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Unnithan D, Sartaj A, Iqubal MK, Ali J, Baboota S. A neoteric annotation on the advances in combination therapy for Parkinson's disease: nanocarrier-based combination approach and future anticipation. Part I: exploring theoretical insights and pharmacological advances. Expert Opin Drug Deliv 2024; 21:423-435. [PMID: 38481172 DOI: 10.1080/17425247.2024.2331214] [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: 06/03/2023] [Accepted: 03/12/2024] [Indexed: 03/22/2024]
Abstract
INTRODUCTION Parkinson's disease (PD) is a neurological condition defined by a substantial reduction in dopamine-containing cells in the substantia nigra. Levodopa (L-Dopa) is considered the gold standard in treatment. Recent research has clearly shown that resistance to existing therapies can develop. Moreover, the involvement of multiple pathways in the nigrostriatal dopaminergic neuronal loss suggests that modifying the treatment strategy could effectively reduce this degeneration. AREAS COVERED This review summarizes the key concerns with treating PD patients and the combinations, aimed at effectively managing PD. Part I focuses on the clinical diagnosis at every stage of the disease as well as the pharmacological treatment strategies that are applied throughout its course. It methodically elucidates the potency of multifactorial interventions in attenuating the disease trajectory, substantiating the rationale for co-administration of dual or multiple therapeutic agents. Significant emphasis is laid on evidence-based pharmacological combinations for PD management. EXPERT OPINION By utilizing multiple drugs in a combination fashion, this approach can leverage the additive or synergistic effects of these agents, amplify the spectrum of treatment, and curtail the risk of side effects by reducing the dose of each drug, demonstrating significantly greater efficacy.
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Affiliation(s)
- Devika Unnithan
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi, India
| | - Ali Sartaj
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi, India
| | - Mohammad Kashif Iqubal
- Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Texas A&M University, College Station, TX, USA
| | - Javed Ali
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi, India
| | - Sanjula Baboota
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi, India
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Omotosho AO, Tajudeen YA, Oladipo HJ, Yusuff SI, AbdulKadir M, Muili AO, Egbewande OM, Yusuf RO, Faniran ZO, Afolabi AO, El‐Sherbini MS. Parkinson's disease: Are gut microbes involved? Brain Behav 2023; 13:e3130. [PMID: 37340511 PMCID: PMC10454343 DOI: 10.1002/brb3.3130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 06/05/2023] [Accepted: 06/05/2023] [Indexed: 06/22/2023] Open
Abstract
INTRODUCTION Parkinson's disease (PD) is a neurodegenerative disorder that affects more than 10 million individuals worldwide. It is characterized by motor and sensory deficits. Research studies have increasingly demonstrated a correlation between Parkinson's disease and alternations in the composition of the gut microbiota in affected patients. Also, the significant role of prebiotics and probiotics in gastrointestinal and neurological conditions is imperative to understand their relation to Parkinson's disease. METHOD To explore the scientific interaction of the gut-microbiota-brain axis and its association with Parkinson's disease, a comprehensive narrative review of the relevant literature was conducted. Articles were retrieved systematically from reputable sources, including PubMed, Science Direct, World Health Organization (WHO), and Advanced Google Scholar. Key search terms included are "Parkinson's Disease", "Gut Microbiome", "Braak's Theory", "Neurological Disorders", and "Gut-brain axis". Articles included in our review are published in English and they provide detailed information on the relationship between Parkinson's disease and gut microbiota RESULTS: This review highlights the impact of gut microbiota composition and associated factors on the progression of Parkinson's disease. Evidence-based studies highlighting the existing evidence of the relationship between Parkinson's disease and alteration in gut microbiota are discussed. Consequently, the potential mechanisms by which the gut microbiota may affect the composition of the gut microbiota were revealed, with a particular emphasis on the role of the gut-brain axis in this interplay. CONCLUSION Understanding the complex interplay between gut microbiota and Parkinson's disease is a potential implication for the development of novel therapeutics against Parkinson's disease. Following the existing relationship demonstrated by different evidence-based studies on Parkinson's disease and gut microbiota, our review concludes by providing recommendations and suggestions for future research studies with a particular emphasis on the impact of the microbiota-brain axis on Parkinson's disease.
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Affiliation(s)
- Abass Olawale Omotosho
- Department of Microbiology, Faculty of Pure and Applied SciencesKwara State University, Malete‐IlorinIlorinNigeria
| | - Yusuf Amuda Tajudeen
- Department of Microbiology, Faculty of Life SciencesUniversity of IlorinIlorinNigeria
- Faculty of Pharmaceutical SciencesUniversity of IlorinIlorinNigeria
| | - Habeebullah Jayeola Oladipo
- Department of Microbiology, Faculty of Life SciencesUniversity of IlorinIlorinNigeria
- Department of Epidemiology and Medical Statistics, Faculty of Public Health, College of MedicineUniversity of IbadanIbadanNigeria
| | - Sodiq Inaolaji Yusuff
- Department of Medicine, Faculty of Clinical SciencesObafemi Awolowo UniversityIfeNigeria
| | - Muritala AbdulKadir
- Department of Epidemiology and Medical Statistics, Faculty of Public Health, College of MedicineUniversity of IbadanIbadanNigeria
| | | | - Oluwaseyi Muyiwa Egbewande
- Department of Epidemiology and Medical Statistics, Faculty of Public Health, College of MedicineUniversity of IbadanIbadanNigeria
| | - Rashidat Onyinoyi Yusuf
- Department of Epidemiology and Medical Statistics, Faculty of Public Health, College of MedicineUniversity of IbadanIbadanNigeria
| | | | - Abdullateef Opeyemi Afolabi
- Faculty of Biomedical Sciences, Department of Microbiology and ImmunologyKampala International UniversityBushenyiUganda
| | - Mona Said El‐Sherbini
- Narrative Medicine and Planetary Health, Integrated Program of Kasr Al-Ainy (IPKA), Faculty of MedicineCairo UniversityCairoEgypt
- Invited Facultythe Nova Institute for HealthBaltimoreMDUSA
- Department of Medical Parasitology, Faculty of MedicineCairo UniversityCairoEgypt
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GÜNEŞ M, KARAVANA SY. Non-Oral Drug Delivery in Parkinson’s Disease: Current Applications and Future. Turk J Pharm Sci 2022; 19:343-352. [DOI: 10.4274/tjps.galenos.2021.95226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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4
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Brooks DJ. Imaging Familial and Sporadic Neurodegenerative Disorders Associated with Parkinsonism. Neurotherapeutics 2021; 18:753-771. [PMID: 33432494 PMCID: PMC8423977 DOI: 10.1007/s13311-020-00994-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2020] [Indexed: 11/24/2022] Open
Abstract
In this paper, the structural and functional imaging changes associated with sporadic and genetic Parkinson's disease and atypical Parkinsonian variants are reviewed. The role of imaging for supporting diagnosis and detecting subclinical disease is discussed, and the potential use and drawbacks of using imaging biomarkers for monitoring disease progression is debated. Imaging changes associated with nonmotor complications of PD are presented. The similarities and differences in imaging findings in Lewy body dementia, Parkinson's disease dementia, and Alzheimer's disease are discussed.
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Affiliation(s)
- David J Brooks
- Department of Nuclear Medicine, Aarhus University, Aarhus N, 8200, Denmark.
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE4 5PL, UK.
