Diagnosis of multiple system atrophy

Exploring potential circRNA biomarkers for cancers based on double-line heterogeneous graph representation learning

BACKGROUND

Compared with the time-consuming and labor-intensive for biological validation in vitro or in vivo, the computational models can provide high-quality and purposeful candidates in an instant. Existing computational models face limitations in effectively utilizing sparse local structural information for accurate predictions in circRNA-disease associations. This study addresses this challenge with a proposed method, CDA-DGRL (Prediction of CircRNA-Disease Association based on Double-line Graph Representation Learning), which employs a deep learning framework leveraging graph networks and a dual-line representation model integrating graph node features.

METHOD

CDA-DGRL comprises several key steps: initially, the integration of diverse biological information to compute integrated similarities among circRNAs and diseases, leading to the construction of a heterogeneous network specific to circRNA-disease associations. Subsequently, circRNA and disease node features are derived using sparse autoencoders. Thirdly, a graph convolutional neural network is employed to capture the local graph network structure by inputting the circRNA-disease heterogeneous network alongside node features. Fourthly, the utilization of node2vec facilitates depth-first sampling of the circRNA-disease heterogeneous network to grasp the global graph network structure, addressing issues associated with sparse raw data. Finally, the fusion of local and global graph network structures is inputted into an extra trees classifier to identify potential circRNA-disease associations.

RESULTS

The results, obtained through a rigorous five-fold cross-validation on the circR2Disease dataset, demonstrate the superiority of CDA-DGRL with an AUC value of 0.9866 and an AUPR value of 0.9897 compared to existing state-of-the-art models. Notably, the hyper-random tree classifier employed in this model outperforms other machine learning classifiers.

CONCLUSION

Thus, CDA-DGRL stands as a promising methodology for reliably identifying circRNA-disease associations, offering potential avenues to alleviate the necessity for extensive traditional biological experiments. The source code and data for this study are available at https://github.com/zywait/CDA-DGRL .

The potential of phosphorylated α-synuclein as a biomarker for the diagnosis and monitoring of multiple system atrophy

INTRODUCTION

Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disorder characterized by the presence of glial cytoplasmic inclusions (GCIs) containing aggregated α-synuclein (α-Syn). Accurate diagnosis and monitoring of MSA present significant challenges, which can lead to potential misdiagnosis and inappropriate treatment. Biomarkers play a crucial role in improving the accuracy of MSA diagnosis, and phosphorylated α-synuclein (p-syn) has emerged as a promising biomarker for aiding in diagnosis and disease monitoring.

METHODS

A literature search was conducted on PubMed, Scopus, and Google Scholar using specific keywords and MeSH terms without imposing a time limit. Inclusion criteria comprised various study designs including experimental studies, case-control studies, and cohort studies published only in English, while conference abstracts and unpublished sources were excluded.

RESULTS

Increased levels of p-syn have been observed in various samples from MSA patients, such as red blood cells, cerebrospinal fluid, oral mucosal cells, skin, and colon biopsies, highlighting their diagnostic potential. The α-Syn RT-QuIC assay has shown sensitivity in diagnosing MSA and tracking its progression. Meta-analyses and multicenter investigations have confirmed the diagnostic value of p-syn in cerebrospinal fluid, demonstrating high specificity and sensitivity in distinguishing MSA from other neurodegenerative diseases. Moreover, combining p-syn with other biomarkers has further improved the diagnostic accuracy of MSA.

CONCLUSION

The p-syn stands out as a promising biomarker for MSA. It is found in oligodendrocytes and shows a correlation with disease severity and progression. However, further research and validation studies are necessary to establish p-syn as a reliable biomarker for MSA. If proven, p-syn could significantly contribute to early diagnosis, disease monitoring, and assessing treatment response.

Corneal confocal microscopy may help to distinguish Multiple System Atrophy from Parkinson's disease

Multiple system atrophy (MSA) and Parkinson's disease (PD) have clinical overlapping symptoms, which makes differential diagnosis difficult. Our research aimed to distinguish MSA from PD using corneal confocal microscopy (CCM), a noninvasive and objective test. The study included 63 PD patients, 30 MSA patients, and 31 healthy controls (HC). When recruiting PD and MSA, questionnaires were conducted on motor and non-motor functions, such as autonomic and cognitive functions. Participants underwent CCM to quantify the corneal nerve fibers. Corneal nerve fiber density (CNFD) and corneal nerve fiber length (CNFL) values in MSA are lower than PD (MSA vs. PD: CNFD, 20.68 ± 6.70 vs. 24.64 ± 6.43 no./mm2, p < 0.05; CNFL, 12.01 ± 3.25 vs. 14.17 ± 3.52 no./mm2, p < 0.05). In MSA + PD (combined), there is a negative correlation between CNFD and the Orthostatic Grading Scale (OGS) (r = -0.284, p = 0.007). Similarly, CNFD in the only MSA group was negatively correlated with the Unified Multiple System Atrophy Rating Scale I and II (r = -0.391, p = 0.044; r = -0.382, p = 0.049). CNFD and CNFL were inversely associated with MSA (CNFD: β = -0.071; OR, 0.932; 95% CI, 0.872 ~ 0.996; p = 0.038; CNFL: β = -0.135; OR, 0.874; 95% CI, 0.768-0.994; p = 0.040). Furthermore, we found the area under the receiver operating characteristic curve (ROC) of CNFL was the largest, 72.01%. The CCM could be an objective and sensitive biomarker to distinguish MSA from PD. It visually reflects a more severe degeneration in MSA compared to PD.

Smooth Pursuit and Reflexive Saccade in Discriminating Multiple-System Atrophy With Predominant Parkinsonism From Parkinson's Disease

BACKGROUND AND PURPOSE

Performing the differential diagnosis of Parkinson's disease (PD) and multiple-system atrophy of parkinsonian type (MSA-P) is challenging. The oculomotor performances of patients with PD and MSA-P were investigated to explore their potential role as a biomarker for this differentiation.

METHODS

Reflexive saccades and smooth pursuit were examined in 56 patients with PD and 34 with MSA-P in the off-medication state.

RESULTS

Patients with PD and MSA-P had similar oculomotor abnormalities of prolonged and hypometric reflexive saccades. The incidence rates of decreased reflexive saccadic velocity and saccadic smooth pursuit were significantly higher in MSA-P than in PD (p<0.05 for both). Multiple logistic regression analysis indicated that slowed reflexive saccades (odds ratio [OR]=8.14, 95% confidence interval [CI]=1.45-45.5) and saccadic smooth pursuit (OR=5.27, 95% CI=1.24-22.43) were significantly related to MSA-P.

CONCLUSIONS

The distinctive oculomotor abnormalities of saccadic smooth pursuit and slowed reflexive saccades in MSA-P may serve as useful biomarkers for discriminating MSA-P from PD.

3D-CAM: a novel context-aware feature extraction framework for neurological disease classification

In clinical practice and research, the classification and diagnosis of neurological diseases such as Parkinson's Disease (PD) and Multiple System Atrophy (MSA) have long posed a significant challenge. Currently, deep learning, as a cutting-edge technology, has demonstrated immense potential in computer-aided diagnosis of PD and MSA. However, existing methods rely heavily on manually selecting key feature slices and segmenting regions of interest. This not only increases subjectivity and complexity in the classification process but also limits the model's comprehensive analysis of global data features. To address this issue, this paper proposes a novel 3D context-aware modeling framework, named 3D-CAM. It considers 3D contextual information based on an attention mechanism. The framework, utilizing a 2D slicing-based strategy, innovatively integrates a Contextual Information Module and a Location Filtering Module. The Contextual Information Module can be applied to feature maps at any layer, effectively combining features from adjacent slices and utilizing an attention mechanism to focus on crucial features. The Location Filtering Module, on the other hand, is employed in the post-processing phase to filter significant slice segments of classification features. By employing this method in the fully automated classification of PD and MSA, an accuracy of 85.71%, a recall rate of 86.36%, and a precision of 90.48% were achieved. These results not only demonstrates potential for clinical applications, but also provides a novel perspective for medical image diagnosis, thereby offering robust support for accurate diagnosis of neurological diseases.

