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Macedo MB, Cunha EO, Reis AD, Machado MS, de Campos D, Malysz T, Dallegrave E. Morphometric Evaluation of the Recurrent Laryngeal Nerve of Wistar Rats Exposed to Pesticides. J Voice 2024; 38:264-272. [PMID: 34782225 DOI: 10.1016/j.jvoice.2021.09.028] [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: 06/14/2021] [Revised: 09/09/2021] [Accepted: 09/23/2021] [Indexed: 10/19/2022]
Abstract
The literature has been shown that exposition by inhalation to chemical compounds can cause vocal disorders and dysphagia in humans, in addition to other symptoms that are manifested according to the type, concentration and duration of exposure to the substance. Cypermethrin and dichlorvos are pesticides widely used in agriculture, public health, veterinary, and home environments. Despite the scientific evidence that cypermethrin and dichlorvos can cause neurodegenerative damage and motor alterations, there are no studies evaluating the toxic effects of these pesticides on the morphology of structures responsible for vocal mobility, especially to the Recurrent Laryngeal Nerve (RLN). Considering the association between vocal disorders in humans and variations in RLN and morphometry, the aim of this study was to evaluate the possible alterations in the microstructure of RLN secondary to subchronic exposure to cypermethrin (pyrethroid) and dichlorvos (organophosphate) in Wistar rats. The experimental protocol (approved by CEUA-UFCSPA: 321/15 and 323/15) consisted of 15 male Wistar rats, allocated in 3 groups: Control (n = 5, exposed to water), Cypermethrin (n = 5, exposed to cypermethrin - 1/10 of the inhalation median lethal concentration [LC50] - 0.25 mg/L) and dichlorvos (n = 5, exposed to dichlorvos - 1/10 of the LC50 - 1.5 mg/L). Inhalation exposure was performed for 4 hours, 5 times per week, for 6 weeks. The nerves were collected, histologically processed and analyzed using morphometric parameters measured using ZEN 2.6 (Zeiss - Germany). The cypermethrin and dichlorvos groups showed significant changes (P < 0.001, ANOVA) in the g-ratio and in the thickness of the myelin sheath of the RLN when compared to the control animals, however, none of the other parameters evaluated showed statistically significant differences. These findings indicate that repeated inhalation exposure to commercial products of cypermethrin and dichlorvos is able to modify the structure of the RLN and possibly generating vocal changes and / or dysphagia.
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Affiliation(s)
- Mateus Belmonte Macedo
- Graduate Program in Pathology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil; Laboratory of Research in Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
| | - Eduarda Oliveira Cunha
- Graduate Program in Health Sciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil; Laboratory of Research in Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
| | - Aléxia Dos Reis
- Graduate Program in Pathology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil; Laboratory of Research in Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
| | - Márcia Salgado Machado
- Department of Speech Therapy and Audiology, University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil; Laboratory of Research in Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
| | - Deivis de Campos
- Department of Basic Health Sciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil; Department of Life Sciences, University of Santa Cruz do Sul (UNISC), Santa Cruz do Sul, RS, Brazil; Graduate Program in Health Promotion, University of Santa Cruz do Sul (UNISC), Santa Cruz do Sul, RS, Brazil
| | - Taís Malysz
- Graduate Program in Neurosciences, Basic Health Sciences Institute, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Eliane Dallegrave
- Graduate Program in Pathology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil; Graduate Program in Health Sciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil; Department of Pharmacosciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil; Laboratory of Research in Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.
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Burdon J, Budnik LT, Baur X, Hageman G, Howard CV, Roig J, Coxon L, Furlong CE, Gee D, Loraine T, Terry AV, Midavaine J, Petersen H, Bron D, Soskolne CL, Michaelis S. Health consequences of exposure to aircraft contaminated air and fume events: a narrative review and medical protocol for the investigation of exposed aircrew and passengers. Environ Health 2023; 22:43. [PMID: 37194087 PMCID: PMC10186727 DOI: 10.1186/s12940-023-00987-8] [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: 12/21/2022] [Accepted: 03/31/2023] [Indexed: 05/18/2023]
Abstract
Thermally degraded engine oil and hydraulic fluid fumes contaminating aircraft cabin air conditioning systems have been well documented since the 1950s. Whilst organophosphates have been the main subject of interest, oil and hydraulic fumes in the air supply also contain ultrafine particles, numerous volatile organic hydrocarbons and thermally degraded products. We review the literature on the effects of fume events on aircrew health. Inhalation of these potentially toxic fumes is increasingly recognised to cause acute and long-term neurological, respiratory, cardiological and other symptoms. Cumulative exposure to regular small doses of toxic fumes is potentially damaging to health and may be exacerbated by a single higher-level exposure. Assessment is complex because of the limitations of considering the toxicity of individual substances in complex heated mixtures.There is a need for a systematic and consistent approach to diagnosis and treatment of persons who have been exposed to toxic fumes in aircraft cabins. The medical protocol presented in this paper has been written by internationally recognised experts and presents a consensus approach to the recognition, investigation and management of persons suffering from the toxic effects of inhaling thermally degraded engine oil and other fluids contaminating the air conditioning systems in aircraft, and includes actions and investigations for in-flight, immediately post-flight and late subsequent follow up.
