1
|
Goldman SM, Weaver FM, Gonzalez B, Stroupe KT, Cao L, Colletta K, Brown EG, Tanner CM. Parkinson's Disease Progression and Exposure to Contaminated Water at Camp Lejeune. Mov Disord 2024. [PMID: 38988230 DOI: 10.1002/mds.29922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 06/16/2024] [Accepted: 06/24/2024] [Indexed: 07/12/2024] Open
Abstract
BACKGROUND We recently reported an increased risk of Parkinson's disease (PD) in service members who resided at Marine Base Camp Lejeune, North Carolina, when water supplies were contaminated with trichloroethylene and other volatile organic compounds (VOCs). Prior studies suggest that environmental exposures may affect PD phenotype or progression, but this has not been reported for VOCs. OBJECTIVE The objective of this study was to test whether PD progression is faster in individuals exposed to VOCs in water at Camp Lejeune. METHODS A cohort of 172,128 marines residing at Camp Lejeune between 1975 and 1985 was previously assembled. We identified individuals with PD in Veterans Health Administration and Medicare databases between 2000 and 2021. Using estimates derived by the US Agency for Toxic Substances and Disease Registry, we classified individuals as exposed or unexposed to VOCs in residential water. We used Kaplan-Meier and Cox regression models to test differences between exposed and unexposed groups in the time from PD diagnosis until psychosis, fracture, fall, or death. RESULTS Among 270 persons with PD, 177 (65.6%) were exposed to VOCs in residential water. Median cumulative exposure was 4970 μg/L-months, >50-fold the permissible level. Time until psychosis, fracture, and fall were all shorter in the exposed group, with adjusted hazard ratios (HRs) exceeding 2: psychosis HR, 2.19 (95% confidence interval [CI]: 0.99-4.83); fracture HR, 2.44 (95% CI: 0.91-6.55); and fall HR, 2.64 (95% CI: 0.97-7.21). A significant dose response was observed for time to fall (P trend, 0.032). No differences were observed for time until death. CONCLUSIONS PD progression may be faster in persons exposed to trichloroethylene and other VOCs in water decades earlier. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
Collapse
Affiliation(s)
- Samuel M Goldman
- Division of Occupational, Environmental, and Climate Medicine, University of California San Francisco, San Francisco, California, USA
- Research Service, San Francisco Veterans Affairs Health Care System, San Francisco, California, USA
| | - Frances M Weaver
- Center of Innovation for Complex Chronic Healthcare, Hines Veterans Administration Hospital, Hines, Illinois, USA
- Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, Illinois, USA
| | - Beverly Gonzalez
- Geriatrics and Extended Care Data Analysis Center, Canandaigua VA Medical Center, Canandaigua, New York, USA
| | - Kevin T Stroupe
- Center of Innovation for Complex Chronic Healthcare, Hines Veterans Administration Hospital, Hines, Illinois, USA
- Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, Illinois, USA
| | - Lishan Cao
- Center of Innovation for Complex Chronic Healthcare, Hines Veterans Administration Hospital, Hines, Illinois, USA
| | - Kalea Colletta
- Movement Disorder Section, Hines Veterans Administration Hospital, Hines, Illinois, USA
| | - Ethan G Brown
- Research Service, San Francisco Veterans Affairs Health Care System, San Francisco, California, USA
- Geriatrics and Extended Care Data Analysis Center, Canandaigua VA Medical Center, Canandaigua, New York, USA
| | - Caroline M Tanner
- Research Service, San Francisco Veterans Affairs Health Care System, San Francisco, California, USA
- Geriatrics and Extended Care Data Analysis Center, Canandaigua VA Medical Center, Canandaigua, New York, USA
| |
Collapse
|
2
|
Dorsey ER, Kinel D, Pawlik ME, Zafar M, Lettenberger SE, Coffey M, Auinger P, Hylton KL, Shaw CW, Adams JL, Barbano R, Braun MK, Schwarz HB, Lawrence BP, Kieburtz K, Tanner CM, de Miranda BR, Goldman SM. Dry-Cleaning Chemicals and a Cluster of Parkinson's Disease and Cancer: A Retrospective Investigation. Mov Disord 2024; 39:606-613. [PMID: 38389433 DOI: 10.1002/mds.29723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 12/20/2023] [Accepted: 01/08/2024] [Indexed: 02/24/2024] Open
Abstract
BACKGROUND Environmental exposure to trichloroethylene (TCE), a carcinogenic dry-cleaning chemical, may be linked to Parkinson's disease (PD). OBJECTIVE The objective of this study was to determine whether PD and cancer were elevated among attorneys who worked near a contaminated site. METHODS We surveyed and evaluated attorneys with possible exposure and assessed a comparison group. RESULTS Seventy-nine of 82 attorneys (96.3%; mean [SD] age: 69.5 [11.4] years; 89.9% men) completed at least one phase of the study. For comparison, 75 lawyers (64.9 [10.2] years; 65.3% men) underwent clinical evaluations. Four (5.1%) of them who worked near the polluted site reported PD, more than expected based on age and sex (1.7%; P = 0.01) but not significantly higher than the comparison group (n = 1 [1.3%]; P = 0.37). Fifteen (19.0%), compared to four in the comparison group (5.3%; P = 0.049), had a TCE-related cancer. CONCLUSIONS In a retrospective study, diagnoses of PD and TCE-related cancers appeared to be elevated among attorneys who worked next to a contaminated dry-cleaning site. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
Collapse
Affiliation(s)
- E Ray Dorsey
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
- Center for Health & Technology, University of Rochester Medical Center, Rochester, New York, USA
| | - Dan Kinel
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
- Center for Health & Technology, University of Rochester Medical Center, Rochester, New York, USA
| | - Meghan E Pawlik
- Center for Health & Technology, University of Rochester Medical Center, Rochester, New York, USA
| | - Maryam Zafar
- Center for Health & Technology, University of Rochester Medical Center, Rochester, New York, USA
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Samantha E Lettenberger
- Center for Health & Technology, University of Rochester Medical Center, Rochester, New York, USA
| | - Madeleine Coffey
- Donald and Barbara Zucker School of Medicine, Uniondale, New York, USA
| | - Peggy Auinger
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
- Center for Health & Technology, University of Rochester Medical Center, Rochester, New York, USA
| | - Kevin L Hylton
- Kevin Hylton Environmental Services, Inc., Rochester, New York, USA
| | - Carol W Shaw
- Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, New York, USA
| | - Jamie L Adams
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
- Center for Health & Technology, University of Rochester Medical Center, Rochester, New York, USA
| | - Richard Barbano
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - Melanie K Braun
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - Heidi B Schwarz
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - B Paige Lawrence
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, New York, USA
| | - Karl Kieburtz
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
- Center for Health & Technology, University of Rochester Medical Center, Rochester, New York, USA
| | - Caroline M Tanner
- Department of Neurology, UCSF Health, San Francisco, California, USA
| | - Briana R de Miranda
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Samuel M Goldman
- Division of Occupational, Environmental, and Climate Medicine, University of California San Francisco, San Francisco, California, USA
| |
Collapse
|
3
|
Dorsey ER, Bloem BR. Parkinson's Disease Is Predominantly an Environmental Disease. JOURNAL OF PARKINSON'S DISEASE 2024; 14:451-465. [PMID: 38217613 PMCID: PMC11091623 DOI: 10.3233/jpd-230357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/04/2023] [Indexed: 01/15/2024]
Abstract
Parkinson's disease is the world's fastest growing brain disorder, and exposure to environmental toxicants is the principal reason. In this paper, we consider alternative, but unsatisfactory, explanations for its rise, including improved diagnostic skills, aging populations, and genetic causes. We then detail three environmental toxicants that are likely among the main causes of Parkinson's disease- certain pesticides, the solvent trichloroethylene, and air pollution. All three environmental toxicants are ubiquitous, many affect mitochondrial functioning, and all can access humans via various routes, including inhalation and ingestion. We reach the hopeful conclusion that most of Parkinson's disease is thus preventable and that we can help to create a world where Parkinson's disease is increasingly rare.
Collapse
Affiliation(s)
- E. Ray Dorsey
- Center for Health + Technology and Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Bastiaan R. Bloem
- Department of Neurology, Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behavior, Centre of Expertise for Parkinson and Movement Disorders, Nijmegen, the Netherlands
| |
Collapse
|
4
|
Śmiłowska K, Pietrzykowski T, Owczarek AJ, Dorsey ER, Bloem BR, van Wamelen DJ. The Prevalence of Parkinson's Disease in Poland: Regional and Sex-Related Differences. JOURNAL OF PARKINSON'S DISEASE 2024; 14:521-532. [PMID: 38457147 DOI: 10.3233/jpd-230291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Background Given the growing evidence for an environmental contribution to the etiology of Parkinson's disease (PD), searching for local and regional differences in PD prevalence in multiple areas across the world may further clarify the role of environmental toxins. Objective To provide local and regional prevalence estimates of PD in Poland. Methods We analyzed the prevalence of PD and its trend over the last decade (2010 to 2019) based on data from the National Health Fund in Poland. We specifically examined sex differences in PD prevalence, as well as differences across Polish regions. Results During the above period, the prevalence of PD in Poland increased from 226 per 100,000 to 269 per 100,000 inhabitants. Unexpectedly, we found that PD was 1.2-times more common in women than men. The increase in prevalence over the past decade was different between both sexes: an increase from 250 to 283 per 100,000 for women (13.3% increase), and from 200 to 254 per 100,000 for men (27.1% increase). In addition, we observed differences in prevalence across different Polish regions, with some regions having up to 51% lower prevalence rates than others. Conclusions The prevalence of PD in Poland is in line with previously reported prevalence rates across Europe. However, unlike the situation in most of the world, PD was more prevalent in women than men. We discuss several possible explanations as well as potential measures that might help to reduce the growth of PD.
