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Tamayo LI, Haque SE, Islam T, Ahmed A, Rahman M, Horayra A, Tong L, Chen L, Martinez-Cardoso A, Ahsan H, Pierce BL. Returning personal genetic information on susceptibility to arsenic toxicity to research participants in Bangladesh. ENVIRONMENTAL RESEARCH 2024; 240:117482. [PMID: 37879393 PMCID: PMC10842833 DOI: 10.1016/j.envres.2023.117482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/13/2023] [Accepted: 10/22/2023] [Indexed: 10/27/2023]
Abstract
BACKGROUND There is growing consensus that researchers should offer to return genetic results to participants, but returning results in lower-resource countries has received little attention. In this study, we return results on genetic susceptibility to arsenic toxicity to participants in a Bangladeshi cohort exposed to arsenic through naturally-contaminated drinking water. We examine the impact on behavioral changes related to exposure reduction. METHODS We enrolled participants from the Health Effects of Arsenic Longitudinal Study who had (1) high arsenic (≥150 μg/g creatinine) in a recent urine sample and (2) existing data on genetic variants impacting arsenic metabolism efficiency (AS3MT and FTCD). We used genetic data to recruit three study groups, each with n = 103: (1) efficient metabolizers (low-risk), (2) inefficient metabolizers (high-risk), and (3) a randomly-selected control group (NCT05072132). At baseline, all participants received information on the effects of arsenic and how to reduce exposure by switching to a low arsenic well. The two intervention groups also received their arsenic metabolism efficiency status (based on their genetic results). Changes in behavior and arsenic exposure were assessed using questionnaires and urine arsenic measures after six months. RESULTS Clear decreases in urine arsenic after six months were observed for all three groups. The inefficient group self-reported higher levels of attempted switching to lower arsenic wells than the other groups; however, there was no detectable difference in urine arsenic reduction among the three groups. Participants showed strong interest in receiving genetic results and found them useful. The inefficient group experienced higher levels of anxiety than the other groups. Among the efficient group, that receiving genetic results did not appear to hinder behavioral change. CONCLUSION Returning genetic results increased self-reported exposure-reducing behaviors but did not have a detectable impact on reducing urine arsenic over and above a one-on-one educational intervention.
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Affiliation(s)
- Lizeth I Tamayo
- Department of Public Health Sciences, University of Chicago, Chicago, IL, 60615, USA
| | | | - Tariqul Islam
- University of Chicago Research Bangladesh, Dhaka, Bangladesh
| | - Alauddin Ahmed
- University of Chicago Research Bangladesh, Dhaka, Bangladesh
| | - Moziber Rahman
- University of Chicago Research Bangladesh, Dhaka, Bangladesh
| | - Abu Horayra
- University of Chicago Research Bangladesh, Dhaka, Bangladesh
| | - Lin Tong
- Department of Public Health Sciences, University of Chicago, Chicago, IL, 60615, USA
| | - Lin Chen
- Department of Public Health Sciences, University of Chicago, Chicago, IL, 60615, USA
| | | | - Habibul Ahsan
- Department of Public Health Sciences, University of Chicago, Chicago, IL, 60615, USA; Department of Human Genetics, University of Chicago, Chicago, IL, 60615, USA; Department of Medicine, University of Chicago, Chicago, IL, 60615, USA
| | - Brandon L Pierce
- Department of Public Health Sciences, University of Chicago, Chicago, IL, 60615, USA; Department of Human Genetics, University of Chicago, Chicago, IL, 60615, USA; Comprehensive Cancer Center, University of Chicago, Chicago, IL, 60615, USA.
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Douillet C, Miller M, Cable PH, Shi Q, El-Masri H, Matoušek T, Koller BH, Thomas DJ, Stýblo M. Fate of arsenicals in mice carrying the human AS3MT gene exposed to environmentally relevant levels of arsenite in drinking water. Sci Rep 2023; 13:3660. [PMID: 36871058 PMCID: PMC9985638 DOI: 10.1038/s41598-023-30723-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
Although mice are widely used to study adverse effects of inorganic arsenic (iAs), higher rates of iAs methylation in mice than in humans may limit their utility as a model organism. A recently created 129S6 mouse strain in which the Borcs7/As3mt locus replaces the human BORCS7/AS3MT locus exhibits a human-like pattern of iAs metabolism. Here, we evaluate dosage dependency of iAs metabolism in humanized (Hs) mice. We determined tissue and urinary concentrations and proportions of iAs, methylarsenic (MAs), and dimethylarsenic (DMAs) in male and female Hs and wild-type (WT) mice that received 25- or 400-ppb iAs in drinking water. At both exposure levels, Hs mice excrete less total arsenic (tAs) in urine and retain more tAs in tissues than WT mice. Tissue tAs levels are higher in Hs females than in Hs males, particularly after exposure to 400-ppb iAs. Tissue and urinary fractions of tAs present as iAs and MAs are significantly greater in Hs mice than in WT mice. Notably, tissue tAs dosimetry in Hs mice resembles human tissue dosimetry predicted by a physiologically based pharmacokinetic model. These data provide additional support for use of Hs mice in laboratory studies examining effects of iAs exposure in target tissues or cells.
