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Grout MM, Mitchell KB. Disulfiram-Mitigating Unintended Effects. Antibiotics (Basel) 2023; 12:antibiotics12020262. [PMID: 36830172 PMCID: PMC9952438 DOI: 10.3390/antibiotics12020262] [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: 11/20/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 02/03/2023] Open
Abstract
Lyme disease caused by infection with a multitude of vector-borne organisms can sometimes be successfully treated in its very early stages. However, if diagnosis is delayed, this infection can become disseminated and, like another spirochetal infection syphilis, can affect multiple organ systems in the body, causing a wide variety of life-altering symptoms. Conventional antibiotic therapy may not be effective in eradicating the symptoms of the disease we know as Lyme disease. The recent literature has suggested that disulfiram (DSM) may be a potent drug in the armamentarium of physicians who treat chronic Lyme disease. The use of disulfiram in the treatment of Lyme disease started with a researcher who determined that DSM is bactericidal to spirochete. Encouraged by published case reports of apparent recovery from chronic Lyme disease, having prescribed DSM ourselves in the past for alcoholics who had a desire to stop drinking and prescribing it now for patients with chronic Lyme disease, we observed both predictable and potentially avoidable side effects not necessarily related to the ingestion of alcohol. We reviewed the published literature in PubMed and Google Scholar, using the following key words: Lyme Disease; Borrelia burgdorferi treatment; and disulfiram toxicity. This paper outlines the results of that research to help avoid some of the pitfalls inherent in this novel use of an old and established medication in the practice of clinical medicine.
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Affiliation(s)
- Martha M. Grout
- Arizona Center for Advanced Medicine, Scottsdale, AZ 85258, USA
- Correspondence: ; Tel.: +1-480-240-2600
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Almeida-Silva J, Menezes DS, Fernandes JMP, Almeida MC, Vasco-Dos-Santos DR, Saraiva RM, Viçosa AL, Perez SAC, Andrade SG, Suarez-Fontes AM, Vannier-Santos MA. The repositioned drugs disulfiram/diethyldithiocarbamate combined to benznidazole: Searching for Chagas disease selective therapy, preventing toxicity and drug resistance. Front Cell Infect Microbiol 2022; 12:926699. [PMID: 35967878 PMCID: PMC9372510 DOI: 10.3389/fcimb.2022.926699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/27/2022] [Indexed: 12/20/2022] Open
Abstract
Chagas disease (CD) affects at least 6 million people in 21 South American countries besides several thousand in other nations all over the world. It is estimated that at least 14,000 people die every year of CD. Since vaccines are not available, chemotherapy remains of pivotal relevance. About 30% of the treated patients cannot complete the therapy because of severe adverse reactions. Thus, the search for novel drugs is required. Here we tested the benznidazole (BZ) combination with the repositioned drug disulfiram (DSF) and its derivative diethyldithiocarbamate (DETC) upon Trypanosoma cruzi in vitro and in vivo. DETC-BZ combination was synergistic diminishing epimastigote proliferation and enhancing selective indexes up to over 10-fold. DETC was effective upon amastigotes of the BZ- partially resistant Y and the BZ-resistant Colombiana strains. The combination reduced proliferation even using low concentrations (e.g., 2.5 µM). Scanning electron microscopy revealed membrane discontinuities and cell body volume reduction. Transmission electron microscopy revealed remarkable enlargement of endoplasmic reticulum cisternae besides, dilated mitochondria with decreased electron density and disorganized kinetoplast DNA. At advanced stages, the cytoplasm vacuolation apparently impaired compartmentation. The fluorescent probe H2-DCFDA indicates the increased production of reactive oxygen species associated with enhanced lipid peroxidation in parasites incubated with DETC. The biochemical measurement indicates the downmodulation of thiol expression. DETC inhibited superoxide dismutase activity on parasites was more pronounced than in infected mice. In order to approach the DETC effects on intracellular infection, peritoneal macrophages were infected with Colombiana trypomastigotes. DETC addition diminished parasite numbers and the DETC-BZ combination was effective, despite the low concentrations used. In the murine infection, the combination significantly enhanced animal survival, decreasing parasitemia over BZ. Histopathology revealed that low doses of BZ-treated animals presented myocardial amastigote, not observed in combination-treated animals. The picrosirius collagen staining showed reduced myocardial fibrosis. Aminotransferase de aspartate, Aminotransferase de alanine, Creatine kinase, and urea plasma levels demonstrated that the combination was non-toxic. As DSF and DETC can reduce the toxicity of other drugs and resistance phenotypes, such a combination may be safe and effective.
