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Editorial A critical evaluation of the Braak staging scheme for Parkinson's disease. 2008
Burke RE, Dauer WT, Vonsattel JP. · Department of Neurology, Columbia University Medical Center, New York, NY, USA. · Ann Neurol. · Pubmed #19067353 No free full text.
Abstract: Braak and colleagues have proposed that, within the central nervous system, Parkinson's disease (PD) begins as a synucleinopathy in nondopaminergic structures of the lower brainstem or in the olfactory bulb. The brainstem synucleinopathy is postulated to progress rostrally to affect the substantia nigra and cause parkinsonism at a later stage of the disease. In the context of a diagnosis of PD, made from current clinical criteria, the pattern of lower brainstem involvement accompanying mesencephalic synucleinopathy is often observed. However, outside of that context, the patterns of synucleinopathy that Braak described are often not observed, particularly in dementia with Lewy bodies and when synucleinopathy occurs in the absence of neurological manifestations. The concept that lower brainstem synucleinopathy represents "early PD" rests on the supposition that it has a substantial likelihood of progressing within the human lifetime to involve the mesencephalon, and thereby cause the substantia nigra pathology and clinical parkinsonism that have heretofore defined the disease. However, the predictive validity of this concept is doubtful, based on numerous observations made in populations of aged individuals who, despite the absence of neurological signs, have brain synucleinopathy ranging up to Braak stages 4 to 6 at postmortem. Furthermore, there is no relation between Braak stage and the clinical severity of PD. We conclude that the relation between patterns of abnormal synuclein immunostaining in the human brain and the disease entity now recognized as PD remains to be determined.
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Review The scientific and clinical basis for the treatment of Parkinson disease (2009). 2009
Olanow CW, Stern MB, Sethi K. · Department of Neurology, Mount Sinai School of Medicine, 1 Gustave Levy Place, Annenberg 14-94, New York, NY 10029, USA. · Neurology. · Pubmed #19470958 No free full text.
Abstract: Parkinson disease (PD) is an age-related neurodegenerative disorder that affects as many as 1-2% of persons aged 60 years and older. With the aging of the population, the frequency of PD is expected to increase dramatically in the coming decades. Current therapy is largely based on a dopamine replacement strategy, primarily using the dopamine precursor levodopa. However, chronic treatment is associated with the development of motor complications, and the disease is inexorably progressive. Further, advancing disease is associated with the emergence of features such as freezing, falling, and dementia which are not adequately controlled with dopaminergic therapies. Indeed, it is now appreciated that these nondopaminergic features are common and the major source of disability for patients with advanced disease. Many different therapeutic agents and treatment strategies have been evaluated over the past several years to try and address these unmet medical needs, and many promising approaches are currently being tested in the laboratory and in the clinic. As a result, there are now many new therapies and strategic approaches available for the treatment of the different stages of PD, with which the treating physician must be familiar in order to provide patients with optimal care. This monograph provides an overview of the management of PD patients, with an emphasis on pathophysiology, and the results of recent clinical trials. It is intended to provide physicians with an understanding of the different treatment options that are available for managing the different stages of the disease and the scientific rationale of the different approaches.
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Review Deep brain stimulation--surgery for movement disorders and Parkinson's disease. 2009
Frost EA, Osborn I. · Department of Anesthesiology, the Mount Sinai Medical Center, 1 Gustave L. Levy Place, New York, NY, USA. · Int Anesthesiol Clin. · Pubmed #19359876 No free full text.
This publication has no abstract.
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Review Cognitive and limbic circuits that are affected by deep brain stimulation. 2009
Haber SN, Brucker JL. · Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, New York 14642, USA. · Front Biosci. · Pubmed #19273166 No free full text.
Abstract: Several lines of evidence indicate that the neural network that underlies the pathophysiology of obsessive-compulsive disorder and depression centers on the prefronto-basal ganglia system. Particularly involved are anterior cingulate cortex, the orbital prefrontal cortex, the ventral striatum, and parts of the thalamus. Additional integral parts of the network include, the amygdala, the midbrain dopamine cells and the serotonergic neurons. Collectively, these brain regions are involved in various aspects of reward-based learning and good decision-making skills. They are also associated with sadness and depression, pathological risk-taking, addictive behaviors, and obsessive-compulsive disorder. Two of the most successful deep brain stimulation targets for obsessive-compulsive disorder and depression are centered in white matter tracts. These targets were chosen for their central location and ability to capture specific ascending and descending connections, with a particular focus on fibers connecting the subgenual anterior cingulate and orbital cortex with the basal ganglia, thalamus, and amygdala. As more knowledge is obtained concerning the details of these connections, more precise targets may be possible.
