated endothelial nitric oxide synthase (p-eNOSser1177), a key regulatory site for NO production, was increased in male-derived HMVECs treated with e-cigarette condensate (0.029 ± 0.003 vs. 0.019 ± 0.008; p=0.05) but significantly decreased in female-derived HMVECs (0.016 ± 0.002 vs. 0.034 ± 0.008; p=0.01). Conversely, cytoprotective responses appeared to be more prominent in female HMVECs with increased expression of NAD(P)H quinone dehydrogenase (NQO)1 in HMVECs treated with e-cigarette condensate compared to control. Heme oxygenase (HO)-1 was increased in response to e-cigarette condensate treatment in both male- and female-derived HMVECs (2.50 ± 0.17 vs. 1.16 ± 0.24; p=0.001 and (2.36 ± 0.29 vs. 1.27 ± 0.00; p=0.003, respectively). Conclusions: These results point to differential changes at the cellular level in response to e-cigarette condensate treatment. These data suggest, in vitro, there may be sex-dependent mechanistic differences in response to e-cigarettes. Further in vivo investigation is needed to better understand sex-dependent effects of e-cigarette use on the vasculature to evaluate how the use of these devices may contribute to CVD. This work is supported in part by the Agriculture and Food Research Initiative (grant no. 2019-67017-29257/project accession no. 1018642 & grant no.2020-09946/project accession no. 1026389) from the USDA National Institute of Food and Agriculture as well as R01 HL141205 from the National Institutes of Health. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.