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Yohannes YB, Nakayama SM, Yabe J, Toyomaki H, Kataba A, Nakata H, Muzandu K, Ikenaka Y, Choongo K, Ishizuka M. Delta-aminolevulinic acid dehydratase (ALAD) and vitamin D receptor (VDR) genes polymorphisms in children residing in an abandoned lead‑zinc mine area in Kabwe, Zambia. Meta Gene 2021. [DOI: 10.1016/j.mgene.2020.100838] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Mani MS, Puranik A, Kabekkodu SP, Joshi MB, Dsouza HS. Influence of VDR and HFE polymorphisms on blood lead levels of occupationally exposed workers. Hum Exp Toxicol 2020; 40:897-914. [PMID: 33233953 DOI: 10.1177/0960327120975451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lead is a ubiquitous heavy metal toxin of significant public health concern. Every individual varies in their response to lead's toxic effects due to underlying genetic variations in lead metabolizing enzymes or proteins distributed in the population. Earlier studies, including our lab, have attributed the influence of ALAD (δ-Aminolevulinate dehydratase) polymorphism on blood lead retention and ALAD activity. The present study aimed to investigate the influence of VDR (Vitamin D receptor) and HFE (Hemochromatosis) polymorphisms in modulating blood lead levels (BLLs) of occupationally exposed workers. 164 lead-exposed subjects involved in lead alloy manufacturing and battery breaking and recycling processes and 160 unexposed controls with BLLs below 10 µg/dL recruited in the study. Blood lead levels, along with a battery of biochemical assays and genotyping, were performed. Regression analysis revealed a negative influence of BLLs on ALAD activity (p < 0.0001) and a positive influence on smokeless tobacco use (p < 0.001) in lead-exposed subjects. A predicted haplotype of the three VDR polymorphisms computed from genotyping data revealed that T-A-A haplotype increased the BLLs by 0.93 units (p ≤ 0.05) and C-C-A haplotype decreased the BLLs by 7.25 units (p ≤ 0.05). Further analysis revealed that the wild-type CC genotype of HFE H63D presented a higher median BLL, indicating that variant C allele may have a role in increasing the concentration of lead. Hence, the polymorphism of genes associated with lead metabolism might aid in predicting genetic predisposition to lead and its associated effects.
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Affiliation(s)
- Monica Shirley Mani
- Department of Radiation Biology and Toxicology, Manipal School of Life Sciences, 76793Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Amitha Puranik
- Department of Data Science, Prasanna School of Public Health, 76793Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Shama Prasada Kabekkodu
- Department of Cellular and Molecular Biology, Manipal School of Life Sciences, 76793Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Manjunath B Joshi
- Department of Ageing, Manipal School of Life Sciences, 76793Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Herman Sunil Dsouza
- Department of Radiation Biology and Toxicology, Manipal School of Life Sciences, 76793Manipal Academy of Higher Education, Manipal, Karnataka, India
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Liu HL, Chuang HY, Hsu CN, Lee SS, Yang CC, Liu KT. Effects of Vitamin D Receptor, Metallothionein 1A, and 2A Gene Polymorphisms on Toxicity of the Peripheral Nervous System in Chronically Lead-Exposed Workers. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E2909. [PMID: 32340109 PMCID: PMC7215364 DOI: 10.3390/ijerph17082909] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 01/23/2023]
Abstract
Chronic exposure to lead is neurotoxic to the human peripheral sensory system. Variant vitamin D receptor (VDR) genes and polymorphisms of metallothioneins (MTs) are associated with different outcomes following lead toxicity. However, no evidence of a relationship between lead neurotoxicity and polymorphisms has previously been presented. In this study, we investigated the relationship between the polymorphisms of VDR, MT1A, and MT2A genes and lead toxicity following chronic occupational lead exposure. We measured vibration perception thresholds (VPT) and current perception thresholds (CPT) in 181 workers annually for five years. The outcome variables were correlated to the subject's index of long-term lead exposure. Polymorphisms of VDR, MT1A, and MT2A were defined. The potential confounders, including age, sex, height, smoking, alcohol consumption, and working life span, were also collected and analyzed using linear regression. The regression coefficients of some gene polymorphisms were at least 20 times larger than regression coefficients of time-weighted index of cumulative blood lead (TWICL) measures. All regression coefficients of TWICL increased slightly. MT1A rs11640851 (AA/CC) was associated with a statistically significant difference in all neurological outcomes except hand and foot VPT. MT1A rs8052394 was associated with statistically significant differences in hand and foot CPT 2000 Hz. In MT2A rs10636, those with the C allele showed a greater effect on hand CPT than those with the G allele. Among the VDR gene polymorphisms, the Apa rs7975232 (CC/AA) single nucleotide polymorphism was associated with the greatest difference in hand CPT. MT2A rs28366003 appeared to have a neural protective effect, whereas Apa (rs7975232) of VDR and MT2A rs10636 increased the neurotoxicity as measured by CPT in the hands. MT1A rs8052394 had a protective effect on large myelinated nerves. MT1A rs11640851 was associated with susceptibility to neurotoxicity.