Collapse
Affiliation(s)
- Katarzyna Śmiłowska
- Department of Neurology, 5th Regional Hospital in Sosnowiec, Poland
- Department of Neurology Centre of Expertise for Parkinson and Movement Disorders, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Tomasz Pietrzykowski
- Faculty of Law and Administration, Research Centre for Public Policy and Regulatory Governance, University of Silesia in Katowice, Katowice, Poland
| | - Aleksander J Owczarek
- Department of Pathophysiology, Health Promotion and Obesity Management Unit,Medical University of Silesia, Katowice, Poland
| | - E Ray Dorsey
- Center for Health + Technology, University of Rochester Medical Center, Rochester, NY, USA
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Bastiaan R Bloem
- Department of Neurology Centre of Expertise for Parkinson and Movement Disorders, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Daniel J van Wamelen
- Department of Neurology Centre of Expertise for Parkinson and Movement Disorders, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
- Department of Neuroimaging, Institute of Psychiatry and Neuroscience, King's College London, London, UK
- Parkinson's Foundation Center of Excellence, King's College Hospital, Denmark Hill, London, UK
| |
Collapse
|
5
|
Dorsey ER, De Miranda BR, Horsager J, Borghammer P. The Body, the Brain, the Environment, and Parkinson's Disease. JOURNAL OF PARKINSON'S DISEASE 2024; 14:363-381. [PMID: 38607765 DOI: 10.3233/jpd-240019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2024]
Abstract
The brain- and body-first models of Lewy body disorders predict that aggregated alpha-synuclein pathology usually begins in either the olfactory system or the enteric nervous system. In both scenarios the pathology seems to arise in structures that are closely connected to the outside world. Environmental toxicants, including certain pesticides, industrial chemicals, and air pollution are therefore plausible trigger mechanisms for Parkinson's disease and dementia with Lewy bodies. Here, we propose that toxicants inhaled through the nose can lead to pathological changes in alpha-synuclein in the olfactory system that subsequently spread and give rise to a brain-first subtype of Lewy body disease. Similarly, ingested toxicants can pass through the gut and cause alpha-synuclein pathology that then extends via parasympathetic and sympathetic pathways to ultimately produce a body-first subtype. The resulting spread can be tracked by the development of symptoms, clinical assessments, in vivo imaging, and ultimately pathological examination. The integration of environmental exposures into the brain-first and body-first models generates testable hypotheses, including on the prevalence of the clinical conditions, their future incidence, imaging patterns, and pathological signatures. The proposed link, though, has limitations and leaves many questions unanswered, such as the role of the skin, the influence of the microbiome, and the effects of ongoing exposures. Despite these limitations, the interaction of exogenous factors with the nose and the gut may explain many of the mysteries of Parkinson's disease and open the door toward the ultimate goal -prevention.
Collapse
Affiliation(s)
- E Ray Dorsey
- Department of Neurology and Center for Health and Technology, University of Rochester Medical Center, Rochester, NY, USA
| | - Briana R De Miranda
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jacob Horsager
- Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark
| | - Per Borghammer
- Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark
| |
Collapse
|
6
|
Adamson A, Ilieva N, Stone WJ, De Miranda BR. Low-dose inhalation exposure to trichloroethylene induces dopaminergic neurodegeneration in rodents. Toxicol Sci 2023; 196:218-228. [PMID: 37669148 DOI: 10.1093/toxsci/kfad090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023] Open
Abstract
Trichloroethylene (TCE) is one of the most pervasive environmental contaminants in the world and is associated with Parkinson disease (PD) risk. Experimental models in rodents show that TCE is selectively toxic to dopaminergic neurons at high doses of ingestion, however, TCE is a highly volatile toxicant, and the primary pathway of human exposure is inhalation. As TCE is a highly lipophilic, volatile organic compound (VOC), inhalation exposure results in rapid diffusion throughout the brain, avoiding first-pass hepatic metabolism that necessitated high doses to recapitulate exposure conditions observed in human populations. We hypothesized that inhalation of TCE would induce significantly more potent neurodegeneration than ingestion and better recapitulate environmental conditions of vapor intrusion or off gassing from liquid TCE. To this end, we developed a novel, whole-body passive exposure inhalation chamber in which we exposed 10-month-old male and female Lewis rats to 50 ppm TCE (time weighted average, TWA) or filtered room air (control) over 8 weeks. In addition, we exposed 12-month-old male and female C57Bl/6 mice to 100 ppm TCE (TWA) or control over 12 weeks. Both rats and mice exposed to chronic TCE inhalation showed significant degeneration of nigrostriatal dopaminergic neurons as well as motor and gait impairments. TCE exposure also induced accumulation of pSer129-αSyn in dopaminergic neurons as well as microglial activation within the substantia nigra of rats. Collectively, these data indicate that TCE inhalation causes highly potent dopaminergic neurodegeneration and recapitulates some of the observed neuropathology associated with PD, providing a future platform for insight into the mechanisms and environmental conditions that influence PD risk from TCE exposure.
Collapse
Affiliation(s)
- Ashley Adamson
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, The University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Neda Ilieva
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, The University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - William J Stone
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, The University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Briana R De Miranda
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, The University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| |
Collapse
|
7
|
Adamson AB, Ilieva NM, Stone WJ, De Miranda BR. Low-dose inhalation exposure to trichloroethylene induces dopaminergic neurodegeneration in rodents. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548754. [PMID: 37502893 PMCID: PMC10369984 DOI: 10.1101/2023.07.12.548754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Trichloroethylene (TCE) is one of the most pervasive environmental contaminants in the world and is associated with Parkinson disease (PD) risk. Experimental models in rodents show that TCE is selectively toxic to dopaminergic neurons at high doses of ingestion, however, TCE is a highly volatile toxicant, and the primary pathway of human exposure is inhalation. As TCE is a highly lipophilic, volatile organic contaminant (VOC), inhalation exposure results in rapid diffusion throughout the brain, avoiding first-pass hepatic metabolism that necessitated high doses to recapitulate exposure conditions observed in human populations. We hypothesized that inhalation of TCE would induce significantly more potent neurodegeneration than ingestion and better recapitulate environmental conditions of vapor intrusion or off gassing from liquid TCE. To this end, we developed a novel, whole-body passive exposure inhalation chamber in which we exposed 10-month-old male and female Lewis rats to 50 ppm TCE (time weighted average, TWA) or filtered room air (control) over 8 weeks. In addition, we exposed 12-month-old male and female C57Bl/6 mice to 100 ppm TCE (TWA) or control over 12 weeks. Both rats and mice exposed to chronic TCE inhalation showed significant degeneration of nigrostriatal dopaminergic neurons as well as motor and gait impairments. TCE exposure also induced accumulation of pSer129-αSyn in dopaminergic neurons as well as microglial activation within the substantia nigra of rats. Collectively, these data indicate that TCE inhalation causes highly potent dopaminergic neurodegeneration and recapitulates some of the observed neuropathology associated with PD, providing a future platform for insight into the mechanisms and environmental conditions that influence PD risk from TCE exposure.
Collapse
|
8
|
Goldman SM, Weaver FM, Stroupe KT, Cao L, Gonzalez B, Colletta K, Brown EG, Tanner CM. Risk of Parkinson Disease Among Service Members at Marine Corps Base Camp Lejeune. JAMA Neurol 2023; 80:673-681. [PMID: 37184848 PMCID: PMC10186205 DOI: 10.1001/jamaneurol.2023.1168] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 03/03/2023] [Indexed: 05/16/2023]
Abstract
Importance An increased risk of Parkinson disease (PD) has been associated with exposure to the solvent trichloroethylene (TCE), but data are limited. Millions of people in the US and worldwide are exposed to TCE in air, food, and water. Objective To test whether the risk of PD is higher in veterans who served at Marine Corps Base Camp Lejeune, whose water supply was contaminated with TCE and other volatile organic compounds (VOCs), compared with veterans who did not serve on that base. Design, Setting, and Participants This population-based cohort study examined the risk for PD among all Marines and Navy personnel who resided at Camp Lejeune, North Carolina (contaminated water) (n = 172 128), or Camp Pendleton, California (uncontaminated water) (n = 168 361), for at least 3 months between 1975 and 1985, with follow-up from January 1, 1997, until February 17, 2021. Veterans Health Administration and Medicare databases were searched for International Classification of Diseases diagnostic codes for PD or other forms of parkinsonism and related medications and for diagnostic codes indicative of prodromal disease. Parkinson disease diagnoses were confirmed by medical record review. Exposures Water supplies at Camp Lejeune were contaminated with several VOCs. Levels were highest for TCE, with monthly median values greater than 70-fold the permissible amount. Main Outcome and Measures Risk of PD in former residents of Camp Lejeune relative to residents of Camp Pendleton. In those without PD or another form of parkinsonism, the risk of being diagnosed with features of prodromal PD were assessed individually and cumulatively using likelihood ratio tests. Results Health data were available for 158 122 veterans (46.4%). Demographic characteristics were similar between Camp Lejeune (5.3% women, 94.7% men; mean [SD] attained age of 59.64 [4.43] years; 29.7% Black, 6.0% Hispanic, 67.6% White; and 2.7% other race and ethnicity) and Camp Pendleton (3.8% women, 96.2% men; mean [SD] age, 59.80 [4.62] years; 23.4% Black, 9.4% Hispanic, 71.1% White, and 5.5% other race and ethnicity). A total of 430 veterans had PD, with 279 from Camp Lejeune (prevalence, 0.33%) and 151 from Camp Pendleton (prevalence, 0.21%). In multivariable models, Camp Lejeune veterans had a 70% higher risk of PD (odds ratio, 1.70; 95% CI, 1.39-2.07; P < .001). No excess risk was found for other forms of neurodegenerative parkinsonism. Camp Lejeune veterans also had a significantly increased risk of prodromal PD diagnoses, including tremor, anxiety, and erectile dysfunction, and higher cumulative prodromal risk scores. Conclusions and Relevance The study's findings suggest that the risk of PD is higher in persons exposed to TCE and other VOCs in water 4 decades ago. Millions worldwide have been and continue to be exposed to this ubiquitous environmental contaminant.
