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Pamphlett R, Bishop DP. Mercury is present in neurons and oligodendrocytes in regions of the brain affected by Parkinson's disease and co-localises with Lewy bodies. PLoS One 2022; 17:e0262464. [PMID: 35015796 PMCID: PMC8752015 DOI: 10.1371/journal.pone.0262464] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 12/24/2021] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Environmental toxicants are suspected to play a part in the pathogenesis of idiopathic Parkinson's disease (PD) and may underlie its increasing incidence. Mercury exposure in humans is common and is increasing due to accelerating levels of atmospheric mercury, and mercury damages cells via oxidative stress, cell membrane damage, and autoimmunity, mechanisms suspected in the pathogenesis of PD. We therefore compared the cellular distribution of mercury in the tissues of people with and without PD who had evidence of previous mercury exposure by mercury being present in their locus ceruleus neurons. MATERIALS AND METHODS Paraffin sections from the brain and general organs of two people with PD, two people without PD with a history of mercury exposure, and ten people without PD or known mercury exposure, were stained for inorganic mercury using autometallography, combined with immunostaining for a-synuclein and glial cells. All had mercury-containing neurons in locus ceruleus neurons. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to confirm the presence of mercury and to look for other potentially toxic elements. Autometallography-stained locus ceruleus paraffin sections were examined to compare the frequency of previous mercury exposure between 20 PD and 40 non-PD individuals. RESULTS In PD brains, autometallography-detected mercury was seen in neurons affected by the disease, such as those in the substantia nigra, motor cortex, striatum, thalamus, and cerebellum. Mercury was seen in oligodendrocytes in white and grey matter. Mercury often co-localised with Lewy bodies and neurites. A more restricted distribution of brain mercury was seen in people without PD (both with or without known mercury exposure), with no mercury present in the substantia nigra, striatum, or thalamus. The presence of autometallography-detected mercury in PD was confirmed with LA-ICP-MS, which demonstrated other potentially toxic metals in the locus ceruleus and high iron levels in white matter. Autometallography-detected mercury was found in locus ceruleus neurons in a similar proportion of PD (65%) and non-PD (63%) individuals. CONCLUSIONS In people with PD, mercury was found in neurons and oligodendrocytes in regions of the brain that are affected by the disease, and often co-localised with aggregated a-synuclein. Mercury in the motor cortex, thalamus and striatum could result in bradykinesia and rigidity, and mercury in the cerebellum could cause tremor. People without PD had a restricted uptake of mercury into the brain. The similar frequency of mercury in the locus ceruleus of people with and without PD suggests these two groups have had comparable previous mercury exposures but that PD brains have a greater predisposition to take up circulating mercury. While this post mortem study does not provide a direct link between mercury and idiopathic PD, it adds to the body of evidence that metal toxicants such as mercury play a role in the disease. A precautionary approach would be to reduce rising mercury levels in the atmosphere by limiting the burning of fossil fuels, which may be contributing to the increasing incidence of PD.
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Affiliation(s)
- Roger Pamphlett
- Sydney Medical School, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
- Department of Neuropathology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
- * E-mail:
| | - David P. Bishop
- Elemental Bio-Imaging Facility, School of Mathematical and Physical Sciences, University of Technology Sydney, Sydney, New South Wales, Australia
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Torti M, Fossati C, Casali M, De Pandis MF, Grassini P, Radicati FG, Stirpe P, Vacca L, Iavicoli I, Leso V, Ceppi M, Bruzzone M, Bonassi S, Stocchi F. Effect of family history, occupation and diet on the risk of Parkinson disease: A case-control study. PLoS One 2020; 15:e0243612. [PMID: 33332388 PMCID: PMC7746265 DOI: 10.1371/journal.pone.0243612] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/25/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The aetiology of Parkinson's disease (PD) is still very controversial, with a peculiar lack of established risk factors or protective behavior. METHODS We carried out a case-control study of 634 idiopathic PD patients admitted from 2011 to 2015 to two hospitals located in central Italy and 532 controls matched by hospital, gender and age (± 5 years). The study questionnaire included questions on host factors, family history, residence, occupation and lifestyle. Odds ratios (ORs) for PD and 95% confidence intervals (CIs) were estimated with logistic regression, adjusting for actual and potential confounders. RESULTS A lower OR was observed in females (0.74; 95%CI:0.58-0.96), while older age classes showed a constantly increased risk for PD (p<0.005) starting from the class 65-69 years. Subjects who reported a first degree relative affected by PD showed a borderline increase which was more evident in those enrolled in the urban center of Rome (OR = 1.65; 95%CI: 1.09-2.50). Significant reduction of the risk was associated to current smoking (OR = 0.48; 95%CI: 0.24-0.54), and to vegetables consumption (p<0.03), while borderline increases were associated to meat and cold cut consumption. Occupational activities classified according to ISCO-08 categories did not show increased risk, while higher ORs' were found for pilots and physicians. CONCLUSIONS The results from this study confirmed the higher risk of PD in males and in elderly, and the inverse association with smoking habit. The possible etiological role of familial clustering, dietary habit, and some job tasks is suggested.
