DNA adducts in human placenta as biomarkers for environmental pollution, analysed by the 32P-HPLC method

During pregnancy, mothers are exposed to complex chemical mixtures, such as air pollution and smoke from incomplete combustion. In this study DNA adducts were measured in human placentas from 29 mothers. Environmental exposure and several possible biomarkers in relation to levels of DNA adducts were measured. Placental aromatic and bulky DNA adducts were measured with the 32 P-HPLC method. Mothers living in an urban area in Estonia had significantly higher levels of DNA adducts compared with mothers living in a rural area of Estonia and in Switzerland (19.38±6.91 per 10 8 normal nucleotides [NN] vs 10.35±6.87 10 8 NN and 8.09±6.59 10 8 NN, respectively; P<0.01). No significant correlation was found between smoking and DNA adduct levels for any of the subjects. Among the potential biomarkers tested, a possible correlation was found between DNA adducts and placental copper in the environmentally polluted area, and a correlation was found between DNA adducts and glutathione S-transferase (GST) activity for Swiss mothers abusing drugs. The levels of DNA adducts in the drug abusers were not higher than those of the controls; in fact they were lower. These data suggest that the presence of DNA adducts in human placenta is an environmental biomarker for polluted areas. A further conclusion is that air pollutants to which pregnant women are exposed can induce DNA damage in the placenta and consequently risk exposing the foetus to genotoxins.