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Movement Disorders : Official Journal... Mar 2022α-synucleinopathies, encompassing Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy, are devastating neurodegenerative diseases for which... (Review)
Review
α-synucleinopathies, encompassing Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy, are devastating neurodegenerative diseases for which available therapeutic options are scarce, mostly because of our limited understanding of their pathophysiology. Although these pathologies are attributed to an intracellular accumulation of the α-synuclein protein in the nervous system with subsequent neuronal loss, the trigger(s) of this accumulation is/are not clearly identified. Among the existing hypotheses, interest in the hypothesis advocating the involvement of infectious agents in the onset of these diseases is renewed. In this article, we aimed to review the ongoing relevant factors favoring and opposing this hypothesis, focusing on (1) the potential antimicrobial role of α-synuclein, (2) potential entry points of pathogens in regard to early symptoms of diverse α-synucleinopathies, (3) pre-existing literature reviews assessing potential associations between infectious agents and Parkinson's disease, (4) original studies assessing these associations for dementia with Lewy bodies and multiple system atrophy (identified through a systematic literature review), and finally (5) potential susceptibility factors modulating the effects of infectious agents on the nervous system. © 2022 International Parkinson and Movement Disorder Society.
Topics: Humans; Lewy Body Disease; Multiple System Atrophy; Parkinson Disease; Synucleinopathies; alpha-Synuclein
PubMed: 35040520
DOI: 10.1002/mds.28925 -
Frontiers in Molecular Neuroscience 2016Growing evidence suggests that increased levels of α-synuclein might contribute to the pathogenesis of Parkinson's disease (PD) and therefore, it is crucial to... (Review)
Review
Growing evidence suggests that increased levels of α-synuclein might contribute to the pathogenesis of Parkinson's disease (PD) and therefore, it is crucial to understand the mechanisms underlying α-synuclein expression. Recently, microRNAs (miRNAs) have emerged as key regulators of gene expression involved in several diseases such as PD and other neurodegenerative disorders. A systematic literature search was performed here to identify microRNAs that directly or indirectly impact in α-synuclein expression/accumulation and describe its mechanism of action. A total of 27 studies were incorporated in the review article showing evidences that six microRNAs directly bind and regulate α-synuclein expression while several miRNAs impact on α-synuclein expression indirectly by targeting other genes. In turn, α-synuclein overexpression also impacts miRNAs expression, indicating the complex network between miRNAs and α-synuclein. From the current knowledge on the central role of α-synuclein in PD pathogenesis/progression, miRNAs are likely to play a crucial role at different stages of PD and might potentially be considered as new PD therapeutic approaches.
PubMed: 27917109
DOI: 10.3389/fnmol.2016.00128 -
Annals of Palliative Medicine Dec 2022There is no consensus on the efficacy of using α-synuclein as the primary immunotherapy site for Parkinson's disease (PD). The present study sought to investigate the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
There is no consensus on the efficacy of using α-synuclein as the primary immunotherapy site for Parkinson's disease (PD). The present study sought to investigate the safety and effectiveness of α-synuclein immunotherapy for treating PD.
METHODS
The databases of CNKI, CBM, Cochrane Library, PubMed, Web of Science, and Embase were searched for randomized controlled trials (RCTs). Cochrane Collaboration's bias assessment tool was used to assess the risk of bias in the included articles, and the included PD patients older than 18 years adopted immunotherapy. Stata 15.0 was employed for statistical analysis.
RESULTS
A total of 6 RCTs were eligible for the present study, involving 606 immunotherapy recipients (using alpha-synuclein immunotherapy) and 254 control individuals (placebo). Our meta-analysis found no statistical difference in the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) total score [weighted mean difference (WMD): -0.72, 95% confidence interval (CI): -1.56 to 0.13, P=0.099], adverse event incidence [relative risk (RR): 1.06, 95% CI: 0.98 to 1.15, P=0.150], headache incidence (RR: 0.95, 95% CI: 0.67 to 1.34, P=0.773), and constipation incidence (RR: 1.47, 95% CI: 0.77 to 2.78, P=0.242). However, the infection rate in the immunotherapy group was higher than in the control group (RR: 2.29, 95% CI: 1.40 to 3.74, P=0.003). The above results indicate that immunotherapy is significantly different from placebo in MDS-UPDRS and adverse event incidence, but it can reduce the incidence of infection rate.
CONCLUSIONS
Existing results showed that α-synuclein immunotherapy had no significant effect on PD. high-quality, multi-center, and large-scale clinical studies are desired to corroborate our findings.
