Background: Electronic cigarettes (e-cigarettes) are battery-powered devices heating a liquid (e-liquid) composed of propylene glycol and/or vegetable glycerin, and most commonly, nicotine to form an aerosol (vapor) that is inhaled (i.e. "vaped"). Scarce and conflicting data are available regarding the cardiovascular toxicity of e-cigarettes. We wish to determine the acute effects of propylene glycol/vegetable glycerin and nicotine vaporization at high temperature in comparison to tobacco cigarette smoking on several advanced cardiovascular parameters in healthy chronic e-cigarettes users and tobacco smokers. Furthermore, a large range of plasma, urine and respiratory oxidative stress markers will be quantified. By this way, we aim to demonstrate that e-cigarettes-induced systemic oxidative stress could be linked to cardiovascular toxicity. To the best of our knowledge, this is the first project that evaluates the effects of e-cigarettes vaping in comparison to tobacco cigarette smoking on the cardiovascular system in relation to vaporization temperature, nicotine delivery and oxidative stress.

Aims of the study: This study tests the following hypotheses: 1) acute high temperature vaporization of propylene glycol and vegetable glycerin has no deleterious effects on cardiovascular parameters in comparison to tobacco smoking; 2) Tobacco smoking rises plasma and urine oxidative stress biomarkers. On the contrary, acute and chronic e-cigarettes vaping don't rise these biomarkers. At a cellular level, plasma of smokers but not vapers increases superoxide anion production.

Inclusion Criteria:

• Healthy subjects

Exclusion Criteria:

• Any form of cardiovascular disease
• Any form of pulmonary disease like asthma or COPD
• Any form of systemic or chronic disorder
• Active allergy within 4 weeks of the study
• Symptoms of infection or inflammation within 4 weeks of the study
• Pregnancy