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Kabra A, Baghel US, Hano C, Martins N, Khalid M, Sharma R. Neuroprotective potential of Myrica esulenta in Haloperidol induced Parkinson's disease. J Ayurveda Integr Med 2020; 11:448-454. [PMID: 32912644 PMCID: PMC7772500 DOI: 10.1016/j.jaim.2020.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 05/22/2020] [Accepted: 06/12/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Myrica esculenta is a notable therapeutic plant widely utilized in Indian system of medicine. Ayurvedic literature reported fruit and bark of this plant is used in gulma, jvara, arsa, grahani, pandu roga, hrillasa, mukha roga, kasa, svasa, agnimandhya, aruchi, meha, and kantharoga. OBJECTIVE The present study aimed to investigate the neuroprotective potential of "Himalayan Bayberry" (Myrica esculenta Buch.-Ham. ex D. Don) leaves methanol extract in Parkinson's disease induced by haloperidol. MATERIALS AND METHODS The present investigation was completed in wistar rats, in which Parkinson's disease (PD) was induced with haloperidol 1 mg/kg, intraperitoneally. The rats were randomly divided into six gatherings and the test animals received the methanolic extract of M. esculenta (MEME) at a dose of 50, 100 and 200 mg/kg, orally for one week. Various behavioural, biochemical and histopathological parameters were estimated in haloperidol exposed rats. RESULTS MEME demonstrated significant and dose-dependent increment in behavioural activity and improved muscle coordination. The significant diminution in malonaldehyde level while improved the level of antioxidant enzymes like catalase, superoxide dismutase and reduced glutathione in extract treated group were observed as compared to the control group. Histopathological changes revealed MEME significantly reduced haloperidol-induced damage in the substantia nigra and there was very little neuronal atrophy. CONCLUSION The outcomes showed the defensive role of M. esculenta against PD. The mechanism of protection may be due to an escalation of cellular antioxidants.
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Affiliation(s)
- Atul Kabra
- IKG Punjab Technical University, Kapurthala, Punjab, India; School of Pharmacy, Raffles University, Neemrana, 301705, Alwar, Rajasthan, India.
| | - Uttam Singh Baghel
- Department of Pharmacy, University of Kota, Kota, 325003, Rajasthan, India
| | - Christophe Hano
- Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRA USC1328, Orleans University, 45067 CEDEX 2, Orléans, France; Bioactifs et Cosmetiques, CNRS GDR 3711 Orleans, 45067 CEDEX 2, Orléans, France
| | - Natalia Martins
- Faculty of Medicine, University of Porto, Alameda Prof. Hernani Monteiro, 4200-319, Porto, Portugal; Institute for Research and Innovation in Heath (i3S), University of Porto, Rua Alfredo Allen, 4200-135, Porto, Portugal
| | - Mohammad Khalid
- Department of Pharmacognosy, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj, 11942, Saudi Arabia
| | - Rohit Sharma
- Department of Rasa Shastra and Bhaishajya Kalpana, Faculty of Ayurveda, Institute of Medical Sciences, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India
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The Rehapiano-Detecting, Measuring, and Analyzing Action Tremor Using Strain Gauges. SENSORS 2020; 20:s20030663. [PMID: 31991705 PMCID: PMC7038321 DOI: 10.3390/s20030663] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/23/2020] [Accepted: 01/23/2020] [Indexed: 02/02/2023]
Abstract
We have developed a device, the Rehapiano, for the fast and quantitative assessment of action tremor. It uses strain gauges to measure force exerted by individual fingers. This article verifies the device's capability to measure and monitor the development of upper limb tremor. The Rehapiano uses a precision, 24-bit, analog-to-digital converter and an Arduino microcomputer to transfer raw data via a USB interface to a computer for processing, database storage, and evaluation. First, our experiments validated the device by measuring simulated tremors with known frequencies. Second, we created a measurement protocol, which we used to measure and compare healthy patients and patients with Parkinson's disease. Finally, we evaluated the repeatability of a quantitative assessment. We verified our hypothesis that the Rehapiano is able to detect force changes, and our experimental results confirmed that our system is capable of measuring action tremor. The Rehapiano is also sensitive enough to enable the quantification of Parkinsonian tremors.
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7
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Olanow CW. Levodopa is the best symptomatic therapy for PD: Nothing more, nothing less. Mov Disord 2019; 34:812-815. [DOI: 10.1002/mds.27690] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/19/2019] [Accepted: 03/20/2019] [Indexed: 12/22/2022] Open
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Lin MM, Laureno R. Less Pulsatile Levodopa Therapy (6 Doses Daily) Is Associated with a Reduced Incidence of Dyskinesia. J Mov Disord 2019; 12:37-42. [PMID: 30732431 PMCID: PMC6369375 DOI: 10.14802/jmd.18046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/12/2018] [Indexed: 11/30/2022] Open
Abstract
Objective To evaluate whether less pulsatile levodopa therapy (LPT) can reduce the development of levodopa-induced dyskinesia (LID). Methods This is a retrospective cohort study of patients with Parkinson’s disease at the movement disorders clinic of Medstar Washington Hospital Center. The study was not blinded or randomized. Patients were seen between August 2002 and August 2018. During these years, we treated patients with less pulsatile (6 doses daily) levodopa treatment to reduce LID. Occurrence of LID was recorded. Results Ninety-five patients with Parkinson’s disease taking levodopa were divided into two groups: 1) patients who were initially managed on LPT or who switched from traditional therapy (TT) (n = 61) (mean disease duration: 7.7 ± 4.8 years, mean levodopa duration: 5.6 ± 4.5 years and mean observation time: 4.3 ± 3.4 years), and 2) patients on TT throughout the observation period or until they developed dyskinesia (n = 34) (mean disease duration: 8.3 ± 3.8 years, mean levodopa duration: 6.2 ± 4.2 years and mean observation time: 4.1 ± 3.4 years). Three of the 61 LPT patients developed dyskinesia during the observation period. One of the patients developed dyskinesia after being switched to pulsatile doses by another doctor. In the other two, dyskinesia was minimal. In contrast to this 4.9% cumulative incidence, dyskinesia occurred in 50% (17/34) of TT patients, an incidence similar to that in published data (p < 0.001). Conclusion Less pulsatile levodopa with 6 daily doses was associated with a low incidence of LID. Further study of this method of treatment is warranted.
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Affiliation(s)
- Mark M Lin
- Department of Neurology, Medstar Washington Hospital Center, Medstar Georgetown University Hospital and Georgetown University School of Medicine, Washington, DC, USA
| | - Robert Laureno
- Department of Neurology, Medstar Washington Hospital Center, Medstar Georgetown University Hospital and Georgetown University School of Medicine, Washington, DC, USA
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You H, Mariani LL, Mangone G, Le Febvre de Nailly D, Charbonnier-Beaupel F, Corvol JC. Molecular basis of dopamine replacement therapy and its side effects in Parkinson's disease. Cell Tissue Res 2018. [PMID: 29516217 DOI: 10.1007/s00441-018-2813-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
There is currently no cure for Parkinson's disease. The symptomatic therapeutic strategy essentially relies on dopamine replacement whose efficacy was demonstrated more than 50 years ago following the introduction of the dopamine precursor, levodopa. The spectacular antiparkinsonian effect of levodopa is, however, balanced by major limitations including the occurrence of motor complications related to its particular pharmacokinetic and pharmacodynamic properties. Other therapeutic strategies have thus been developed to overcome these problems such as the use of dopamine receptor agonists, dopamine metabolism inhibitors and non-dopaminergic drugs. Here we review the pharmacology and molecular mechanisms of dopamine replacement therapy in Parkinson's disease, both at the presynaptic and postsynaptic levels. The perspectives in terms of novel drug development and prediction of drug response for a more personalised medicine will be discussed.