Coenzyme Q10: A Biomarker in the Differential Diagnosis of Parkinsonian Syndromes

Multiple system atrophy (MSA) is generally a sporadic neurodegenerative disease which ranks among atypical Parkinson's syndromes. The main clinical manifestation is a combination of autonomic dysfunction and parkinsonism and/or cerebellar disability. The disease may resemble other Parkinsonian syndromes, such as Parkinson's disease (PD) or progressive supranuclear palsy (PSP), from which MSA could be hardly distinguishable during the first years of progression. Due to the lack of a reliable and easily accessible biomarker, the diagnosis is still based primarily on the clinical picture. Recently, reduced levels of coenzyme Q10 (CoQ10) were described in MSA in various tissues, including the central nervous system. The aim of our study was to verify whether the level of CoQ10 in plasma and lymphocytes could serve as an easily available diagnostic biomarker of MSA. The study reported significantly lower levels of CoQ10 in the lymphocytes of patients with MSA compared to patients with PD and controls. The reduction in CoQ10 levels in lymphocytes correlated with the increasing degree of clinical involvement of patients with MSA. CoQ10 levels in lymphocytes seem to be a potential biomarker of disease progression.

α-Synuclein seed amplification assay as a diagnostic tool for parkinsonian disorders

INTRODUCTION

Synucleinopathies such as Parkinson's disease (PD) and multiple system atrophy (MSA) can be challenging to diagnose due to the symptom overlap with, for example, atypical parkinsonisms like progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Seed amplification assays (SAA), developed for the detection of α-synuclein (αSyn) aggregates in CSF, have been successful when used as a biomarker evaluation for synucleinopathies. In this study, we investigated the potential of this assay to not only detect αSyn seeds in CSF, but also discriminate between movement disorders.

METHODS

The αSyn-SAA was tested in a Scandinavian cohort composed of 129 CSF samples from patients with PD (n = 55), MSA (n = 27), CBD (n = 7), and PSP (n = 16), as well as healthy controls (HC, n = 24).

RESULTS

The αSyn seed amplification assay (αSyn-SAA) was able to correctly identify all PD samples as positive (sensitivity of 100%) while also discriminating the PD group from HC (70.8% specificity, p < 0.0001) and tauopathies [CBD (71% specificity) and PSP (75% specificity), p < 0.0001)]. The αSyn-SAA was also able to identify almost all MSA samples as positive for αSyn aggregation (sensitivity of 92.6%). In general, this assay is able to discriminate between the synucleinopathies and tauopathies analyzed herein (p < 0.0001) despite the overlapping symptoms in these diseases.

CONCLUSION

These findings suggest the αSyn-SAA is a useful diagnostic tool for differentiating between different parkinsonian disorders, although further optimization may be needed.

Effects of Rehabilitative Intervention for Augmenting Cough Function in Patients with Multiple System Atrophy

Objectives

One of the causes of death in patients with multiple system atrophy (MSA) is aspiration pneumonia caused by cough dysfunction. This study aimed to identify an effective approach to improve coughing and to explore the establishment of criteria for the use of gastrostomy based on cough and respiratory dysfunctions.

Methods

Eighteen probable MSA patients participated in the study. They were categorized into air stacking and non-air stacking groups. First, we investigated how the inspiration volume changes by applying maximum insufflation capacity (MIC). Second, peak cough flow (PCF) was measured by different cough augmentation methods: 1) spontaneous coughing (SpC); 2) SpC with MIC (SpC + MIC); 3) SpC with manually assisted cough (MAC) (SpC + MAC); and 4) SpC with MIC and MAC (SpC + MIC + MAC). Among these four conditions, PCF values were compared to determine the most effective approach for cough augmentation. Receiver operating characteristic analysis was performed on percent forced vital capacity (%FVC) to determine an index for discriminating PCF below160 L/min, which indicates a high risk of suffocation, involving SpC and SpC + MIC.

Results

Inspiration volume increased significantly with MIC in both groups (P < 0.05), and PCF increased significantly with MIC in the air stacking group (P < 0.01). PCF could not be maintained at 160 L/min when %FVC fell below 59%, even when MIC was applied.

Conclusions

PCF increases with MIC in patients with MSA. It may be meaningful to consider the timing of gastrostomy introduction based on the severity of cough and respiratory dysfunction.

Diagnosing multiple system atrophy: current clinical guidance and emerging molecular biomarkers

Multiple system atrophy (MSA) is a rare and progressive neurodegenerative disorder characterized by motor and autonomic dysfunction. Accurate and early diagnosis of MSA is challenging due to its clinical similarity with other neurodegenerative disorders, such as Parkinson's disease and atypical parkinsonian disorders. Currently, MSA diagnosis is based on clinical criteria drawing from the patient's symptoms, lack of response to levodopa therapy, neuroimaging studies, and exclusion of other diseases. However, these methods have limitations in sensitivity and specificity. Recent advances in molecular biomarker research, such as α-synuclein protein amplification assays (RT-QuIC) and other biomarkers in cerebrospinal fluid and blood, have shown promise in improving the diagnosis of MSA. Additionally, these biomarkers could also serve as targets for developing disease-modifying therapies and monitoring treatment response. In this review, we provide an overview of the clinical syndrome of MSA and discuss the current diagnostic criteria, limitations of current diagnostic methods, and emerging molecular biomarkers that offer hope for improving the accuracy and early detection of MSA.

Prediction of type 1 diabetes with machine learning algorithms based on FTIR spectral data in peripheral blood mononuclear cells

The incidence of autoimmunity is increasing, to ensure timely and comprehensive treatment, there must be a diagnostic method or markers that would be available to the general public. Fourier-transform infrared spectroscopy (FTIR) is a relatively inexpensive and accurate method for determining metabolic fingerprint. The metabolism, molecular composition and function of blood cells vary according to individual physiological and pathological conditions. Thus, by obtaining autoimmune disease-specific metabolic fingerprint markers in peripheral blood mononuclear cells (PBMC) and subsequently using machine learning algorithms, it might be possible to create a tool that will allow the diagnosis of autoimmune diseases. In this preliminary study, it was found that the peak shift at 1545 cm-1 could be considered specific for autoimmune disease type 1 diabetes (T1D), while the shifts at 1070 and 1417 cm-1 could be more attributed to the autoimmune condition per se. The prediction of T1D, despite the small number of participants in the study, showed an inverse AUC = 0.33 ± 0.096, n = 15, indicating a stable trend in the prediction of T1D based on FTIR metabolic fingerprint data in the PBMC.

Sleep Disorders Associated with Neurodegenerative Diseases

Sleep disturbances are common in various neurological pathologies, including amyotrophic lateral sclerosis (ALS), multiple system atrophy (MSA), hereditary ataxias, Huntington's disease (HD), progressive supranuclear palsy (PSP), and dementia with Lewy bodies (DLB). This article reviews the prevalence and characteristics of sleep disorders in these conditions, highlighting their impact on patients' quality of life and disease progression. Sleep-related breathing disorders, insomnia, restless legs syndrome (RLS), periodic limb movement syndrome (PLMS), and rapid eye movement sleep behavior disorder (RBD) are among the common sleep disturbances reported. Both pharmacological and non-pharmacological interventions play crucial roles in managing sleep disturbances and enhancing overall patient care.

