[Show abstract][Hide abstract]ABSTRACT: Bulky DNA adducts reflect genotoxic exposures, have been associated with lower birthweight and may predict cancer risk.
We selected factors known or hypothesized to affect in utero adduct formation and repair and examined their associations with adduct levels in neonates.
Pregnant women from Greece, Spain, England, Denmark and Norway were recruited in 2006-2010. Cord blood bulky DNA adduct levels were measured by the (32)P-postlabelling technique (n=511). Diet and maternal characteristics were assessed via questionnaires. Modeled exposures to air pollutants and drinking-water disinfection by-products, mainly trihalomethanes (THMs) were available for a large proportion of the study population.
Greek and Spanish neonates had higher adduct levels than the Northern European neonates (median: 12.1 (n=179) vs. 6.8 (n=332) adducts per 10(8) nucleotides, p<0.001). Being from the Southern European countries, higher maternal body mass-index, delivery by Caesarean section, being boy, low maternal intake of fruits rich in vitamin C, high intake of dairy products and low adherence to healthy diet score were statistically significantly associated with higher adduct levels in adjusted models. Air pollution exposure to PM2.5 and NO2 was associated with significantly higher adducts in the Danish subsample only. Overall, the pooled results for THMs in water show no evidence of association with adduct levels; however, there are country-specific differences in results with a suggestion of an association in England.
These findings suggest that a combination of factors, including unknown country-specific factors, influence the bulky DNA adduct levels in neonates.
Full-text available · Article · Jan 2015 · Environmental Health Perspectives
[Show abstract][Hide abstract]ABSTRACT: Purpose
Nutrients and food constituents can prevent or contribute to genotoxicity. In this study, the possible influence of a vegetarian/non-vegetarian diet on genotoxic effects was investigated in 58 non-smoking healthy vegetarians (V) and non-vegetarians (NV), age 21–37 years from the Stockholm area in Sweden.
Physical activity and dietary habits were similar in both groups, with the exception of the intake of meat and fish. Using flow cytometry, we determined the formation of micronuclei (MN) in transferrin-positive immature peripheral blood reticulocytes (Trf-Ret) (Total: n = 53; V: n = 27; NV: n = 26). Dietary exposure to acrylamide was measured through hemoglobin (Hb) adducts in peripheral erythrocytes (Total: n = 53; V: n = 29; NV: n = 24). Hb adducts of both acrylamide and its genotoxic metabolite glycidamide were monitored as a measure of the corresponding in vivo doses.
Our data demonstrated that compared with the non-vegetarians, the vegetarians exhibited lower frequencies of MN (fMN) in the Trf-Ret (p
Article · Nov 2014 · European Journal of Nutrition
[Show abstract][Hide abstract]ABSTRACT: Stable and specific biomacromolecular adducts can be used to measure in vivo doses of reactive compounds. An LC/MS-MS method to measure adducts from the benzo[a]pyrene (BP) metabolite (±)-anti-BP-7,8-diol-9,10-epoxide ((±)-anti-BPDE) to His(146) in serum albumin (SA), earlier evaluated on in vitro alkylated human SA, was tested for its applicability to mouse. It was shown that (+)-anti-BPDE form BPDE-His adducts to mouse SA. The method was applied to samples from BP-exposed mice (100mg/kg of body weight for 1, 3, 7 and 28 days). BPDE-His in SA was close to the limit of quantification and showed the highest level (13fmol/mg) 3 days after exposure. The level was 400 times lower (calculated per g macromolecule) than earlier measured level of BPDE-adduct to deoxyguanosine (dG) in DNA in the livers. The relative rate of formation of adducts from BPDE with His in SA and with dG in DNA was investigated. Quantification by LC/MS-MS of the adducts in human blood alkylated in vitro with (±)-anti-BPDE showed a 1850 times higher level of BPDE-dG compared to BPDE-His. The specific and stable BPDE-adducts to His in SA are potential biomarkers of in vivo dose of BPDE, though this requires a considerable improved analytical sensitivity of the LC/MS-MS method.