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Affiliation(s)
- Hana You
- Sorbonne Université, UPMC Univ Paris 06, UMR S 1127, ICM, Hôpital Pitié-Salpêtrière, Paris, France.,INSERM, Unit 1127, CIC 1422, NS-PARK/FCRIN, Hôpital Pitié-Salpêtrière, Paris, France.,CNRS, Unit 7225, Hôpital Pitié-Salpêtrière, Paris, France.,Assistance Publique Hôpitaux de Paris, Department of Neurology, Hôpital Pitié-Salpêtrière, Paris, France.,Department of Neurology, University Hospital (Inselspital) and University of Bern, Freiburgstrasse 18, 3010, Bern, Switzerland
| | - Louise-Laure Mariani
- Sorbonne Université, UPMC Univ Paris 06, UMR S 1127, ICM, Hôpital Pitié-Salpêtrière, Paris, France.,INSERM, Unit 1127, CIC 1422, NS-PARK/FCRIN, Hôpital Pitié-Salpêtrière, Paris, France.,CNRS, Unit 7225, Hôpital Pitié-Salpêtrière, Paris, France.,Assistance Publique Hôpitaux de Paris, Department of Neurology, Hôpital Pitié-Salpêtrière, Paris, France
| | - Graziella Mangone
- Sorbonne Université, UPMC Univ Paris 06, UMR S 1127, ICM, Hôpital Pitié-Salpêtrière, Paris, France.,INSERM, Unit 1127, CIC 1422, NS-PARK/FCRIN, Hôpital Pitié-Salpêtrière, Paris, France.,CNRS, Unit 7225, Hôpital Pitié-Salpêtrière, Paris, France.,Assistance Publique Hôpitaux de Paris, Department of Neurology, Hôpital Pitié-Salpêtrière, Paris, France
| | - Delphine Le Febvre de Nailly
- INSERM, Unit 1127, CIC 1422, NS-PARK/FCRIN, Hôpital Pitié-Salpêtrière, Paris, France.,Assistance Publique Hôpitaux de Paris, Department of Pharmacy, Hôpital Pitié-Salpêtrière, Paris, France
| | - Fanny Charbonnier-Beaupel
- Assistance Publique Hôpitaux de Paris, Department of Pharmacy, Hôpital Pitié-Salpêtrière, Paris, France
| | - Jean-Christophe Corvol
- Sorbonne Université, UPMC Univ Paris 06, UMR S 1127, ICM, Hôpital Pitié-Salpêtrière, Paris, France. .,INSERM, Unit 1127, CIC 1422, NS-PARK/FCRIN, Hôpital Pitié-Salpêtrière, Paris, France. .,CNRS, Unit 7225, Hôpital Pitié-Salpêtrière, Paris, France. .,Assistance Publique Hôpitaux de Paris, Department of Neurology, Hôpital Pitié-Salpêtrière, Paris, France. .,CIC Neurosciences, ICM building, Hôpital Pitié-Salpêtrière, 47/83 Boulevard de l'Hôpital, 75013, Paris, France.
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Olanow C, Kieburtz K, Katz R. Clinical approaches to the development of a neuroprotective therapy for PD. Exp Neurol 2017. [DOI: 10.1016/j.expneurol.2017.06.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Honma M, Murai Y, Shima S, Yotsumoto Y, Kuroda T, Futamura A, Shiromaru A, Murakami I, Kawamura M. Spatial distortion related to time compression during spatiotemporal production in Parkinson's disease. Neuropsychologia 2017; 102:61-69. [DOI: 10.1016/j.neuropsychologia.2017.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 06/03/2017] [Accepted: 06/06/2017] [Indexed: 12/16/2022]
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12
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Mallik AK, Drzezga A, Minoshima S. Molecular Imaging and Precision Medicine in Dementia and Movement Disorders. PET Clin 2017; 12:119-136. [DOI: 10.1016/j.cpet.2016.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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13
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Brooks DJ. Molecular imaging of dopamine transporters. Ageing Res Rev 2016; 30:114-21. [PMID: 26802555 DOI: 10.1016/j.arr.2015.12.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/26/2015] [Accepted: 12/29/2015] [Indexed: 12/31/2022]
Abstract
The dopamine transporter (DAT) is responsible for clearance of dopamine from the synaptic cleft after its release. Imaging DAT availability provides a measure of dopamine terminal function and a method for detecting the striatal dopamine terminal dysfunction present in idiopathic Parkinson's disease (PD) and atypical neurodegenerative parkinsonian disorders such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD). DAT imaging with positron emission tomography (PET) or single photon emission computed tomography (SPECT) can be used to support or refute a diagnosis of dopamine deficient parkinsonism in cases where this is unclear and rationalise a trial of dopamine replacement agents as therapy. It can also detect subclinical dopaminergic dysfunction when present in subjects at risk for PD such as relatives of patients, susceptibility gene mutation carriers, and subjects with late onset hyposmia or sleep disorders. The presence of normal DAT availability on imaging can help categorise "subjects without evidence of dopamine deficiency" (SWEDDs) who on occasion mimic PD and include dystonic tremors, drug-induced and psychogenic parkinsonism in their ranks. Reduced levels of baseline striatal DAT availability on PET or SPECT scanning, however, should be regarded as supportive rather than diagnostic of dopamine deficient parkinsonism.
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Brooks DJ. Imaging of genetic and degenerative disorders primarily causing Parkinsonism. HANDBOOK OF CLINICAL NEUROLOGY 2016; 135:493-505. [PMID: 27432680 DOI: 10.1016/b978-0-444-53485-9.00024-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In this chapter the structural and functional imaging changes associated with both genetic causes of Parkinson's disease and the sporadic condition are reviewed. The role of imaging for supporting diagnosis and detecting subclinical disease is discussed and the potential use and drawbacks of using imaging biomarkers for monitoring disease progression are debated. Additionally, the use of imaging for differentiating atypical parkinsonian syndromes from Parkinson's disease is presented.
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Affiliation(s)
- David J Brooks
- Department of Medicine, Imperial College London, London, UK.
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Schneider JS, Cambi F, Gollomp SM, Kuwabara H, Brašić JR, Leiby B, Sendek S, Wong DF. GM1 ganglioside in Parkinson's disease: Pilot study of effects on dopamine transporter binding. J Neurol Sci 2015; 356:118-23. [PMID: 26099170 PMCID: PMC4545312 DOI: 10.1016/j.jns.2015.06.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Revised: 05/26/2015] [Accepted: 06/14/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE GM1 ganglioside has been suggested as a treatment for Parkinson's disease (PD), potentially having symptomatic and disease modifying effects. The current pilot imaging study was performed to examine effects of GM1 on dopamine transporter binding, as a surrogate measure of disease progression, studied longitudinally. METHODS Positron emission tomography (PET) imaging data were obtained from a subset of subjects enrolled in a delayed start clinical trial of GM1 in PD [1]: 15 Early-start (ES) subjects, 14 Delayed-start (DS) subjects, and 11 Comparison (standard-of-care) subjects. Treatment subjects were studied over a 2.5 year period while Comparison subjects were studied over 2 years. Dynamic PET scans were performed over 90 min following injection of [(11)C]methylphenidate. Regional values of binding potential (BPND) were analyzed for several striatal volumes of interest. RESULTS Clinical results for this subset of subjects were similar to those previously reported for the larger study group. ES subjects showed early symptomatic improvement and slow symptom progression over the study period. DS and Comparison subjects were initially on the same symptom progression trajectory but diverged once DS subjects received GM1 treatment. Imaging results showed significant slowing of BPND loss in several striatal regions in GM1-treated subjects and in some cases, an increased BPND in some striatal regions was detected after GM1 use. INTERPRETATION Results of this pilot imaging study provide additional data to suggest a potential disease modifying effect of GM1 on PD. These results need to be confirmed in a larger number of subjects.
