| 1. |
- Ameer, Syeda Shegufta, et al.
(författare)
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Arsenic exposure from drinking water is associated with decreased gene expression and increased DNA methylation in peripheral blood
- 2017
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Ingår i: Toxicology and Applied Pharmacology. - : Elsevier BV. - 0041-008X .- 1096-0333. ; 321, s. 57-66
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Tidskriftsartikel (refereegranskat)abstract
- Background Exposure to inorganic arsenic increases the risk of cancer and non-malignant diseases. Inefficient arsenic metabolism is a marker for susceptibility to arsenic toxicity. Arsenic may alter gene expression, possibly by altering DNA methylation. Objectives To elucidate the associations between arsenic exposure, gene expression, and DNA methylation in peripheral blood, and the modifying effects of arsenic metabolism. Methods The study participants, women from the Andes, Argentina, were exposed to arsenic via drinking water. Arsenic exposure was assessed as the sum of arsenic metabolites in urine (U-As), using high performance liquid-chromatography hydride-generation inductively-coupled-plasma-mass-spectrometry, and arsenic metabolism efficiency was assessed by the urinary fractions (%) of the individual metabolites. Genome-wide gene expression (N = 80 women) and DNA methylation (N = 93; 80 overlapping with gene expression) in peripheral blood were measured using Illumina DirectHyb HumanHT-12 v4.0 and Infinium Human-Methylation 450K BeadChip, respectively. Results U-As concentrations, ranging 10–1251 μg/L, was associated with decreased gene expression: 64% of the top 1000 differentially expressed genes were down-regulated with increasing U-As. U-As was also associated with hypermethylation: 87% of the top 1000 CpGs were hypermethylated with increasing U-As. The expression of six genes and six individual CpG sites were significantly associated with increased U-As concentration. Pathway analyses revealed enrichment of genes related to cell death and cancer. The pathways differed somewhat depending on arsenic metabolism efficiency. We found no overlap between arsenic-related gene expression and DNA methylation for individual genes. Conclusions Increased arsenic exposure was associated with lower gene expression and hypermethylation in peripheral blood, but with no evident overlap.
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| 2. |
- Barregård, Lars, 1948, et al.
(författare)
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Human and Methodological Sources of Variability in the Measurement of Urinary 8-Oxo-7,8-dihydro-2 '-deoxyguanosine
- 2013
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Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 18:18, s. 2377-2391
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) is a widely used biomarker of oxidative stress. However, variability between chromatographic and ELISA methods hampers interpretation of data, and this variability may increase should urine composition differ between individuals, leading to assay interference. Furthermore, optimal urine sampling conditions are not well defined. We performed inter-laboratory comparisons of 8-oxodG measurement between mass spectrometric-, electrochemical- and ELISA-based methods, using common within-technique calibrants to analyze 8-oxodG-spiked phosphate-buffered saline and urine samples. We also investigated human subject- and sample collection-related variables, as potential sources of variability. Results: Chromatographic assays showed high agreement across urines from different subjects, whereas ELISAs showed far more inter-laboratory variation and generally overestimated levels, compared to the chromatographic assays. Excretion rates in timed 'spot' samples showed strong correlations with 24 h excretion (the 'gold' standard) of urinary 8-oxodG (r(p) 0.67-0.90), although the associations were weaker for 8-oxodG adjusted for creatinine or specific gravity (SG). The within-individual excretion of 8-oxodG varied only moderately between days (CV 17% for 24 h excretion and 20% for first void, creatinine-corrected samples). Innovation: This is the first comprehensive study of both human and methodological factors influencing 8-oxodG measurement, providing key information for future studies with this important biomarker. Conclusion: ELISA variability is greater than chromatographic assay variability, and cannot determine absolute levels of 8-oxodG. Use of standardized calibrants greatly improves intra-technique agreement and, for the chromatographic assays, importantly allows integration of results for pooled analyses. If 24 h samples are not feasible, creatinine- or SG-adjusted first morning samples are recommended.
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| 3. |
- ElBeck, Zaher, et al.