Primary lateral sclerosis plus parkinsonism: a case report

BACKGROUND

The standard of diagnosing primary lateral sclerosis, the Pringle criteria, requires three years of purely upper motor neuron symptom presentation before confirming diagnosis. This classic standard has been questioned on occasion due to its restrictive range of both time period and symptomatic exhibition.

CASE PRESENTATION

This case report will review a 57-year-old Caucasian female who presented with pyramidal and extrapyramidal features suggestive of the exceedingly rare disease primary lateral sclerosis plus parkinsonism. We will describe the mixture of upper motor neuron signs and striking parkinsonian symptoms experienced by the patient, as well as the full diagnostic workup leading to her preliminary diagnosis. The details of this case will then be utilized to explore the diagnostic criteria of primary lateral sclerosis, as well as to work through the differential of conditions resembling Parkinson's disease.

CONCLUSIONS

The current criteria to diagnose primary lateral sclerosis may be excluding patients with the disease and is an ongoing area of investigation. A thorough differential including other neurodegenerative conditions is necessary to consider and requires long-term follow-up.

α-Synuclein-carrying astrocytic extracellular vesicles in Parkinson pathogenesis and diagnosis

BACKGROUND

The accumulation of α-synuclein (α-syn), an essential step in PD development and progression, is observed not only in neurons but also in glia, including astrocytes. The mechanisms regulating astrocytic α-syn level and aggregation remain unclear. More recently, it has been demonstrated that a part of α-syn spreading occurs through extracellular vesicles (EVs), although it is unknown whether this process is involved in astrocytes of PD. It is known, however, that EVs derived from the central nervous system exist in the blood and are extensively explored as biomarkers for PD and other neurodegenerative disorders.

METHODS

Primary astrocytes were transfected with A53T α-syn plasmid or exposed to α-syn aggregates. The level of astrocyte-derived EVs (AEVs) was assessed by nanoparticle tracking analysis and immunofluorescence. The lysosomal function was evaluated by Cathepsin assays, immunofluorescence for levels of Lamp1 and Lamp2, and LysoTracker Red staining. The Apogee assays were optimized to measure the GLT-1+ AEVs in clinical cohorts of 106 PD, 47 multiple system atrophy (MSA), and 103 healthy control (HC) to test the potential of plasma AEVs as a biomarker to differentiate PD from other forms of parkinsonism.

RESULTS

The number of AEVs significantly increased in primary astrocytes with α-syn deposition. The mechanism of increased AEVs was partially attributed to lysosomal dysfunction. The number of α-syn-carrying AEVs was significantly higher in patients with PD than in HC and MSA. The integrative model combining AEVs with total and aggregated α-syn exhibited efficient diagnostic power in differentiating PD from HC with an AUC of 0.915, and from MSA with an AUC of 0.877.

CONCLUSIONS

Pathological α-syn deposition could increase the astrocytic secretion of EVs, possibly through α-syn-induced lysosomal dysfunction. The α-syn-containing AEVs in the peripheral blood may be an effective biomarker for clinical diagnosis or differential diagnosis of PD.

Urinary tract infections trigger synucleinopathy via the innate immune response

Symptoms in the urogenital organs are common in multiple system atrophy (MSA), also in the years preceding the MSA diagnosis. It is unknown how MSA is triggered and these observations in prodromal MSA led us to hypothesize that synucleinopathy could be triggered by infection of the genitourinary tract causing ɑ-synuclein (ɑSyn) to aggregate in peripheral nerves innervating these organs. As a first proof that peripheral infections could act as a trigger in MSA, this study focused on lower urinary tract infections (UTIs), given the relevance and high frequency of UTIs in prodromal MSA, although other types of infection might also be important triggers of MSA. We performed an epidemiological nested-case control study in the Danish population showing that UTIs are associated with future diagnosis of MSA several years after infection and that it impacts risk in both men and women. Bacterial infection of the urinary bladder triggers synucleinopathy in mice and we propose a novel role of ɑSyn in the innate immune system response to bacteria. Urinary tract infection with uropathogenic E. coli results in the de novo aggregation of ɑSyn during neutrophil infiltration. During the infection, ɑSyn is released extracellularly from neutrophils as part of their extracellular traps. Injection of MSA aggregates into the urinary bladder leads to motor deficits and propagation of ɑSyn pathology to the central nervous system in mice overexpressing oligodendroglial ɑSyn. Repeated UTIs lead to progressive development of synucleinopathy with oligodendroglial involvement in vivo. Our results link bacterial infections with synucleinopathy and show that a host response to environmental triggers can result in ɑSyn pathology that bears semblance to MSA.

Dealing with the heterogeneous presentations of freezing of gait: how reliable are the freezing index and heart rate for freezing detection?

BACKGROUND

Freezing of gait (FOG) is an unpredictable gait arrest that hampers the lives of 40% of people with Parkinson's disease. Because the symptom is heterogeneous in phenotypical presentation (it can present as trembling/shuffling, or akinesia) and manifests during various circumstances (it can be triggered by e.g. turning, passing doors, and dual-tasking), it is particularly difficult to detect with motion sensors. The freezing index (FI) is one of the most frequently used accelerometer-based methods for FOG detection. However, it might not adequately distinguish FOG from voluntary stops, certainly for the akinetic type of FOG. Interestingly, a previous study showed that heart rate signals could distinguish FOG from stopping and turning movements. This study aimed to investigate for which phenotypes and evoking circumstances the FI and heart rate might provide reliable signals for FOG detection.

METHODS

Sixteen people with Parkinson's disease and daily freezing completed a gait trajectory designed to provoke FOG including turns, narrow passages, starting, and stopping, with and without a cognitive or motor dual-task. We compared the FI and heart rate of 378 FOG events to baseline levels, and to stopping and normal gait events (i.e. turns and narrow passages without FOG) using mixed-effects models. We specifically evaluated the influence of different types of FOG (trembling vs akinesia) and triggering situations (turning vs narrow passages; no dual-task vs cognitive dual-task vs motor dual-task) on both outcome measures.

RESULTS

The FI increased significantly during trembling and akinetic FOG, but increased similarly during stopping and was therefore not significantly different from FOG. In contrast, heart rate change during FOG was for all types and during all triggering situations statistically different from stopping, but not from normal gait events.

CONCLUSION

When the power in the locomotion band (0.5-3 Hz) decreases, the FI increases and is unable to specify whether a stop is voluntary or involuntary (i.e. trembling or akinetic FOG). In contrast, the heart rate can reveal whether there is the intention to move, thus distinguishing FOG from stopping. We suggest that the combination of a motion sensor and a heart rate monitor may be promising for future FOG detection.