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Affiliation(s)
- Juliana Almeida-Silva
- Innovations in Therapies, Education and Bioproducts Laboratory, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Diego Silva Menezes
- Parasite Biology Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Salvador, BA, Brazil
| | - Juan Mateus Pereira Fernandes
- Innovations in Therapies, Education and Bioproducts Laboratory, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Márcio Cerqueira Almeida
- Parasite Biology Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Salvador, BA, Brazil
| | - Deyvison Rhuan Vasco-Dos-Santos
- Innovations in Therapies, Education and Bioproducts Laboratory, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Roberto Magalhães Saraiva
- Laboratory of Clinical Research on Chagas Disease, Evandro Chagas Infectious Disease Institute, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Alessandra Lifsitch Viçosa
- Experimental Pharmacotechnics Laboratory, Department of Galenic Innovation, Institute of Drug Technology - Farmanguinhos, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Sandra Aurora Chavez Perez
- Project Management Technical Assistance, Institute of Drug Technology - Farmanguinhos, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Sônia Gumes Andrade
- Experimental Chagas Disease Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Salvador, BA, Brazil
| | - Ana Márcia Suarez-Fontes
- Innovations in Therapies, Education and Bioproducts Laboratory, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Marcos André Vannier-Santos
- Innovations in Therapies, Education and Bioproducts Laboratory, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
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Mirzayanov II, Garifzyanov AR, Islamov DR, Shtyrlin VG. Synthesis and Crystal Structure of Dipotassium Salts of N-Alkyl-N-{[O-alkoxy(hydroxy)phosphoryl]methyl}ditiocarbamic Acids. RUSS J GEN CHEM+ 2020. [DOI: 10.1134/s1070363220030081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Abstract
Toxic peripheral neuropathies are an important form of acquired polyneuropathy produced by a variety of xenobiotics and different exposure scenarios. Delineating the mechanisms of neurotoxicants and determining the degenerative biological pathways triggered by peripheral neurotoxicants will facilitate the development of sensitive and specific biochemical-based methods for identifying neurotoxicants, designing therapeutic interventions, and developing structure-activity relationships for predicting potential neurotoxicants. This review presents an overview of the general concepts of toxic peripheral neuropathies with the goal of providing insight into why certain agents target the peripheral nervous system and produce their associated lesions. Experimental data and the main hypotheses for the mechanisms of selected agents that produce neuronopathies, axonopathies, or myelinopathies including covalent or noncovalent modifications, compromised energy or protein biosynthesis, and oxidative injury and disruption of ionic gradients across membranes are presented. The relevance of signaling between the main components of peripheral nerve, that is, glia, neuronal perikaryon, and axon, as a target for neurotoxicants and the contribution of active programmed degenerative pathways to the lesions observed in toxic peripheral neuropathies is also discussed.
