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Raheel K, See QR, Munday V, Fakhroo B, Ivanenko O, Salvatelli ML, Mutti C, Goadsby PJ, Delogu A, Naismith SL, Holland P, Parrino L, Chaudhuri KR, Rosenzweig I. Orexin and Sleep Disturbances in Alpha-Synucleinopathies: a Systematic Review. Curr Neurol Neurosci Rep 2024; 24:389-412. [PMID: 39031323 PMCID: PMC11349833 DOI: 10.1007/s11910-024-01359-6] [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] [Accepted: 07/02/2024] [Indexed: 07/22/2024]
Abstract
PURPOSE OF REVIEW Sleep disturbances are amongst most frequent non-motor symptoms of Parkinson's Disease (PD), and they are similarly frequently reported in other alpha-syncleinopathies, such as Dementia with Lewy Bodies (DLB) and Multiple System Atrophy (MSA). More recently, the orexin system has been implicated in control of arousal based on salient environmental set points, and its dysregulation in sleep issues in alpha-synucleinopathies suggested by the findings from the translational animal models. However, its role in the patients with alpha-synucleinopathies remains unclear. We thus set to systematically review, and to critically assess, contemporary evidence on the association of the orexinergic system and sleep disturbances in alpha-synucleinopathies. In this systematic review, studies investigating orexin and sleep in alpha-synucleinopathies (Rapid Eye Movement (REM) Behaviour Disorder (RBD), Parkinson's Disease (PD), Dementia with Lewy Bodies (DLB), Multiple System Atrophy (MSA)) were identified using electronic database searches of PubMed, Web of Science and PsychINFO using MeSH terms, keywords, and title words such as "Alpha-synucleinopathies" AND "Orexin" AND "Sleep Disturbances". RECENT FINDINGS 17 studies were included in this systemic review, of which 2 studies on RBD, 10 on PD, 4 on DLB, and 1 on MSA patients. Taken together, RBD and PD studies suggest a potential adaptive increase in orexin levels in early stages of the neurodegenerative process, with reduced levels more often reported for later, more advanced stages of illness. To date, no differences in orexin levels were demonstrated between MSA patients and healthy controls. There is a dearth of studies on the role of orexin levels in alpha-synucleinopathies. Moreover, significant methodologic limitations in the current body of work, including use of non-standardised research protocols and lack of prospective, multi-centre studies, disallow for any finite conclusion in regards to underlying pathomechanisms. Nonetheless, a picture of a complex, multifaceted relationship between the dysregulation of the orexinergic pathway and sleep disturbances in alpha-synucleinopathies is emerging. Hence, future studies disentangling orexinergic pathomechanisms of alpha-syncleinopathies are urgently needed to obtain a more comprehensive account of the role of orexinergic pathway in alpha-synucleinopathies. Pharmacological manipulations of orexins may have multiple therapeutic applications in treatment strategies, disease diagnosis, and might be effective for treating both motor and non-motor symptoms.
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Affiliation(s)
- Kausar Raheel
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Qi Rui See
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Veronica Munday
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Basma Fakhroo
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Olga Ivanenko
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Marcello Luigi Salvatelli
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, De Crespigny Park, London, SE5 8AF, UK
- Sleep Disorders Center, Department of General and Specialized Medicine, University Hospital of Parma, 43125, Parma, Italy
| | - Carlotta Mutti
- Sleep Disorders Center, Department of General and Specialized Medicine, University Hospital of Parma, 43125, Parma, Italy
| | - Peter J Goadsby
- NIHR-Wellcome Trust King's Clinical Research Facility, King's College London, London, WC2R 2LS, UK
| | - Alessio Delogu
- Basic and Clinical Neuroscience, IoPPN, King's College London, London, WC2R 2LS, UK
| | - Sharon L Naismith
- Healthy Brain Ageing Program, School of Psychology; Brain and Mind Centre, The University of Sydney, & Charles Perkins Centre, Camperdown, Sydney, Australia
| | - Phil Holland
- Basic and Clinical Neuroscience, IoPPN, King's College London, London, WC2R 2LS, UK
| | - Liborio Parrino
- Sleep Disorders Center, Department of General and Specialized Medicine, University Hospital of Parma, 43125, Parma, Italy
- Department of Medicine and Surgery, Neurology Unit, University of Parma, 43125, Parma, Italy
| | - K Ray Chaudhuri
- Movement Disorders Unit, King's College Hospital and Department of Clinical and Basic Neurosciences, Institute of Psychiatry, Psychology & Neuroscience and Parkinson Foundation Centre of Excellence, King's College London, London, UK
| | - Ivana Rosenzweig
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, De Crespigny Park, London, SE5 8AF, UK.
