Comparison between smoking-related DNA adduct analysis in induced sputum and peripheral blood lymphocytes

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Abstract

We investigated the applicability of induced sputum (IS), a non-invasive derivative from the lower respiratory tract, for smoking-related DNA adduct analysis and its comparability with peripheral blood lymphocytes (PBL), Lipophilic DNA adducts were quantified by the P-32-post-labeling assay in IS and PBL of smokers (n = 9) with stable smoking status at three time points tone week intervals) and nonsmokers (n = 9) at one time point. The success rate for sputum induction was 100% at all time points. There was no significant difference in total cell count, cell viability, squamous cell count and DNA yield between smokers and non-smokers. Within the smokers, there was no significant difference in IS cytology at the three time points: overall (mean of three measurements) total cell count, 9.0 +/- 2.4 x 10(6); cell viability, 77 +/- 4%; squamous cell count, 28 +/- 5%; non-squamous cell count, 72 +/- 4% (bronchoalveolar macrophages, 75 +/- 6%; neutrophils, 17 +/- 3%; bronchoepithelial cells, 7 +/- 2%; lymphocytes, 0.7 +/- 0.2%; metachromatic cells, 0.3 +/- 0.2%). IS DNA yield did not differ significantly at the three time points [overall (mean of three extractions) DNA yield, 66 +/- 20 mu g]. A typical smoking-associated diagonal radioactive zone was observed in the adduct maps of IS and PBL of all and five smokers, respectively, and of none of the non-smokers. Lipophilic DNA adduct levels in both IS and PBL of smokers were higher than those of non-smokers (3.7 +/- 0.9 versus 0.7 +/- 0.2/10(8) nt, P = 0.0005, and 2.1 +/- 0.3 versus 0.6 +/- 0.1/10(8) nt, P = 0.0001, respectively). In smokers the level of adducts in IS was non-significantly higher than that in PBL (3.7 +/- 0.9 versus 2.1 +/- 0.3/10(8) nt, P = 0.1), whilst in non-smokers the difference was not appreciable (0.7 +/- 0.2 versus 0.6 +/- 0.1/10(8) nt), Within the smokers there was no significant change in the level of adducts at the three time points either in IS or in PBL (coefficients of variation 34 and 29%, respectively). Adduct levels in IS at each time point were higher than those in PBL, leading to a significantly higher overall (mean of three quantifications) level of adducts in IS than PBL (3.3 +/- 0.2 versus 2.1 +/- 0.1/10s nt, P = 0.02). The overall levels of adducts in both IS and PBL were dose-dependently related to smoking indites. We conclude that IS is a preferable matrix as compared with PBL for molecular dosimetry of (current) exposure to inhalatory carcinogens as its analysis reveals both the existence and the magnitude of exposure more explicitly.
Original languageEnglish
Pages (from-to)1335-1340
Number of pages6
JournalCarcinogenesis
Volume21
DOIs
Publication statusPublished - 1 Jan 2000

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