Collapse
Affiliation(s)
- Samuel M. Goldman
- Division of Occupational and Environmental Medicine, University of California, San Francisco
- San Francisco Veterans Affairs Health Care System, San Francisco, California
| | - Frances M. Weaver
- Center of Innovation for Complex Chronic Healthcare, Hines Veterans Affairs Hospital, Hines, Illinois
- Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, Illinois
| | - Kevin T. Stroupe
- Center of Innovation for Complex Chronic Healthcare, Hines Veterans Affairs Hospital, Hines, Illinois
- Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, Illinois
| | - Lishan Cao
- Center of Innovation for Complex Chronic Healthcare, Hines Veterans Affairs Hospital, Hines, Illinois
| | - Beverly Gonzalez
- Center of Innovation for Complex Chronic Healthcare, Hines Veterans Affairs Hospital, Hines, Illinois
| | - Kalea Colletta
- Center of Innovation for Complex Chronic Healthcare, Hines Veterans Affairs Hospital, Hines, Illinois
| | - Ethan G. Brown
- San Francisco Veterans Affairs Health Care System, San Francisco, California
- Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco
| | - Caroline M. Tanner
- San Francisco Veterans Affairs Health Care System, San Francisco, California
- Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco
| |
Collapse
|
9
|
Dorsey ER, Zafar M, Lettenberger SE, Pawlik ME, Kinel D, Frissen M, Schneider RB, Kieburtz K, Tanner CM, De Miranda BR, Goldman SM, Bloem BR. Trichloroethylene: An Invisible Cause of Parkinson's Disease? JOURNAL OF PARKINSON'S DISEASE 2023; 13:203-218. [PMID: 36938742 PMCID: PMC10041423 DOI: 10.3233/jpd-225047] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
The etiologies of Parkinson's disease (PD) remain unclear. Some, such as certain genetic mutations and head trauma, are widely known or easily identified. However, these causes or risk factors do not account for the majority of cases. Other, less visible factors must be at play. Among these is a widely used industrial solvent and common environmental contaminant little recognized for its likely role in PD: trichloroethylene (TCE). TCE is a simple, six-atom molecule that can decaffeinate coffee, degrease metal parts, and dry clean clothes. The colorless chemical was first linked to parkinsonism in 1969. Since then, four case studies involving eight individuals have linked occupational exposure to TCE to PD. In addition, a small epidemiological study found that occupational or hobby exposure to the solvent was associated with a 500% increased risk of developing PD. In multiple animal studies, the chemical reproduces the pathological features of PD.Exposure is not confined to those who work with the chemical. TCE pollutes outdoor air, taints groundwater, and contaminates indoor air. The molecule, like radon, evaporates from underlying soil and groundwater and enters homes, workplaces, or schools, often undetected. Despite widespread contamination and increasing industrial, commercial, and military use, clinical investigations of TCE and PD have been limited. Here, through a literature review and seven illustrative cases, we postulate that this ubiquitous chemical is contributing to the global rise of PD and that TCE is one of its invisible and highly preventable causes. Further research is now necessary to examine this hypothesis.
Collapse
Affiliation(s)
- E Ray Dorsey
- Center for Health + Technology, University of Rochester Medical Center, Rochester, NY, USA
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Maryam Zafar
- Center for Health + Technology, University of Rochester Medical Center, Rochester, NY, USA
| | | | - Meghan E Pawlik
- Center for Health + Technology, University of Rochester Medical Center, Rochester, NY, USA
| | - Dan Kinel
- Center for Health + Technology, University of Rochester Medical Center, Rochester, NY, USA
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Myrthe Frissen
- Radboud University Medical Centre; Donders Institute for Brain, Cognition and Behaviour; Department of Neurology; Centre of Expertise for Parkinson & Movement Disorders; Nijmegen, the Netherlands
| | - Ruth B Schneider
- Center for Health + Technology, University of Rochester Medical Center, Rochester, NY, USA
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Karl Kieburtz
- Center for Health + Technology, University of Rochester Medical Center, Rochester, NY, USA
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Caroline M Tanner
- Weill Institute for Neurosciences, Department of Neurology, University of California-San Francisco, San Francisco, CA, USA
| | - Briana R De Miranda
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Samuel M Goldman
- Division of Occupational and Environmental Medicine, San Francisco Veterans Affairs Health Care System, School of Medicine, University of California-San Francisco, San Francisco, CA, USA
| | - Bastiaan R Bloem
- Radboud University Medical Centre; Donders Institute for Brain, Cognition and Behaviour; Department of Neurology; Centre of Expertise for Parkinson & Movement Disorders; Nijmegen, the Netherlands
| |
Collapse
|
10
|
Brahadeeswaran S, Lateef M, Calivarathan L. An Insight into the Molecular Mechanism of Mitochondrial Toxicant-induced Neuronal Apoptosis in Parkinson's Disease. Curr Mol Med 2023; 23:63-75. [PMID: 35125081 DOI: 10.2174/1566524022666220203163631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 11/25/2021] [Accepted: 12/07/2021] [Indexed: 12/16/2022]
Abstract
Parkinson's disease (PD) is one of the most common progressive neurodegenerative disorders affecting approximately 1% of the world's population at the age of 50 and above. Majority of PD cases are sporadic and show symptoms after the age of 60 and above. At that time, most of the dopaminergic neurons in the region of substantia nigra pars compacta have been degenerated. Although in past decades, discoveries of genetic mutations linked to PD have significantly impacted our current understanding of the pathogenesis of this devastating disorder, it is likely that the environment also plays a critical role in the etiology of sporadic PD. Recent epidemiological and experimental studies indicate that exposure to environmental agents, including a number of agricultural and industrial chemicals, may contribute to the pathogenesis of several neurodegenerative disorders, including PD. Furthermore, there is a strong correlation between mitochondrial dysfunction and several forms of neurodegenerative disorders, including Alzheimer's disease (AD), Huntington's disease (HD), Amyotrophic lateral sclerosis (ALS) and PD. Interestingly, substantia nigra of patients with PD has been shown to have a mild deficiency in mitochondrial respiratory electron transport chain NADH dehydrogenase (Complex I) activity. This review discusses the role of mitochondrial toxicants in the selective degeneration of dopaminergic neurons targeting the electron transport system that leads to Parkinsonism.
Collapse
Affiliation(s)
- Subhashini Brahadeeswaran
- Molecular Pharmacology & Toxicology Laboratory, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Neelakudi Campus, Thiruvarur - 610005, India
| | - Mohammad Lateef
- Department of Animal Sciences, School of Life Sciences, Central University of Kashmir, Nunar Campus, Ganderbal - 191201, Jammu & Kashmir, India
| | - Latchoumycandane Calivarathan
- Molecular Pharmacology & Toxicology Laboratory, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Neelakudi Campus, Thiruvarur - 610005, India
| |
Collapse
|
11
|
Epigenome-Wide Analysis of DNA Methylation in Parkinson's Disease Cortex. Life (Basel) 2022; 12:life12040502. [PMID: 35454993 PMCID: PMC9025601 DOI: 10.3390/life12040502] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/21/2022] [Accepted: 02/24/2022] [Indexed: 12/27/2022] Open
Abstract
Background: Epigenetic factors including DNA methylation contribute to specific patterns of gene expression. Gene−environment interactions can change the methylation status in the brain, and accumulation of these epigenetic changes over a lifespan may be co-responsible for a neurodegenerative disease like Parkinson’s disease, which that is characterised by a late onset in life. Aims: To determine epigenetic modifications in the brains of Parkinson’s disease patients. Patients and Methods: DNA methylation patterns were compared in the cortex tissue of 14 male PD patients and 10 male healthy individuals using the Illumina Methylation 450 K chip. Subsequently, DNA methylation of candidate genes was evaluated using bisulphite pyrosequencing, and DNA methylation of cytochrome P450 2E1 (CYP2E1) was characterized in DNA from blood mononuclear cells (259 PD patients and 182 healthy controls) and skin fibroblasts (10 PD patients and 5 healthy controls). Protein levels of CYP2E1 were analysed using Western blot in human cortex and knock-out mice brain samples. Results: We found 35 hypomethylated and 22 hypermethylated genes with a methylation M-value difference >0.5. Decreased methylation of cytochrome P450 2E1 (CYP2E1) was associated with increased protein levels in PD brains, but in peripheral tissues, i.e., in blood cells and skin fibroblasts, DNA methylation of CYP2E1 was unchanged. In CYP2E1 knock-out mice brain alpha-synuclein (SNCA) protein levels were down-regulated compared to wild-type mice, whereas treatment with trichloroethylene (TCE) up-regulated CYP2E1 protein in a dose-dependent manner in cultured cells. We further identified an interconnected group of genes associated with oxidative stress, such as Methionine sulfoxide reductase A (MSRA) and tumour protein 73 (TP73) in the brain, which again were not paralleled in other tissues and appeared to indicate brain-specific changes. Conclusions: Our study revealed surprisingly few dysmethylated genes in a brain region less affected in PD. We confirmed hypomethylation of CYP2E1.
Collapse
|
12
|
Environmental triggers of Parkinson's disease - Implications of the Braak and dual-hit hypotheses. Neurobiol Dis 2021; 163:105601. [PMID: 34954321 DOI: 10.1016/j.nbd.2021.105601] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/05/2021] [Accepted: 12/22/2021] [Indexed: 11/22/2022] Open
Abstract
Idiopathic Parkinson's disease (PD) may take decades to develop, during which many risk or protective factors may come into play to initiate the pathogenesis or modify its progression to clinical PD. The lack of understanding of this prodromal phase of PD and the factors involved has been a major hurdle in the study of PD etiology and preventive strategies. Although still controversial, the Braak and dual-hit hypotheses that PD may start peripherally in the olfactory structures and/or the gut provides a theoretical platform to identify the triggers and modifiers of PD prodromal development and progression. This is particularly true for the search of environmental causes of PD as the olfactory structures and gut are the major human mucosal interfaces with the environment. In this review, we lay out our personal views about how the Braak and dual-hit hypotheses may help us search for the environmental triggers and modifiers for PD, summarize available experimental and epidemiological evidence, and discuss research gaps and strategies.
