Urinary 8-OHdG Research Articles

Effects of exposure to polycyclic aromatic hydrocarbons and heavy metals on the oxidative stress, inflammation and DNA methylation among traffic conductors

Background: Exposure to traffic-related air pollutants, including polycyclic aromatic hydrocarbons (PAHs) and heavy metals, has been associated with the etiology and prognosis of many diseases including cardiovascular events. However, the specific causal agents and underlying mechanisms for different adverse health effects remain unclear. Objectives: The aims of this study were to examine the relations of exposure to PAHs (1-hydroxypyrene-glucuronide, 1-OHPG) and metals (cadmium, Cd; nickel, Ni; lead, Pb; and copper, Cu) with lipid peroxidation (4-hydroxynonenal, 4-HNE), inflammation (high-sensitive C-creative protein, hs-CRP), endothelial function (vascular cell adhesion molecule-1,VCAM-1; intercellular adhesion molecule-1, ICAM-1), DNA damage (8-hydroxydeoxyguanosine, 8-OHdG) and DNA methylation (long interspersed nuclear element-1, LINE-1). Methods: we recruited 91 traffic conductors and 53 indoor official workers between May 2009 and June 2011 in Taipei, Taiwan. Post-shift blood and urine samples from 2 consecutive days were collected. The urine samples were analyzed for 1-OHPG, Cd, Ni, As, Pb, Cu, and 8-OHdG. The blood samples were measured for HNE, hs-CRP, VCAM-1, ICAM-1, and LINE-1. We constructed a linear mixed model to assess these associations adjusted for covariates. Results: We found that urinary 1-OHPG levels were positively associated with urinary 8-OHdG levels (β=0.09, p=0.026), and urinary 8-OHdG levels were negatively associated with LINE-1 methylation levels (β= -0.85, p=0.021) among traffic conductors. Significant positive relations between urinary As and Pb levels and HNE levels, and between all urinary metals levels and ICAM-1 levels, and between urinary Pb levels and VCAM-1 levels, as well as between urinary Ni levels and hs-CRP levels were observed in traffic conductors. Conclusions: Exposure to PAHs and metals could increase the burden of oxidative stress and inflammation, and oxidative stress could result in global DNA hypomethylation.

Concurrent quantification of multiple biomarkers indicative of oxidative stress status using liquid chromatography-tandem mass spectrometry

8-Hydroxy-2-deoxyguanosine (8-OHdG), 8-nitroguanine (8-NO2Gua), 8-iso-prostaglandin F2α (8-IsoPGF2α), and N-acetyl-S-(tetrahydro-5-hydroxy-2-pentyl-3-furanyl)-L-cysteine (HNE-MA) are well-studied and representative biomarkers for oxidative DNA damage, inflammation, and lipid peroxidation; all of which have been associated with increases in risks of various diseases and cancers. A rapid and highly sensitive isotope-dilution liquid-chromatography tandem mass spectrometry (LC-MS/MS) method was developed to simultaneously quantify the aforementioned biomarkers in urine. Upon validation, this method shows excellent feasibility, sensitivity (0.008–0.03 ng/mL) and satisfactory recoveries (88.7–95.4%); the calibration curves displayed excellent linearity with coefficients of determination (R2) greater than 0.998. Additionally, low variations were observed in the relative standard deviation for intra- and inter-day measurements for the four analytes. The relative matrix effects for all four analytes ranged from 2.04 to 3.27%, which signaled that interferences from endogenous levels of the analytes were deemed statistically insignificant. This study successfully developed an analytical method capable to simultaneously quantify urinary 8-OHdG, 8-NO2Gua, 8-IsoPGF2α, and HNE-MA. This analytical protocol can be applied towards conducting epidemiological studies to reveal the mechanisms related to disease development, and thus evaluate the associated risks of diseases.

Effects of dietary green tea polyphenol supplementation on the health of workers exposed to high-voltage power lines.