Functional connectome automatically differentiates multiple system atrophy (parkinsonian type) from idiopathic Parkinson's disease at early stages

Differentiating the parkinsonian variant of multiple system atrophy (MSA-P) from idiopathic Parkinson's disease (IPD) is challenging, especially in the early stages. This study aimed to investigate differences and similarities in the brain functional connectomes of IPD and MSA-P patients and use machine learning methods to explore the diagnostic utility of these features. Resting-state fMRI data were acquired from 88 healthy controls, 76 MSA-P patients, and 53 IPD patients using a 3.0 T scanner. The whole-brain functional connectome was constructed by thresholding the Pearson correlation matrices of 116 regions, and topological properties were evaluated through graph theory approaches. Connectome measurements were used as features in machine learning models (random forest [RF]/logistic regression [LR]/support vector machine) to distinguish IPD and MSA-P patients. Regarding graph metrics, early IPD and MSA-P patients shared network topological properties. Both patient groups showed functional connectivity disruptions within the cerebellum-basal ganglia-cortical network, but these disconnections were mainly in the cortico-thalamo-cerebellar circuits in MSA-P patients and the basal ganglia-thalamo-cortical circuits in IPD patients. Among the connectome parameters, t tests combined with the RF method identified 15 features, from which the LR classifier achieved the best diagnostic performance on the validation set (accuracy = 92.31%, sensitivity = 90.91%, specificity = 93.33%, area under the receiver operating characteristic curve = 0.89). MSA-P and IPD patients show similar whole-brain network topological alterations. MSA-P primarily affects cerebellar nodes, and IPD primarily affects basal ganglia nodes; both conditions disrupt the cerebellum-basal ganglia-cortical network. Moreover, functional connectome parameters showed outstanding value in the differential diagnosis of early MSA-P and IPD.

microRNA and circRNA in Parkinson's Disease and atypical parkinsonian syndromes

Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP) are atypical parkinsonian syndromes (APS) with various clinical phenotypes and considerable clinical overlap with idiopathic Parkinson's disease (iPD). This disease heterogeneity makes ante-mortem diagnosis extremely challenging with up to 24% of patients misdiagnosed. Because diagnosis is predominantly clinical, there is great interest in identifying biomarkers for early diagnosis and differentiation of the different types of parkinsonism. Compared to protein biomarkers, microRNAs (miRNAs) and circularRNAs (circRNAs) are stable tissue-specific molecules that can be accurately measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). This chapter critically reviews miRNAs and circRNAs as diagnostic biomarkers and therapeutics to differentiate atypical parkinsonian disorders and their role in disease pathogenesis.

Genetics of Multiple System Atrophy and Progressive Supranuclear Palsy: A Systemized Review of the Literature

Multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) are uncommon multifactorial atypical Parkinsonian syndromes, expressed by various clinical features. MSA and PSP are commonly considered sporadic neurodegenerative disorders; however, our understanding is improving of their genetic framework. The purpose of this study was to critically review the genetics of MSA and PSP and their involvement in the pathogenesis. A systemized literature search of PubMed and MEDLINE was performed up to 1 January 2023. Narrative synthesis of the results was undertaken. In total, 43 studies were analyzed. Although familial MSA cases have been reported, the hereditary nature could not be demonstrated. COQ2 mutations were involved in familial and sporadic MSA, without being reproduced in various clinical populations. In terms of the genetics of the cohort, synuclein alpha (SNCA) polymorphisms were correlated with an elevated likelihood of manifesting MSA in Caucasians, but a causal effect relationship could not be demonstrated. Fifteen MAPT mutations were linked with PSP. Leucine-rich repeat kinase 2 (LRRK2) is an infrequent monogenic mutation of PSP. Dynactin subunit 1 (DCTN1) mutations may imitate the PSP phenotype. GWAS have noted many risk loci of PSP (STX6 and EIF2AK3), suggesting pathogenetic mechanisms related to PSP. Despite the limited evidence, it seems that genetics influence the susceptibility to MSA and PSP. MAPT mutations result in the MSA and PSP pathologies. Further studies are crucial to elucidate the pathogeneses of MSA and PSP, which will support efforts to develop novel drug options.

Value of electrophysiological indicators in differential diagnosis of parkinson's disease and multiple system atrophy

BACKGROUND

We evaluated the value of electrophysiological indicators by external anal sphincter electromyography (EAS-EMG), sympathetic skin response (SSR), R-R interval variation (RRIV), and Bulbocavernosus Reflex (BCR) in differential diagnosis of multiple system atrophy (MSA) and Parkinson's disease (PD).

METHODS

A total of 41 patients with MSA and 32 patients with PD were enrolled. The electrophysiological changes of autonomic dysfunction were assessed with BCR, EAS-EMG, SSR, and RRIV, and the abnormal rate of each indicator was calculated. The diagnostic value of each indicator was analyzed with ROC curve.

RESULTS

The incidence rate of autonomic dysfunction in MSA group was significantly higher than that in PD group (p < 0.05). The abnormal rates of BCR and EAS-EMG indicators in MSA group were higher than those in PD group (p < 0.05). The abnormal rates of SSR and RRIV indicators in MSA group and PD group were high; however, there was no significant difference between MSA and PD groups (p > 0.05). The sensitivity of BCR combined with EAS-EMG indicators in differential diagnosis of MSA and PD were 92.3% in males and 86.7% in females, respectively, and the specificity was 72.7% in males and 90% in females, respectively.

CONCLUSIONS

Combined analysis of BCR and EAS-EMG has high sensitivity and specificity for differential diagnosis of MSA and PD.

The characteristic of nonmotor symptoms with different phenotypes and onsets in multiple system atrophy patients

OBJECTIVES

The characteristic of nonmotor symptoms in patients with multiple system atrophy (MSA) has varied among previous studies. The objective was to investigatethe nonmotor characteristics in MSA patients with different phenotypes, sex and different onset patterns.

METHODS

We performed a retrospective review of 1492 MSA patients. All cases were evaluatedby neurologists and assessed with motormanifestations, nonmotor symptoms, auxiliary examinationand brain MRI scans.

RESULTS

Multiple system atrophy-cerebellar ataxia (MSA-C) was the predominant phenotype in 998 patients. Average age of onset (56.8 ± 9.2 years) was earlier, the disease duration (2.4 ± 2.2 year) was shorter and brain MRI abnormalities (49.2 %) were more frequently in MSA-C (P < 0.001). Multiple system atrophy-parkinsonism (MSA-P) patients were more likely to have nonmotor symptoms. After adjusted significant parameters, urinary dysfunction (OR 1.441, 95 %CI = 1.067-1.946, P = 0.017), constipation (OR 1.482, 95 %CI = 1.113-1.973, P = 0.007), cognitive impairment (OR 1.509, 95 %CI = 1.074-2.121, P = 0.018) and drooling (OR 2.095, 95 %CI = 1.248-3.518, P = 0.005) were associated with the MSA-P phenotype. Males were more likely to have orthostatic hypotension, urinary dysfunction, sexual dysfunction, drooling and females in constipation and probable RBD. In different onset patterns, constipation (59.2 %) and probable RBD (28.4 %) were more frequently in autonomiconset pattern.

CONCLUSIONS

MSA-C is the predominant phenotype in Chinese patients, while many nonmotor symptoms are more common in MSA-P phenotype. Patients with different sex and onset patterns have different nonmotor characteristics. The different clinical features identified could help the physician counseling of MSA patients more easily and more accurately.

[Multiple system atrophy]

The article presents a progressive neurodegenerative disease - multisystem atrophy, characterized by a combination of autonomic failure and various motor disorders, including parkinsonism and/or cerebellar ataxia; etiopathogenetic factors and variants of the clinical picture are described. We describe own clinical observation of a 59-old patient with cerebellar and bulbar syndromes, parkinsonism, pyramidal insufficiency, cognitive deficits, and autonomic dysfunction. The differential diagnosis included a whole range of neurodegenerative and hereditary diseases: Parkinson's disease, vascular parkinsonism, progressive supranuclear palsy, spinocerebellar ataxia, FXTAS, mitochondrial encephalopathies. The moderate severity of parkinsonism and the significant predominance of cerebellar symptoms and autonomic dysfunction make this clinical case difficult to diagnose. However, based on the life and disease history, clinical picture and research methods, a diagnosis of multiple system atrophy, cerebellar type (cerebellar, autonomic, bulbar syndrome, parkinsonism, pyramidal insufficiency and moderate cognitive impairment) was established. Differential search in such patients is a difficult task and includes a whole range of neurodegenerative and hereditary diseases due to the similarity of individual clinical and neuroimaging features and, unfortunately, the limited availability of molecular genetic diagnostic methods. However, earlier diagnosis is necessary to focus in time on the development of a personalized approach to the management of each such patient, taking into account the rate of symptoms development and steady progression, in order to ensure the longest possible survival time with an acceptable level of quality of life.

