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Pyatha S, Kim H, Lee D, Kim K. Co-exposure to lead, mercury, and cadmium induces neurobehavioral impairments in mice by interfering with dopaminergic and serotonergic neurotransmission in the striatum. Front Public Health 2023; 11:1265864. [PMID: 38026429 PMCID: PMC10662100 DOI: 10.3389/fpubh.2023.1265864] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Humans are exposed to lead (Pb), mercury (Hg), and cadmium (Cd) through various routes, including drinking water, and such exposure can lead to a range of toxicological effects. However, few studies have investigated the toxic effects of exposure to mixtures of metals, particularly in relation to neurotoxicity. In this study, 7-week-old male mice were exposed to Pb, Hg, and Cd individually or in combination through their drinking water for 28 days. The mice exposed to the metal mixture exhibited significantly reduced motor coordination and impaired learning and memory abilities compared to the control group and each of the single metal exposure groups, indicating a higher level of neurotoxicity of the metal mixture. The dopamine content in the striatum was significantly lower in the metal mixture exposure group than in the single metal exposure groups and the control group. Furthermore, compared to the control group, the metal mixture exposure group showed a significantly lower expression level of tyrosine hydroxylase (TH) and significantly higher expression levels of dopamine transporter (DAT), tryptophan hydroxylase 1 (TPH1), and serotonin reuptake transporter (SERT). Notably, there were no significant differences in SERT expression between the single metal exposure groups and the control group, but SERT expression was significantly higher in the metal mixture exposure group than in the single metal and control groups. These findings suggest that the key proteins involved in the synthesis and reuptake of dopamine (TH and DAT, respectively), as well as in the synthesis and reuptake of serotonin (TPH1 and SERT, respectively), play crucial roles in the neurotoxic effects associated with exposure to metal mixtures. In conclusion, this study demonstrates that simultaneous exposure to different metals can impact key enzymes involved in dopaminergic and serotonergic neurotransmission processes, leading to disruptions in dopamine and serotonin homeostasis and consequently a range of detrimental neurobehavioral effects.
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Affiliation(s)
| | | | | | - Kisok Kim
- College of Pharmacy, Keimyung University, Daegu, Republic of Korea
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2
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Takeuchi H, Shiota Y, Yaoi K, Taki Y, Nouchi R, Yokoyama R, Kotozaki Y, Nakagawa S, Sekiguchi A, Iizuka K, Hanawa S, Araki T, Miyauchi CM, Sakaki K, Nozawa T, Ikeda S, Yokota S, Magistro D, Sassa Y, Kawashima R. Mercury levels in hair are associated with reduced neurobehavioral performance and altered brain structures in young adults. Commun Biol 2022; 5:529. [PMID: 35655003 PMCID: PMC9163068 DOI: 10.1038/s42003-022-03464-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 05/09/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractThe detrimental effects of high-level mercury exposure on the central nervous system as well as effects of low-level exposure during early development have been established. However, no previous studies have investigated the effects of mercury level on brain morphometry using advance imaging techniques in young adults. Here, utilizing hair analysis which has been advocated as a method for biological monitoring, data of regional gray matter volume (rGMV), regional white matter volume (rWMV), fractional anisotropy (FA) and mean diffusivity (MD), cognitive functions, and depression among 920 healthy young adults in Japan, we showed that greater hair mercury levels were weakly but significantly associated with diminished cognitive performance, particularly on tasks requiring rapid processing (speed measures), lower depressive tendency, lower rGMV in areas of the thalamus and hippocampus, lower rWMV in widespread areas, greater FA in bilaterally distributed white matter areas overlapping with areas of significant rWMV reductions and lower MD of the widely distributed gray and white matter areas particularly in the bilateral frontal lobe and the right basal ganglia. These results suggest that even normal mercury exposure levels in Japan are weakly associated with differences of brain structures and lower neurobehavioral performance and altered mood among young adults.
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Jonidi Jafari A, Esrafili A, Moradi Y, Mahmoudi N. Mercury level in biological samples of dentists in Iran: a systematic review and meta-analysis. JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE & ENGINEERING 2020; 18:1655-1669. [PMID: 33312669 PMCID: PMC7721756 DOI: 10.1007/s40201-020-00558-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 09/29/2020] [Indexed: 05/09/2023]
Abstract
Exposure to mercury is an important risk to dentists health. The aim of the present study was to assess the pooled mean mercury level (MML) in the urine, blood, nail, and hair of Iranian dentists (IDs) through the meta-analysis technique. Comprehensive and systematic searches were performed in main local databases including SID, Magiran, Iran medex, and ISC as well as internationally available databases including Embase, PubMed and Scopus for all the relevant studies up to 2018. In order to prevent bias in this study and identify eligible studies, various steps of the study was performed independently by two researchers. Out of 13 studies in the meta-analysis process which included 1499 IDs, the mean of the mercury level in the urine, nail, and blood was estimated to be 6.29 (95% CI: 2.61-9.97, I-square: 62.7%, P: 0.006), 3.54 (95% CI: 2.81-4.28, I-square: 0.0%, P: 0.968), 11.20 (95% CI: 2.28-20.13, I-square: 59.9%, P: 0.082), respectively. The mean mercury level (MML) in the biological samples of IDs was higher than the standard of World Health Organization (WHO). So, in accordance with Article 10 of the European Union Regulations (EUR), in the context of the Minamata Convention (MC) on Dental Amalgam (DA), in order to avoid the dangers of mercury exposure in dentists, it is necessary for Iran and other countries to approve laws and to implement a national plan to reduce mercury levels and replace the appropriate materials.
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Affiliation(s)
- Ahmad Jonidi Jafari
- Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran
- Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Esrafili
- Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran
- Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran
| | - Yousef Moradi
- Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran
| | - Norouz Mahmoudi
- Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran
- Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran
- Health Research Center, Life style Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
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4
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How Occupational Mercury Neurotoxicity Is Affected by Genetic Factors. A Systematic Review. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10217706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Occupational exposure to elemental mercury still represents a significant risk in the workplace. The sensitivity of the exposed subjects varies considerably. This study aims to summarize the literature on the role of genetic factors in occupationally exposed cohorts. A systematic search of the literature was carried out on PubMed Central (PMC), MEDLINE, and Google Scholar databases in accordance with the “Preferred Reporting Items for Systematic reviews and Meta-Analyses” (PRISMA) guidelines, from 1946 to July 2020. Ten cross-sectional studies were included in the review. All studies referred to the polymorphisms that can favour some neurotoxic effects of the metal in occupational cohorts. Some genetic variants may be associated with an increase in the occupational effects of mercury. Given the limited evidence, genetic screening of all mercury-exposed workers is not recommended. However, a personalized search for polymorphisms could be taken into consideration if exposed workers report early neurotoxic symptoms.
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5
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Vasefi M, Ghaboolian-Zare E, Abedelwahab H, Osu A. Environmental toxins and Alzheimer's disease progression. Neurochem Int 2020; 141:104852. [PMID: 33010393 DOI: 10.1016/j.neuint.2020.104852] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/05/2020] [Accepted: 09/18/2020] [Indexed: 12/29/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia, which causes progressive memory loss and cognitive decline. Effective strategies to treat or prevent remains one of the most challenging undertakings in the medical field. AD is a complex and multifactorial disease that involves several risk factors. Aging and genetic factors both play important roles in the onset of the AD, however; certain environmental factors have been reported to increase the risk of AD. Chronic exposure to toxins has been seen as an environmental factor that may increase the risk of developing a neurodegenerative disease such as AD. Exposure to metals and biotoxins produced by bacteria, molds, and viruses may contribute to the cognitive decline and pathophysiology associated with AD. Toxins may contribute to the pathology of the disease through various mechanisms such as deposition of amyloid-beta (Aβ) plaques and tangles in the brain, induction of apoptosis, inflammation, or oxidative damage. Here, we will review how toxins affect brain physiology with a focus on mechanisms by which toxins may contribute to the development and progression of AD. A better understanding of these mechanisms may help contribute towards the development of an effective strategy to slow the progression of AD.
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Affiliation(s)
- Maryam Vasefi
- Department Biology, Lamar University, Beaumont, TX, United States.
| | | | | | - Anthony Osu
- Department Biology, Lamar University, Beaumont, TX, United States
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6
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One man's swordfish story: The link between Alzheimer's disease and mercury exposure. Complement Ther Med 2020; 52:102499. [PMID: 32951747 DOI: 10.1016/j.ctim.2020.102499] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 06/29/2020] [Accepted: 06/30/2020] [Indexed: 01/17/2023] Open
Abstract
It is well-documented that when mercury levels surpass the permissible value, individuals experience a myriad of symptoms that include chronic fatigue, dizziness, and loss of appetite. Mercury is also known to be one of the most potent neurotoxins. This case study depicts a 91- year-old who presented with cognitive decline diagnosed as Alzheimer's disease. This patient was found to have severely elevated mercury levels caused by consuming high mercury containing fish. Following diet adjustment and detoxification, this patient's cognitive impairment significantly improved in proportion to the decline in methylmercury level. One year later, his cognition and functional status rapidly and unexpectedly declined. A computed tomography (CT) scan revealed multiple new lacunar subacute strokes. Thus, it is critical to address biological etiologies such as mercury toxicity in the elderly population diagnosed with Alzheimer's, but end organ damage may not be reversible.
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7
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Gredilla A, Fdez-Ortiz de Vallejuelo S, Rodriguez-Iruretagoiena A, Gomez L, Oliveira MLS, Arana G, de Diego A, Madariaga JM, Silva LFO. Evidence of mercury sequestration by carbon nanotubes and nanominerals present in agricultural soils from a coal fired power plant exhaust. JOURNAL OF HAZARDOUS MATERIALS 2019; 378:120747. [PMID: 31212088 DOI: 10.1016/j.jhazmat.2019.120747] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 05/05/2019] [Accepted: 06/06/2019] [Indexed: 06/09/2023]
Abstract
Mercury (Hg) in agricultural soils could have negative effects on the environment and the human health. The exposure to high level of Hg through different absorption pathways, such as ingestion and diet through soil-plant system could permanently damage developing foetus of animals and humans. With the aim to assess the potential environmental and health risk and to study the behaviour and fate of Hg from agricultural soils to the environment, 47 soil samples were collected around a thermoelectric power plant in the Santa Catarina (Brazil). The Hg concentration measured by inductively coupled plasma mass spectrometry (ICP-MS) ranged from 0.16 to 0.56 mg kg-1. The distribution obtained by kriging interpolation allowed the identification of the main pollution sources. To see the morphology and composition of soil samples, field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM) were used combined with energy dispersive X-ray spectroscopy (EDS), showing that the carbon nanotubes and magnetite as nanomineral contributed to Hg retention. The mentioned molecular characterization, and the low Contamination Factors (CF) values obtained, suggested that there is low risk to the food security of the agro-ecosystems area near to the CFPP in the terms of Hg inputs and contamination.