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Affiliation(s)
- Jonathan Burdon
- Respiratory Physician, St Vincent's Private Hospital, East Melbourne, Australia
| | - Lygia Therese Budnik
- Institute for Occupational and Maritime Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Xaver Baur
- European Society for Environmental and Occupational Medicine, Berlin, Germany
- University of Hamburg, Hamburg, Germany
| | - Gerard Hageman
- Department of Neurology, Medisch Spectrum Twente, Hospital Enschede, Enschede, The Netherlands
| | - C Vyvyan Howard
- Centre for Molecular Biosciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Jordi Roig
- Department of Pulmonary Medicine, Clínica Creu Blanca, Barcelona, Spain
| | - Leonie Coxon
- Clinical and Forensic Psychologist, Mount Pleasant Psychology, Perth, Australia
| | - Clement E Furlong
- Departments of Medicine (Div. Medical Genetics) and Genome Sciences, University of Washington, Seattle, USA
| | - David Gee
- Centre for Pollution Research and Policy, Visiting Fellow, Brunel University, London, UK
| | - Tristan Loraine
- Technical Consultant, Spokesperson for the Global Cabin Air Quality Executive, London, UK
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, USA
| | | | - Hannes Petersen
- Faculty of Medicine, University of Iceland, Akureyri Hospital, Akureyri, Iceland
| | - Denis Bron
- Federal Department of Defence, Civil Protection and Sport (DDPS), Aeromedical Institute (FAI)/AeMC, Air Force, Dübendorf, Switzerland
| | - Colin L Soskolne
- School of Public Health, University of Alberta, Edmonton, AB, Canada
| | - Susan Michaelis
- Occupational and Environmental Health Research Group, Honorary Senior Research Fellow, University of Stirling, Scotland / Michaelis Aviation Consulting, West Sussex, England.
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Lockridge O, Schopfer LM. Review: Organophosphorus toxicants, in addition to inhibiting acetylcholinesterase activity, make covalent adducts on multiple proteins and promote protein crosslinking into high molecular weight aggregates. Chem Biol Interact 2023; 376:110460. [PMID: 36963650 PMCID: PMC10100150 DOI: 10.1016/j.cbi.2023.110460] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 03/08/2023] [Accepted: 03/15/2023] [Indexed: 03/26/2023]
Abstract
The acute effects of exposure to organophosphorus toxicants are explained by inhibition of acetylcholinesterase activity. However, the mechanisms that explain long term illness associated with organophosphorus exposure are still under investigation. We find that organophosphorus nerve agents and organophosphorus pesticides make covalent adducts not only on the serine from acetylcholinesterase, but also on tyrosine, lysine, glutamate, serine and threonine from a variety of proteins. Almost any protein can be modified by a high dose of organophosphorus toxicant. A low dose of 10 μM chlorpyrifos oxon added to the serum-free culture medium of human neuroblastoma SH-SY5Y cells resulted in tyrosine adducts on 48 proteins immunopurified from the cell lysate. We identified the adducted proteins by mass spectrometry after immunopurifying modified proteins with a rabbit anti-diethoxyphospho-tyrosine monoclonal antibody which biased this study for tyrosine adducts. In cultured cells, the primary organophosphate targets are abundant proteins. Organophosphate-modified proteins may disrupt physiological processes. In separate experiments we identified organophosphate adducts on lysine. Organophosphylation activates the lysine for protein crosslinking. The activated lysine reacts with glutamic acid or aspartic acid protein side chains to form an isopeptide bond between proteins, resulting in high molecular weight crosslinked proteins. Crosslinked proteins form insoluble aggregates that may lead to neurogenerative disease.
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Affiliation(s)
- Oksana Lockridge
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
| | - Lawrence M Schopfer
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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4
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Elhaj R, Reynolds JM. Chemical exposures and suspected impact on Gulf War Veterans. Mil Med Res 2023; 10:11. [PMID: 36882803 PMCID: PMC9993698 DOI: 10.1186/s40779-023-00449-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 02/24/2023] [Indexed: 03/09/2023] Open
Abstract
Gulf War Illness (GWI) encompass a spectrum of maladies specific to troops deployed during the Persian Gulf War (1990-1991). There are several hypothesized factors believed to contribute to GWI, including (but not limited to) exposures to chemical agents and a foreign environment (e.g., dust, pollens, insects, and microbes). Moreover, the inherent stress associated with deployment and combat has been associated with GWI. While the etiology of GWI remains uncertain, several studies have provided strong evidence that chemical exposures, especially neurotoxicants, may be underlying factors for the development of GWI. This mini style perspective article will focus on some of the major evidence linking chemical exposures to GWI development and persistence decades after exposure.
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Affiliation(s)
- Rami Elhaj
- Center for Cancer Biology, Immunology and Infection, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA
| | - Joseph M Reynolds
- Center for Cancer Biology, Immunology and Infection, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA.