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Affiliation(s)
- Christelle Douillet
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7461, USA
| | - Madison Miller
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7461, USA
| | - Peter H Cable
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7461, USA
| | - Qing Shi
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7461, USA
| | - Hisham El-Masri
- Chemical Characterization and Exposure Division, Center for Computational Toxicology & Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27709, USA
| | - Tomáš Matoušek
- Institute of Analytical Chemistry of the Czech Academy of Sciences, v. v. i., Veveří 97, 602 00, Brno, Czech Republic
| | - Beverly H Koller
- Department of Genetics, School of Medicine, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - David J Thomas
- Dinkey Creek Consulting, LLC, Chapel Hill, NC, 27517, USA
| | - Miroslav Stýblo
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7461, USA.
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Chernoff MB, Delgado D, Tong L, Chen L, Oliva M, Tamayo LI, Best LG, Cole S, Jasmine F, Kibriya MG, Nelson H, Huang L, Haack K, Kent J, Umans JG, Graziano J, Navas-Acien A, Karagas MR, Ahsan H, Pierce BL. Sequencing-based fine-mapping and in silico functional characterization of the 10q24.32 arsenic metabolism efficiency locus across multiple arsenic-exposed populations. PLoS Genet 2023; 19:e1010588. [PMID: 36668670 PMCID: PMC9891528 DOI: 10.1371/journal.pgen.1010588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 02/01/2023] [Accepted: 12/20/2022] [Indexed: 01/22/2023] Open
Abstract
Inorganic arsenic is highly toxic and carcinogenic to humans. Exposed individuals vary in their ability to metabolize arsenic, and variability in arsenic metabolism efficiency (AME) is associated with risks of arsenic-related toxicities. Inherited genetic variation in the 10q24.32 region, near the arsenic methyltransferase (AS3MT) gene, is associated with urine-based measures of AME in multiple arsenic-exposed populations. To identify potential causal variants in this region, we applied fine mapping approaches to targeted sequencing data generated for exposed individuals from Bangladeshi, American Indian, and European American populations (n = 2,357, 557, and 648 respectively). We identified three independent association signals for Bangladeshis, two for American Indians, and one for European Americans. The size of the confidence sets for each signal varied from 4 to 85 variants. There was one signal shared across all three populations, represented by the same SNP in American Indians and European Americans (rs191177668) and in strong linkage disequilibrium (LD) with a lead SNP in Bangladesh (rs145537350). Beyond this shared signal, differences in LD patterns, minor allele frequency (MAF) (e.g., rs12573221 ~13% in Bangladesh ~0.2% among American Indians), and/or heterogeneity in effect sizes across populations likely contributed to the apparent population specificity of the additional identified signals. One of our potential causal variants influences AS3MT expression and nearby DNA methylation in numerous GTEx tissue types (with rs4919690 as a likely causal variant). Several SNPs in our confidence sets overlap transcription factor binding sites and cis-regulatory elements (from ENCODE). Taken together, our analyses reveal multiple potential causal variants in the 10q24.32 region influencing AME, including a variant shared across populations, and elucidate potential biological mechanisms underlying the impact of genetic variation on AME.