Topics: Humans; Parkinson Disease; alpha-Synuclein; Immunotherapy
PubMed: 36636001
DOI: 10.21037/apm-22-1356 -
Biomedicine & Pharmacotherapy =... Sep 2023Neurodegenerative diseases (NDDs) encompass a range of conditions that involve progressive deterioration and dysfunction of the nervous system. Some of the common NDDs... (Review)
Review
Neurodegenerative diseases (NDDs) encompass a range of conditions that involve progressive deterioration and dysfunction of the nervous system. Some of the common NDDs include Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS). Although significant progress has been made in understanding the pathological mechanisms of NDDs in recent years, the development of targeted and effective drugs for their treatment remains challenging. Kaempferol is a flavonoid whose derivatives include kaempferol-O-rhamnoside, 3-O-β-rutinoside/6-hydroxykaempferol 3,6-di-O-β-d-glucoside, and kaempferide. Emerging studies have suggested that kaempferol and its derivatives possess neuroprotective properties and may have potential therapeutic benefits in NDDs. Here, we aimed to provide a theoretical basis for the use of kaempferol and its derivatives in the clinical treatment of NDDs. We systematically reviewed the literature in the PubMed, Web of Science, and Science Direct databases until June 2022 using the search terms "kaempferol," "kaempferol derivatives," "NDDs," "pharmacokinetics," and "biosynthesis" according to the reporting items for systematic review (PRISMA) standard. Based on combined results of in vivo and in vitro studies, we summarize the basic mechanisms and targets of kaempferol and its derivatives in the management of AD, PD, HD, and ALS. Kaempferol and its derivatives exert a neuroprotective role mainly by preventing the deposition of amyloid fibrils (such as Aβ, tau, and α-synuclein), inhibiting microglia activation, reducing the release of inflammatory factors, restoring the mitochondrial membrane to prevent oxidative stress, protecting the blood-brain barrier, and inhibiting specific enzyme activities (such as cholinesterase). Kaempferol and its derivatives are promising natural neuroprotective agents. By determining their pharmacological mechanism, kaempferol and its derivatives may be new candidate drugs for the treatment of NDDs.
Topics: Humans; Neurodegenerative Diseases; Neuroprotective Agents; Amyotrophic Lateral Sclerosis; Kaempferols; Alzheimer Disease; Parkinson Disease; Huntington Disease
PubMed: 37494786
DOI: 10.1016/j.biopha.2023.115215 -
Movement Disorders : Official Journal... Jun 2012Pathological data from autopsies genotyped for Parkinson's disease (PD)-related mutations in alpha-synuclein, Parkin, PINK1, DJ1, LRRK2, and glucocerebrosidase have... (Review)
Review
Pathological data from autopsies genotyped for Parkinson's disease (PD)-related mutations in alpha-synuclein, Parkin, PINK1, DJ1, LRRK2, and glucocerebrosidase have accumulated in recent years. The aim of this review is to systematically review all pathological reports of mutation carriers and to identify pathological patterns and gaps in the currently available data. A systematic review of the English literature was done using the terms "Parkinson's disease," "brain pathology," "autopsy," the specific gene nomenclature, and any combination of the above. Most studies included reports of convenience samples: either cases that were preidentified as mutation carriers before autopsy or screens of Lewy body brain banks. Nineteen autopsies of alpha-synuclein mutation carriers, 49 of LRRK2 mutation carriers, nine of Parkin mutation carriers, one of a PINK1 mutation carrier, and 86 of glucocerebrosidase mutation carriers were identified. Most autopsies of alpha-synuclein, LRRK2 G2019S, and glucocerebrosidase mutation carriers demonstrated Lewy body pathology, as opposed to Parkin and LRRK2 non-G2019S mutation carriers. However, there was a marked variability in pathological findings, even among carriers of identical mutations. Pathological data from DJ1 mutation carriers, nonmanifesting mutation carriers (e.g., of LRRK2 mutations), and carriers of a single Parkin mutation were lacking. In gathering together all studies of PD autopsies with an identified genetic risk, this review highlights the wealth of information generated as well as shortcomings in the available data. In particular, there is a need for larger, unbiased pathological studies. Differential association of Lewy pathology with specific mutations may reflect heterogeneity in pathogenic mechanisms among the different PD-related genes.