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Affiliation(s)
- Ainara Gredilla
- Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country UPV/EHU, P.C. 2018, San Sebastian, Basque Country, Spain
| | - Silvia Fdez-Ortiz de Vallejuelo
- Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, P.O. Box 644, 48080, Bilbao, Basque Country, Spain.
| | - Azibar Rodriguez-Iruretagoiena
- Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, P.O. Box 644, 48080, Bilbao, Basque Country, Spain
| | - Leandro Gomez
- Department of Civil and Environmental, Universidad de la Costa, Calle 58 #55-66, 080002, Barranquilla, Atlántico, Colombia; Faculdade Meridional IMED, Senador Pinheiro 304, 99070-220, Passo Fundo, RS, Brazil
| | - Marcos L S Oliveira
- Department of Civil and Environmental, Universidad de la Costa, Calle 58 #55-66, 080002, Barranquilla, Atlántico, Colombia; Faculdade Meridional IMED, Senador Pinheiro 304, 99070-220, Passo Fundo, RS, Brazil
| | - Gorka Arana
- Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, P.O. Box 644, 48080, Bilbao, Basque Country, Spain
| | - Alberto de Diego
- Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, P.O. Box 644, 48080, Bilbao, Basque Country, Spain
| | - Juan Manuel Madariaga
- Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, P.O. Box 644, 48080, Bilbao, Basque Country, Spain
| | - Luis F O Silva
- Department of Civil and Environmental, Universidad de la Costa, Calle 58 #55-66, 080002, Barranquilla, Atlántico, Colombia; Faculdade Meridional IMED, Senador Pinheiro 304, 99070-220, Passo Fundo, RS, Brazil.
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8
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Li X, Ding L, Song L, Gao W, Wang L, Wang J. Effects of exposure to polycyclic aromatic hydrocarbons combined with high-risk human papillomavirus infection on cervical intraepithelial neoplasia: A population study in Shanxi Province, China. Int J Cancer 2019; 146:2406-2412. [PMID: 31290154 DOI: 10.1002/ijc.32562] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 06/29/2019] [Accepted: 07/02/2019] [Indexed: 12/24/2022]
Abstract
High-risk human papillomavirus (HR-HPV) infection is a major etiological agent in the progression of cervical intraepithelial neoplasia (CIN) and cervical cancer. Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic pollutants that exist widely in the environment. We hypothesized that PAHs exposure was related to the progression of cervical cancer, and could increase the effect of HR-HPV on CIN. We investigated the effects of PAHs exposure combined with HR-HPV infection on CIN in community population in Shanxi Province, China. A total of 2,285 women were enrolled into the study. HR-HPV genotypes were detected by flow-through hybridization technology. 1-hydroxypyrene (1-OHP) was detected by high-performance liquid chromatography. The top three HR-HPV genotypes were 16, 58 and 52 in turn. With unconditional logistic regression analysis, we found that HR-HPV infection (adjusted odds ratio [aOR] = 4.08, 95% confidence interval [CI]: 3.00-5.54), HPV16 infection (aOR = 4.71, 95% CI: 3.39-6.53), HPV58 infection (aOR = 2.29, 95% CI: 1.41-3.73) and PAHs high exposure (aOR = 2.57, 95% CI: 1.82-3.62) increased the risk of CIN2/3, showing an increasing trend (p < 0.001) with the severity of cervical lesions. Compared to Q1 (<0.06 μmol/molCr) levels of 1-OHP, women with Q4 (>0.11 μmol/molCr) had a higher risk for CIN2/3 (aOR = 7.68, 95% CI: 4.83-12.22). Additionally, we observed that there was a synergic effect between high exposure to PAHs and HR-HPV infection in CIN2/3. Furthermore, the results from the generalized multifactor dimensionality reduction model showed that there were joint interactions of PAHs, HPV16, HPV58 and HPV52 on the risk of CIN2/3. Our study revealed that high exposure to PAHs could increase the risk for CIN, and it posed stronger risk when combined with HR-HPV infection.
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Affiliation(s)
- Xiaoxue Li
- Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, China
| | - Ling Ding
- Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, China
| | - Li Song
- Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, China
| | - Wen Gao
- Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, China
| | - Lu Wang
- Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, China
| | - Jintao Wang
- Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, China
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9
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Warwick D, Young M, Palmer J, Ermel RW. Mercury vapor volatilization from particulate generated from dental amalgam removal with a high-speed dental drill - a significant source of exposure. J Occup Med Toxicol 2019; 14:22. [PMID: 31346345 PMCID: PMC6637613 DOI: 10.1186/s12995-019-0240-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 06/12/2019] [Indexed: 12/20/2022] Open
Abstract
Background The ubiquitous use of dental amalgam for over 180 years has resulted in the exposure of millions of dental workers to mercury. Dental amalgam contains approximately 50% mercury. Dental workers, including dentists, dental assistants, and dental hygienists, have been shown to have increased levels of mercury and suffer more from health issues related to mercury exposure than the general public. Mercury is known to be absorbed via inhalation or through the skin. There are many routine dental procedures that require the removal of dental amalgam by using the dental high-speed drill, which we suspected generates an occupational mercury exposure that is not sufficiently recognized. Results We showed that drilling dental amalgam generates particulate that volatilizes significant amounts of mercury vapor generally for more than an hour after removal. The levels of mercury vapor created by this procedure frequently exceed the safety thresholds of several jurisdictions and agencies. Conclusions A significant, underrecognized source of localized exposure to mercury vapor was identified in this study. The vapor was created by microgram levels of particulate generated from dental amalgam removal with a high-speed dental drill, even when all feasible engineering controls were used to reduce mercury exposure. This exposure may explain why dental workers incur health effects when safety thresholds are not breached. The dispersion patterns for the particulate are not known, so the use of effective skin barriers and inhalation protection are required during amalgam removal to protect the dental worker from this form of occupational mercury exposure. Standard methodologies for occupational mercury exposure assessment appear to be inadequate when assessing mercury exposure during amalgam removal.
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Affiliation(s)
- David Warwick
- Dental Practice, Hanna Dental Clinic, 202, 2nd Ave W, Hanna, Alberta Canada
| | - Matt Young
- Dental Practice, 728 5th Ave. West, Hendersonville, NC USA
| | - Joe Palmer
- Dental Practice, Palmer Distinctive Dentistry, 134 Milestone Way, Greenville, SC USA
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10
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Bjørklund G, Hilt B, Dadar M, Lindh U, Aaseth J. Neurotoxic effects of mercury exposure in dental personnel. Basic Clin Pharmacol Toxicol 2019; 124:568-574. [PMID: 30589214 DOI: 10.1111/bcpt.13199] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 12/14/2018] [Indexed: 12/29/2022]
Abstract
Numerous studies have reported neurobehavioural effects in dental personnel occupationally exposed to chronic low levels of mercury (Hg). Hg exposure from dental work may also induce various chronic conditions such as elevation of amyloid protein expression, deterioration of microtubules and increase or inhibition of transmitter release at motor nerve terminal endings. Therefore, clinical studies of Hg toxicity in dentistry may provide new knowledge about disturbed metal homeostasis in neurodegenerative diseases such as Alzheimer's disease, multiple sclerosis and mood disorders. The purpose of this MiniReview is to evaluate the evidence of possible relevance between Hg exposure in dentistry and idiopathic disturbances in motor functions, cognitive skills and affective reactions, as well as dose-response relationships.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
| | - Bjørn Hilt
- Department of Occupational Medicine, St. Olav University Hospital, Trondheim, Norway.,Department of Public Health and Nursing, Norwegian University of Science and Technology, Trondheim, Norway
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Ulf Lindh
- Biology Education Centre, Uppsala University, Uppsala, Sweden
| | - Jan Aaseth
- Research Department, Innlandet Hospital Trust, Brumunddal, Norway.,Faculty of Health and Social Science, Inland Norway University of Applied Sciences, Elverum, Norway
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11
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Parajuli RP, Goodrich JM, Chan LHM, Ayotte P, Lemire M, Hegele RA, Basu N. Genetic polymorphisms are associated with exposure biomarkers for metals and persistent organic pollutants among Inuit from the Inuvialuit Settlement Region, Canada. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 634:569-578. [PMID: 29635199 DOI: 10.1016/j.scitotenv.2018.03.331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/12/2018] [Accepted: 03/23/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Inuit are exposed to some of the highest levels of contaminants worldwide. Studies suggest that several genes that mediate the metabolism of these contaminants are polymorphic. We hypothesize that single nucleotide polymorphisms (SNPs) in such genes may underline differences in biomarker concentrations and/or modify exposure-biomarker associations. METHODS Members from the Inuvialuit Settlement Region (Canada) were recruited. Blood concentrations of mercury (Hg), cadmium (Cd), lead (Pb), dichlorodiphenyldichloroethylene (DDE), and polychlorinated biphenyl (PCB-153) were measured. SNPs from pathways such as glutathione, metallothionein, oxidative stress, and xenobiotic transport were genotyped in 281 participants, and data from 112 SNPs were included in the analyses. Surveys were administered to obtain information on demographics, and key sources of Hg (diet) and Cd (smoking) exposure. ANOVA and linear regressions were used for data analyses. RESULTS Geometric mean concentrations of metals were 4.6μg/L for Hg, 1.3μg/L for Cd, and 32.2μg/L for Pb. Concentrations of organic pollutants were 2.0μg/L for DDE and 0.6μg/L for PCB-153. Biomarker levels for Hg, Cd, Pb, DDE, and PCB-153 differed (p<0.05) by genotype for 4, 3, 4, 3, and 3 SNPs, respectively. In multivariable analyses (for Pb, DDE, PCB-153) adjusting age, sex and body mass index (BMI), only 2 associations (one for Pb and one for DDE) remained significant. In multivariable analyses accounting for sources of Hg or Cd exposure, 24 SNPs (9 for Hg, 15 for Cd with 4 overlapping) had significant (p<0.05) main effects on biomarker levels and/or modified exposure-biomarker associations. CONCLUSION The findings suggest that polymorphisms in key environmentally responsive genes can influence biomarker levels and/or modify exposure-biomarker associations for contaminants of concern to Arctic populations. Consideration of such gene-environment results may help improve the ability to conduct exposure (and ultimately risk) assessments of country foods and Inuit health.
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Affiliation(s)
- Rajendra Prasad Parajuli
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec H9X 3V9, Canada
| | - Jaclyn M Goodrich
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | | | - Pierre Ayotte
- Axe santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Université Laval, QC, Canada; Centre de toxicologie du Québec, Institut national de santé publique du Québec, QC, Canada
| | - Melanie Lemire
- Axe santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Université Laval, QC, Canada
| | | | - Niladri Basu
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec H9X 3V9, Canada; Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA.