Collapse
|
13
|
Shin EJ, Jeong JH, Hwang Y, Sharma N, Dang DK, Nguyen BT, Nah SY, Jang CG, Bing G, Nabeshima T, Kim HC. Methamphetamine-induced dopaminergic neurotoxicity as a model of Parkinson's disease. Arch Pharm Res 2021; 44:668-688. [PMID: 34286473 DOI: 10.1007/s12272-021-01341-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 07/06/2021] [Indexed: 12/01/2022]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disease with a high prevalence, approximately 1 % in the elderly population. Numerous studies have demonstrated that methamphetamine (MA) intoxication caused the neurological deficits and nigrostriatal damage seen in Parkinsonian conditions, and subsequent rodent studies have found that neurotoxic binge administration of MA reproduced PD-like features, in terms of its symptomatology and pathology. Several anti-Parkinsonian medications have been shown to attenuate the motor impairments and dopaminergic damage induced by MA. In addition, it has been recognized that mitochondrial dysfunction, oxidative stress, pro-apoptosis, proteasomal/autophagic impairment, and neuroinflammation play important roles in inducing MA neurotoxicity. Importantly, MA neurotoxicity has been shown to share a common mechanism of dopaminergic toxicity with that of PD pathogenesis. This review describes the major findings on the neuropathological features and underlying neurotoxic mechanisms induced by MA and compares them with Parkinsonian pathogenesis. Taken together, it is suggested that neurotoxic binge-type administration of MA in rodents is a valid animal model for PD that may provide knowledge on the neuropathogenesis of PD.
Collapse
Affiliation(s)
- Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea
| | - Ji Hoon Jeong
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, College of Medicine, Chung-Ang University, 06974, Seoul, Republic of Korea
| | - Yeonggwang Hwang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea
| | - Naveen Sharma
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea.,Department of Global Innovative Drugs, Graduate School of Chung-Ang University, College of Medicine, Chung-Ang University, 06974, Seoul, Republic of Korea
| | - Duy-Khanh Dang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea.,Pharmacy Faculty, Can Tho University of Medicine and Pharmacy, 900000, Can Tho City, Vietnam
| | - Bao-Trong Nguyen
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory, Department of Physiology, College of Veterinary Medicine and Bio/Molecular Informatics Center, Konkuk University, 05029, Seoul, Republic of Korea
| | - Choon-Gon Jang
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 16419, Suwon, Republic of Korea
| | - Guoying Bing
- Department of Neuroscience, College of Medicine, University of Kentucky, KY, 40536, Lexington, USA
| | - Toshitaka Nabeshima
- Advanced Diagnostic System Research Laboratory, Graduate School of Health Science, Fujita Health University, 470-1192, Toyoake, Japan
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea. .,Neuropsychopharmacology & Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea.
| |
Collapse
|
14
|
Nielsen SS, Warden MN, Sallmén M, Sainio M, Uuksulainen S, Checkoway H, Hublin C, Racette BA. Solvent exposed occupations and risk of Parkinson disease in Finland. Clin Park Relat Disord 2021; 4:100092. [PMID: 34316670 PMCID: PMC8299961 DOI: 10.1016/j.prdoa.2021.100092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 03/06/2021] [Accepted: 03/25/2021] [Indexed: 12/01/2022] Open
Abstract
Finnish register-based case-control Parkinson disease (PD) studies are feasible. Some occupations with potential for exposure to solvents are associated with PD. Chlorinated hydrocarbon solvents in particular might increase PD risk modestly. Some occupational co-exposures might enhance PD-solvent associations in PD studies. Studies without smoking/education data will underestimate PD-solvent associations.
Introduction Epidemiologic and toxicology studies suggest that exposure to various solvents, especially chlorinated hydrocarbon solvents, might increase Parkinson disease (PD) risk. Methods In a population-based case-control study in Finland, we examined whether occupations with potential for solvent exposures were associated with PD. We identified newly diagnosed cases age 45–84 from a nationwide medication reimbursement register in 1995–2014. From the population register, we randomly selected non-PD controls matched on sex, along with birth and diagnosis years (age). We included 11,757 cases and 23,236 controls with an occupation in the 1990 census, corresponding to age 40–60. We focused on 28 occupations with ≥ 5% probability of solvent exposure according to the Finnish Job Exposure Matrix. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) by logistic regression modeling, adjusting for age, sex, socioeconomic status, and smoking probability. Results Similar proportions of cases (5.5%) and controls (5.6%) had an occupation with potential exposure to any solvents. However, all occupations with a point estimate above one, and all significantly or marginally significantly associated with PD (electronic/telecommunications worker [OR = 1.63, 95% CI 1.05–2.50], laboratory assistant [OR = 1.40, 95% CI 0.98–1.99], and machine/engine mechanic [OR = 1.23, 95% CI 0.99–1.52]) entailed potential for exposure to chlorinated hydrocarbon solvents, specifically. Secondary analyses indicated exposure to polycyclic aromatic hydrocarbons and some metals might contribute to the association for mechanics. Conclusion PD risk might be slightly increased in occupations with potential exposure to chlorinated hydrocarbon solvents. Confirmation is required in additional studies that adjust for other occupational exposures and smoking.
Collapse
Affiliation(s)
- Susan Searles Nielsen
- Washington University School of Medicine in St. Louis, Department of Neurology, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Mark N Warden
- Washington University School of Medicine in St. Louis, Department of Neurology, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Markku Sallmén
- Finnish Institute of Occupational Health, PO Box 18, FI-00032 Tyoterveyslaitos, Arinatie 3 A, 00370 Helsinki, Finland
| | - Markku Sainio
- Finnish Institute of Occupational Health, PO Box 18, FI-00032 Tyoterveyslaitos, Arinatie 3 A, 00370 Helsinki, Finland
| | - Sanni Uuksulainen
- Finnish Institute of Occupational Health, PO Box 18, FI-00032 Tyoterveyslaitos, Arinatie 3 A, 00370 Helsinki, Finland
| | - Harvey Checkoway
- University of California, San Diego, Herbert Wertheim School of Public Health, 9500 Gilman Drive, La Jolla, CA 92093, USA.,University of California, San Diego, Department of Neurosciences, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Christer Hublin
- Finnish Institute of Occupational Health, PO Box 18, FI-00032 Tyoterveyslaitos, Arinatie 3 A, 00370 Helsinki, Finland
| | - Brad A Racette
- Washington University School of Medicine in St. Louis, Department of Neurology, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.,University of the Witwatersrand, School of Public Health, Faculty of Health Sciences, 27 St. Andrews Road, Parktown, Johannesburg, 2193, South Africa
| |
Collapse
|
15
|
El-Gamal M, Salama M, Collins-Praino LE, Baetu I, Fathalla AM, Soliman AM, Mohamed W, Moustafa AA. Neurotoxin-Induced Rodent Models of Parkinson's Disease: Benefits and Drawbacks. Neurotox Res 2021; 39:897-923. [PMID: 33765237 DOI: 10.1007/s12640-021-00356-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 03/13/2021] [Accepted: 03/18/2021] [Indexed: 12/21/2022]
Abstract
Parkinson's disease (PD), the second most common neurodegenerative disorder, is characterized by cardinal motor impairments, including akinesia and tremor, as well as by a host of non-motor symptoms, including both autonomic and cognitive dysfunction. PD is associated with a death of nigral dopaminergic neurons, as well as the pathological spread of Lewy bodies, consisting predominantly of the misfolded protein alpha-synuclein. To date, only symptomatic treatments, such as levodopa, are available, and trials aiming to cure the disease, or at least halt its progression, have not been successful. Wong et al. (2019) suggested that the lack of effective therapy against neurodegeneration in PD might be attributed to the fact that the molecular mechanisms standing behind the dopaminergic neuronal vulnerability are still a major scientific challenge. Understanding these molecular mechanisms is critical for developing effective therapy. Thirty-five years ago, Calne and William Langston (1983) raised the question of whether biological or environmental factors precipitate the development of PD. In spite of great advances in technology and medicine, this question still lacks a clear answer. Only 5-15% of PD cases are attributed to a genetic mutation, with the majority of cases classified as idiopathic, which could be linked to exposure to environmental contaminants. Rodent models play a crucial role in understanding the risk factors and pathogenesis of PD. Additionally, well-validated rodent models are critical for driving the preclinical development of clinically translatable treatment options. In this review, we discuss the mechanisms, similarities and differences, as well as advantages and limitations of different neurotoxin-induced rat models of PD. In the second part of this review, we will discuss the potential future of neurotoxin-induced models of PD. Finally, we will briefly demonstrate the crucial role of gene-environment interactions in PD and discuss fusion or dual PD models. We argue that these models have the potential to significantly further our understanding of PD.
Collapse
Affiliation(s)
- Mohamed El-Gamal
- Toxicology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt. .,Medical Experimental Research Center (MERC), Faculty of Medicine, Mansoura University, Mansoura, Egypt.
| | - Mohamed Salama
- Toxicology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt.,Medical Experimental Research Center (MERC), Faculty of Medicine, Mansoura University, Mansoura, Egypt.,Global Brain Health Institute (GBHI), Trinity College Dublin (TCD), Dublin, Ireland
| | | | | | - Ahmed M Fathalla
- Department of Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Amira M Soliman
- Department of Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Wael Mohamed
- Clinical Pharmacology Department, Faculty of Medicine, Menoufia University, Mansoura, Egypt.,Department of Basic Medical Science, Kulliyyah of Medicine, International Islamic University, Kuantan, Pahang, Malaysia
| | - Ahmed A Moustafa
- School of Social Sciences and Psychology and Marcs Institute for Brain and Behaviour, Western Sydney University, Sydney, NSW, Australia.,Department of Human Anatomy and Physiology, the Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa
| |
Collapse
|
16
|
Sharma S, Wakode S, Sharma A, Nair N, Dhobi M, Wani MA, Pottoo FH. Effect of environmental toxicants on neuronal functions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:44906-44921. [PMID: 32996088 DOI: 10.1007/s11356-020-10950-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 09/20/2020] [Indexed: 05/22/2023]
Abstract
In the last few years, neurodegenerative diseases like Alzheimer's disease (AD) and Parkinson's disease (PD) have attracted attention due to their high prevalence worldwide. Environmental factors may be one of the biggest reasons for these diseases related to neuronal dysfunctions. Most of neuronal disorders are strongly associated with pre- and postnatal exposure to environmental toxins released from industries. Some of the neurotoxic metals such as lead, aluminum, mercury, manganese, cadmium, and arsenic as well as some pesticides and metal-based nanoparticles have been involved in AD and PD due to their ability to produce senile/amyloid plaques and NFTs which are the main feature of these neuronal dysfunctions. Exposure to solvents is also majorly responsible for neurodegenerative disorders. The present review highlights the impact of omnipresent heavy metals with some other neurotoxins on human health and how they give rise to neuronal dysfunctions which in turn causes socio-economic consequences due to increasing pollution worldwide. Graphical abstract.