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Affiliation(s)
- Margherita Torti
- San Raffaele Pisana Institute for Research and Medical Care, Clinical Trial Center, Rome, Italy
- * E-mail:
| | - Chiara Fossati
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Miriam Casali
- San Raffaele Pisana Institute for Research and Medical Care, Clinical Trial Center, Rome, Italy
| | | | - Paola Grassini
- San Raffaele Pisana Institute for Research and Medical Care, Clinical Trial Center, Rome, Italy
| | - Fabiana Giada Radicati
- San Raffaele Pisana Institute for Research and Medical Care, Clinical Trial Center, Rome, Italy
| | - Paola Stirpe
- San Raffaele Pisana Institute for Research and Medical Care, Clinical Trial Center, Rome, Italy
| | - Laura Vacca
- San Raffaele Pisana Institute for Research and Medical Care, Clinical Trial Center, Rome, Italy
| | - Ivo Iavicoli
- Department of Public Health University of Naples Federico II, Naples, Italy
| | - Veruscka Leso
- Department of Public Health University of Naples Federico II, Naples, Italy
| | - Marcello Ceppi
- Unit of Clinical Epidemiology, Ospedale Policlinico San Martino, Genoa, Italy
| | - Marco Bruzzone
- Unit of Clinical Epidemiology, Ospedale Policlinico San Martino, Genoa, Italy
| | - Stefano Bonassi
- Unit of Clinical and Molecular Epidemiology, Institute for Research and Medical Care, San Raffaele Pisana, Rome, Italy
- Department of Human Sciences and Quality of Life Promotion, San Raffaele University, Rome, Italy
| | - Fabrizio Stocchi
- San Raffaele Pisana Institute for Research and Medical Care, Clinical Trial Center, Rome, Italy
- Department of Human Sciences and Quality of Life Promotion, San Raffaele University, Rome, Italy
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Zhang C, Hou L, Yang J, Che Y, Sun F, Li H, Wang Q. 2,5-Hexanedione induces dopaminergic neurodegeneration through integrin α Mβ2/NADPH oxidase axis-mediated microglial activation. Cell Death Dis 2018; 9:60. [PMID: 29352205 PMCID: PMC5833449 DOI: 10.1038/s41419-017-0091-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/08/2017] [Accepted: 10/23/2017] [Indexed: 02/06/2023]
Abstract
Recent study demonstrated that chronic exposure to solvents increases the risk of Parkinson's disease (PD), the second most common neurodegenerative disorder characterized by progressive dopaminergic neurodegeneration in the substantia nigra (SN). n-Hexane, a widely used organic solvent, displays central-peripheral neurotoxicity, which is mainly mediated by its active metabolite, 2,5-hexanedione (HD). However, whether HD exposure contributes to PD remains unclear. In this study, we found that rats exposed to HD displayed progressive dopaminergic neurodegeneration in the nigrostriatal system. Microglial activation was also detected in HD-treated rats, which occurred prior to degeneration of dopaminergic neurons. Moreover, depletion of microglia markedly reduced HD-induced dopaminergic neurotoxicity. Mechanistic study revealed an essential role of microglial integrin αMβ2-NADPH oxidase (NOX2) axis in HD-elicited neurotoxicity. HD activated NOX2 by inducing membrane translocation of NOX2 cytosolic subunit, p47phox. Integrin αMβ2 was critical for HD-induced NOX2 activation since inhibition or genetic deletion of αMβ2 attenuated NOX2-generated superoxide and p47phox membrane translocation in response to HD. Src and Erk, two downstream signals of αMβ2, were recognized to bridge HD/αMβ2-mediated NOX2 activation. Finally, pharmacological inhibition of αMβ2-NOX2 axis attenuated HD-induced microglial activation and dopaminergic neurodegeneration. Our findings revealed that HD exposure damaged nigrostriatal dopaminergic system through αMβ2-NOX2 axis-mediated microglial activation, providing, for the first time, experimental evidence for n-hexane exposure contributing to the etiology of PD.