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12
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Sidhu MK, Thompson PJ, Wandschneider B, Foulkes A, de Tisi J, Stretton J, Perona M, Thom M, Bonelli SB, Burdett J, Williams E, Duncan JS, Matarin M. The impact of brain-derived neurotrophic factor Val66Met polymorphism on cognition and functional brain networks in patients with intractable partial epilepsy. CNS Neurosci Ther 2018; 25:223-232. [PMID: 29952080 DOI: 10.1111/cns.13003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 01/08/2023] Open
Abstract
INTRODUCTION Medial temporal lobe epilepsy (mTLE) is the most common refractory focal epilepsy in adults. Around 30%-40% of patients have prominent memory impairment and experience significant postoperative memory and language decline after surgical treatment. BDNF Val66Met polymorphism has also been associated with cognition and variability in structural and functional hippocampal indices in healthy controls and some patient groups. AIMS We examined whether BDNF Val66Met variation was associated with cognitive impairment in mTLE. METHODS In this study, we investigated the association of Val66Met polymorphism with cognitive performance (n = 276), postoperative cognitive change (n = 126) and fMRI activation patterns during memory encoding and language paradigms in 2 groups of patients with mTLE (n = 37 and 34). RESULTS mTLE patients carrying the Met allele performed more poorly on memory tasks and showed reduced medial temporal lobe activation and reduced task-related deactivations within the default mode networks in both the fMRI memory and language tasks than Val/Val patients. CONCLUSIONS Although cognitive impairment in epilepsy is the result of a complex interaction of factors, our results suggest a role of genetic factors on cognitive impairment in mTLE.
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Affiliation(s)
- Meneka K Sidhu
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.,Epilepsy Society MRI Unit, Chesham Lane, Buckinghamshire, UK
| | - Pamela J Thompson
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.,Epilepsy Society MRI Unit, Chesham Lane, Buckinghamshire, UK
| | - Britta Wandschneider
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Alexandra Foulkes
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Jane de Tisi
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Jason Stretton
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.,Epilepsy Society MRI Unit, Chesham Lane, Buckinghamshire, UK
| | - Marina Perona
- Department of Radiobiology (CAC), National Atomic Energy Commission (CNEA), National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina.,Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Maria Thom
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | | | - Jane Burdett
- Epilepsy Society MRI Unit, Chesham Lane, Buckinghamshire, UK
| | - Elaine Williams
- Epilepsy Society MRI Unit, Chesham Lane, Buckinghamshire, UK
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.,Epilepsy Society MRI Unit, Chesham Lane, Buckinghamshire, UK
| | - Mar Matarin
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.,Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
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13
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Geary DC. Evolution of Human Sex-Specific Cognitive Vulnerabilities. QUARTERLY REVIEW OF BIOLOGY 2017. [DOI: 10.1086/694934] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Bailey JM, Colón-Rodríguez A, Atchison WD. Evaluating a Gene-Environment Interaction in Amyotrophic Lateral Sclerosis: Methylmercury Exposure and Mutated SOD1. Curr Environ Health Rep 2017; 4:200-207. [PMID: 28397096 DOI: 10.1007/s40572-017-0144-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Gene-environment (GxE) interactions likely contribute to numerous diseases, but are often difficult to model in the laboratory. Such interactions have been widely hypothesized for amyotrophic lateral sclerosis (ALS); recent controlled laboratory studies are discussed here and hypotheses related to possible mechanisms of action are offered. Using methylmercury exposure and mutated SOD1 to model the impacts of such an interaction, we interpret evidence about their respective mechanisms of toxicity to interrogate the possibility of additive (or synergistic) effects when combined. RECENT FINDINGS Recent work has converged on mechanisms of calcium-mediated glutamate excitotoxicity as a likely contributor in one model of a gene-environment interaction affecting the onset and progression of ALS-like phenotype. The current experimental literature on mechanisms of metal-induced neuronal injury and their relevant interactions with genetic contributions in ALS is sparse, but we describe those studies here and offer several integrative hypotheses about the likely mechanisms involved.
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Affiliation(s)
- Jordan M Bailey
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA.,Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA
| | - Alexandra Colón-Rodríguez
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA.,Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA.,Comparative Medicine and Integrative Biology Program, Michigan State University, East Lansing, MI, 48824-1317, USA
| | - William D Atchison
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA. .,Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA. .,Comparative Medicine and Integrative Biology Program, Michigan State University, East Lansing, MI, 48824-1317, USA. .,, Life Science Building, 1355 Bogue St. Room B331A, East Lansing, MI, 48824-1317, USA.
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15
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Carroll CR, Noonan C, Garroutte EM, Navas-Acien A, Verney SP, Buchwald D. Low-level inorganic arsenic exposure and neuropsychological functioning in American Indian elders. ENVIRONMENTAL RESEARCH 2017; 156:74-79. [PMID: 28334644 PMCID: PMC5485900 DOI: 10.1016/j.envres.2017.03.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 03/11/2017] [Accepted: 03/13/2017] [Indexed: 05/20/2023]
Abstract
BACKGROUND Inorganic arsenic at high and prolonged doses is highly neurotoxic. Few studies have evaluated whether long-term, low-level arsenic exposure is associated with neuropsychological functioning in adults. OBJECTIVES To investigate the association between long-term, low-level inorganic arsenic exposure and neuropsychological functioning among American Indians aged 64-95. METHODS We assessed 928 participants in the Strong Heart Study by using data on arsenic species in urine samples collected at baseline (1989-1991) and results of standardized tests of global cognition, executive functioning, verbal learning and memory, fine motor functioning, and speed of mental processing administered during comprehensive follow-up evaluations in 2009-2013. We calculated the difference in neuropsychological functioning for a 10% increase in urinary arsenic with adjustment for sex, age, education, and study site. RESULTS The sum of inorganic and methylated arsenic species (∑As) in urine was associated with limited fine motor functioning and processing speed. A 10% increase in ∑As was associated with a .10 (95% CI -.20, -.01) decrease on the Finger Tapping Test for the dominant hand and a .13 decrease (95% CI -.21, -.04) for the non-dominant hand. Similarly, a 10% increase in ∑As was associated with a .15 (95% CI -.29, .00) decrease on the Wechsler Adult Intelligence Scale-Fourth Edition Coding Subtest. ∑As was not associated with other neuropsychological functions. CONCLUSIONS Findings indicate an adverse association between increased urinary arsenic fine motor functioning and processing speed, but not with other neuropsychological functioning, among elderly American Indians.
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Affiliation(s)
- Clint R Carroll
- Department of Ethnic Studies, University of Colorado, Boulder, CO, USA.
| | - Carolyn Noonan
- Initiative for Research and Education to Advance Community Health (IREACH), Washington State University, Spokane, WA, USA
| | - Eva M Garroutte
- Department of Sociology, Boston College, Chestnut Hill, MA, USA
| | - Ana Navas-Acien
- Departments of Environmental Health Sciences and Epidemiology, Columbia University, New York, NY, USA
| | - Steven P Verney
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA
| | - Dedra Buchwald
- Initiative for Research and Education to Advance Community Health (IREACH), Washington State University, Spokane, WA, USA
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Khan H, Singh RD, Tiwari R, Gangopadhyay S, Roy SK, Singh D, Srivastava V. Mercury exposure induces cytoskeleton disruption and loss of renal function through epigenetic modulation of MMP9 expression. Toxicology 2017; 386:28-39. [DOI: 10.1016/j.tox.2017.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 05/09/2017] [Accepted: 05/15/2017] [Indexed: 11/30/2022]
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17
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Milioni ALV, Nagy BV, Moura ALA, Zachi EC, Barboni MT, Ventura DF. Neurotoxic impact of mercury on the central nervous system evaluated by neuropsychological tests and on the autonomic nervous system evaluated by dynamic pupillometry. Neurotoxicology 2017; 59:263-269. [DOI: 10.1016/j.neuro.2016.04.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 04/09/2016] [Accepted: 04/11/2016] [Indexed: 11/25/2022]
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Genetic Aspects of Susceptibility to Mercury Toxicity: An Overview. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14010093. [PMID: 28106810 PMCID: PMC5295343 DOI: 10.3390/ijerph14010093] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/16/2016] [Accepted: 01/12/2017] [Indexed: 12/12/2022]
Abstract
Human exposure to mercury is still a major public health concern. In this context, children have a higher susceptibility to adverse neurological mercury effects, compared to adults with similar exposures. Moreover, there exists a marked variability of personal response to detrimental mercury action, in particular among population groups with significant mercury exposure. New scientific evidence on genetic backgrounds has raised the issue of whether candidate susceptibility genes can make certain individuals more or less vulnerable to mercury toxicity. In this review, the aim is to evaluate a new genetic dimension and its involvement in mercury risk assessment, focusing on the important role played by relevant polymorphisms, located in attractive gene targets for mercury toxicity. Existing original articles on epidemiologic research which report a direct link between the genetic basis of personal vulnerability and different mercury repercussions on human health will be reviewed. Based on this evidence, a careful evaluation of the significant markers of susceptibility will be suggested, in order to obtain a powerful positive “feedback” to improve the quality of life. Large consortia of studies with clear phenotypic assessments will help clarify the “window of susceptibility” in the human health risks due to mercury exposure.
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Bjørklund G, Bengtsson U, Chirumbolo S, Kern JK. Concerns about environmental mercury toxicity: do we forget something else? ENVIRONMENTAL RESEARCH 2017; 152:514-516. [PMID: 27616662 DOI: 10.1016/j.envres.2016.08.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 08/20/2016] [Accepted: 08/24/2016] [Indexed: 05/24/2023]
Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine (CONEM), Toften 24, 8610 Mo i Rana, Norway.
| | - Ulf Bengtsson
- Ret. Department of Management and Engineering, Linköping University, Linköping, Sweden
| | - Salvatore Chirumbolo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | - Janet K Kern
- Institute of Chronic Illnesses, Inc, and CoMeD, Silver Spring, MD, USA; CONEM US Autism Research Group, Allen, TX, USA
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20
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Ha E, Basu N, Bose-O'Reilly S, Dórea JG, McSorley E, Sakamoto M, Chan HM. Current progress on understanding the impact of mercury on human health. ENVIRONMENTAL RESEARCH 2017; 152:419-433. [PMID: 27444821 DOI: 10.1016/j.envres.2016.06.042] [Citation(s) in RCA: 205] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 06/22/2016] [Accepted: 06/25/2016] [Indexed: 05/18/2023]
Abstract
Mercury pollution and its impacts on human health is of global concern. The authors of this paper were members of the Plenary Panel on Human Health in the 12th International Conference on Mercury as a Global Pollutant held in Korea in June 2015. The Panel was asked by the conference organizers to address two questions: what is the current understanding of the impacts of mercury exposure on human health and what information is needed to evaluate the effectiveness of the Minamata Convention in lowering exposure and preventing adverse effects. The authors conducted a critical review of the literature published since January 2012 and discussed the current state-of-knowledge in the following areas: environmental exposure and/or risk assessment; kinetics and biomonitoring; effects on children development; effects on adult general populations; effects on artisanal and small-scale gold miners (ASGM); effects on dental workers; risk of ethylmercury in thimerosal-containing vaccines; interactions with nutrients; genetic determinants and; risk communication and management. Knowledge gaps in each area were identified and recommendations for future research were made. The Panel concluded that more knowledge synthesis efforts are needed to translate the research results into management tools for health professionals and policy makers.