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Nunes EA, Manieri TM, Matias AC, Bertuchi FR, da Silva DA, Lago L, Sato RH, Cerchiaro G. Protective effects of neocuproine copper chelator against oxidative damage in NSC34 cells. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 836:62-71. [DOI: 10.1016/j.mrgentox.2018.06.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 06/23/2018] [Accepted: 06/25/2018] [Indexed: 11/28/2022]
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Use of Glycosyl Dithiocarbamates: Small Molecule ‘Turn-on’ Fluorescent Probe for Carbohydrate Binding Proteins. ChemistrySelect 2018. [DOI: 10.1002/slct.201702683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Dennis KE, Valentine WM. Ziram and sodium N,N-dimethyldithiocarbamate inhibit ubiquitin activation through intracellular metal transport and increased oxidative stress in HEK293 cells. Chem Res Toxicol 2015; 28:682-90. [PMID: 25714994 PMCID: PMC4406076 DOI: 10.1021/tx500450x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
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Ubiquitin activating enzyme E1 plays
a pivotal role in ubiquitin
based protein signaling through regulating the initiating step of
the cascade. Previous studies demonstrated that E1 is inhibited by
covalent modification of reactive cysteines contained within the ubiquitin-binding
groove and by conditions that increase oxidative stress and deplete
cellular antioxidants. In this study, we determined the relative contribution
of covalent adduction and oxidative stress to E1 inhibition produced
by ziram and sodium N,N-dimethyldithiocarbamate
(DMDC) in HEK293 cells. Although no dithiocarbamate-derived E1 adducts
were identified on E1 using shotgun LC/MS/MS for either ziram or DMDC,
both dithiocarbamates significantly decreased E1 activity, with ziram
demonstrating greater potency. Ziram increased intracellular levels
of zinc and copper, DMDC increased intracellular levels of only copper,
and both dithiocarbamates enhanced oxidative injury evidenced by elevated
levels of protein carbonyls and expression of heme oxygenase-1. To
assess the contribution of intracellular copper transport to E1 inhibition,
coincubations were performed with the copper chelator triethylenetetramine
hydrochloride (TET). TET significantly protected E1 activity for both
of the dithiocarbamates and decreased the associated oxidative injury
in HEK293 cells as well as prevented dithiocarbamate-mediated lipid
peroxidation assayed using an ethyl aracidonate micelle system. Because
TET did not completely ameliorate intracellular transport of copper
or zinc for ziram, TET apparently maintained E1 activity through its
ability to diminish dithiocarbamate-mediated oxidative stress. Experiments
to determine the relative contribution of elevated intracellular zinc
and copper were performed using a metal free incubation system and
showed that increases in either metal were sufficient to inhibit E1.
To evaluate the utility of the HEK293 in vitro system for screening
environmental agents, a series of additional pesticides and metals
was assayed, and eight agents that produced a significant decrease
and five that produced a significant increase in activated E1 were
identified. These studies suggest that E1 is a sensitive redox sensor
that can be modulated by exposure to environmental agents and can
regulate downstream cellular processes.
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Affiliation(s)
- Kathleen E Dennis
- †Department of Pathology, Microbiology and Immunology, ‡Center in Molecular Toxicology, §Vanderbilt Brain Institute, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, Tennessee 37232-2561, United States
| | - William M Valentine
- †Department of Pathology, Microbiology and Immunology, ‡Center in Molecular Toxicology, §Vanderbilt Brain Institute, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, Tennessee 37232-2561, United States
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Carmona A, Roudeau S, Perrin L, Veronesi G, Ortega R. Environmental manganese compounds accumulate as Mn(ii) within the Golgi apparatus of dopamine cells: relationship between speciation, subcellular distribution, and cytotoxicity. Metallomics 2014; 6:822-32. [DOI: 10.1039/c4mt00012a] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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9
