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Chahine LM, Simuni T. Role of novel endpoints and evaluations of response in Parkinson disease. HANDBOOK OF CLINICAL NEUROLOGY 2023; 193:325-345. [PMID: 36803820 DOI: 10.1016/b978-0-323-85555-6.00010-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
With progress in our understanding of Parkinson disease (PD) and other neurodegenerative disorders, from clinical features to imaging, genetic, and molecular characterization comes the opportunity to refine and revise how we measure these diseases and what outcome measures are used as endpoints in clinical trials. While several rater-, patient-, and milestone-based outcomes for PD exist that may serve as clinical trial endpoints, there remains an unmet need for endpoints that are clinically meaningful, patient centric while also being more objective and quantitative, less susceptible to effects of symptomatic therapy (for disease-modification trials), and that can be measured over a short period and yet accurately represent longer-term outcomes. Several novel outcomes that may be used as endpoints in PD clinical trials are in development, including digital measures of signs and symptoms, as well a growing array of imaging and biospecimen biomarkers. This chapter provides an overview of the state of PD outcome measures as of 2022, including considerations for selection of clinical trial endpoints in PD, advantages and limitations of existing measures, and emerging potential novel endpoints.
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Affiliation(s)
- Lana M Chahine
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Tanya Simuni
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States.
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2
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Abstract
Functional neuroimaging using techniques such as positron emission tomography (PET) and single photon emission computerised tomography (SPECT) provide a direct in vivo assessment of the expression and function of neuroreceptors, transporters and enzymes. This article examines the technical aspects of molecular imaging and the application of those techniques in drug development.
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3
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Harun R, Hare KM, Brough EM, Munoz MJ, Grassi CM, Torres GE, Grace AA, Wagner AK. Fast-scan cyclic voltammetry demonstrates that L-DOPA produces dose-dependent, regionally selective bimodal effects on striatal dopamine kinetics in vivo. J Neurochem 2016; 136:1270-1283. [PMID: 26611352 PMCID: PMC4884169 DOI: 10.1111/jnc.13444] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 11/29/2022]
Abstract
Parkinson's disease (PD) is a debilitating condition that is caused by a relatively specific degeneration of dopaminergic (DAergic) neurons of the substantia nigra pars compacta. L-DOPA was introduced as a viable treatment option for PD over 40 years ago and still remains the most common and effective therapy for PD. Though the effects of L-DOPA to augment striatal DA production are well known, little is actually known about how L-DOPA alters the kinetics of DA neurotransmission that contribute to its beneficial and adverse effects. In this study, we examined the effects of L-DOPA administration (50 mg/kg carbidopa + 0, 100, and 250 mg/kg L-DOPA) on regional electrically stimulated DA response kinetics using fast-scan cyclic voltammetry in anesthetized rats. We demonstrate that L-DOPA enhances DA release in both the dorsal striatum (D-STR) and nucleus accumbens (NAc), but surprisingly causes a delayed inhibition of release in the D-STR. In both regions, L-DOPA progressively attenuated reuptake kinetics, predominantly through a decrease in Vmax . These findings have important implications on understanding the pharmacodynamics of L-DOPA, which may be informative for understanding its therapeutic effects and also common side effects like L-DOPA-induced dyskinesias (LID). L-DOPA is commonly used to treat Parkinsonian symptoms, but little is known about how it affects presynaptic DA neurotransmission. Using in vivo fast-scan cyclic voltammetry, we show L-DOPA inhibits DA reuptake in a region-specific and dose-dependent manner, and L-DOPA has paradoxical effects on release. These findings may be important when considering mechanisms for L-DOPA's therapeutic benefits and adverse side-effects.
