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Petroff RL, Grant KS, Burbacher TM. The Role of Nonhuman Primates in Neurotoxicology Research: Preclinical Models and Experimental Methods. Curr Protoc 2023; 3:e698. [PMID: 36912610 PMCID: PMC10084743 DOI: 10.1002/cpz1.698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Although noteworthy progress has been made in developing alternatives to animal testing, nonhuman primates still play a critical role in advancing biomedical research and will likely do so for many years. Core similarities between monkeys and humans in genetics, physiology, reproduction, development, and behavior make them excellent models for translational studies relevant to human health. This unit is designed to specifically address the role of nonhuman primates in neurotoxicology research and outlines the specialized assessments that can be used to measure exposure-related changes at the structural, chemical, cellular, molecular, and functional levels. © 2023 Wiley Periodicals LLC.
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Affiliation(s)
- Rebekah L Petroff
- Department of Environmental & Occupational Health Sciences (DEOHS), University of Washington, Seattle, Washington
| | - Kimberly S Grant
- Department of Environmental & Occupational Health Sciences (DEOHS), University of Washington, Seattle, Washington
| | - Thomas M Burbacher
- Department of Environmental & Occupational Health Sciences (DEOHS), University of Washington, Seattle, Washington
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Norris SA, White H, Tanenbaum A, Williams EL, Cruchaga C, Tian L, Schmidt RE, Perlmutter JS. Severe acute neurotoxicity reflects absolute intra-carotid 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine dose in non-human primates. J Neurosci Methods 2022; 366:109406. [PMID: 34767855 DOI: 10.1016/j.jneumeth.2021.109406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/18/2021] [Accepted: 11/02/2021] [Indexed: 11/18/2022]
Affiliation(s)
- S A Norris
- Departments of Neurology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA; Departments of Radiology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA.
| | - Hcb White
- Departments of Neurology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA
| | - A Tanenbaum
- Departments of Neurology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA
| | - E L Williams
- Departments of Neurology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA
| | - C Cruchaga
- Departments of Psychiatry, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA
| | - L Tian
- Departments of Neurology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA
| | - R E Schmidt
- Departments of Pathology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA
| | - J S Perlmutter
- Departments of Neurology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA; Departments of Radiology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA; Departments of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA; Departments of Physical, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA; Departments of Occupational Therapy, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA
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Jeong HS, Lee SR, Kim JE, Lyoo IK, Yoon S, Namgung E, Chang KT, Kim BS, Yang S, Im JJ, Jeon S, Kang I, Ma J, Chung YA, Lim SM. Brain structural changes in cynomolgus monkeys administered with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine: A longitudinal voxel-based morphometry and diffusion tensor imaging study. PLoS One 2018; 13:e0189804. [PMID: 29320500 PMCID: PMC5761839 DOI: 10.1371/journal.pone.0189804] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 12/02/2017] [Indexed: 12/28/2022] Open
Abstract
In animal models of Parkinson's disease (PD), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is one of the most widely used agents that damages the nigrostriatal dopaminergic pathway. However, brain structural changes in response to MPTP remain unclear. This study aimed to investigate in vivo longitudinal changes in gray matter (GM) volume and white matter (WM) microstructure in primate models administered with MPTP. In six cynomolgus monkeys, high-resolution magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) scans were acquired 7 times over 32 weeks, and assessments of motor symptoms were conducted over 15 months, before and after the MPTP injection. Changes in GM volume and WM microstructure were estimated on a voxel-by-voxel basis. Mixed-effects regression models were used to examine the trajectories of these structural changes. GM volume initially increased after the MPTP injection and gradually decreased in the striatum, midbrain, and other dopaminergic areas. The cerebellar volume temporarily decreased and returned to its baseline level. The rate of midbrain volume increase was positively correlated with the increase rate of motor symptom severity (Spearman rho = 0.93, p = 0.008). Mean, axial, and radial diffusivity in the striatum and frontal areas demonstrated initial increases and subsequent decreases. The current multi-modal imaging study of MPTP-administered monkeys revealed widespread and dynamic structural changes not only in the nigrostriatal pathway but also in other cortical, subcortical, and cerebellar areas. Our findings may suggest the need to further investigate the roles of inflammatory reactions and glial activation as potential underlying mechanisms of these structural changes.