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Review Protein homeostasis and aging: taking care of proteins from the cradle to the grave. 2009
Morimoto RI, Cuervo AM. · Department of Developmental and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, Bronx, NY 10461, USA. · J Gerontol A Biol Sci Med Sci. · Pubmed #19228787 No free full text.
Abstract: All cells count on precise mechanisms that regulate protein homeostasis to maintain a stable and functional proteome. Alterations in these fine-tuned mechanisms underlie the pathogenesis of severe human diseases including, among others, common neurodegenerative disorders such as Alzheimer's or Parkinson's disease. A progressive deterioration in the ability of cells to preserve the stability of their proteome occurs with age, even in the absence of disease, and it likely contributes to different aspects of "normal" aging. A group of experts in different aspects of the biology of aging met recently to discuss the implications of altered protein homeostasis in aging, the current gaps in our understanding of the mechanisms responsible for proteome maintenance, and future opportunities for discovery in this area. We summarize here some of the key topics and main outcomes of the discussions.
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Review Can we achieve neuroprotection with currently available anti-parkinsonian interventions? 2009
Olanow CW. · Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA. · Neurology. · Pubmed #19221316 No free full text.
Abstract: A disease-modifying therapy is the most important unmet medical need in the treatment of Parkinson disease (PD). Laboratory studies have identified many promising candidate agents, but none has been proven to be neuroprotective in PD. A major limitation has been the development of an endpoint that accurately reflects the underlying disease state. This dramatically limits the potential for a new drug being approved as a disease-modifying agent in PD. For the present, the best opportunity to provide patients with PD with a disease-modifying effect is with agents that have been approved for their symptomatic effects. This article reviews currently available drugs for PD and considers the evidence that they might have neuroprotective effects in PD.
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Review Cell death pathways in Parkinson's disease: proximal triggers, distal effectors, and final steps. 2009
Levy OA, Malagelada C, Greene LA. · Department of Neurology, Columbia University School of Medicine, New York, NY, USA. · Apoptosis. · Pubmed #19165601 No free full text.
Abstract: Parkinson's disease (PD) is a common neurodegenerative disorder. Neuronal cell death in PD is still poorly understood, despite a wealth of potential pathogenic mechanisms and pathways. Defects in several cellular systems have been implicated as early triggers that start cells down the road toward neuronal death. These include abnormal protein accumulation, particularly of alpha-synuclein; altered protein degradation via multiple pathways; mitochondrial dysfunction; oxidative stress; neuroinflammation; and dysregulated kinase signaling. As dysfunction in these systems mounts, pathways that are more explicitly involved in cell death become recruited. These include JNK signaling, p53 activation, cell cycle re-activation, and signaling through bcl-2 family proteins. Eventually, neurons become overwhelmed and degenerate; however, even the mechanism of final cell death in PD is still unsettled. In this review, we will discuss cell death triggers and effectors that are relevant to PD, highlighting important unresolved issues and implications for the development of neuroprotective therapies.
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Review Parkinson's disease and the orthopaedic patient. 2009
Zuckerman LM. · Department of orthopaedic Surgery and Rehabilitation Medicine, Suny Downstate Medical Center, Brooklyn, NY, USA. · J Am Acad Orthop Surg. · Pubmed #19136427 No free full text.
Abstract: Parkinson's disease is a progressive neurologic disorder that affects the musculoskeletal system in multiple ways. As medication and surgical management of this disorder have improved, the life spans and quality of life of patients affected by it also have improved. With age, the risk of fracture, osteoarthritis, and osteopenia increase in patients with Parkinson's disease compared with the general population. The symptoms of Parkinson's disease predispose patients to gait abnormalities and loss of bone mass, which commonly result in falls and fracture. Although preventive measures such as medication, lifestyle changes, and vitamin replacement may help, surgical intervention is often indicated. Surgical treatment and postoperative management of both elective and emergent surgery are complicated and controversial.