- Sleep Disorders Centre, Guy's and St Thomas' NHS Foundation Trust, London, UK.
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Suresh V, Bardhan M, Ghosh S, Chandani Y, Satapathy P, Roy P, Shamim MA, Gandhi AP, Sandeep M, Rustagi S, Sah R, Padhi BK. Exploring the role of Orexin-A neuropeptide in Parkinson's disease: A systematic review and meta-analysis. Clin Neurol Neurosurg 2024; 242:108320. [PMID: 38781804 DOI: 10.1016/j.clineuro.2024.108320] [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: 08/14/2023] [Revised: 02/18/2024] [Accepted: 03/23/2024] [Indexed: 05/25/2024]
Abstract
BACKGROUND Parkinson's disease (PD) is a progressive neurological condition that affects movement and coordination. Orexin-A (OXA) is an excitatory neuropeptide that is found throughout the central nervous system. There is growing interest in investigating the potential diagnostic and therapeutic utility of OXA in PD. To date, studies have reported a wide range of OXA concentrations in patients with PD. In this review, we discuss the current understanding of the dysregulation of OXA in PD and analyze its levels in the CSF. METHODS We searched six databases (PubMed, Scopus, Web of Science, EMBASE, ProQuest, and EBSCOHost) and preprint servers using a predetermined search strategy through 4th March 4, 2023. The search keywords included "Parkinson's disease", "Orexin-A", "Hypocretin-1", "cerebrospinal fluid", and "CSF". Studies that reported OXA/Hypocretin-1 levels in the CSF of patients with PD were included. Two researchers independently reviewed the records and extracted data. FINDINGS Eighteen studies involving 244 patients were analyzed. CSF Orexin-A concentrations were lower in patients with Parkinson's disease than in controls, with a mean difference of -59.21 (95 % CI: -89.10 to -29.32). The mean OXA levels were 281.52 (95 % CI: 226.65-336.40). CONCLUSION Our analysis reveals lower concentrations of orexin-A in the cerebrospinal fluid of Parkinson's disease patients compared to controls, but within the normal range. These findings suggest a potential, but not significant, disruption in the orexinergic system associated with the disease.
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Affiliation(s)
- Vinay Suresh
- King George's Medical University, Lucknow 226003, India; Global Center for Evidence Synthesis, Chandigarh, 160036 India
| | - Mainak Bardhan
- Department of Neuro oncology,Miami Cancer Institute, Baptist Health South Florida,USA.
| | - Shankhaneel Ghosh
- Institute of Medical Sciences and SUM Hospital, Siksha 'O' Anusandhan, Bhubaneswar, India
| | - Yash Chandani
- King George's Medical University, Lucknow 226003, India
| | | | - Priyanka Roy
- Deputy Chief Inspector of Factories/ Deputy Director (Medical) and Certifying Surgeon, Directorate of Factories, Department of Labour, Government of West Bengal, India
| | - Muhammad Aaqib Shamim
- Department of Pharmacology, All India Institute of Medical Sciences, Jodhpur 342008, India
| | - Aravind P Gandhi
- Global Center for Evidence Synthesis, Chandigarh, 160036 India; Assistant Professor, Department of Community Medicine, ESIC Medical College & Hospital, Sanath Nagar, Hyderabad, India
| | - Mokanpally Sandeep
- Global Center for Evidence Synthesis, Chandigarh, 160036 India; School of Medical Sciences, University of Hyderabad, Telangana 500046, India
| | - Sarvesh Rustagi
- School of Applied and Life Sciences, Uttaranchal University, Dehradun, Uttarakhand, India
| | - Ranjit Sah
- Tribhuvan University Teaching Hospital, Kathmandu 46000, Nepal; Department of Public Health Dentistry, Dr. D.Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pune, Maharashtra 411018, India; Department of Clinical Microbiology, DY Patil Medical College, Hospital and Research Centre, DY Patil Vidyapeeth, Pune, Maharashtra 411000, India
| | - Bijaya K Padhi
- Department of Community Medicine and School of Public Health, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India.