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Affiliation(s)
- Hyeonseok S. Jeong
- Department of Radiology, Incheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Sang-Rae Lee
- National Primate Research Center, Korean Research Institute of Bioscience and Biotechnology, Ochang, South Korea
| | - Jieun E. Kim
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea
| | - In Kyoon Lyoo
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea
- Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, South Korea
| | - Sujung Yoon
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea
| | - Eun Namgung
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea
| | - Kyu-Tae Chang
- National Primate Research Center, Korean Research Institute of Bioscience and Biotechnology, Ochang, South Korea
| | - Bom Sahn Kim
- Department of Nuclear Medicine, Ewha Womans University Mokdong Hospital, Seoul, South Korea
| | - Sejung Yang
- Institute of Convergence Medicine, Ewha Womans University Medical Center, Seoul, South Korea
| | - Jooyeon J. Im
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea
- Interdisciplinary Program in Neuroscience, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Saerom Jeon
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea
| | - Ilhyang Kang
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea
| | - Jiyoung Ma
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea
- Interdisciplinary Program in Neuroscience, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Yong-An Chung
- Department of Radiology, Incheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Soo Mee Lim
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea
- Department of Radiology, Ewha Womans University Mokdong Hospital, Seoul, South Korea
- * E-mail:
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Magnetic resonance imaging and tensor-based morphometry in the MPTP non-human primate model of Parkinson's disease. PLoS One 2017; 12:e0180733. [PMID: 28738061 PMCID: PMC5524324 DOI: 10.1371/journal.pone.0180733] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 06/20/2017] [Indexed: 12/30/2022] Open
Abstract
Parkinson’s disease (PD) is the second most common neurodegenerative disorder producing a variety of motor and cognitive deficits with the causes remaining largely unknown. The gradual loss of the nigrostriatal pathway is currently considered the pivotal pathological event. To better understand the progression of PD and improve treatment management, defining the disease on a structural basis and expanding brain analysis to extra-nigral structures is indispensable. The anatomical complexity and the presence of neuromelanin, make the use of non-human primates an essential element in developing putative imaging biomarkers of PD. To this end, ex vivo T2-weighted magnetic resonance images were acquired from control and 1-methyl-4 phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated marmosets. Volume measurements of the caudate, putamen, and substantia nigra indicated significant atrophy and cortical thinning. Tensor-based morphometry provided a more extensive and hypothesis free assessment of widespread changes caused by the toxin insult to the brain, especially highlighting regional cortical atrophy. The results highlight the importance of developing imaging biomarkers of PD in non-human primate models considering their distinct neuroanatomy. It is essential to further develop these biomarkers in vivo to provide non-invasive tools to detect pre-symptomatic PD and to monitor potential disease altering therapeutics.
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Yun JW, Ahn JB, Kang BC. Modeling Parkinson's disease in the common marmoset (Callithrix jacchus): overview of models, methods, and animal care. Lab Anim Res 2015; 31:155-65. [PMID: 26755918 PMCID: PMC4707143 DOI: 10.5625/lar.2015.31.4.155] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 11/04/2015] [Accepted: 11/11/2015] [Indexed: 12/14/2022] Open
Abstract
The common marmoset (Callithrix jacchus) is a small-bodied, popular New World monkey and is used widely in reproductive biology, neuroscience, and drug development, due to its comparative ease of handling, high reproductive efficiency, and its unique behavioral characters. In this review, we discuss the marmoset models in Parkinson's disease (PD), which is a neurological movement disorder primarily resulting from a degeneration of dopaminergic neurons with clinical features of tremor, rigidity, postural instability, and akinesia. The most common PD models involve the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 6-hydroxydopamine to study the pathogenesis and to evaluate novel therapies. Following the systemic or local administration of these neurotoxins, the marmosets with very severe Parkinson's symptoms are recommended to be placed in an intensive care unit with artificial feeding to increase survival rate. All procedures with MPTP should be conducted in a special room with enclosed cages under negative-pressure by trained researchers with personal protection. Behavioral tests are conducted to provide an external measure of the brain pathology. Along with several biomarkers, including α-synuclein and DJ-1, non-invasive neuroimaging techniques such as positron emission tomography and magnetic resonance imaging are used to evaluate the functional changes associated with PD. With the recent growing interest in potential and novel therapies such as stem cell and gene therapy for PD in Korea, the marmoset can be considered as a suitable non-human primate model in PD research to bridge the gap between rodent studies and clinical applications.
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Affiliation(s)
- Jun-Won Yun
- Department of Experimental Animal Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Jae-Bum Ahn
- Department of Experimental Animal Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
- Graduate School of Translational Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Byeong-Cheol Kang
- Department of Experimental Animal Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
- Graduate School of Translational Medicine, Seoul National University College of Medicine, Seoul, Korea
- Designed Animal Research Center, Institute of GreenBio Science Technology, Seoul National University, Pyeongchang-gun, Gangwon, Korea
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Pienaar IS, Harrison IF, Elson JL, Bury A, Woll P, Simon AK, Dexter DT. An animal model mimicking pedunculopontine nucleus cholinergic degeneration in Parkinson's disease. Brain Struct Funct 2013; 220:479-500. [PMID: 24292256 DOI: 10.1007/s00429-013-0669-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 10/29/2013] [Indexed: 11/28/2022]
Abstract
A rostral brainstem structure, the pedunculopontine nucleus (PPN), is severely affected by Parkinson's disease (PD) pathology and is regarded a promising target for therapeutic deep-brain stimulation (DBS). However, understanding the PPN's role in PD and assessing the potential of DBS are hampered by the lack of a suitable model of PPN degeneration. Rats were rendered Parkinsonian through a unilateral substantia nigra pars compacta (SNpc) stereotaxic injection of the proteasome inhibitor Lactacystin, to investigate whether the lesion's pathological effects spread to impact the integrity of PPN cholinergic neurons which are affected in PD. At 5 weeks post-surgery, stereological analysis revealed that the lesion caused a 48 % loss of dopaminergic SNpc neurons and a 61 % loss of PPN cholinergic neurons, accompanied by substantial somatic hypotrophy in the remaining cholinergic neurons. Magnetic resonance imaging revealed T2 signal hyper-/hypointensity in the PPN of the injected hemisphere, respectively at weeks 3 and 5 post-lesion. Moreover, isolated PPN cholinergic neurons revealed no significant alterations in key autophagy mRNA levels, suggesting that autophagy-related mechanisms fail to protect the PPN against Lactacystin-induced cellular changes. Hence, the current results suggest that the Lactacystin PD model offers a suitable model for investigating the role of the PPN in PD.