(författare)
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Epigenetic modulators link mitochondrial redox homeostasis to cardiac function in a sex-dependent manner
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- While excessive production of reactive oxygen species (ROS) is a characteristic hallmark of numerous diseases, clinical approaches that ameliorate oxidative stress have been unsuccessful. Here, utilizing multi-omics, we demonstrate that in cardiomyocytes, mitochondrial isocitrate dehydrogenase (IDH2) constitutes a major antioxidative defense mechanism. Paradoxically reduced expression of IDH2 associated with ventricular eccentric hypertrophy is counterbalanced by an increase in the enzyme activity. We unveil redox-dependent sex dimorphism, and extensive mutual regulation of the antioxidative activities of IDH2 and NRF2 by a feedforward network that involves 2-oxoglutarate and L-2-hydroxyglutarate and mediated in part through unconventional hydroxy-methylation of cytosine residues present in introns. Consequently, conditional targeting of ROS in a murine model of heart failure improves cardiac function in sex- and phenotype-dependent manners. Together, these insights may explain why previous attempts to treat heart failure with antioxidants have been unsuccessful and open new approaches to personalizing and, thereby, improving such treatment.
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| 4. |
- Eneroth, Hanna, et al.
(författare)
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Duration of exclusive breast-feeding and infant iron and zinc status in rural Bangladesh
- 2009
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Ingår i: Journal of Nutrition. - : Elsevier BV. - 0022-3166 .- 1541-6100. ; 139:8, s. 1562-1567
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Tidskriftsartikel (refereegranskat)abstract
- There is a concern that exclusive breast-feeding (EBF) for 6 mo may lead to iron and zinc deficiency in low-birth weight (LBW) infants. We assessed the association between duration of EBF and infant iron and zinc status in the Maternal and Infant Nutrition Interventions in Matlab trial, Bangladesh, stratified for normal birth weigh (NBW) and LBW. Duration of EBF was classified into EBF <4 mo and EBF 4-6 mo based on monthly recalls of foods introduced to the infant. Blood samples collected at 6 mo were analyzed for plasma zinc (n = 1032), plasma ferritin (n = 1040), and hemoglobin (Hb) (n = 791). Infants EBF 4-6 mo had a higher mean plasma zinc concentration (9.9 +/- 2.3 micromol/L) than infants EBF <4mo (9.5 +/- 2.0 micromol/L) (P < 0.01). This association was apparent in only the NBW strata and was not reflected in a lower prevalence of zinc deficiency. Duration of EBF was not associated with concentration of plasma ferritin, Hb concentration, or prevalence of iron deficiency or anemia in any strata. Regardless of EBF duration, the prevalence of zinc deficiency, iron deficiency, and anemia was high in infants in this population and strategies to prevent deficiency are needed.
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| 5. |
- Eneroth, Hanna, et al.
(författare)
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Maternal multiple micronutrient supplementation has limited impact on micronutrient status of Bangladeshi infants compared with standard iron and folic acid supplementation
- 2010
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Ingår i: Journal of Nutrition. - : Elsevier BV. - 0022-3166 .- 1541-6100. ; 140:3, s. 618-624
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge about the impact of maternal food and micronutrient supplementation on infant micronutrient status is limited. We examined the effect of maternal food and micronutrient supplementation on infant micronutrient status in the Maternal and Infant Nutrition Interventions in Matlab Trial. Pregnant women (n = 4436) were randomized to Early or Usual promotion of enrollment in a food supplementation program. In addition, they were randomly allocated to 1 of the following 3 types of daily micronutrient supplements provided from wk 14 of gestation to 3 mo postpartum: 1) folic acid and 30 mg iron (Fe30Fol); 2) folic acid and 60 mg iron; or 3) a multiple micronutrient including folic acid and 30 mg iron (MMS). At 6 mo, infant blood samples (n = 1066) were collected and analyzed for hemoglobin and plasma ferritin, zinc, retinol, vitamin B-12, and folate. The vitamin B-12 concentration differed between the micronutrient supplementation groups (P = 0.049). The prevalence of vitamin B-12 deficiency was lower in the MMS group (26.1%) than in the Fe30Fol group (36.5%) (P = 0.003). The prevalence of zinc deficiency was lower in the Usual food supplementation group (54.1%) than in the Early group (60.2%) (P = 0.046). There were no other differential effects according to food or micronutrient supplementation groups. We conclude that maternal multiple micronutrient supplementation may have a beneficial effect on vitamin B-12 status in infancy.
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| 6. |
- Engström, Karin, et al.
(författare)
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Efficient Arsenic Metabolism - The AS3MT Haplotype Is Associated with DNA Methylation and Expression of Multiple Genes Around AS3MT.