[Show abstract][Hide abstract]ABSTRACT: Skin cancer is caused by solar ultraviolet radiation (UVR), which is also essential for vitamin D production. DNA damage (thymine dimers: T-T dimers) and vitamin D (25(OH)D) synthesis are both initiated by solar ultraviolet B radiation (UVB). We aimed to investigate the simultaneous adverse and beneficial effects of solar UVB exposure in holidaymakers. Sun-seekers and skiers (n=71) were observed over 6 days with on-site monitoring, personal diaries, and recording of personal UVB exposure doses with electronic dosimeters. Urine and blood samples were analysed for T-T dimers and 25(OH)D, respectively. The volunteers had a statistically significant increase in vitamin D. There were strong associations between UVB exposure and post-holiday levels of T-T dimers and vitamin D, as well as between post-holiday T-T dimers and vitamin D. We conclude that UVB induced vitamin D synthesis is associated with considerable DNA damage in the skin. These data, on two major health predictors, provide a basis for further field studies that may result in better understanding of the risks and benefits of "real life" solar exposure. However, vitamin D status can be improved more safely through the use of vitamin D dietary supplements.Journal of Investigative Dermatology accepted article preview online, 20 May 2014; doi:10.1038/jid.2014.223.
Full-text available · Article · May 2014 · Journal of Investigative Dermatology
[Show abstract][Hide abstract]ABSTRACT: Maternal exposure to dioxins and dioxin-like compounds may affect fetal growth and development. We evaluated the association between in utero dioxin-like activity and birth outcomes in a prospective European mother-child study.
We measured dioxin-like activity in maternal and cord blood plasma samples collected at delivery using the Dioxin-Responsive Chemically Activated LUciferase eXpression (DR CALUX) bioassay in 967 mother-child pairs, in Denmark, Greece, Norway, Spain, and England. Multiple linear regression models were used to investigate the associations with birth weight, gestational age, and head circumference.
Plasma dioxin-like activity was higher in maternal sample than in cord samples. Birth weight was lower with medium (-58 g [95% confidence interval (CI) = -176 to 62]) and high (-82 g [-216 to 53]) tertiles of exposure (cord blood) compared with the lowest tertile. Gestational age was shorter by approximately half a week in the highest compared with the lowest (-0.4 weeks [95% CI = -0.8 to -0.1]). This association was stronger in boys than in girls, although the statistical evidence for interaction was weak (P = 0.22). Analysis based on CALUX-toxic equivalents expressed per milliliter of plasma showed similar trends. We found no association between dioxin-like activity in maternal plasma and birth outcomes.
Results from this international general population study suggest an association between low-level prenatal dioxin-like activity and shorter gestational age, particularly in boys, with weaker associations for birth weight.
Article · Mar 2014 · Epidemiology (Cambridge, Mass.)
[Show abstract][Hide abstract]ABSTRACT: Leukemia incidence has increased in recent decades among European children, suggesting that early-life environmental exposures play an important role in disease development. Objectives: We investigated the hypothesis that childhood susceptibility may increase as a result of in utero exposure to carcinogens and hormonally acting factors. Using cord blood samples from the NewGeneris cohort, we examined associations between a range of biomarkers of carcinogen exposure and hormonally acting factors with micronuclei (MN) frequency as a proxy measure of cancer risk. Associations with gene expression and genotype were also explored. Methods: DNA and protein adducts, gene expression profiles, circulating hormonally acting factors, and GWAS (genome-wide association study) data were investigated in relation to genomic damage measured by MN frequency in lymphocytes from 623 newborns enrolled between 2006 and 2010 across Europe. Results: Malondialdehyde DNA adducts (M1dG) were associated with increased MN frequency in binucleated lymphocytes (MNBN), and exposure to androgenic, estrogenic, and dioxin-like compounds was associated with MN frequency in mononucleated lymphocytes (MNMONO), although no monotonic exposure-outcome relationship was observed. Lower frequencies of MNBN were associated with a 1-unit increase expression of PDCD11, LATS2, TRIM13, CD28, SMC1A, IL7R, and NIPBL genes. Gene expression was significantly higher in association with the highest versus lowest category of bulky and M1dG-DNA adducts for five and six genes, respectively. Gene expression levels were significantly lower for 11 genes in association with the highest versus lowest category of plasma AR CALUX® (chemically activated luciferase expression for androgens) (8 genes), ERα CALUX® (for estrogens) (2 genes), and DR CALUX® (for dioxins). Several SNPs (single-nucleotide polymorphisms) on chromosome 11 near FOLH1 significantly modified associations between androgen activity and MNBN frequency. Polymorphisms in EPHX1/2 and CYP2E1 were associated with MNBN. Conclusion: We measured in utero exposure to selected environmental carcinogens and circulating hormonally acting factors and detected associations with MN frequency in newborns circulating T lymphocytes. The results highlight mechanisms that may contribute to carcinogen-induced leukemia and require further research.