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Affiliation(s)
- Rashed Harun
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
- Safar Center for Resuscitation Research, Pittsburgh, Pennsylvania, USA
| | - Kristin M Hare
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Elizabeth M Brough
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
- Safar Center for Resuscitation Research, Pittsburgh, Pennsylvania, USA
| | - Miranda J Munoz
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Biological Sciences, Carnegie Mellon University, Mellon College of Science, Pittsburgh, Pennsylvania, USA
| | - Christine M Grassi
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Gonzalo E Torres
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Neurobiology, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Anthony A Grace
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Departments of Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Amy K Wagner
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA
- Safar Center for Resuscitation Research, Pittsburgh, Pennsylvania, USA
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Ciarmiello A, Giovacchini G, Guidotti C, Meniconi M, Lazzeri P, Carabelli E, Mansi L, Mariani G, Volterrani D, Del Sette M. Weighted registration of123I-FP-CIT SPECT images improves accuracy of binding potential estimates in pathologically low striatal uptake. J Cell Physiol 2013; 228:2086-94. [DOI: 10.1002/jcp.24378] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 03/25/2013] [Indexed: 11/06/2022]
Affiliation(s)
| | | | - Claudio Guidotti
- Nuclear Medicine Department; Hospital S. Andrea; La Spezia; Italy
| | - Martina Meniconi
- Nuclear Medicine Department; Hospital S. Andrea; La Spezia; Italy
| | - Patrizia Lazzeri
- Nuclear Medicine Department; Hospital S. Andrea; La Spezia; Italy
| | | | - Luigi Mansi
- Nuclear Medicine; Second University of Naples; Napoli; Italy
| | - Giuliano Mariani
- Regional Center of Nuclear Medicine; University of Pisa Medical School; Pisa; Italy
| | - Duccio Volterrani
- Regional Center of Nuclear Medicine; University of Pisa Medical School; Pisa; Italy
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Lindsley CW, Hopkins CR. Metabotropic glutamate receptor 4 (mGlu4)-positive allosteric modulators for the treatment of Parkinson's disease: historical perspective and review of the patent literature. Expert Opin Ther Pat 2012; 22:461-81. [PMID: 22506633 DOI: 10.1517/13543776.2012.679437] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Metabotropic glutamate receptor 4 (mGlu(4)) is a group III GPCR and has been demonstrated to play a major role in a number of therapeutic areas within the CNS. As the orthosteric site of all glutamate receptors is highly conserved, modulating mGlu(4) via allosteric modulation has emerged as a very attractive mode-of-action and has been validated preclinically in a number of animal models for Parkinson's disease, anxiety, pain, and neuroinflammation. AREAS COVERED In this review, the patent literature for mGlu(4)-positive allosteric modulators over the past 4 years will be provided. Patents from all companies are discussed and an overview of the chemical matter and relevant biological properties will be given. EXPERT OPINION Although there has yet to be an mGlu(4)-positive allosteric modulator progressed into clinical trials, there is a wealth of preclinical data from the primary literature that shows the promise of this emerging target. A number of academic and industry laboratories have recently published exciting patent data covering a multitude of chemical matter. Positive allosteric modulation of mGlu(4) remains one of the more attractive non-dopaminergic therapies for Parkinson's disease, as well as emerging data for other indications such as pain, neuroinflammation, schizophrenia and diabetes, which could potentially make mGlu(4) a significant therapeutic target going forward.
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Affiliation(s)
- Craig W Lindsley
- Vanderbilt University, Vanderbilt University Medical Center, Vanderbilt Center for Neuroscience Drug Discovery, Department of Chemistry, Nashville, TN 37232, USA
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Jones CK, Engers DW, Thompson AD, Field JR, Blobaum AL, Lindsley SR, Zhou Y, Gogliotti RD, Jadhav S, Zamorano R, Bogenpohl J, Smith Y, Morrison R, Daniels JS, Weaver CD, Conn PJ, Lindsley CW, Niswender CM, Hopkins CR. Discovery, synthesis, and structure-activity relationship development of a series of N-4-(2,5-dioxopyrrolidin-1-yl)phenylpicolinamides (VU0400195, ML182): characterization of a novel positive allosteric modulator of the metabotropic glutamate receptor 4 (mGlu(4)) with oral efficacy in an antiparkinsonian animal model. J Med Chem 2011; 54:7639-47. [PMID: 21966889 DOI: 10.1021/jm200956q] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There is an increasing amount of literature data showing the positive effects on preclinical antiparkinsonian rodent models with selective positive allosteric modulators of metabotropic glutamate receptor 4 (mGlu(4)). However, most of the data generated utilize compounds that have not been optimized for druglike properties, and as a consequence, they exhibit poor pharmacokinetic properties and thus do not cross the blood-brain barrier. Herein, we report on a series of N-4-(2,5-dioxopyrrolidin-1-yl)phenylpicolinamides with improved PK properties with excellent potency and selectivity as well as improved brain exposure in rodents. Finally, ML182 was shown to be orally active in the haloperidol induced catalepsy model, a well-established antiparkinsonian model.