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Caito SW, Valentine WM, Aschner M. Dopaminergic neurotoxicity of S-ethyl N,N-dipropylthiocarbamate (EPTC), molinate, and S-methyl-N,N-diethylthiocarbamate (MeDETC) in Caenorhabditis elegans. J Neurochem 2013; 127:837-51. [PMID: 23786526 DOI: 10.1111/jnc.12349] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/14/2013] [Accepted: 06/17/2013] [Indexed: 12/14/2022]
Abstract
Epidemiological studies corroborate a correlation between pesticide use and Parkinson's disease (PD). Thiocarbamate and dithiocarbamate pesticides are widely used and produce neurotoxicity in the peripheral nervous system. Recent evidence from rodent studies suggests that these compounds also cause dopaminergic (DAergic) dysfunction and altered protein processing, two hallmarks of PD. However, DAergic neurotoxicity has yet to be documented. We assessed DAergic dysfunction in Caenorhabditis elegans (C. elegans) to investigate the ability of thiocarbamate pesticides to induce DAergic neurodegeneration. Acute treatment with either S-ethyl N,N-dipropylthiocarbamate (EPTC), molinate, or a common reactive intermediate of dithiocarbamate and thiocarbamate metabolism, S-methyl-N,N-diethylthiocarbamate (MeDETC), to gradual loss of DAergic cell morphology and structure over the course of 6 days in worms expressing green fluorescent protein (GFP) under a DAergic cell specific promoter. HPLC analysis revealed decreased DA content in the worms immediately following exposure to MeDETC, EPTC, and molinate. In addition, worms treated with the three test compounds showed a drastic loss of DAergic-dependent behavior over a time course similar to changes in DAergic cell morphology. Alterations in the DAergic system were specific, as loss of cell structure and neurotransmitter content was not observed in cholinergic, glutamatergic, or GABAergic systems. Overall, our data suggest that thiocarbamate pesticides promote neurodegeneration and DAergic cell dysfunction in C. elegans, and may be an environmental risk factor for PD.
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Affiliation(s)
- Samuel W Caito
- Division of Clinical Pharmacology and Pediatric Toxicology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Matias AC, Manieri TM, Cipriano SS, Carioni VM, Nomura CS, Machado CM, Cerchiaro G. Diethyldithiocarbamate induces apoptosis in neuroblastoma cells by raising the intracellular copper level, triggering cytochrome c release and caspase activation. Toxicol In Vitro 2013; 27:349-57. [DOI: 10.1016/j.tiv.2012.08.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 08/09/2012] [Accepted: 08/09/2012] [Indexed: 01/09/2023]
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11
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Rahden-Staroń I, Grosicka-Maciąg E, Kurpios-Piec D, Czeczot H, Grzela T, Szumiło M. The effects of sodium diethyldithiocarbamate in fibroblasts V79 cells in relation to cytotoxicity, antioxidative enzymes, glutathione, and apoptosis. Arch Toxicol 2012; 86:1841-50. [PMID: 22872140 PMCID: PMC3496549 DOI: 10.1007/s00204-012-0909-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 07/24/2012] [Indexed: 01/07/2023]
Abstract
Sodium diethyldithiocarbamate (DETC) is the main metabolite of disulfiram. Recently, we reported that mechanism of disulfiram cytotoxicity in V79 cells might be partially connected with thiol redox-state imbalance. Here, we examined the effect of DETC on the level of intracellular glutathione (GSH), protein oxidation (measured as PC—protein carbonyl content), lipid peroxidation (measured as TBARS—thiobarbituric acid reactive substances), antioxidant enzymatic defense, as well as on apoptosis. We used V79 Chinese hamster fibroblasts cells with and without modulated glutathione (GSH) level by N-acetyl-l-cysteine (NAC). We showed that treatment with DETC at concentrations that cause a moderate increase in thiol-state imbalance but not cell death stimulates oxidative stress measured as increased level of PC and TBARS, adaptive response of GSH-related enzymes and apoptosis. Our results show that cellular effects of DETC are partially attributable to the initial redox cellular state, since the increase of GSH level by NAC pre-treatment prevented the observed changes.
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Affiliation(s)
- I Rahden-Staroń
- Department of Biochemistry, Medical University of Warsaw, Banacha 1, 02-097, Warsaw, Poland.