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Heroin Addiction Induces Axonal Transport Dysfunction in the Brain Detected by In Vivo MRI. Neurotox Res 2022; 40:1070-1085. [PMID: 35759084 DOI: 10.1007/s12640-022-00533-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/13/2022] [Accepted: 06/13/2022] [Indexed: 10/17/2022]
Abstract
Heroin is a highly addictive drug that causes axonal damage. Here, manganese-enhanced magnetic resonance imaging (MEMRI) was used to dynamically monitor axonal transport at different stages of heroin addiction. Rat models of heroin addiction (HA) and prolonged heroin addiction (PHA) were established by injecting rats with heroin at different stages. Heroin-induced learning and memory deficits were evaluated in the Morris water maze (MWM), and MEMRI was used to dynamically evaluate axonal transport in the olfactory pathway. The expression of proteins related to axonal structure and function was also assessed by Western blotting. Transmission electron microscopy (TEM) was used to observe ultrastructural changes, and protein levels of neurofilament heavy chain (NF-H) were analyzed by immunofluorescence staining. HA rats, especially PHA rats, exhibited worse spatial learning and memory than control rats. Compared with HA rats and control rats, PHA rats exhibited significantly longer escape latencies, significantly fewer platform-location crossings, and significantly more time in the target quadrant during the MWM test. Mn2+ transport was accelerated in HA rats. PHA rats exhibited severely reduced Mn2+ transport, and the axonal transport rate (ATR) was significantly lower in these rats than in control rats (P < 0.001). The levels of cytoplasmic dynein and kinesin-1 were significantly decreased in the PHA group than in the control group (P < 0.001); additionally, the levels of energy-related proteins, including cytochrome c oxidase (COX) IV and ATP synthase subunit beta (ATPB), were lower in the PHA group (P < 0.001). The brains of heroin-exposed rats displayed an abnormal ultrastructure, with neuronal apoptosis and mitochondrial dysfunction. Heroin exposure decreased the expression of NF-H, as indicated by significantly reduced staining intensities in tissues from HA and PHA rats (P < 0.05). MEMRI detected axonal transport dysfunction caused by long-term repeated exposure to heroin. The main causes of axonal transport impairment may be decreases in the levels of motor proteins and mitochondrial dysfunction. This study shows that MEMRI is a potential tool for visualizing axonal transport in individuals with drug addictions, providing a new way to evaluate addictive encephalopathy.
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Terry AV, Beck WD, Lin PC, Callahan PM, Rudic RD, Hamrick MW. Manganese-enhanced magnetic resonance imaging method detects age-related impairments in axonal transport in mice and attenuation of the impairments by a microtubule-stabilizing compound. Brain Res 2022; 1789:147947. [PMID: 35597325 DOI: 10.1016/j.brainres.2022.147947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 04/18/2022] [Accepted: 05/15/2022] [Indexed: 11/02/2022]
Abstract
In this study a manganese-enhanced magnetic resonance imaging (MEMRI) method was developed for mice for measuring axonal transport (AXT) rates in real time in olfactory receptor neurons, which project from the olfactory epithelium to the olfactory neuronal layer of the olfactory bulb. Using this MEMRI method, two major experiments were conducted: 1) an evaluation of the effects of age on AXT rates and 2) an evaluation of the brain-penetrant, microtubule-stabilizing agent, Epothilone D for effect on AXT rates in aged mice. In these studies, we improved upon previous MEMRI approaches to develop a method where real-time measurements (32 time points) of AXT rates in mice can be determined over a single (approximately 100 min) scanning session. In the age comparisons, AXT rates were significantly higher in young (mean age ∼4.0 months old) versus aged (mean age ∼24.5 months old) mice. Moreover, in aged mice, eight weeks of treatment with Epothilone D, (0.3 and 1.0 mg/kg) was associated with statistically significant increases in AXT rates compared to vehicle-treated subjects. These experiments conducted in a living mammalian model (i.e., wild type, C57BL/6 mice), using a new modified MEMRI method, thus provide further evidence that the process of aging leads to decreases in AXT rates in the brain and they further support the argument that microtubule-based therapeutic strategies designed to improve AXT rates have potential for age-related neurological disorders.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States.
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States
| | - Ping-Chang Lin
- Research Computing Center, University of Chicago, Chicago, IL 60637, United States
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States
| | - R Daniel Rudic
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States
| | - Mark W Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States
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Ribeiro AC, Hawkins E, Jahr FM, McClay JL, Deshpande LS. Repeated exposure to chlorpyrifos is associated with a dose-dependent chronic neurobehavioral deficit in adult rats. Neurotoxicology 2022; 90:172-183. [DOI: 10.1016/j.neuro.2022.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/16/2022] [Accepted: 03/25/2022] [Indexed: 11/16/2022]
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Hayes K, Megson D, Doyle A, O'Sullivan G. Occupational risk of organophosphates and other chemical and radiative exposure in the aircraft cabin: A systematic review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 796:148742. [PMID: 34375198 DOI: 10.1016/j.scitotenv.2021.148742] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/21/2021] [Accepted: 06/25/2021] [Indexed: 06/13/2023]
Abstract
Occupational exposure to oil fumes, organophosphates, halogenated flame retardants, and other volatile and semi-volatile contaminants is a concern within the aviation industry. There is no current consensus on the risk attributed to exposure to these chemical classes within the aircraft cabin. Contaminant concentrations rarely exceed conventional air quality guidelines, but concerns have been raised about these guidelines' applicability within the aircraft environment. This systematic review, the largest and most comprehensive completed to date on the subject matter, aims to synthesize the existing research related to chemical and other exposures inside the aircraft cabin to determine the occupational risk that may be attributed said exposure, as well as, determine knowledge gaps in source, pathway, and receptor that may exist. The Science Direct, Scopus, and Web of Science databases were queried with five search terms generating 138 manuscripts that met acceptance criteria and screening. Several potential areas requiring future examination were identified: Potable water on aircraft should be examined as a potential source of pollutant exposure, as should air conditioning expansion turbines. Historical exposure should also be more fully explored, and non-targeted analysis could provide valuable information to comprehend the aircraft cabin exposome. Occupational risk under typical flight scenarios appears to be limited for most healthy individuals. Contaminants of concern were demonstrated to be extant within the cabin, however the concentrations under normal circumstances do not appear to be individually responsible for the symptomologies that are present in impacted individuals. Questions remain regarding those that are more vulnerable or susceptible to exposure. Additionally, establishing the effects of chronic low dose exposure and exposure to contaminant mixtures has not been satisfied. The risk of acute exposure in mitigable fume events is substantial, and technological solutions or the replacement of compounds of concern for safer alternatives should be a priority.