Exploring the mechanism of astragalus membranaceus in the treatment of multiple system atrophy based on network pharmacology and molecular docking

Multiple system atrophy (MSA) is a fatal neurodegenerative disease, it causes functional degradation of multiple organs and systems throughout the body. Astragalus membranaceus (AM), a well-known traditional Chinese medicine, has been used to improve muscle wasting-related disorders for a long history. In this study, we used network pharmacology and molecular docking to predict the mechanism underlying AM for the treatment of MSA. We screened the active compounds of AM and its related targets, as well as the target proteins of MSA. We made a Venn diagram to obtain the intersecting targets and then constructed a protein-protein interaction network to find the core targets and build an active ingredient-target network map. After subjecting the intersecting targets to gene ontology and Kyoto encyclopedia of genes and genomes analysis, the binding ability of core compounds and core target proteins were validated by molecular docking. A total of 20 eligible compounds and 274 intersecting targets were obtained. The core components of treatment are quercetin, kaempferol, and isorhamnetin, and the core targets are TP53, RELA, and TNF. The main biological processes are related to cellular responses and regulation. Molecular functions are mainly associated with apoptosis, inflammation, and tumorigenesis. Molecular docking results show good and standard binding abilities. This study illustrates that AM treats MSA through multiple targets and pathways, and provides a reference for subsequent research.

Host oligodendrogliopathy and α-synuclein strains dictate disease severity in multiple system atrophy

Multiple system atrophy is a progressive neurodegenerative disease with prominent autonomic and motor features. During early stages, different subtypes of the disease are distinguished by their predominant parkinsonian or cerebellar symptoms, reflecting its heterogeneous nature. The pathognomonic feature of multiple system atrophy is the presence of α-synuclein (αSyn) protein deposits in oligodendroglial cells. αSyn can assemble in specific cellular or disease environments and form αSyn strains with unique structural features, but the ability of αSyn strains to propagate in oligodendrocytes remains elusive. Recently, it was shown that αSyn strains with related conformations exist in the brains of patients. Here, we investigated whether different αSyn strains can influence multiple system atrophy progression in a strain-dependent manner. To this aim, we injected two recombinant αSyn strains (fibrils and ribbons) in multiple system atrophy transgenic mice and found that they determined disease severity in multiple system atrophy via host-restricted and cell-specific pathology in vivo. αSyn strains significantly impact disease progression in a strain-dependent way via oligodendroglial, neurotoxic and immune-related mechanisms. Neurodegeneration and brain atrophy were accompanied by unique microglial and astroglial responses and the recruitment of central and peripheral immune cells. The differential activation of microglial cells correlated with the structural features of αSyn strains both in vitro and in vivo. Spectral analysis showed that ribbons propagated oligodendroglial inclusions that were structurally distinct from those of fibrils, with resemblance to oligodendroglial inclusions, in the brains of patients with multiple system atrophy. This study, therefore, shows that the multiple system atrophy phenotype is governed by both the nature of the αSyn strain and the host environment and that by injecting αSyn strains into an animal model of the disease, a more comprehensive phenotype can be established.

Parkinson disease primer, part 1: diagnosis

OBJECTIVE

To provide family physicians an updated approach to the diagnosis of Parkinson disease (PD).

SOURCES OF INFORMATION

Published guidelines on the diagnosis and management of PD were reviewed. Database searches were conducted to retrieve relevant research articles published between 2011 and 2021. Evidence levels ranged from I to III.

MAIN MESSAGE

Diagnosis of PD is predominantly clinical. Family physicians should evaluate patients for specific features of parkinsonism, then determine whether symptoms are attributable to PD. Levodopa trials can be used to help confirm the diagnosis and alleviate motor symptoms of PD. "Red flag" features and absence of response to levodopa may point to other causes of parkinsonism and prompt more urgent referral.

CONCLUSION

Access to neurologists and specialized clinics varies, and Canadian family physicians can be important players in facilitating early and accurate diagnosis of PD. Applying an organized approach to diagnosis and considering motor and nonmotor symptoms can greatly benefit patients with PD. Part 2 in this series will review management of PD.

Comparison of the second consensus statement with the movement disorder society criteria for multiple system atrophy: A single-center analysis

INTRODUCTION

This study aimed at comparing the differences between the second consensus statement and Movement Disorder Society (MDS) criteria for Multiple System Atrophy (MSA) in a single Chinese cohort.

METHODS

We retrospectively reviewed 73 patients with MSA over the past five years. They were categorized as patients with probable and possible MSA according to the second consensus statement in addition to clinically established and clinically probable MSA according to the MDS criteria. The core clinical, supportive clinical, and imaging features were analyzed and compared between the two MSA subtypes.

RESULTS

A total of 40 patients with MSA-P and 33 patients with MSA-C were included in this study. Approximately 78.7% of the category of probable patients in the second consensus statement can be categorized as clinically established MSA in the MDS criteria and five patients with non-supporting features in the second consensus statement criteria can be diagnosed as clinically probable MSA in the MDS criteria. "Rapid progression" and "moderate to severe postural instability" within three years of motor onset dominated among the supportive features. Approximately 78.9% of patients possessed at least one imaging marker with predominant signal decrease of putamen on iron-sensitive sequences (38.0% of patients). Twenty-two patients could not be diagnosed as clinically established MSA mainly due to the lack of supportive or imaging features.

CONCLUSIONS

A high degree of agreement was noticed between the two criteria sets. The supportive and imaging features played important role in the diagnosis of MSA and affected the diagnostic level in the current criteria.

Abécédaire de la maladie de Parkinson, partie 1 : le diagnostic

Objectif

Présenter aux médecins de famille une approche actualisée du diagnostic de la maladie de Parkinson (MP).

Sources de l’information

Les lignes directrices sur le diagnostic et la prise en charge de la MP ont été passées en revue. Des recensions dans les bases de données ont été effectuées pour en extraire les articles de recherche publiés entre 2011 et 2021. Le niveau des données probantes varie entre I et III.

Message principal

Le diagnostic de la MP est principalement d’ordre clinique. Les médecins de famille devraient évaluer les patients en fonction des caractéristiques particulières du parkinsonisme et déterminer ensuite si les symptômes sont attribuables à la MP. Des essais à la lévodopa peuvent servir à confirmer le diagnostic et à atténuer les symptômes moteurs de la MP. Des « signaux d’alerte » et l’absence de réponse à la lévodopa pourraient indiquer d’autres causes du parkinsonisme et inciter à faire une demande de consultation plus urgente.

Conclusion

L’accès à des neurologues et à des cliniques spécialisées est variable, et les médecins de famille canadiens peuvent être des acteurs importants pour faciliter un diagnostic précoce et exact de la MP. La mise en application d’une approche structurée du diagnostic, et la prise en compte des symptômes moteurs et non moteurs peuvent être grandement bénéfiques pour les patients atteints de la MP. La partie 2 de cette série portera sur la prise en charge de la MP.

Synucleinopathies

The α-synucleinopathies include pure autonomic failure, multiple system atrophy, dementia with Lewy bodies, and Parkinson disease. The past two decades have witnessed significant advances in the diagnostic strategies and symptomatic treatment of motor and nonmotor symptoms of the synucleinopathies. This chapter provides an in-depth review of the pathophysiology, pathology, genetic, epidemiology, and clinical and laboratory autonomic features that distinguish the different synucleinopathies with an emphasis on autonomic failure as a common feature. The treatment of the different synucleinopathies is discussed along with the proposal for multidisciplinary, individualized care models that optimally address the various symptoms. There is an urgent need for clinical scientific studies addressing patients at risk of developing synucleinopathies and the investigation of disease mechanisms, biomarkers, potential disease-modifying therapies, and further advancement of symptomatic treatments for motor and nonmotor symptoms.