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Affiliation(s)
- Cong Zhang
- 0000 0000 9558 1426grid.411971.bSchool of Public Health, Dalian Medical University, No. 9W. Lvshun South Road, Dalian, 116044 China
| | - Liyan Hou
- 0000 0000 9558 1426grid.411971.bSchool of Public Health, Dalian Medical University, No. 9W. Lvshun South Road, Dalian, 116044 China
| | - Jie Yang
- 0000 0000 9558 1426grid.411971.bSchool of Public Health, Dalian Medical University, No. 9W. Lvshun South Road, Dalian, 116044 China
| | - Yuning Che
- 0000 0000 9558 1426grid.411971.bSchool of Public Health, Dalian Medical University, No. 9W. Lvshun South Road, Dalian, 116044 China
| | - Fuqiang Sun
- 0000 0000 9558 1426grid.411971.bSchool of Public Health, Dalian Medical University, No. 9W. Lvshun South Road, Dalian, 116044 China
| | - Huihua Li
- 0000 0000 9558 1426grid.411971.bSchool of Public Health, Dalian Medical University, No. 9W. Lvshun South Road, Dalian, 116044 China ,grid.452435.1Department of Cardiology, Institute of Cardiovascular Diseases, First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Qingshan Wang
- 0000 0000 9558 1426grid.411971.bSchool of Public Health, Dalian Medical University, No. 9W. Lvshun South Road, Dalian, 116044 China
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Patel R, Bradner JM, Stout KA, Caudle WM. Alteration to Dopaminergic Synapses Following Exposure to Perfluorooctane Sulfonate (PFOS), in Vitro and in Vivo. Med Sci (Basel) 2016; 4:medsci4030013. [PMID: 29083377 PMCID: PMC5635798 DOI: 10.3390/medsci4030013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/04/2016] [Accepted: 08/09/2016] [Indexed: 12/30/2022] Open
Abstract
Our understanding of the contribution exposure to environmental toxicants has on neurological disease continues to evolve. Of these, Parkinson’s disease (PD) has been shown to have a strong environmental component to its etiopathogenesis. However, work is still needed to identify and characterize environmental chemicals that could alter the expression and function of the nigrostriatal dopamine system. Of particular interest is the neurotoxicological effect of perfluorinated compounds, such as perfluorooctane sulfonate (PFOS), which has been demonstrated to alter aspects of dopamine signaling. Using in vitro approaches, we have elaborated these initial findings to demonstrate the neurotoxicity of PFOS to the SH-SY5Y neuroblastoma cell line and dopaminergic primary cultured neurons. Using an in vivo model, we did not observe a deficit to dopaminergic terminals in the striatum of mice exposed to 10 mg/kg PFOS for 14 days. However, subsequent exposure to the selective dopaminergic neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) significantly reduced the expression of dopamine transporter (DAT) and tyrosine hydroxylase (TH), and resulted in an even greater reduction in DAT expression in animals previously exposed to PFOS. These findings suggest that PFOS is neurotoxic to the nigrostriatal dopamine circuit and this neurotoxicity could prime the dopamine terminal to more extensive damage following additional toxicological insults.
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Affiliation(s)
- Rahul Patel
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
| | - Joshua M Bradner
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
- Center for Neurodegenerative Disease, School of Medicine, Emory University, Atlanta, GA 30322, USA.
| | - Kristen A Stout
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
- Center for Neurodegenerative Disease, School of Medicine, Emory University, Atlanta, GA 30322, USA.
| | - William Michael Caudle
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
- Center for Neurodegenerative Disease, School of Medicine, Emory University, Atlanta, GA 30322, USA.