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Affiliation(s)
- Kevin Hayes
- Manchester Metropolitan University, Department of Natural Sciences, Chester Street, Manchester M1 5GD, UK; Mount Royal University, Department of Earth & Environmental Science, Calgary, Alberta T3E 6K6, Canada.
| | - David Megson
- Manchester Metropolitan University, Department of Natural Sciences, Chester Street, Manchester M1 5GD, UK
| | - Aidan Doyle
- Manchester Metropolitan University, Department of Natural Sciences, Chester Street, Manchester M1 5GD, UK
| | - Gwen O'Sullivan
- Mount Royal University, Department of Earth & Environmental Science, Calgary, Alberta T3E 6K6, Canada
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Hernandez-Toledano D, Vega L. The cytoskeleton as a non-cholinergic target of organophosphate compounds. Chem Biol Interact 2021; 346:109578. [PMID: 34265256 DOI: 10.1016/j.cbi.2021.109578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/19/2021] [Accepted: 07/12/2021] [Indexed: 12/29/2022]
Abstract
Current organophosphate (OP) toxicity research now considers potential non-cholinergic mechanisms for these compounds, since the inhibition of acetylcholinesterase (AChE) cannot completely explain all the adverse biological effects of OP. Thanks to the development of new strategies for OP detection, some potential molecular targets have been identified. Among these molecules are several cytoskeletal proteins, including actin, tubulin, intermediate filament proteins, and associated proteins, such as motor proteins, microtubule-associated proteins (MAPs), and cofilin. in vitro, ex vivo, and some in vivo reports have identified alterations in the cytoskeleton following OP exposure, including cell morphology defects, cells detachments, intracellular transport disruption, aberrant mitotic spindle formation, modification of cell motility, and reduced phagocytic capability, which implicate the cytoskeleton in OP toxicity. Here, we reviewed the evidence indicating the cytoskeletal targets of OP compounds, including their strategies, the potential effects of their alterations, and their possible participation in neurotoxicity, embryonic development, cell division, and immunotoxicity related to OP compounds exposure.
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Affiliation(s)
- David Hernandez-Toledano
- Department of Toxicology, Center for Research and Advanced Studies of the National Polytechnic Institute. Av. IPN 2508, San Pedro Zacatenco, C.P. 07360, Mexico City, Mexico
| | - Libia Vega
- Department of Toxicology, Center for Research and Advanced Studies of the National Polytechnic Institute. Av. IPN 2508, San Pedro Zacatenco, C.P. 07360, Mexico City, Mexico.
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10
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Ribeiro ACR, Deshpande LS. A review of pre-clinical models for Gulf War Illness. Pharmacol Ther 2021; 228:107936. [PMID: 34171340 DOI: 10.1016/j.pharmthera.2021.107936] [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: 04/01/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 02/08/2023]
Abstract
Gulf War Illness (GWI) is a chronic multisymptomatic disorder that afflicts over 1/3rd of the 1991 GW veterans. It spans multiple bodily systems and presents itself as a syndrome exhibiting diverse symptoms including fatigue, depression, mood, and memory and concentration deficits, musculoskeletal pain and gastrointestinal distress in GW veterans. The etiology of GWI is complex and many factors, including chemical, physiological, and environmental stressors present in the GW arena, have been implicated for its development. It has been over 30 years since the end of the GW but, GWI has been persistent in suffering veterans who are also dealing with paucity of effective treatments. The multifactorial aspect of GWI along with genetic heterogeneity and lack of available data surrounding war-time exposures have proved to be challenging in developing pre-clinical models of GWI. Despite this, over a dozen GWI animal models exist in the literature. In this article, following a brief discussion of GW history, GWI definitions, and probable causes for its pathogenesis, we will expand upon various experimental models used in GWI laboratory research. These animal models will be discussed in the context of their attempts at mimicking GW-related exposures with regards to the variations in chemical combinations, doses, and frequency of exposures. We will discuss their advantages and limitations in modeling GWI followed by a discussion of behavioral and molecular findings in these models. The mechanistic data obtained from these preclinical studies have offered multiple molecular pathways including chronic inflammation, mitochondrial dysfunction, oxidative stress, lipid disturbances, calcium homeostatic alterations, changes in gut microbiota, and epigenetic modifications, amongst others for explaining GWI development and its persistence. Finally, these findings have also informed us on novel druggable targets in GWI. While, it has been difficult to conceive a single pre-clinical model that could express all the GWI signs and exhibit biological complexity reflective of the clinical presentation in GWI, animal models have been critical for identifying molecular underpinnings of GWI and evaluating treatment strategies for GWI.
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Affiliation(s)
- Ana C R Ribeiro
- Departments of Neurology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Laxmikant S Deshpande
- Departments of Neurology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA; Departments of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA.