Aggregated Alpha-Synuclein Inclusions within the Nucleus Predict Impending Neuronal Cell Death in a Mouse Model of Parkinsonism

Alpha-synuclein (aSyn) is a 14 kD protein encoded by the SNCA gene that is expressed in vertebrates and normally localizes to presynaptic terminals and the nucleus. aSyn forms pathological intracellular aggregates that typify a group of important neurodegenerative diseases called synucleinopathies. Previous work in human tissue and model systems indicates that some of these aggregates can be intranuclear, but the significance of aSyn aggregation within the nucleus is not clear. We used a mouse model that develops aggregated aSyn nuclear inclusions. Using aSyn preformed fibril injections in GFP-tagged aSyn transgenic mice, we were able to induce the formation of nuclear aSyn inclusions and study their properties in fixed tissue and in vivo using multiphoton microscopy. In addition, we analyzed human synucleinopathy patient tissue to better understand this pathology. Our data demonstrate that nuclear aSyn inclusions may form through the transmission of aSyn between neurons, and these intranuclear aggregates bear the hallmarks of cytoplasmic Lewy pathology. Neuronal nuclear aSyn inclusions can form rod-like structures that do not contain actin, excluding them from being previously described nuclear actin rods. Longitudinal, in vivo multiphoton imaging indicates that certain morphologies of neuronal nuclear aSyn inclusions predict cell death within 14 days. Human multiple system atrophy cases contain neurons and glia with similar nuclear inclusions, but we were unable to detect such inclusions in Lewy body dementia cases. This study suggests that the dysregulation of a nuclear aSyn function associated with nuclear inclusion formation could play a role in the forms of neurodegeneration associated with synucleinopathy.

Clinical outcomes and cognitive impairments between progressive supranuclear palsy and multiple system atrophy

BACKGROUND

Both progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) belong to atypical parkinsonian syndromes. It is important to differentiate these diseases accurately. We compared clinical outcomes and cognitive impairments between PSP and MSA.

METHODS

Eighty-five MSA parkinsonism type (MSA-P) patients and 76 PSP patients participated in this research. The Montreal Cognitive Assessment (MoCA) and the mini-mental state examination (MMSE) evaluated cognitive function.

RESULTS

MSA-P patients had a significantly higher incidence of dyskinesia, fall, urinary symptoms, and constipation, whereas patients with PSP had a higher incidence of tremor and salivation. MSA-P patients had higher MMSE and MoCA scores than PSP patients. The MMSE score showed a diagnostic cut-off score of 24.5 in PSP versus MSA-P. The MoCA score showed a diagnostic cut-off score of 20.5 in PSP versus MSA-P.

CONCLUSION

In conclusion, patients with PSP had differences in the clinical outcomes and cognitive impairments compared with MSA-P patients. PSP patients had more severe cognitive deficits. The score of MMSE and MoCA could be used in distinguishing MSA-P from PSP.

Glutathione Depletion and MicroRNA Dysregulation in Multiple System Atrophy: A Review

Multiple system atrophy (MSA) is a rare neurodegenerative disease characterized by parkinsonism, cerebellar impairment, and autonomic failure. Although the causes of MSA onset and progression remain uncertain, its pathogenesis may involve oxidative stress via the generation of excess reactive oxygen species and/or destruction of the antioxidant system. One of the most powerful antioxidants is glutathione, which plays essential roles as an antioxidant enzyme cofactor, cysteine-storage molecule, major redox buffer, and neuromodulator, in addition to being a key antioxidant in the central nervous system. Glutathione levels are known to be reduced in neurodegenerative diseases. In addition, genes regulating redox states have been shown to be post-transcriptionally modified by microRNA (miRNA), one of the most important types of non-coding RNA. miRNAs have been reported to be dysregulated in several diseases, including MSA. In this review, we focused on the relation between glutathione deficiency, miRNA dysregulation and oxidative stress and their close relation with MSA pathology.

Multiple system atrophy: α-Synuclein strains at the neuron-oligodendrocyte crossroad

The aberrant accumulation of α-Synuclein within oligodendrocytes is an enigmatic, pathological feature specific to Multiple system atrophy (MSA). Since the characterization of the disease in 1969, decades of research have focused on unravelling the pathogenic processes that lead to the formation of oligodendroglial cytoplasmic inclusions. The discovery of aggregated α-Synuclein (α-Syn) being the primary constituent of glial cytoplasmic inclusions has spurred several lines of research investigating the relationship between the pathogenic accumulation of the protein and oligodendrocytes. Recent developments have identified the ability of α-Syn to form conformationally distinct “strains” with varying behavioral characteristics and toxicities. Such “strains” are potentially disease-specific, providing insight into the enigmatic nature of MSA. This review discusses the evidence for MSA-specific α-Syn strains, highlighting the current methods for detecting and characterizing MSA patient-derived α-Syn. Given the differing behaviors of α-Syn strains, we explore the seeding and spreading capabilities of MSA-specific strains, postulating their influence on the aggressive nature of the disease. These ideas culminate into one key question: What causes MSA–specific strain formation? To answer this, we discuss the interplay between oligodendrocytes, neurons and α-Syn, exploring the ability of each cell type to contribute to the aggregate formation while postulating the effect of additional variables such as protein interactions, host characteristics and environmental factors. Thus, we propose the idea that MSA strain formation results from the intricate interrelation between neurons and oligodendrocytes, with deficits in each cell type required to initiate α-Syn aggregation and MSA pathogenesis.

Graphical Abstract

Case report: Combined therapy of bilateral subthalamic nucleus deep brain stimulation and spinal cord stimulation significantly improves motor function in a patient with multiple system atrophy with predominant parkinsonism

Multiple system atrophy with predominant parkinsonism (MSA-P) is a highly incapacitating disease with a short life expectancy and symptomatic therapy is still limited. In this report, we presented the case of a 65-year-old woman with a 3-year history of severe rigidity, bradykinesia, and gait dysfunction alongside severe freezing of gait diagnosed with MSA-P. She underwent combined therapy of bilateral subthalamic nucleus deep brain stimulation (DBS) and low-thoracic spinal cord stimulation (SCS). The double-blind evaluation of the Movement Disorder Society Sponsored Revision of the Unified Parkinson's Disease Rating Scale part III and 7-m Timed Up and Go at follow-ups showed her cardinal parkinsonian symptoms benefit significantly from DBS stimulation, while the improvement of SCS was mainly embodied in lower-limb symptoms. The combined stimulation achieved a better improvement of motor function than either DBS or SCS stimulation alone. Most notably, the improvement of lower-limb symptoms was significantly enhanced by the combined stimulation.

Differential diagnosis of patients with atypical Parkinsonian syndrome using 18F-FDG and 18F-FP CIT PET: A report of five cases

We describe 5 cases of patients who presented atypical parkinsonian syndrome (APS), including gait disturbance, postural instability, decreasing facial expression, dyskinesia, and subjective cognitive impairment. The patients underwent 18F-FP-CIT PET and 18F-FDG PET consecutively for differential diagnosis of APS. Through PET imaging examination, it was possible to offer a suggestive diagnosis and determine individual strategic management for patients with APS.