Although it has been several decades since the focus on the effect of extremely low frequency electromagnetic fields (ELF-EMF) of high-voltage power lines on human health, no consistent conclusion has been drawn. The present study aimed to investigate the change in oxidative stress after exposure to ELF-EMFs, and potential protective effects of green tea polyphenol supplementation (GTPS) on ELF-EMFs induced oxidative stress. A total of 867 subjects, including workers with or without exposure to ELF-EMFs of 110-420kV power lines, participated and were randomized into GTPS and placebo treatment groups. Oxidative stress and oxidative damage to DNA were assessed by urinary tests of 8-isoprostane and 8-OHdG. Significant increased urinary 8-isoprostane and 8-OHdG were observed in workers with ELF-EMFs exposure, which were diminished after 12 months of GTPS. No protective effects of GTPS on oxidative stress and oxidative damage to DNA were observed after three months of GTPS withdraw. We found a negative impact of high-voltage power lines on the health of workers. Long-term GTPS could be an efficient protection against the health issues induced by high-voltage power lines.

Association of air pollution sources and aldehydes with biomarkers of blood coagulation, pulmonary inflammation, and systemic oxidative stress.

Using data collected before, during, and after the 2008 Summer Olympic Games in Beijing, this study examines associations between biomarkers of blood coagulation (vWF, sCD62P and sCD40L), pulmonary inflammation (EBC pH, EBC nitrite, and eNO), and systemic oxidative stress (urinary 8-OHdG) with sources of air pollution identified utilizing principal component analysis and with concentrations of three aldehydes of health concern. Associations between the biomarkers and the air pollution source types and aldehydes were examined using a linear mixed effects model, regressing through seven lag days and controlling for ambient temperature, relative humidity, gender, and day of week for the biomarker measurements. The biomarkers for pulmonary inflammation, particularly EBC pH and eNO, were most consistently associated with vehicle and industrial combustion, oil combustion, and vegetative burning. The biomarkers for blood coagulation, particularly vWF and sCD62p, were most consistently associated with oil combustion. Systemic oxidative stress biomarker (8-OHdG) was most consistently associated with vehicle and industrial combustion. The associations of the biomarkers were generally not significant or consistent with secondary formation of pollutants and with the aldehydes. The findings support policies to control anthropogenic pollution sources rather than natural soil or road dust from a cardio-respiratory health standpoint.

Cocaine effects on generation of reactive oxygen species and DNA damage: formation of 8-hydroxydeoxyguanosine in active abusers

Cocaine abuse continues to be a major public health problem in the world. An upper numbers of individuals are initiating cocaine use with a stable rate of growth each year with an increasing number of people with cocaine related problems. Following cocaine oxidative pathways a ROS formation are generated. Oxidative stress has been demonstrated to play an important role in cocaine addiction and toxicity due to its oxidized metabolites produced by cytochrome P450 during cocaine biotransformation. The ROS induced genotoxicities include DNA damage, gene mutation, chromosome aberrations and micronuclei formation. 8-Hydroxy-2’-deoxyguanosine (8-OHdG) an oxidative modified DNA product, is the most representative product that may reflect oxidative damage induced by ROS. The present study was designed to investigate whether a systemic cocaine administration and its metabolism increase 8-OHdG production. Our findings clearly showed that cocaine promoted the ROS formation with significant increased of urinary 8-OHdG and MDA with a decreased of total scavenging capacity (TSC).

Simultaneous, rapid, and sensitive quantification of 8-hydroxy-2'-deoxyguanosine and cotinine in human urine by on-line solid-phase extraction LC-MS/MS: correlation with tobacco exposure biomarkers NNAL.