Article · Feb 2014 · Environmental Health Perspectives
[Show abstract][Hide abstract]ABSTRACT: Leukemia incidence has increased in recent decades amongst European children suggesting early-life environmental exposures play an important role in disease development.
We investigated the hypothesis that childhood susceptibility may increase as a result of in utero exposure to carcinogens and hormonally acting factors. Utilizing cord blood samples from the NewGeneris cohort, we examined associations between a range of biomarkers of carcinogen exposure and hormonally acting factors with micronuclei (MN) frequency as a proxy measure of cancer risk. Associations with gene expression and genotype were also explored.
DNA and protein adducts, gene expression profiles, circulating hormonally acting factors, and GWAS data were investigated in relation to genomic damage measured by MN frequency in lymphocytes from 623 newborns enrolled between 2006-2010 across Europe.
Malondialdehyde DNA-adducts (M1dG) were associated with increased MN frequency in binucleated lymphocytes (MNBN) and exposure to androgenic, estrogenic, and dioxin-like compounds was associated with MN frequency in mononucleated lymphocytes (MNMONO), although no monotonic exposure-outcome relationship was observed. Lower frequencies of MNBN were associated with a 1-unit increase expression of PDCD11, LATS2, TRIM13, CD28, SMC1A, IL7R, and NIPBL genes. Gene expression was significantly higher in association with the highest versus lowest category of bulky- and M1dG-DNA adducts for five and six genes, respectively. Gene expression levels were significantly lower for 11 genes in association with the highest versus lowest category of plasma AR-CALUX® (8 genes), ERα-CALUX® (2 genes), and DR-CALUX®. Several SNPs on chromosome 11 near FOLH1 significantly modified associations between androgen activity and MNBN frequency. Polymorphisms in EPHX1/2 and CYP2E1 were associated with MNBN.
We measured in utero exposure to selected environmental carcinogens and circulating hormonally acting factors and detected associations with MN frequency in newborns circulating T-lymphocytes. The results highlight mechanisms that may contribute to carcinogen-induced leukemia and require further research.
Full-text available · Article · Nov 2013 · Environmental Health Perspectives
[Show abstract][Hide abstract]ABSTRACT: Tobacco-smoke, airborne, and dietary exposures to polycyclic aromatic hydrocarbons (PAHs) have been associated with reduced prenatal growth. Evidence from biomarker-based studies of low-exposed populations is limited. Bulky DNA adducts in cord blood reflect the prenatal effective dose to several genotoxic agents including PAHs.
We estimated the association between bulky DNA adduct levels and birth weight in a multicenter study and examined modification of this association by maternal fruit and vegetable intake during pregnancy.
Pregnant women from Denmark, England, Greece, Norway, and Spain were recruited in 2006-2010. Adduct levels were measured by the (32)P-postlabelling technique in white blood cells from 229 mothers and 612 newborns. Maternal diet was examined through questionnaires.
