Vlasta Svecova

Seasonal variability of oxidative stress markers in city bus drivers: Part I. Oxidative damage to DNA

We investigated the seasonal variability of 8-oxodeoxyguanosine (8-oxodG), a marker of oxidative damage to DNA, in urine of 50 bus drivers and 50 controls in Prague, Czech Republic, in three seasons with different levels of air pollution: winter 2005, summer 2006 and winter 2006. The exposure to environmental pollutants (carcinogenic polycyclic aromatic hydrocarbons, c-PAHs, particulate matter (PM), and volatile organic compounds (VOC)) was monitored by personal and/or stationary monitors. For the analysis of 8-oxodG levels, the ELISA technique was used. Bus drivers were exposed to significantly higher levels of c-PAHs in winter 2006, while in the other two seasons the exposure of controls was unexpectedly higher than that of bus drivers. We did not see any difference in VOC exposure between both groups in summer 2006 and in winter 2006; VOC were not monitored in winter 2005. 8-OxodG levels were higher in bus drivers than in controls in all seasons. The median levels of 8-oxodG (nmol/mmol creatinine) in bus drivers vs. controls were as follows: winter 2005: 7.79 vs. 6.12 (p=0.01); summer 2006: 6.91 vs. 5.11 (p<0.01); winter 2006: 5.73 vs. 3.94 (p<0.001). Multivariate logistic regression analysis identified PM2.5 and PM10 levels, measured by stationary monitors during a 3-day period before urine collection, as the only factors significantly affecting 8-oxodG levels, while the levels of c-PAHs had no significant influence.

Urinary 8-oxodeoxyguanosine levels in children exposed to air pollutants

Oxidative stress is believed to be one of the mechanisms of effects of air pollution to human health. We investigated levels of 8-oxodeoxyguanosine (8-oxodG), a marker of oxidative damage to DNA, in urine samples of 894 children from two districts in the Czech Republic: Teplice and Prachatice. We assessed the association between 8-oxodG levels and exposure to particulate matter of different size: <or=10 microm (PM10), <or=2.5 microm (PM2.5) and carcinogenic polycyclic aromatic hydrocarbons (c-PAHs); as well as between 8-oxodG levels and individual lifestyle, health and pregnancy outcomes. An ELISA technique was used for analysis of 8-oxodG levels. Median levels (range) of 8-oxodG in children from Teplice vs. Prachatice were as follows: 14.6 (3.1-326.5) nmol/mmol vs. 15.2 (3.0-180.8) nmol/mmol creatinine (p=0.34). Levels of 8-oxodG were elevated in children exposed to environmental tobacco smoke (ETS) (p<0.05) and among the Gypsy population (p<0.01). Levels of 8-oxodG decreased with the childs age (p<0.001) and increasing level of the mothers education (p<0.01). Multivariate statistical analyses confirmed the effect of the childs age and ETS exposure on 8-oxodG levels. The exposure to PM10 and PM2.5 measured by stationary monitors during a 7-day period before urine collection, as well as the exposure to c-PAHs measured during 3-day periods 1-3 and 7-9 days before urine collection were identified as factors affecting 8-oxodG levels in multivariate models. The obtained results indicate that 8-oxodG is a sensitive biomarker for measuring the exposure of children to air pollution.

Seasonal variability of oxidative stress markers in city bus drivers. Part II. Oxidative damage to lipids and proteins.