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Affiliation(s)
- Eunhee Ha
- Ewha Womans University, College of Medicine, Department of Preventive Medicine, South Korea
| | - Niladri Basu
- Faculty of Agricultural and Environmental Sciences, McGill University, Canada
| | - Stephan Bose-O'Reilly
- University Hospital Munich, Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, WHO Collaborating Centre for Occupational Health, Germany; University for Health Sciences, Medical Informatics and Technology (UMIT), Department of Public Health, Health Services Research and Health Technology Assessment, Austria
| | - José G Dórea
- Department of Nutrition, University of Brasília, Brasília, Brazil
| | - Emeir McSorley
- Northern Ireland Centre for Food and Health, Ulster University, United Kingdom
| | - Mineshi Sakamoto
- Department of Epidemiology, National Institute for Minamata Disease, Japan
| | - Hing Man Chan
- Department of Biology, University of Ottawa, Canada.
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Chen W, Chen C, Xia M, Wu K, Chen C, He Q, Xue G, Wang W, He Y, Dong Q. Interaction Effects of BDNF and COMT Genes on Resting-State Brain Activity and Working Memory. Front Hum Neurosci 2016; 10:540. [PMID: 27853425 PMCID: PMC5091010 DOI: 10.3389/fnhum.2016.00540] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 10/11/2016] [Indexed: 12/18/2022] Open
Abstract
Catechol-O-methyltransferase (COMT) and brain-derived neurotrophic factor (BDNF) genes have been found to interactively influence working memory (WM) as well as brain activation during WM tasks. However, whether the two genes have interactive effects on resting-state activities of the brain and whether these spontaneous activations correlate with WM are still unknown. This study included behavioral data from WM tasks and genetic data (COMT rs4680 and BDNF Val66Met) from 417 healthy Chinese adults and resting-state fMRI data from 298 of them. Significant interactive effects of BDNF and COMT were found for WM performance as well as for resting-state regional homogeneity (ReHo) in WM-related brain areas, including the left medial frontal gyrus (lMeFG), left superior frontal gyrus (lSFG), right superior and medial frontal gyrus (rSMFG), right medial orbitofrontal gyrus (rMOFG), right middle frontal gyrus (rMFG), precuneus, bilateral superior temporal gyrus, left superior occipital gyrus, right middle occipital gyrus, and right inferior parietal lobule. Simple effects analyses showed that compared to other genotypes, subjects with COMT-VV/BDNF-VV had higher WM and lower ReHo in all five frontal brain areas. The results supported the hypothesis that COMT and BDNF polymorphisms influence WM performance and spontaneous brain activity (i.e., ReHo).
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Affiliation(s)
- Wen Chen
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijing, China
- Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal UniversityBeijing, China
| | - Chunhui Chen
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijing, China
- Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal UniversityBeijing, China
| | - Mingrui Xia
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijing, China
- Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal UniversityBeijing, China
| | - Karen Wu
- Department of Psychology and Social Behavior, University of CaliforniaIrvine, CA, USA
| | - Chuansheng Chen
- Department of Psychology and Social Behavior, University of CaliforniaIrvine, CA, USA
| | - Qinghua He
- Faculty of Psychology, Southwest UniversityChongqing, China
| | - Gui Xue
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijing, China
- Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal UniversityBeijing, China
| | - Wenjing Wang
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijing, China
- Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal UniversityBeijing, China
| | - Yong He
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijing, China
- Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal UniversityBeijing, China
| | - Qi Dong
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijing, China
- Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal UniversityBeijing, China
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Rizzetti DA, Fernandez F, Moreno S, Uranga Ocio JA, Peçanha FM, Vera G, Vassallo DV, Castro MM, Wiggers GA. Egg white hydrolysate promotes neuroprotection for neuropathic disorders induced by chronic exposure to low concentrations of mercury. Brain Res 2016; 1646:482-489. [DOI: 10.1016/j.brainres.2016.06.037] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/22/2016] [Accepted: 06/24/2016] [Indexed: 01/01/2023]
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Parajuli RP, Goodrich JM, Chou HN, Gruninger SE, Dolinoy DC, Franzblau A, Basu N. Genetic polymorphisms are associated with hair, blood, and urine mercury levels in the American Dental Association (ADA) study participants. ENVIRONMENTAL RESEARCH 2016; 149:247-258. [PMID: 26673400 PMCID: PMC4897752 DOI: 10.1016/j.envres.2015.11.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/25/2015] [Accepted: 11/26/2015] [Indexed: 05/21/2023]
Abstract
BACKGROUND/AIMS Mercury (Hg) is a potent toxicant of concern to the general public. Recent studies suggest that several genes that mediate Hg metabolism are polymorphic. We hypothesize that single nucleotide polymorphisms (SNPs) in such genes may underline inter-individual differences in exposure biomarker concentrations. METHODS Dental professionals were recruited during the American Dental Association (ADA) 2012 Annual Meeting. Samples of hair, blood, and urine were collected for quantifying Hg levels and genotyping (88 SNPs in classes relevant to Hg toxicokinetics including glutathione metabolism, selenoproteins, metallothioneins, and xenobiotic transporters). Questionnaires were administrated to obtain information on demographics and sources of Hg exposure (e.g., fish consumption and use of dental amalgam). Here, we report results for 380 participants with complete genotype and Hg biomarker datasets. ANOVA and linear regressions were used for statistical analysis. RESULTS Mean (geometric) Hg levels in hair (hHg), blood (bHg), urine (uHg), and the average estimated Hg intake from fish were 0.62µg/g, 3.75µg/L, 1.32µg/L, and 0.12µg/kg body weight/day, respectively. Out of 88 SNPs successfully genotyped, Hg biomarker levels differed by genotype for 25 SNPs, one of which remained significant following Bonferroni correction in ANOVA. When the associations between sources of Hg exposure and SNPs were analyzed with respect to Hg biomarker concentrations, 38 SNPs had significant main effects and/or gene-Hg exposure source interactions. Twenty-five, 23, and four SNPs showed significant main effects and/or interactions for hHg, bHg, and uHg levels, respectively (p<0.05), and six SNPs (in GCLC, MT1M, MT4, ATP7B, and BDNF) remained significant following Bonferroni correction. CONCLUSION The findings suggest that polymorphisms in environmentally-responsive genes can influence Hg biomarker levels. Hence, consideration of such gene-environment factors may improve the ability to assess the health risks of Hg more precisely.
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Affiliation(s)
- Rajendra Prasad Parajuli
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec, Canada.
| | - Jaclyn M Goodrich
- Department of Environmental Health Sciences, Unisiversity of Michigan School of Public Health, Ann Arbor, MI, USA.
| | | | | | - Dana C Dolinoy
- Department of Environmental Health Sciences, Unisiversity of Michigan School of Public Health, Ann Arbor, MI, USA; Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA.
| | - Alfred Franzblau
- Department of Environmental Health Sciences, Unisiversity of Michigan School of Public Health, Ann Arbor, MI, USA.
| | - Niladri Basu
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec, Canada; Department of Environmental Health Sciences, Unisiversity of Michigan School of Public Health, Ann Arbor, MI, USA.
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Rodríguez LHS, Rodríguez-Villamizar LA, Flórez-Vargas O, Fiallo YV, Ordoñez Á, Gutiérrez MDC. No effect of mercury exposure on kidney function during ongoing artisanal gold mining activities in Colombia. Toxicol Ind Health 2016; 33:67-78. [PMID: 27449026 DOI: 10.1177/0748233716659031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This cross-sectional study examined whether people who are exposed to mercury (Hg) vapours in ongoing artisanal gold mining activities have alteration in kidney function monitoring parameters. The study enrolled 164 miners and 127 participant controls. The Hg concentrations for miners and control participants were measured in blood (B-Hg; median 7.0 vs. 2.5 µg/L), urine (U-Hg; median 3.9 vs. 1.5 µg/g creatinine) and hair (H-Hg; median 0.8 vs. 0.4 µg/g hair). The biomarkers of renal function were creatinine, albumin and excretion of β-2 microglobulin. Glomerular filtration rate (eGFR) was calculated using the chronic kidney disease epidemiology collaboration equation. Significant statistical differences were found in Hg concentrations and eGFR levels between the two study groups ( p < 0.01) but not with the other biomarkers of renal function. A multiple regression model was applied to explore the relationship of eGFR levels and Hg concentrations. However, no association was found between the prevalence of reduced eGFR (<71.96 mL/min/1.73 m2) and the B-Hg or U-Hg levels after adjustment for covariates. Nevertheless, it was observed that having B-Hg levels above 10 µg Hg/L decreased the eGFR by 1.7 mL/min/1.73 m2 (confidence interval 95% -5.1 to 1.7) compared to having levels below 2.0 µg Hg/L. Our results found no support for kidney damage associated with Hg vapour exposure in ongoing artisanal gold mining, whose population has a level of Hg exposure from low to moderate (B-Hg from 3.4 to 11.0 µg/L and U-Hg from 1.3 to 9.6 µg/g creatinine).