Collapse
Affiliation(s)
- Supriya Sharma
- Department of Pharmacognosy, Delhi Pharmaceutical Sciences and Research University, Sector-3, MB road, Pushp Vihar, New Delhi, 110017, India
| | - Sharad Wakode
- Department of Pharmaceutical Chemistry, Delhi Pharmaceutical Sciences and Research University, Sector-3, MB road, Pushp Vihar, New Delhi, 110017, India
| | - Anjali Sharma
- Department of Pharmaceutical Chemistry, Delhi Pharmaceutical Sciences and Research University, Sector-3, MB road, Pushp Vihar, New Delhi, 110017, India
| | - Nisha Nair
- Department of Pharmaceutical Chemistry, Delhi Pharmaceutical Sciences and Research University, Sector-3, MB road, Pushp Vihar, New Delhi, 110017, India
| | - Mahaveer Dhobi
- Department of Pharmacognosy, Delhi Pharmaceutical Sciences and Research University, Sector-3, MB road, Pushp Vihar, New Delhi, 110017, India
| | - Mushtaq Ahmad Wani
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Kolkata, 163, Maniktala Main road, Kolkata, 700054, India
| | - Faheem Hyder Pottoo
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, P.O.BOX 1982, Damman, 31441, Saudi Arabia.
| |
Collapse
|
17
|
Horzmann KA, Portales AM, Batcho KG, Freeman JL. Developmental toxicity of trichloroethylene in zebrafish (Danio rerio). ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:728-739. [PMID: 31989135 DOI: 10.1039/c9em00565j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Trichloroethylene (TCE), an industrial solvent and degreaser, is an environmental toxicant that contaminates over half of Superfund sites, is a known carcinogen, and is linked to congenital defects and neurodegenerative disease. The developmental toxicity of TCE near ecologically relevant levels needs further characterization in order to better assess health risks of exposure. In this study, the toxicodynamics of TCE in the zebrafish (Danio rerio) model was investigated through the establishment of a LC50 concentration and by monitoring the acute developmental toxicity of ecologically relevant concentrations (0, 5, 50, and 500 parts per billion; ppb) of TCE during two different exposure lengths (1-72 hours post fertilization (hpf) and 1-120 hpf). Acute developmental toxicity was assessed by monitoring survival and hatching, larval morphology, larval heart rate, and behavioral responses during an embryonic photomotor response test and a larval visual motor response test. Embryonic exposure to TCE was associated with decreased percent hatch at 48 hpf, altered larval morphology, increased heart rate, and altered behavioral responses during the photomotor response test and visual motor response test. Larval morphology and behavioral alterations were more pronounced in the 1-120 hpf exposure length trials. The observed alterations suggest developmental TCE toxicity is still a concern at regulatory concentrations and that timing of exposure influences developmental toxicity.
Collapse
Affiliation(s)
- Katharine A Horzmann
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA.
| | | | | | | |
Collapse
|
18
|
De Miranda BR, Greenamyre JT. Trichloroethylene, a ubiquitous environmental contaminant in the risk for Parkinson's disease. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:543-554. [PMID: 31996877 PMCID: PMC7941732 DOI: 10.1039/c9em00578a] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Organic solvents are common chemicals used in industry throughout the world, however, there is evidence for adverse health effects from exposure to these compounds. Trichloroethylene (TCE) is a halogenated solvent that has been used as a degreasing agent since the early 20th century. Due to its widespread use, TCE remains one of the most significant environmental contaminants in the US, and extensive research suggests TCE is a causative factor in a number of diseases, including cancer, fetal cardiac development, and neurotoxicity. TCE has also been implicated as a possible risk factor in the development of the most common neurodegenerative movement disorder, Parkinson's disease (PD). However, there is variable concordance across multiple occupational epidemiological studies assessing TCE (or solvent) exposure and risk for PD. In addition, there remains a degree of uncertainty about how TCE elicits toxicity to the dopaminergic system. To this end, we review the specific neurotoxic mechanisms of TCE in the context of selective vulnerability of dopaminergic neurons. In addition, we consider the complexity of combined risk factors that ultimately contribute to neurodegeneration and discuss the limitations of single-factor exposure assessments.
Collapse
Affiliation(s)
- Briana R De Miranda
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, 3501 Fifth Avenue, BST-7045, Pittsburgh, 15260, Pennsylvania, USA.
| | | |
Collapse
|
19
|
Trichloroethylene and its metabolite TaClo lead to degeneration of substantia nigra dopaminergic neurones: Effects in wild type and human A30P mutant α-synuclein mice. Neurosci Lett 2019; 711:134437. [PMID: 31422098 PMCID: PMC6892271 DOI: 10.1016/j.neulet.2019.134437] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/13/2019] [Accepted: 08/14/2019] [Indexed: 11/24/2022]
Abstract
Parkinson's disease (PD) is characterised pathologically by degeneration of the dopaminergic (DA) neurones of the substantia nigra pars compacta (SNpc) and the presence of α-synuclein containing Lewy body inclusions. Trichloroethylene (TCE) has been suggested as a potential environmental chemical that may contribute to the development of PD, via conversion to the neurotoxin, 1-Trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo). We investigated the effect of an 8 week exposure to TCE or TaClo on wild type and, as an experimental model of PD, A30P mutant α-synuclein overexpressing mice using a combination of behaviour and pathology. TCE or TaClo exposure caused significant DA neuronal loss within the SNpc in both wild type and transgenic mice. Cell numbers were lower in A30P animals than wild type, however, no additive effect of TCE or TaClo exposure and A30P overexpression was found. TCE or TaClo did not appear to lead to acceleration of motor or cognitive deficits in either wild type or A30P mutant mice, potentially because of the modest reductions of DA neuronal number in the SNpc. Our results do however suggest that TCE exposure could be a possible factor in development of PD like changes following exposure.
Collapse
|
20
|
Marras C, Canning CG, Goldman SM. Environment, lifestyle, and Parkinson's disease: Implications for prevention in the next decade. Mov Disord 2019; 34:801-811. [DOI: 10.1002/mds.27720] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/17/2019] [Accepted: 04/26/2019] [Indexed: 12/14/2022] Open
Affiliation(s)
- Connie Marras
- The Edmond J. Safra Program in Parkinson's DiseaseToronto Western Hospital Toronto Ontario Canada
| | - Colleen G. Canning
- Discipline of Physiotherapy, Faculty of Health SciencesThe University of Sydney Sydney Australia
| | - Samuel M. Goldman
- School of MedicineUniversity of California–San Francisco San Francisco California USA
- Division of Occupational and Environmental MedicineSan Francisco Veterans Affairs Health Care System San Francisco California USA
| |
Collapse
|
21
|
Jiang P, Dickson DW. Parkinson's disease: experimental models and reality. Acta Neuropathol 2018; 135:13-32. [PMID: 29151169 PMCID: PMC5828522 DOI: 10.1007/s00401-017-1788-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 11/08/2017] [Accepted: 11/09/2017] [Indexed: 12/15/2022]
Abstract
Parkinson's disease (PD) is a chronic, progressive movement disorder of adults and the second most common neurodegenerative disease after Alzheimer's disease. Neuropathologic diagnosis of PD requires moderate-to-marked neuronal loss in the ventrolateral substantia nigra pars compacta and α-synuclein (αS) Lewy body pathology. Nigrostriatal dopaminergic neurodegeneration correlates with the Parkinsonian motor features, but involvement of other peripheral and central nervous system regions leads to a wide range of non-motor features. Nigrostriatal dopaminergic neurodegeneration is shared with other parkinsonian disorders, including some genetic forms of parkinsonism, but many of these disorders do not have Lewy bodies. An ideal animal model for PD, therefore, should exhibit age-dependent and progressive dopaminergic neurodegeneration, motor dysfunction, and abnormal αS pathology. Rodent models of PD using genetic or toxin based strategies have been widely used in the past several decades to investigate the pathogenesis and therapeutics of PD, but few recapitulate all the major clinical and pathologic features of PD. It is likely that new strategies or better understanding of fundamental disease processes may facilitate development of better animal models. In this review, we highlight progress in generating rodent models of PD based on impairments of four major cellular functions: mitochondrial oxidative phosphorylation, autophagy-lysosomal metabolism, ubiquitin-proteasome protein degradation, and endoplasmic reticulum stress/unfolded protein response. We attempt to evaluate how impairment of these major cellular systems contribute to PD and how they can be exploited in rodent models. In addition, we review recent cell biological studies suggesting a link between αS aggregation and impairment of nuclear membrane integrity, as observed during cellular models of apoptosis. We also briefly discuss the role of incompetent phagocytic clearance and how this may be a factor to consider in developing new rodent models of PD.