Adduct levels in maternal and cord blood samples were similar and positively correlated (median, 12.1 vs. 11.4 adducts in 10(8) nucleotides; Spearman rank correlation coefficient=0.66, p<0.001). Cord blood adduct levels were negatively associated with birth weight, with an estimated difference in mean birth weight of -129 g (95% CI: -233, -25) for infants in the highest versus lowest tertile of adducts. The negative association with birth weight was limited to births in Norway, Denmark, and England, the countries with the lowest adduct levels, and was more pronounced in births to mothers with low intake of fruit and vegetables (-248 g; 95% CI: -405, -92) compared to those with high intake (-58 g; 95% CI: -206, 90) CONCLUSIONS: Maternal exposure to genotoxic agents that induce the formation of bulky DNA adducts may affect intrauterine growth. Maternal fruit and vegetable consumption may be protective.
Full-text available · Article · Jul 2013 · Environmental Health Perspectives
[Show abstract][Hide abstract]ABSTRACT: To gain a deeper insight into the potential interactions between individual aromatic hydrocarbons in a mixture, several benzo[a]pyrene (B[a]P) and 7H-dibenzo[c,g]carbazole (DBC) binary mixtures were studied. The biological activity of the binary mixtures was investigated in the HepG2 and WB-F344 liver cell lines and the Chinese hamster V79 cell line that stably expresses the human cytochrome P450 1A1 (hCYP1A1). In the V79 cells, binary mixtures, in contrast to individual carcinogens, caused a significant decrease in the levels of micronuclei, DNA adducts and gene mutations, but not in cell survival. Similarly, a lower frequency of micronuclei and levels of DNA adducts was found in rat liver WB-F344 cells treated with a binary mixture, regardless of the exposure time. The observed antagonism between B[a]P and DBC may be due to an inhibition of Cyp1a1 expression because cells exposed to B[a]P:DBC showed a decrease in Cyp1a1 mRNA levels. In human liver HepG2 cells exposed to binary mixtures for 2 h, a reduction in micronuclei frequency was also found. However, after a 24 h treatment, synergism between B[a]P and DBC was determined based on DNA -adduct formation. Accordingly, the up-regulation of CYP1A1 expression was detected in HepG2 cells exposed to B[a]P:DBC. Our results show significant differences in the response of human and rat cells to B[a]P:DBC mixtures and stress the need to use multiple experimental systems when evaluating the potential risk of environmental pollutants. Our data also indicate that an increased expression of CYP1A1 results in a synergistic effect of B[a]P and DBC in human cells. As humans are exposed to a plethora of noxious chemicals, our results have important implications for human carcinogenesis.
Full-text available · Article · Apr 2013 · Toxicology and Applied Pharmacology
[Show abstract][Hide abstract]ABSTRACT: Abstract Exposure of the general population to polycyclic aromatic hydrocarbons (PAH) is ubiquitous. The aim of this study was to analyze biomarkers associated with the uptake of PAH in 428 non-smoking women from Łodz (Poland), Viterbo (Italy), Belgrade (Serbia) and from the Pančevo area, where the petrochemical complex was destroyed by the air raids in 1999. Urinary excretion of PAH metabolites was lowest in Italian women, intermediary for Serbian and highest in Polish women, who predominantly excreted hydroxy phenanthrenes as metabolites of phenanthrene. Bulky DNA adduct levels were highest in Italian and Polish women. Genotype or PAH ambient air levels could not explain the dissimilarities between the study groups with respect to biomarker patterns, which probably reflected differences in life style-associated factors.
[Show abstract][Hide abstract]ABSTRACT: The incidence of skin cancer is rising rapidly in many countries, presumably due to increased leisure time exposure to solar
ultraviolet radiation (UVR). UVR causes DNA lesions, such as the thymine dimer (T=T), which have been causatively linked to
the development of skin cancer. T=T is clearly detectable in urine and may, thereby, be a potentially valuable biomarker of
UVR exposure. The objective of this study was to evaluate the relationship between UVR exposure and urinary levels of T=T
in a field study involving outdoor workers. Daily ambient and personal exposure of 52 beach lifeguards and agricultural workers
to UVR were determined (employing 656 personal polysulphone dosimeters). In 22 of these subjects, daily urinary T=T levels
(120 samples) were measured, the area of skin exposed calculated and associations assessed utilizing mixed statistical models.