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Affiliation(s)
- Carrie K Jones
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, 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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Tasaki Y, Omura T, Yamada T, Ohkubo T, Suno M, Iida S, Sakaguchi T, Asari M, Shimizu K, Matsubara K. Meloxicam protects cell damage from 1-methyl-4-phenyl pyridinium toxicity via the phosphatidylinositol 3-kinase/Akt pathway in human dopaminergic neuroblastoma SH-SY5Y cells. Brain Res 2010; 1344:25-33. [DOI: 10.1016/j.brainres.2010.04.085] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2009] [Revised: 04/09/2010] [Accepted: 04/30/2010] [Indexed: 10/19/2022]
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Abstract
Despite all recent advances in symptomatic therapy Parkinson's disease (PD) continues to be a relentlessly progressive neurodegenerative disorder. Therefore therapies that will slow or hold disease progression are a major medical unmet need in PD. Clinical measures of disease progression that have been used in disease modification trials so far have focused on indices of progression of cardinal motor features like bradykinesia, rigidity, and tremor as captured by the UPDRS and the emerging need for effective dopaminergic symptomatic therapy. Progression of global disability in PD, however, is driven by additional factors beyond progressive nigrostriatal denervation leading to increasing severity of cardinal motor features. Progressive pathology in extranigral sites in the brain or peripheral autonomic nervous system contribute to poorly levodopa responsive motor symptoms like postural instability, freezing and falls or nonmotor symptoms. In addition treatment-induced motor complications also impact on PD disability. Although it is widely accepted that clinical progression of PD is multidimensional and in addition includes effects of aging, there is no consensus how to best implement more clinically meaningful endpoints for disease progression trials that would reflect these complex interactions impacting on the evolution of global disability in PD. There is an urgent need for biomarkers for disease progression that would faithfully reflect advancing neurodegeneration and resulted clinical disability in PD and that could be used in shorter term clinical trials testing putative disease modifying agents.
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Affiliation(s)
- Werner Poewe
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
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Antoniades CA, Barker RA. The search for biomarkers in Parkinson's disease: a critical review. Expert Rev Neurother 2009; 8:1841-52. [PMID: 19086880 DOI: 10.1586/14737175.8.12.1841] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder that primarily presents with features of bradykinesia, rigidity and tremor, and has, as part of its core pathology, the degeneration of dopaminergic neurons in the substantia nigra pars compacta. There is a great need for the development of a reliable diagnostic tool to improve promptness of diagnosis, definition of disease subtypes, and to monitor disease progression and demonstrate treatment efficacy in the case of disease modifying therapies. Current biomarkers range from objective clinical tools, to neuroimaging, to 'wet' markers involving blood and cerebrospinal fluid. To date, all candidate biomarkers for PD have failed to be developed into a clinically useful tool. Ideally, a combination of sensitive markers will be needed, not only to predict the onset of PD, but also to help in subtype classification and to follow progression. Here, we critically review various PD biomarker studies.
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Affiliation(s)
- Chrystalina A Antoniades
- Cambridge Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Cambridge CB22PY, UK.
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11
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Abstract
Treatments with potential neuroprotective capability for Parkinson's disease (PD) have been investigated in randomized, controlled, clinical trials and other studies since the mid-1980s. Although promising leads have arisen, no therapy has been proven to halt or slow disease progression. Several large-scale studies have highlighted progress in methodology, as well as the frustrations of translating laboratory science to practical applications. This review summarizes findings from clinical trials with several classes of compounds, including monoamine oxidase-B inhibitors (selegiline, lazabemide, rasagiline), dopaminergic drugs (ropinirole, pramipexole, levodopa), antioxidant strategies (alpha-tocopherol), mitochondrial energy enhancers (coenzyme Q(10), creatine), antiapoptotic agents (TCH346, minocycline, CEP-1347), and antiglutamatergic compounds (riluzole). Beyond small-molecule pharmacology, gene therapy approaches, such as delivering neurotrophic substances (e.g., neurturin) by viral vector, are the next generation of treatment options.
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Affiliation(s)
- Peter A LeWitt
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, USA.
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12
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Optimizing long-term therapy for Parkinson disease: levodopa, dopamine agonists, and treatment-associated dyskinesia. Clin Neuropharmacol 2008; 31:51-6. [PMID: 18303491 DOI: 10.1097/wnf.0b013e318065b088] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The treatment of Parkinson disease (PD) involves pharmacological treatment, often with levodopa or dopamine agonists, to restore the dopaminergic deficit associated with parkinsonian symptoms. Either agent provides symptom relief that becomes less effective in the course of PD, and switching or combining these agents or adding other therapies becomes necessary for symptom control. In an effort to delay the development of motor complications, dopamine agonists are often used in the initial treatment of PD. However, control of PD symptoms is superior with levodopa. Moreover, dopamine agonists are less well tolerated overall and are associated with a number of rare but serious adverse effects. In the long-term management of PD, treatment-associated dyskinesia often becomes sufficiently troublesome as to compromise the effective dosing of antiparkinsonian medication. More effective strategies for managing dyskinesia are needed.