Cigarette smoke can increase oxidative DNA damage. The main component in cigarette smoke is nicotine. Nicotine is metabolized to cotinine, which can be regarded as a biomarker for measuring exposure to tobacco smoke. A sensitive, simple, and robust method based on on-line solid-phase extraction liquid chromatography with tandem mass spectrometry (on-line SPE LC-MS/MS) has been developed and validated for the simultaneous determination of 8-OHdG and cotinine. The matrix effects of 8-OHdG and cotinine were measured at 97.1 and 91.7%, with values for CV at 4.4 and 4.2%, respectively. The limits of detection of 8-OHdG and cotinine were 10.0 and 5.5pgmL(-1), and the limits of quantification were 40.0 and 20.0pgmL(-1), respectively. The total run time was 12min. We quantified 8-OHdG and cotinine in the urine of 80 male subjects. The results showed the levels of 8-OHdG and cotinine in smokers were significantly higher than that in non-smokers. Furthermore, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronide conjugate (defined as total NNAL) are the nitrosation metabolites of nicotine. In this study, urinary levels of 8-OHdG and cotinine were well correlated with urinary levels of total NNAL. This is also the first study to focus on the future risk of oxidative stress from exposure to cigarette smoke based on the relationship between 8-OHdG levels, cotinine levels, and total NNAL concentrations in the urine of humans. Graphical Abstract On-line SPE LC-MS/MS for the simultaneous determination of 8-OHdG and cotinine in human urine.

What causes human cancer? Approaches from the chemistry of DNA damage.

To prevent human cancers, environmental mutagens must be identified. A common mechanism of carcinogenesis is DNA damage, and thus it is quite possible that environmental mutagens can be trapped as adducts by DNA components. It is also important to identify new types of DNA damaging reactions and clarify their mechanisms. In this paper, I will provide typical examples of our efforts to identify DNA damage by environmental agents, from chemistry-based studies. 1) Oxidative DNA damage: 8-Hydroxydeoxyguanosine (8-OHdG, 8-oxodG) was discovered during a structural study of DNA modifications caused in vitro by heating glucose, which was used as a model of cooked foods. We found that various oxygen radical-forming agents induced the formation of 8-OHdG in DNA, in vitro and in vivo. Analyses of the urinary 8-OHdG levels are useful to assess the extent of oxidative DNA damage in a human population. 2) Lipid peroxide-derived DNA adducts: We searched for mutagens that react with deoxynucleosides, in model systems of lipid peroxidation. The reaction mixtures were analyzed by high performance liquid chromatography (HPLC), and we discovered various lipid peroxide-derived mutagens, including new mutagens. Some of these adducts were detected in human DNA. These mutagens may be involved in lipid peroxide-related cancers. 3) Methylation of cytosine by free radicals: Methylation of the cytosine C-5 position is an important mechanism of carcinogenesis, in addition to gene mutations. However, the actual mechanisms of de novo methylation in relation to environmental agents are not clear. We found that cytosine C-5 methylation occurred by a free radical mechanism. The possible role of this radical-induced DNA methylation in carcinogenesis will be discussed, in relation to the presently accepted concept of cancer epigenetics. In these studies, chemical analyses of the adducts formed in model reactions led to the discoveries of new mutagens and important types of DNA modifications, which seem to be involved in human carcinogenesis.

8-hydroxy-2′-deoxyguanosine (8-OHdG) biomarker detection down to picoMolar level on a plastic antibody film

An innovative biosensor assembly relying on a simple and straightforward in-situ construction is presented to monitor urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) down to the pmol/L level. The sensing film of the biosensor consisted of a molecularly imprinted polymer (MIP) layer for 8-OHdG assembled on a gold electrode through electropolymerization of monomer combined with the template.The analytical features of the resulting biosensor were assessed by Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). Some experimental parameters such as the initial concentration of the monomer and the ratio template-monomer were investigated and optimized in order to finely tune the performance of the MIP-based sensor. Under optimal conditions, the developed biosensor was able to rebind 8-OHdG with a linear response against EIS from 0.1 to 100pg/ml 3.5-3500 pM. The interference of coexisting species was tested, also with calibrations on urine samples, and good selectivity towards 8-OHdG was obtained.RAMAN spectroscopy, FTIR and SEM evaluations of the prepared films confirmed the formation of a polyphenol thin-film on the electrode surface. The presence and distribution of the imprinted cavities on the MIP layer was confirmed by confocal microscopy imaging of the film, after a post-treatment with Fluorescein Isothiocyanate (FITC) labeled 8-OHdG antibody.Overall, this label-free biosensor for urinary 8-OHdG detection constitutes a promising low-cost alternative to the conventional immunoassay approaches, due to its simplicity, stability, high sensitivity and selectivity for biological sample assays, opening new doors for other applications.