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Review Why have we failed to achieve neuroprotection in Parkinson's disease? 2008
Olanow CW, Kieburtz K, Schapira AH. · Department of Neurology, Mount Sinai School of Medicine, New York, USA. · Ann Neurol. · Pubmed #19127580 No free full text.
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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Review How do you treat motor complications in Parkinson's disease: Medicine, surgery, or both? 2008
Fahn S. · Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY, USA. · Ann Neurol. · Pubmed #19127577 No free full text.
Abstract: The motor complications associated with levodopa therapy, namely, fluctuations in motor response and dyskinesias, occur in the majority of Parkinson's disease patients. These complications can impair a patient's quality of life and even cause pronounced disability. "Off" states that result in freezing of gait and falling are disabling for many patients. Dyskinesias most commonly occur at peak dose and typically alternate with the wearing-off state. Once these problems appear, they usually persist, and the physician needs to make continual adjustments in medications to minimize these problems. Medical treatments should be attempted before treatments such as deep brain stimulation are considered because of the potential adverse effects that are associated with surgery. The timing of surgery, however, is also important because younger patients and less advanced patients tend to have a better outcome. There is thus a need for experienced and knowledgeable physicians and surgeons who are able to handle these motor complications. This review discusses available medications and surgical approaches, and their outcomes.
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Review Multinuclear magnetic resonance spectroscopy for in vivo assessment of mitochondrial dysfunction in Parkinson's disease. 2008
Henchcliffe C, Shungu DC, Mao X, Huang C, Nirenberg MJ, Jenkins BG, Beal MF. · Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10021, USA. · Ann N Y Acad Sci. · Pubmed #19076443 No free full text.
Abstract: Parkinson's disease (PD) is a common and often devastating neurodegenerative disease affecting up to one million individuals in the United States alone. Multiple lines of evidence support mitochondrial dysfunction as a primary or secondary event in PD pathogenesis; a better understanding, therefore, of how mitochondrial function is altered in vivo in brain tissue in PD is a critical step toward developing potential PD biomarkers. In vivo study of mitochondrial metabolism in human subjects has previously been technically challenging. However, proton and phosphorus magnetic resonance spectroscopy ((1)H and (31)P MRS) are powerful noninvasive techniques that allow evaluation in vivo of lactate, a marker of anaerobic glycolysis, and high energy phosphates, such as adenosine triphosphate and phosphocreatine, directly reflecting mitochondrial function. This article reviews previous (1)H and (31)P MRS studies in PD, which demonstrate metabolic abnormalities consistent with mitochondrial dysfunction, and then presents recent (1)H MRS data revealing abnormally elevated lactate levels in PD subjects.
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Review Oxidative stress in Parkinson's disease: a mechanism of pathogenic and therapeutic significance. 2008
Zhou C, Huang Y, Przedborski S. · Department of Neurology, Columbia University, New York, NY 10032, USA. · Ann N Y Acad Sci. · Pubmed #19076434 No free full text.
Abstract: Parkinson's disease (PD) is a common adult-onset neurodegenerative disorder. Typically PD is a sporadic neurological disorder, and over time affected patients see their disability growing and their quality of life declining. Oxidative stress has been hypothesized to be linked to both the initiation and the progression of PD. Preclinical findings from both in vitro and in vivo experimental models of PD suggest that the neurodegenerative process starts with otherwise healthy neurons being hit by some etiological factors, which sets into motion a cascade of deleterious events. In these models initial molecular alterations in degenerating dopaminergic neurons include increased formation of reactive oxygen species, presumably originating from both inside and outside the mitochondria. In the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD, time-course experiments suggest that oxidative stress is an early event that may directly kill some of the dopaminergic neurons. In this model it seems that oxidative stress may play a greater role in the demise of dopaminergic neurons indirectly by activating intracellular, cell death-related, molecular pathways. As the neurodegenerative process evolves in the MPTP mouse model, indices of neuroinflammation develop, such as microglial activation. The latter increases the level of oxidative stress to which the neighboring compromised neurons are subjected to, thereby promoting their demise. However, these experimental studies have also shown that oxidative stress is not the sole deleterious factor implicated in the death of dopaminergic neurons. Should a similar multifactorial cascade underlie dopaminergic neuron degeneration in PD, then the optimal therapy for this disease may have to rely on a cocktail of agents, each targeting a different critical component of this hypothesized pathogenic cascade. If correct, this may be a reason why neuroprotective trials using a single agent, such as an antioxidant, have thus far generated disappointing results.