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Colebrooke RE, Humby T, Lynch PJ, McGowan DP, Xia J, Emson PC. Age-related decline in striatal dopamine content and motor performance occurs in the absence of nigral cell loss in a genetic mouse model of Parkinson's disease. Eur J Neurosci 2007; 24:2622-30. [PMID: 17100850 DOI: 10.1111/j.1460-9568.2006.05143.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dopamine cytotoxicity is thought to contribute towards the selective loss of substantia nigra pars compacta dopamine neurons and disease progression in Parkinson's disease. However, the long-term toxicity of dopamine in vivo has not previously been established. The vesicular monoamine transporter 2 (VMAT2) sequesters monoamines into synaptic vesicles, a process that, in addition to being important in normal transmission, may also act to keep intracellular levels of monoamine neurotransmitters below potentially toxic thresholds. The homozygous VMAT2-hypomorphic mouse has an insertion in the VMAT2 gene (Slc18a2). Consequently, VMAT2-deficient mice (VD(-/-)) have an approximately 95% reduction in VMAT2 expression and an equivalent level of dopamine depletion in the striatum which results in moderate motor impairment. Here, we show that L-DOPA induces locomotor hyperactivity in VD(-/-) mice and reverses the deficit in motor coordination and balance as tested with the rotarod. We report that evidence for cytosolic accumulation of dopamine in substantia nigra neurons in these mice is two-fold: firstly, there is reduced phosphorylation of tyrosine hydroxylase at the residue associated with catechol feedback inhibition; and, secondly, there are increased rates of dopamine turnover at 6, 12 and 24 months of age. These animals exhibit a progressive decline in striatal monoamine levels and rotarod performance with increasing age. However, despite these data, there was no loss of nigral dopamine neurons as estimated by quantification of tyrosine hydroxylase-immunoreactive cells in the substantia nigra pars compacta of old VD(-/-) mice (24-month-old), implying that these age-dependent manifestations may be due to senescence alone.
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Affiliation(s)
- Rebecca E Colebrooke
- Laboratory of Molecular Neuroscience, The Babraham Institute, Cambridge, CB2 4AT, UK
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Nyholm D. Pharmacokinetic optimisation in the treatment of Parkinson's disease : an update. Clin Pharmacokinet 2006; 45:109-36. [PMID: 16485914 DOI: 10.2165/00003088-200645020-00001] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Pharmacotherapy for Parkinson's disease is focused on dopaminergic drugs, mainly the dopamine precursor levodopa and dopamine receptor agonists. The elimination half-life (t(1/2)) of levodopa from plasma (in combination with a decarboxylase inhibitor) of about 1.5 hours becomes more influential as the disease progresses. The long-duration of response to levodopa, which is evident in early Parkinson's disease, diminishes and after a few years of treatment motor performance is closely correlated to the fluctuating plasma concentrations of levodopa. Absorption of levodopa in the proximal small intestine depends on gastric emptying, which is erratic and may be slowed in Parkinson's disease. The effects of levodopa on motor function are dependent on gastric emptying in patients in the advanced stages of disease. The current treatment concept is continuous dopaminergic stimulation (CDS). Sustained-release formulations of levodopa may provide more stable plasma concentrations. Oral liquid formulations shorten the time to reach peak concentration and onset of effect but do not affect plasma levodopa variability. The t(1/2) of levodopa can be prolonged by adding a catechol-O-methyltransferase inhibitor (entacapone or tolcapone), which may reduce fluctuations in plasma concentrations, although both peak and trough concentrations are increased with frequent administration. Intravenous and enteral (duodenal/jejunal) infusions of levodopa yield stable plasma levodopa concentrations and motor performance. Enteral infusion is feasible on a long-term basis in patients with severe fluctuations. Among the dopamine receptor agonists the ergot derivatives bromocriptine, cabergoline, dihydroergocryptine and pergolide, and the non-ergot derivatives piribedil, pramipexole and ropinirole, have longer t(1/2) compared with levodopa. Thus, they stimulate dopamine receptors in a less pulsatile manner, yet pharmacokinetic studies of repeated doses of dopamine receptor agonists are few. Optimisation of these drugs is often performed with standardised titration schedules. Apomorphine and lisuride have short t(1/2) and are suitable for subcutaneous infusion, with results similar to those of levodopa infusion. Transdermal administration of dopamine receptor agonists such as rotigotine might be an alternative in the future. In general, initial dopamine receptor agonist monotherapy is associated with poorer motor performance and lower incidence of motor complications compared with levodopa. Buccal administration of the monoamine oxidase-B inhibitor selegiline (deprenyl) provides better absorption and less formation of metabolites compared with standard tablets. To conclude, several new drugs, formulations and routes of administration have been introduced in the treatment of Parkinson's disease during the last decade, mainly with CDS as the aim. CDS can be approached by optimising the use of dopaminergic drugs based on pharmacokinetic data.