Oxidative stress and inflammation are associated with physical frailty in patients with Alzheimer's disease.

Dementia is closely connected with frailty, and these two conditions are common in older adults. However, the biological mechanism that causes frailty in patients with Alzheimer's disease (AD) is not fully understood. We determined whether oxidative stress and inflammatory mechanisms could be associated with physical frailty in patients with AD. We studied 140 elderly outpatients with mild-to-moderate AD. Frailty status was determined according to the presence of the following five measurable characteristics: weight loss, exhaustion, low physical activity, slowness and weakness. We measured oxidative stress markers, including plasma levels of diacron reactive oxygen metabolite and biological anti-oxidant potential, endogenous plasma anti-oxidants, such as albumin, bilirubin and uric acid, and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-epiPGF2α (8-isoprostane), and inflammatory markers, including interleukin-6 and tumor necrosis factor-α. Among patients, 44 (31%) were non-frail, 62 (44%) were prefrail and 34 (24%) were frail. Frail and prefrail patients were older, more likely to be women and had more comorbid medical conditions than non-frail patients. Frail or prefrail patients showed significantly higher diacron reactive oxygen metabolite and lower biological anti-oxidant potential levels, a significant decrease in bilirubin, a significant increase in urinary 8-OHdG and 8-isoprostane levels, and a significantly higher interleukin-6 level, in contrast to non-frail patients. Physical frailty is common in old and female AD patients with comorbid medical diseases. The present results strongly suggest that oxidative stress and inflammation are involved in the pathophysiology of frailty status in individuals with AD. Geriatr Gerontol Int 2017; 17: 913-918.

Effects of a supplement combining Pycnogenol® and l-arginine aspartate on lower urinary dysfunction compared with saw palmetto extract

ObjectivesLower urinary tract symptoms (LUTS) and sexual dysfunction (SDys) are common problems that affect quality of life (QOL) in elderly men. In addition to prescribed drugs, many over-the-counter medications including supplements are used to treat QOL diseases. Phosphodiesterase inhibitors are reported to be effective for both LUTS and SDys by increasing nitric oxide levels. French maritime pine bark extract Pycnogenol®, which is a potent nitric oxide donor, is reported to be effective for SDys. However, no reports have been published on whether it ameliorates LUTS. DesignOpen-labeled, randomized study. The effects of two supplements, Nokogiriyashi EX® containing 160 mg saw palmetto (SP) extract per tablet and Edicare® containing 10 mg of Pycnogenol®, 115 mg of l-arginine and 92 mg of aspartate (PAA) per tablet on International Prostate Symptom Score (IPSS), IPSS–QOL, Overactive Bladder Symptom Score (OABSS), International Index of Erectile Function 5 (IIEF5), Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF), urinary 8-OHdG and uroflowmetry (UFM) of total 40 men with LUTS and SDys were examined. Results19 subjects were instructed to take two tablets of SP, on the other 20 were on four tablets of PAA for 16 weeks. IPSS and IPSS–QOL showed statistically significant improvements in both groups. OABSS and IIEF5 were significantly improved in the PAA group. Conversely, ICIQ-SF, 8-OHdG and UFM did not change in either group. ConclusionsPAA might be an effective therapeutic alternative for elderly patients with LUTS and SDys.

The relationship between plasma and urinary 8-hydroxy-2-deoxyguanosine biomarkers measured by liquid chromatography tandem mass spectrometry.

Although 8-hydroxy-2-deoxyguanosine (8-OHdG) is a widely used promising biomarker of DNA damage, there are concerns about which tissues or body fluids should be sampled. The objective of this study is to evaluate the correlation of DNA oxidative damage biomarkers, 8-OHdG, between blood and urine and risk factors associated with 8OHdG. The study population was recruited from a baseline survey of a worksite lifestyle study including 92 office workers aged 23 to 60years. A self-administered questionnaire was used to collect information on personal characteristics. The plasma and urinary 8-OHdG was measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). In linear regression, a positive relation was found (p < 0.01) between the log-transformed plasma and urinary 8-OHdG levels adjusted for gender, age, BMI, and smoking status. Our findings showed that age, gender and smoking were significantly associated with plasma 8-OHdG, but not with urinary 8-OHdG. Our results suggest that there is a positive relation between the biomarkers of plasma (steady state DNA damage) and urinary 8-OHdG (total DNA damage). However, the plasma 8-OHdG is more sensitive than urinary 8-OHdG to detect increased oxidative damages induced by risk factors.