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Review Ubiquitin-dependent and -independent mitochondrial protein quality controls: implications in ageing and neurodegenerative diseases. 2008
Germain D. · Mount Sinai School of Medicine, Division of Hematology/Oncology Box 1079, One Gustave L. Levy Place, New York, NY 11029, USA. · Mol Microbiol. · Pubmed #19019155 No free full text.
Abstract: The ubiquitin-independent protein quality control of matrix proteins of the mitochondrion is well characterized and until recently the mitochondrion was considered a 'ubiquitination-free' organelle. However, a number of studies now indicate multiple roles of the ubiquitin-proteasome pathway in the regulation and maintenance of mitochondrial integrity. Of particular interest to this review is the finding of a mitochondrial ubiquitin-dependent protein quality control and that this pathway may share similarity to the endoplasmic reticulum-associated degradation (ERAD) pathway that acts to eliminate misfolded proteins from the lumen of the endoplasmic reticulum. The potential cross-talk between the ubiquitin-dependent and -independent protein quality controls and their implications in ageing and neurodegenerative diseases, notably in Parkinson's disease, are discussed.
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Review Mitochondrial biology and oxidative stress in Parkinson disease pathogenesis. 2008
Henchcliffe C, Beal MF. · Department of Neurology and Neuroscience at the Weill Medical College of Cornell University, New York, NY 10021, USA. · Nat Clin Pract Neurol. · Pubmed #18978800 No free full text.
Abstract: Parkinson disease (PD) is associated with progressive loss of dopaminergic neurons in the substantia nigra, as well as with more-widespread neuronal changes that cause complex and variable motor and nonmotor symptoms. Recent rapid advances in PD genetics have revealed a prominent role for mitochondrial dysfunction in the pathogenesis of the disease, and the products of several PD-associated genes, including SNCA, Parkin, PINK1, DJ-1, LRRK2 and HTR2A, show a degree of localization to the mitochondria under certain conditions. Impaired mitochondrial function is likely to increase oxidative stress and might render cells more vulnerable to this and other related processes, including excitotoxicity. The mitochondria, therefore, represent a highly promising target for the development of disease biomarkers by use of genetic, biochemical and bioimaging approaches. Novel therapeutic interventions that modify mitochondrial function are currently under development, and a large phase III clinical trial is underway to examine whether high-dose oral coenzyme Q10 will slow disease progression. In this Review, we examine evidence for the roles of mitochondrial dysfunction and increased oxidative stress in the neuronal loss that leads to PD and discuss how this knowledge might further improve patient management and aid in the development of 'mitochondrial therapy' for PD.
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Review Therapeutic strategies to prevent motor complications in Parkinson's disease. 2008
Kieburtz K. · University of Rochester Medical Center, 1351 Mt. Hope Ave., Ste. 223, Rochester, NY 14620, USA. · J Neurol. · Pubmed #18821085 No free full text.
Abstract: Dopaminergic treatment of Parkinson's disease (PD) leads to significant improvement in Parkinsonian features; however, the treatment response is hampered by the appearance of motor complications, including dyskinesias and motor fluctuations. These motor complications have a significant negative impact on quality-of-life. Therapeutic strategies using different types and timing of dopaminergic therapy may influence the emergence of motor complications. While sustained release preparations of levodopa have not shown benefit over immediate release preparations, the early combination of a dopamine agonist with levodopa appears to reduce the onset of motor fluctuations. An even larger body of evidence has found that initiating treatment with a dopamine receptor agonist (as compared to immediate release levodopa) is associated with a reduction in motor fluctuations, particularly dyskinesias. These data have led to evidence-based medicine evaluations indicating that the use of dopamine agonists is efficacious and clinically useful for the prevention of motor complications.
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Review Parkinson disease: primacy of age as a risk factor for mitochondrial dysfunction. 2008
Vanitallie TB. · Division of Endocrinology, Diabetes, and Nutrition, Department of Medicine, St Luke's-Roosevelt Hospital Center, New York, NY 10025, USA. · Metabolism. · Pubmed #18803967 No free full text.