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Affiliation(s)
- Hsin-Liang Liu
- Division of Internal Medicine, Department of Emergency Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Hung-Yi Chuang
- Department of Public Health, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
- Department of Environmental and Occupational Medicine, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan;
| | - Chien-Ning Hsu
- Department of Pharmacy in Kaohsiung Chang Gung Memorial Hospital, and School of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Su-Shin Lee
- Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Chen-Cheng Yang
- Department of Environmental and Occupational Medicine, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan;
| | - Kuan-Ting Liu
- Division of Internal Medicine, Department of Emergency Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
- School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
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Mani MS, Kabekkodu SP, Joshi MB, Dsouza HS. Ecogenetics of lead toxicity and its influence on risk assessment. Hum Exp Toxicol 2019; 38:1031-1059. [PMID: 31117811 DOI: 10.1177/0960327119851253] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
Lead (Pb) toxicity is a public health problem affecting millions worldwide. Advances in 'omic' technology have paved the way to toxico-genomics which is currently revolutionizing the understanding of interindividual variations in susceptibility to Pb toxicity and its functional consequences to exposure. Our objective was to identify, comprehensively analyze, and curate all the potential genetic and epigenetic biomarkers studied to date in relation to Pb toxicity and its association with diseases. We screened a volume of research articles that focused on Pb toxicity and its association with genetic and epigenetic signatures in the perspective of occupational and environmental Pb exposure. Due to wide variations in population size, ethnicity, age-groups, and source of exposure in different studies, researchers continue to be skeptical on the topic of the influence of genetic variations in Pb toxicity. However, surface knowledge of the underlying genetic factors will aid in elucidating the mechanism of action of Pb. Moreover, in recent years, the application of epigenetics in Pb toxicity has become a promising area in toxicology to understand the influence of epigenetic mechanisms such as DNA methylation, chromatin remodeling, and small RNAs for the regulation of genes in response to Pb exposure during early life. Growing evidences of ecogenetic understanding (both genetic and epigenetic processes) in a dose-dependent manner may help uncover the mechanism of action of Pb and in the identification of susceptible groups. Such studies will further help in refining uncertainty factors and in addressing risk assessment of Pb poisoning.
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Affiliation(s)
- M S Mani
- 1 Department of Radiation Biology and Toxicology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - S P Kabekkodu
- 2 Department of Cellular and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - M B Joshi
- 3 Department of Ageing, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - H S Dsouza
- 1 Department of Radiation Biology and Toxicology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
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Shaik AP, Alsaeed AH, Faiyaz-Ul-Haque M, Alsaeed MA, Alyousef AA, Bammidi VK, Shaik AS. Vitamin D Receptor FokI, ApaI, and TaqI Polymorphisms in Lead Exposed Subjects From Saudi Arabia. Front Genet 2019; 10:388. [PMID: 31080460 PMCID: PMC6497804 DOI: 10.3389/fgene.2019.00388] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 04/10/2019] [Indexed: 12/14/2022] Open
Abstract
Vitamin D receptor (VDR) gene polymorphisms were reported to influence blood lead levels (BLL) and the response of subjects to the symptoms of lead toxicity. However, no studies have been conducted in the Saudi Arabian population which has unique ethnicity and socio-demographic features. This study examined the polymorphisms in exon 2 (allele 1) and intron 8 (allele 2 and allele 3) of VDR gene and their relation to BLLs. As per the CDC guidelines, the recruited lead-exposed workers (N = 130) were categorized to two groups viz., low BLL group (<10 μg/dL) and high BLL group (>10 μg/dL). The low BLL group had a mean BLL of 4.37 μg/dL, while the high BLL group had levels of 18.12 μg/dL (p < 0.001). Overall, the genetic variants, TC and CC in the VDR FokI were significantly associated with a risk of lead toxicity and the allele "C" was a risk factor (p = 0.00026). Furthermore, the TT genotype of VDR ApaI significantly increased the risk of developing lead poisoning (p = 0.0006). The VDR TaqI SNP was not significantly associated with lead toxicity. The highest BLLs for VDR FokI-CC, VDR ApaI-GG, and VDR TaqI-TT genotypes from High BLL group were 18.42, 15.26, and 18.75 μg/dL, respectively. Older age (51-60 years) was found to be a significant confounding factor for BLLs (p = 0.012). Additional studies in larger sample sizes are needed to firmly establish the role of VDR genotypes and genetic susceptibility to lead poisoning.