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Affiliation(s)
- Dag Nyholm
- Department of Neuroscience, Neurology, Uppsala University Hospital, Uppsala, Sweden.
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Badarny S, Stern A, Susel Z, Honigman S, Hocherman S. Effect of ropinirole on visuo-motor test in newly diagnosed Parkinson's disease patients. Acta Neurol Scand 2006; 113:294-300. [PMID: 16629764 DOI: 10.1111/j.1600-0404.2006.00601.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The aim of this study was to assess the sensitivity of the visuo-motor test (VMT) compared with the Unified Parkinson's Disease Rating Scale (UPDRS) in newly diagnosed Parkinson's disease (PD) patients. METHODS VMT and UPDRS were carried out in 20 patients before treatment onset, 2 weeks after treatment with ropinirole 1.5 mg/day and 2 weeks following increasing the dose of ropinirole to 3.0 mg/day. RESULTS Improvement in clinical status was seen in all patients, with a mean UPDRS reduction of 16.6% following treatment with ropinirole 1.5 mg/day, and 38.9% reduction in UPDRS observed with ropinirole 3.0 mg/day. Initial improvement was not correlated with severity of PD, although further improvement with ropinirole 3.0 mg/day correlated linearly with patient's baseline UPDRS. Improvement in the ability to control the direction of the moving hand during tracing is expressed by the reduction of VMT variables following treatment. Mean VMT variables were 36.2% at baseline, 34.0% with ropinirole 1.5 mg/day and 31.7% with ropinirole 3.0 mg/day. Although changes in VMT variables were less uniform across patients, on average, it did correlate with patients UPDRS. CONCLUSIONS We suggest that VMT can be useful in the assessment of treatment effect on high-level motor planning and cognitive capabilities in newly diagnosed PD patients, added to the UPDRS which does not appropriately comply with those skills.
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Affiliation(s)
- S Badarny
- Movement Disorders Clinic, Department of Neurology, Carmel Medical Center, Haifa, Israel.
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16
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Millan MJ. Multi-target strategies for the improved treatment of depressive states: Conceptual foundations and neuronal substrates, drug discovery and therapeutic application. Pharmacol Ther 2006; 110:135-370. [PMID: 16522330 DOI: 10.1016/j.pharmthera.2005.11.006] [Citation(s) in RCA: 388] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Accepted: 11/28/2005] [Indexed: 12/20/2022]
Abstract
Major depression is a debilitating and recurrent disorder with a substantial lifetime risk and a high social cost. Depressed patients generally display co-morbid symptoms, and depression frequently accompanies other serious disorders. Currently available drugs display limited efficacy and a pronounced delay to onset of action, and all provoke distressing side effects. Cloning of the human genome has fuelled expectations that symptomatic treatment may soon become more rapid and effective, and that depressive states may ultimately be "prevented" or "cured". In pursuing these objectives, in particular for genome-derived, non-monoaminergic targets, "specificity" of drug actions is often emphasized. That is, priority is afforded to agents that interact exclusively with a single site hypothesized as critically involved in the pathogenesis and/or control of depression. Certain highly selective drugs may prove effective, and they remain indispensable in the experimental (and clinical) evaluation of the significance of novel mechanisms. However, by analogy to other multifactorial disorders, "multi-target" agents may be better adapted to the improved treatment of depressive states. Support for this contention is garnered from a broad palette of observations, ranging from mechanisms of action of adjunctive drug combinations and electroconvulsive therapy to "network theory" analysis of the etiology and management of depressive states. The review also outlines opportunities to be exploited, and challenges to be addressed, in the discovery and characterization of drugs recognizing multiple targets. Finally, a diversity of multi-target strategies is proposed for the more efficacious and rapid control of core and co-morbid symptoms of depression, together with improved tolerance relative to currently available agents.