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Affiliation(s)
- Jay S Schneider
- Department of Pathology, Anatomy and Cell Biology and Parkinson's Disease Research Unit, Thomas Jefferson University, Philadelphia, PA 19107, United States.
| | - Franca Cambi
- Dept. of Neurology, University of Pittsburgh School of Medicine and Pittsburgh VAMC, Pittsburgh, PA 15213, United States
| | - Stephen M Gollomp
- Division of Neurology, Lankenau Medical Center, Wynnewood, PA 19096, United States
| | - Hiroto Kuwabara
- Division of Nuclear Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, MD 21287, United States
| | - James R Brašić
- Division of Nuclear Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, MD 21287, United States
| | - Benjamin Leiby
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Stephanie Sendek
- Department of Pathology, Anatomy and Cell Biology and Parkinson's Disease Research Unit, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Dean F Wong
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States; Department of Psychiatry and Behavior Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States; Solomon Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States
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Martino G, Capasso M, Nasuti M, Bonanni L, Onofrj M, Thomas A. Dopamine transporter single-photon emission computerized tomography supports diagnosis of akinetic crisis of parkinsonism and of neuroleptic malignant syndrome. Medicine (Baltimore) 2015; 94:e649. [PMID: 25837755 PMCID: PMC4554017 DOI: 10.1097/md.0000000000000649] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Akinetic crisis (AC) is akin to neuroleptic malignant syndrome (NMS) and is the most severe and possibly lethal complication of parkinsonism. Diagnosis is today based only on clinical assessments yet is often marred by concomitant precipitating factors. Our purpose is to evidence that AC and NMS can be reliably evidenced by FP/CIT single-photon emission computerized tomography (SPECT) performed during the crisis. Prospective cohort evaluation in 6 patients. In 5 patients, affected by Parkinson disease or Lewy body dementia, the crisis was categorized as AC. One was diagnosed as having NMS because of exposure to risperidone. In all FP/CIT, SPECT was performed in the acute phase. SPECT was repeated 3 to 6 months after the acute event in 5 patients. Visual assessments and semiquantitative evaluations of binding potentials (BPs) were used. To exclude the interference of emergency treatments, FP/CIT BP was also evaluated in 4 patients currently treated with apomorphine. During AC or NMS, BP values in caudate and putamen were reduced by 95% to 80%, to noise level with a nearly complete loss of striatum dopamine transporter-binding, corresponding to the "burst striatum" pattern. The follow-up re-evaluation in surviving patients showed a recovery of values to the range expected for Parkinsonisms of same disease duration. No binding effects of apomorphine were observed. By showing the outstanding binding reduction, presynaptic dopamine transporter ligand can provide instrumental evidence of AC in Parkinsonism and NMS.
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Affiliation(s)
- G Martino
- From the Department of Radiology and Radiotherapy, Nuclear Medicine University G. d'Annunzio of Chieti-Pescara (GM, MN); Neurology Clinic, State Hospital (MC, LB, MO, AT); and Department of Neuroscience and Imaging and Aging Research Center, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy (LB, MO, AT)
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The Neuroprotective Mechanism of Low-Frequency rTMS on Nigral Dopaminergic Neurons of Parkinson's Disease Model Mice. PARKINSONS DISEASE 2015; 2015:564095. [PMID: 25883828 PMCID: PMC4390107 DOI: 10.1155/2015/564095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/24/2015] [Accepted: 01/24/2015] [Indexed: 11/17/2022]
Abstract
Background. Parkinson's disease is a neurodegenerative disease in elder people, pathophysiologic basis of which is the severe deficiency of dopamine in the striatum. The purpose of the present study was to evaluate the neuroprotective effect of low-frequency rTMS on Parkinson's disease in model mice. Methods. The effects of low-frequency rTMS on the motor function, cortex excitability, neurochemistry, and neurohistopathology of MPTP-induced Parkinson's disease mice were investigated through behavioral detection, electrophysiologic technique, high performance liquid chromatography-electrochemical detection, immunohistochemical staining, and western blot. Results. Low-frequency rTMS could improve the motor coordination impairment of Parkinson's disease mice: the resting motor threshold significantly decreased in the Parkinson's disease mice; the degeneration of nigral dopaminergic neuron and the expression of tyrosine hydroxylase were significantly improved by low-frequency rTMS; moreover, the expressions of brain derived neurotrophic factor and glial cell line derived neurotrophic factor were also improved by low-frequency rTMS. Conclusions. Low-frequency rTMS had a neuroprotective effect on the nigral dopaminergic neuron which might be due to the improved expressions of brain derived neurotrophic factor and glial cell line-derived neurotrophic factor. The present study provided a theoretical basis for the application of low-frequency rTMS in the clinical treatment and recovery of Parkinson's disease.
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Olanow CW. Levodopa: effect on cell death and the natural history of Parkinson's disease. Mov Disord 2014; 30:37-44. [PMID: 25502620 DOI: 10.1002/mds.26119] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 11/17/2014] [Indexed: 11/12/2022] Open
Abstract
This review article considers the question of whether or not levodopa is toxic in Parkinson's disease (PD). l-dopa is the most effective symptomatic treatment for PD and has provided benefit for millions of patients. However, there has been a longstanding concern that l-dopa might be toxic and accelerate neuronal degeneration and clinical progression as a consequence of reactive oxygen species generated by the drug's oxidative metabolism. In vitro, l-dopa can induce degeneration of dopaminergic neurons, but it is not clear that the effects of the drug on cultured dopamine neurons reflect what happens in the PD brain. In vivo, l-dopa has not been demonstrated to have toxic effects on dopamine neurons in normal, dopamine-lesioned, or oxidatively stressed animal models, but none of these models precisely replicates the PD condition. Clinical trials have tested the effect of l-dopa on clinical progression and have not demonstrated any findings indicative of toxicity. However, the symptomatic and long-duration effects of the drug could mask ongoing neuronal degeneration. Furthermore, l-dopa induces a greater decline in imaging measures of dopaminergic function than placebo or dopamine agonists, consistent with toxicity. Pathological studies have not demonstrated evidence of accelerated loss of dopamine neurons, but prospective and properly controlled studies with stereological unbiased counting have not been performed. Thus, although there is no hard evidence to suggest that l-dopa is toxic in PD patients, the issue has not been fully resolved. It is generally recommended that physicians continue to use l-dopa, but in the lowest dose that provides satisfactory clinical control.
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Affiliation(s)
- C Warren Olanow
- Departments of Neurology and Neuroscience, Mount Sinai School of Medicine, New York, New York, USA
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Lang AE, Miyasaki J, Olanow CW, Stoessl AJ, Suchowersky O. Progress in Clinical Neurosciences: A Forum on the Early Management of Parkinson's Disease. Can J Neurol Sci 2014; 32:277-86. [PMID: 16225167 DOI: 10.1017/s0317167100004145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
ABSTRACT:There are numerous concerns related to treatment choices involving early dopaminergic therapy in Parkinson's disease. These include the effect on the underlying progression of the neurodegenerative process as well as the development of motor complications such as fluctuations and dyskinesias. A number of recent basic and clinical studies have provided new insights but have also added confusion and controversy. This report summarizes presentations and discussion dealing with these issues from a one-day symposium involving Canadian Movement Disorders neurologists.
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Affiliation(s)
- Anthony E Lang
- Division of Neurology, Department of Medicine, University of Toronto, Toronto Western Hospital, Canada
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Krismer F, Jellinger KA, Scholz SW, Seppi K, Stefanova N, Antonini A, Poewe W, Wenning GK. Multiple system atrophy as emerging template for accelerated drug discovery in α-synucleinopathies. Parkinsonism Relat Disord 2014; 20:793-9. [PMID: 24894118 PMCID: PMC4141743 DOI: 10.1016/j.parkreldis.2014.05.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 04/27/2014] [Accepted: 05/07/2014] [Indexed: 12/21/2022]
Abstract
There is evidence that the α-synucleinopathies Parkinson's disease (PD) and the Parkinson variant of multiple system atrophy (MSA-P) overlap at multiple levels. Both disorders are characterized by deposition of abnormally phosphorylated fibrillar α-synuclein within the central nervous system suggesting shared pathophysiological mechanisms. Despite the considerable clinical overlap in the early disease stages, MSA-P, in contrast to PD, is fatal and rapidly progressive. Moreover recent clinical studies have shown that surrogate markers of disease progression can be quantified easily and may reliably depict the rapid course of MSA. We therefore posit that, MSA-P may be exploited as a filter barrier in the development of disease-modifying therapeutic strategies targeting common pathophysiological mechanisms of α-synucleinopathies. This approach might reduce the number of negative phase III clinical trials, and, in turn, shift the available resources to earlier development stages, thereby increasing the number of candidate compounds validated. α-synucleinopathies overlap at multiple levels. α-synucleinopathies are characterized by an abnormal deposition of α-synuclein. Validated surrogate markers in MSA reliably monitor disease progression. MSA may serve as a template disease for other α-synucleinopathies.