Topics: Animals; Brain; Genetic Predisposition to Disease; Humans; Mutation; Nerve Tissue Proteins; Parkinson Disease
PubMed: 22451330
DOI: 10.1002/mds.24962 -
Biomedicines Jul 2022Extracellular plaques composed of the hydrophobic peptide amyloid-β and intraneuronal accumulation of the hyperphosphorylated protein tau (p-tau) are pathological... (Review)
Review
Extracellular plaques composed of the hydrophobic peptide amyloid-β and intraneuronal accumulation of the hyperphosphorylated protein tau (p-tau) are pathological hallmarks found in the brains of most people affected by Alzheimer's disease (AD). In Parkinson's disease (PD), Lewy bodies, i.e., intraneuronal protein deposits comprising the protein α-synuclein, are a typical disease feature. As these hallmarks located in the brain are hardly traceable, reliable biomarkers from easily accessible body fluids are key for accurate diagnosis. The aim of the present work was to review the available literature regarding potential biomarkers of AD and PD in the saliva. The databases PubMed, Google Scholar, LILACS, LIVIVO, VHL regional portal, Cochrane Library, eLIBRARY, and IOS Press were consulted for the literature search. Screening of titles and abstracts followed the PRISMA guidelines, while data extraction and the assessment of full texts were carried out in accordance with the Newcastle-Ottawa Scale assessment. The review shows significant increases in levels of the amyloid-β Aβ1-42 and elevated p-tau to total tau (t-tau) ratios in salivary samples of AD patients, in comparison with healthy controls. In PD patients, levels of α-synuclein in salivary samples significantly decreased compared to healthy controls, whereas oligomeric α-synuclein and the ratio of oligomeric α-synuclein to total α-synuclein markedly increased. Salivary biomarkers represent a promising diagnostic tool for neurodegenerative diseases. Further high-quality case-control studies are needed to substantiate their accuracy.
PubMed: 35885007
DOI: 10.3390/biomedicines10071702 -
Cells Feb 2024Parkinson's Disease (PD) is a common neurodegenerative disease which manifests with motor features, such as bradykinesia, resting tremor, rigidity, and postural... (Meta-Analysis)
Meta-Analysis Review
Parkinson's Disease (PD) is a common neurodegenerative disease which manifests with motor features, such as bradykinesia, resting tremor, rigidity, and postural instability. Using the non-invasive technique of saliva collection, we designed a systematic review to answer the question "Are salivary biomarkers reliable for the diagnosis of Parkinson's Disease?". Following inclusion and exclusion criteria, 30 studies were included in this systematic review (according to the PRISMA statement guidelines). Mostly proteins were reported as potential biomarkers in saliva. Based on meta-analysis, in PD patients, salivary levels of total alpha-synuclein were significantly decreased, and those of oligomeric alpha-synuclein were significantly increased. Also, according to pooled AUC, heme oxygenase-1 demonstrated significant predictive value for saliva-based PD diagnosis. In conclusion, some potential biomarkers, especially alpha-synuclein, can be altered in the saliva of PD patients, which could be reliably useful for early diagnosis of this neurodegenerative disease differentiating other synucleopathies.
Topics: Humans; Parkinson Disease; alpha-Synuclein; Neurodegenerative Diseases; Saliva; Biomarkers
PubMed: 38391952
DOI: 10.3390/cells13040340 -
International Journal of Molecular... Jul 2023Inflammatory mechanisms are increasingly recognized as important contributors to the pathogenesis of neurodegenerative diseases, including Lewy body dementia (LBD). Our... (Review)
Review
Inflammatory mechanisms are increasingly recognized as important contributors to the pathogenesis of neurodegenerative diseases, including Lewy body dementia (LBD). Our objectives were to, firstly, review inflammation investigation methods in LBD (dementia with Lewy bodies and Parkinson's disease dementia) and, secondly, identify alterations in inflammatory signals in LBD compared to people without neurodegenerative disease and other neurodegenerative diseases. A systematic scoping review was performed by searching major electronic databases (MEDLINE, Embase, Web of Science, and PSYCHInfo) to identify relevant human studies. Of the 2509 results screened, 80 studies were included. Thirty-six studies analyzed postmortem brain tissue, and 44 investigated living subjects with cerebrospinal fluid, blood, and/or brain imaging assessments. Largely cross-sectional data were available, although two longitudinal clinical studies investigated prodromal Lewy body disease. Investigations were focused on inflammatory immune cell activity (microglia, astrocytes, and lymphocytes) and inflammatory molecules (cytokines, etc.). Results of the included studies identified innate and adaptive immune system contributions to inflammation associated with Lewy body pathology and clinical disease features. Different signals in early and late-stage disease, with possible late immune senescence and dystrophic glial cell populations, were identified. The strength of these associations is limited by the varying methodologies, small study sizes, and cross-sectional nature of the data. Longitudinal studies investigating associations with clinical and other biomarker outcomes are needed to improve understanding of inflammatory activity over the course of LBD. This could identify markers of disease activity and support therapeutic development.