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Affiliation(s)
- Ilse S Pienaar
- Division of Brain Sciences, Department of Medicine, Centre for Neuroinflammation and Neurodegeneration, Imperial College London, London, W12 ONN, UK,
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Delli Pizzi S, Rossi C, Di Matteo V, Esposito E, Guarnieri S, Mariggiò MA, Franciotti R, Caulo M, Thomas A, Onofrj M, Tartaro A, Bonanni L. Morphological and metabolic changes in the nigro-striatal pathway of synthetic proteasome inhibitor (PSI)-treated rats: a MRI and MRS study. PLoS One 2013; 8:e56501. [PMID: 23431380 PMCID: PMC3576393 DOI: 10.1371/journal.pone.0056501] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Accepted: 01/10/2013] [Indexed: 12/25/2022] Open
Abstract
Systemic administration of a Synthetic Proteasome Inhibitor (PSI) in rats has been described as able to provide a model of Parkinson's disease (PD), characterized by behavioral and biochemical modifications, including loss of dopaminergic neurons in the substantia nigra (SN), as assessed by post-mortem studies. With the present study we aimed to assess in-vivo by Magnetic Resonance (MR) possible morphological and metabolic changes in the nigro-striatal pathway of PSI-treated rats. 10 animals were subcutaneously injected with PSI 6.0 mg/kg dissolved in DMSO 100%. Injections were made thrice weekly over the course of two weeks. 5 more animals injected with DMSO 100% with the same protocol served as controls. The animals underwent MR sessions before and at four weeks after the end of treatment with either PSI or vehicle. MR Imaging was performed to measure SN volume and Proton MR Spectroscopy ((1)H-MRS) was performed to measure metabolites changes at the striatum. Animals were also assessed for motor function at baseline and at 4 and 6 weeks after treatment. Dopamine and dopamine metabolite levels were measured in the striata at 6 weeks after treatment. PSI-treated animals showed volumetric reduction of the SN (p<0.02) at 4 weeks after treatment as compared to baseline. Immunofluorescence analysis confirmed MRI changes in SN showing a reduction of tyrosine hydroxylase expression as compared to neuron-specific enolase expression. A reduction of N-acetyl-aspartate/total creatine ratio (p = 0.05) and an increase of glutamate-glutamine-γ amminobutirrate/total creatine were found at spectroscopy (p = 0.03). At 6 weeks after treatment, PSI-treated rats also showed motor dysfunction compared to baseline (p = 0.02), accompanied by dopamine level reduction in the striatum (p = 0.02). Treatment with PSI produced morphological and metabolic modifications of the nigro-striatal pathway, accompanied by motor dysfunction. MR demonstrated to be a powerful mean to assess in-vivo the nigro-striatal pathway morphology and metabolism in the PSI-based PD animal model.
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Affiliation(s)
- Stefano Delli Pizzi
- ITAB, “G. D’Annunzio University”, Chieti, Italy
- Department of Neuroscience and Imaging and CE.S.I. Aging Research Center, University G.d’Annunzio of Chieti-Pescara, Italy
| | - Cosmo Rossi
- Aging Research Center, Ce.S.I., “Gabriele d’Annunzio” University Foundation, Chieti, Italy
| | - Vincenzo Di Matteo
- Laboratory of Neurophysiology, Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mario Negri Sud, Santa Maria Imbaro (Chieti), Italy
| | - Ennio Esposito
- Laboratory of Neurophysiology, Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mario Negri Sud, Santa Maria Imbaro (Chieti), Italy
| | - Simone Guarnieri
- Department of Neuroscience and Imaging and CE.S.I. Aging Research Center, University G.d’Annunzio of Chieti-Pescara, Italy
| | - Maria Addolorata Mariggiò
- Department of Neuroscience and Imaging and CE.S.I. Aging Research Center, University G.d’Annunzio of Chieti-Pescara, Italy
| | | | - Massimo Caulo
- ITAB, “G. D’Annunzio University”, Chieti, Italy
- Department of Neuroscience and Imaging and CE.S.I. Aging Research Center, University G.d’Annunzio of Chieti-Pescara, Italy
| | - Astrid Thomas
- Department of Neuroscience and Imaging and CE.S.I. Aging Research Center, University G.d’Annunzio of Chieti-Pescara, Italy
| | - Marco Onofrj
- Department of Neuroscience and Imaging and CE.S.I. Aging Research Center, University G.d’Annunzio of Chieti-Pescara, Italy
| | - Armando Tartaro
- ITAB, “G. D’Annunzio University”, Chieti, Italy
- Department of Neuroscience and Imaging and CE.S.I. Aging Research Center, University G.d’Annunzio of Chieti-Pescara, Italy
| | - Laura Bonanni
- Department of Neuroscience and Imaging and CE.S.I. Aging Research Center, University G.d’Annunzio of Chieti-Pescara, Italy
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The interhemispheric connections of the striatum: Implications for Parkinson's disease and drug-induced dyskinesias. Brain Res Bull 2011; 87:1-9. [PMID: 21963946 DOI: 10.1016/j.brainresbull.2011.09.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 09/16/2011] [Accepted: 09/19/2011] [Indexed: 11/20/2022]
Abstract
Parkinson's disease (PD) is characterized by loss of nigrostriatal neurons and depletion of dopamine. This pathological feature leads to alterations to basal ganglia circuitry and subsequent motor disability. Pharmacological dopamine replacement therapy with medications such as levodopa ameliorates the symptoms of PD but can lead to motor complications known as drug-induced dyskinesias. We have recently shown that clinically hemiparkinsonian rhesus monkeys do not develop levodopa-induced dyskinesias despite chronic intermittent exposure and significant unilateral loss of nigrostriatal neurons and dopamine. It is currently unclear what mechanisms prevent the onset of dyskinesias in these animals. Based on our study and results from previous lesioning studies in both the rat and monkey models of PD, we hypothesize that one potential mechanism that may prevent the genesis of dyskinesias in these animals is interhemispheric neuromodulation. Two potential interhemispheric connections that may modulate dyskinesias are the interhemispheric nigrostriatal and corticostriatal pathways. Few investigators have examined the interhemispheric nigrostriatal and corticostriatal connections and the functional role they may play in drug-induced dyskinesias in PD. Therefore, in the following review, we assess the neuroanatomical, electrophysiological and behavioral properties of these interhemispheric connections. Future studies evaluating these interhemispheric striatal pathways and the pathophysiological changes that occur to these pathways in the dyskinetic state are warranted to further develop treatments that prevent or mitigate drug-induced dyskinesias in PD.