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Affiliation(s)
- Mark J Millan
- Institut de Recherches Servier, Centre de Recherches de Croissy, Psychopharmacology Department, 125, Chemin de Ronde, 78290-Croissy/Seine, France.
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Abstract
UNLABELLED Levodopa therapy, as originally established by George Cotzias [2, 3], is the most powerful treatment for Parkinson's disease (PD). Levodopa's toxicity to neurons in vitro has raised concerns if it might hasten the progression of PD, although in vivo animal studies suggest it may be neuroprotective. OBJECTIVE To discuss the results of the ELLDOPA trial that was carried out to determine if levodopa therapy influences the rate of progression of Parkinson's disease (PD). DESIGN ELLDOPA was a multicenter, parallel-group, double-blind, dosage-ranging, randomized, controlled clinical trial. SETTING Academic movement disorders clinics at 38 sites in the United States and Canada. PATIENTS Three hundred and sixty-one patients with early PD of less than 2 years' duration who did not require symptomatic therapy. INTERVENTIONS Subjects were randomly assigned to one of four treatment groups: carbidopa/levodopa 12.5/50 mg t. i. d. (N=92), 25/100 mg t. i. d. (N=88), 50/200 mg t. i. d. (N=91), or matching placebo (N=90). The dosage was gradually escalated over 9 weeks and then maintained until Week 40, at which time active treatment was withdrawn over 3 days. After 2 weeks without active treatment (Week 42), a final assessment of PD severity was obtained. OUTCOME MEASURES The prespecified primary clinical outcome was the change in the total Unified Parkinson's Disease Rating Scale (UPDRS) between baseline and Week 42, comparing the four treatment groups. The primary neuroimaging component of the study in a subgroup of 142 subjects was the percent change in striatal (123)iodine 2-beta-carboxymethoxy-3-beta-(4-iodophe nyl)tropane (beta-CIT) uptake between baseline and Week 40 visits. The neuroimaging substudy utilized single photon emission computed tomography (SPECT) of the dopamine transporter. RESULTS All dosages of levodopa exerted clinical benefit compared to placebo on the UPDRS scores throughout the study, including 2 weeks after discontinuing levodopa. The UPDRS scores at Week 42 failed to reach the level encountered in the placebo group (change of 7.8+/-9.0, 1.9+/-6.0, 1.9+/-6.9, and -1.4+/-7.8, for placebo, 150 mg/day, 300 mg/ day, and 600 mg/day, respectively, p<0.0001). Nausea (p=0.001) and dyskinesias (p=0.0001) were more common in the levodopa groups, especially with the higher dosages. Freezing appeared around the same time, but was more common in the placebo (14 %) and 150 mg/day group (10 %). The percent decline of beta-CIT uptake in the striatum was significantly more pronounced in the levodopa groups than the placebo group (-7.2%, -4%, -6%, and -1.4% in 600 mg/day, 300 mg/day, 150 mg/day, and placebo, respectively; p=0.035). CONCLUSIONS The clinical outcomes not only indicate that levodopa is effective in a dose-dependent manner in overcoming the signs and symptoms of PD, they also support the concept that the drug does not hasten the disease progression, but rather may slow down the rate of the disease. The clinical study failed to demonstrate any evidence of levodopa worsening early PD. However, the beta-CIT SPECT substudy indicates the opposite effect, namely that levodopa causes a more rapid decline in the integrity of the dopamine transporter located in the nigrostriatal nerve terminals in the striatum. These contradictory findings warrant further investigation into the effect of levodopa on PD. OTHER OBSERVATIONS: The ELLDOPA study was the first levodopa dose-response study ever conducted. It showed that dose is a factor in the cause of producing motor complications of dyskinesias and wearing-off, and that these can develop as early as 5 to 6 months. On the other hand, freezing of gait could be delayed or its occurrence reduced by high dosage levodopa, compared to placebo or low-dose levodopa. Withdrawal of levodopa over a 3-day step-down can be safely carried out without inducing the neuroleptic-like syndrome. The UPDRS was shown to be a reliable linear marker for disease progression. The ELLDOPA study also called into question the interpretation of beta-CIT SPECT in the presence of dopaminergic agents. Neuroimaging in ELLDOPA also showed that some people diagnosed with early PD do not have a dopaminergic deficit, calling into question how difficult the correct diagnosis may be in people with early symptoms of PD.
