CORESTA Congress, New Orleans, 2002, STPOST 05
Changes in free levels of oxidative DNA damage/repair products in the alveolar fluid of smokers after switching to Eclipse, a cigarette that primarily heats rather than burns tobacco
R.J. Reynolds Tobacco Company, Winston Salem, NC, USA
Oxidative DNA damage has been implicated in aging, carcinogenesis, heart disease, and neurodegenerative diseases. 8-Hydroxy-2'-deoxyguanosine (8-OHdG) is a principal stable marker of hydroxyl radical damage to DNA. Tobacco smoking has been shown to increase the levels of oxidative DNA damage rate by 35-50% as estimated from the urinary excretion of 8-OHdG, and the level of 8-OHdG in leukocytes by 20-50%. Recent studies in our laboratory showed no statistically significant differences in levels of urinary 8-OHdG in smokers and nonsmokers when both groups maintained exactly the same diets for 3 weeks. To determine if smokers switching to a reduced risk cigarette product such as Eclipse, a more robust approach was needed. Bronchial alveolar fluid was obtained from smokers at baseline, that is, before switching to Eclipse. After 12 weeks of smoking Eclipse cigarettes only, bronchial alveolar fluid was obtained again. The alveolar fluid was analyzed for levels of 8-OHdG and the decreases were on average 64% from initial levels. Urine and plasma levels of 8-OHdG decreased but not statistically significantly. The data indicate that there is a significant decreased local respiratory tract DNA oxidative damage rate from Eclipse. The overall whole body load or output of DNA damage products is sufficiently variable among individuals to mask the significance of the decrease in peripheral samples.