Abstract: In 1983, it was reported that certain drug users with a history of exposure to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, a contaminant of an illicitly produced meperidine analogue, developed an irreversible syndrome resembling idiopathic Parkinson disease (PD). Soon thereafter, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine's active metabolite, 1-methyl-4-phenylpyridine, was shown to be a complex I inhibitor. Activity of complex I (the point of entry for most electrons that traverse the mitochondrial electron transport chain) has been found to be impaired in the substantia nigra pars compacta and also in other brain tissues in PD patients. In 2006, high temporal and spatial resolution phosphorous functional magnetic resonance spectroscopy was used to demonstrate that, in 20 PD patients, mitochondrial dysfunction extended to the visual cortex. Epidemiologic studies have implicated a number of apparently disparate exogenous factors in the causation of PD. For example, exposure to certain pesticides and herbicides (many known to inhibit electron transport chain activity) increases PD risk. Parkinson disease risk can be doubled, tripled, or more in individuals with repeated head injuries. Over time, PD risk is almost doubled in men and women with prior type 2 diabetes mellitus. Nevertheless, despite evidence that certain exogenous and/or developmental factors play a role in causation of PD, their potential effect on PD incidence is greatly overshadowed by that of advancing age. In 1 prospective study, PD incidence rate in subjects at least 85 years old was about 14 times that observed in subjects aged 56 to 65 years. The dramatic effect of aging on PD risk may be explained in part by the fact that mitochondrial DNA deletions are abundant and cause functional impairment in aged human substantia nigra pars compacta neurons. High levels of these mutations are associated with electron transport chain deficiency, a situation that favors increased oxidative damage, Lewy body formation, and apoptotic cell death. Systematic study of the effects of putative risk factors in animal models of parkinsonism may be expected to improve our understanding of PD's complex pathogenesis.
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Review The history of dopamine and levodopa in the treatment of Parkinson's disease. 2008
Fahn S. · Columbia University, New York, USA. · Mov Disord. · Pubmed #18781671 No free full text.
Abstract: The discoveries of dopamine as a neurotransmitter in the brain, its depletion in patients with Parkinson disease, and its replacement with levodopa therapy were major revolutionary events in the rise to effective therapy for patients with this disorder. This review describes these events and the persons who carried out these accomplishments. Their impact went beyond a single clinical entity of parkinsonism, for it opened up the beginning of a much better understanding of the role of dopamine in other neurologic movement disorders and also in many psychiatric diseases.
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Review Levodopa/dopamine replacement strategies in Parkinson's disease--future directions. 2008
Olanow CW. · Department of Neurology, Mount Sinai School of Medicine, New York, New York, USA. · Mov Disord. · Pubmed #18781663 No free full text.
Abstract: After 40 years, levodopa remains the most effective therapy for the treatment of PD. However, long-term therapy is complicated by motor fluctuations and dyskinesia that can represent a source of significant disability for some patients. Other medical therapies that are currently available for the treatment of PD primarily represent an attempt to prevent or treat motor complications. Surgical therapies improve motor complications in appropriate candidates, but do not provide antiparkinsonian benefits that are superior to levodopa, and are themselves associated with potentially serious side effects. Increasing information suggests that levodopa-induced motor complications relate to pulsatile, nonphysiologic dopamine replacement. A therapeutic strategy that could deliver levodopa/dopamine to the brain in a more continuous and physiologic manner might be expected to provide all of the benefits of standard levodopa with reduced motor complications. Such a levodopa formulation might replace all current dopaminergic antiparkinsonian medications and avoid the need for surgery in most PD patients. However, problems of continuous dopaminergic stimulation must be addressed and avoided, and the issue of nondopaminergic features remains to be addressed.
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Review Neuroprotection in Parkinson's disease: myth or reality? 2008
Voss T, Ravina B. · Department of Neurology, University of Rochester School of Medicine and Dentistry, Movement and Inherited Neurological Disorders Unit, Rochester, NY 14620, USA. · Curr Neurol Neurosci Rep. · Pubmed #18590614 No free full text.
Abstract: Parkinson's disease (PD) is a chronic, progressive, neurodegenerative disorder with no cure. Therapies that delay or halt disease progression are urgently needed, but finding such therapies has been difficult. In this article, we review historical and recent clinical trial work in the field of neuroprotection. Several issues have arisen during the search for disease-modifying therapies, including challenges in selecting appropriate therapeutic targets, assessing potential therapies, and selecting the proper patient population to study. Advances in the understanding of PD pathogenesis are presented as they relate to selecting potential therapeutic targets, and issues with preclinical testing are described. We review recent innovations in clinical trial design, including futility studies and delayed-start designs that promise to make clinical testing more efficient. It is hoped that ongoing work in this field will lead to treatments that delay the progression of PD.