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Affiliation(s)
- Luz Helena Sánchez Rodríguez
- 1 Laboratory of Environmental Toxicology and Toxicogenomics, Group of Immunology and Molecular Epidemiology, Faculty of Health, Universidad Industrial de Santander, Bucaramanga, Colombia.,2 School of Microbiology, Universidad Industrial de Santander, Bucaramanga, Colombia
| | | | - Oscar Flórez-Vargas
- 1 Laboratory of Environmental Toxicology and Toxicogenomics, Group of Immunology and Molecular Epidemiology, Faculty of Health, Universidad Industrial de Santander, Bucaramanga, Colombia
| | - Yolanda Vargas Fiallo
- 4 Laboratory of Industrial Consulting, School of Chemistry, Universidad Industrial de Santander, Bucaramanga, Colombia
| | - Álvaro Ordoñez
- 5 Renal Clinic, Hospital Universitario de Santander, Bucaramanga, Colombia
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Vähäsarja N, Montgomery S, Sandborgh-Englund G, Ekbom A, Ekstrand J, Näsman P, Naimi-Akbar A. Neurological disease or intellectual disability among sons of female Swedish dental personnel. J Perinat Med 2016; 44:453-60. [PMID: 25741733 DOI: 10.1515/jpm-2014-0294] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 01/23/2015] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Prenatal exposure to elemental mercury may be a potential hazard for the offspring of female dental personnel working with dental amalgam. The aim of this study was to investigate whether potential in utero exposure to mercury might have affected the development of nervous system of the sons of Swedish female dental personnel leading to an increased risk of neurological disease or intellectual disability. MATERIAL AND METHODS We used national Swedish registers to investigate risks for diseases potentially related to adverse effects on neurodevelopment. Sons of female dentists (n=1690) and dental nurses (n=10,420) were compared with cohorts consisting of sons of other female healthcare personnel. Due to changes in mercury exposure in dentistry during the study period, analyses were stratified by decade of birth. Hazard ratios (HRs) were calculated using Cox proportional hazard models. RESULTS We found no elevated risk for neurological disease, epilepsy or intellectual disability among the sons of dental personnel during any of the decades studied. HRs for neurological disease among the dental nurse cohort were even below 1.00 during the 1970s and 1980s. A low number of events resulted in uncertainty regarding results in the dentist cohort. CONCLUSIONS We did not find any support for the hypothesis that mercury exposure in Swedish dentistry during the 1960s, 1970s or 1980s had any effect on the incidence of neurological disease or intellectual disability among the sons of female dental personnel. Our results imply that current use of dental amalgam should not represent an elevated risk for neurological disease or intellectual disability among the offspring of dental personnel.
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Goodrich JM, Chou HN, Gruninger SE, Franzblau A, Basu N. Exposures of dental professionals to elemental mercury and methylmercury. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2016; 26:78-85. [PMID: 26329138 PMCID: PMC4689636 DOI: 10.1038/jes.2015.52] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 07/28/2015] [Indexed: 05/03/2023]
Abstract
Mercury (Hg) exposure, a worldwide public health concern, predominantly takes two forms--methylmercury from fish consumption and elemental Hg from dental amalgam restorations. We recruited 630 dental professionals from an American Dental Association meeting to assess Hg body burden and primary sources of exposure in a dually exposed population. Participants described occupational practices and fish consumption patterns via questionnaire. Hg levels in biomarkers of elemental Hg (urine) and methylmercury (hair and blood) were measured with a Direct Mercury Analyzer-80 and were higher than the general US population. Geometric means (95% CI) were 1.28 (1.19-1.37) μg/l in urine, 0.60 (0.54-0.67) μg/g in hair and 3.67 (3.38-3.98) μg/l in blood. In multivariable linear regression, personal amalgams predicted urine Hg levels along with total years in dentistry, amalgams handled, working hours and sex. Fish consumption patterns predicted hair and blood Hg levels, which were higher among Asians compared with Caucasians. Five species contributed the majority of the estimated Hg intake from fish--swordfish, fresh tuna, white canned tuna, whitefish and king mackerel. When studying populations with occupational exposure to Hg, it is important to assess environmental exposures to both elemental Hg and methylmercury as these constitute a large proportion of total exposure.
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Affiliation(s)
- Jaclyn M Goodrich
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | | | | | - Alfred Franzblau
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Niladri Basu
- Department of Agriculture and Environmental Sciences, McGill University, Montreal, Quebec, Canada
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Llop S, Ballester F, Broberg K. Effect of Gene-Mercury Interactions on Mercury Toxicokinetics and Neurotoxicity. Curr Environ Health Rep 2015; 2:179-94. [DOI: 10.1007/s40572-015-0047-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Vacchi-Suzzi C, Karimi R, Kruse D, Silbernagel SM, Levine KE, Rohlman DS, Meliker JR. Low-level mercury, omega-3 index and neurobehavioral outcomes in an adult US coastal population. Eur J Nutr 2015; 55:699-711. [PMID: 25832490 DOI: 10.1007/s00394-015-0890-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/22/2015] [Indexed: 12/18/2022]
Abstract
BACKGROUND Neurodevelopmental effects of omega-3 fatty acids and mercury from fish consumption have been characterized in children. In contrast, neurobehavioral outcomes associated with fish are not well studied in adults. OBJECTIVE This study of avid seafood consumers on Long Island (NY, USA) sought to define associations between mercury, seafood consumption, omega-3 fatty acids and neurobehavioral outcomes. METHODS A computer-based test system was used to assess neurobehavioral function. Blood total Hg (Hg) and omega-3 index were measured in 199 adult avid seafood eaters, who also completed the neurobehavioral assessment and an extensive food and fish frequency and demographic questionnaire. RESULTS For most of the outcomes considered, neither Hg nor omega-3 index was associated with neurobehavioral outcomes after adjustment for key confounding variables. Fish consumption, however, was associated with decreased odds of both self-reported fatigue (OR 0.85; 95 % CI 0.72, 1.01) and a constellation of neurologic symptoms (OR 0.79; 95 % CI 0.66, 0.96). CONCLUSIONS Results from our study provide little evidence that omega-3 fatty acids or Hg is associated with cognitive function in adult avid seafood consumers. Larger studies are needed to confirm our finding of associations between fish consumption and decreased self-reported fatigue and neurologic impairment.
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Affiliation(s)
- Caterina Vacchi-Suzzi
- Program in Public Health, Department of Preventive Medicine, Stony Brook University, Stony Brook, NY, 11794, USA.
| | - Roxanne Karimi
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Danielle Kruse
- School of Medicine, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Susan M Silbernagel
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Keith E Levine
- Trace Inorganics Department, Technologies for Industry and the Environment, RTI International, Research Triangle Park, NC, 27709, USA
| | - Diane S Rohlman
- Occupational and Environmental Health, University of Iowa, Iowa City, IA, 52242, USA
- Oregon Institute for Occupational Health Sciences, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Jaymie R Meliker
- Program in Public Health, Department of Preventive Medicine, Stony Brook University, Stony Brook, NY, 11794, USA
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Delgado-Alvarez CG, Ruelas-Inzunza J, Osuna-López JI, Voltolina D, Frías-Espericueta MG. Mercury content and their risk assessment in farmed shrimp Litopenaeus vannamei from NW Mexico. CHEMOSPHERE 2015; 119:1015-1020. [PMID: 25303662 DOI: 10.1016/j.chemosphere.2014.08.079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 08/19/2014] [Accepted: 08/31/2014] [Indexed: 06/04/2023]
Abstract
The main objective of this study was to evaluate the total mercury content in hepatopancreas and edible muscle of the whiteleg shrimp Litopenaeus vannamei cultured along the NW coast of Mexico, and to evaluate the potential human health risk due to their consumption. Samples were obtained between May and June 2010 in 26 shrimp farms from the three most important shrimp-producing states of NW Mexico, and total Hg was analyzed after reduction with SnCl2 in a mercury analyzer. The ranges of Hg concentrations of the hepatopancreas were 0.101±0.03-0.184±0.13 μg g(-1) in Sonora, 0.077±0.055-0.813±0.363 μg g(-1) in Sinaloa and 0.139±0.037-0.791±0.33 μg g(-1) in Nayarit. In the muscle, values were from 0.078±0.02 to 0.539±0.09 μg g(-1) in Sonora, 0.154±0.03-0.861±0.423 μg g(-1) in Sinaloa and 0.121±0.041-1.48±0.44 μg g(-1) in Nayarit. Considering the concentrations of Hg in the muscle and the national consumption rate, shrimp farmed in NW Mexico does not represent a risk for human health (HQ<1).
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Affiliation(s)
- C G Delgado-Alvarez
- Aquatic Resources Postgraduate Program, Faculty of Marine Sciences, Autonomous University of Sinaloa, Mazatlán, Sinaloa 82000, Mexico
| | - J Ruelas-Inzunza
- Technological Institute of Mazatlán, Mazatlán, Sinaloa 82000, Mexico
| | - J I Osuna-López
- Faculty of Marine Sciences, Autonomous University of Sinaloa, Paseo Claussen s/n, Mazatlán, Sinaloa 82000, Mexico
| | - D Voltolina
- Center of Biological Studies of the NW, UAS-CIBNOR Environmental Studies Laboratory, Mazatlán, Sinaloa 82000, Mexico
| | - M G Frías-Espericueta
- Faculty of Marine Sciences, Autonomous University of Sinaloa, Paseo Claussen s/n, Mazatlán, Sinaloa 82000, Mexico.
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Zwicker JD, Dutton DJ, Emery JCH. Longitudinal analysis of the association between removal of dental amalgam, urine mercury and 14 self-reported health symptoms. Environ Health 2014; 13:95. [PMID: 25404430 PMCID: PMC4273453 DOI: 10.1186/1476-069x-13-95] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 11/03/2014] [Indexed: 05/09/2023]
Abstract
BACKGROUND Mercury vapor poses a known health risk with no clearly established safe level of exposure. Consequently there is debate over whether the level of prolonged exposure to mercury vapor from dental amalgam fillings, combining approximately 50% mercury with other metals, is sufficiently high to represent a risk to health. The objective of our study is to determine if mercury exposure from amalgam fillings is associated with risk of adverse health effects. METHODS In a large longitudinal non-blind sample of participants from a preventative health program in Calgary, Canada we compared number of amalgam fillings, urine mercury measures and changes in 14 self-reported health symptoms, proposed to be mercury dependent sub-clinical measures of mental and physical health. The likelihood of change over one year in a sample of persons who had their fillings removed was compared to a sample of persons who had not had their fillings removed. We use non-parametric statistical tests to determine if differences in urine mercury were statistically significant between sample groups. Logistic regression models were used to estimate the likelihood of observing symptom improvement or worsening in the sample groups. RESULTS At baseline, individuals with dental amalgam fillings have double the measured urine mercury compared to a control group of persons who have never had amalgam fillings. Removal of amalgam fillings decreases measured urine mercury to levels in persons without amalgam fillings. Although urine mercury levels in our sample are considered by Health Canada to be too low to pose health risks, removal of amalgam fillings reduced the likelihood of self-reported symptom deterioration and increased the likelihood of symptom improvement in comparison to people who retained their amalgam fillings. CONCLUSIONS Our findings suggest that mercury exposure from amalgam fillings adversely impact health and therefore are a health risk. The use of safer alternative materials for dental fillings should be encouraged to avoid the increased risk of health deterioration associated with unnecessary exposure to mercury.