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Vernon AC, Johansson SM, Modo MM. Non-invasive evaluation of nigrostriatal neuropathology in a proteasome inhibitor rodent model of Parkinson's disease. BMC Neurosci 2010; 11:1. [PMID: 20051106 PMCID: PMC2824797 DOI: 10.1186/1471-2202-11-1] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 01/05/2010] [Indexed: 01/07/2023] Open
Abstract
Background Predominantly, magnetic resonance imaging (MRI) studies in animal models of Parkinson's disease (PD) have focused on alterations in T2 water 1H relaxation or 1H MR spectroscopy (MRS), whilst potential morphological changes and their relationship to histological or behavioural outcomes have not been appropriately addressed. Therefore, in this study we have utilised MRI to scan in vivo brains from rodents bearing a nigrostriatal lesion induced by intranigral injection of the proteasome inhibitor lactacystin. Results Lactacystin induced parkinsonian-like behaviour, characterised by impaired contralateral forelimb grip strength and increased contralateral circling in response to apomorphine. T2-weighted MRI, 3-weeks post-lesion, revealed significant morphological changes in PD-relevant brain areas, including the striatum and ventral midbrain in addition to a decrease in T2 water 1H relaxation in the substantia nigra (SN), but not the striatum. Post-mortem histological analyses revealed extensive dopaminergic neuronal degeneration and α-synuclein aggregation in the SN. However, extensive neuronal loss could also be observed in extra-nigral areas, suggesting non-specific toxicity of lactacystin. Iron accumulation could also be observed throughout the midbrain reflecting changes in T2. Importantly, morphological, but not T2 relaxivity changes, were significantly associated with both behavioural and histological outcomes in this model. Conclusions A pattern of morphological changes in lactacystin-lesioned animals has been identified, as well as alterations in nigral T2 relaxivity. The significant relationship of morphological changes with behavioural and histological outcomes in this model raises the possibility that these may be useful non-invasive surrogate markers of nigrostriatal degeneration in vivo.
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Affiliation(s)
- Anthony C Vernon
- Department of Neuroscience, Kings College London, The James Black Centre, UK
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Lee DW, Andersen JK. Iron elevations in the aging Parkinsonian brain: a consequence of impaired iron homeostasis? J Neurochem 2010; 112:332-9. [DOI: 10.1111/j.1471-4159.2009.06470.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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De Pablos V, Barcia C, Martínez S, Gomez A, Ros-Bernal F, Zamarro-Parra J, Soria-Torrecillas JJ, Hernández J, Ceron JJ, Herrero MT. MPTP administration increases plasma levels of acute phase proteins in non-human primates (Macaca fascicularis). Neurosci Lett 2009; 463:37-9. [PMID: 19638294 DOI: 10.1016/j.neulet.2009.07.069] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 07/21/2009] [Accepted: 07/23/2009] [Indexed: 11/26/2022]
Abstract
Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the Substantia Nigra pars compacta (SNpc). Parkinsonian patients and animal models of PD show inflammatory phenomena such as microglial activation and cytokine production that could modulate the progression of the disease, since they play a crucial role in the degenerative process. Since acute phase proteins (APPs) are involved in a number of homeostatic alterations and inflammatory processes, we analyzed the levels of APPs in primates before and after treatment with MPTP. A significant increase in C-reactive protein (CRP), serum amyloid A (SAA) and haptoglobin (HP) levels after MPTP treatment. These results demonstrate that MPTP induces a systemic generalized inflammatory reaction after specific dopaminergic neurotoxicity insult, suggesting that the inflammatory process in Parkinsonism may affect other immune-inflammatory responses outside the brain.
