E-cigarettes and DNA damage

Researchers report the DNA-damaging potential of E-cigarette smoke (ECS). E-cigarettes deliver nicotine as an aerosol without burning tobacco, and therefore avoid the carcinogenic byproducts of tobacco curing and combustion. E-cigarettes are marketed as a safer alternative to smoking tobacco.

Moon-shong Tang and colleagues found that mice exposed to ECS had higher levels of DNA damage in the heart, lungs, and bladder, compared with control mice exposed to filtered air. Mice exposed to ECS also had reduced DNA repair activity and lower levels of certain DNA repair proteins in the lungs relative to control mice. Similar effects were observed in cultured human lung and bladder cells exposed to nicotine and nicotine-derived nitrosamine ketone (NNK), a carcinogenic nicotine derivative. Cultured human cells exposed to nicotine and NNK also had higher rates of mutation and tumorigenic transformation than control cells.

The results suggest that nicotine nitrosation can occur in certain human and mouse tissues, and that the resulting products are further metabolized into DNA-damaging compounds. Thus, although ECS has fewer carcinogens than tobacco smoke, E-cigarette smokers might have a higher risk than nonsmokers of developing lung and bladder cancers and heart diseases, according to the authors.

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