Chlorpyrifos exposure in farmers and urban adults: Metabolic characteristic, exposure estimation, and potential effect of oxidative damage

Chlorpyrifos is a widely used organophosphorus pesticide that efficiently protects crops against pests. However, recent studies suggest that severe exposure to chlorpyrifos may present adverse health effects in human. To analyze the exposure level and metabolic characteristics of chlorpyrifos pesticide in urban adults and farmers with/without occupation pesticide contact, the occurrence of urinary chlorpyrifos and methyl chlorpyrifos (CP-me), as well as their metabolite, 3,5,6-trichloro-2-pyridinol (TCPy), was determined in farmers of an agricultural village in China, and in urban adults of a nearby town. The geometric mean (GM) concentrations of TCPy, which is the major marker of chlorpyrifos exposure, were 4.29 and 7.57μg/g-creatinine in urban adults and farmers before pesticide application, respectively. Chlorpyrifos spraying significantly increased the concentrations of urinary TCPy. In the first day after spraying, a GM concentration of 43.7μg/g-creatinine was detected in the urine specimens from farmers, which decreased to 38.1 and 22.8μg/g-creatinine in the second and third day after chlorpyrifos spraying. The ratio of TCPy and its parent compounds, i.e. chlorpyrifos and CP-me, was positively associated with the sum concentration of urinary chlorpyrifos, CP-me, and TCPy, suggesting the increasing metabolic efficiency of chlorpyrifos to TCPy at higher chlorpyrifos exposure levels. To estimate the farmers’ occupational exposure to chlorpyrifos pesticide, a new model based on the fitted first-order elimination kinetics of TCPy was established. Occupational chlorpyrifos exposure in a farmer was estimated to be 3.70μg/kg-bw/day (GM), which is an exposure level that is higher than the recommended guideline levels. Significant increase of urinary 8-hydroxydeoxyguanosine (8-OHdG) was observed on the first day after chlorpyrifos spraying, which indicates a potential oxidative damage in farmers. However, urinary 8-OHdG returned to its baseline level within two days.

In vivo study of the renoprotective effects of EGCG in diabetic db/db mice

To explore the renoprotective effects of (-)-epigallocatechin-3-gallate (EGCG) and its potential mechanism in type 2 diabetic db/db mice. 8-week-old db/db mice (6 h fasting plasma glucose >16.7 mmol/L) were allocated randomly into Control group (non-intervention group, n=8), EGCG A group (50 mg·kg(-1)·d(-1,)n=8), EGCG B group (100 mg·kg(-1)·d(-1,)n=8). Before the study and after the intervention (in the 4(th)and 8(th)week), the body weight, the level of fasting plasma glucose, oral glucose tolerance test (OGTT) were measured and 24 h urine samples were collected. 24 h proteinuria was measured by routine chemical method. The levels of angiotensin Ⅱ(AngⅡ), fasting plasma insulin and urinary 8-OHdG were measured with enzyme-linked immunosorbent assay (ELISA). The protein expression levels of angiotensin Ⅱ type 1 receptor (AT-1R), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit P22-phox, NADPH oxidase subunit P47-phox, phospho-extracellular regulated protein kinases (p-Erk1/2), phospho-P38 mitogen-activated protein kinase (p-P38MAPK), phospho -phosphatidylinositol 3-hydroxy kinase (p-PI3K) and phospho-protein kinase B (p-AKT) were determined by Western blot. The renal pathological changes were examined by the method of PAS (periodic acid-Schiff stain). After 8 weeks of treatment with EGCG, the level of fasting plasma glucose decreased[(14.4±1.0) mmol/L, (14.2±0.7) mmol/L vs. (17.2±0.8) mmol/L]; the level of fasting plasma insulin increased[(13.2±1.2)mU/L, (13.4±1.3) mU/L vs. (9.9±1.0) mU/L]; the area under the curve (AUC) of OGTT decreased[(49.3±1.8) mmol·L(-1)·h(-1,)(44.8±0.7) mmol·L(-1)·h(-1)vs. (60.0±0.8) mmol·L(-1)·h(-1)]; the level of 24 h proteinuria[(8.8±1.0) mg, (8.6±1.1) mg vs. (11.7±1.3) mg]and urinary 8-OHdG[(90±5) ng/d, (78±5) ng/d vs. (118±10) ng/d]decreased; the level of serum Ang-Ⅱ[(498±23) ng/L, (511±19) ng/L vs. (688±17) ng/L]and renal cortex AngⅡ[(367±5) ng/L, (384±10) ng/L vs. (406±7) ng/L]decreased; the expression levels of AT-1R, P22-phox, P47-phox, p-Erk1/2, p-P38MAPK downregulated obviously and the expression levels of p-PI3K, p-AKT increased significantly (P<0.05), and renal pathology improved as compared with the control group. After 8 weeks of treatment with EGCG, the level of urinary 8-OHdG decreased (P=0.007) and the AUC of OGTT also decreased (P=0.01) in EGCG B group when compared with the EGCG A group. EGCG protects the kidney in diabetic db/db mice via anti-oxidative stress pathway, as well as inhibiting Erk1/2-P38MAPK pathway and improving PI3K-AKT signaling transduction pathway.