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Braun A, Manavis J, Yamanaka A, Ootsuka Y, Blumbergs P, Bobrovskaya L. The role of orexin in Parkinson's disease. J Neurosci Res 2024; 102:e25322. [PMID: 38520160 DOI: 10.1002/jnr.25322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 02/28/2024] [Accepted: 03/09/2024] [Indexed: 03/25/2024]
Abstract
Emerging evidence has implicated the orexin system in non-motor pathogenesis of Parkinson's disease. It has also been suggested the orexin system is involved in the modulation of motor control, further implicating the orexin system in Parkinson's disease. Parkinson's disease is the second most common neurodegenerative disease with millions of people suffering worldwide with motor and non-motor symptoms, significantly affecting their quality of life. Treatments are based solely on symptomatic management and no cure currently exists. The orexin system has the potential to be a treatment target in Parkinson's disease, particularly in the non-motor stage. In this review, the most current evidence on the orexin system in Parkinson's disease and its potential role in motor and non-motor symptoms of the disease is summarized. This review begins with a brief overview of Parkinson's disease, animal models of the disease, and the orexin system. This leads into discussion of the possible roles of orexin neurons in Parkinson's disease and levels of orexin in the cerebral spinal fluid and plasma in Parkinson's disease and animal models of the disease. The role of orexin is then discussed in relation to symptoms of the disease including motor control, sleep, cognitive impairment, psychological behaviors, and the gastrointestinal system. The neuroprotective effects of orexin are also summarized in preclinical models of the disease.
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Affiliation(s)
- Alisha Braun
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Jim Manavis
- Discipline of Anatomy and Pathology, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | | | - Youichirou Ootsuka
- College of Medicine and Public Health, Flinders Medical and Health Research Institute, Flinders University, Adelaide, South Australia, Australia
| | - Peter Blumbergs
- Discipline of Anatomy and Pathology, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Larisa Bobrovskaya
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
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Tall P, Qamar MA, Rosenzweig I, Raeder V, Sauerbier A, Heidemarie Z, Falup-Pecurariu C, Chaudhuri KR. The Park Sleep subtype in Parkinson's disease: from concept to clinic. Expert Opin Pharmacother 2023; 24:1725-1736. [PMID: 37561080 DOI: 10.1080/14656566.2023.2242786] [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: 04/10/2023] [Accepted: 07/27/2023] [Indexed: 08/11/2023]
Abstract
INTRODUCTION The heterogeneity of Parkinson's disease (PD) is evident from descriptions of non-motor (NMS) subtypes and Park Sleep, originally identified by Sauerbier et al. 2016, is one such clinical subtype associated with the predominant clinical presentation of sleep dysfunctions including excessive daytime sleepiness (EDS), along with insomnia. AREAS COVERED A literature search was conducted using the PubMed, Medline, Embase, and Web of Science databases, accessed between 1 February 2023 and 28 March 2023. In this review, we describe the clinical subtype of Park Sleep and related 'tests' ranging from polysomnography to investigational neuromelanin MRI brain scans and some tissue-based biological markers. EXPERT OPINION Cholinergic, noradrenergic, and serotonergic systems are dominantly affected in PD. Park Sleep subtype is hypothesized to be associated primarily with serotonergic deficit, clinically manifesting as somnolence and narcoleptic events (sleep attacks), with or without rapid eye movement behavior disorder (RBD). In clinic, Park Sleep recognition may drive lifestyle changes (e.g. driving) along with therapy adjustments as Park Sleep patients may be sensitive to dopamine D3 active agonists, such as ropinirole and pramipexole. Specific dashboard scores based personalized management options need to be implemented and include pharmacological, non-pharmacological, and lifestyle linked advice.
