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Leak RK, Clark RN, Abbas M, Xu F, Brodsky JL, Chen J, Hu X, Luk KC. Current insights and assumptions on α-synuclein in Lewy body disease. Acta Neuropathol 2024; 148:18. [PMID: 39141121 PMCID: PMC11324801 DOI: 10.1007/s00401-024-02781-3] [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: 07/05/2024] [Revised: 07/28/2024] [Accepted: 08/04/2024] [Indexed: 08/15/2024]
Abstract
Lewy body disorders are heterogeneous neurological conditions defined by intracellular inclusions composed of misshapen α-synuclein protein aggregates. Although α-synuclein aggregates are only one component of inclusions and not strictly coupled to neurodegeneration, evidence suggests they seed the propagation of Lewy pathology within and across cells. Genetic mutations, genomic multiplications, and sequence polymorphisms of the gene encoding α-synuclein are also causally linked to Lewy body disease. In nonfamilial cases of Lewy body disease, the disease trigger remains unidentified but may range from industrial/agricultural toxicants and natural sources of poisons to microbial pathogens. Perhaps due to these peripheral exposures, Lewy inclusions appear at early disease stages in brain regions connected with cranial nerves I and X, which interface with inhaled and ingested environmental elements in the nasal or gastrointestinal cavities. Irrespective of its identity, a stealthy disease trigger most likely shifts soluble α-synuclein (directly or indirectly) into insoluble, cross-β-sheet aggregates. Indeed, β-sheet-rich self-replicating α-synuclein multimers reside in patient plasma, cerebrospinal fluid, and other tissues, and can be subjected to α-synuclein seed amplification assays. Thus, clinicians should be able to capitalize on α-synuclein seed amplification assays to stratify patients into potential responders versus non-responders in future clinical trials of α-synuclein targeted therapies. Here, we briefly review the current understanding of α-synuclein in Lewy body disease and speculate on pathophysiological processes underlying the potential transmission of α-synucleinopathy across the neuraxis.
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Affiliation(s)
- Rehana K Leak
- Graduate School of Pharmaceutical Sciences, Duquesne University, 418C Mellon Hall, 913 Bluff Street, Pittsburgh, PA, 15219, USA.
| | - Rachel N Clark
- Graduate School of Pharmaceutical Sciences, Duquesne University, 418C Mellon Hall, 913 Bluff Street, Pittsburgh, PA, 15219, USA
| | - Muslim Abbas
- Graduate School of Pharmaceutical Sciences, Duquesne University, 418C Mellon Hall, 913 Bluff Street, Pittsburgh, PA, 15219, USA
| | - Fei Xu
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jun Chen
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, Pennsylvania, USA
| | - Xiaoming Hu
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kelvin C Luk
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Pennsylvania, PA, USA
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Venuto CS, Herbst K, Chahine LM, Kieburtz K. Predicting Cerebrospinal Fluid Alpha-Synuclein Seed Amplification Assay Status from Demographics and Clinical Data. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.08.07.24311578. [PMID: 39148857 PMCID: PMC11326325 DOI: 10.1101/2024.08.07.24311578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Objective To develop and externally validate models to predict probabilities of alpha-synuclein (a-syn) positive or negative status in vivo in a mixture of people with and without Parkinson's disease (PD) using easily accessible clinical predictors. Methods Uni- and multi-variable logistic regression models were developed in a cohort of participants from the Parkinson Progression Marker Initiative (PPMI) study to predict cerebrospinal fluid (CSF) a-syn status as measured by seeding amplification assay (SAA). Models were externally validated in a cohort of participants from the Systemic Synuclein Sampling Study (S4) that had also measured CSF a-syn status using SAA. Results The PPMI model training/testing cohort consisted of 1260 participants, of which 76% had manifest PD with a mean (± standard deviation) disease duration of 1.2 (±1.6) years. Overall, 68.7% of the overall PPMI cohort (and 88.0% with PD of those with manifest PD) had positive CSF a-syn SAA status results. Variables from the full multivariable model to predict CSF a-syn SAA status included age-and sex-specific University of Pennsylvania Smell Identification Test (UPSIT) percentile values, sex, self-reported presence of constipation problems, leucine-rich repeat kinase 2 ( LRRK2 ) genetic status and pathogenic variant, and GBA status. Internal performance of the model on PPMI data to predict CSF a-syn SAA status had an area under the receiver operating characteristic curve (AUROC) of 0.920, and sensitivity/specificity of 0.881/0.845. When this model was applied to the external S4 cohort, which included 71 participants (70.4% with manifest PD for a mean 5.1 (±4.8) years), it performed well, achieving an AUROC of 0.976, and sensitivity/specificity of 0.958/0.870. Models using only UPSIT percentile performed similarly well upon internal and external testing. Conclusion Data-driven models using non-invasive clinical features can accurately predict CSF a-syn SAA positive and negative status in cohorts enriched for people living with PD. Scores from the UPSIT were highly significant in predicting a-syn SAA status.
