E-Cigarettes and Coronary Endothelial Function in Dual Users

The increasing popularity and evolving technology of electronic cigarettes (e-cigarettes) have outpaced the scientific research needed to propose evidence-based regulation. The greatest increase in use of e-cigarettes, by far, is by young adult cigarette smokers—dual users—who endorse marketing claims that these products are safe and help them cut down on their cigarette tobacco smoking. Given the potent toxicity of cigarettes on the heart and blood vessels, it is very important to determine if the safety claims about e-cigarettes are true. Regular cigarette smoke contains fine particles, created from burning the cigarette, that enter the body through the lungs and damage blood vessel function leading to heart disease. Though the exposure to toxins is far less with e-cigarettes, they still deliver nicotine vapor which contains unknown particles that may damage blood vessels. While cigarette smoking is well known to impair the regulation of blood flow in the heart the comparative effect of e-cigarettes has not been previously studied. Because the effect of the particles produced by e-cigarettes on blood vessel function is unknown, we will use advanced cardiac ultrasound, combined with handgrip exercise to evaluate the effect of nicotine free and high nicotine electronic cigarette liquid on blood flow regulation. Subjects will also have heart blood vessel function evaluated before and immediately after smoking a regular cigarette. To determine if reduced nitric oxide (a molecule that relaxes blood vessels) is the reason for the reduced blood flow regulation cause by cigarettes and e-cigarettes, we will ascertain if L-arginine (a molecule that replenishes nitric oxide) will reverse the reduced blood flow regulation. The results of this study will fill in large gaps in our understanding of the acute effects of e-cigarettes on blood flow regulation in the heart and in so doing inform currently debated California and national policy decision about the regulation of e-cigarettes. In addition the results will generate exciting information to capture additional funding to further study the mechanisms by which e-cigarettes impair blood flow regulation in the heart.