Environmental exposure to carcinogenic polycyclic aromatic hydrocarbons--the interpretation of cytogenetic analysis by FISH

The capital city of Prague is one of the most polluted localities of the Czech Republic. The effect of exposure to carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) adsorbed onto respirable air particles (<2.5 microm) on chromosomal aberrations was studied in a group of city policemen (street patrol, aged 34+/-8 years) working in the downtown area of Prague and spending daily >8h outdoors (N=61) in months of January and March 2004. Ambient air particles (PM10, PM2.5) and c-PAHs were monitored using Versatile Air Pollution Sampler (VAPS), and personal exposure was evaluated using personal samplers during working shift. Chromosomal aberrations were analyzed by fluorescent in situ hybridization (FISH) and conventional cytogenetic analysis. Urinary cotinine, plasma levels of vitamins A, E and C, folate, total cholesterol, HDL, LDL cholesterols and triglycerides were also analyzed as possible effect modifiers. During the sampling period the particulate air pollution monitored by VAPS was in January versus March as follows: PM10 55.6 microg/m3 versus 36.4 microg/m3, PM2.5 44.4 microg/m3 versus 24.8 microg/m3, c-PAHs 19.7 ng/m3 versus 3.6 ng/m3, and Ba]P 4.3 ng/m3 versus 0.8 ng/m3. Significant differences were observed for all FISH endpoints studied for the sampling in January and March (%AB.C.=0.27+/-0.18 versus 0.16+/-0.17, p<0.001, F(G)/100=1.32+/-1.07 versus 0.85+/-0.95, p<0.01, AB/1000 (aberrations/1000 cells)=4.27+/-3.09 versus 2.59+/-2.79, p<0.001) while conventional cytogenetic analysis did not reveal any differences in the frequency of chromosomal aberrations. Factors associated with an increased level of translocations by FISH indicated the effect of age, cholesterol, LDL-cholesterol and vitamin C. We may conclude that FISH indicates that the city policemen in Prague represent a group of increased genotoxic risk. This is the first study reporting that translocations induced by c-PAHs in peripheral lymphocytes last only several weeks.