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Kwok DK. Parkinson's disease: Still waiting for a cure. Clin Transl Sci 2024; 17:e13898. [PMID: 39046375 PMCID: PMC11267978 DOI: 10.1111/cts.13898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 07/03/2024] [Accepted: 07/06/2024] [Indexed: 07/25/2024] Open
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Wyman-Chick KA, Chaudhury P, Bayram E, Abdelnour C, Matar E, Chiu SY, Ferreira D, Hamilton CA, Donaghy PC, Rodriguez-Porcel F, Toledo JB, Habich A, Barrett MJ, Patel B, Jaramillo-Jimenez A, Scott GD, Kane JPM. Differentiating Prodromal Dementia with Lewy Bodies from Prodromal Alzheimer's Disease: A Pragmatic Review for Clinicians. Neurol Ther 2024; 13:885-906. [PMID: 38720013 PMCID: PMC11136939 DOI: 10.1007/s40120-024-00620-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/05/2024] [Indexed: 05/12/2024] Open
Abstract
This pragmatic review synthesises the current understanding of prodromal dementia with Lewy bodies (pDLB) and prodromal Alzheimer's disease (pAD), including clinical presentations, neuropsychological profiles, neuropsychiatric symptoms, biomarkers, and indications for disease management. The core clinical features of dementia with Lewy bodies (DLB)-parkinsonism, complex visual hallucinations, cognitive fluctuations, and REM sleep behaviour disorder are common prodromal symptoms. Supportive clinical features of pDLB include severe neuroleptic sensitivity, as well as autonomic and neuropsychiatric symptoms. The neuropsychological profile in mild cognitive impairment attributable to Lewy body pathology (MCI-LB) tends to include impairment in visuospatial skills and executive functioning, distinguishing it from MCI due to AD, which typically presents with impairment in memory. pDLB may present with cognitive impairment, psychiatric symptoms, and/or recurrent episodes of delirium, indicating that it is not necessarily synonymous with MCI-LB. Imaging, fluid and other biomarkers may play a crucial role in differentiating pDLB from pAD. The current MCI-LB criteria recognise low dopamine transporter uptake using positron emission tomography or single photon emission computed tomography (SPECT), loss of REM atonia on polysomnography, and sympathetic cardiac denervation using meta-iodobenzylguanidine SPECT as indicative biomarkers with slowing of dominant frequency on EEG among others as supportive biomarkers. This review also highlights the emergence of fluid and skin-based biomarkers. There is little research evidence for the treatment of pDLB, but pharmacological and non-pharmacological treatments for DLB may be discussed with patients. Non-pharmacological interventions such as diet, exercise, and cognitive stimulation may provide benefit, while evaluation and management of contributing factors like medications and sleep disturbances are vital. There is a need to expand research across diverse patient populations to address existing disparities in clinical trial participation. In conclusion, an early and accurate diagnosis of pDLB or pAD presents an opportunity for tailored interventions, improved healthcare outcomes, and enhanced quality of life for patients and care partners.