Topics: Humans; Lewy Body Disease; Dementia; Neurodegenerative Diseases; Cross-Sectional Studies; Parkinson Disease; Inflammation; alpha-Synuclein
PubMed: 37569491
DOI: 10.3390/ijms241512116 -
Cureus Oct 2022Neurodegenerative diseases, in particular Parkinson's disease (PD), a disabling disorder, require early attention due to the course the diseases take. By the time of... (Review)
Review
Neurodegenerative diseases, in particular Parkinson's disease (PD), a disabling disorder, require early attention due to the course the diseases take. By the time of clinical manifestation, dopaminergic neuron death would have already exceeded a damaging level. Therefore, the discovery of biomarkers that will effectively diagnose PD at an early stage and help monitor disease advancement is crucial. Out of the available biomarkers and bodily sources from which these can be isolated; alpha-synuclein (a-syn) from saliva seems to be a promising and easily accessible option. This has been further investigated in this systematic review. A comprehensive literature search on PubMed, PubMed Central (PMC), and Science Direct resulted in 1,439 articles. After screening and exclusion, 12 relevant articles were derived. In many of the studies, there was a decrease in total salivary a-syn in PD patients compared to healthy controls (HC), with an increase in oligo a-syn and oligo a-syn/total a-syn ratio as a rather consistent finding amongst the studies reviewed. On the other hand, a few studies revealed no significant difference in a-syn levels between the controls and PD patients. Another common finding was the lack of disease severity correlation with the marker, probably due to the scarcity of longitudinal studies conducted and smaller cohorts recruited in the studies. Overall, the total a-syn did show a genetic and phenotypic association, whilst oligo a-syn had the potential to serve as a biomarker for disease diagnosis. With the standardization of sample collection methods and diagnostic tools, and the accomplishment of longitudinal studies, further importance of salivary a-syn as a biomarker in PD could be established, utilizing the already existing data as an encouraging foundation for future research.
PubMed: 36348879
DOI: 10.7759/cureus.29880 -
Neural Regeneration Research Dec 2024The search for reliable and easily accessible biomarkers in Parkinson's disease is receiving a growing emphasis, to detect neurodegeneration from the prodromal phase and...
The search for reliable and easily accessible biomarkers in Parkinson's disease is receiving a growing emphasis, to detect neurodegeneration from the prodromal phase and to enforce disease-modifying therapies. Despite the need for non-invasively accessible biomarkers, the majority of the studies have pointed to cerebrospinal fluid or peripheral biopsies biomarkers, which require invasive collection procedures. Saliva represents an easily accessible biofluid and an incredibly wide source of molecular biomarkers. In the present study, after presenting the morphological and biological bases for looking at saliva in the search of biomarkers for Parkinson's disease, we systematically reviewed the results achieved so far in the saliva of different cohorts of Parkinson's disease patients. A comprehensive literature search on PubMed and SCOPUS led to the discovery of 289 articles. After screening and exclusion, 34 relevant articles were derived for systematic review. Alpha-synuclein, the histopathological hallmark of Parkinson's disease, has been the most investigated Parkinson's disease biomarker in saliva, with oligomeric alpha-synuclein consistently found increased in Parkinson's disease patients in comparison to healthy controls, while conflicting results have been reported regarding the levels of total alpha-synuclein and phosphorylated alpha-synuclein, and few studies described an increased oligomeric alpha-synuclein/total alpha-synuclein ratio in Parkinson's disease. Beyond alpha-synuclein, other biomarkers targeting different molecular pathways have been explored in the saliva of Parkinson's disease patients: total tau, phosphorylated tau, amyloid-β1-42 (pathological protein aggregation biomarkers); DJ-1, heme-oxygenase-1, metabolites (altered energy homeostasis biomarkers); MAPLC-3beta (aberrant proteostasis biomarker); cortisol, tumor necrosis factor-alpha (inflammation biomarkers); DNA methylation, miRNA (DNA/RNA defects biomarkers); acetylcholinesterase activity (synaptic and neuronal network dysfunction biomarkers); Raman spectra, proteome, and caffeine. Despite a few studies investigating biomarkers targeting molecular pathways different from alpha-synuclein in Parkinson's disease, these results should be replicated and observed in studies on larger cohorts, considering the potential role of these biomarkers in determining the molecular variance among Parkinson's disease subtypes. Although the need for standardization in sample collection and processing, salivary-based biomarkers studies have reported encouraging results, calling for large-scale longitudinal studies and multicentric assessments, given the great molecular potentials and the non-invasive accessibility of saliva.
PubMed: 38595280
DOI: 10.4103/NRR.NRR-D-23-01677