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Affiliation(s)
- Jennifer D Zwicker
- />School of Public Policy, University of Calgary, Calgary, AB T2P 1H9 Canada
| | - Daniel J Dutton
- />School of Public Policy, University of Calgary, Calgary, AB T2P 1H9 Canada
| | - John Charles Herbert Emery
- />School of Public Policy, University of Calgary, Calgary, AB T2P 1H9 Canada
- />Department of Economics, University of Calgary, Social Sciences Building, Room 554, 2500 University Dr. NW, Calgary, AB T2N 1 N4 Canada
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Hu H, Scheidell J, Xu X, Coatsworth AM, Khan MR. Associations between blood lead level and substance use and sexually transmitted infection risk among adults in the United States. ENVIRONMENTAL RESEARCH 2014; 135:21-30. [PMID: 25261860 DOI: 10.1016/j.envres.2014.05.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 05/08/2014] [Accepted: 05/15/2014] [Indexed: 05/03/2023]
Abstract
The effects of low-level lead exposure on neuropsychological status in the United States (US) general adult population have been reported, and the relationship between neuropsychiatric dysfunction and health risk behaviors including substance use and sexual risk taking is well established. However, the potential influence of lead exposure on risk-taking behavior has received little attention. Using the National Health and Nutrition Examination Survey (NHANES) 2005-2010, we estimated multivariable logistic regression models to measure odds ratios (ORs) and 95% confidence intervals (CIs) for the cross-sectional associations between blood lead level and risk behaviors including binge drinking, drug use, and indicator of sexually transmitted infection (STI) risk. STI indicators included past 12 month sexual risk behaviors (age mixing with partners who were at least five years younger or older and multiple partnerships), self-reported STI, and biologically-confirmed herpes simplex virus type 2 (HSV-2) infection. Dose-response like relationships were observed between blood lead and substance use, age mixing with younger and older partners, self-reported STI, and HSV-2. In addition, participants with lead levels in highest quartile versus those with levels in the lowest quartile had over three times the odds of binge drinking and over twice the odds of injection drug or cocaine use in the past 12 months, while being in one of the top two quartiles was significantly associated with 30-70% increased odds of multiple partnerships, sex with older partners, and self-reported and biologically confirmed STI. Results from this study suggested that lead exposure may contribute to substance use, sexual risk-taking, and STI. However, given limitations inherent in the cross-sectional nature of the study, additional studies that use longitudinal data and measure detailed temporal information are warranted.
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Affiliation(s)
- Hui Hu
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, United States
| | - Joy Scheidell
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, United States
| | - Xiaohui Xu
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, United States
| | - Ashley M Coatsworth
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, United States
| | - Maria R Khan
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, United States.
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Naimi-Akbar A, Sandborgh-Englund G, Ekbom A, Ekstrand J, Näsman P, Montgomery S. Mortality among sons of female dental personnel--a national cohort study. J Perinat Med 2014; 42:655-61. [PMID: 24633748 DOI: 10.1515/jpm-2013-0270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 01/30/2014] [Indexed: 11/15/2022]
Abstract
AIMS Dental personnel are exposed to mercury when using dental amalgam. This exposure constitutes a potential hazard to offspring of women working in dentistry. The present study examined increased mortality risk in offspring of mothers working in dentistry. METHODS Mortality was compared between sons of dental personnel and sons of nondental health-care personnel. Hazard ratios were calculated for three decades (1960s-1980s), when the magnitude of mercury exposure in dentistry was likely to have varied. RESULTS During the 1960s, there was a statistically significant increase in the risk of neonatal mortality for sons of dental nurses when compared with sons of assistant nurses: hazard ratio (HR) 1.82 (95% confidence interval, CI: 1.04-3.22). There was no increased risk in the subsequent decades, but a trend test demonstrated a consistent decrease in the risk over the three decades: HR for trend 0.63 (95% CI: 0.44-0.90). The raised mortality risk was limited to neonatal mortality. The comparison between dentists and physicians had insufficient statistical power. CONCLUSIONS There is no increased mortality risk among sons of female dentists after the 1960s. Although the results should be interpreted with caution, they suggest a modestly raised risk of neonatal mortality, during the 1960s, when exposure to mercury was thought to be highest.
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Woods JS, Heyer NJ, Russo JE, Martin MD, Farin FM. Genetic polymorphisms affecting susceptibility to mercury neurotoxicity in children: summary findings from the Casa Pia Children's Amalgam clinical trial. Neurotoxicology 2014; 44:288-302. [PMID: 25109824 DOI: 10.1016/j.neuro.2014.07.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 07/29/2014] [Accepted: 07/30/2014] [Indexed: 12/15/2022]
Abstract
Mercury (Hg) is neurotoxic, and children may be particularly susceptible to this effect. A current major challenge is identification of children who may be uniquely susceptible to Hg toxicity because of genetic predisposition. We examined the possibility that common genetic variants that are known to affect neurologic functions or Hg handling in adults would modify the adverse neurobehavioral effects of Hg exposure in children. Three hundred thirty subjects who participated as children in the recently completed Casa Pia Clinical Trial of Dental Amalgams in Children were genotyped for 27 variants of 13 genes that are reported to affect neurologic functions and/or Hg disposition in adults. Urinary Hg concentrations, reflecting Hg exposure from any source, served as the Hg exposure index. Regression modeling strategies were employed to evaluate potential associations between allelic status for individual genes or combinations of genes, Hg exposure, and neurobehavioral test outcomes assessed at baseline and for 7 subsequent years during the clinical trial. Among boys, significant modification of Hg effects on neurobehavioral outcomes over a broad range of neurologic domains was observed with variant genotypes for 4 of 13 genes evaluated. Modification of Hg effects on a more limited number of neurobehavioral outcomes was also observed for variants of another 8 genes. Cluster analyses suggested some genes interacting in common processes to affect Hg neurotoxicity. In contrast, significant modification of Hg effects on neurobehavioral functions among girls with the same genotypes was substantially more limited. These observations suggest increased susceptibility to the adverse neurobehavioral effects of Hg among children, particularly boys, with genetic variants that are relatively common to the general human population. These findings advance public health goals to identify factors underlying susceptibility to Hg toxicity and may contribute to strategies for preventing adverse health risks associated with Hg exposure.
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Affiliation(s)
- James S Woods
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA.
| | - Nicholas J Heyer
- Battelle Centers for Public Health Research and Evaluation, Seattle, WA, USA
| | - Joan E Russo
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - Michael D Martin
- Departments of Oral Medicine and Epidemiology, University of Washington, Seattle, WA, USA
| | - Federico M Farin
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
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Basu N, Goodrich JM, Head J. Ecogenetics of mercury: from genetic polymorphisms and epigenetics to risk assessment and decision-making. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2014; 33:1248-58. [PMID: 24038486 DOI: 10.1002/etc.2375] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 05/10/2013] [Accepted: 08/08/2013] [Indexed: 05/20/2023]
Abstract
The risk assessment of mercury (Hg), in both humans and wildlife, is made challenging by great variability in exposure and health effects. Although disease risk arises following complex interactions between genetic ("nature") and environmental ("nurture") factors, most Hg studies thus far have focused solely on environmental factors. In recent years, ecogenetic-based studies have emerged and have started to document genetic and epigenetic factors that may indeed influence the toxicokinetics or toxicodynamics of Hg. The present study reviews these studies and discusses their utility in terms of Hg risk assessment, management, and policy and offers perspectives on fruitful areas for future research. In brief, epidemiological studies on populations exposed to inorganic Hg (e.g., dentists and miners) or methylmercury (e.g., fish consumers) are showing that polymorphisms in a number of environmentally responsive genes can explain variations in Hg biomarker values and health outcomes. Studies on mammals (wildlife, humans, rodents) are showing Hg exposures to be related to epigenetic marks such as DNA methylation. Such findings are beginning to increase understanding of the mechanisms of action of Hg, and in doing so they may help identify candidate biomarkers and pinpoint susceptible groups or life stages. Furthermore, they may help refine uncertainty factors and thus lead to more accurate risk assessments and improved decision-making.
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Affiliation(s)
- Niladri Basu
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA; Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec, Canada
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Baj G, Carlino D, Gardossi L, Tongiorgi E. Toward a unified biological hypothesis for the BDNF Val66Met-associated memory deficits in humans: a model of impaired dendritic mRNA trafficking. Front Neurosci 2013; 7:188. [PMID: 24198753 PMCID: PMC3812868 DOI: 10.3389/fnins.2013.00188] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 09/29/2013] [Indexed: 01/12/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) represents promotesa key molecule for the survival and differentiation of specific populations of neurons in the central nervous system. BDNF also regulates plasticity-related processes underlying memory and learning. A common single nucleotide polymorphism (SNP) rs6265 has been identified on the coding sequence of human BDNF located at 11p13. The SNP rs6265 is a single base mutation with an adenine instead of a guanine at position 196 (G196A), resulting in the amino acid substitution Val66Met. This polymorphism only exists in humans and has been associated with a plethora of effects ranging from molecular, cellular and brain structural modifications in association with deficits in social and cognitive functions. To date, the literature on Val66Met polymorphism describes a complex and often conflicting pattern of effects. In this review, we attempt to provide a unifying model of the Val66Met effects. We discuss the clinical evidence of the association between Val66Met and memory deficits, as well as the molecular mechanisms involved including the reduced transport of BDNF mRNA to the dendrites as well as the reduced processing and secretion of BDNF protein through the regulated secretory pathway.
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Affiliation(s)
- Gabriele Baj
- Department of Life Sciences, Brain Centre for Neurosciences, University of Trieste Trieste, Italy
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Wang Y, Goodrich JM, Werner R, Gillespie B, Basu N, Franzblau A. Relationship of estimated dietary intake of n-3 polyunsaturated fatty acids from fish with peripheral nerve function after adjusting for mercury exposure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 454-455:73-78. [PMID: 23538138 PMCID: PMC3640748 DOI: 10.1016/j.scitotenv.2013.02.075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 02/25/2013] [Accepted: 02/25/2013] [Indexed: 05/27/2023]
Abstract
BACKGROUND Some clinical studies have suggested that ingestion of n-3 polyunsaturated fatty acids (PUFA) has neuroprotective effects on peripheral nerve function. However, few epidemiological studies have examined the effect of dietary n-3 PUFA intake from fish consumption on peripheral nerve function, and none have controlled for co-occurrence of methylmercury exposure from fish consumption. OBJECTIVES We evaluated the effect of estimated dietary n-3 PUFA intake on peripheral nerve function after adjusting for biomarkers of methylmercury and elemental mercury in a convenience sample of 515 dental professionals. METHODS We measured sensory nerve conduction (peak latency and amplitude) of the median, ulnar and sural nerves and total mercury concentrations in hair and urine samples. We estimated daily intake (mg/day) of the total n-3 PUFA, n-3 docosahexaenoic acid (DHA), and n-3 eicosapentaenoic acid (EPA) based on a self-administrated fish consumption frequency questionnaire. We also collected information on mercury exposure, demographics and other covariates. RESULTS The estimated median intakes of total n-3 PUFA, n-3 EPA, and n-3 DHA were 447, 105, and 179 mg/day, respectively. The mean mercury concentrations in urine (1.05 μg/L) and hair (0.49 μg/g) were not significantly different from the US general population. We found no consistent association between n-3 PUFA intake and sensory nerve conduction after adjusting for mercury concentrations in hair and urine although some positive associations were observed with the sural nerve. CONCLUSIONS In a convenience sample of dental professionals, we found little evidence suggesting that dietary intake of n-3 PUFAs from fish has any impact on peripheral nerve function after adjustment for methylmercury exposure from fish and elemental mercury exposure from dental amalgam.