Collapse
Affiliation(s)
- Peizhou Jiang
- Neuropathology Laboratory, Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA
| | - Dennis W Dickson
- Neuropathology Laboratory, Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
| |
Collapse
|
22
|
Liu M, Shin EJ, Dang DK, Jin CH, Lee PH, Jeong JH, Park SJ, Kim YS, Xing B, Xin T, Bing G, Kim HC. Trichloroethylene and Parkinson's Disease: Risk Assessment. Mol Neurobiol 2017; 55:6201-6214. [PMID: 29270919 DOI: 10.1007/s12035-017-0830-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 12/08/2017] [Indexed: 12/21/2022]
Abstract
This study was conducted to investigate the mechanism of action and extent of selective dopaminergic neurodegeneration caused by exposure to trichloroethylene (TCE) leading to the endogenous formation of the neurotoxin 1-trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo) in rodents. Beginning at 3 months of age, male C57BL/6 mice received oral TCE dissolved in vehicle for 8 months. Dopaminergic neuronal loss was assessed by nigral tyrosine hydroxylase (TH) immunoreactivity. Selective dopaminergic neurodegeneration was determined based on histological analysis of non-dopaminergic neurons in the brain. Behavioral assays were evaluated using open field activity and rotarod tests. Mitochondrial complex I activity, oxidative stress markers, and microglial activation were also examined in the substantia nigra. The level of TaClo was detected using HPLC-electrospray ionization tandem mass spectrometry. Dopaminergic neurotoxicity of TaClo was determined in midbrain organotypic cultures from rat pups. Following 8 months of TCE treatment, there was a progressive and selective loss of 50% of the dopaminergic neurons in mouse substantia nigra (SN) and about 50% loss of dopamine and 72% loss of 3,4-dihydroxyphenylacetic acid in the striatum, respectively. In addition, motor deficits, mitochondrial impairment, oxidative stress, and inflammation were measured. TaClo content was quantified in the brain after TCE treatment. In organotypic cultures, TaClo rather than TCE induced dopaminergic neuronal loss, similar to MPP+. TCE exposure may stimulate the endogenous formation of TaClo, which is responsible for dopaminergic neurodegeneration. However, even prolonged administration of TCE was insufficient for producing a greater than 50% loss of nigral dopamine neurons, indicating that additional co-morbid factors would be needed for mimicking the profound loss of dopamine neurons seen in Parkinson's disease.
Collapse
Affiliation(s)
- Mei Liu
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Duy-Khanh Dang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Chun-Hui Jin
- Department of Geriatrics, Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151, China
| | - Phil Ho Lee
- National Creative Research Initiative Center for Catalytic Organic Reactions, Department of Chemistry, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Seok-Joo Park
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
- Ilsong Institute of Life Science, Hallym University, Anyang, 14066, Republic of Korea
| | - Yong-Sun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, 14066, Republic of Korea
| | - Bin Xing
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA
| | - Tao Xin
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, 250021, People's Republic of China
| | - Guoying Bing
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA.
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea.
| |
Collapse
|
23
|
1-Trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo) Alters Cell Cycle Progression in Human Neuroblastoma Cell Lines. Neurotox Res 2017; 32:649-660. [PMID: 28721631 DOI: 10.1007/s12640-017-9782-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/20/2017] [Accepted: 07/05/2017] [Indexed: 12/18/2022]
Abstract
1-Trichloromethyl-1,2,3,4-tetrahydro-β-carboline, abbreviated as TaClo, is an endogenous neurotoxin capable of formation in the brain through the condensation of neuronal tryptamine with ingested exogenous toxins such as trichloroethylene or chloral hydrate. Due to its structural resemblance to 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP), and similar ability to inhibit mitochondrial complex I, TaClo has been implicated in the etiology of Parkinson's disease. Previous studies have shown the cytotoxicity of TaClo in various cell culture models. In this study, we were interested in identifying the early molecular events within the cell upon exposure to TaClo, a potent mitochondrial toxin. We found increased phosphorylation of 5'-adenosine monophosphate-activated protein kinase (AMPK), induction of autophagy, and a dependence on glycolysis as some of the downstream events to TaClo treatment. Furthermore, TaClo-treated cells undergo accelerated late proliferation but form daughter cells containing fewer neurites, leading to their eventual apoptosis. We also found that TaClo inhibits neuronal prostaglandin E2 synthesis which may play an important role in synaptic plasticity. These results show that TaClo-mediated inhibition of mitochondrial complex I have multiple effects on cellular physiology which are in line with other mitochondrial effectors of Parkinson's disease.
Collapse
|
24
|
Frye RE, Rose S, Wynne R, Bennuri SC, Blossom S, Gilbert KM, Heilbrun L, Palmer RF. Oxidative Stress Challenge Uncovers Trichloroacetaldehyde Hydrate-Induced Mitoplasticity in Autistic and Control Lymphoblastoid Cell Lines. Sci Rep 2017; 7:4478. [PMID: 28667285 PMCID: PMC5493637 DOI: 10.1038/s41598-017-04821-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/19/2017] [Indexed: 12/11/2022] Open
Abstract
Mitoplasticity occurs when mitochondria adapt to tolerate stressors. Previously we hypothesized that a subset of lymphoblastoid cell lines (LCLs) from children with autistic disorder (AD) show mitoplasticity (AD-A), presumably due to previous environmental exposures; another subset of AD LCLs demonstrated normal mitochondrial activity (AD-N). To better understand mitoplasticity in the AD-A LCLs we examined changes in mitochondrial function using the Seahorse XF96 analyzer in AD and Control LCLs after exposure to trichloroacetaldehyde hydrate (TCAH), an in vivo metabolite of the environmental toxicant and common environmental pollutant trichloroethylene. To better understand the role of reactive oxygen species (ROS) in mitoplasticity, TCAH exposure was followed by acute exposure to 2,3-dimethoxy-1,4-napthoquinone (DMNQ), an agent that increases ROS. TCAH exposure by itself resulted in a decline in mitochondrial respiration in all LCL groups. This effect was mitigated when TCAH was followed by acute DMNQ exposure but this varied across LCL groups. DMNQ did not affect AD-N LCLs, while it neutralized the detrimental effect of TCAH in Control LCLs and resulted in a increase in mitochondrial respiration in AD-A LCLs. These data suggest that acute increases in ROS can activate mitochondrial protective pathways and that AD-A LCLs are better able to activate these protective pathways.
Collapse
Affiliation(s)
- Richard Eugene Frye
- Arkansas Children's Research Institute, Little Rock, AR, USA. .,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
| | - Shannon Rose
- Arkansas Children's Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Rebecca Wynne
- Arkansas Children's Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Sirish C Bennuri
- Arkansas Children's Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Sarah Blossom
- Arkansas Children's Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Kathleen M Gilbert
- Arkansas Children's Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Lynne Heilbrun
- Department of Family and Community Medicine, University of Texas Health Science Center, San Antonio, TX, USA
| | - Raymond F Palmer
- Department of Family and Community Medicine, University of Texas Health Science Center, San Antonio, TX, USA
| |
Collapse
|
25
|
Hartman JH, Miller GP, Meyer JN. Toxicological Implications of Mitochondrial Localization of CYP2E1. Toxicol Res (Camb) 2017; 6:273-289. [PMID: 28989700 DOI: 10.1039/c7tx00020k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cytochrome P450 2E1 (CYP2E1) metabolizes an extensive array of pollutants, drugs, and other small molecules, often resulting in bioactivation to reactive metabolites. Therefore, it is unsurprising that it has been the subject of decades of research publications and reviews. However, while CYP2E1 has historically been studied in the endoplasmic reticulum (erCYP2E1), active CYP2E1 is also present in mitochondria (mtCYP2E1). Relatively few studies have specifically focused on mtCYP2E1, but there is growing interest in this form of the enzyme as a driver in toxicological mechanisms given its activity and location. Many previous studies have linked total CYP2E1 to conditions that involve mitochondrial dysfunction (fasting, diabetes, non-alcoholic steatohepatitis, and obesity). Furthermore, a large number of reactive metabolites that are formed by CYP2E1 through metabolism of drugs and pollutants have been demonstrated to cause mitochondrial dysfunction. Finally, there appears to be significant inter-individual variability in targeting to the mitochondria, which could constitute a source of variability in individual response to exposures. This review discusses those outcomes, the biochemical properties and toxicological consequences of mtCYP2E1, and highlights important knowledge gaps and future directions. Overall, we feel that this exciting area of research is rich with new and important questions about the relationship between mtCYP2E1, mitochondrial dysfunction, and pathology.
Collapse
Affiliation(s)
| | - Grover P Miller
- Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR
| | - Joel N Meyer
- Nicholas School of the Environment, Duke University, Durham, NC
| |
Collapse
|
26
|
Reis J, Benbrick E, Bonneterre V, Spencer P. Parkinson's disease and solvents: Is there a causal link? Rev Neurol (Paris) 2016; 172:761-765. [DOI: 10.1016/j.neurol.2016.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/30/2016] [Accepted: 09/27/2016] [Indexed: 02/07/2023]
|
27
|
Otsuki N, Homma T, Fujiwara H, Kaneko K, Hozumi Y, Shichiri M, Takashima M, Ito J, Konno T, Kurahashi T, Yoshida Y, Goto K, Fujii S, Fujii J. Trichloroethylene exposure aggravates behavioral abnormalities in mice that are deficient in superoxide dismutase. Regul Toxicol Pharmacol 2016; 79:83-90. [PMID: 27166294 DOI: 10.1016/j.yrtph.2016.05.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/03/2016] [Accepted: 05/04/2016] [Indexed: 12/11/2022]
Abstract
Trichloroethylene (TCE) has been implicated as a causative agent for Parkinson's disease (PD). The administration of TCE to rodents induces neurotoxicity associated with dopaminergic neuron death, and evidence suggests that oxidative stress as a major player in the progression of PD. Here we report on TCE-induced behavioral abnormality in mice that are deficient in superoxide dismutase 1 (SOD1). Wild-type (WT) and SOD1-deficient (Sod1(-/-)) mice were intraperitoneally administered TCE (500 mg/kg) over a period of 4 weeks. Although the TCE-administrated Sod1(-/-) mice showed marked abnormal motor behavior, no significant differences were observed among the experimental groups by biochemical and histopathological analyses. However, treating mouse neuroblastoma-derived NB2a cells with TCE resulted in the down regulation of the SOD1 protein and elevated oxidative stress under conditions where SOD1 production was suppressed. Taken together, these data indicate that SOD1 plays a pivotal role in protecting motor neuron function against TCE toxicity.