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Arsenic is a very potent toxicant. One major susceptibility factor for arsenic-related toxicity is the efficiency of arsenic metabolism. The efficiency, in turn, is associated with non-coding single nucleotide polymorphisms (SNPs) in the arsenic methyltransferase AS3MT on chromosome 10q24. However, the mechanism of action for these SNPs is not yet clarified. Here, we assessed the influence of genetic variation in AS3MT on DNA methylation and gene expression within 10q24, in people exposed to arsenic in drinking water. DNA was extracted from peripheral blood from women in the Argentinean Andes (N = 103) and from cord blood from new-borns in Bangladesh (N = 127). AS3MT SNPs were analyzed with Sequenom or Taqman assays. Whole genome epigenetic analysis with Infinium HumanMethylation450 BeadChip was performed on bisulphite-treated DNA. Whole genome gene expression analysis was performed with Illumina DirectHyb HumanHT-12 v4.0 on RNA from peripheral blood. Arsenic exposure was assessed by HPLC-ICPMS. In the Argentinean women, the major AS3MT haplotype, associated with more efficient arsenic metabolism, showed increased methylation of AS3MT (p = 10(-6)) and also differential methylation of several other genes within about 800 kilobasepairs: CNNM2 (p<10(-16)), NT5C2 (p<10(-16)), C10orf26 (p = 10(-8)), USMG5 (p = 10(-5)), TRIM8 (p = 10(-4)), and CALHM2 (p = 0.038) (adjusted for multiple comparisons). Similar, but weaker, associations between AS3MT haplotype and DNA methylation in 10q24 were observed in cord blood (Bangladesh). The haplotype-associated altered CpG methylation was correlated with reduced expression of AS3MT and CNNM2 (r(s) = -0.22 to -0.54), and with increased expression of NT5C2 and USMG5 (r(s) = 0.25 to 0.58). Taking other possibly influential variables into account in multivariable linear models did only to a minor extent alter the strength of the associations. In conclusion, the AS3MT haplotype status strongly predicted DNA methylation and gene expression of AS3MT as well as several genes in 10q24. This raises the possibility that several genes in this region are important for arsenic metabolism.
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| 7. |
- Hoppe, Michael, 1969, et al.
(författare)
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Hepcidin, interleukin-6 and hematological iron markers in males before and after heart surgery : Prohepcidin and hepcidin pre- and postoperative
- 2009
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Ingår i: Journal of Nutritional Biochemistry. - 0955-2863. ; 20:1, s. 11-16
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Tidskriftsartikel (refereegranskat)abstract
- Anemia of inflammation in patients with acute or chronic acute-phase activation is a common clinical problem. Hepcidin is a peptide shown to be the principal regulator of the absorption and systemic distribution of iron. Main inducers of hepcidin are iron overload, hypoxia and inflammation, where the latter has been linked to hepcidin via increased interleukin-6 (IL-6). This article addresses the impact and time course of postoperative acute-phase reaction in humans following heart surgery on prohepcidin, hepcidin, hematological markers and IL-6 concentrations. Serum concentrations of prohepcidin, hepcidin, IL-6 and hematological iron parameters were studied in five male patients without infection before and after heart surgery. This study, which is the first to report the impact on serum hepcidin and serum prohepcidin concentrations in patients following surgery, clearly demonstrates the induction of hypoferremia due to the postoperative acute-phase reaction. Significant changes were seen for serum iron concentration, transferrin saturation, total iron binding capacity and hemoglobin concentration. A significant increase in ferritin concentration was seen 96-144 h postoperatively. Additionally, there were significant alterations in both serum hepcidin after 96-144 h and serum prohepcidin after 48 h compared with preoperative values. Serum prohepcidin decreased, whereas serum hepcidin increased. In conclusion, changes in serum prohepcidin were followed by an increase in serum hepcidin. This speaks in favor of a chain of action where proteolytic trimming of serum prohepcidin results in increased serum hepcidin. However, hypoferremia appeared prior to the changes in serum prohepcidin and serum hepcidin.
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| 8. |
- Hossain, Bakhtiar, et al.
(författare)
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Environmental arsenic exposure and DNA methylation of the tumor suppressor gene p16 and the DNA repair gene MLH1: effect of arsenic metabolism and genotype.