Specific histone modification responds to arsenic-induced oxidative stress

To explore whether specific histone modifications are associated with arsenic-induced oxidative damage, we recruited 138 arsenic-exposed and arsenicosis subjects from Jiaole Village, Xinren County of Guizhou province, China where the residents were exposed to arsenic from indoor coal burning. 77 villagers from Shang Batian Village that were not exposed to high arsenic coal served as the control group. The concentrations of urine and hair arsenic in the arsenic-exposure group were 2.4-fold and 2.1-fold (all P<0.001) higher, respectively, than those of the control group. Global histone modifications in human peripheral lymphocytes (PBLCs) were examined by ELISA. The results showed that altered global levels of H3K18ac, H3K9me2, and H3K36me3 correlated with both urinary and hair-arsenic levels of the subjects. Notably, H3K36me3 and H3K18ac modifications were associated with urinary 8-OHdG (H3K36me3: β=0.16; P=0.042, H3K18ac: β=−0.24; P=0.001). We also found that the modifications of H3K18ac and H3K36me3 were enriched in the promoters of oxidative stress response (OSR) genes in human embryonic kidney (HEK) cells and HaCaT cells, providing evidence that H3K18ac and H3K36me3 modifications mediate transcriptional regulation of OSR genes in response to NaAsO2 treatment. Particularly, we found that reduced H3K18ac modification correlated with suppressed expression of OSR genes in HEK cells with long term arsenic treatment and in PBLCs of all the subjects. Taken together, we reveal a critical role for specific histone modification in response to arsenic-induced oxidative damage.

Correlation between markers of DNA and lipid oxidative damage in maternal and fetoplacental compartment in the mid-trimester of pregnancy.

To determine the levels of 8-isoprostane (8-IP) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine and in amniotic fluid (AF) of pregnant women and to assess the correlation between oxidative status in the maternal and fetal compartment in the second trimester of pregnancy. One hundred and forty-six women with singleton pregnancies, undergoing amniocentesis at the Department of Obstetrics and Gynaecology at the University Medical Centre Ljubljana, were prospectively enrolled. AF and maternal urine were collected in the second trimester of pregnancy. Paired urinary and AF 8-IP and 8-OHdG were measured and evaluated cross-sectionally. 8-IP and 8-OHdG concentrations were higher in maternal urine compared to AF and the ratios were 47:1 and 50:1, respectively. AF 8-OHdG was very low and in 74% was below the limit of detection (LOD). We found a positive correlation between 8-IP in maternal and fetal compartment (ρ=0.217, P=0.008), which stayed unchanged also after adjustment for possible confounding factors. Oxidative damage to lipids and DNA is also a part of physiologic processes during healthy pregnancy. 8-IP and 8-OHdG are constantly present in urine and AF. A weak positive correlation between maternal and fetal unit suggests a weak reflection of fetal oxidative status in maternal urine in the mid-trimester.