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Affiliation(s)
- V De Pablos
- Clinical and Experimental Neuroscience and Centro de Investigación Biomedica en Red de Enfermedades Neurodegenerativas (CIBERNED), School of Medicine, University of Murcia, Campus de Espinardo, 30071 Murcia, Spain
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Lagrue E, Abert B, Nadal L, Tabone L, Bodard S, Medja F, Lombes A, Chalon S, Castelnau P. MPTP intoxication in mice: a useful model of Leigh syndrome to study mitochondrial diseases in childhood. Metab Brain Dis 2009; 24:321-35. [PMID: 19319673 DOI: 10.1007/s11011-009-9132-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 10/22/2008] [Indexed: 02/02/2023]
Abstract
The basal ganglia, which are interconnected in the striato-nigral dopaminergic network, are affected in several childhood diseases including Leigh syndrome (LS). LS is the most common mitochondrial disorder affecting children and usually arise from inhibition of the respiratory chain. This vulnerability is attributed to a particular susceptibility to energetic stress, with mitochondrial inhibition as a common pathogenic pathway. In this study we developed a LS model for neuroprotection trials in mice by using the complex I inhibitor MPTP. We first verified that MPTP significantly inhibits the mitochondrial complex I in the brain (p = 0.018). This model also reproduced the biochemical and pathological features of LS: MPTP increased plasmatic lactate levels (p = 0.023) and triggered basal ganglia degeneration, as evaluated through dopamine transporter (DAT) autoradiography, tyrosine hydroxylase (TH) immunohistochemistry, and dopamine dosage. Striatal DAT levels were markedly decreased after MPTP treatment (p = 0.003). TH immunoreactivity was reduced in the striatum and substantia nigra (p = 0.005), and striatal dopamine was significantly reduced (p < 0.01). Taken together, these results confirm that acute MPTP intoxication in young mice provides a reproducible pharmacological paradigm of LS, thus opening new avenues for neuroprotection research.
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Affiliation(s)
- E Lagrue
- Unité Imagerie et Cerveau, Inserm, U930, Tours, France
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Exploring the neuroprotective effects of modafinil in a marmoset Parkinson model with immunohistochemistry, magnetic resonance imaging and spectroscopy. Brain Res 2008; 1189:219-28. [DOI: 10.1016/j.brainres.2007.10.059] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 10/21/2007] [Accepted: 10/26/2007] [Indexed: 01/19/2023]
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Strome EM, Doudet DJ. Animal Models of Neurodegenerative Disease: Insights from In vivo Imaging Studies. Mol Imaging Biol 2007; 9:186-95. [PMID: 17357857 DOI: 10.1007/s11307-007-0093-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Animal models have been used extensively to understand the etiology and pathophysiology of human neurodegenerative diseases, and are an essential component in the development of therapeutic interventions for these disorders. In recent years, technical advances in imaging modalities such as positron emission tomography (PET) and magnetic resonance imaging (MRI) have allowed the use of these techniques for the evaluation of functional, neurochemical, and anatomical changes in the brains of animals. Combining animal models of neurodegenerative disorders with neuroimaging provides a powerful tool to follow the disease process, to examine compensatory mechanisms, and to investigate the effects of potential treatments preclinically to derive knowledge that will ultimately inform our clinical decisions. This article reviews the literature on the use of PET and MRI in animal models of Parkinson's disease, Huntington's disease, and Alzheimer's disease, and evaluates the strengths and limitations of brain imaging in animal models of neurodegenerative diseases.
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Affiliation(s)
- Elissa M Strome
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, Canada.
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15
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Abstract
Nonhuman primate (NHP) models of Parkinson's disease (PD) play an essential role in the understanding of PD pathophysiology and the assessment of PD therapies. NHP research enabled the identification of environmental risk factors for the development of PD. Electrophysiological studies in NHP models of PD identified the neural circuit responsible for PD motor symptoms, and this knowledge led to the development of subthalamic surgical ablation and deep brain stimulation. Similar to human PD patients, parkinsonian monkeys are responsive to dopamine replacement therapies and present complications associated with their long-term use, a similarity that facilitated the assessment of new symptomatic treatments, such as dopaminergic agonists. New generations of compounds and novel therapies that use directed intracerebral delivery of drugs, cells, and viral vectors benefit from preclinical evaluation in NHP models of PD. There are several NHP models of PD, each with characteristics that make it suitable for the study of different aspects of the disease or potential new therapies. Investigators who use the models and peer scientists who evaluate their use need information about the strengths and limitations of the different PD models and their methods of evaluation. This article provides a critical review of available PD monkey models, their utilization, and how they compare to emerging views of PD as a multietiologic, multisystemic disease. The various models are particularly useful for representing different aspects of PD at selected time points. This conceptualization provides clues for the development of new NHP models and facilitates the clinical translation of findings. As ever, successful application of any model depends on matching the model to the scientific question to be answered. Adequate experimental designs, with multiple outcome measures of clinical relevance and an appropriate number of animals, are essential to minimize the limitations of models and increase their predictive clinical validity.
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Affiliation(s)
- Marina E Emborg
- Preclinical Parkinson's Research Program, Wisconsin National Primate Research Center, University of Wisconsin-Madison, 1223 Capitol Court, Madison, WI 53715, USA.
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16
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Emborg ME, Moirano J, Schafernak KT, Moirano M, Evans M, Konecny T, Roitberg B, Ambarish P, Mangubat E, Ma Y, Eidelberg D, Holden J, Kordower JH, Leestma JE. Basal ganglia lesions after MPTP administration in rhesus monkeys. Neurobiol Dis 2006; 23:281-9. [PMID: 16766201 DOI: 10.1016/j.nbd.2006.03.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2005] [Revised: 03/02/2006] [Accepted: 03/12/2006] [Indexed: 11/17/2022] Open
Abstract
In monkeys, intracarotid infusion of a single low dose of MPTP reliably induces a hemiparkinsonian syndrome that is stable over time. This model has been widely used to assess novel anti-parkinsonian therapies. Here, we report the exceptional finding of severe necrotic lesions that were observed in the basal ganglia (but not in the substantia nigra) of monkeys that received a single intracarotid injection of MPTP followed by gene therapy treatments. Although extensive unilateral dopaminergic nigrostriatal loss was found in all the animals, partial behavioral recovery was observed in the subjects that presented pallidal necrotic lesions. This report discusses possible causes and effects of the necrotic lesions and their locations and the value of the intracarotid MPTP model. Testing novel therapies in monkey models has become an essential step before clinical trials. These results indicate that evaluation of any treatment should consider possible confounding factors that may affect the results.
