Nicotine Does Not Influence Arterial Lipid Deposits in Rabbits Exposed to Second-Hand Smoke

Abstract

Background Second-hand smoke (SHS) accelerates atherogenesis and impairs vascular function. The role of nicotine in this process has not been defined. Methods and Results To examine the potential effects of nicotine on atherogenesis and vascular function, 48 rabbits receiving a 0.5% cholesterol diet were randomized to control (cholesterol diet only), SHS from nicotine-standard research cigarettes (SHS-ST), and SHS from nicotine-free research cigarettes (SHS-NF). The SHS rabbits were exposed to 48 nicotine-standard (12 animals) or nicotine-free (12 animals) cigarettes/d, 5 d/wk for 10 weeks. Air carbon monoxide and particulates and plasma carboxyhemoglobin were significantly higher in the 2 SHS groups than the control group ( P <0.001). The SHS-ST group had significant increases in plasma nicotine and cotinine compared with the other groups ( P <0.001). There was no difference in serum lipids. Lipid lesions were increased in both SHS groups (54±5% [SEM] aorta and 66±4% pulmonary artery, 53±7% and 69±4%, and 39±4% and 43±3% in the SHS-ST, SHS-NF, and control groups, respectively; P =0.049 aorta and P <0.001 pulmonary artery). Conclusions SHS exposure increased arterial lipid lesions, but nicotine did not contribute significantly to this effect. This effect is presumably due to other combustion products in the smoke.