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Affiliation(s)
- Phoebe Tall
- Department of Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience (IoPpn), King's College London, London, UK
- Parkinson's Foundation Centre of Excellence, King's College Hospital NHS Foundation Trust, London, UK
| | - Mubasher A Qamar
- Department of Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience (IoPpn), King's College London, London, UK
- Parkinson's Foundation Centre of Excellence, King's College Hospital NHS Foundation Trust, London, UK
| | - Ivana Rosenzweig
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPpn), King's College London, London, UK
- Sleep Disorder Centre, Nuffield House, Guy's Hospital, London, UK
| | - Vanessa Raeder
- Parkinson's Foundation Centre of Excellence, King's College Hospital NHS Foundation Trust, London, UK
- Department of Neurology and Experimental Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität, Berlin, Germany
| | - Anna Sauerbier
- Department of Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience (IoPpn), King's College London, London, UK
- Department of Neurology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Zach Heidemarie
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Cristian Falup-Pecurariu
- Faculty of Medicine, Transilvania University of Braşov, Brașov, Romania
- Department of Neurology, County Clinic Hospital, Braşov, Romania
| | - Kallol Ray Chaudhuri
- Department of Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience (IoPpn), King's College London, London, UK
- Parkinson's Foundation Centre of Excellence, King's College Hospital NHS Foundation Trust, London, UK
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Ranasinghe JC, Wang Z, Huang S. Raman Spectroscopy on Brain Disorders: Transition from Fundamental Research to Clinical Applications. BIOSENSORS 2022; 13:27. [PMID: 36671862 PMCID: PMC9855372 DOI: 10.3390/bios13010027] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/13/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
Brain disorders such as brain tumors and neurodegenerative diseases (NDs) are accompanied by chemical alterations in the tissues. Early diagnosis of these diseases will provide key benefits for patients and opportunities for preventive treatments. To detect these sophisticated diseases, various imaging modalities have been developed such as computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). However, they provide inadequate molecule-specific information. In comparison, Raman spectroscopy (RS) is an analytical tool that provides rich information about molecular fingerprints. It is also inexpensive and rapid compared to CT, MRI, and PET. While intrinsic RS suffers from low yield, in recent years, through the adoption of Raman enhancement technologies and advanced data analysis approaches, RS has undergone significant advancements in its ability to probe biological tissues, including the brain. This review discusses recent clinical and biomedical applications of RS and related techniques applicable to brain tumors and NDs.
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Stanojlovic M, Pallais JP, Kotz CM. Chemogenetic Modulation of Orexin Neurons Reverses Changes in Anxiety and Locomotor Activity in the A53T Mouse Model of Parkinson's Disease. Front Neurosci 2019; 13:702. [PMID: 31417337 PMCID: PMC6682689 DOI: 10.3389/fnins.2019.00702] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 06/21/2019] [Indexed: 01/02/2023] Open
Abstract
Parkinson’s disease (PD) is the second most common neurodegenerative disease. PD symptomology is recognized as heterogeneous and in addition to motor function decline includes cognitive, mood, sleep, and metabolic disorders. Previous studies showed early reductions in anxiety and locomotion in the A53T mice model of PD. Since inflammation and astrogliosis are an integral part of PD pathology and impair proper neuronal function, we were keen to investigate if behavioral changes in A53T mice are accompanied by increased inflammation and astrogliosis in the hippocampus (Hipp) and motor cortex (mCtx) brain regions involved in the regulation of anxiety and locomotion, respectively. To test this, we used 3-, 5-, and 7-month-old A53T mice to examine anxiety-like behavior, locomotion, and expression of inflammation and astrogliosis markers in the Hipp and mCtx. Further, we examined the presence of alpha-synuclein accumulation in orexin neurons and orexin neuronal loss. The data show early reductions in anxiety-like behavior as well as increased locomotor activity, which was accompanied by inflammation and astrogliosis in the Hipp and mCtx. Due to the persistence of the orexin neuron population in A53T mice and the involvement of orexin in anxiety and locomotor regulation, we hypothesized that chemogenetic modulation of orexin neurons would reverse the observed reductions in anxiety-like behavior and the increases in locomotor activity in these animals. We showed that chemogenetic activation of orexin neurons in A53T mice restores anxiety-like behavior back to control levels without affecting locomotor activity, whereas the inhibition of orexin neurons reverses the elevated locomotor activity without any effects on anxiety-like behavior. This study exemplifies the complex role of orexin neurons in this model of PD and demonstrates the novel finding that changes in locomotor and anxiety-like behavior are accompanied by inflammation and astrogliosis. Together, these data suggest that the orexin system may play a significant role in early and late stages of PD.