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Chauhan HPS, Bakshi A, Bhatiya S. Synthesis, spectroscopic characterization and antibacterial activity of antimony(III) bis(dialkyldithiocarbamato)alkyldithiocarbonates. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 81:417-423. [PMID: 21764366 DOI: 10.1016/j.saa.2011.06.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 06/07/2011] [Accepted: 06/16/2011] [Indexed: 05/31/2023]
Abstract
Some mixed sulfur donor ligand complexes of antimony(III) of the general formula [(R(2)NCS(2))](2)SbS(2)COR' where R = CH(3), C(2)H(5) and R' = Me, Et, Pr(n), Pr(i), Bu(n) and Bu(i) have been synthesized by the reaction of antimony(III) bis(dialkyldithiocarbamate) chloride with potassium organodithiocarbonate in an equimolar ratio by stirring at room temperature in benzene/CS(2) mixture. These complexes have been characterized by physicochemical [elemental analysis, melting points and molecular weight determinations] and spectral [UV, IR, Far-IR, NMR ((1)H and (13)C), FAB(+) mass and powder X-ray diffraction] studies. Free ligands and synthesized complexes have also been screened against different bacterial strains and results obtained made it desirable to delineate a comparison between free ligands, standard drug used and synthesized complexes.
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Affiliation(s)
- H P S Chauhan
- School of Chemical Sciences, Devi Ahilya University, Takshashila Campus, Khandwa Road, Indore 452001, India.
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Braconi D, Bernardini G, Santucci A. Linking protein oxidation to environmental pollutants: redox proteomic approaches. J Proteomics 2011; 74:2324-37. [PMID: 21767673 DOI: 10.1016/j.jprot.2011.06.029] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 06/17/2011] [Accepted: 06/28/2011] [Indexed: 12/11/2022]
Abstract
Environmental pollutants, such as compounds used in agriculture or deriving from vehicles, industries and human activities, can represent major concern for human health since they are considered to contribute significantly to many diseased states with major public health significance. Besides considerable epidemiological evidence linking environmental pollutants with adverse health effects, little information is provided on the effects of these compounds at the cellular and molecular level. Though oxidative stress is generally acknowledged as one of the most important mechanisms of action for pollutant-induced toxicity, redox proteomics, the elective tool to identify post-translationally oxidized proteins, is still in its very infancy in this field of investigation. This review will provide the readers with an outline of the use of redox proteomics in evaluating pollutant-induced oxidative damage to proteins in various biological systems. Future potential applications of redox proteomic approaches from an environmental point of view will be discussed as well.
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Affiliation(s)
- Daniela Braconi
- Dipartimento di Biotecnologie, Università degli Studi di Siena, SI, Italy
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The significance of copper chelators in clinical and experimental application. J Nutr Biochem 2011; 22:301-10. [DOI: 10.1016/j.jnutbio.2010.06.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2010] [Revised: 06/08/2010] [Accepted: 06/30/2010] [Indexed: 01/17/2023]
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Valentine HL, Viquez OM, Valentine WM. Peripheral nerve and brain differ in their capacity to resolve N,N-diethyldithiocarbamate-mediated elevations in copper and oxidative injury. Toxicology 2010; 274:10-7. [PMID: 20452388 DOI: 10.1016/j.tox.2010.04.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 04/28/2010] [Accepted: 04/30/2010] [Indexed: 11/24/2022]
Abstract
Previous studies have demonstrated that N,N-diethyldithiocarbamate (DEDC) elevates copper and promotes oxidative stress within the nervous system. However, whether these effects resolve following cessation of exposure or have the potential to persist and result in cumulative injury has not been determined. In this study, an established model for DEDC myelin injury in the rat was used to determine whether copper levels, oxidative stress, and neuromuscular deficits resolve following the cessation of DEDC exposure. Rats were exposed to DEDC for 8 weeks and then either euthanized or maintained for 2, 6 or 12 weeks after cessation of exposure. At each time point copper levels were measured by inductively coupled mass spectrometry to assess the ability of sciatic nerve, brain, spinal cord and liver to eliminate excess copper post-exposure. The protein expression levels of glutathione transferase alpha, heme oxygenase 1 and superoxide dismutase 1 in peripheral nerve and brain were also determined by western blot to assess levels of oxidative stress as a function of post-exposure duration. As an initial assessment of the bioavailability of the excess copper in brain the protein expression levels of copper chaperone for superoxide dismutase 1, and prion protein were determined by western blot as a function of exposure and post-exposure duration. Neuromuscular function in peripheral nerve was evaluated using grip strengths, nerve conduction velocities, and morphologic changes at the light microscope level. The data demonstrated that in peripheral nerve, copper levels and oxidative stress return to control levels within several weeks after cessation of exposure. Neuromuscular function also showed a trend towards pre-exposure values, although the resolution of myelin lesions was more delayed. In contrast, total copper and antioxidant enzyme levels remained significantly elevated in brain for longer post-exposure periods. The persistence of effects observed in brain suggests that the central nervous system is more susceptible to long-term cumulative adverse effects from dithiocarbamates. Additionally, significant changes in expression levels of chaperone for superoxide dismutase 1, and prion protein were observed consistent with at least a portion of the excess copper being bioactive.