The average daily UVR dose was approximately 600 J/m2 (7.7 standard erythemal doses), i.e. about 20% of ambient UVR. T=T levels were correlated to UVR dose, increasing by about
6fmol/µmol creatinine for each 100 J/m2 increase in dose (average of the three preceding days). This is the first demonstration of a relationship between occupational
UVR exposure and urinary levels of a biomarker of DNA damage. On a population level, urinary levels of T=T can be used as
a biomarker for UVR exposure in the field.
Full-text available · Article · Jan 2013 · Mutagenesis
[Show abstract][Hide abstract]ABSTRACT: Background: Acrylamide is a common dietary exposure that crosses the human placenta. It is classified as a probable human carcinogen, and developmental toxicity has been observed in rodents.
Objectives: We examined the associations between prenatal exposure to acrylamide and birth outcomes in a prospective European mother–child study.
Methods: Hemoglobin (Hb) adducts of acrylamide and its metabolite glycidamide were measured in cord blood (reflecting cumulated exposure in the last months of pregnancy) from 1,101 singleton pregnant women recruited in Denmark, England, Greece, Norway, and Spain during 2006–2010. Maternal diet was estimated through food-frequency questionnaires.
Results: Both acrylamide and glycidamide Hb adducts were associated with a statistically significant reduction in birth weight and head circumference. The estimated difference in birth weight for infants in the highest versus lowest quartile of acrylamide Hb adduct levels after adjusting for gestational age and country was –132 g (95% CI: –207, –56); the corresponding difference for head circumference was –0.33 cm (95% CI: –0.61, –0.06). Findings were similar in infants of nonsmokers, were consistent across countries, and remained after adjustment for factors associated with reduced birth weight. Maternal consumption of foods rich in acrylamide, such as fried potatoes, was associated with cord blood acrylamide adduct levels and with reduced birth weight.
Conclusions: Dietary exposure to acrylamide was associated with reduced birth weight and head circumference. Consumption of specific foods during pregnancy was associated with higher acrylamide exposure in utero. If confirmed, these findings suggest that dietary intake of acrylamide should be reduced among pregnant women.
Full-text available · Article · Oct 2012 · Environmental Health Perspectives
[Show abstract][Hide abstract]ABSTRACT: Context: DNA damage following exposure to ultraviolet radiation (UVR) is important in skin cancer development. The predominant photoproduct, cyclobutane thymine dimer (T=T), is repaired and excreted in the urine, where it provides a biomarker of exposure. Objective: To quantify urinary T=T levels after recreational sunlight exposure in adults and children. Methods: Average UVR doses were measured with personal dosimeters. Urinary T=T was analysed with (32)P-postlabelling. Results: Background levels of T=T increased significantly following exposure to sunlight. Amounts of T=T in urine of children and adults were not significantly different after adjusting for area of skin exposed and physiological differences. UVR dose and amounts of T=T correlated for both adults and children. Conclusion: Recreational exposure to sunlight in Sweden induces levels of DNA damage, clearly detectable in urine.