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Affiliation(s)
- Yi Wang
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor
| | - Jaclyn M. Goodrich
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor
| | - Robert Werner
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor
- Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI USA 48109
| | - Brenda Gillespie
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor
| | - Niladri Basu
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor
| | - Alfred Franzblau
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor
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Ruelas-Inzunza J, Delgado-Alvarez C, Frías-Espericueta M, Páez-Osuna F. Mercury in the atmospheric and coastal environments of Mexico. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2013; 226:65-99. [PMID: 23625130 DOI: 10.1007/978-1-4614-6898-1_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In Mexico, published studies relating to the occurrence of Hg in the environment are limited. Among the main sources of Hg in Mexico are mining and refining of Auand Hg, chloralkali plants, Cu smelting, residential combustion of wood, carbo electric plants, and oil refineries. Hg levels are highly variable in the atmospheric compartment because of the atmospheric dynamics and ongoing metal exchange with the terrestrial surface. In atmospheric studies, Hg levels are usually reported as total gaseous Hg (TGM). In Mexico, TGM values ranged from 1.32 ng m-3 in Hidalgo state (a rural agricultural area) to 71.82 ng m-3 in Zacatecas state (an area where brick manufacturers use mining wastes as a raw material).Published information on mercury levels in the coastal environment comprise 21 studies, representing 21 areas, in which sediments constituted the substrate that was analyzed for Hg. In addition, water samples were analyzed for Hg in nine studies.Few studies exist on Hg levels in the Caribbean and in the southwest of the country where tourism is rapidly increasing. Hence, there is a need for establishing baseline levels of mercury in these increasingly visited areas. In regions where studies have been undertaken, Hg levels in sediments were highly variable. Variations in Hg sediment levels mainly result from geological factors and the varying degree of anthropogenic impacts in the studied areas. In areas that still have pristine or nearly pristine environments (e.g., coast, Baja California, Todos Santos Bay, and La Paz lagoon), sediment Hg levels ranged from <0.006 to 0.35 j.lg g-1 on a dry wt basis.When higher levels exist (0.34-57.94 j.lg g-1 on a dry wt basis), the environment generally shows the influence of inputs from mining, oil processing, agriculture,geothermal events, or harmful algal bloom events (e.g., Guaymas Bay and Coatzacoalcos estuary). From chronological studies performed in selected coastal lagoons in NW Mexico, it is clear that Hg fluxes to sediments have increased from2- to 15-fold in recent years. Since the 1940s, historical increases of Hg fluxes have resulted from higher agricultural waste releases and exhaust from the thermo electric plants. The levels of Hg in water reveal a moderate to elevated contamination of some Mexican coastal sites. In Urias lagoon (NW Mexico), moderate to high levels were found in the dissolved and suspended fraction, and these are related to shipping, the fishing industry, domestic effluents, and the presence of a thermoelectric plant. In Coatzacoalcos (SE Mexico), extremely elevated Hg levels were found during the decade of the 1970s. Low to moderate levels of Hg were measured in waters from the Alvarado lagoon (SE Mexico); those concentrations appear to be associated with river waters that became enriched with organic matter and suspended solids inthe brackish mixing zone.Regarding the Hg content in invertebrates, the use of bivalves (oysters and mussels)as biomonitors must be established along the coastal zones of Mexico, because some coastal lagoons have not been previously monitored. In addition, more research is needed to investigate shrimp farms that are associated with agricultural basins and receive effluents from several anthropogenic sources (e.g., mining activity and urban discharges). Hg residues in several vertebrate groups collected in Mexico have been studied.These include mammals, birds, reptiles, and fish. In elasmobranch species, the highest Hg concentration (27.2 flg g-1 dry wt) was found in the muscle of the smooth hammer head shark (Sphyrna zygaena). Teleost fish are the vertebrate group that has been most studied, with regard to Hg residue content; the highest value (5.67 11g g-1dry wt) was detected in the striped marlin (T. audax). Among reptiles, only marine turtles were studied; Hg levels found ranged from 0.795 in the liver to 0.0006flg g-1dry wt in the blood of L. olivacea. In birds, the highest Hg concentration (5.08 flg g-1dry wt) detected was in the liver of the olivaceous cormorant (P. olivaceous).Specimens from stranded marine mammals were also analyzed; levels of Hg ranged from 70.35 flg g-1 dry wt in the liver of stranded spinner dolphin (S. longirostris ), to0.145 flg g-1 dry wt in the muscle of gray whale (E. robustus). The presence of Hgin these marine animals is not thought to have caused the stranding of the animals.Other organisms like macroalgae and vestimentiferan tube worms were used to monitor the occurrence of Hg in the aquatic environment; levels were comparable to data reported on similar organisms from other areas of the world. Few investigation shave been carried out concerning the mercury content in human organs/tissues in Mexico. Considering the potential deleterious effects of Hg on kidney, lung, and the central nervous system, more information about human exposure to organic and inorganic forms of mercury and their effects is needed, both in Mexico and elsewhere.
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Kauppi K, Nilsson LG, Adolfsson R, Lundquist A, Eriksson E, Nyberg L. Decreased medial temporal lobe activation in BDNF (66)Met allele carriers during memory encoding. Neuropsychologia 2012; 51:2462-8. [PMID: 23211991 DOI: 10.1016/j.neuropsychologia.2012.11.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 11/12/2012] [Accepted: 11/17/2012] [Indexed: 11/29/2022]
Abstract
The Met allele of the Brain-derived neurotrophic factor (BDNF) Val(66)Met polymorphism has been associated with impaired activity-dependent secretion of BDNF protein and decreased memory performance. Results from imaging studies relating Val(66)Met to brain activation during memory processing have been inconsistent, with reports of both increased and decreased activation in the Medial Temporal Lobe (MTL) in Met carriers relative to Val homozygotes. Here, we extensively studied BDNF Val(66)Met in relation to brain activation and white matter integrity as well as memory performance in a large imaging (n=194) and behavioral (n=2229) sample, respectively. Functional magnetic resonance imaging (fMRI) was used to investigate MTL activation in healthy participants in the age of 55-75 years during a face-name episodic encoding and retrieval task. White matter integrity was measured using diffusion tensor imaging. BDNF Met allele carriers had significantly decreased activation in the MTL during encoding processes, but not during retrieval processes. In contrast to previous proposals, the effect was not modulated by age and the polymorphism was not related to white matter integrity. Met carriers had lower memory performance than Val homozygotes, but differences were subtle and not significant. In conclusion, the BDNF Met allele has a negative influence on MTL functioning, preferentially during encoding processes, which might translate into impaired episodic memory function.
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Affiliation(s)
- Karolina Kauppi
- Department of Integrative Medical Biology (Physiology) Umeå University, SE-90187, Umeå, Sweden and Umeå Center for Functional Brain Imaging (UFBI), Umeå, Sweden.
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Effect of BDNF val66met polymorphism on declarative memory and its neural substrate: A meta-analysis. Neurosci Biobehav Rev 2012; 36:2165-77. [DOI: 10.1016/j.neubiorev.2012.07.002] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 03/16/2012] [Accepted: 07/07/2012] [Indexed: 12/27/2022]
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Romanowicz M, Ehlers S, Walker D, Decker P, Rundell J, Shinozaki G, Litzow M, Hogan W, Mrazek D, Black JL. Testing a Diathesis-Stress Model: Potential Genetic Risk Factors for Development of Distress in Context of Acute Leukemia Diagnosis and Transplant. PSYCHOSOMATICS 2012; 53:456-62. [DOI: 10.1016/j.psym.2012.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 01/05/2012] [Accepted: 01/05/2012] [Indexed: 12/25/2022]
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Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM. Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol 2012; 34:513-21. [PMID: 22765978 DOI: 10.1016/j.ntt.2012.06.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 06/22/2012] [Accepted: 06/23/2012] [Indexed: 12/15/2022]
Abstract
Mercury (Hg) is neurotoxic, and children may be particularly susceptible to this effect. A current major challenge is the identification of children who may be uniquely susceptible to Hg toxicity because of genetic disposition. We examined the hypothesis that CPOX4, a genetic variant of the heme pathway enzyme coproporphyrinogen oxidase (CPOX) that affects susceptibility to mercury toxicity in adults, also modifies the neurotoxic effects of Hg in children. Five hundred seven children, 8-12 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral effects of Hg from dental amalgam tooth fillings in children. Subjects were evaluated at baseline and at 7 subsequent annual intervals for neurobehavioral performance and urinary mercury levels. Following the completion of the clinical trial, genotyping assays for CPOX4 allelic status were performed on biological samples provided by 330 of the trial participants. Regression modeling strategies were employed to evaluate associations between CPOX4 status, Hg exposure, and neurobehavioral test outcomes. Among girls, few significant CPOX4-Hg interactions or independent main effects for Hg or CPOX4 were observed. In contrast, among boys, numerous significant interaction effects between CPOX4 and Hg were observed spanning all 5 domains of neurobehavioral performance. All underlying dose-response associations between Hg exposure and test performance were restricted to boys with the CPOX4 variant, and all of these associations were in the expected direction where increased exposure to Hg decreased performance. These findings are the first to demonstrate genetic susceptibility to the adverse neurobehavioral effects of Hg exposure in children. The paucity of responses among same-age girls with comparable Hg exposure provides evidence of sexual dimorphism in genetic susceptibility to the adverse neurobehavioral effects of Hg in children and adolescents.
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Affiliation(s)
- James S Woods
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA.
