Abstract 11779: E-cigarette Nicotine Vapor Increases Aortic Stiffness in Mice

Abstract

Introduction: Arterial stiffness is increased by smoking and is a risk factor for various cardiovascular diseases. In recent years electronic cigarettes (e-cigs) have gained worldwide popularity as potentially “healthier” substitutes for conventional smoking, especially among young adults and teenagers. These devices provide nicotine at levels equal to or greater than those from conventional cigarettes. To date, little is known about the effects of e-cigs on vasculature. We investigated whether inhaled nicotine through e-cig vapor leads to enhanced aortic stiffening through extracellular matrix remodeling in both young and adult mice. Hypothesis: Inhalation of nicotine vapor augments aortic stiffening process when compared to e-juice only or room air. Methods: Young (6-week-old) and adult (14-week-old) male C57BL/6J mice were exposed to unflavored e-cig vapor with or without nicotine (24 mg/ml) at 9 puffs/min for 1 hour/day for 21 consecutive days, or room air. In vivo aortic stiffness was assessed by measurement of pulse wave velocity. At the end of the time-course the aorta was explanted for segmental pressure myographic measurements. Blood pressure and pulse rate were tracked throughout the experiment utilizing a non-invasive tail-cuff-system. A subset of aortic tissue was also subjected to exploratory transcriptional profiling. Results: Exposure to e-cig vapor containing nicotine significantly augmented aortic stiffness when compared to room air or e-juice only exposed mice. This was apparent in both pulse wave velocity measurements and pressure myography. Observed effects were more pronounced in young mice when compared to adult animals, and occurred in both the thoracic and abdominal aortic segments. Expression array data identified changes between the groups. There were no significant differences between room air-exposed mice and mice exposed to e-juice without nicotine. Conclusion: Inhaled e-cig nicotine significantly increased murine aortic stiffness in both aortic segments after three weeks of daily exposure, especially in younger mice. Further clinical investigations into the direct effects of nicotine e-cigarettes on human vasculature, especially in young people, are warranted to contextualize these results.