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Affiliation(s)
- Abjal Pasha Shaik
- Department of Clinical Laboratory Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Abbas H Alsaeed
- Department of Clinical Laboratory Sciences, King Saud University, Riyadh, Saudi Arabia
| | - M Faiyaz-Ul-Haque
- Department of Pathology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mikqdad A Alsaeed
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Abdullah A Alyousef
- Department of Clinical Laboratory Sciences, King Saud University, Riyadh, Saudi Arabia
| | | | - Asma Sultana Shaik
- Department of Clinical Laboratory Sciences, King Saud University, Riyadh, Saudi Arabia
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Use of Genetic Algorithm Combinational Single-nucleotide Polymorphisms Could Modify the Association of Blood Lead Levels and Bone Matrix Density. Epidemiology 2017; 28 Suppl 1:S121-S125. [PMID: 29028685 DOI: 10.1097/ede.0000000000000740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Previous studies have not explored the relationship between a single gene and a single disease. Our study aims to investigate the association of multiple genotypes with blood lead levels and bone matrix density (BMD) by using genetic algorithms. METHODS Our research focused on 506 employees (245 males and 261 females) of a lead battery factory in Taiwan. We collected data on their BMD, blood lead level, and 6 SNPs (ACE, alpha-adducin, Bsm, Tag, Apa, and ALAD); these factors were analyzed using discrete binary particle swarm optimization (DBPSO) and logistic regression analysis. RESULTS We found no association between blood lead level and bone density, which may be due to the relatively young age of this population (mean age = 45.1 years). However, the genotype that contained both Bsm type bb and ALAD type 1-1 may play an important role in protecting against lower bone density among these employees. CONCLUSIONS In conclusion, this study found that the Bsm and ALAD genes influence bone density among lead workers. However, the mechanism and exact relationship between these two genes and bone density require further investigation.
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Does maternal VDR FokI single nucleotide polymorphism have an effect on lead levels of placenta, maternal and cord bloods? Placenta 2015; 36:870-5. [DOI: 10.1016/j.placenta.2015.06.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 06/23/2015] [Accepted: 06/25/2015] [Indexed: 11/20/2022]
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Gottesfeld P, Pokhrel AK. Review: Lead exposure in battery manufacturing and recycling in developing countries and among children in nearby communities. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2011; 8:520-32. [PMID: 21793732 DOI: 10.1080/15459624.2011.601710] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The battery industry is the largest consumer of lead, using an estimated 80% of the global lead production. The industry is also rapidly expanding in emerging market countries. A review of published literature on exposures from lead-acid battery manufacturing and recycling plants in developing countries was conducted. The review included studies from 37 countries published from 1993 to 2010 and excluded facilities in developed countries, such as the United States and those in Western Europe, except for providing comparisons to reported findings. The average worker blood lead level (BLL) in developing countries was 47 μg/dL in battery manufacturing plants and 64 μg/dL in recycling facilities. Airborne lead concentrations reported in battery plants in developing countries averaged 367 μg/m3, which is 7-fold greater than the U.S. Occupational Safety and Health Administration's 50 μg/m3 permissible exposure limit. The geometric mean BLL of children residing near battery plants in developing countries was 19 μg/dL, which is about 13-fold greater than the levels observed among children in the United States. The blood lead and airborne lead exposure concentrations for battery workers were substantially higher in developing countries than in the United States. This disparity may worsen due to rapid growth in lead-acid battery manufacturing and recycling operations worldwide. Given the lack of regulatory and enforcement capacity in most developing countries, third-party certification programs may be the only viable option to improve conditions.