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11
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Naughton SX, Beck WD, Wei Z, Wu G, Baas PW, Terry AV. The Carbamate, Physostigmine does not Impair Axonal Transport in Rat Cortical Neurons. Neurosci Insights 2021; 16:26331055211020289. [PMID: 34104889 PMCID: PMC8155748 DOI: 10.1177/26331055211020289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/07/2021] [Indexed: 11/21/2022] Open
Abstract
Among the various chemicals that are commonly used as pesticides,
organophosphates (OPs), and to a lesser extent, carbamates, are most frequently
associated with adverse long-term neurological consequences. OPs and the
carbamate, pyridostigmine, used as a prophylactic drug against potential nerve
agent attacks, have also been implicated in Gulf War Illness (GWI), which is
often characterized by chronic neurological symptoms. While most OP- and
carbamate-based pesticides, and pyridostigmine are relatively potent
acetylcholinesterase inhibitors (AChEIs), this toxicological mechanism is
inadequate to explain their long-term health effects, especially when no signs
of acute cholinergic toxicity are exhibited. Our previous work suggests that a
potential mechanism of the long-term neurological deficits associated with OPs
is impairment of axonal transport (AXT); however, we had not previously
evaluated carbamates for this effect. Here we thus evaluated the carbamate,
physostigmine (PHY), a highly potent AChEI, on AXT using an in
vitro neuronal live imaging assay that we have previously found to
be very sensitive to OP-related deficits in AXT. We first evaluated the OP,
diisopropylfluorophosphate (DFP) (concentration range 0.001-10.0 µM) as a
reference compound that we found previously to impair AXT and subsequently
evaluated PHY (concentration range 0.01-100 nM). As expected, DFP impaired AXT
in a concentration-dependent manner, replicating our previously published
results. In contrast, none of the concentrations of PHY (including
concentrations well above the threshold for impairing AChE) impaired AXT. These
data suggest that the long-term neurological deficits associated with some
carbamates are not likely due to acute impairments of AXT.
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Affiliation(s)
- Sean X Naughton
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, PA, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
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Sex-Based Differences in Plasma Autoantibodies to Central Nervous System Proteins in Gulf War Veterans versus Healthy and Symptomatic Controls. Brain Sci 2021; 11:brainsci11020148. [PMID: 33498629 PMCID: PMC7911379 DOI: 10.3390/brainsci11020148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/08/2021] [Accepted: 01/20/2021] [Indexed: 02/07/2023] Open
Abstract
Veterans from the 1991 Gulf War (GW) have suffered from Gulf War illness (GWI) for nearly 30 years. This illness encompasses multiple body systems, including the central nervous system (CNS). Diagnosis and treatment of GWI is difficult because there has not been an objective diagnostic biomarker. Recently, we reported on a newly developed blood biomarker that discriminates GWI from GW healthy controls, and symptomatic controls with irritable bowel syndrome (IBS) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The present study was designed to compare levels of these biomarkers between men and women with GWI, as well as sex-specific effects in comparison to healthy GW veterans and symptomatic controls (IBS, ME/CFS). The results showed that men and women with GWI differ in 2 of 10 plasma autoantibodies, with men showing significantly elevated levels. Men and women with GWI showed significantly different levels of autoantibodies in 8 of 10 biomarkers to neuronal and glial proteins in plasma relative to controls. In summary, the present study addressed the utility of the use of plasma autoantibodies for CNS proteins to distinguish among both men and women veterans with GWI and other healthy and symptomatic control groups.
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Aroniadou-Anderjaska V, Apland JP, Figueiredo TH, De Araujo Furtado M, Braga MF. Acetylcholinesterase inhibitors (nerve agents) as weapons of mass destruction: History, mechanisms of action, and medical countermeasures. Neuropharmacology 2020; 181:108298. [DOI: 10.1016/j.neuropharm.2020.108298] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/21/2020] [Accepted: 09/02/2020] [Indexed: 02/07/2023]
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Dickey B, Madhu LN, Shetty AK. Gulf War Illness: Mechanisms Underlying Brain Dysfunction and Promising Therapeutic Strategies. Pharmacol Ther 2020; 220:107716. [PMID: 33164782 DOI: 10.1016/j.pharmthera.2020.107716] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/19/2020] [Indexed: 12/13/2022]
Abstract
Gulf War Illness (GWI), a chronic multisymptom health problem, afflicts ~30% of veterans served in the first GW. Impaired brain function is among the most significant symptoms of GWI, which is typified by persistent cognitive and mood impairments, concentration problems, headaches, chronic fatigue, and musculoskeletal pain. This review aims to discuss findings from animal prototypes and veterans with GWI on mechanisms underlying its pathophysiology and emerging therapeutic strategies for alleviating brain dysfunction in GWI. Animal model studies have linked brain impairments to incessantly elevated oxidative stress, chronic inflammation, inhibitory interneuron loss, altered lipid metabolism and peroxisomes, mitochondrial dysfunction, modified expression of genes relevant to cognitive function, and waned hippocampal neurogenesis. Furthermore, the involvement of systemic alterations such as the increased intensity of reactive oxygen species and proinflammatory cytokines in the blood, transformed gut microbiome, and activation of the adaptive immune response have received consideration. Investigations in veterans have suggested that brain dysfunction in GWI is linked to chronic activation of the executive control network, impaired functional connectivity, altered blood flow, persistent inflammation, and changes in miRNA levels. Lack of protective alleles from Class II HLA genes, the altered concentration of phospholipid species and proinflammatory factors in the circulating blood have also been suggested as other aiding factors. While some drugs or combination therapies have shown promise for alleviating symptoms in clinical trials, larger double-blind, placebo-controlled trials are needed to validate such findings. Based on improvements seen in animal models of GWI, several antioxidants and anti-inflammatory compounds are currently being tested in clinical trials. However, reliable blood biomarkers that facilitate an appropriate screening of veterans for brain pathology need to be discovered. A liquid biopsy approach involving analysis of brain-derived extracellular vesicles in the blood appears efficient for discerning the extent of neuropathology both before and during clinical trials.