- 2012
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Ingår i: Metallomics. - : Oxford University Press (OUP). - 1756-5901 .- 1756-591X. ; 4:11, s. 1167-1175
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Tidskriftsartikel (refereegranskat)abstract
- Arsenic is carcinogenic, possibly partly through epigenetic mechanisms. We evaluated the effects of arsenic exposure and metabolism on DNA methylation. Arsenic exposure and methylation efficiency in 202 women in the Argentinean Andes were assessed from concentrations of arsenic metabolites in urine (inorganic arsenic, methylarsonic acid [MMA], and dimethylarsinic acid [DMA]), measured by HPLC-ICPMS. Methylation of CpGs of the tumor suppressor gene p16, the DNA repair gene MLH1, and the repetitive elements LINE1 was measured by PCR pyrosequencing of blood DNA. Genotyping (N = 172) for AS3MT was performed using Sequenom™, and gene expression (N = 90) using Illumina DirectHyb HumanHT-12 v3.0. Median arsenic concentration in urine was 230 μg L(-1) (range 10.1-1251). In linear regression analysis, log(2)-transformed urinary arsenic concentrations were positively associated with methylation of p16 (β = 0.14, P = 0.0028) and MLH1 (β = 0.28, P = 0.0011), but not with LINE1. Arsenic concentrations were of borderline significance negatively correlated with expression of p16 (r(s) = -0.20; P = 0.066)), but not with MLH1. The fraction of inorganic arsenic was positively (β = 0.026; P = 0.010) and DMA was negatively (β = -0.017, P = 0.043) associated with p16 methylation with no effect of MMA. Carriers of the slow-metabolizing AS3MT haplotype were associated with more p16 methylation (P = 0.022). Arsenic exposure was correlated with increased methylation, in blood, of genes encoding enzymes that suppress carcinogenesis, and the arsenic metabolism efficiency modified the degree of epigenetic alterations.
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| 9. |
- Hossain, Bakhtiar, et al.
(författare)
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Exposure to welding fumes is associated with hypomethylation of the F2RL3 gene: a cardiovascular disease marker.
- 2015
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Ingår i: Occupational and Environmental Medicine. - : BMJ. - 1470-7926 .- 1351-0711. ; 72:12, s. 845-851
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Tidskriftsartikel (refereegranskat)abstract
- Welders are at risk for cardiovascular disease. Recent studies linked tobacco smoke exposure to hypomethylation of the F2RL3 (coagulation factor II (thrombin) receptor-like 3) gene, a marker for cardiovascular disease prognosis and mortality. However, whether welding fumes cause hypomethylation of F2RL3 remains unknown.
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| 10. |
- Hossain, Mohammad Bakhtiar, et al.
(författare)
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Cadmium, mercury, and lead in kidney cortex are not associated with urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in living kidney donors.
- 2014
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Ingår i: International archives of occupational and environmental health. - : Springer Science and Business Media LLC. - 1432-1246 .- 0340-0131. ; 87:3, s. 315-322
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Cadmium in urine is positively associated with urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) concentrations, a sensitive marker of oxidative DNA damage. We determined whether kidney concentrations of cadmium, mercury, and lead, which may generate oxidative DNA damage, were associated with urinary 8-oxodG or not. METHODS: 8-OxodG was measured in separate 24h and overnight urine samples from Swedish healthy adult kidney donors (N=152) using LC-MS/MS. Concentrations of metals were measured in kidney biopsies (N=109) by ICP-MS. RESULTS: The median 8-oxodG concentrations (adjusted to specific gravity) in 24h and overnight samples were 13.5 and 15.3nmol/L; 8-oxodG excretion rates in 24h and overnight samples were 0.93 and 0.86nmol/h. In multivariable linear regression analyses, we did not find any association between 8-oxodG concentrations or rates and elements in the kidney. The 24-h 8-oxodG concentrations were positively associated with serum ferritin (β=0.048, p<0.0001), body weight (β=0.13, p=0.0019), and inversely with gender (β=-3.34, p=0.0024). Similar associations with 8-oxodG excretion rates were stronger. Smoking was positively associated with 24-h 8-oxodG excretion rates (β=0.26, p=0.0090), but not with overnight samples. CONCLUSIONS: Neither cadmium, nor mercury or lead in the kidney contributed to urinary 8-oxodG concentrations in non-occupationally exposed subjects. The iron status was positively associated with urinary 8-oxodG, particularly in women.
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