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Affiliation(s)
- Perry Gottesfeld
- Occupational Knowledge International, San Francisco, California 94118, USA.
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A transdisciplinary perspective of chronic stress in relation to psychopathology throughout life span development. Dev Psychopathol 2011; 23:725-76. [DOI: 10.1017/s0954579411000289] [Citation(s) in RCA: 170] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
AbstractThe allostatic load (AL) model represents an interdisciplinary approach to comprehensively conceptualize and quantify chronic stress in relation to pathologies throughout the life cycle. This article first reviews the AL model, followed by interactions among early adversity, genetics, environmental toxins, as well as distinctions among sex, gender, and sex hormones as integral antecedents of AL. We next explore perspectives on severe mental illness, dementia, and caregiving as unique human models of AL that merit future investigations in the field of developmental psychopathology. A complimenting transdisciplinary perspective is applied throughout, whereby we argue that the AL model goes beyond traditional stress–disease theories toward the advancement of person-centered research and practice that promote not only physical health but also mental health.
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Rezende VB, Amaral JH, Quintana SM, Gerlach RF, Barbosa F, Tanus-Santos JE. Vitamin D receptor haplotypes affect lead levels during pregnancy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:4955-4960. [PMID: 20692022 DOI: 10.1016/j.scitotenv.2010.07.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 07/03/2010] [Accepted: 07/14/2010] [Indexed: 05/29/2023]
Abstract
Pregnant women are particularly susceptible to toxic effects associated with lead (Pb) exposure. Pb accumulates in bone tissue and is rapidly mobilized from bones during pregnancy, thus resulting in fetal contamination. While vitamin D receptor (VDR) polymorphisms modify bone mineralization and affect Pb biomarkers including blood (Pb-B) and serum (Pb-S) Pb concentrations, and %Pb-S/Pb-B ratio, the effects of these polymorphisms on Pb levels in pregnant women are unknown. This study aimed at examining the effects of three (FokI, BsmI and ApaI) VDR polymorphisms (and VDR haplotypes) on Pb levels in pregnant women. Pb-B and Pb-S were determined by inductively coupled plasma mass spectrometry in samples from 256 healthy pregnant women and their respective umbilical cords. Genotypes for the VDR polymorphisms were determined by PCR and restriction fragment length digestion. While the three VDR polymorphisms had no significant effects on Pb-B, Pb-S or %Pb-S/Pb-B ratio, the haplotype combining the f, a, and b alleles for the FokI, ApaI and BsmI polymorphisms, respectively, was associated with significantly lower Pb-S and %Pb-S/Pb-B (P<0.05). However, maternal VDR haplotypes had no effects on Pb levels in the umbilical cords. To our knowledge, this is the first study showing that a combination of genetic polymorphisms (haplotype) commonly found in the VDR gene affects Pb-S and %Pb-S/Pb-B ratios in pregnant women. These findings may have major implications for Pb toxicity because they may help to predict the existence of a group of subjects that is genetically less prone to Pb toxicity during pregnancy.
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Affiliation(s)
- Vania B Rezende
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 13081-970, Campinas, SP, Brazil
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Krieg EF, Butler MA, Chang MH, Liu T, Yesupriya A, Dowling N, Lindegren ML. Lead and cognitive function in VDR genotypes in the third National Health and Nutrition Examination Survey. Neurotoxicol Teratol 2009; 32:262-72. [PMID: 20006704 DOI: 10.1016/j.ntt.2009.12.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 11/10/2009] [Accepted: 12/07/2009] [Indexed: 01/08/2023]
Abstract
The relationship between the blood lead concentration and cognitive function in children and adults with different VDR genotypes who participated in the third National Health and Nutrition Examination Survey was investigated. The relationship between blood lead and serum homocysteine concentrations was also investigated. In children 12 to 16 years old, performance on the digit span and arithmetic tests as a function of the blood lead concentration varied by VDR rs2239185 and VDR rs731236 genotypes. Decreases in performance occurred in some genotypes, but not in others. In adults 20 to 59 years old, performance on the symbol-digit substitution test as a function of the blood lead concentration varied by VDR rs2239185-rs731236 haplotype. In the 12 to 16 year old children and adults 60 or more years old, the relationship between the serum homocysteine and blood lead concentrations varied by VDR genotype. The mean blood lead concentrations of the children and adults did not vary by VDR genotype.