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Affiliation(s)
- Brandon Dickey
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center College of Medicine, College Station, TX, USA; Texas A&M University Health Science Center College of Medicine, Temple, TX, USA
| | - Leelavathi N Madhu
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center College of Medicine, College Station, TX, USA
| | - Ashok K Shetty
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center College of Medicine, College Station, TX, USA.
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Alterations in high-order diffusion imaging in veterans with Gulf War Illness is associated with chemical weapons exposure and mild traumatic brain injury. Brain Behav Immun 2020; 89:281-290. [PMID: 32745586 PMCID: PMC7755296 DOI: 10.1016/j.bbi.2020.07.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/11/2020] [Accepted: 07/08/2020] [Indexed: 01/02/2023] Open
Abstract
The complex etiology behind Gulf War Illness (GWI) has been attributed to the combined exposure to neurotoxicant chemicals, brain injuries, and some combat experiences. Chronic GWI symptoms have been shown to be associated with intensified neuroinflammatory responses in animal and human studies. To investigate the neuroinflammatory responses and potential causes in Gulf War (GW) veterans, we focused on the effects of chemical/biological weapons (CBW) exposure and mild traumatic brain injury (mTBI) during the war. We applied a novel MRI diffusion processing method, Neurite density imaging (NDI), on high-order diffusion imaging to estimate microstructural alterations of brain imaging in Gulf War veterans with and without GWI, and collected plasma proinflammatory cytokine samples as well as self-reported health symptom scores. Our study identified microstructural changes specific to GWI in the frontal and limbic regions due to CBW and mTBI, and further showed distinctive microstructural patterns such that widespread changes were associated with CBW and more focal changes on diffusion imaging were observed in GW veterans with an mTBI during the war. In addition, microstructural alterations on brain imaging correlated with upregulated blood proinflammatory cytokine markers TNFRI and TNFRII and with worse outcomes on self-reported symptom measures for fatigue and sleep functioning. Taken together, these results suggest TNF signaling mediated inflammation affects frontal and limbic regions of the brain, which may contribute to the fatigue and sleep symptoms of the disease and suggest a strong neuroinflammatory component to GWI. These results also suggest exposures to chemical weapons and mTBI during the war are associated with different patterns of peripheral and central inflammation and highlight the brain regions vulnerable to further subtle microscale morphological changes and chronic signaling to nearby glia.
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16
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Abou-Donia MB, Lapadula ES, Krengel MH, Quinn E, LeClair J, Massaro J, Conboy LA, Kokkotou E, Abreu M, Klimas NG, Nguyen DD, Sullivan K. Using Plasma Autoantibodies of Central Nervous System Proteins to Distinguish Veterans with Gulf War Illness from Healthy and Symptomatic Controls. Brain Sci 2020; 10:brainsci10090610. [PMID: 32899468 PMCID: PMC7563126 DOI: 10.3390/brainsci10090610] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 01/02/2023] Open
Abstract
For the past 30 years, there has been a lack of objective tools for diagnosing Gulf War Illness (GWI), which is largely characterized by central nervous system (CNS) symptoms emerging from 1991 Gulf War (GW) veterans. In a recent preliminary study, we reported the presence of autoantibodies against CNS proteins in the blood of veterans with GWI, suggesting a potential objective biomarker for the disorder. Now, we report the results of a larger, confirmatory study of these objective biomarkers in 171 veterans with GWI compared to 60 healthy GW veteran controls and 85 symptomatic civilian controls (n = 50 myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and n = 35 irritable bowel syndrome (IBS)). Specifically, we compared plasma markers of CNS autoantibodies for diagnostic characteristics of the four groups (GWI, GW controls, ME/CFS, IBS). For veterans with GWI, the results showed statistically increased levels of nine of the ten autoantibodies against neuronal "tubulin, neurofilament protein (NFP), Microtubule Associated Protein-2 (MAP-2), Microtubule Associated Protein-Tau (Tau), alpha synuclein (α-syn), calcium calmodulin kinase II (CaMKII)" and glial proteins "Glial Fibrillary Acidic Protein (GFAP), Myelin Associated Glycoprotein (MAG), Myelin Basic Protein (MBP), S100B" compared to healthy GW controls as well as civilians with ME/CFS and IBS. Next, we summed all of the means of the CNS autoantibodies for each group into a new index score called the Neurodegeneration Index (NDI). The NDI was calculated for each tested group and showed veterans with GWI had statistically significantly higher NDI values than all three control groups. The present study confirmed the utility of the use of plasma autoantibodies for CNS proteins to distinguish among veterans with GWI and other healthy and symptomatic control groups.
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Affiliation(s)
- Mohamed B. Abou-Donia
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA;
- Correspondence: (M.B.A.-D.); (K.S.); Tel.: +1-919-684-2221 (M.B.A.-D.)
| | - Elizabeth S. Lapadula
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA;
| | - Maxine H. Krengel
- Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA;
| | - Emily Quinn
- Departments of Biostatistics and Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA; (E.Q.); (J.L.); (J.M.); (D.D.N.)
| | - Jessica LeClair
- Departments of Biostatistics and Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA; (E.Q.); (J.L.); (J.M.); (D.D.N.)
| | - Joseph Massaro
- Departments of Biostatistics and Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA; (E.Q.); (J.L.); (J.M.); (D.D.N.)
| | - Lisa A. Conboy
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; (L.A.C.); (E.K.)
| | - Efi Kokkotou
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; (L.A.C.); (E.K.)
| | - Maria Abreu
- Dr. Kiran C. Patel College of Osteopathic Medicine, Institute for Neuroimmune Medicine, Nova Southeastern University, Fort Lauderdale, FL 33314, USA; (M.A.); (N.G.K.)