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Affiliation(s)
- Florian Krismer
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
| | | | - Sonja W Scholz
- Department of Neurology, The Johns Hopkins Hospital, Baltimore, MD 21287, USA.
| | - Klaus Seppi
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
| | - Nadia Stefanova
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
| | - Angelo Antonini
- Department of Parkinson's Disease and Movement Disorders, IRCCS San Camillo, Venice, Italy.
| | - Werner Poewe
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
| | - Gregor K Wenning
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
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Nissen T, Malek N, Grosset KA, Newman EJ, Patterson J, Hadley D, Grosset DG. Baseline [(123) I]FP-CIT SPECT (DaTSCAN) severity correlates with medication use at 3 years in Parkinson's disease. Acta Neurol Scand 2014; 129:204-8. [PMID: 23962145 DOI: 10.1111/ane.12178] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND Presynaptic dopaminergic deficiency on dopamine transporter imaging supports a clinical diagnosis of Parkinson's disease and correlates with the severity of rigidity and bradykinesia. Baseline dopaminergic deficiency predicts clinical severity, but the relationship with subsequent medication use has not been reported. METHODS A randomly selected cross section of 83 Parkinson's disease (PD) patients who had [(123) I] FP-CIT SPECT at the time of clinical diagnosis was identified. Dopaminergic deficiency was graded 1, 2 or 3 with increasing severity using visual assessment and by semiquantitative analysis of putamen and caudate uptake. Antiparkinson medication usage and clinical severity by Hoehn and Yahr were noted annually to 3 years. RESULTS In 83 patients (66% male, median age 65.0 years, IQ 55.4-71.8), [(123) I]FP-CIT SPECT was grade 1 in 20 (24%), grade 2 in 53 (64%) and grade 3 in 10 patients (12%). Dopamine transporter uptake ratios were inversely associated with antiparkinson medication usage (r = -0.26, P = 0.0201) and Hoehn Yahr stage (r = -0.32, P = 0.0029) at 3 years from baseline, but there was considerable variation in drug usage in individual patients. At 3 years, patients with grade 1 scans at baseline received a median dose of 325 levodopa equivalent units (LEU) (interquartile range 175-433); grade 2 scan patients 400 LEU (interquartile range 300-635); and grade 3 scan patients 460 LEU (interquartile range 252-658). CONCLUSION The degree of reduction in presynaptic dopaminergic uptake at baseline is associated with higher antiparkinson drug dosage at follow-up, but the wide variation means that the baseline FP-CIT SPECT does not reliably predict drug use in individual cases.
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Affiliation(s)
- T. Nissen
- Department of Neurology; Klinikum Bremerhaven; Bremerhaven Germany
| | - N. Malek
- Department of Neurology; Institute of Neurological Sciences; Southern General Hospital; Glasgow UK
| | - K. A. Grosset
- Department of Neurology; Institute of Neurological Sciences; Southern General Hospital; Glasgow UK
| | - E. J. Newman
- Department of Neurology; Institute of Neurological Sciences; Southern General Hospital; Glasgow UK
| | - J. Patterson
- Department of Nuclear Medicine Physics; Institute of Neurological Sciences; Southern General Hospital; Glasgow UK
| | - D. Hadley
- Department of Neuroradiology; Institute of Neurological Sciences; Southern General Hospital; Glasgow UK
| | - D. G. Grosset
- Department of Neurology; Institute of Neurological Sciences; Southern General Hospital; Glasgow UK
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Zhu H, Chen H, Cho W, Estrada AA, Sweeney ZK. From Human Genetics to Drug Candidates: An Industrial Perspective on LRRK2 Inhibition as a Treatment for Parkinson's Disease. METHODS AND PRINCIPLES IN MEDICINAL CHEMISTRY 2013. [DOI: 10.1002/9783527677252.ch10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Asanuma M, Miyazaki I, Diaz-Corrales FJ, Shimizu M, Tanaka KI, Ogawa N. Pramipexole has ameliorating effects on levodopa-induced abnormal dopamine turnover in parkinsonian striatum and quenching effects on dopamine-semiquinone generatedin vitro. Neurol Res 2013; 27:533-9. [PMID: 15978181 DOI: 10.1179/016164105x22093] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES AND METHODS To clarify the effects of a non-ergot dopamine agonist pramipexole on levodopa-induced abnormal dopamine metabolism in the parkinsonian model, we examined striatal changes in dopamine and its metabolites after repeated administration of pramipexole and/or levodopa using 6-hydroxydopamine-lesioned hemi-parkinsonian mice. Moreover, the effects of pramipexole on dopamine-semiquinones were also accessed using an in vitro dopamine-semiquinone generating system to elucidate its neuroprotective property against dopamine quinone-induced neurotoxicity that appears as dopamine neuron-specific oxidative stress. RESULTS Combined administration of pramipexole (0.5 or 1 mg/kg/day, 7 days) selectively suppressed the levodopa-induced (50 mg/kg/day) increase of striatal dopamine turnover in the parkinsonian side, but not in the non-lesioned side. In addition to the antioxidant properties previously reported, it was clarified that pramipexole scavenged dopamine-semiquinones generated in a dose-dependent manner either in simultaneous incubation or post-incubation. DISCUSSION The neurotoxicity of dopamine quinones that appear as dopaminergic neuron-specific oxidative stress has recently been known to play a role in the pathogenesis of Parkinson's disease and neurotoxin-induced parkinsonism. Therefore, the present results revealed that pramipexole possesses neuroprotective effects against abnormal dopamine metabolism in excessively levodopa-administered parkinsonian brains and against cytotoxic dopamine quinones generated from excess dopamine, preventing consequently dopaminergic neuronal damage induced by excess dopamine or levodopa.
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Affiliation(s)
- Masato Asanuma
- Department of Brain Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
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Boll MC, Alcaraz-Zubeldia M, Rios C. Medical management of Parkinson's disease: focus on neuroprotection. Curr Neuropharmacol 2012; 9:350-9. [PMID: 22131943 PMCID: PMC3131725 DOI: 10.2174/157015911795596577] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 07/21/2010] [Accepted: 08/13/2010] [Indexed: 12/12/2022] Open
Abstract
Neuroprotection refers to the protection of neurons from excitotoxicity, oxidative stress and apoptosis as principal mechanisms of cell loss in a variety of diseases of the central nervous system. Our interest in Parkinson’s disease (PD) treatment is focused on drugs with neuroprotective properties in preclinical experiments and evidence-based efficacy in human subjects. To this date, neuroprotection has never been solidly proven in clinical trials but recent adequate markers and/or strategies to study and promote this important goal are described. A myriad of compounds with protective properties in cell cultures and animal models yield to few treatments in clinical practice. At present, markers of neuronal vitality, disease modifying effects and long term clinical stability are the elements searched for in clinical trials. This review highlights new strategies to monitor patients with PD. Currently, neuroprotection in subjects has not been solidly achieved for selegiline and pramipexole; however, a recent rasagiline trial design is showing new indications of disease course modifying effects. In neurological practice, it is of utmost importance to take into account the potential neuroprotection exerted by a treatment in conjunction with its symptomatic efficacy.
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Affiliation(s)
- Marie-Catherine Boll
- Department of Clinical Investigation in Neurology National Institute of Neurology and Neurosurgery, Mexico. D.F
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25
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Hellman AM, Morley JF, Duda JE. Disease modification in Parkinson’s disease: are we there yet with currently available therapies? Neurodegener Dis Manag 2012. [DOI: 10.2217/nmt.12.39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SUMMARY Management of Parkinson’s disease (PD) is currently based primarily on dopamine-replacement therapy for the alleviation of motor symptoms. Current medical and surgical therapies can provide long-lasting symptomatic benefit, but they do not modify progression of the disease. Research is ongoing to find a therapy that can provide neuroprotection, defined herein as preventing vulnerable neurons from dying. Studies of neuroprotection are limited by a lack of adequate biomarkers of PD progression and by the confounding symptomatic effects of many putative neuroprotective therapies. Studies have shown that levodopa prolongs life, but they have not clearly shown that it modifies disease progression. Trials of dopamine agonists have demonstrated symptomatic effect but no unequivocal neuroprotective benefits. While some studies of monamine oxidase B inhibitors have been promising, they have not conclusively proven disease modification. Exercise provides many benefits to patients with PD, may modify the progression of the disease and should be part of each patient’s treatment plan.