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Alfimova MV, Korovaitseva GI, Lezheiko TV, Golimbet VE. Effect of BDNF Val66Met Polymorphism on Normal Variability of Executive Functions. Bull Exp Biol Med 2012; 152:606-9. [DOI: 10.1007/s10517-012-1587-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wang Y, Goodrich JM, Gillespie B, Werner R, Basu N, Franzblau A. An investigation of modifying effects of metallothionein single-nucleotide polymorphisms on the association between mercury exposure and biomarker levels. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:530-4. [PMID: 22233731 PMCID: PMC3339459 DOI: 10.1289/ehp.1104079] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 01/09/2012] [Indexed: 05/19/2023]
Abstract
BACKGROUND Recent studies have suggested that several genes that mediate mercury metabolism are polymorphic in humans. OBJECTIVE We hypothesized that single-nucleotide polymorphisms (SNPs) in metallothionein (MT) genes may underlie interindividual differences in mercury biomarker levels. We studied the potential modifying effects of MT SNPs on mercury exposure-biomarker relationships. METHODS We measured total mercury in urine and hair samples of 515 dental professionals. We also surveyed occupational and personal exposures to dental amalgam and dietary fish consumption, from which daily methylmercury (MeHg) intake was estimated. Log-transformed urine and hair levels were modeled in multivariable linear regression separately against respective exposure surrogates, and the effect modification of 13 MT SNPs on exposure was investigated. RESULTS The mean mercury levels in urine (1.06 μg/L) and hair (0.51 μg/g) were not significantly different from the U.S. general population (0.95 μg/L and 0.47 μg/g, respectively). The mean estimated daily MeHg intake was 0.084 μg/kg/day (range, 0-0.98 μg/kg/day), with 25% of study population intakes exceeding the current U.S. Environmental Protection Agency reference dose of 0.1 μg/kg/day. Multivariate regression analysis showed that subjects with the MT1M (rs2270837) [corrected] AA genotype (n = 10) or the MT2A (rs10636) CC genotype (n = 42) had lower urinary mercury levels than did those with the MT1M or MT2A GG genotype (n = 329 and 251, respectively) after controlling for exposure and potential confounders. After controlling for MeHg intake, subjects with MT1A (rs8052394) GA and GG genotypes (n = 24) or the MT1M (rs9936741) TT genotype (n = 459) had lower hair mercury levels than did subjects with MT1A AA (n = 113) or MT1M TC and CC genotypes (n = 15), respectively. CONCLUSION Our findings suggest that some MT genetic polymorphisms may influence mercury biomarker concentrations at levels of exposure relevant to the general population.
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Affiliation(s)
- Yi Wang
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan 48109-2029, USA
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Wang Y, Goodrich JM, Werner R, Gillespie B, Basu N, Franzblau A. An investigation of modifying effects of single nucleotide polymorphisms in metabolism-related genes on the relationship between peripheral nerve function and mercury levels in urine and hair. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 417-418:32-8. [PMID: 22236634 PMCID: PMC3299006 DOI: 10.1016/j.scitotenv.2011.12.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 11/30/2011] [Accepted: 12/06/2011] [Indexed: 05/24/2023]
Abstract
Mercury (Hg) is a potent neurotoxicant. We hypothesized that single nucleotide polymorphisms (SNPs) in genes coding glutathione-related proteins, selenoproteins and metallothioneins may modify the relationship of mercury biomarkers with changes in peripheral nerve function. Dental professionals (n=515) were recruited in 2009 and 2010. Sensory nerve function (onset latency, peak latency and amplitude) of the median, ulnar and sural nerves was recorded. Samples of urine, hair and DNA were collected. Covariates related to demographics, nerve function and elemental and methyl-mercury exposure were also collected. Subjects included 244 dentists (47.4%) and 269 non-dentists (52.2%; mostly dental hygienists and dental assistants). The mean mercury levels in urine (1.06 μg/L) and hair (0.51 μg/g) were not significantly different from the US general population (0.95 μg/L and 0.47 μg/g, respectively). In multivariate linear models predicting nerve function adjusting for covariates, only 3 out of a total of 504 models showed stable and statistically significant interaction of SNPs with mercury biomarkers. Overall, given the possibility of false positives, the results suggested little evidence of effect modification of the SNPs on the relationship between mercury biomarkers with peripheral nerve function at exposure levels that are relevant to the general US population.
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Affiliation(s)
- Yi Wang
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI USA 48109
| | - Jaclyn M. Goodrich
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI USA 48109
| | - Robert Werner
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI USA 48109
- Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI USA 48109
| | - Brenda Gillespie
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI USA 48109
| | - Niladri Basu
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI USA 48109
| | - Alfred Franzblau
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI USA 48109
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Mandelman SD, Grigorenko EL. BDNF Val66Met and cognition: all, none, or some? A meta-analysis of the genetic association. GENES BRAIN AND BEHAVIOR 2011; 11:127-36. [PMID: 21980924 DOI: 10.1111/j.1601-183x.2011.00738.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The Val66Met, G196A (rs6265) polymorphism in the brain-derived neurotrophic factor gene, BDNF, located at 11p13, has been associated with a wide range of cognitive functions. Yet, the pattern of results is complex and conflicting. In this study, we conducted a meta-analysis that included 23 publications containing 31 independent samples comprised of 7095 individuals. The phenotypes that were examined in this analysis covered a wide variety of cognitive functions and included indicators of general cognitive ability, memory, executive function, visual processing skills and cognitive fluency. The meta-analysis did not establish significant genetic associations between the Val66Met polymorphism and any of the phenotypes that were included.
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Affiliation(s)
- S D Mandelman
- Human Development, Teachers College, Columbia University, New York, NY, USA
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OWHADI HOUMAN, BOULOS AREEN. BISTABLE EQUILIBRIUM POINTS OF MERCURY BODY BURDEN. J BIOL SYST 2011. [DOI: 10.1142/s0218339008002459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In the last century, mercury levels in the global environment have tripled as a result of increased pollution from industrial, occupational, medicinal and domestic uses.1 Glutathione is known to be the main agent responsible for the excretion of mercury (Refs. 2 to 4). It has also been shown that mercury inhibits glutathione synthetase (an enzyme acting in the synthesization of glutathione), therefore leading to decreased glutathione levels (Refs. 5 to 7). Mercury also interferes with the production of heme in the porphyrin pathway.8 Heme is needed for biological energy production and ability to detox organic toxins via the P450 enzymes.9 The purpose of this paper is to show that the body's response to mercury exposure is hysteretic, i.e. when this feedback of mercury on its main detoxifying agents is strong enough, then mercury body burden has two points of equilibrium: one with normal abilities to detoxify and low levels of mercury and one with inhibited abilities to detoxify and high levels of mercury. Furthermore, a small increase of the body's mercury burden may not be sufficient to trigger observable neurotoxic effects but it may be sufficient to act as a switch leading to an accumulation of mercury in the body through environmental exposure until its toxicity is manifested.
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Affiliation(s)
- HOUMAN OWHADI
- Applied and Computational Mathematics, and Control and Dynamical Systems, California Institute of Technology, MC 217-50, Pasadena, CA 91125, USA
| | - AREEN BOULOS
- Applied and Computational Mathematics, and Control and Dynamical Systems, California Institute of Technology, MC 217-50, Pasadena, CA 91125, USA
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Sletvold H, Svendsen K, Aas O, Syversen T, Hilt B. Neuropsychological function and past exposure to metallic mercury in female dental workers. Scand J Psychol 2011; 53:136-43. [PMID: 22092046 PMCID: PMC3412222 DOI: 10.1111/j.1467-9450.2011.00929.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The aim of this study was to see if dental personnel with previous exposure to metallic mercury have later developed disturbances in cognitive function. Ninety-one female participants who had been selected from a previous health survey of dental personnel were investigated neuropsychologically within the following domains: motor function, short-term memory, working memory, executive function, mental flexibility, and visual and verbal long-term memory. The scores were mainly within normal ranges. Relationships between an exposure score, the duration of employment before 1990, and previously measured mercury in urine as independent variables and the neuropsychological findings as dependent variables, were analyzed by multiple linear regression controlling for age, general ability, length of education, alcohol consumption, and previous head injuries. The only relationship that was statistically significant in the hypothesized direction was between the previously measured urine mercury values and visual long-term memory, where the urine values explained 30% of the variability. As the study had a low statistical power and also some other methodological limitations, the results have to be interpreted with caution. Even so, we think it is right to conclude that neuropsychological findings indicative of subsequent cognitive injuries are difficult to find in groups of otherwise healthy dental personnel with previous occupational exposure to mercury.
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Affiliation(s)
- Helge Sletvold
- Department of Industrial Economics and Technology Management, Norwegian University of Science and Technology, Trondheim, Norway
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Caserta D, Mantovani A, Ciardo F, Fazi A, Baldi M, Sessa MT, la Rocca C, Ronchi A, Moscarini M, Minoia C. Heavy metals in human amniotic fluid: a pilot study. Prenat Diagn 2011; 31:792-6. [DOI: 10.1002/pd.2768] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 01/21/2011] [Accepted: 03/25/2011] [Indexed: 12/11/2022]
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Rooney J. Further thoughts on mercury, epigenetics, genetics and amyotrophic lateral sclerosis. NEURODEGENER DIS 2011; 8:523-4. [PMID: 21411980 DOI: 10.1159/000324518] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 01/21/2011] [Indexed: 11/19/2022] Open
Affiliation(s)
- James Rooney
- Department of Pharmaceutical and Medicinal Chemistry, Royal College of Surgeons in Ireland, Dublin, Ireland. jrooney @ rcsi.ie
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Mutter J. Is dental amalgam safe for humans? The opinion of the scientific committee of the European Commission. J Occup Med Toxicol 2011; 6:2. [PMID: 21232090 PMCID: PMC3025977 DOI: 10.1186/1745-6673-6-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 01/13/2011] [Indexed: 01/06/2023] Open
Abstract
It was claimed by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR)) in a report to the EU-Commission that "....no risks of adverse systemic effects exist and the current use of dental amalgam does not pose a risk of systemic disease..." [1, available from: http://ec.europa.eu/health/ph_risk/committees/04_scenihr/docs/scenihr_o_016.pdf].SCENIHR disregarded the toxicology of mercury and did not include most important scientific studies in their review. But the real scientific data show that:(a) Dental amalgam is by far the main source of human total mercury body burden. This is proven by autopsy studies which found 2-12 times more mercury in body tissues of individuals with dental amalgam. Autopsy studies are the most valuable and most important studies for examining the amalgam-caused mercury body burden.(b) These autopsy studies have shown consistently that many individuals with amalgam have toxic levels of mercury in their brains or kidneys.(c) There is no correlation between mercury levels in blood or urine, and the levels in body tissues or the severity of clinical symptoms. SCENIHR only relied on levels in urine or blood.(d) The half-life of mercury in the brain can last from several years to decades, thus mercury accumulates over time of amalgam exposure in body tissues to toxic levels. However, SCENIHR state that the half-life of mercury in the body is only "20-90 days".(e) Mercury vapor is about ten times more toxic than lead on human neurons and with synergistic toxicity to other metals.(f) Most studies cited by SCENIHR which conclude that amalgam fillings are safe have severe methodical flaws.
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Affiliation(s)
- Joachim Mutter
- Department of Environmental and integrative medicine Lohnerhofstraße 2, 78467 Constance/Germany.
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