The Omega-3 Index Is Inversely Associated with Depressive Symptoms among Individuals with Elevated Oxidative Stress Biomarkers

Background: Omega-3 (n–3) fatty acid (FA) consumption is thought to improve depressive symptoms. However, current evidence is limited, and whether this association exists among Puerto Ricans, a population burdened by depression, remains uncertain.Objectives: We examined the association between ω-3 FA biomarkers and depressive symptoms as well as the potential influence of oxidative stress.Methods: Baseline and longitudinal analyses were conducted in the Boston Puerto Rican Health Study (n = 787; participants aged 57 ± 0.52 y, 73% women). Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) concentration, a measure of oxidative stress, and erythrocyte FA composition were collected at baseline. We calculated the omega-3 index as the sum of eicosapentaenoic and docosahexaenoic acids, expressed as a percentage of total FAs. Baseline and 2-y depressive symptoms were characterized by using the Center for Epidemiological Studies–Depression Scale (CES-D). Statistical analyses included linear and logistic regression.Results: Urinary 8-OHdG concentration tended to modify the relation between the erythrocyte omega-3 index and baseline CES-D score (P-interaction = 0.10). In stratified analyses, the omega-3 index was inversely associated with CES-D score (β = −1.74, SE = 0.88; P = 0.02) among those in the top quartile of 8-OHdG concentration but not among those in the lower quartiles. The relation between the omega-3 index and CES-D at 2 y was more clearly modified by 8-OHdG concentration (P-interaction = 0.04), where the omega-3 index was inversely associated with CES-D at 2 y, adjusted for baseline (β = −1.66, SE = 0.66; P = 0.02), only among those with elevated 8-OHdG concentrations. Among individuals not taking antidepressant medications and in the top tertile of urinary 8-OHdG concentration, the omega-3 index was associated with significantly lower odds of a CES-D score ≥16 at baseline (OR: 0.72; 95% CI: 0.53, 0.96) but not at 2 y (OR: 0.83; 95% CI: 0.60, 1.15).Conclusions: An inverse association between the omega-3 index and depressive symptoms was observed among participants with elevated oxidative stress biomarkers. These data suggest that oxidative stress status may identify those who might benefit from ω-3 FA consumption to improve depressive symptoms.

Urinary Concentrations of Bisphenols and Their Association with Biomarkers of Oxidative Stress in People Living Near E-Waste Recycling Facilities in China.

In this study, concentrations of bisphenol A (BPA) and seven other bisphenols (BPs) were measured in urine samples collected from people living in and around e-waste dismantling facilities, and in matched reference population from rural and urban areas in China. BPA, bisphenol S (BPS), and bisphenol F (BPF) were frequently detected (detection frequencies: > 90%) in urine samples collected from individuals who live near e-waste facilities, with geometric mean (GM) concentrations of 2.99 (or 3.75), 0.361 (or 0.469), and 0.349 (or 0.435) ng/mL (or μg/g Cre), respectively; the other five BPs were rarely found in urine samples, regardless of the sampling location. The urinary concentrations of BPA and BPF, but not BPS, were significantly higher in individuals from e-waste recycling locations than did individuals from a rural reference location. Our findings indicated that e-waste dismantling activities contribute to human exposure to BPA and BPF. 8-Hydroxy-2'-deoxyguanosine (8-OHdG) was measured in urine as a marker of oxidative stress. In the e-waste dismantling location, urinary 8-OHdG was significantly and positively correlated (p < 0.001) with urinary BPA and BPS, but not BPF; a similar correlation was also observed in reference sites. These findings suggest that BPA and BPS exposures are associated with elevated oxidative stress.

Arsenic projects in SE Asia.