- Department of Immunology, Miami VA Medical Center, Miami, FL 33125, USA
| | - Nancy G. Klimas
- Dr. Kiran C. Patel College of Osteopathic Medicine, Institute for Neuroimmune Medicine, Nova Southeastern University, Fort Lauderdale, FL 33314, USA; (M.A.); (N.G.K.)
- Department of Immunology, Miami VA Medical Center, Miami, FL 33125, USA
| | - Daniel D. Nguyen
- Departments of Biostatistics and Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA; (E.Q.); (J.L.); (J.M.); (D.D.N.)
| | - Kimberly Sullivan
- Departments of Biostatistics and Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA; (E.Q.); (J.L.); (J.M.); (D.D.N.)
- Correspondence: (M.B.A.-D.); (K.S.); Tel.: +1-919-684-2221 (M.B.A.-D.)
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Michalovicz LT, Kelly KA, Sullivan K, O'Callaghan JP. Acetylcholinesterase inhibitor exposures as an initiating factor in the development of Gulf War Illness, a chronic neuroimmune disorder in deployed veterans. Neuropharmacology 2020; 171:108073. [PMID: 32247728 PMCID: PMC7398580 DOI: 10.1016/j.neuropharm.2020.108073] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/26/2020] [Accepted: 03/25/2020] [Indexed: 12/19/2022]
Abstract
Gulf War Illness (GWI) is a chronic multi-symptom disorder, characterized by symptoms such as fatigue, pain, cognitive and memory impairment, respiratory, skin and gastrointestinal problems, that is experienced by approximately one-third of 1991 Gulf War veterans. Over the nearly three decades since the end of the war, investigators have worked to elucidate the initiating factors and underlying causes of GWI. A significant portion of this research has indicated a strong correlation between GWI and exposure to a number of different acetycholinesterase inhibitors (AChEIs) in theater, such as sarin and cyclosarin nerve agents, chlorpyrifos and dichlorvos pesticides, and the anti-nerve agent prophylactic pyridostigmine bromide. Through studying these exposures and their relationship to the symptoms presented by ill veterans, it has become increasingly apparent that GWI is the likely result of an underlying neuroimmune disorder. While evidence indicates that AChEIs are a key exposure in the development of GWI, particularly organophosphate AChEIs, the mechanism(s) by which these chemicals instigate illness appears to be related to "off-target", non-cholinergic effects. In this review, we will discuss the role of AChEI exposure in the development and persistence of GWI; in particular, how these chemicals, combined with other exposures, have led to a chronic neuroimmune disorder. This article is part of the special issue entitled 'Acetylcholinesterase Inhibitors: From Bench to Bedside to Battlefield'.
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Affiliation(s)
- Lindsay T Michalovicz
- Health Effects Laboratory Division, Centers for Disease Control and Prevention - National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Kimberly A Kelly
- Health Effects Laboratory Division, Centers for Disease Control and Prevention - National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | | | - James P O'Callaghan
- Health Effects Laboratory Division, Centers for Disease Control and Prevention - National Institute for Occupational Safety and Health, Morgantown, WV, USA.
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Yang J, Li Q. Manganese-Enhanced Magnetic Resonance Imaging: Application in Central Nervous System Diseases. Front Neurol 2020; 11:143. [PMID: 32161572 PMCID: PMC7052353 DOI: 10.3389/fneur.2020.00143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 02/07/2020] [Indexed: 12/12/2022] Open
Abstract
Manganese-enhanced magnetic resonance imaging (MEMRI) relies on the strong paramagnetism of Mn2+. Mn2+ is a calcium ion analog and can enter excitable cells through voltage-gated calcium channels. Mn2+ can be transported along the axons of neurons via microtubule-based fast axonal transport. Based on these properties, MEMRI is used to describe neuroanatomical structures, monitor neural activity, and evaluate axonal transport rates. The application of MEMRI in preclinical animal models of central nervous system (CNS) diseases can provide more information for the study of disease mechanisms. In this article, we provide a brief review of MEMRI use in CNS diseases ranging from neurodegenerative diseases to brain injury and spinal cord injury.
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Affiliation(s)
- Jun Yang
- Department of Radiology, The Third Affiliated Hospital of Kunming Medical University, Yunnan Cancer Hospital & Cancer Center, Kunming, China
| | - Qinqing Li
- Department of Radiology, The Third Affiliated Hospital of Kunming Medical University, Yunnan Cancer Hospital & Cancer Center, Kunming, China
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19
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Multifunctional compounds lithium chloride and methylene Blue attenuate the negative effects of diisopropylfluorophosphate on axonal transport in rat cortical neurons. Toxicology 2020; 431:152379. [PMID: 31962143 DOI: 10.1016/j.tox.2020.152379] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 01/03/2020] [Accepted: 01/18/2020] [Indexed: 12/29/2022]
Abstract
Organophosphates (OPs) are valuable as pesticides in agriculture and for controlling deadly vector-borne illnesses; however, they are highly toxic and associated with many deleterious health effects in humans including long-term neurological impairments. Antidotal treatment regimens are available to combat the symptoms of acute OP toxicity, which result from the irreversible inhibition of acetylcholinesterase (AChE). However, there are no established treatments for the long-term neurological consequences of OP exposure. In addition to AChE, OPs can negatively affect multiple protein targets as well as biological processes such as axonal transport. Given the fundamental nature of axonal transport to neuronal health, we rationalized that this process might serve as a general focus area for novel therapeutic strategies against OP toxicity. In the studies described here, we employed a multi-target, phenotypic screening, and drug repurposing strategy for the evaluations of potential novel OP-treatments using a primary neuronal culture model and time-lapse live imaging microscopy. Two multi-target compounds, lithium chloride (LiCl) and methylene blue (MB), which are FDA-approved for other indications, were evaluated for their ability to prevent the negative effects of the OP, diisopropylfluorophosphate (DFP) on axonal transport. The results indicated that both LiCl and MB prevented DFP-induced impairments in anterograde and retrograde axonal transport velocities in a concentration dependent manner. While in vivo studies will be required to confirm our in vitro findings, these experiments support the potential of LiCl and MB as repurposed drugs for the treatment of the long-term neurological deficits associated with OP exposure (currently an unmet medical need).