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Affiliation(s)
- Kathryn A Wyman-Chick
- Struthers Parkinson's Center and Center for Memory and Aging, Department of Neurology, HealthPartners/Park Nicollet, Bloomington, USA.
| | - Parichita Chaudhury
- Cleo Roberts Memory and Movement Center, Banner Sun Health Research Institute, Sun City, USA
| | - Ece Bayram
- Parkinson and Other Movement Disorders Center, University of California San Diego, San Diego, USA
| | - Carla Abdelnour
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Palo Alto, USA
| | - Elie Matar
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Shannon Y Chiu
- Department of Neurology, Mayo Clinic Arizona, Phoenix, USA
| | - Daniel Ferreira
- Division of Clinical Geriatrics, Center for Alzheimer Research, Karolinska Institute, Solna, Sweden
- Department of Radiology, Mayo Clinic Rochester, Rochester, USA
- Facultad de Ciencias de la Salud, Universidad Fernando Pessoa Canarias, Las Palmas, Spain
| | - Calum A Hamilton
- Translational and Clinical Research Institute, Newcastle University, Newcastle Upon Tyne, UK
| | - Paul C Donaghy
- Translational and Clinical Research Institute, Newcastle University, Newcastle Upon Tyne, UK
| | | | - Jon B Toledo
- Nantz National Alzheimer Center, Stanley Appel Department of Neurology, Houston Methodist Hospital, Houston, USA
| | - Annegret Habich
- Division of Clinical Geriatrics, Center for Alzheimer Research, Karolinska Institute, Solna, Sweden
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Matthew J Barrett
- Department of Neurology, Parkinson's and Movement Disorders Center, Virginia Commonwealth University, Richmond, USA
| | - Bhavana Patel
- Department of Neurology, College of Medicine, University of Florida, Gainesville, USA
- Norman Fixel Institute for Neurologic Diseases, University of Florida, Gainesville, USA
| | - Alberto Jaramillo-Jimenez
- Centre for Age-Related Medicine, Stavanger University Hospital, Stavanger, Norway
- School of Medicine, Grupo de Neurociencias de Antioquia, Universidad de Antioquia, Medellín, Colombia
| | - Gregory D Scott
- Department of Pathology and Laboratory Services, VA Portland Medical Center, Portland, USA
| | - Joseph P M Kane
- Centre for Public Health, Queen's University Belfast, Belfast, UK
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Espay AJ, Lees AJ. Loss of monomeric alpha-synuclein (synucleinopenia) and the origin of Parkinson's disease. Parkinsonism Relat Disord 2024; 122:106077. [PMID: 38461037 DOI: 10.1016/j.parkreldis.2024.106077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/11/2024]
Abstract
These facts argue against the gain-of-function synucleinopathy hypothesis, which proposes that Lewy pathology causes Parkinson's disease: (1) most brains from people without neurological symptoms have multiple pathologies; (2) neither pathology type nor distribution correlate with disease severity or progression in Parkinson's disease; (3) aggregated α-synuclein in the form of Lewy bodies is not a space-occupying lesion but the insoluble fraction of its precursor, soluble monomeric α-synuclein; (4) pathology spread is passive, occurring by irreversible nucleation, not active replication; and (5) low cerebrospinal fluid α-synuclein levels predict brain atrophy and clinical disease progression. The transformation of α-synuclein into Lewy pathology may occur as a response to biological, toxic, or infectious stressors whose persistence perpetuates the nucleation process, depleting normal α-synuclein and eventually leading to Parkinson's symptoms from neuronal death. We propose testing the loss-of-function synucleinopenia hypothesis by evaluating the clinical and neurodegenerative rescue effect of replenishing the levels of monomeric α-synuclein.