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Affiliation(s)
- Meytal Batya Chernoff
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois, United States of America
- Interdisciplinary Scientist Training Program, University of Chicago, Chicago, Illinois, United States of America
- University of Chicago Pritzker School of Medicine, Chicago, Illinois, United States of America
| | - Dayana Delgado
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois, United States of America
| | - Lin Tong
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois, United States of America
| | - Lin Chen
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois, United States of America
| | - Meritxell Oliva
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois, United States of America
| | - Lizeth I. Tamayo
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois, United States of America
| | - Lyle G. Best
- Missouri Breaks Industries Research Inc, Eagle Butte, South Dakota, United States of America
| | - Shelley Cole
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Farzana Jasmine
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois, United States of America
| | - Muhammad G. Kibriya
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois, United States of America
| | - Heather Nelson
- School of Public Health, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Lei Huang
- Center for Research Informatics, University of Chicago, Chicago, Illinois, United States of America
| | - Karin Haack
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Jack Kent
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Jason G. Umans
- MedStar Health Research Institute, Hyattsville, Maryland, United States of America
- Georgetown-Howard Universities Center for Clinical and Translational Science, Georgetown University, Washington, District of Columbia, United States of America
| | - Joseph Graziano
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
- Department of Pharmacology, Columbia University, New York City, New York, United States of America
| | - Ana Navas-Acien
- Mailman School of Public Health, Columbia University, New York City, New York, United States of America
| | - Margaret R. Karagas
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Habib Ahsan
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois, United States of America
- Comprehensive Cancer Center, University of Chicago, Chicago, Illinois, United States of America
- Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
| | - Brandon L. Pierce
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois, United States of America
- Comprehensive Cancer Center, University of Chicago, Chicago, Illinois, United States of America
- Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America
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Inherited genetic effects on arsenic metabolism: A comparison of effects on arsenic species measured in urine and in blood. Environ Epidemiol 2022; 6:e230. [PMID: 36530933 PMCID: PMC9746746 DOI: 10.1097/ee9.0000000000000230] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 09/16/2022] [Indexed: 02/05/2023] Open
Abstract
Inorganic arsenic (iAs) is a carcinogen, and chronic exposure is associated with adverse health outcomes, including cancer and cardiovascular disease. Consumed iAs can undergo two methylation reactions catalyzed by arsenic methyltransferase (AS3MT), producing monomethylated and dimethylated forms of arsenic (MMA and DMA). Methylation of iAs helps facilitate excretion of arsenic in urine, with DMA composing the majority of arsenic species excreted. Past studies have identified genetic variation in the AS3MT (10q24.32) and FTCD (21q22.3) regions associated with arsenic metabolism efficiency (AME), measured as the proportion of each species present in urine (iAs%, MMA%, and DMA%), but their association with arsenic species present in blood has not been examined. We use data from three studies nested within the Health Effects and Longitudinal Study (HEALS)-the Nutritional Influences on Arsenic Toxicity Study, the Folate and Oxidative Stress study, and the Folic Acid and Creatine Trial-to examine the association of previously identified genetic variants with arsenic species in both urine and blood of 334 individuals. We confirm that the genetic variants in AS3MT and FTCD known to effect arsenic species composition in urine (an excreted byproduct of metabolism) have similar effects on arsenic species in blood (a tissue type that directly interacts with many organs, including those prone to arsenic toxicity). This consistency we observe provides further support for the hypothesis the AME SNPs identified to date impact the efficiency of arsenic metabolism and elimination, thereby influencing internal dose of arsenic and the dose delivered to toxicity-prone organs and tissues.
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Mendelian randomization analysis of arsenic metabolism and pulmonary function within the Hispanic Community Health Study/Study of Latinos. Sci Rep 2021; 11:13470. [PMID: 34188144 PMCID: PMC8242019 DOI: 10.1038/s41598-021-92911-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 06/17/2021] [Indexed: 02/06/2023] Open
Abstract
Arsenic exposure has been linked to poor pulmonary function, and inefficient arsenic metabolizers may be at increased risk. Dietary rice has recently been identified as a possible substantial route of exposure to arsenic, and it remains unknown whether it can provide a sufficient level of exposure to affect pulmonary function in inefficient metabolizers. Within 12,609 participants of HCHS/SOL, asthma diagnoses and spirometry-based measures of pulmonary function were assessed, and rice consumption was inferred from grain intake via a food frequency questionnaire. After stratifying by smoking history, the relationship between arsenic metabolism efficiency [percentages of inorganic arsenic (%iAs), monomethylarsenate (%MMA), and dimethylarsinate (%DMA) species in urine] and the measures of pulmonary function were estimated in a two-sample Mendelian randomization approach (genotype information from an Illumina HumanOmni2.5-8v1-1 array), focusing on participants with high inferred rice consumption. Among never-smoking high inferred consumers of rice (n = 1395), inefficient metabolism was associated with past asthma diagnosis and forced vital capacity below the lower limit of normal (LLN) (OR 1.40, p = 0.0212 and OR 1.42, p = 0.0072, respectively, for each percentage-point increase in %iAs; OR 1.26, p = 0.0240 and OR 1.24, p = 0.0193 for %MMA; OR 0.87, p = 0.0209 and OR 0.87, p = 0.0123 for the marker of efficient metabolism, %DMA). Among ever-smoking high inferred consumers of rice (n = 1127), inefficient metabolism was associated with peak expiratory flow below LLN (OR 1.54, p = 0.0108/percentage-point increase in %iAs, OR 1.37, p = 0.0097 for %MMA, and OR 0.83, p = 0.0093 for %DMA). Less efficient arsenic metabolism was associated with indicators of pulmonary dysfunction among those with high inferred rice consumption, suggesting that reductions in dietary arsenic could improve respiratory health.
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