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Brown KA, Filipov NM, Wagner JJ. Dorsoventral-Specific Effects of Nerve Agent Surrogate Diisopropylfluorophosphate on Synaptic Transmission in the Mouse Hippocampus. J Pharmacol Exp Ther 2020; 373:10-23. [DOI: 10.1124/jpet.119.263053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/16/2019] [Indexed: 11/22/2022] Open
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21
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Belgrad J, Dutta DJ, Bromley-Coolidge S, Kelly KA, Michalovicz LT, Sullivan KA, O'Callaghan JP, Fields RD. Oligodendrocyte involvement in Gulf War Illness. Glia 2019; 67:2107-2124. [PMID: 31339622 PMCID: PMC6899710 DOI: 10.1002/glia.23668] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 06/05/2019] [Accepted: 06/14/2019] [Indexed: 11/25/2022]
Abstract
Low level sarin nerve gas and other anti‐cholinesterase agents have been implicated in Gulf War illness (GWI), a chronic multi‐symptom disorder characterized by cognitive, pain and fatigue symptoms that continues to afflict roughly 32% of veterans from the 1990–1991 Gulf War. How disrupting cholinergic synaptic transmission could produce chronic illness is unclear, but recent research indicates that acetylcholine also mediates communication between axons and oligodendrocytes. Here we investigated the hypothesis that oligodendrocyte development is disrupted by Gulf War agents, by experiments using the sarin‐surrogate acetylcholinesterase inhibitor, diisopropyl fluorophosphate (DFP). The effects of corticosterone, which is used in some GWI animal models, were also investigated. The data show that DFP decreased both the number of mature and dividing oligodendrocytes in the rat prefrontal cortex (PFC), but differences were found between PFC and corpus callosum. The differences seen between the PFC and corpus callosum likely reflect the higher percentage of proliferating oligodendroglia in the adult PFC. In cell culture, DFP also decreased oligodendrocyte survival through a non‐cholinergic mechanism. Corticosterone promoted maturation of oligodendrocytes, and when used in combination with DFP it had protective effects by increasing the pool of mature oligodendrocytes and decreasing proliferation. Cell culture studies indicate direct effects of both DFP and corticosterone on OPCs, and by comparison with in vivo results, we conclude that in addition to direct effects, systemic effects and interruption of neuron–glia interactions contribute to the detrimental effects of GW agents on oligodendrocytes. Our results demonstrate that oligodendrocytes are an important component of the pathophysiology of GWI.
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Affiliation(s)
- Jillian Belgrad
- Section on Nervous System Development and Plasticity, The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland
| | - Dipankar J Dutta
- Section on Nervous System Development and Plasticity, The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland
| | - Samantha Bromley-Coolidge
- Section on Nervous System Development and Plasticity, The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland
| | - Kimberly A Kelly
- Centers for Disease Control and Prevention, Morgantown, West Virginia
| | | | - Kimberly A Sullivan
- Department of Environmental Health, Boston University School of Public Health, Boston, Massachusetts
| | | | - Richard Douglas Fields
- Section on Nervous System Development and Plasticity, The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland
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22
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Naughton SX, Terry AV. Neurotoxicity in acute and repeated organophosphate exposure. Toxicology 2018; 408:101-112. [PMID: 30144465 DOI: 10.1016/j.tox.2018.08.011] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 08/03/2018] [Accepted: 08/21/2018] [Indexed: 01/28/2023]
Abstract
The term organophosphate (OP) refers to a diverse group of chemicals that are found in hundreds of products worldwide. As pesticides, their most common use, OPs are clearly beneficial for agricultural productivity and the control of deadly vector-borne illnesses. However, as a consequence of their widespread use, OPs are now among the most common synthetic chemicals detected in the environment as well as in animal and human tissues. This is an increasing environmental concern because many OPs are highly toxic and both accidental and intentional exposures to OPs resulting in deleterious health effects have been documented for decades. Some of these deleterious health effects include a variety of long-term neurological and psychiatric disturbances including impairments in attention, memory, and other domains of cognition. Moreover, some chronic illnesses that manifest these symptoms such as Gulf War Illness and Aerotoxic Syndrome have (at least in part) been attributed to OP exposure. In addition to acute acetylcholinesterase inhibition, OPs may affect a number of additional targets that lead to oxidative stress, axonal transport deficits, neuroinflammation, and autoimmunity. Some of these targets could be exploited for therapeutic purposes. The purpose of this review is thus to: 1) describe the important uses of organophosphate (OP)-based compounds worldwide, 2) provide an overview of the various risks and toxicology associated with OP exposure, particularly long-term neurologic and psychiatric symptoms, 3) discuss mechanisms of OP toxicity beyond cholinesterase inhibition, 4) review potential therapeutic strategies to reverse the acute toxicity and long term deleterious effects of OPs.
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Affiliation(s)
- Sean X Naughton
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia.
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