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Affiliation(s)
- Stanley Fahn
- Neurological Institute, Columbia University College of Physicians & Surgeons, 710 West 168th Street, New York, NY 10032, USA.
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Fahn S. Levodopa in the treatment of Parkinson's disease. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2006:1-15. [PMID: 17447410 DOI: 10.1007/978-3-211-33328-0_1] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Levodopa is the most efficacious drug to treat the symptoms of Parkinson's disease (PD) and is widely considered the "gold standard" by which to compare other therapies, including surgical therapy. Response to levodopa is one of the criteria for the clinical diagnosis of PD. A major limiting factor in levodopa therapy is the development of motor complications, namely dyskinesias and motor fluctuations. The ELLDOPA study was designed to determine if levodopa affected the progression of PD. This double-blind randomized study showed that the subjects treated with levodopa for 40 weeks had less severe parkinsonism than the placebo treated subjects even after a 2-week washout of medications, with the highest dose group showing the greatest benefit. Thus, levodopa may actually have neuroprotective value, but the result was not conclusive of slowing disease progression, because the same result could have arisen from a very long-lasting symptomatic benefit of levodopa.
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Affiliation(s)
- S Fahn
- Columbia University, New York, USA.
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19
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Yoshimi K, Ren YR, Seki T, Yamada M, Ooizumi H, Onodera M, Saito Y, Murayama S, Okano H, Mizuno Y, Mochizuki H. Possibility for neurogenesis in substantia nigra of parkinsonian brain. Ann Neurol 2005; 58:31-40. [PMID: 15912513 DOI: 10.1002/ana.20506] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Recent studies of enhanced hippocampal neurogenesis by antidepressants suggest enhancement of neurogenesis is a potentially effective therapy in neurodegenerative diseases. In this study, we evaluated nigral neurogenesis in animals and autopsy brains including patients with Parkinson's disease (PD). First, proliferating cells in substantia nigra were labeled with retroviral transduction of green fluorescent protein, which is an efficient method to label neuronal stem cells. Subsequent differentiation of labeled cells was followed; many transduced cells became microglia, but no differentiation into tyrosine hydroxylase-positive neurons was detected at 4 weeks after injection, in both intact rodents and those treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Second, polysialic acid (PSA)-like immunoreactivity, indicative of newly differentiated neurons, was detected in the substantia nigra of rodent, primate, and human midbrains. A large number of PSA-positive cells were detected in the substantia nigra pars reticulata of some patients with PD. In rats and a macaque monkey, the dopamine-depleted hemispheres showed more PSA staining than the intact side. A small number of tyrosine hydroxylase-positive cells were PSA-positive. Our results suggest enhanced neural reconstruction in PD, which may be important in the design of new therapies against the progression of PD.
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Affiliation(s)
- Kenji Yoshimi
- Research Institute for Diseases of Old Ages, Juntendo University, Bunkyo-ku, Tokyo, Japan
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Smeyne RJ, Jackson-Lewis V. The MPTP model of Parkinson's disease. ACTA ACUST UNITED AC 2005; 134:57-66. [PMID: 15790530 DOI: 10.1016/j.molbrainres.2004.09.017] [Citation(s) in RCA: 255] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Revised: 09/13/2004] [Accepted: 09/21/2004] [Indexed: 12/21/2022]
Abstract
The biochemical and cellular changes that occur following administration of 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) are remarkably similar to that seen in idiopathic Parkinson's disease (PD). In this review, we detail the molecular activities of this compound from peripheral intoxication through its various biotransformations. In addition, we detail the interplay that occurs between the different cellular compartments (neurons and glia) that eventually consort to kill substantia nigra pars compacta (SNpc) neurons.
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Affiliation(s)
- Richard Jay Smeyne
- Department of Developmental Neurobiology, Saint Jude Children's Research Hospital, Memphis, TN 39105, USA.