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Affiliation(s)
- Milos Stanojlovic
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States
| | - Jean Pierre Pallais
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States
| | - Catherine M Kotz
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States.,Minneapolis VA Health Care System, Geriatric Research, Education and Clinical Center, Minneapolis, MN, United States
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Stanojlovic M, Pallais Yllescas JP, Vijayakumar A, Kotz C. Early Sociability and Social Memory Impairment in the A53T Mouse Model of Parkinson's Disease Are Ameliorated by Chemogenetic Modulation of Orexin Neuron Activity. Mol Neurobiol 2019; 56:8435-8450. [PMID: 31250383 DOI: 10.1007/s12035-019-01682-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/14/2019] [Indexed: 02/08/2023]
Abstract
Parkinson's disease (PD) is a multi-layered progressive neurodegenerative disease. Signature motor system impairments are accompanied by a variety of other symptoms such as mood, sleep, metabolic, and cognitive disorders. Interestingly, social cognition impairments can be observed from the earliest stages of the disease, prior to the onset of the motor symptoms. In this study, we investigated age-related reductions in sociability and social memory in the A53T mouse model of PD. Since inflammation and astrogliosis are an integral part of PD pathology and impair proper neuronal function, we examined astrogliosis and inflammation markers and parvalbumin expression in medial pre-frontal cortex (mPFC), part of the brain responsible for social cognition regulation. Finally, we used DREADDs (Designer Receptors Exclusively Activated by Designer Drugs) for the stimulation and inhibition of orexin neuronal activity to modulate sociability and social memory in A53T mice. We observed that social cognition impairment in A53T mice is accompanied by an increase in astrogliosis and inflammation markers, in addition to loss of parvalbumin neurons and inhibitory pre-synaptic terminals in the mPFC. Moreover, DREADD-induced activation of orexin neurons restores social cognition in the A53T mouse model of PD. SIGNIFICANCE STATEMENT: Social cognition is severely affected in the early stages of Parkinson's disease. In this study, we identified the A53T mouse as a model of social cognitive impairment in PD. Observed alterations in sociability and social memory are accompanied by loss of parvalbumin positive neurons and loss of inhibitory input to mPFC. Stimulating orexin neurons using a chemogenetic approach (DREADDs) ameliorated social cognitive impairment. This study identifies a role for orexin neurons in social cognition in PD and suggests potential therapeutic targets for PD-related social cognition impairments.
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Affiliation(s)
- Milos Stanojlovic
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA.
| | | | - Aarthi Vijayakumar
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Catherine Kotz
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA.,GRECC, Minneapolis VA Health Care System, Minneapolis, MN, USA
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Emamzadeh FN, Surguchov A. Parkinson's Disease: Biomarkers, Treatment, and Risk Factors. Front Neurosci 2018; 12:612. [PMID: 30214392 PMCID: PMC6125353 DOI: 10.3389/fnins.2018.00612] [Citation(s) in RCA: 296] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 08/13/2018] [Indexed: 12/14/2022] Open
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder caused mainly by lack of dopamine in the brain. Dopamine is a neurotransmitter involved in movement, motivation, memory, and other functions; its level is decreased in PD brain as a result of dopaminergic cell death. Dopamine loss in PD brain is a cause of motor deficiency and, possibly, a reason of the cognitive deficit observed in some PD patients. PD is mostly not recognized in its early stage because of a long latency between the first damage to dopaminergic cells and the onset of clinical symptoms. Therefore, it is very important to find reliable molecular biomarkers that can distinguish PD from other conditions, monitor its progression, or give an indication of a positive response to a therapeutic intervention. PD biomarkers can be subdivided into four main types: clinical, imaging, biochemical, and genetic. For a long time protein biomarkers, dopamine metabolites, amino acids, etc. in blood, serum, cerebrospinal liquid (CSF) were considered the most promising. Among the candidate biomarkers that have been tested, various forms of α-synuclein (α-syn), i.e., soluble, aggregated, post-translationally modified, etc. were considered potentially the most efficient. However, the encouraging recent results suggest that microRNA-based analysis may bring considerable progress, especially if it is combined with α-syn data. Another promising analysis is the advanced metabolite profiling of body fluids, called "metabolomics" which may uncover metabolic fingerprints specific for various stages of PD. Conventional pharmacological treatment of PD is based on the replacement of dopamine using dopamine precursors (levodopa, L-DOPA, L-3,4 dihydroxyphenylalanine), dopamine agonists (amantadine, apomorphine) and MAO-B inhibitors (selegiline, rasagiline), which can be used alone or in combination with each other. Potential risk factors include environmental toxins, drugs, pesticides, brain microtrauma, focal cerebrovascular damage, and genomic defects. This review covers molecules that might act as the biomarkers of PD. Then, PD risk factors (including genetics and non-genetic factors) and PD treatment options are discussed.
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Affiliation(s)
- Fatemeh N. Emamzadeh
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, University of Lancaster, Lancaster, United Kingdom
| | - Andrei Surguchov
- Department of Neurology, Kansas University Medical Center, Kansas City, KS, United States
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