The aim of the present study was to investigate the seasonal variability of markers of oxidative damage to lipids (15-F2t-isoprostane, 15-F2t-IsoP) and proteins (protein carbonyl levels) in 50 bus drivers and 50 controls from Prague, Czech Republic, and to identify factors affecting oxidative stress markers. The samples were collected in three seasons with different levels of air pollution. The exposure to environmental pollutants (carcinogenic polycyclic aromatic hydrocarbons, c-PAHs, particulate matter, PM2.5 and PM10, and volatile organic compounds, VOC) was monitored by personal and/or stationary monitors. For the analysis of both markers, ELISA techniques were used. The median levels of individual markers in bus drivers versus controls were as follows: 15-F2t-IsoP (nmol/mmol creatinine): winter 2005, 0.81 versus 0.68 (p<0.01); summer 2006, 0.62 versus 0.60 (p=0.90); winter 2006, 0.76 versus 0.51 (p<0.001); carbonyl levels (nmol/ml plasma): winter 2005, 14.1 versus 12.9 (p=0.001); summer 2006, 17.5 versus 16.6 (p=0.26); winter 2006, 13.5 versus 11.7 (p<0.001). Multivariate logistic regression identified PM levels measured by stationary monitors over a period 25-27 days before urine collection as a factor positively associated with lipid peroxidation, while protein oxidation levels correlated negatively with both c-PAHs and PM levels. In conclusion, markers of oxidative damage to lipids and proteins were increased in bus drivers in winter seasons, but not in summer. Lipid peroxidation was positively correlated with c-PAHs and PM exposure; protein oxidation correlated negatively and was highest in summer suggesting another factor(s) affecting protein carbonyl levels.

Health impact of air pollution to children.

Health impact of air pollution to children was studied over the last twenty years in heavily polluted parts of the Czech Republic during. The research program (Teplice Program) analyzed these effects in the polluted district Teplice (North Bohemia) and control district Prachatice (Southern Bohemia). Study of pregnancy outcomes for newborns delivered between 1994 and 1998 demonstrated that increase in intrauterine growth retardation (IUGR) was associated with PM10 and c-PAHs exposure (carcinogenic polycyclic aromatic hydrocarbons) in the first month of gestation. Morbidity was followed in the cohort of newborns (N=1492) up to the age of 10years. Coal combustion in homes was associated with increased incidence of lower respiratory track illness and impaired early childhood skeletal growth up to the age of 3years. In preschool children, we observed the effect of increased concentrations of PM2.5 and PAHs on development of bronchitis. The Northern Moravia Region (Silesia) is characterized by high concentrations of c-PAHs due to industrial air pollution. Exposure to B[a]P (benzo[a]pyrene) in Ostrava-Radvanice is the highest in the EU. Children from this part of the city of Ostrava suffered higher incidence of acute respiratory diseases in the first year of life. Gene expression profiles in leukocytes of asthmatic children compared to children without asthma were evaluated in groups from Ostrava-Radvanice and Prachatice. The results suggest the distinct molecular phenotype of asthma bronchiale in children living in polluted Ostrava region compared to children living in Prachatice. The effect of exposure to air pollution to biomarkers in newborns was analyzed in Prague vs. Ceske Budejovice, two locations with different levels of pollution in winter season. B[a]P concentrations were higher in Ceske Budejovice. DNA adducts and micronuclei were also elevated in cord blood in Ceske Budejovice in comparison to Prague. Study of gene expression profiles in the cord blood showed differential expression of 104 genes. Specifically, biological processes related to immune and defense response were down-regulated in Ceske Budejovice. Our studies demonstrate that air pollution significantly affect child health. Especially noticeable is the increase of respiratory morbidity. With the development of molecular epidemiology, we can further evaluate the health risk of air pollution using biomarkers.

Analysis of biomarkers in a Czech population exposed to heavy air pollution. Part I: bulky DNA adducts