Collapse
Affiliation(s)
- Noriyuki Otsuki
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
| | - Takujiro Homma
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
| | - Hiroki Fujiwara
- Department of Physiology, Yamagata University School of Medicine, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
| | - Kenya Kaneko
- Department of Physiology, Yamagata University School of Medicine, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
| | - Yasukazu Hozumi
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Iidanishi 2-2-2, Yamagata 990-9585, Japan
| | - Mototada Shichiri
- Health Research Institute (HRI), National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan
| | - Mizuki Takashima
- Health Research Institute (HRI), National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan
| | - Junitsu Ito
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
| | - Tasuku Konno
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
| | - Toshihiro Kurahashi
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
| | - Yasukazu Yoshida
- Health Research Institute (HRI), National Institute of Advanced Industrial Science and Technology (AIST), 2217-14 Hayashi-cho, Takamatsu, Kagawa 761-0395, Japan
| | - Kaoru Goto
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Iidanishi 2-2-2, Yamagata 990-9585, Japan
| | - Satoshi Fujii
- Department of Physiology, Yamagata University School of Medicine, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
| | - Junichi Fujii
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, 2-2-2 Iidanishi, Yamagata 990-9585, Japan.
| |
Collapse
|
28
|
Abstract
Worldwide, several hundred million tons of organic solvents are used annually in household, industry, and other occupational settings. Millions of workers are regularly exposed to organic solvents considered neurotoxic. Acute neurotoxicity due to high exposure of solvent is usually evident, but the nature of long-term effects, such as chronic solvent encephalopathy (CSE), has raised uncertainty even among experts. Earlier studies were criticized for their methodology, mainly epidemiologic studies or investigations of exposed groups with many possible confounders and inadequate exposure assessment. However, an increasing number of studies have been performed since, also on workers with defined CSE based on differential diagnostics. During the last decade, evidence has emerged to enable identification of CSE, a necessity for the early recognition and prevention of progression of dysfunction and disability. Selected chemicals are presented here due to their widespread use, neurotoxic potential, and ability to cause solvent encephalopathy. Constant introduction of new chemicals may introduce new hazardous chemicals or known chemicals may reveal new health effects. It is important to keep an open mind for new findings of solvent-related neurobehavioral effects.
Collapse
|
29
|
Abstract
In recent years, the contribution of exposure to environmental toxicants has been recognized as a significant contributor to the etiopathogenesis of parkinsonism. Of these toxicants, exposure to pesticides, metals, solvents used in manufacturing processes, as well as flame-retardant chemicals used in consumer and commercial products, has received the greatest attention as possible risk factors. Related to this, individuals who are exposed to these compounds at high concentrations or for prolonged periods of time in an occupational setting appear to be one of the more vulnerable populations to these effects. Our understanding of which compounds are involved and the potential molecular pathways that are susceptible to these chemicals and may underlie the pathogenesis has greatly improved. However, there are still hundreds of chemicals that we are exposed to in the environment for which we do not have any information on their potential neurotoxicity on the nigrostriatal dopamine system. Thus, using our past accomplishments as a blueprint, future endeavors should focus on elaborating upon these initial findings in order to identify specific and relevant chemical toxicants in our environment that can impact the risk of parkinsonism and work towards a means to attenuate or abolish their effects on the human population.
Collapse
Affiliation(s)
- W Michael Caudle
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
| |
Collapse
|
30
|
Abstract
Parkinson's disease (PD) is a chronic, progressive, disabling neurodegenerative disorder that begins in mid to late life and is characterized by motor impairment, autonomic dysfunction, and, in many, psychological and cognitive changes. Recent advances have helped delineate pathogenetic mechanisms, yet the cause of PD in most individuals is unknown. Although at least 15 genes and genetic loci have been associated with PD, identified genetic causes are responsible for only a few percent of cases. Epidemiologic studies have found increased risk of PD associated with exposure to environmental toxicants such as pesticides, solvents, metals, and other pollutants, and many of these compounds recapitulate PD pathology in animal models. This review summarizes the environmental toxicology of PD, highlighting the consistency of observations across cellular, animal, and human studies of PD pathogenesis.
Collapse
|
31
|
Lock EA, Zhang J, Checkoway H. Solvents and Parkinson disease: a systematic review of toxicological and epidemiological evidence. Toxicol Appl Pharmacol 2013; 266:345-55. [PMID: 23220449 PMCID: PMC3621032 DOI: 10.1016/j.taap.2012.11.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 11/12/2012] [Accepted: 11/14/2012] [Indexed: 12/25/2022]
Abstract
Parkinson disease (PD) is a debilitating neurodegenerative motor disorder, with its motor symptoms largely attributable to loss of dopaminergic neurons in the substantia nigra. The causes of PD remain poorly understood, although environmental toxicants may play etiologic roles. Solvents are widespread neurotoxicants present in the workplace and ambient environment. Case reports of parkinsonism, including PD, have been associated with exposures to various solvents, most notably trichloroethylene (TCE). Animal toxicology studies have been conducted on various organic solvents, with some, including TCE, demonstrating potential for inducing nigral system damage. However, a confirmed animal model of solvent-induced PD has not been developed. Numerous epidemiologic studies have investigated potential links between solvents and PD, yielding mostly null or weak associations. An exception is a recent study of twins indicating possible etiologic relations with TCE and other chlorinated solvents, although findings were based on small numbers, and dose-response gradients were not observed. At present, there is no consistent evidence from either the toxicological or epidemiologic perspective that any specific solvent or class of solvents is a cause of PD. Future toxicological research that addresses mechanisms of nigral damage from TCE and its metabolites, with exposure routes and doses relevant to human exposures, is recommended. Improvements in epidemiologic research, especially with regard to quantitative characterization of long-term exposures to specific solvents, are needed to advance scientific knowledge on this topic.
Collapse
Affiliation(s)
- Edward A Lock
- Liverpool John Moores University, School of Pharmacy and Biomolecular Sciences, Byrom Street, Liverpool, UK.
| | | | | |
Collapse
|
32
|
Goldman SM, Quinlan PJ, Ross GW, Marras C, Meng C, Bhudhikanok GS, Comyns K, Korell M, Chade AR, Kasten M, Priestley B, Chou KL, Fernandez HH, Cambi F, Langston JW, Tanner CM. Solvent exposures and Parkinson disease risk in twins. Ann Neurol 2012; 71:776-84. [PMID: 22083847 PMCID: PMC3366287 DOI: 10.1002/ana.22629] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 08/18/2011] [Accepted: 09/02/2011] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Several case reports have linked solvent exposure to Parkinson disease (PD), but few studies have assessed associations with specific agents using an analytic epidemiologic design. We tested the hypothesis that exposure to specific solvents is associated with PD risk using a discordant twin pair design. METHODS Ninety-nine twin pairs discordant for PD ascertained from the National Academy of Sciences/National Research Council World War II Veteran Twins Cohort were interviewed regarding lifetime occupations and hobbies using detailed job task-specific questionnaires. Exposures to 6 specific solvents selected a priori were estimated by expert raters unaware of case status. RESULTS Ever exposure to trichloroethylene (TCE) was associated with significantly increased risk of PD (odds ratio [OR], 6.1; 95% confidence interval [CI] 1.2-33; p = 0.034), and exposure to perchloroethylene (PERC) and carbon tetrachloride (CCl(4) ) tended toward significance (respectively: OR, 10.5; 95% CI, 0.97-113; p = 0.053; OR, 2.3; 95% CI, 0.9-6.1; p = 0.088). Results were similar for estimates of exposure duration and cumulative lifetime exposure. INTERPRETATION Exposure to specific solvents may increase risk of PD. TCE is the most common organic contaminant in groundwater, and PERC and CCl(4) are also ubiquitous in the environment. Our findings require replication in other populations with well-characterized exposures, but the potential public health implications are substantial.
Collapse
Affiliation(s)
- Samuel M Goldman
- The Parkinson's Institute, 675 Almanor Avenue, Sunnyvale, CA 94085, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Industrial toxicants and Parkinson's disease. Neurotoxicology 2012; 33:178-88. [PMID: 22309908 DOI: 10.1016/j.neuro.2012.01.010] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/19/2012] [Accepted: 01/23/2012] [Indexed: 11/22/2022]
Abstract
The exposure of the human population to environmental contaminants is recognized as a significant contributing factor for the development of Parkinson's disease (PD) and other forms of parkinsonism. While pesticides have repeatedly been identified as risk factors for PD, these compounds represent only a subset of environmental toxicants that we are exposed to on a regular basis. Thus, non-pesticide contaminants, such as metals, solvents, and other organohalogen compounds have also been implicated in the clinical and pathological manifestations of these movement disorders and it is these non-pesticide compounds that are the subject of this review. As toxic exposures to these classes of compounds can result in a spectrum of PD or PD-related disorders, it is imperative to appreciate shared clinico-pathological characteristics or mechanisms of action of these compounds in order to further delineate the resultant disorders as well as identify improved preventive strategies or therapeutic interventions.
Collapse
|
34
|
Keane PC, Judge SJ, Blain PG, Morris CM. An investigation into the mechanism of trichloroethylene neurotoxicity in relation to Parkinsonism. Toxicology 2011. [DOI: 10.1016/j.tox.2011.09.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
35
|
A review of potential neurotoxic mechanisms among three chlorinated organic solvents. Toxicol Appl Pharmacol 2011; 255:113-26. [DOI: 10.1016/j.taap.2011.05.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 05/06/2011] [Accepted: 05/08/2011] [Indexed: 12/17/2022]
|
36
|
Abstract
Multiple genetic and environmental etiologies have been implicated in the pathogenesis of idiopathic Parkinson disease. Recent observations have suggested an association between chronic exposure to trichloroethylene (TCE) and development of clinical parkinsonism. Animal models of TCE exposure have shown nigrostriatal degeneration and the development of parkinsonian features. Animal and cell culture models indicate mitochondrial dysfunction as the probable mechanism, most likely mediated by TaClo, a potential TCE metabolite. These observations endorse the hypothesis that a variety of environmental risk factors may cause nigrostriatal degeneration and clinical parkinsonism in genetically predisposed individuals.