Alpha-Synuclein Strain Variability in Body-First and Brain-First Synucleinopathies

Pathogenic alpha-synuclein (asyn) aggregates are a defining feature of neurodegenerative synucleinopathies, which include Parkinson's disease, Lewy body dementia, pure autonomic failure and multiple system atrophy. Early accurate differentiation between these synucleinopathies is challenging due to the highly heterogeneous clinical profile at early prodromal disease stages. Therefore, diagnosis is often made in late disease stages when a patient presents with a broad range of motor and non-motor symptoms easing the differentiation. Increasing data suggest the clinical heterogeneity seen in patients is explained by the presence of distinct asyn strains, which exhibit variable morphologies and pathological functions. Recently, asyn seed amplification assays (PMCA and RT-QuIC) and conformation-specific ligand assays have made promising progress in differentiating between synucleinopathies in prodromal and advanced disease stages. Importantly, the cellular environment is known to impact strain morphology. And, asyn aggregate pathology can propagate trans-synaptically along the brain-body axis, affecting multiple organs and propagating through multiple cell types. Here, we present our hypothesis that the changing cellular environments, an asyn seed may encounter during its brain-to-body or body-to-brain propagation, may influence the structure and thereby the function of the aggregate strains developing within the different cells. Additionally, we aim to review strain characteristics of the different synucleinopathies in clinical and preclinical studies. Future preclinical animal models of synucleinopathies should investigate if asyn strain morphology is altered during brain-to-body and body-to-brain spreading using these seeding amplification and conformation-specific assays. Such findings would greatly deepen our understanding of synucleinopathies and the potential link between strain and phenotypic variability, which may enable specific diagnosis of different synucleinopathies in the prodromal phase, creating a large therapeutic window with potential future applications in clinical trials and personalized therapeutics.

The Non-motor Symptoms, Disability Progression, and Survival Analysis of Atypical Parkinsonism: Case Series from Eastern India and Brief Review of Literature

Objective The objectives of this study are (1) to describe the non-motor profile, the motor disability progression, and survival analysis of atypical parkinsonism in a tertiary care hospital of eastern India and (2) to elucidate the neurocircuitry and the putative substrates responsible for non-motor manifestations.

Methods In this prospective observational study, patients were diagnosed based on Consensus Criteria for Progressive Supranuclear Palsy (PSP), The Fourth Consensus Report of the Dementia with Lewy Body (DLBD) Consortium 2017, The Autonomic Neuroscience 2018 Criteria for Multiple System Atrophy (MSA), and Armstrong 2013 Criteria for Corticobasal Degeneration (CBD). Disease severity was assessed at baseline and 6 months of follow-up using the Unified Parkinson's Disease Rating Scales (UPDRS). For PSP and MSA, the PSP-Clinical Deficits Scale (PSP-CDS) and the Unified MSA Rating Scale (UMSARS), respectively, were used. Cox regression analysis and the hazard ratio were calculated.

Results Out of 27 patients, the diagnosis was probable PSP in 12, probable MSA in 7, probable CBD in 5, and probable DLBD in 3. Non-motor symptoms were highly prevalent across all subtypes. Motor disability progression as assessed by UPDRS parts 2 and 3 showed significant deterioration over 6-month follow-up across all groups (p < 0.05). Disease progression assessed by PSP-CDS and UMSARS over 6 months was significant (p < 0.05). One PSP and two MSA patients died during a 6-month follow-up period. The hazard ratio in MSA was 3.5 (95% confidence interval: 0.31–0.38) with p = 0.306.

Conclusion Atypical parkinsonian disorders are rare, and usually more severe than idiopathic parkinsonism. As no definitive treatment is available, symptomatic management involving a multidisciplinary team approach must be prioritized.

MicroRNA as Candidate Biomarkers in Atypical Parkinsonian Syndromes: Systematic Literature Review

Background and Objectives: Multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) are rare atypical parkinsonian syndromes, characterized by motor and cognitive symptoms. Their clinical diagnosis is challenging because there are no established biomarkers. Dysregulation of microRNAs (miRNAs/miRs) has been reported to serve an important role in neurodegenerative diseases. However, the miRNA profiles of MSA and PSP patients are rarely reported. The aim of this study was to critically review the role of miRNAs as diagnostic biomarkers to differentiate these atypical parkinsonian disorders and their role in disease pathogenesis. Materials and Methods: A systematic literature search of PubMed was conducted up to February 2022 according the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: A total of 15 studies were analyzed. Three studies have shown that miR-9-3p, miR-19a, miR-19b, and miR-24 are potential biomarkers for MSA. In two studies, miR-132 was downregulated, whereas miR-147a and miR-518e were upregulated in the brain tissue of PSP patients. Conclusions: The potential of miRNA is still uncertain as a potential differential diagnostic marker to identify these disorders. Pre-analytical and analytical factors of included studies were important limitations to justify the introduction of miRNAs into clinical practice.

Clinical and pathological characteristics of later onset multiple system atrophy

BACKGROUND

In the current consensus criteria, onset after age 75 is considered as non-supporting for diagnosis of multiples system atrophy (MSA); however, some MSA patients present after age 75. Clinical and pathological characteristics of such later onset MSA (LO-MSA) compared to usual onset MSA (UO-MSA) remain poorly understood.

METHODS

The clinical cohort included patients from Kobe University Hospital and Amagasaki General Medical Center Hospital, while the autopsy cohort was from the brain bank at Mayo Clinic Florida. We identified 83 patients in the clinical cohort and 193 patients in the autopsy cohort. We divided MSA into two groups according to age at onset: UO-MSA (≤ 75) and LO-MSA (> 75). We compared clinical features and outcomes between the two groups in the clinical cohort and compared the findings to the autopsy cohort.

RESULTS

LO-MSA accounted for 8% in the clinical cohort and 5% in the autopsy cohort. The median time from onset to death or to life-saving tracheostomy was significantly shorter in LO-MSA than in UO-MSA in both cohorts (4.8 vs 7.9 years in the clinical cohort and 3.9 vs 7.5 years in the autopsy cohort; P = 0.043 and P < 0.0001, respectively). The median time from diagnosis to death was less than 3 years in LO-MSA in the clinical cohort.

CONCLUSIONS

Some MSA patients have late age of onset and short survival, limiting time for clinical decision making. MSA should be considered in the differential diagnosis of elderly patients with autonomic symptoms and extrapyramidal and/or cerebellar syndromes.

Heterogeneity of Multiple System Atrophy: An Update

Multiple system atrophy (MSA) is a fatal, rapidly progressing neurodegenerative disease of uncertain etiology, clinically characterized by various combinations of Levodopa unresponsive parkinsonism, cerebellar, autonomic and motor dysfunctions. The morphological hallmark of this α-synucleinopathy is the deposition of aberrant α-synuclein in both glia, mainly oligodendroglia (glial cytoplasmic inclusions /GCIs/) and neurons, associated with glioneuronal degeneration of the striatonigral, olivopontocerebellar and many other neuronal systems. Typical phenotypes are MSA with predominant parkinsonism (MSA-P) and a cerebellar variant (MSA-C) with olivocerebellar atrophy. However, MSA can present with a wider range of clinical and pathological features than previously thought. In addition to rare combined or “mixed” MSA, there is a broad spectrum of atypical MSA variants, such as those with a different age at onset and disease duration, “minimal change” or prodromal forms, MSA variants with Lewy body disease or severe hippocampal pathology, rare forms with an unusual tau pathology or spinal myoclonus, an increasing number of MSA cases with cognitive impairment/dementia, rare familial forms, and questionable conjugal MSA. These variants that do not fit into the current classification of MSA are a major challenge for the diagnosis of this unique proteinopathy. Although the clinical diagnostic accuracy and differential diagnosis of MSA have improved by using combined biomarkers, its distinction from clinically similar extrapyramidal disorders with other pathologies and etiologies may be difficult. These aspects should be taken into consideration when revising the current diagnostic criteria. This appears important given that disease-modifying treatment strategies for this hitherto incurable disorder are under investigation.