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Review PPAR: a therapeutic target in Parkinson's disease. 2008
Chaturvedi RK, Beal MF. · Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York, USA. · J Neurochem. · Pubmed #18384649 No free full text.
Abstract: Parkinson's disease (PD) is a progressive and chronic neurodegenerative disorder, characterized by progressive loss of dopaminergic neurons in substantia nigra. The etiology and pathogenesis of PD is still elusive, however, a large body of evidence suggests a prominent role of oxidative stress, inflammation, apoptosis, mitochondrial dysfunction and proteosomal dysfunction in the pathogenesis of PD. Due to multifactorial nature of the disease, currently available drug therapy cannot halt / slow down the disease progression, and only provides symptomatic relief. Peroxisome proliferator-activated receptor (PPAR), a member of nuclear receptor superfamily, regulates development, tissue differentiation, inflammation, mitochondrial function, wound healing, lipid metabolism and glucose metabolism. Recently, several PPAR agonists were shown to exert neuroprotective activity against oxidative damage, inflammation and apoptosis in several neurodegenerative disorders including Alzheimer's, Parkinson's, Huntington's, amyotrophic lateral sclerosis and multiple sclerosis. Similarly, regular intake of PPAR activating non-steroidal anti-inflammatory drugs such as indomethacin and ibuprofen was associated with reduced incidence and progression of neurodegenerative disorders in several epidemiological studies. In this article, we review studies relating to the neuroprotective effect of PPAR agonists in in vitro and in vivo models of PD. Similarly, the pharmacological mechanism in neuroprotective actions of PPAR agonists is also reviewed. In conclusion, PPAR agonists exert neuroprotective actions by regulating the expression of a set of genes involved in cell survival processes, and could be a therapeutic target in debilitating neurodegenerative illnesses such as PD.
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Review Desire, disease, and the origins of the dopaminergic system. free! 2008
Sillitoe RV, Vogel MW. · Developmental Biology Program, Sloan-Kettering Institute, 1275 York Avenue, New York, NY 10021, USA. · Schizophr Bull. · Pubmed #18283047 links to free full text
Abstract: The dopaminergic neurons in the midbrain region of the central nervous system project an extensive network of connections throughout the forebrain, including the neocortex. The midbrain-forebrain dopaminergic circuits are thought to regulate a diverse set of behaviors, from the control of movement to modulation of cognition and desire--because they relate to mood, attention, reward, and addiction. Defects in these pathways, including neurodegeneration, are implicated in a variety of psychiatric and neurological diseases, such as schizophrenia, attention-deficit/hyperactivity disorder, drug addiction, and Parkinson disease. Based on the importance of the midbrain dopaminergic neurons to normal and pathological brain function, there is considerable interest in the molecular mechanisms that regulate their development. The goal of this short review is to outline new methods and recent advances in identifying the molecular networks that regulate midbrain dopaminergic neuron differentiation and fate. Midbrain dopaminergic neurons are descended from progenitor cells located near the ventral midline of the neural tube floor plate around the cephalic flexure. It is now clear that their initial formation is dependent on interactions between the signaling molecules Sonic hedgehog, WINGLESS 1, and FIBROBLAST growth factor 8, but there is still an extensive wider network of molecular interactions that must be resolved before the complete picture of dopaminergic neuron development can be described.
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Review The pathogenesis of cell death in Parkinson's disease--2007. 2007
Olanow CW. · Department of Neurology, Mount Sinai School of Medicine, New York, New York 10029, USA. · Mov Disord. · Pubmed #18175394 No free full text.