Collapse
Affiliation(s)
- Fariha Zaheer
- Movement Disorders Program, Department of Neurology, University of Kentucky College of Medicine, Kentucky Clinic L-445, 740 South Limestone Street, Lexington, KY 40536-0284, USA
| | | |
Collapse
|
37
|
Antony PMA, Diederich NJ, Balling R. Parkinson's disease mouse models in translational research. Mamm Genome 2011; 22:401-19. [PMID: 21559878 PMCID: PMC3151483 DOI: 10.1007/s00335-011-9330-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 04/14/2011] [Indexed: 12/21/2022]
Abstract
Animal models with high predictive power are a prerequisite for translational research. The closer the similarity of a model to Parkinson’s disease (PD), the higher is the predictive value for clinical trials. An ideal PD model should present behavioral signs and pathology that resemble the human disease. The increasing understanding of PD stratification and etiology, however, complicates the choice of adequate animal models for preclinical studies. An ultimate mouse model, relevant to address all PD-related questions, is yet to be developed. However, many of the existing models are useful in answering specific questions. An appropriate model should be chosen after considering both the context of the research and the model properties. This review addresses the validity, strengths, and limitations of current PD mouse models for translational research.
Collapse
Affiliation(s)
- Paul M A Antony
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Luxembourg.
| | | | | |
Collapse
|
38
|
|
39
|
Liu M, Choi DY, Hunter RL, Pandya JD, Cass WA, Sullivan PG, Kim HC, Gash DM, Bing G. Trichloroethylene induces dopaminergic neurodegeneration in Fisher 344 rats. J Neurochem 2009; 112:773-83. [PMID: 19922440 DOI: 10.1111/j.1471-4159.2009.06497.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Trichloroethylene, a chlorinated solvent widely used as a degreasing agent, is a common environmental contaminant. Emerging evidence suggests that chronic exposure to trichloroethylene may contribute to the development of Parkinson's disease. The purpose of this study was to determine if selective loss of nigrostriatal dopaminergic neurons could be reproduced by systemic exposure of adult Fisher 344 rats to trichloroethylene. In our experiments, oral administration of trichloroethylene induced a significant loss of dopaminergic neurons in the substantia nigra pars compacta in a dose-dependent manner, whereas the number of both cholinergic and GABAergic neurons were not decreased in the striatum. There was a robust decline in striatal levels of 3, 4-dihydroxyphenylacetic acid without a significant depletion of striatal dopamine. Rats treated with trichloroethylene showed defects in rotarod behavior test. We also found a significantly reduced mitochondrial complex I activity with elevated oxidative stress markers and activated microglia in the nigral area. In addition, we observed intracellular alpha-synuclein accumulation in the dorsal motor nucleus of the vagus nerve, with some in nigral neurons, but little in neurons of cerebral cortex. Overall, our animal model exhibits some important features of Parkinsonism, and further supports that trichloroethylene may be an environmental risk factors for Parkinson's disease.
Collapse
Affiliation(s)
- Mei Liu
- Department of Anatomy and Neurobiology, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Gash DM, Rutland K, Hudson NL, Sullivan PG, Bing G, Cass WA, Pandya JD, Liu M, Choi DY, Hunter RL, Gerhardt GA, Smith CD, Slevin JT, Prince TS. Trichloroethylene: Parkinsonism and complex 1 mitochondrial neurotoxicity. Ann Neurol 2008; 63:184-92. [PMID: 18157908 DOI: 10.1002/ana.21288] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To analyze a cluster of 30 industrial coworkers with Parkinson's disease and parkinsonism subjected to long-term (8-33 years) chronic exposure to trichloroethylene. METHODS Neurological evaluations were conducted on the 30 coworkers, including a general physical and neurological examination and the Unified Parkinson's Disease Rating Scale. In addition, fine motor speed was quantified and an occupational history survey was administered. Next, animal studies were conducted to determine whether trichloroethylene exposure is neurotoxic to the nigrostriatal dopamine system that degenerates in Parkinson's disease. The experiments specifically analyzed complex 1 mitochondrial neurotoxicity because this is a mechanism of action of other known environmental dopaminergic neurotoxins. RESULTS The three workers with workstations adjacent to the trichloroethylene source and subjected to chronic inhalation and dermal exposure from handling trichloroethylene-soaked metal parts had Parkinson's disease. Coworkers more distant from the trichloroethylene source, receiving chronic respiratory exposure, displayed many features of parkinsonism, including significant motor slowing. Neurotoxic actions of trichloroethylene were demonstrated in accompanying animal studies showing that oral administration of trichloroethylene for 6 weeks instigated selective complex 1 mitochondrial impairment in the midbrain with concomitant striatonigral fiber degeneration and loss of dopamine neurons. INTERPRETATION Trichloroethylene, used extensively in industry and the military and a common environmental contaminant, joins other mitochondrial neurotoxins, MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) and some pesticides, as a risk factor for parkinsonism.
Collapse
Affiliation(s)
- Don M Gash
- Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY 40536, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Kochen W, Kohlmüller D, De Biasi P, Ramsay R. The endogeneous formation of highly chlorinated tetrahydro-beta-carbolines as a possible causative mechanism in idiopathic Parkinson's disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 527:253-63. [PMID: 15206739 DOI: 10.1007/978-1-4615-0135-0_29] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The causative interrelationship between long-term, low level exposure to chlorinated volatile organic solvents (VOSs) and neurodegenerative diseases (polyneuropathy, encephalopathy) are still an issue of controversial debate. Endogeneously formed chlorinated tetrahydro-beta-carbolines found by Bringmann 1995 (TaClo hypothesis) may contribute, in particular, to the development of (idiopathic) Parkinson's disease (PD) in the presence of the sufficient amount of trichloroacetaldehyde, an intermediate in metabolism of trichloroethylene (TRI). Long-term storage of specific VOSs over years, evident frrom exhalation pattern during the postexposure period, may serve as a promoting factor to form continuously TaClo non-enzymatically from tryptamine and trichloroacetaldehyde. Thus, the induction of TaClo-mediated neurotoxic processes extends over years. The onset of Parkinson's disease in three chronic TRI-exposed individuals during the postexposure period could be associated with the presence of TaClo in ng-range. Consequently, determination of TaClo and its derivatives in blood of humans exposed to chlorinated VOSs may serve as a marker of risk indicating either causative or supportive processes of neurodegeneration that may lead to manifestation of PD after many years.
Collapse
Affiliation(s)
- Walter Kochen
- Children's Hospital, Clinical Chemistry, University of Heidelberg, Germany.
| | | | | | | |
Collapse
|
42
|
Abstract
Parkinson's disease is an increasingly common disease of elderly patients who present a particular anaesthetic challenge. This review explores the epidemiology, aetiology, pathogenesis, and pathophysiology of the condition, particularly the possible role of genetic factors. The clinical features are described in detail and recent advances in medical management are highlighted. Controversies surrounding the use of the newer drugs and possible advances in neurosurgical interventions are discussed. Particular anaesthetic problems in patients with Parkinson's disease are respiratory, cardiovascular, and neurological. Potential drug interactions are described and recommendations are made about suitable anaesthetic techniques.
Collapse
Affiliation(s)
- G Nicholson
- Department of Anaesthesia and Intensive Care Medicine, St George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK.
| | | | | |
Collapse
|
43
|
Abstract
Idiopathic Parkinson's disease (PD), one of the most common neurodegenerative disorders associated with aging, is characterized neurochemically by abnormal and profound loss of nigrostriatal dopamine (DA) neurons. A prominent current view is that the excessive degeneration of the dopaminergic system is the outcome of extended insults by environmental neurotoxins or endogenous neurotoxic factors in genetically vulnerable or susceptible individuals. Recent insights into the identities and mechanisms of potential neurotoxic species, which span pesticides, environmental contaminants including heterocyclic amines with beta-carboline (betaC) and isoquinoline (IQ) structures, endogenous DA metabolites or intermediates, neuromelanin, metals, and infectious agents, are presented.
Collapse
Affiliation(s)
- Michael A Collins
- Department of Cell Biology, Neurobiology, and Anatomy, Division of Biochemistry, Loyola University School of Medicine, 2160 South First Avenue, Maywood, IL 60153, USA.
| | | |
Collapse
|
44
|
Riederer P, Foley P, Bringmann G, Feineis D, Brückner R, Gerlach M. Biochemical and pharmacological characterization of 1-trichloromethyl-1,2,3,4-tetrahydro-beta-carboline: a biologically relevant neurotoxin? Eur J Pharmacol 2002; 442:1-16. [PMID: 12020676 DOI: 10.1016/s0014-2999(02)01308-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Acute and long-term effects of exposure to reactive compounds as the result of environmental pollution, workplace conditions or dietary intake are suspected to be involved in the etiology of a variety of disorders, including neurodegenerative disorders such as Parkinson's disease. The recognition in 1970s that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a neurotoxic by-product of illicit meperidine synthesis, elicits parkinsonian symptoms in primates, including man, prompted the search for naturally occurring analogs which might be involved in human disease. It has been suggested that one candidate, 1-trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo), a potent dopaminergic neurotoxin, might be formed endogenously in humans following the administration of the hypnotic chloral hydrate or after the exposure to the industrial solvent trichloroethylene. Such spontaneous formation has, indeed, been recently reported. The biochemical and pharmacological characteristics of TaClo and related compounds are thus reviewed here, and their potential significance for human neurodegenerative disease discussed.
Collapse
Affiliation(s)
- Peter Riederer
- Clinical Neurochemistry, Department of Psychiatry, University of Würzburg, Füchsleinstrasse 15, Würzburg, Germany.
| | | | | | | | | | | |
Collapse
|