The health of human populations living in industrial regions is negatively affected by exposure to environmental air pollutants. In this study, we investigated the impact of air pollution on a cohort of subjects living in Ostrava, a heavily polluted industrial region and compared it with a cohort of individuals from the relatively clean capital city of Prague. This study consisted of three sampling periods differing in the concentrations of major air pollutants (winter 2009, summer 2009 and winter 2010). During all sampling periods, the study subjects from Ostrava region were exposed to significantly higher concentrations of benzo[a]pyrene (B[a]P) and benzene than the subjects in Prague as measured by personal monitors. Pollution by B[a]P, particulate matter of aerodynamic diameter <2.5 µm (PM2.5) and benzene in the Ostrava region measured by stationary monitors was also higher than in Prague, with the exception of PM2.5 in summer 2009 when concentration of the pollutant was significantly elevated in Prague. To evaluate DNA damage in subjects from both locations we determined the levels of bulky DNA adducts in peripheral blood lymphocytes using the (32)P-postlabeling method. Despite higher B[a]P air pollution in the Ostrava region during all sampling periods, the levels of B[a]P-like DNA adducts per 10(8) nucleotides were significantly higher in the Ostrava subjects only in winter 2009 (mean ± SD: 0.21 ± 0.06 versus 0.28 ± 0.08 adducts/10(8) nucleotides, P < 0.001 for Prague and Ostrava subjects, respectively; P < 0.001). During the other two sampling periods, the levels of B[a]P-like DNA adducts were significantly higher in the Prague subjects (P < 0.001). Multivariate analyses conducted among subjects from Ostrava and Prague separately during all sampling periods revealed that exposure to B[a]P and PM2.5 significantly increased levels of B[a]P-like DNA adducts in the Ostrava subjects, but not in subjects from Prague.

The European Hot Spot of B[a]P and PM2.5 Exposure—The Ostrava Region, Czech Republic: Health Research Results

The Ostrava Region in the Czech Republic is a heavily polluted industrial area. Concentrations of PM10, PM2.5, and benzo[a]pyrene (B[a]P) significantly exceed limit values. To investigate the impact of these levels on human health, epidemiological, molecular epidemiology, and in vitro studies were done in 2008–2011. Morbidity of children was followed in 10 pediatric districts. In the most polluted district, children suffered higher incidence of acute respiratory diseases in the first year of life, and higher prevalence of asthma bronchiale. Gene expression was studied in children from Ostrava and from a control rural area. Genes specific to asthma bronchiale differed, suggesting a different molecular phenotype in children in the polluted region compared to children in the control area. A molecular epidemiology study showed adverse effect of the Ostrava exposures, but also an increased expression of XRCC5, which probably protects these exposed subjects against the degree of genetic damage that would otherwise be expected. In vitro studies clearly related concentration of B[a]P from PM2.5 extracts to induced PAH-DNA adducts. These studies clearly demonstrate that under the present local environmental conditions, the health of the population is severely impaired and will likely remain so for a significant period of time.

Personal exposure to carcinogenic polycyclic aromatic hydrocarbons in the Czech Republic

Personal exposures to carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) bound to airborne particulate matter ⩽2.5 μm (PM2.5) were measured in the context of a large-scale molecular epidemiological study in order to identify the impacts of air pollution on human health. Sampling was carried out in three industrial cities in the Czech Republic: Ostrava, Karvina and Havirov. The city of Prague, exhibiting much lower industrial air pollution but a high level of traffic, served as a control. The first monitoring campaigns were held in winter and were repeated in the summer of 2009. The active personal monitors PV 1.7 for PM2.5-bound c-PAHs were used. Non-smoking city policemen from Prague, Karvina and Havirov, and office workers from Ostrava, participated in the study. All participants completed a personal questionnaire and a time-location-activity diary. The average personal winter exposure to c-PAHs (sum of the eight PAHs—benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[g,h,i]perylene, benzo[k]fluoranthene, chrysene, dibenz[a,h]anthracene and indeno[1,2,3-c,d]pyrene) was highest in Karvina, 39.1, followed by Ostrava at 15.1 and Prague at 4.3 ng/m3. The winter levels were significantly higher than the summer values (P<0.001): 4.3 in Karvina, 3.0 in Ostrava, 1.6 in Havirov and 1.0 ng/m3 in Prague. The average personal benzo[a]pyrene winter/summer exposures were: 6.9/0.6 in Karvina, 2.5/0.4 in Ostrava, 0.8/0.1 in Prague and 0.2 ng/m3 in summer in Havirov. In this study, we examined personal exposure to c-PAHs and tested it for associations with potential predictor variables collected from questionnaires, addressing life style factors and day-to-day activities. We found outdoor concentration, environmental tobacco smoke exposure, home heating fuel of coal, wood or gas, frequency of exhaust fan use, cooking and commuting by a car to be the main determinants of personal exposure.

Reduced gene expression levels after chronic exposure to high concentrations of air pollutants.