Early life exposure to inorganic arsenic is associated with a wide range of malignant and chronic disease outcomes in humans. Prenatal arsenic exposure may give rise to adverse effects on child health and development as arsenic readily passes through the placenta in human beings. The impact of maternal arsenic exposure on fetal gene expression was conducted in pregnant women living in Southern Thailand. Arsenic exposed newborns had significantly higher levels of arsenic in cord blood, and a set of genes associated with numerous biological pathways, including cell signaling, apoptosis, inflammatory and stress response. A slight increase in promoter methylation of p53 in cord blood lymphocytes which correlated with arsenic accumulation in nails was observed in these exposed newborns. A follow-up study on these exposed children showed a significant increase in oxidative DNA damage, measured as 8-hydroxydeoxyguanosine (8-OHdG) in saliva. In addition, levels of urinary 8-OHdG excretion and salivary hOGG1 expression were significantly decreased in exposed children suggesting a defect in repair of 8-OHdG in arsenic-exposed children. Our study indicates that prenatal arsenic and continued exposure through early childhood can trigger various genetic and epigenetic alterations that may lead to disease development later in life.

Simultaneous determination of urinary parabens, bisphenol A, triclosan, and 8-hydroxy-2'-deoxyguanosine by liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

A simple and fast method was developed for the simultaneous determination of five parabens, bisphenol A (BPA), triclosan (TCS), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in human urine using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The solid-phase extraction (SPE) procedure, chromatographic conditions, and MS/MS parameters were optimized to achieve maximum sensitivity and accuracy for the analytes. The validation results showed that the correlation coefficients (R (2)) and recoveries ranged from 0.999 to 1 and 83.9 to 109.9%, respectively, and the intra-day and inter-day precisions (relative standard deviation, RSD) were within the range of 1.3-8.5% and 1.3-9.0%, respectively. The limits of detection for the analytes ranged from 0.001 to 0.05μg/L. The method was successfully employed to determine parabens, BPA, TCS, and 8-OHdG in urine samples from school students in Guangzhou, China. The results showed that methyl, ethyl, n-propyl parabens, BPA, TCS, and 8-OHdG were frequently detected in urine samples. n-Butyl and benzyl parabens were only detected in a part of the samples due to their low concentrations in urine.

Linking mobile source-PAHs and biological effects in traffic police officers and drivers in Rawalpindi (Pakistan)

The aim of this study was to evaluate the effect of traffic related polycyclic aromatic hydrocarbons (PAHs) on blood parameters of subjects, including traffic police officers (TP), drivers (DR) and control subjects (CN) with presumably different levels of exposure. We quantified the urinary 1-hydroxypyrene (1-OHPyr), α-naphthol and β-naphthol (α- and β-naph) as biomarkers of exposure to PAHs in relation with biomarkers of effect (Hb, MCV, PCV, PLT, RBCs), biomarkers of inflammation/infection (CRP, WBCs), oxidative stress (SOD) and oxidative DNA damage i.e. 8-hydroxy-2-deoxyguanosine (8-OHdG). Results showed that mean 1-OHPyr, α-naph and β-naph concentrations were significantly higher in TPs (0.98, 1.55, and 1.9µmolmol-Cr−1, respectively, p<0.05) than CNs (0.7, 0.6; 0.67µmolmol-Cr−1, respectively, P<0.05). Furthermore, WBC and CRP were found in higher concentrations in TPs than CNs (7.04×103µL−1 and 0.95mgL−1 vs. 5.1×103µL−1 and 0.54mgL−1, respectively). The urinary 8-OHdG level, a biomarker of oxidative DNA damage, was higher in TPs than both CN and DR subjects (48ngmg-Cr−1, 24ngmg-Cr−1 and 33ngmg-Cr−1, respectively). Self-reported health assessment indicates that, on the basis of daily time spent in the middle of heavy traffic, TPs and DRs more frequently suffered from adverse head and respiratory symptoms. The PCA analysis evidenced the impact of traffic pollution on exposure biomarkers and DNA damage. The study suggests that traffic pollution may be associated with important health risk, in particular on the respiratory system, not only for workers exposed to traffic exhausts but also for general public. Finally, vehicular air pollution in the city of Rawalpindi should be a high-priority concern for the Pakistan Government that needs to be addressed.