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Chalimoniuk M, Stepień A, Strosznajder JB. Pergolide Mesylate, a Dopaminergic Receptor Agonist, Applied With l-DOPA Enhances Serum Antioxidant Enzyme Activity in Parkinson Disease. Clin Neuropharmacol 2004; 27:223-9. [PMID: 15602103 DOI: 10.1097/01.wnf.0000145509.84389.ce] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The aim of this study was to compare patients with Parkinson disease (PD) patients treated with pergolide mesylate (PM), a dopaminergic receptor agonist, together with L-DOPA and those these treated with L-DOPA alone on the concentration of free radicals (FR), glutathione, and the activity of superoxide dismutase (SOD) and catalase in the serum. The study was carried out using 16 age-matched control subjects, 16 PD patients treated with L-DOPA at a dose of 1 to 1.5 g daily, and 16 PD patients treated with L-DOPA 1 to 1.5 g daily with PM 0.75 to 1.25 mg daily. The mean duration of treatment of PD was 6 years (range, 2-8 years) with l-DOPA, and 2 years with PM + L-DOPA or L-DOPA alone. Although there was no significant difference in lipid peroxidation products among the 3 groups, patients treated with L-DOPA showed high levels of FR as determined by dichlorofluorescein. Although catalase and SOD activities were elevated in both groups of PD patients, additional treatment with PM further enhanced catalase activity compared with those treated with l-DOPA alone. Interestingly, patients treated with PM + L-DOPA showed a significantly increased level of glutathione compared with those treated with L-DOPA alone. Collectively, these data suggest that PM + L-DOPA is a more efficient therapy in maintaining an antioxidative defense in PD patients compared with treatment with L-DOPA alone.
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Affiliation(s)
- Malgorzata Chalimoniuk
- Department of Cellular Signaling, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
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22
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Abstract
Parkinson's disease is the most common serious movement disorder in the world, affecting about 1% of adults older than 60 years. The disease is attributed to selective loss of neurons in the substantia nigra, and its cause is enigmatic in most individuals. Symptoms of Parkinson's disease respond in varying degrees to drugs, and surgery offers hope for patients no longer adequately controlled in this manner. The high prevalence of the disease, and important advances in its management, mean that generalists need to have a working knowledge of this disorder. This Seminar covers the basics, from terminology to aspects of diagnosis, treatment, and pathogenesis.
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Affiliation(s)
- Ali Samii
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA.
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Grace A. Forebrain dopamine systems--can they help us to understand psychosis? Eur Psychiatry 2003; 18 Suppl 2:27s-31s. [PMID: 23570193 DOI: 10.1016/s0924-9338(03)80002-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Under normal circumstances, emotional and affective signals within the brain are tempered by signals from higher brain centres, including the forebrain. These control systems ensure that responses to emotional and affective stimuli are appropriate for the environment within which they are generated. In patients with schizophrenia, these control systems are dysfunctional causing the patients to become oversensitive to such emotional stimuli and leading to the exaggerated reactions that are symptomatic of the disease [7,19].
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Affiliation(s)
- Anthony Grace
- Department of Neuroscience, 458 Crawford Hall, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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Blanchet PJ, Konitsiotis S, Mochizuki H, Pluta R, Emerich DF, Chase TN, Mouradian MM. Complications of a trophic xenotransplant approach in parkinsonian monkeys. Prog Neuropsychopharmacol Biol Psychiatry 2003; 27:607-12. [PMID: 12787846 DOI: 10.1016/s0278-5846(03)00048-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Various restorative cell transplantation strategies have been investigated to substitute for lost dopamine (DA) neurons or to enhance DA synthesis in Parkinson's disease. Intracerebral implantation of engineered cells encapsulated in a semipermeable polymer membrane constitutes one way to deliver bioactive substances unable to cross the blood-brain barrier while avoiding the need for long-term immunosuppression. Glial cell line-derived neurotrophic factor (GDNF) has shown trophic effects on DA neurons but effective and sustained delivery within the brain parenchyma remains problematic. The long-term efficacy and late complications of a xenotransplant approach utilizing GDNF-expressing encapsulated baby hamster kidney (BHK) cells were examined. Each of five MPTP-lesioned parkinsonian cynomolgus monkeys received five devices containing active or inert cells grafted bilaterally in the striatum in a two-stage procedure 9 months apart and animals were sacrificed 4 months later for analyses. No definite motor benefit was observed, DA levels were comparable between GDNF- and control cell-implanted striata, and tyrosine hydroxylase (TH) immunoreactivity in the substantia nigra showed no consistent recovery. Cell viability and GDNF synthesis in the explanted devices were negligible. The brain tissue surrounding all implants showed an intense immune reaction with prominent "foreign body" inflammatory infiltrates. Membrane biophysics, the cell type used, and the extended period of time the devices remained in situ may have contributed to the negative outcome and should be addressed in future investigations using this approach.
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Affiliation(s)
- Pierre J Blanchet
- Experimental Therapeutics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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