We analyzed the ability of particulate matter (PM) and chemicals adsorbed onto it to induce diverse gene expression profiles in subjects living in two regions of the Czech Republic differing in levels and sources of the air pollution. A total of 312 samples from polluted Ostrava region and 154 control samples from Prague were collected in winter 2009, summer 2009 and winter 2010. The highest concentrations of air pollutants were detected in winter 2010 when the subjects were exposed to: PM of aerodynamic diameter <2.5μm (PM2.5) (70 vs. 44.9μg/m(3)); benzo[a]pyrene (9.02 vs. 2.56ng/m(3)) and benzene (10.2 vs. 5.5μg/m(3)) in Ostrava and Prague, respectively. Global gene expression analysis of total RNA extracted from leukocytes was performed using Illumina Expression BeadChips microarrays. The expression of selected genes was verified by quantitative real-time PCR (qRT-PCR). Gene expression profiles differed by locations and seasons. Despite lower concentrations of air pollutants a higher number of differentially expressed genes and affected KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways was found in subjects from Prague. In both locations immune response pathways were affected, in Prague also neurodegenerative diseases-related pathways. Over-representation of the latter pathways was associated with the exposure to PM2.5. The qRT-PCR analysis showed a significant decrease in expression of APEX, ATM, FAS, GSTM1, IL1B and RAD21 in subjects from Ostrava, in a comparison of winter 2010 and summer 2009. In Prague, an increase in gene expression was observed for GADD45A and PTGS2. In conclusion, high concentrations of pollutants in Ostrava were not associated with higher number of differentially expressed genes, affected KEGG pathways and expression levels of selected genes. This observation suggests that chronic exposure to air pollution may result in reduced gene expression response with possible negative health consequences.

Personal exposure to volatile organic compounds in the Czech Republic

Personal exposures to volatile organic compounds (VOCs) were measured in the three industrial cities in the Czech Republic, Ostrava, Karvina and Havirov, while the city of Prague served as a control in a large-scale molecular epidemiological study identifying the impacts of air pollution on human health. Office workers from Ostrava and city policemen from Karvina, Havirov and Prague were monitored in the winter and summer of 2009. Only adult non-smokers participated in the study (N=160). Radiello-diffusive passive samplers were used to measure the exposure to benzene, toluene, ethylbenzene, meta- plus para-xylene and ortho-xylene (BTEX). All participants completed a personal questionnaire and a time–location–activity diary (TLAD). The average personal BTEX exposure levels in both seasons were 7.2/34.3/4.4/16.1 μg/m3, respectively. The benzene levels were highest in winter in Karvina, Ostrava and Prague: 8.5, 7.2 and 5.3 μg/m3, respectively. The personal exposures to BTEX were higher than the corresponding stationary monitoring levels detected in the individual localities (P<0.001; except m,p-xylene in summer). The indoor environment, ETS (environmental tobacco smoke), cooking, a home-heating fireplace or gas stove, automobile use and being in a restaurant were important predictors for benzene personal exposure. Ostravas outdoor benzene pollution was a significant factor increasing the exposure of the Ostrava study participants in winter (P<0.05).

Systematic review of the use of the lymphocyte cytokinesis-block micronucleus assay to measure DNA damage induced by exposure to polycyclic aromatic hydrocarbons

The effect of exposure to polycyclic aromatic hydrocarbons (PAHs) to induce micronuclei (MN) measured using the lymphocytes cytokinesis-block micronucleus (CBMN) assay were evaluated in 34 studies according to the exposure: 20 studies in coke oven workers, 7 studies in different occupational exposures as alluminium industry workers, rubber factory workers, road construction workers, airport workers and diesel exposed workers, 6 studies on environmentaly exposed groups as police, volunteers and children. Reviewed papers indicate that the CBMN assay is a sensitive biomarker of PAHs exposure in polluted air. Reviewed studies confirmed previous conclusions, that the frequency of MN measured using the lymphocyte CBMN is not significantly affected by smoking, females are more sensitive to PAHs than males, the frequency of MN is increased with age.