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Affiliation(s)
- M E Emborg
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, 53715, USA.
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17
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Emborg ME. Evaluation of animal models of Parkinson's disease for neuroprotective strategies. J Neurosci Methods 2004; 139:121-43. [PMID: 15488225 DOI: 10.1016/j.jneumeth.2004.08.004] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2004] [Indexed: 02/07/2023]
Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the progressive loss of dopaminergic nigral neurons and striatal dopamine. Despite the advances of modern therapy to treat the symptoms of PD, most of the patients will eventually experience debilitating disability. The need for neuroprotective strategies that will slow or stop the progression of the disease is clear. The progress in the understanding of the cause and pathogenesis of PD is providing clues for the development of disease-modifying strategies. In that regard, animal models of PD and non-human primate models in particular, are essential for the preclinical evaluation and testing of candidate therapies. However, the diversity of models and different outcome measures used by investigators make it challenging to compare results between neuroprotective agents. In this review we will discuss methods for the selection, development and assessment of animal models of PD, the role of non-human primates and the concept of "multiple models/multiple endpoints" to predict the success in the clinic of neuroprotective strategies.
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Affiliation(s)
- Marina E Emborg
- National Primate Research Center and Department of Anatomy, University of Wisconsin, 1223 Capitol Court, Madison, WI 53715, USA.
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18
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Affiliation(s)
- Louise van der Weerd
- RCS Unit of Biophysics, Intitute of Child Health, University College London, United Kingdom
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19
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Sriram K, Benkovic SA, Hebert MA, Miller DB, O'Callaghan JP. Induction of gp130-related Cytokines and Activation of JAK2/STAT3 Pathway in Astrocytes Precedes Up-regulation of Glial Fibrillary Acidic Protein in the 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine Model of Neurodegeneration. J Biol Chem 2004; 279:19936-47. [PMID: 14996842 DOI: 10.1074/jbc.m309304200] [Citation(s) in RCA: 207] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Reactive gliosis is a hallmark of disease-, trauma-, and chemical-induced damage to the central nervous system. The signaling pathways associated with this response to neural injury remain to be elucidated, but recent evidence implicates the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway. Here, we used the known dopaminergic neurotoxicant, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), to selectively damage striatal dopaminergic nerve terminals and elicit a glial response. We then analyzed changes in gene expression and protein phosphorylation, in vivo, to identify ligands and mediators of the JAK-STAT pathway that accompany glial activation. Administration of MPTP caused rapid tyrosine (Tyr-705) phosphorylation and nuclear translocation of STAT3 in striatal astrocytes, prior to the induction of glial fibrillary acidic protein mRNA and protein. Pharmacological protection of dopaminergic nerve terminals with nomifensine abolished MPTP-mediated phosphorylation and translocation of STAT3 and prevented induction of astrogliosis. Among the Janus kinase family of tyrosine kinases, only JAK2 was associated with the phosphorylation of STAT3 after MPTP and, inhibition of JAK2 by AG490, in vivo, attenuated both the phosphorylation of STAT3 and induction of GFAP. The p44/42 mitogen-activated protein kinase (MAPK; ERK1/2) also was activated by MPTP, but was not associated with activation of STAT3, because serine (Ser-727) was not phosphorylated. The mRNA for ligands of the gp130-JAK/STAT3 signaling pathway, interleukin-6, leukemia inhibitory factor, and oncostatin M were elevated prior to activation of STAT3 and induction of astrogliosis; neuroprotection with nomifensine blocked these effects of MPTP. Taken together, our results suggest that the gp130-mediated activation of JAK2/STAT3 signaling pathway may play a key role in the induction of astrogliosis.
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MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/pharmacology
- Active Transport, Cell Nucleus
- Animals
- Antigens, CD/biosynthesis
- Astrocytes/metabolism
- Astrocytes/physiology
- Chromatography, High Pressure Liquid
- Cytokine Receptor gp130
- DNA, Complementary/metabolism
- DNA-Binding Proteins/metabolism
- Dimerization
- Dopamine/metabolism
- Dopamine Agents/pharmacology
- Dopamine Uptake Inhibitors/pharmacology
- Enzyme Activation
- Enzyme-Linked Immunosorbent Assay
- Gene Expression Regulation
- Glial Fibrillary Acidic Protein/metabolism
- Immunoblotting
- Immunohistochemistry
- Interleukin-6/metabolism
- Janus Kinase 2
- Leukemia Inhibitory Factor
- Ligands
- MAP Kinase Signaling System
- Male
- Membrane Glycoproteins/biosynthesis
- Mice
- Mice, Inbred C57BL
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases/metabolism
- Models, Biological
- Nomifensine/pharmacology
- Oncostatin M
- Peptides/metabolism
- Phosphorylation
- Protein Transport
- Protein-Tyrosine Kinases/metabolism
- Proto-Oncogene Proteins
- RNA/metabolism
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- STAT3 Transcription Factor
- Signal Transduction
- Time Factors
- Tissue Distribution
- Trans-Activators/metabolism
- Tyrosine/metabolism
- Up-Regulation
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Affiliation(s)
- Krishnan Sriram
- HELD/TMBB, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV 26505, USA
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20