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Affiliation(s)
- Alberto J Espay
- James J. and Joan A. Gardner Family Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, Cincinnati, OH, USA.
| | - Andrew J Lees
- The National Hospital, Queen Square and Reta Lila Weston Institute for Neurological Studies University College London, London, UK
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Painous C, Fernández M, Pérez J, de Mena L, Cámara A, Compta Y. Fluid and tissue biomarkers in Parkinson's disease: Immunodetection or seed amplification? Central or peripheral? Parkinsonism Relat Disord 2024; 121:105968. [PMID: 38168618 DOI: 10.1016/j.parkreldis.2023.105968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/10/2023] [Accepted: 12/18/2023] [Indexed: 01/05/2024]
Abstract
Over the last two decades there have been meaningful developments on biomarkers of neurodegenerative diseases, extensively (but not solely) focusing on their proteinopathic nature. Accordingly, in Alzheimer's disease determination of levels of total and phosphorylated tau (τ and p-τ, usually p-τ181) along with amyloid-beta1-42 (Aβ1-42) by immunodetection in cerebrospinal fluid (CSF) and currently even in peripheral blood, have been widely accepted and introduced to routine diagnosis. In the case of Parkinson's disease, α-synuclein as a potential biomarker (both for diagnosis and progression tracking) has proved more elusive under the immunodetection approach. In recent years, the emergence of the so-called seed amplification assays is proving to be a game-changer, with mounting evidence under different technical approaches and using a variety of biofluids or tissues, yielding promising diagnostic accuracies. Currently the least invasive but at once more reliable source of biosamples and techniques are being sought. Here we overview these advances.
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Affiliation(s)
- Celia Painous
- Parkinson's Disease & Movement Disorders Unit, Neurology Service, Hospital Clínic i Universitari de Barcelona, Lab of Parkinson Disease and Other Neurodegenerative Movement Disorders - Clinical and Experimental Research, IDIBAPS, Institut de Neurociències UBNeuro, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Manel Fernández
- Parkinson's Disease & Movement Disorders Unit, Neurology Service, Hospital Clínic i Universitari de Barcelona, Lab of Parkinson Disease and Other Neurodegenerative Movement Disorders - Clinical and Experimental Research, IDIBAPS, Institut de Neurociències UBNeuro, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Jesica Pérez
- Parkinson's Disease & Movement Disorders Unit, Neurology Service, Hospital Clínic i Universitari de Barcelona, Lab of Parkinson Disease and Other Neurodegenerative Movement Disorders - Clinical and Experimental Research, IDIBAPS, Institut de Neurociències UBNeuro, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Lorena de Mena
- Parkinson's Disease & Movement Disorders Unit, Neurology Service, Hospital Clínic i Universitari de Barcelona, Lab of Parkinson Disease and Other Neurodegenerative Movement Disorders - Clinical and Experimental Research, IDIBAPS, Institut de Neurociències UBNeuro, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Ana Cámara
- Parkinson's Disease & Movement Disorders Unit, Neurology Service, Hospital Clínic i Universitari de Barcelona, Lab of Parkinson Disease and Other Neurodegenerative Movement Disorders - Clinical and Experimental Research, IDIBAPS, Institut de Neurociències UBNeuro, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Yaroslau Compta
- Parkinson's Disease & Movement Disorders Unit, Neurology Service, Hospital Clínic i Universitari de Barcelona, Lab of Parkinson Disease and Other Neurodegenerative Movement Disorders - Clinical and Experimental Research, IDIBAPS, Institut de Neurociències UBNeuro, Universitat de Barcelona, Barcelona, Catalonia, Spain.