[Show abstract][Hide abstract]ABSTRACT: Epidemiological studies have shown an association between alcohol (ethanol) consumption and increased cancer risk. The effect of alcohol consumption on the levels and persistence of N(2)-ethylidene-2'-deoxyguanosine (N(2)-ethylidene-dG) formed by acetaldehyde, the oxidative metabolite of ethanol, in human leukocyte DNA was investigated. DNA was isolated from venous blood samples obtained from 30 male non-smoking individuals before consumption of alcohol (0h) and subsequently at 3-5h following the consumption of 150mL of vodka (containing 42% pure ethanol). Additional samples were collected 24h and 48h post-alcohol consumption. The levels of N(2)-ethyl-2'-deoxyguanosine (N(2)-ethyl-dG) in the DNA were determined following reduction of N(2)-ethylidene-dG with sodium cyanoborohydride using a liquid chromatography-tandem mass spectrometry selected reaction monitoring method. A slight time-dependent trend showing an increase and decrease in the levels of N(2)-ethyl-dG was observed following consumption of alcohol compared to time 0h, however, the differences were not statistically significant. The average levels of N(2)-ethyl-dG observed at 0h, 3-5h, 24h and 48h time points following ingestion of alcohol were 34.6±21.9, 35.1±21.0, 36.8±20.7 and 35.6±21.1 per 10(8) 2'-deoxynucleosides, respectively. In conclusion, alcohol consumption that could be encountered under social drinking conditions, does not significantly alter the levels of the acetaldehyde derived DNA adduct, N(2)-ethyl-dG in human leukocyte DNA from healthy individuals.
Article · Jul 2012 · Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
[Show abstract][Hide abstract]ABSTRACT: The knowledge about fetal exposure to acrylamide/glycidamide from the maternal exposure through food is limited. Acrylamide, glycidamide, and ethylene oxide are electrophiles and form adducts with hemoglobin (Hb), which could be used for in vivo dose measurement. In this study, a method for analysis of Hb adducts by liquid chromatography-mass spectrometry, the adduct FIRE procedure, was applied to measurements of adducts from these compounds in maternal blood samples (n = 87) and umbilical cord blood samples (n = 219). The adduct levels from the three compounds, acrylamide, glycidamide, and ethylene oxide, were increased in tobacco smokers. Highly significant correlations were found between cord and maternal blood with regard to measured adduct levels of the three compounds. The mean cord/maternal hemoglobin adduct level ratios were 0.48 (range 0.27-0.86) for acrylamide, 0.38 (range 0.20-0.73) for glycidamide, and 0.43 (range 0.17-1.34) for ethylene oxide. In vitro studies with acrylamide and glycidamide showed a lower (0.38-0.48) rate of adduct formation with Hb in cord blood than with Hb in maternal blood, which is compatible with the structural differences in fetal and adult Hb. Together, these results indicate a similar life span of fetal and maternal erythrocytes. The results showed that the in vivo dose in fetal and maternal blood is about the same and that the placenta gives negligible protection of the fetus to exposure from the investigated compounds. A trend of higher levels of the measured adducts in cord blood with gestational age was observed, which may reflect the gestational age-related change of the cord blood Hb composition toward a higher content of adult Hb. The results suggest that the Hb adduct levels measured in cord blood reflect the exposure to the fetus during the third trimester. The evaluation of the new analytical method showed that it is suitable for monitoring of background exposures of the investigated electrophilic compounds in large population studies.
Article · Sep 2011 · Chemical Research in Toxicology
[Show abstract][Hide abstract]ABSTRACT: Acrylamide (AA) is produced in many types of food products cooked or processed at high temperature. AA is metabolized to the epoxide glycidamide (GA), which can bind to deoxyguanosine and deoxyadenosine in DNA. The GA-derived N7-guanine and N3-adenine adducts are the only products which so far have been analysed in vivo. Because of previous excellent experience from analysis of adducts to N1-adenine, the aim of our study was to investigate if the N1-adenine adduct of GA could be used as a biomarker of AA exposure. A ³²P-postlabelling method was developed and tested (a) on DNA modified in vitro with GA, (b) on cells treated with GA and (c) on liver DNA from mice treated with AA. The N1-adenine adduct of GA (analysed after conversion to N⁶-GA-deoxyadenosine-5'-monophosphate) was easily detected in DNA reacted with GA and in DNA from cells exposed to GA, but not in DNA from mice treated with AA. The reason for this is currently not clearly understood, but some of the possible contributing factors are discussed. The application of the method in other experimental conditions should be further pursued in order to solve this matter.