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Affiliation(s)
- Holly L Valentine
- Department of Pathology, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232-2561, USA
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N,N-diethyldithiocarbamate promotes oxidative stress prior to myelin structural changes and increases myelin copper content. Toxicol Appl Pharmacol 2009; 239:71-9. [PMID: 19467251 DOI: 10.1016/j.taap.2009.05.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 04/14/2009] [Accepted: 05/16/2009] [Indexed: 10/20/2022]
Abstract
Dithiocarbamates are a commercially important class of compounds that can produce peripheral neuropathy in humans and experimental animals. Previous studies have supported a requirement for copper accumulation and enhanced lipid peroxidation in dithiocarbamate-mediated myelinopathy. The study presented here extends previous investigations in two areas. Firstly, although total copper levels have been shown to increase within the nerve it has not been determined whether copper is increased within the myelin compartment, the primary site of lesion development. Therefore, the distribution of copper in sciatic nerve was characterized using synchrotron X-ray fluorescence microscopy to determine whether the neurotoxic dithiocarbamate, N,N-diethyldithiocarbamate, increases copper levels in myelin. Secondly, because lipid peroxidation is an ongoing process in normal nerve and the levels of lipid peroxidation products produced by dithiocarbamate exposure demonstrated an unusual cumulative dose response in previous studies the biological impact of dithiocarbamate-mediated lipid peroxidation was evaluated. Experiments were performed to determine whether dithiocarbamate-mediated lipid peroxidation products elicit an antioxidant response through measuring the protein expression levels of three enzymes, superoxide dismutase 1, heme oxygenase 1, and glutathione transferase alpha, that are linked to the antioxidant response element promoter. To establish the potential of oxidative injury to contribute to myelin injury the temporal relationship of the antioxidant response to myelin injury was determined. Myelin structure in peripheral nerve was assessed using multi-exponential transverse relaxation measurements (MET(2)) as a function of exposure duration, and the temporal relationship of protein expression changes relative to the onset of changes in myelin integrity were determined. Initial assessments were also performed to explore the potential contribution of dithiocarbamate-mediated inhibition of proteasome function and inhibition of cuproenzyme activity to neurotoxicity, and also to assess the potential of dithiocarbamates to promote oxidative stress and injury within the central nervous system. These evaluations were performed using an established model for dithiocarbamate-mediated demyelination in the rat utilizing sciatic nerve, spinal cord and brain samples obtained from rats exposed to N,N-diethyldithiocarbamate (DEDC) by intra-abdominal pumps for periods of 2, 4, and 8 weeks and from non exposed controls. The data supported the ability of DEDC to increase copper within myelin and to enhance oxidative stress prior to structural changes detectable by MET(2). Evidence was also obtained that the excess copper produced by DEDC in the central nervous system is redox active and promotes oxidative injury.
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