Benzo[ a]pyrene diol-epoxide DNA adducts and levels of polycyclic aromatic hydrocarbons in autoptic samples from human lungs

Abstract

Benzo[ a]pyrene (BaP) and other polycyclic aromatic hydrocarbons (PAHs) which are present in cigarette smoke, are common air and food genotoxic contaminants and possible human carcinogens. We measured the following PAH levels: benzo[ a]anthracene, benzo[ b]fluoranthene, benzo[ k]fluoranthene, BaP, dibenzo[ a, h]anthracene, benzo[ g, h, i]perylene as well as (±) syn and anti BaP diol-epoxide (BPDE) DNA adducts in autopsy samples from the lungs of non-smokers, ex-smokers and smokers who had lived in Florence, Italy. PAH levels in lung tissue were similar in all groups, with the exception of dibenzo[ a, h]anthracene (DBA), which was higher in lung samples from smokers ( n=10, 0.18±0.17 ng/g d.w, mean ±S.D.) compared to non-smokers ( n=15, 0.046±0.025 ng/g d.w) ( P<0.05), whereas ex-smokers ( n=5), had intermediate levels (0.07±0.03 ng/g d.w). The average level of total BPDE-DNA adducts was 4.46±5.76 per 10 8 bases in smokers, 4.04±2.37 per 10 8 in ex-smokers and 1.76±1.69 per 10 8 in non-smokers. The levels of non-smokers were significantly different ( P<0.05) from the levels of the smokers and ex-smokers combined. Total BPDE-DNA adducts were correlated with BaP levels in the lung samples in which both determinations were obtained ( r=0.63). Our results demonstrate that the biological load of PAHs due to environmental pollution is similar in individuals who smoke and those who do not, but BPDE-DNA adducts are higher in smokers and ex-smokers compared to non-smokers. This study further confirms the usefulness of BPDE-DNA adduct levels determination in the lungs from autopsy samples for monitoring long-term human exposure to BaP, a representative PAH.