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Mu L, Chen J, Li J, Nyirenda T, Hegland KW, Beach TG. Mechanisms of Swallowing, Speech and Voice Disorders in Parkinson's Disease: Literature Review with Our First Evidence for the Periperal Nervous System Involvement. Dysphagia 2024:10.1007/s00455-024-10693-3. [PMID: 38498201 DOI: 10.1007/s00455-024-10693-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 02/29/2024] [Indexed: 03/20/2024]
Abstract
The majority of patients with Parkinson's disease (PD) develop swallowing, speech, and voice (SSV) disorders. Importantly, swallowing difficulty or dysphagia and related aspiration are life-threatening conditions for PD patients. Although PD treatments have significant therapeutic effects on limb motor function, their effects on SSV disorders are less impressive. A large gap in our knowledge is that the mechanisms of SSV disorders in PD are poorly understood. PD was long considered to be a central nervous system disorder caused by the death of dopaminergic neurons in the basal ganglia. Aggregates of phosphorylated α-synuclein (PAS) underlie PD pathology. SSV disorders were thought to be caused by the same dopaminergic problem as those causing impaired limb movement; however, there is little evidence to support this. The pharynx, larynx, and tongue play a critical role in performing upper airway (UA) motor tasks and their dysfunction results in disordered SSV. This review aims to provide an overview on the neuromuscular organization patterns, functions of the UA structures, clinical features of SSV disorders, and gaps in knowledge regarding the pathophysiology underlying SSV disorders in PD, and evidence supporting the hypothesis that SSV disorders in PD could be associated, at least in part, with PAS damage to the peripheral nervous system controlling the UA structures. Determining the presence and distribution of PAS lesions in the pharynx, larynx, and tongue will facilitate the identification of peripheral therapeutic targets and set a foundation for the development of new therapies to treat SSV disorders in PD.
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Affiliation(s)
- Liancai Mu
- Upper Airway Reserch Laboratory, Center for Discovery and Innovation, Hackensack Meridian Health, 111 Ideation Way, Nutley, NJ, 07110, USA.
- Center for Discovery and Innovation, Hackensack Meridian Health, 111 Ideation Way, Nutley, NJ, 07110, USA.
| | - Jingming Chen
- Upper Airway Reserch Laboratory, Center for Discovery and Innovation, Hackensack Meridian Health, 111 Ideation Way, Nutley, NJ, 07110, USA
| | - Jing Li
- Upper Airway Reserch Laboratory, Center for Discovery and Innovation, Hackensack Meridian Health, 111 Ideation Way, Nutley, NJ, 07110, USA
| | - Themba Nyirenda
- Upper Airway Reserch Laboratory, Center for Discovery and Innovation, Hackensack Meridian Health, 111 Ideation Way, Nutley, NJ, 07110, USA
| | - Karen Wheeler Hegland
- Upper Airway Dysfunction Laboratory, M.A. Program in Communication Sciences & Disorders, Department of Speech, Language and Hearing Sciences, College of Public Health and Health Professions, University of Florida, 1225 Center Dr., Gainesville, FL, 32611, USA
| | - Thomas G Beach
- Director of Neuroscience, Director of Brain and Body Donation Program, Banner Sun Health Research Institute, 10515 West Santa Fe Dr, Sun City, AZ, 85351, USA
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Seibyl JP. α-Synuclein Seeding Amplification Assay: A Breakthrough in Diagnosing Parkinson Disease? J Nucl Med 2024; 65:174-175. [PMID: 38124209 DOI: 10.2967/jnumed.123.266191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/07/2023] [Indexed: 12/23/2023] Open
Affiliation(s)
- John P Seibyl
- Institute for Neurodegenerative Disorders and Yale University School of Medicine, New Haven, Connecticut
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Miteva D, Vasilev GV, Velikova T. Role of Specific Autoantibodies in Neurodegenerative Diseases: Pathogenic Antibodies or Promising Biomarkers for Diagnosis. Antibodies (Basel) 2023; 12:81. [PMID: 38131803 PMCID: PMC10740538 DOI: 10.3390/antib12040081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Neurodegenerative diseases (NDDs) affect millions of people worldwide. They develop due to the pathological accumulation and aggregation of various misfolded proteins, axonal and synaptic loss and dysfunction, inflammation, cytoskeletal abnormalities, defects in DNA and RNA, and neuronal death. This leads to the activation of immune responses and the release of the antibodies against them. Recently, it has become clear that autoantibodies (Aabs) can contribute to demyelination, axonal loss, and brain and cognitive dysfunction. This has significantly changed the understanding of the participation of humoral autoimmunity in neurodegenerative disorders. It is crucial to understand how neuroinflammation is involved in neurodegeneration, to aid in improving the diagnostic and therapeutic value of Aabs in the future. This review aims to provide data on the immune system's role in NDDs, the pathogenic role of some specific Aabs against molecules associated with the most common NDDs, and their potential role as biomarkers for monitoring and diagnosing NDDs. It is suggested that the autoimmune aspects of NDDs will facilitate early diagnosis and help to elucidate previously unknown aspects of the pathobiology of these diseases.