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Podell M, Hadjiconstantinou M, Smith MA, Neff NH. Proton magnetic resonance imaging and spectroscopy identify metabolic changes in the striatum in the MPTP feline model of parkinsonism. Exp Neurol 2003; 179:159-66. [PMID: 12618122 DOI: 10.1016/s0014-4886(02)00015-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to adult, male cats to model Parkinson's disease (PD), and utilized proton magnetic resonance imaging (MRI) and spectroscopy (MRS) at a field strength of 1.5 T to identify metabolic degenerative changes in the striatum in vivo. Neurologic status and somatosensory-evoked potentials in vivo, as well as postmortem striatal histopathological and immunohistochemical parameters, were examined. Nine cats were equally divided into three groups and treated daily for 10 days as follows: saline, MPTP, and pargyline (a monoamine oxidase inhibitor) plus MPTP. The MPTP-treated cats displayed bradykinesia, head tremor, and reduced oculovestibular reflex activity. MRI showed a diffuse increase of the T2-weighted signal in the striatum of two MPTP-treated cats. Analysis of the MRS spectra indicated significantly lower N-acetylaspartate/creatine (CR) and glutamine-glutamate complex/CR ratios than the control baseline. Two MPTP-treated cats had low choline-containing compounds/CR ratio, whereas a lactate peak was present in all MPTP-treated cats. In the striatum of the MPTP-treated cats, there was a significant decline of tyrosine hydroxylase immunoreactivity and histological evidence for a diffuse cytotoxic reaction. Pretreatment with pargyline attenuated the MPTP-induced clinical signs, MRI and MRS changes, and the histopathological and immunoreactivity alterations. We conclude that proton MRI/MRS is a sensitive, noninvasive measure of neural toxicity and biochemical alteration of the striatum in a feline model of PD.
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Affiliation(s)
- Michael Podell
- Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH 43210, USA
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21
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Abstract
The main aim of this review is to describe some of the many animal models that have proved to be valuable from a neuroimaging perspective. This paper complements other articles in this volume, with a focus on animal models of the pathology of human brain disorders for investigations with modern non-invasive neuroimaging techniques. The use of animal model systems forms a fundamental part of neuroscience research efforts to improve the prevention, diagnosis, understanding and treatment of neurological conditions. Without such models it would be impossible to investigate such topics as the underlying mechanisms of neuronal cell damage and death, or to screen compounds for possible anticonvulsant properties. The adequacy of any one particular model depends on the suitability of information gained during experimental conditions. It is important, therefore, to understand the various types of animal model available and choose an appropriate model for the research question.
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Affiliation(s)
- Mark F Lythgoe
- RCS Unit of Biophysics, Institute of Child Health, University College London, UK
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22
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Chassain C, Eschalier A, Durif F. Assessment of motor behavior using a video system and a clinical rating scale in parkinsonian monkeys lesioned by MPTP. J Neurosci Methods 2001; 111:9-16. [PMID: 11574115 DOI: 10.1016/s0165-0270(01)00425-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The best current model of Parkinson's disease is the primate treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Quantification of animal movement is important for the study of severity of parkinsonian syndrome induced by MPTP and response to drug treatments. Both require clinical rating scales that measure motor behavior with well-defined objective items. However, evaluations using these scales depend on the observer scoring the different items, according to his/her experience. The video image analyzer system, which produces an activity curve in correlation with the visual study of animal motor behavior, offers an automatic evaluation method that is observer-independent and reproducible. Using such an system we defined items correlated with those used in clinical rating scales that are sensitive to animal motor changes, decrease in movements with MPTP intoxication and alleviation afforded by levodopa: global locomotor activity and specific activities (climbing, social interactions, eating and drinking behaviors).
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Affiliation(s)
- C Chassain
- Unité INSERM EMI 9904, Faculté de Médecine et Pharmacie, place Henri-Dunand, 63003, Clermont-Ferrand, France.
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23
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Guzman R, Meyer M, Lövblad KO, Ozdoba C, Schroth G, Seiler RW, Widmer HR. Striatal grafts in a rat model of Huntington's disease: time course comparison of MRI and histology. Exp Neurol 1999; 156:180-90. [PMID: 10192789 DOI: 10.1006/exnr.1999.7015] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Survival and integration into the host brain of grafted tissue are crucial factors in neurotransplantation approaches. The present study explored the feasibility of using a clinical MR scanner to study striatal graft development in a rat model of Huntington's disease. Rat fetal lateral ganglionic eminences grown as free-floating roller-tube cultures were grafted into the quinolinic acid-lesioned striatum, and T1- and T2-weighted sequences were acquired at 2, 7, 21, and 99 days posttransplantation. MR images were then compared with images of corresponding histological sections. The lesion-induced striatal degeneration caused a progressive ventricle enlargement, which was significantly different from controls at 21 days posttransplantation. Seven days posttransplantation, T1-weighted images revealed a defined liquid-isointense signal surrounded by a hyperintense rim at the site of graft placement, which was found unaltered for the first 21 days posttransplantation, whereas a hypointense graft signal was detected at 99 days posttransplantation. At 2 days posttransplantation, T2-weighted images showed the graft region as a hyperintense area surrounded by a rim of low signal intensity but at later time-points graft location could not be further verified. Measures for graft size and ventricle size obtained from MR images highly correlated with measures obtained from histologically processed sections (R = 0.8, P < 0.001). In conclusion, the present study shows that fetal rat lateral ganglionic eminences grown as free-floating roller-tube cultures can be successfully grafted in a rat Huntington model and that a clinical MR scanner offers a useful noninvasive tool for studying striatal graft development.