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Affiliation(s)
- Amy M Hellman
- Parkinson’s Disease Research, Education & Clinical Center, Philadelphia VA Medical Center and Department of Neurology, University of Pennsylvania School of Medicine, PA 19104, USA
| | - James F Morley
- Parkinson’s Disease Research, Education & Clinical Center, Philadelphia VA Medical Center and Department of Neurology, University of Pennsylvania School of Medicine, PA 19104, USA
| | - John E Duda
- Parkinson’s Disease Research, Education & Clinical Center, Philadelphia VA Medical Center and Department of Neurology, University of Pennsylvania School of Medicine, PA 19104, USA
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27
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Abstract
In the last 25 years there have been enormous advances in brain imaging. In addition to utility in diagnosis, these have led to novel insights into the pathogenesis of basal ganglia disease and the role of dopamine and the basal ganglia in normal health. The authors review highlights of this work, with a focus on advances in Parkinson's disease, the dystonias, Huntington's disease, and the role of dopamine in cognition and reward signaling. Emerging areas for future development include studies of functional connectivity, the analysis of default mode networks, studies of novel neurochemical pathways, methods to study disease pathogenesis, and the application of imaging techniques to investigate animal models of disease.
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Affiliation(s)
- A Jon Stoessl
- Pacific Parkinson's Research Centre, University of British Columbia & Vancouver Coastal Health, Vancouver, British Columbia, Canada.
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Lipski J, Nistico R, Berretta N, Guatteo E, Bernardi G, Mercuri NB. L-DOPA: a scapegoat for accelerated neurodegeneration in Parkinson's disease? Prog Neurobiol 2011; 94:389-407. [PMID: 21723913 DOI: 10.1016/j.pneurobio.2011.06.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 06/17/2011] [Accepted: 06/17/2011] [Indexed: 12/21/2022]
Abstract
There is consensus that amelioration of the motor symptoms of Parkinson's disease is most effective with L-DOPA (levodopa). However, this necessary therapeutic step is biased by an enduring belief that L-DOPA is toxic to the remaining substantia nigra dopaminergic neurons by itself, or by specific metabolites such as dopamine. The concept of L-DOPA toxicity originated from pre-clinical studies conducted mainly in cell culture, demonstrating that L-DOPA or its derivatives damage dopaminergic neurons due to oxidative stress and other mechanisms. However, the in vitro data remain controversial as some studies showed neuroprotective, rather than toxic action of the drug. The relevance of this debate needs to be considered in the context of the studies conducted on animals and in clinical trials that do not provide convincing evidence for L-DOPA toxicity in vivo. This review presents the current views on the pathophysiology of Parkinson's disease, focusing on mitochondrial dysfunction and oxidative/proteolytic stress, the factors that can be affected by L-DOPA or its metabolites. We then critically discuss the evidence supporting the two opposing views on the effects of L-DOPA in vitro, as well as the animal and human data. We also address the problem of inadequate experimental models used in these studies. L-DOPA remains the symptomatic 'hero' of Parkinson's disease. Whether it contributes to degeneration of nigral dopaminergic neurons, or is a 'scapegoat' for explaining undesirable or unexpected effects of the treatment, remains a hotly debated topic.
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Affiliation(s)
- Janusz Lipski
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd., Auckland 1142, New Zealand.
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Clarke CE, Patel S, Ives N, Rick C, Wheatley K, Gray R. Should treatment for Parkinson's disease start immediately on diagnosis or delayed until functional disability develops? Mov Disord 2011; 26:1187-93. [DOI: 10.1002/mds.23519] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 08/20/2010] [Accepted: 10/13/2010] [Indexed: 12/14/2022] Open
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Ahlskog JE. Seniors with Parkinson's disease: initial medical treatment. J Clin Neurol 2011; 6:159-66. [PMID: 21264196 PMCID: PMC3024520 DOI: 10.3988/jcn.2010.6.4.159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 07/13/2010] [Accepted: 07/13/2010] [Indexed: 11/17/2022] Open
Abstract
Parkinson's disease most often presents after age 60, and patients in this age group are best managed with levodopa therapy as the primary treatment modality. Unlike young-onset parkinsonism (onset <age 40), this older age group is much less prone to subsequent development of levodopa responsive instability (dyskinesias, fluctuations). When these problems do occur in seniors, they usually can be managed by medication adjustments. The treatment goal is to keep patients active and engaged; levodopa dosage should be guided by the patients' responses and not arbitrarily limited to low doses, which may compromise patients' lives.
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Affiliation(s)
- J Eric Ahlskog
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
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Fernagut PO, Li Q, Dovero S, Chan P, Wu T, Ravenscroft P, Hill M, Chen Z, Bezard E. Dopamine transporter binding is unaffected by L-DOPA administration in normal and MPTP-treated monkeys. PLoS One 2010; 5:e14053. [PMID: 21124922 PMCID: PMC2989907 DOI: 10.1371/journal.pone.0014053] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 10/21/2010] [Indexed: 12/04/2022] Open
Abstract
Background Radiotracer imaging of the presynaptic nigrostriatal dopaminergic system is used to assess disease progression in Parkinson's disease (PD) and may provide a useful adjunct to clinical assessment during therapeutic trials of potential neuroprotective agents. Several clinical trials comparing dopamine agonists to L-DOPA or early vs. late L-DOPA have revealed differences between clinical assessment and imaging of the presynaptic dopaminergic system, hence questioning the comparability of these measures as neuroprotection outcome variables. Thus, results of these studies may have been affected by factors other than the primary biological process investigated. Methodology/Principal Findings We tested the possibility that L-DOPA might interfere with DAT binding. Post-mortem DAT binding was conducted in normal and MPTP-treated macaque monkeys that were administered L-DOPA, acutely or chronically. In parallel, DAT SPECT was conducted in MPTP-treated animals that were administered chronic L-DOPA. [99mTc]TRODAT-1 SPECT binding was similarly reduced in all MPTP monkeys regardless of L-DOPA treatment. L-DOPA had no significant effect on post-mortem DAT binding either in saline or in MPTP-lesioned animals. Conclusions/Significance These data indicate that L-DOPA does not induce modifications of DAT expression detectable by SPECT of by DAT binding autoradiography, suggesting that differences between clinical assessment and radiotracer imaging in clinical trials may not be specifically related to L-DOPA treatment.
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Affiliation(s)
- Pierre-Olivier Fernagut
- Université Victor Segalen-Bordeaux 2, Centre National de la Recherche Scientifique, Bordeaux Institute of Neuroscience, UMR 5227, Bordeaux, France.
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Abstract
The dopamine transporter (DAT) is responsible for clearance of dopamine from the synaptic cleft after its release. Imaging DAT availability provides a measure of dopamine terminal function and a method for detecting striatal dopamine deficiency states present in idiopathic Parkinson’s disease and atypical neurodegenerative Parkinsonian disorders such as multiple system atrophy and progressive supranuclear palsy. DAT imaging with PET or single photon emission computed tomography can be used to support a diagnosis of dopamine-deficient parkinsonism in cases where this is suspected and rationalize the use of dopaminergic agents as therapy. It can also detect subclinical dopaminergic dysfunction when present in subjects at risk of Parkinson’s disease, such as relatives of patients, susceptibility gene mutation carriers, and subjects with late-onset hyposmia or sleep disorders. Finally, the presence of normal DAT availability on imaging can help exclude nondopamine-deficient syndromes, such as dystonic and severe essential tremors, drug-induced and psychogenic parkinsonism that, on occasion, mimic Parkinson’s disease.