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Affiliation(s)
- Dimitrina Miteva
- Department of Genetics, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 8 Dragan Tzankov Str., 1164 Sofia, Bulgaria
- Medical Faculty, Sofia University St. Kliment Ohridski, 1 Kozyak str, 1407 Sofia, Bulgaria; (G.V.V.); (T.V.)
| | - Georgi V. Vasilev
- Medical Faculty, Sofia University St. Kliment Ohridski, 1 Kozyak str, 1407 Sofia, Bulgaria; (G.V.V.); (T.V.)
- Clinic of Neurology, Department of Emergency Medicine UMHAT “Sv. Georgi”, 4000 Plovdiv, Bulgaria
| | - Tsvetelina Velikova
- Medical Faculty, Sofia University St. Kliment Ohridski, 1 Kozyak str, 1407 Sofia, Bulgaria; (G.V.V.); (T.V.)
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Zheng Y, Li S, Yang C, Yu Z, Jiang Y, Feng T. Comparison of biospecimens for α-synuclein seed amplification assays in Parkinson's disease: A systematic review and network meta-analysis. Eur J Neurol 2023; 30:3949-3967. [PMID: 37573472 DOI: 10.1111/ene.16041] [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: 03/30/2023] [Revised: 07/23/2023] [Accepted: 08/10/2023] [Indexed: 08/14/2023]
Abstract
BACKGROUND AND PURPOSE Alpha-synuclein seed amplification assays (α-syn SAAs) are promising diagnostic methods for Parkinson's disease (PD) and other synucleinopathies. However, there is limited consensus regarding the diagnostic and differential diagnostic performance of α-syn SAAs on biofluids and peripheral tissues. METHODS A comprehensive research was performed in PubMed, Web of Science, Embase and Cochrane Library. Meta-analysis was performed using a random-effects model. A network meta-analysis based on an ANOVA model was conducted to compare the relative accuracy of α-syn SAAs with different specimens. RESULTS The pooled sensitivity and specificity of α-syn SAAs in distinguishing PD from healthy controls or non-neurodegenerative neurological controls were 0.91 (95% confidence interval [CI] 0.89-0.92) and 0.95 (95% CI 0.94-0.96) for cerebrospinal fluid (CSF); 0.91 (95% CI 0.86-0.94) and 0.92 (95% CI 0.87-0.95) for skin; 0.80 (95% CI 0.66-0.89) and 0.87 (95% CI 0.69-0.96) for submandibular gland; 0.44 (95% CI 0.30-0.59) and 0.92 (95% CI 0.79-0.98) for gastrointestinal tract; 0.79 (95% CI 0.70-0.86) and 0.88 (95% CI 0.77-0.95) for saliva; and 0.51 (95% CI 0.39-0.62) and 0.91 (95% CI 0.84-0.96) for olfactory mucosa (OM). The pooled sensitivity and specificity were 0.91 (95% CI 0.89-0.93) and 0.50 (95% CI 0.44-0.55) for CSF, 0.92 (95% CI 0.83-0.97) and 0.22 (95% CI 0.06-0.48) for skin, and 0.55 (95% CI 0.42-0.68) and 0.50 (95% CI 0.35-0.65) for OM in distinguishing PD from multiple system atrophy. The pooled sensitivity and specificity were 0.92 (95% CI 0.89-0.94) and 0.84 (95% CI 0.73-0.91) for CSF, 0.92 (95% CI 0.83-0.97) and 0.88 (95% CI 0.64-0.99) for skin and 0.63 (95% CI 0.52-0.73) and 0.86 (95% CI 0.64-0.97) for OM in distinguishing PD from progressive supranuclear palsy. The pooled sensitivity and specificity were 0.94 (95% CI 0.90-0.97) and 0.95 (95% CI 0.77-1.00) for CSF and 0.94 (95% CI 0.84-0.99) and 0.86 (95% CI 0.42-1.00) for skin in distinguishing PD from corticobasal degeneration. CONCLUSIONS α-Synuclein SAAs of CSF, skin, saliva, submandibular gland, gastrointestinal tract and OM are promising diagnostic assays for PD, with CSF and skin α-syn SAAs demonstrating higher diagnostic performance.