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Affiliation(s)
- R Guzman
- Department of Neurosurgery, Inselspital, Bern, Switzerland
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24
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Bakshi R, Miletich RS, Kinkel PR, Emmet ML, Kinkel WR. High-resolution fluorodeoxyglucose positron emission tomography shows both global and regional cerebral hypometabolism in multiple sclerosis. J Neuroimaging 1998; 8:228-34. [PMID: 9780855 DOI: 10.1111/jon199884228] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The authors study brain regional glucose metabolism prospectively in multiple sclerosis (MS) using high-resolution 2-[18-F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) in 25 MS patients of the Dent Neurologic Institute compared with 6 healthy subjects. Glucose metabolism is measured in 20 regions of interest using a line-profile technique. Compared with control subjects, a 9% reduction in total brain glucose metabolism is noted in MS patients (p < 0.05). Hypometabolism is widespread, including the cerebral cortex, subcortical nuclei, supratentorial white matter, and infratentorial structures. This reduction represents absolute regional decreases ranging from 3% to 18%. The most dramatic absolute reductions occur in the superior mesial frontal cortex, superior dorsolateral frontal cortex, mesial occipital cortex, lateral occipital cortex, deep inferior parietal white matter, and pons. The regional hypometabolism in the superior mesial frontal cortex and superior dorsolateral frontal cortex is statistically significant (p < 0.05), whereas the changes in the mesial occipital cortex (p = 0.07) and the lateral occipital cortex (p = 0.09) approach significance. The authors' findings suggest that widespread cerebral dysfunction occurs in MS, and that diaschisis or neuronal system disconnection resulting from white matter disease plays a major role. Cortical gray matter hypometabolism may also reflect direct MS involvement. The quantitative cerebral abnormalities detected by FDG PET may serve as a marker of disease activity in understanding the pathophysiological expression and therapeutic response of MS.
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Affiliation(s)
- R Bakshi
- Dent Neurologic Institute, Millard Fillmore Health System, State University of New York, School of Medicine and Biomedical Sciences, Buffalo, NY, USA
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25
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Willis GL, Armstrong SM. Orphan neurones and amine excess: the functional neuropathology of Parkinsonism and neuropsychiatric disease. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1998; 27:177-242. [PMID: 9729369 DOI: 10.1016/s0165-0173(98)00013-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The aetiology and treatment of Parkinsonism is currently conceptualised within a dopamine (DA) deficiency-repletion framework. Loss of striatal DA is thought to cause motor impairment of which tremor, bradykinaesia and rigidity are prominent features. Repletion of deficient DA should at least minimise parkinsonian signs and symptoms. In Section 2, based on extensive pre-clinical and clinical findings, the instability of this approach to Parkinsonism is scrutinised as the existing negative findings challenging the DA deficiency hypothesis are reviewed and reinterpreted. In Section 3 it is suggested that Parkinsonism is due to a DA excess far from the striatum in the area of the posterior lateral hypothalamus (PLH) and the substantia nigra (SN). This unique area, around the diencephalon/mesencephalon border (DCMCB), is packed with many ascending and descending fibres which undergo functional transformation during degeneration, collectively labelled 'orphan neurones'. These malformed cells remain functional resulting in pathological release of transmitter and perpetual neurotoxicity. Orphan neurone formation is commonly observed in the PLH of animals and in man exhibiting Parkinsonism. The mechanism by which orphan neurones impair motor function is analogous to that seen in the diseased human heart. From this perspective, to conceptualise orphan neurones at the DCMCB as 'Time bombs in the brain' is neither fanciful nor unrealistic [E.M. Stricker, M.J. Zigmond, Comments on effects of nigro-striatal dopamine lesions, Appetite 5 (1984) 266-267] as the DA excess phenomenon demands a different therapeutic approach for the management of Parkinsonism. In Section 4 the focus is on this novel concept of treatment strategies by concentrating on non-invasive, pharmacological and surgical modification of functional orphan neurones as they affect adjacent systems. The Orphan neurone/DA excess hypothesis permits a more comprehensive and defendable interpretation of the interrelationship between Parkinsonism and schizophrenia and other related disorders.
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Affiliation(s)
- G L Willis
- The Bronowski Institute of Behavioural Neuroscience, Coliban Medical Centre, Kyneton, Victoria 3444, Australia
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Abstract
Amyotrophic lateral sclerosis (ALS) is probably biphasic. An initial trigger(s) is followed by a terminal cascade coinciding with the onset of neurological deficits. The terminal cascade involves interactive multifactorial pathogenic mechanisms. Aging must play a crucial role leading to multiple defective or degraded gene products accumulating with progressing years. This in turn leads to failure of receptor integrity and resulting excitotoxicity, free radical accumulation, failure of neurotrophism, and possibly immunological disturbances. These events are predated by months or years by a trigger which is also likely to be multifactorial and cumulative. Evidence suggests that environmental factors may be important triggers. Failure of specific glutamate transporters and calcium binding proteins may account for selective vulnerability of the corticomotoneuronal system. It is postulated that in ALS the primary target cell is the corticomotoneuron or the local circuit interneurons which modulate its activity. Glia cells may play an important role in the demise of the corticomotoneuronal cell. The disordered corticomotoneuron induces excessive excitatory transmitter (glutamate?) release at the corticomotoneuronal-spinal-motoneuronal synapse resulting in the subsequent demise of this neuron.
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Affiliation(s)
- A Eisen
- Neuromuscular Diseases Unit, Vancouver General Hospital, British Columbia, Canada
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