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Affiliation(s)
- Edward F Krieg
- National Institute for Occupational Safety and Health, Cincinnati, Ohio 45226, USA.
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Rezende VB, Barbosa F, Montenegro MF, Sandrim VC, Gerlach RF, Tanus-Santos JE. Haplotypes of vitamin D receptor modulate the circulating levels of lead in exposed subjects. Arch Toxicol 2007; 82:29-36. [PMID: 17701399 DOI: 10.1007/s00204-007-0231-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Accepted: 07/27/2007] [Indexed: 02/06/2023]
Abstract
Genetic factors influence whole blood lead (Pb-B) concentrations in lead exposed subjects. This study aimed at examining the combined effects (haplotype analysis) of three polymorphisms (BsmI, ApaI and FokI) in vitamin D receptor (VDR) gene on Pb-B and on the concentrations of lead in plasma (Pb-P), which is more relevant to lead toxicity, in 150 environmentally exposed subjects. Genotypes were determined by RFLP, and Pb-P and Pb-B were determined by inductively coupled plasma mass spectrometry and by graphite furnace atomic absorption spectrometry, respectively. Subjects with the bb (BsmI polymorphism) or ff (FokI polymorphism) genotypes have lower B-Pb than subjects in the other genotype groups. Subjects with the aa (ApaI polymorphism) or ff genotypes have lower P-Pb than subjects in the other genotype groups. Lower Pb-P, Pb-B, and %Pb-P/Pb-B levels were found in subjects with the haplotype combining the a, b, and f alleles for the ApaI, BsmI, and FokI polymorphisms, respectively, compared with the other haplotype groups, thus suggesting that VDR haplotypes modulate the circulating levels of lead in exposed subjects.
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Affiliation(s)
- Vania B Rezende
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 13081-970 Campinas, SP, Brazil
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Weaver VM, Lee BK, Todd AC, Ahn KD, Shi W, Jaar BG, Kelsey KT, Lustberg ME, Silbergeld EK, Parsons PJ, Wen J, Schwartz BS. Effect modification by delta-aminolevulinic acid dehydratase, vitamin D receptor, and nitric oxide synthase gene polymorphisms on associations between patella lead and renal function in lead workers. ENVIRONMENTAL RESEARCH 2006; 102:61-9. [PMID: 16487505 DOI: 10.1016/j.envres.2006.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Revised: 12/19/2005] [Accepted: 01/04/2006] [Indexed: 05/06/2023]
Abstract
Genetic polymorphisms that affect lead toxicokinetics or toxicodynamics may be important modifiers of risk for adverse outcomes in lead-exposed populations. We recently reported associations between higher patella lead, which is hypothesized to represent a lead pool that is both bioavailable and cumulative, and adverse renal outcomes in current and former Korean lead workers. In the present study, we assessed effect modification by polymorphisms in the genes encoding for delta-aminolevulinic acid dehydratase (ALAD), the vitamin D receptor (VDR), and endothelial nitric oxide synthase on those associations. Similar analyses were conducted with three other lead biomarkers. Renal function was assessed via blood urea nitrogen, serum creatinine, measured and calculated creatinine clearances, urinary N-acetyl-beta-D-glucosaminidase, and retinol-binding protein. Mean (SD) blood, patella, tibia, and dimercaptosuccinic acid-chelatable lead values were 30.9 (16.7) microg/dl, 75.1 (101.1)and 33.6 (43.4) microg Pb/g bone mineral, and 0.63 (0.75) microg Pb/mg creatinine, respectively, in 647 lead workers. Little evidence of effect modification by genotype on associations between patella lead and renal outcomes was observed. The VDR polymorphism did modify associations between the other lead biomarkers and the serum creatinine and calculated creatinine clearance. Higher lead dose was associated with worse renal function in participants with the variant B allele. Models in two groups, dichotomized by median age, showed that this effect was present in the younger half of the population. Limited evidence of effect modification by ALAD genotype was observed; higher blood lead levels were associated with higher calculated creatinine clearance among participants with the ALAD(1-2) genotype. In conclusion, VDR and/or ALAD genotypes modified associations between all the lead biomarkers, except patella lead, and the renal outcomes.
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Affiliation(s)
- Virginia M Weaver
- Division of Occupational and Environmental Health, Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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