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Affiliation(s)
- Yuanchu Zheng
- Center for Movement Disorders, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Siming Li
- Center for Movement Disorders, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Chen Yang
- Center for Movement Disorders, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zhenwei Yu
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing, China
| | - Ying Jiang
- Center for Movement Disorders, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- China National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Tao Feng
- Center for Movement Disorders, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- China National Clinical Research Center for Neurological Diseases, Beijing, China
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Vijiaratnam N, Foltynie T. How should we be using biomarkers in trials of disease modification in Parkinson's disease? Brain 2023; 146:4845-4869. [PMID: 37536279 PMCID: PMC10690028 DOI: 10.1093/brain/awad265] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/18/2023] [Accepted: 07/22/2023] [Indexed: 08/05/2023] Open
Abstract
The recent validation of the α-synuclein seed amplification assay as a biomarker with high sensitivity and specificity for the diagnosis of Parkinson's disease has formed the backbone for a proposed staging system for incorporation in Parkinson's disease clinical studies and trials. The routine use of this biomarker should greatly aid in the accuracy of diagnosis during recruitment of Parkinson's disease patients into trials (as distinct from patients with non-Parkinson's disease parkinsonism or non-Parkinson's disease tremors). There remain, however, further challenges in the pursuit of biomarkers for clinical trials of disease modifying agents in Parkinson's disease, namely: optimizing the distinction between different α-synucleinopathies; the selection of subgroups most likely to benefit from a candidate disease modifying agent; a sensitive means of confirming target engagement; and the early prediction of longer-term clinical benefit. For example, levels of CSF proteins such as the lysosomal enzyme β-glucocerebrosidase may assist in prognostication or allow enrichment of appropriate patients into disease modifying trials of agents with this enzyme as the target; the presence of coexisting Alzheimer's disease-like pathology (detectable through CSF levels of amyloid-β42 and tau) can predict subsequent cognitive decline; imaging techniques such as free-water or neuromelanin MRI may objectively track decline in Parkinson's disease even in its later stages. The exploitation of additional biomarkers to the α-synuclein seed amplification assay will, therefore, greatly add to our ability to plan trials and assess the disease modifying properties of interventions. The choice of which biomarker(s) to use in the context of disease modifying clinical trials will depend on the intervention, the stage (at risk, premotor, motor, complex) of the population recruited and the aims of the trial. The progress already made lends hope that panels of fluid biomarkers in tandem with structural or functional imaging may provide sensitive and objective methods of confirming that an intervention is modifying a key pathophysiological process of Parkinson's disease. However, correlation with clinical progression does not necessarily equate to causation, and the ongoing validation of quantitative biomarkers will depend on insightful clinical-genetic-pathophysiological comparisons incorporating longitudinal biomarker changes from those at genetic risk with evidence of onset of the pathophysiology and those at each stage of manifest clinical Parkinson's disease.
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Affiliation(s)
- Nirosen Vijiaratnam
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Thomas Foltynie
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
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