Abstract: A number of factors have been implicated in the pathogenesis of cell death in Parkinson's disease (PD). These include oxidative stress, mitochondrial dysfunction, inflammation, excitotoxicity, and apoptosis. While the precise pathogenic mechanism leading to neurodegeneration in PD is not known, there is considerable evidence suggesting that cell death occurs by way of a signal-mediated apoptotic process. PD is also characterized by intracellular proteinaceous inclusions or Lewy bodies. Proteolytic stress arises as a consequence of the excessive production of misfolded proteins, which exceed the capacity of the ubiquitin-proteasome system to degrade them. Recent genetic and laboratory studies support the possible relevance of proteolytic stress to both familial and sporadic forms of PD. Postmortem studies have shown that in the SNc of sporadic PD patients there are reduced levels of the alpha subunit of the 20S proteasome and reduced proteolytic enzyme activities. A determination as to the precise cause of cell death in PD, and the identification of specific targets for the development of drugs that might modify disease progression is one of the most critical goals in PD research. It is anticipated that over the next few years there will be a flurry of scientific activity examining the mechanism of cell death and putative neuroprotective interventions.
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Review Evolving applications of light therapy. 2007
Terman M. · Department of Psychiatry, Columbia University, New York State Psychiatric Institute, 1051 Riverside Drive, Unit 50, New York, NY 10032, USA. · Sleep Med Rev. · Pubmed #17964200 No free full text.
Abstract: The psychiatric intervention, light therapy, grew from an intensive 25-year research focus on seasonal affective disorder (SAD). Dosing and timing strategies have been honed to optimize the antidepressant effect, and efficacy relative to placebo has provided the evidence base for widespread implementation. A persistent question has been whether the model system for SAD has wider utility for psychiatric disturbance, even beyond depression. The circadian phase-shifting capacity of timed light exposure is universal, and chronobiological factors are at play across the disease spectrum. Recent promising initiatives extend to light treatment for nonseasonal major depressive disorder and bipolar depression, including drug- and electroconvulsive therapy-resistant cases. With light therapy, patients with antepartum depression may find an alternative to medication during pregnancy. Cognitive improvement under light therapy has been noted in adult attention deficit hyperactivity disorder. Motor function in Parkinson's disease has improved in parallel with the antidepressant effect of light therapy. The rest-activity disturbance of elderly dementia has been partially allayed under light therapy. In a new initiative, three major chronotherapeutic inventions-light therapy, sleep deprivation (wake therapy) and sleep time displacement (sleep phase advance therapy) are being combined to snap hospitalized patients out of deep depression and maintain long-term improvement.
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Review Zydis selegiline in the management of Parkinson's disease. 2007
Poston KL, Waters C. · Columbia University Medical Center, Department of Neurology, Division of Movement Disorders, 710 W. 168th Street, New York, NY 10032, USA. · Expert Opin Pharmacother. · Pubmed #17931095 No free full text.
Abstract: Selegiline, a selective monoamine oxidase-B inhibitor, has been used for decades in the treatment of Parkinson's disease. The recent development of an orally disintegrating dosage form using Zydis technology allows pregastric drug absorption and, thus, greatly improving the pharmacodynamic and pharmacokinetic drug profiles. This new formulation provides higher drug bioavailability and a substantially reduced concentration of active metabolites. As an adjunct to levodopa, Zydis selegiline is shown to be a safe and effective therapy in patients with motor fluctuations and wearing off. This review outlines the advantages of a Zydis formulation in Parkinson's disease and the evidence supporting the use of Zydis selegiline for motor fluctuations.
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Review Role of HMG-CoA reductase inhibitors in neurological disorders : progress to date. 2007
Reiss AB, Wirkowski E. · SUNY Stony Brook School of Medicine, Vascular Biology Institute, Winthrop-University Hospital, Mineola, NY 11501, USA. · Drugs. · Pubmed #17927279 No free full text.
Abstract: Inhibitors of HMG-CoA reductase (statins) are cholesterol-lowering agents that dramatically reduce morbidity and mortality in patients with established cardiovascular disease. In addition, they exhibit pleiotropic effects that operate independently of lipid modification. Statin administration results in greater nitric oxide bioavailability, improved endothelial function, enhanced cerebral blood flow, immune modulation with anti-inflammatory action, decreased platelet aggregation and antioxidant activity. Some or all of these effects may improve outcome or ameliorate symptoms in neurological disorders. This article examines the potential role of statins in treating stroke, Alzheimer's disease, multiple sclerosis and Parkinson's disease. Studies are ongoing in this controversial area, but there are no firm conclusions. The appropriateness of initiating statin therapy for neurological disorders is not established at this time. The exception is stroke, in which recurrence is significantly reduced by statin therapy.
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