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Affiliation(s)
- David J Brooks
- Department of Medicine, Imperial College London, Cyclotron Building, Hammersmith Hospital, Du Cane Road, W12 0NN, UK
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Antonini A, Barone P, Ceravolo R, Fabbrini G, Tinazzi M, Abbruzzese G. Role of pramipexole in the management of Parkinson's disease. CNS Drugs 2010; 24:829-41. [PMID: 20839895 DOI: 10.2165/11585090-000000000-00000] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The non-ergot dopamine agonist pramipexole is currently indicated for the treatment of the signs and symptoms of idiopathic Parkinson's disease and for the treatment of moderate-to-severe primary restless legs syndrome. A new extended-release formulation of pramipexole has now also been launched in Europe and the US to improve ease of use, compliance and provide a more continuous therapeutic effect over 24 hours. Before initiating any treatment, the benefit-risk ratio to the individual patient must be considered. For pramipexole in the treatment of Parkinson's disease, this means taking into account the available evidence regarding its symptomatic efficacy, effect on delaying long-term levodopa-related motor complications, beneficial effect on non-motor symptoms such as depression, and its safety and tolerability profile. Studies have shown that pramipexole is effective as monotherapy in early Parkinson's disease and as adjunctive therapy in advanced disease. Trials further suggest that the benefits of pramipexole may extend beyond the relief of motor symptoms (akinesia, rigidity and tremor at rest) to the amelioration of depressive symptoms in Parkinson's disease. Pramipexole is generally well tolerated; however, compared with levodopa treatment, pramipexole is associated with a higher rate of some dopaminergic adverse effects.
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Affiliation(s)
- Angelo Antonini
- Department for Parkinson Disease, IRCCS San Camillo, Venice, Italy.
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Levodopa and pramipexole effects on presynaptic dopamine PET markers and estimated dopamine release. Eur J Nucl Med Mol Imaging 2010; 37:2364-70. [DOI: 10.1007/s00259-010-1581-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 07/23/2010] [Indexed: 02/06/2023]
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Abstract
Parkinson's disease (PD) is characterised by the progressive degeneration of dopaminergic nigro-striatal neurons and severe striatal dopaminergic deficiency, leading to bradykinesia. Levodopa was the first drug used for PD treatment and is still considered the most useful weapon for the control of PD symptoms. However, levodopa treatment induces motor complications, which is considered as a major problem as the disease progresses. Dopamine agonists, catechol-O-methyltransferase inhibitors and monoamine oxidase B inhibitors are some more recently developed drug categories which are expected to have a more favourable effect on motor complications. The choice of the best initial treatment in PD remains a controversial matter. Early therapeutic decisions in PD should balance the need for efficient short-term symptom control against long-term complication profile. The individualisation of the treatment seems to be the key for the best approach of early PD patients.
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Affiliation(s)
- S Tsouli
- Department of Neurology, University Hospital of Ioannina, Ioannina, Greece.
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Ahlskog JE, Uitti RJ. Rasagiline, Parkinson neuroprotection, and delayed-start trials: still no satisfaction? Neurology 2010; 74:1143-8. [PMID: 20368634 DOI: 10.1212/wnl.0b013e3181d7d8e2] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Rasagiline has been studied as a Parkinson disease (PD) neuroprotective agent in 2 major clinical trials, utilizing the delayed-start design in an attempt to separate symptomatic drug benefits from a disease-modifying effect. The ostensibly positive outcomes of these studies, however, are obscured by potential confounding factors that seem intrinsic to this trial design, including 1) very small changes in clinical outcome measures that could easily be overshadowed by other influences; 2) probable incomplete blinding to study end; 3) subjective components of the Unified Parkinson's Disease Rating Scale (UPDRS) scoring system; and 4) practice influences from repeated scoring. Interpretation of the recent Attenuation of Disease Progression with Azilect Given Once-daily (ADAGIO) trials is especially problematic given 1) divergent results with the 2 symptomatically beneficial doses and 2) variability in UPDRS scores with active rasagiline, which was twice the magnitude of the major finding of the study. These studies further illustrate the difficulty in documenting a disease-modifying effect when considering a PD drug with symptomatic benefit.
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Affiliation(s)
- J Eric Ahlskog
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA.
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Trials of neuroprotective therapies for Parkinson's disease: problems and limitations. Parkinsonism Relat Disord 2010; 16:365-9. [PMID: 20471298 DOI: 10.1016/j.parkreldis.2010.04.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 04/12/2010] [Accepted: 04/18/2010] [Indexed: 11/21/2022]
Abstract
Since the initial results of the DATATOP study, considerable effort has been devoted over the past 20 years to test neuroprotective therapies for Parkinson's disease (PD). Two trials (CALM-PD-CIT and REAL-PET studies) used neuroimaging dopamine changes as a surrogate marker for PD progression, and concluded that pramipexole and ropinirole could have a neuroprotective effect compared to levodopa. However, it should be recognized that all the presynaptic dopamine markers currently available for SPECT and PET studies are potentially subject to regulatory changes. Consequently, the results of these two trials can also be interpreted in terms of drug-related differences in dopamine regulation. More recently, the delayed-start design was applied to test whether rasagiline could have a neuroprotective effect in PD (ADAGIO study). Unfortunately, a major limitation of the delayed-start design is that, whenever the active treatment has a symptomatic effect, the blinding can be broken. This can lead to unequally-distributed placebo responses during phase 2, and is also a potential source of raters' biases. None of the trials on neuroprotective therapies for PD has yet provided solid evidence for neuroprotection.
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Kuriakose R, Stoessl AJ. Imaging the nigrostriatal system to monitor disease progression and treatment-induced complications. PROGRESS IN BRAIN RESEARCH 2010; 184:177-92. [PMID: 20887875 DOI: 10.1016/s0079-6123(10)84009-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Radiotracer imaging (RTI) techniques such as positron emission tomography (PET) allow the in vivo assessment of nigrostriatal DA function in Parkinson's disease and have provided valuable insights into the mechanisms of nigrostriatal degeneration and the consequent compensatory changes. Moreover, functional imaging serves as an excellent tool in the assessment of the progression of PD and the evolution of treatment-related complications. However, various studies have shown discordance between clinical progression of PD and nigrostriatal degeneration estimated by PET or SPECT, and no RTI technique can be reliably used as a biomarker for progression of PD. Presynaptic dopaminergic imaging has consistently demonstrated an anterior-posterior gradient of dopaminergic dysfunction predominantly affecting the putamen, with side-to-side asymmetry in tracer binding. Dopaminergic hypofunction in the striatum follows a negative exponential pattern with the fastest rate of decline in early disease. Evaluation of central pharmacokinetics of levodopa action by PET has demonstrated the role of increased synaptic dopamine turnover and downregulation of the dopamine transporter in the pathophysiology of levodopa-induced dyskinesias. In PD with behavioral complications such as impulse control disorders, increased levels of dopamine release have been observed in the ventral striatum during performance of a positive reward task, as well as loss of deactivation in orbitofrontal cortex in response to negative reward prediction errors. This suggests that there is a pathologically heightened "reward" response in the ventral striatum together with loss of the capacity to respond to negative outcomes. Overall, functional imaging with PET is an excellent tool for understanding the disease and its complications; however, caution must be applied in interpretation of the results.
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Affiliation(s)
- Renju Kuriakose
- Pacific Parkinson’s Research Centre, University of British Columbia and Vancouver Coastal Health, Vancouver, BC, Canada
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Antonini A, Tolosa E, Mizuno Y, Yamamoto M, Poewe WH. A reassessment of risks and benefits of dopamine agonists in Parkinson's disease. Lancet Neurol 2009; 8:929-37. [DOI: 10.1016/s1474-4422(09)70225-x] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Olanow CW, Hauser RA, Jankovic J, Langston W, Lang A, Poewe W, Tolosa E, Stocchi F, Melamed E, Eyal E, Rascol O. A randomized, double-blind, placebo-controlled, delayed start study to assess rasagiline as a disease modifying therapy in Parkinson's disease (the ADAGIO study): rationale, design, and baseline characteristics. Mov Disord 2009; 23:2194-201. [PMID: 18932271 DOI: 10.1002/mds.22218] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A neuroprotective therapy is the single most important unmet medical need in Parkinson's disease. Several promising agents in the laboratory have been tested in the clinic, but none has been established in clinical trials to have a disease modifying effect despite positive results because of potential confounding symptomatic or pharmacologic effects. The delayed start design was developed to try to avoid a symptomatic confound when testing a putative neuroprotective therapy. In this study design, patients are randomly assigned to study drug or placebo in the first phase of the study, and both groups receive the active drug in the second phase. If benefits seen at the end of phase I persist through the end of phase II, they cannot be readily explained by a symptomatic effect (as patients in both groups are receiving the same medication) and benefits in the early start group must relate to the early initiation of the treatment. Although the precise mechanism responsible for such an effect can be debated, positive results in a delayed start study indicate that patients who receive early treatment have a better outcome than those where the treatment is delayed. We are using the delayed start design to assess the potential disease modifying effects of rasagiline in a prospective double blind controlled trial (the ADAGIO study). We here describe the rationale for the study and baseline characteristics of the 1,176 patients who have been enrolled into the trial.