Current Progress in the Development of Probes for Targeting α-Synuclein Aggregates

α-Synuclein aggregates abnormally into intracellular inclusions in Parkinson's disease (PD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and many other neurological disorders, closely connecting with their pathogenesis. The accurate tracking of α-synuclein by targeting probes is of great significance for early diagnosis, disease monitoring, and drug development. However, there have been no promising α-synuclein targeting probes for clinical application reported so far. This overview focuses on various potential α-synuclein targeting probes reported in the past two decades, including small-molecule fluorescent probes and radiolabeled probes. We provide the current status of the development of the small molecular α-synuclein imaging probes, including properties of promising imaging molecules, strategies of processing new probes, limited progress, and growth prospects in this field, expecting to help in the further development of α-synuclein targeting probes.

Fatty acid-binding protein 7 triggers α-synuclein oligomerization in glial cells and oligodendrocytes associated with oxidative stress

We previously show that fatty acid-binding protein 3 (FABP3) triggers α-synuclein (Syn) accumulation and induces dopamine neuronal cell death in Parkinson disease mouse model. But the role of fatty acid-binding protein 7 (FABP7) in the brain remains unclear. In this study we investigated whether FABP7 was involved in synucleinopathies. We showed that FABP7 was co-localized and formed a complex with Syn in Syn-transfected U251 human glioblastoma cells, and treatment with arachidonic acid (100 M) significantly promoted FABP7-induced Syn aggregation, which was associated with cell death. We demonstrated that synthetic FABP7 ligand 6 displayed a high affinity against FABP7 with K_d value of 209 nM assessed in 8-anilinonaphthalene-1-sulfonic acid (ANS) assay; ligand 6 improved U251 cell survival via disrupting the FABP7-Syn interaction. We showed that activation of phospholipase A2 (PLA2) by psychosine (10 M) triggered oligomerization of endogenous Syn and FABP7, and induced cell death in both KG-1C human oligodendroglia cells and oligodendrocyte precursor cells (OPCs). FABP7 ligand 6 (1 M) significantly decreased Syn oligomerization and aggregation thereby prevented KG-1C and OPC cell death. This study demonstrates that FABP7 triggers α-synuclein oligomerization through oxidative stress, while FABP7 ligand 6 can inhibit FABP7-induced Syn oligomerization and aggregation, thereby rescuing glial cells and oligodendrocytes from cell death.

Diagnostic work up: Laboratory and biomarkers

This chapter will focus on the diagnostic work around sexual dysfunction in Parkinson's disease, especially laboratory tests and biomarkers. A number of methods to analyze if sexual dysfunction is caused by neural pathology, vascular dysfunction or other mechanisms are now available. Other methods can be used to differentiate between psychogenic/functional reasons behind sexual dysfunction and organic ones. The role of biomarkers for diagnosis, but also for understanding the reason behind and for counteracting sexual dysfunction is becoming more evident. There is also a rich and increasing number of scales and other instruments available for detecting and quantifying sexual hypo- and hyperactivity. When investigating the reason behind sexual dysfunction in patients with Parkinson's disease comorbidities should also be considered. Finally, early and pronounced sexual dysfunction might in some cases be an indication that differential diagnosis, like Multisystem Atrophy, should be thought about. All these aspects of the diagnostic procedures around sexual dysfunction in Parkinson's disease will be covered in this chapter.

Passive Immunization in Alpha-Synuclein Preclinical Animal Models

Alpha-synucleinopathies include Parkinson’s disease, dementia with Lewy bodies, pure autonomic failure and multiple system atrophy. These are all progressive neurodegenerative diseases that are characterized by pathological misfolding and accumulation of the protein alpha-synuclein (αsyn) in neurons, axons or glial cells in the brain, but also in other organs. The abnormal accumulation and propagation of pathogenic αsyn across the autonomic connectome is associated with progressive loss of neurons in the brain and peripheral organs, resulting in motor and non-motor symptoms. To date, no cure is available for synucleinopathies, and therapy is limited to symptomatic treatment of motor and non-motor symptoms upon diagnosis. Recent advances using passive immunization that target different αsyn structures show great potential to block disease progression in rodent studies of synucleinopathies. However, passive immunotherapy in clinical trials has been proven safe but less effective than in preclinical conditions. Here we review current achievements of passive immunotherapy in animal models of synucleinopathies. Furthermore, we propose new research strategies to increase translational outcome in patient studies, (1) by using antibodies against immature conformations of pathogenic αsyn (monomers, post-translationally modified monomers, oligomers and protofibrils) and (2) by focusing treatment on body-first synucleinopathies where damage in the brain is still limited and effective immunization could potentially stop disease progression by blocking the spread of pathogenic αsyn from peripheral organs to the brain.

A Guide for the Differential Diagnosis of Multiple System Atrophy in Clinical Practice

Multiple system atrophy (MSA) is a sporadic and progressive neurodegenerative disorder with a complex differential diagnosis. A range of disorders- also of nondegenerative etiology- can mimic MSA, expanding its differential diagnosis. Both misdiagnosis and diagnostic delays are relatively common in clinical practice. A correct diagnosis is vital for daily clinical practice, in order to facilitate proper counselling and to timely install therapies in treatable disorders that mimic MSA. A correct diagnosis is also essential for including properly classified individuals into research studies that aim to better understand the pathophysiology of MSA, to develop specific biomarkers or to evaluate novel symptomatic or disease-modifying therapies. Here, we offer some practical guidance to support the diagnostic process, by highlighting conditions that may be considered as MSA lookalikes, by emphasizing some key clinical aspects of these mimics, and by discussing several useful ancillary diagnostic tests.

[Role of fatty acid-binding protein 7 and novel therapeutic approach in synucleinopathies]

The synucleinopathies are neurodegenerative disease caused by abnormal accumulation of the 140-amino acid-containing protein α-synuclein (αSyn), including Parkinson's disease (PD), diffuse Lewy body dementia (DLBD), and multiple system atrophy (MSA). In patients with PD and DLBD, αSyn is misfolded in neurons, and its aggregation forms Lewy bodies (LB) and Lewy neurites (LN). On the other hand, in patients with MSA, αSyn accumulates primarily in oligodendrocytes (OLGs) and forms glial inclusion bodies (GCIs), a typical pathological feature of MSA. We recently demonstrated a making complex between αSyn and fatty acid-binding proteins (FABPs) in synucleinopathies and received wide attention. Fatty acid-binding protein 3 (FABP3) in dopamine nerves, and fatty acid-binding protein 7 (FABP7) in glial cells promoted αSyn accumulation and aggregation, respectively and caused cell death. Here, we introduced the current studies about the role of αSyn and FABP7 in MSA and novel therapeutic approach targeting for FABP7.

Depression in multiple system atrophy: Views on pathological, clinical and imaging aspects

Multiple system atrophy (MSA) is a common atypical parkinsonism, characterized by a varying combination of autonomic, cerebellar, and pyramidal systems. It has been noticed that the patients with MSA can be accompanied by some neuropsychiatric disorders, in particular depression. However, there is limited understanding of MSA-related depression. To bridge existing gaps, we summarized research progress on this topic and provided a new perspective regarding pathological, clinical, and imaging aspects. Firstly, we synthesized corresponding studies in order to investigate the relationship between depression and MSA from a pathological perspective. And then, from a clinical perspective, we focused on the prevalence of depression in MS patients and the comparison with other populations. Furthermore, the associations between depression and some clinical characteristics, such as life quality and gender, have been reported. The available neuroimaging studies were too sparse to draw conclusions about the radiological aspect of depression in MSA patients but we still described them in the presence of paper. Finally, we discussed some limitations and shortcomings existing in the included studies, which call for more high-quality basic research and clinical research in this field.