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Lohr KM, Chen M, Hoffman CA, McDaniel MJ, Stout KA, Dunn AR, Wang M, Bernstein AI, Miller GW. Vesicular Monoamine Transporter 2 (VMAT2) Level Regulates MPTP Vulnerability and Clearance of Excess Dopamine in Mouse Striatal Terminals. Toxicol Sci 2016; 153:79-88. [PMID: 27287315 DOI: 10.1093/toxsci/kfw106] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The vesicular monoamine transporter 2 (VMAT2) packages neurotransmitters for release during neurotransmission and sequesters toxicants into vesicles to prevent neuronal damage. In mice, low VMAT2 levels causes catecholaminergic cell loss and behaviors resembling Parkinson's disease, while high levels of VMAT2 increase dopamine release and protect against dopaminergic toxicants. However, comparisons across these VMAT2 mouse genotypes were impossible due to the differing genetic background strains of the animals. Following back-crossing to a C57BL/6 line, we confirmed that mice with approximately 95% lower VMAT2 levels compared with wild-type (VMAT2-LO) display significantly reduced vesicular uptake, progressive dopaminergic terminal loss with aging, and exacerbated 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity. Conversely, VMAT2-overexpressing mice (VMAT2-HI) are protected from the loss of striatal terminals following MPTP treatment. We also provide evidence that enhanced vesicular filling in the VMAT2-HI mice modifies the handling of newly synthesized dopamine, indicated by changes in indirect measures of extracellular dopamine clearance. These results confirm the role of VMAT2 in the protection of vulnerable nigrostriatal dopamine neurons and may also provide new insight into the side effects of L-DOPA treatments in Parkinson's disease.
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Affiliation(s)
- Kelly M Lohr
- *Department of Environmental Health, Rollins School of Public Health
| | - Merry Chen
- *Department of Environmental Health, Rollins School of Public Health
| | - Carlie A Hoffman
- *Department of Environmental Health, Rollins School of Public Health
| | | | - Kristen A Stout
- *Department of Environmental Health, Rollins School of Public Health
| | - Amy R Dunn
- *Department of Environmental Health, Rollins School of Public Health
| | - Minzheng Wang
- *Department of Environmental Health, Rollins School of Public Health
| | | | - Gary W Miller
- *Department of Environmental Health, Rollins School of Public Health Center for Neurodegenerative Diseases Department of Pharmacology Department of Neurology, Emory University, Atlanta, Georgia, 30322
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Zeliger HI. Exposure to lipophilic chemicals as a cause of neurological impairments, neurodevelopmental disorders and neurodegenerative diseases. Interdiscip Toxicol 2013; 6:103-10. [PMID: 24678247 PMCID: PMC3967436 DOI: 10.2478/intox-2013-0018] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 09/25/2013] [Accepted: 09/30/2013] [Indexed: 11/26/2022] Open
Abstract
Many studies have associated environmental exposure to chemicals with neurological impairments (NIs) including neuropathies, cognitive, motor and sensory impairments; neurodevelopmental disorders (NDDs) including autism and attention deficit hyperactivity disorder (ADHD); neurodegenerative diseases (NDGs) including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis (ALS). The environmental chemicals shown to induce all these diseases include persistent organic pollutants (POPs), the plastic exudates bisphenol A and phthalates, low molecular weight hydrocarbons (LMWHCs) and polynuclear aromatic hydrocarbons (PAHs). It is reported here that though these chemicals differ widely in their chemical properties, reactivities and known points of attack in humans, a common link does exist between them. All are lipophilic species found in serum and they promote the sequential absorption of otherwise non-absorbed toxic hydrophilic species causing these diseases.
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Affiliation(s)
- Harold I Zeliger
- Zeliger Chemical, Toxicological, and Environmental Research, West Charlton, NY, USA
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Zeliger HI. Lipophilic chemical exposure as a cause of cardiovascular disease. Interdiscip Toxicol 2013; 6:55-62. [PMID: 24179429 PMCID: PMC3798856 DOI: 10.2478/intox-2013-0010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 06/18/2013] [Accepted: 06/24/2013] [Indexed: 01/06/2023] Open
Abstract
Environmental chemical exposure has been linked to numerous diseases in humans. These diseases include cancers; neurological and neurodegenerative diseases; metabolic disorders including type 2 diabetes, metabolic syndrome and obesity; reproductive and developmental disorders; and endocrine disorders. Many studies have associated the link between exposures to environmental chemicals and cardiovascular disease (CVD). These chemicals include persistent organic pollutants (POPs); the plastic exudates bisphenol A and phthalates; low molecular weight hydrocarbons (LMWHCs); and poly nuclear aromatic hydrocarbons (PAHs). Here it is reported that though the chemicals reported on differ widely in chemical properties and known points of attack in humans, a common link exists between them. All are lipophilic species that are found in serum. Environmentally induced CVD is related to total lipophilic chemical load in the blood. Lipophiles serve to promote the absorption of otherwise not absorbed toxic hydrophilic species that promote CVD.
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Affiliation(s)
- Harold I Zeliger
- Zeliger Chemical, Toxicological and Environmental Research, West Charlton, New York, USA
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