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Affiliation(s)
- C Warren Olanow
- Department of Neurology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Olanow CW, Kieburtz K, Schapira AHV. Why have we failed to achieve neuroprotection in Parkinson's disease? Ann Neurol 2009; 64 Suppl 2:S101-10. [PMID: 19127580 DOI: 10.1002/ana.21461] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The development of a neuroprotective therapy that slows, stops, or reverses neurodegeneration in Parkinson's disease (PD) is the single most important unresolved issue in the management of this disorder. Current therapies provide effective control of symptoms, particularly in the early stages of the disease, but disease progression is associated with the development of "nondopaminergic" features such as postural instability, falling, and dementia that are not adequately controlled with existing medications. There are many promising candidate neuroprotective agents based on pathological and laboratory studies, but to date, it has not been possible to determine that any drug has a disease-modifying effect in PD. Obstacles to the development of a neuroprotective therapy in PD include: (1) uncertainty as to the precise cause of cell death in PD and what to target; (2) the lack of an animal model of PD that precisely reflects the etiopathogenesis of the disease, the pattern of dopaminergic and nondopaminergic pathology, and its chronic, progressive nature; (3) determination of the correct dose to use in clinical trials; and (4) delineation of a clinical end point that is an accurate measure of the underlying disease and is not confounded by potential symptomatic effects of a study intervention. New developments in understanding the cause of the disease, in the development of animal models of PD, and in clinical trial methodology will hopefully hasten the resolution of these problems.
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Affiliation(s)
- C Warren Olanow
- Department of Neurology, Mount Sinai School of Medicine, New York, USA.
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Marek K, Jennings D, Tamagnan G, Seibyl J. Biomarkers for Parkinson's [corrected] disease: tools to assess Parkinson's disease onset and progression. Ann Neurol 2009; 64 Suppl 2:S111-21. [PMID: 19127587 DOI: 10.1002/ana.21602] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Reliable and well-validated biomarkers for PD to identify individuals "at risk" before motor symptoms, accurately diagnose individuals at the threshold of clinical PD, and monitor PD progression throughout its course would dramatically accelerate research into both PD cause and therapeutics. Biomarkers offer the potential to provide a window onto disease mechanism, potentially generating therapeutic targets for disease. In particular, biomarkers enable investigation of the premotor period of PD before typical symptoms are manifest, but while degeneration has already begun. Given the multiple genetic causes for PD already identified, the marked variability in the loss of dopaminergic markers measured by imaging at motor symptom onset and the clear heterogeneity of clinical symptoms in PD onset and clinical progression, it is likely many biomarkers with a focus ranging from clinical symptoms to PD pathobiology to molecular genetic mechanisms will be necessary to fully map PD risk and progression. Biomarkers are also critical in new drug development for PD, both in early validation studies to assess drug dosing and to determine drug penetrance into the brain, and in later efficacy studies to complement PD clinical outcomes. During the past two decades, much progress has been made in identifying and assessing PD biomarkers, but as yet, no fully validated biomarker for PD is currently available. Nonetheless, there is increasing evidence that molecular genetics, focused -omic (proteomic, metabolomic, and transcriptomic) assessment of blood and cerebrospinal fluid, and advanced in vivo brain imaging will provide critical clues to assist in the diagnosis and medical management of PD patients.
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Affiliation(s)
- Kenneth Marek
- Institute for Neurodegenerative Disorders, New Haven, CT, USA.
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Schapira AHV, Olanow CW. Drug selection and timing of initiation of treatment in early Parkinson's disease. Ann Neurol 2009; 64 Suppl 2:S47-55. [DOI: 10.1002/ana.21460] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Shahed J, Jankovic J. Internet dyskinesias in Parkinson’s disease. Mov Disord 2008. [DOI: 10.3109/9780203008454-68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Schapira AH. The clinical relevance of levodopa toxicity in the treatment of Parkinson's disease. Mov Disord 2008; 23 Suppl 3:S515-20. [DOI: 10.1002/mds.22146] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Abstract
Slowing or aborting the progress of neurodegeneration in Parkinson's disease (PD) remains the most important unmet need of this disorder. There are several recent developments in trial design and also in drugs under investigation for possible neuroprotective effect. Emphasis has been placed on clinical as opposed to imaging end-points and these include change in a clinical rating scale, e.g. United Parkinson's disease Rating Scale (UPDRS), or time to additional therapy. The introduction of the delayed-start, or wash-in, trial design adds an additional dimension to drug evaluation for neuroprotection. Compounds that have been recently tested in clinical trial include the monoamine oxidase-B inhibitor rasagiline, the anti-apoptotic agents TCH346 and CEP1347, and the promitochondrial agent creatine. The dopamine agonists have been evaluated for a neuroprotective effect using imaging end-points. Perhaps the most important and simplest concept for neuroprotection has been the theory that early dopaminergic support for the degenerating dopaminergic system per se provides significant long-term clinical benefit for PD patients.
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Affiliation(s)
- A H V Schapira
- University Department of Clinical Neurosciences, Institute of Neurology, University College London, London, UK.
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Scherfler C, Schwarz J, Antonini A, Grosset D, Valldeoriola F, Marek K, Oertel W, Tolosa E, Lees AJ, Poewe W. Role of DAT-SPECT in the diagnostic work up of parkinsonism. Mov Disord 2008; 22:1229-38. [PMID: 17486648 DOI: 10.1002/mds.21505] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The diagnosis of idiopathic Parkinson's disease (PD) can be achieved with high degrees of accuracy in cases with full expression of classical clinical features. However, diagnostic uncertainty remains in early disease with subtle or ambiguous signs. Functional imaging has been suggested to increase the diagnostic yield in parkinsonian syndromes with uncertain clinical classification. Loss of striatal dopamine nerve terminal function, a hallmark of neurodegenerative parkinsonism, is strongly related to decreases of dopamine transporter (DAT) density, which can be measured by single photon emission computed tomography (SPECT). The use of DAT-SPECT facilitates the differential diagnosis in patients with isolated tremor symptoms not fulfilling PD or essential tremor criteria, drug-induced, psychogenic and vascular parkinsonism as well as dementia when associated with parkinsonism. This review addresses the value of DAT-SPECT in early differential diagnosis, and its potential as a screening tool for subjects at risk of developing PD as well as issues around the assessment of disease progression.
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Arias-Carrión O. Basic mechanisms of rTMS: Implications in Parkinson's disease. Int Arch Med 2008; 1:2. [PMID: 18471317 PMCID: PMC2375865 DOI: 10.1186/1755-7682-1-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Accepted: 04/15/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Basic and clinical research suggests a potential role for repetitive transcranial magnetic stimulation (rTMS) in the treatment of Parkinson's disease. However, compared to the growing number of clinical studies on its putative therapeutic properties, the studies on the basic mechanisms of rTMS are surprisingly scarce. RESULTS Animal studies have broadened our understanding of how rTMS affects brain circuits and the causal chain in brain-behavior relationships. The observed changes are thought to be to neurotransmitter release, transsynaptic efficiency, signaling pathways and gene transcription. Furthermore, recent studies suggest that rTMS induces neurogenesis, neuronal viability and secretion of neuroprotective molecules. CONCLUSION The mechanisms underlying the disease-modifying effects of these and related rTMS in animals are the principle subject of the current review. The possible applications for treatment of Parkinson's disease are discussed.
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