MSA-C is the predominant clinical phenotype of MSA in Japan: Analysis of 142 patients with probable MSA

Proximity proteomics reveals unique and shared pathological features between multiple system atrophy and Parkinson's disease

Synucleinopathies such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA) are neurodegenerative diseases with shared clinical and pathological features. Aggregates of alpha-synuclein (αsyn) phosphorylated at serine 129 (PSER129) are hallmarks of synucleinopathies, which, for PD/DLB, are found predominantly in neurons, whereas in MSA, aggregates are primarily found in oligodendroglia. It remains unclear whether the distinct pathological presentations of PD/DLB and MSA are manifestations of unique or shared pathological processes. Using the in-situ proximity labeling technique of biotinylation by antibody recognition (BAR), we compared aggregated αsyn-interactomes (BAR-PSER129) and total αsyn-interactomes (BAR-MJFR1) between MSA (n = 5) and PD/DLB (n = 10) in forebrain and midbrain structures. Comparison between MSA and PD/DLB-enriched proteins revealed 79 PD/DLB-differentially abundant proteins and only three MSA-differentially abundant proteins (CBR1, CRYAB, and GFAP). Pathway enrichment analysis revealed that vesicle/SNARE-associated pathways dominated PD/DLB interactions, whereas MSA was strongly enriched for metabolic/catabolic, iron, and cellular oxidant detoxification pathways. A subnetwork of cytosolic antioxidant enzymes called peroxiredoxins drove cellular detoxification pathway enrichment in MSA. A network of 26 proteins, including neuronal-specific proteins (e.g., SYNGR3) with HSPA8 at the core, was shared between MSA and DLB/PD. Extracellular exosome pathways were universally enriched regardless of the disease or BAR target protein. In conclusion, synucleinopathies have divergent and convergent αsyn-aggregate interactions, indicating unique and shared pathogenic mechanisms. MSA uniquely involves oxidant detoxification processes in glial cells, while vesicular processes in neurons dominate PD/DLB. Shared interactions, specifically SYNGR3, between MSA and PD/DLB suggest that neuronal axons are the origin of both diseases. In conclusion, we provide αsyn protein interaction maps for two distinct synucleinopathies.

A subgroup of multiple system atrophy with rapid decline in vital capacity

INTRODUCTION

Patients with neurodegenerative disorders resulting in progressive dysphagia often require gastrostomy. Pulmonary function tests (PFTs) are crucial in presurgical evaluation; however, reports on pulmonary function in multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) are limited.

MATERIALS AND METHODS

This single-center, retrospective study analyzed the PFT records from patients with MSA and PSP admitted between January 2012 and October 2023.

RESULTS

Data from 104 PFTs in 70 patients with MSA (21 MSA-P, 49 MSA-C) and 29 PFTs in 22 patients with PSP, showed a weak correlation between the percentage of measured vital capacity to the predicted vital capacity (%VC) and disease duration (MSA: -0.34 and PSP: -0.19). The variation in %VC decline was greater in MSA than in PSP, with a rapid progression (%VC < 65 % within 5 years of disease duration) in seven patients with MSA (6 MSA-P and 1 MSA-C).

CONCLUSION

A decline in %VC with disease duration was observed in both MSA and PSP, with greater variation observed in MSA. Notably, a rapid decline in %VC was predominantly observed in patients with MSA-P during the early courses.

Clinical characteristics and phenoconversion in isolated REM sleep behavior disorder: a prospective single-center study in Korea, compared with Montreal cohort

STUDY OBJECTIVES

Isolated rapid eye movement sleep behavior disorder is a prodromal synucleinopathy, but its conversion rate and subtypes can vary among different cohorts. We report the clinical characteristics and phenoconversion rate of the large single-center isolated rapid eye movement sleep behavior disorder cohort in Korea and compared it to the Montreal cohort.

METHODS

This prospective cohort study examined 238 patients with polysomnography confirmed isolated rapid eye movement sleep behavior disorder from Seoul National University Hospital (SNUH) who completed at least 1 follow-up evaluation. We compared the baseline and phenoconversion data of the SNUH cohort to those of 242 isolated rapid eye movement sleep behavior disorder patients in the Montreal cohort.

RESULTS

In the SNUH cohort, age at rapid eye movement sleep behavior disorder diagnosis was similar (66.4 ± 7.8 vs 65.6 ± 8.4, P = .265), but the proportion of men was lower (63.0% vs 74.0%, P = .01), and the duration of follow-up was shorter than that in the Montreal cohort (3.7 ± 2.0 vs 4.8 ± 3.6 years, P < .001). During follow-up, 34 (11.8%) patients in the SNUH cohort converted to neurodegenerative disease: 18 (52.9%) to Parkinson's disease, 9 (26.5%) to dementia with Lewy bodies, and 7 (20.6%) to multiple system atrophy. The conversion rate in the SNUH cohort was 15% after 3 years, 22% after 5 years, and 32% after 7 years, which was significantly lower than that of the Montreal cohort (log-rank test, P = .002). Among phenoconversion subtype, fewer patients in the SNUH group than in the Montreal group converted to dementia with Lewy bodies (Gray's test P = .001).

CONCLUSIONS

Through a comparative analysis between the SNUH and Montreal cohorts, we identified a significant difference in phenoconversion rates, particularly for dementia with Lewy bodies patients. These findings underscore the importance of further research into the underlying factors, such as racial and geographical factors contributing to such disparities.

CITATION

Byun J-I, Sunwoo J-S, Shin YW, et al. Clinical characteristics and phenoconversion in isolated REM sleep behavior disorder: a prospective single-center study in Korea, compared with Montreal cohort. J Clin Sleep Med. 2025;21(1):81-88.

Comparing alpha-synuclein-interactomes between multiple systems atrophy and Parkinson's disease reveals unique and shared pathological features

Introduction

Primary synucleinopathies, such as Parkinson's disease (PD), Dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), are neurodegenerative disorders with some shared clinical and pathological features. Aggregates of alpha-synuclein (αsyn) phosphorylated at serine 129 (PSER129) are the hallmark of synucleinopathies, which for PD/DLB are found predominantly in neurons (Neuronal cytoplasmic inclusions "NCIs"), but for MSA, aggregates are primarily found in oligodendroglia (Glial cytoplasmic inclusions "GCIs"). It remains unclear if the distinct pathological presentation of PD/DLB and MSA are manifestations of distinct or shared pathological processes. We hypothesize that the distinct synucleinopathies MSA and PD/DLB share common molecular features.

Methods

Using the in-situ proximity labeling technique biotinylation by antibody recognition (BAR), we compare aggregated αsyn-interactomes (BAR-PSER129) and total αsyn-interactomes (BAR-MJFR1) between MSA (n=5) and PD/DLB (n=10) in forebrain and midbrain structures.

Results

For BAR-PSER129 and BAR-MJFR1 captures, αsyn was the most significantly enriched protein in PD/DLB and MSA. In PD/DLB, BAR-PSER129 identified 194 αsyn-aggregate-interacting proteins, while BAR-MJFR1 identified 245 αsyn interacting proteins. In contrast, in the MSA brain, only 38 and 175 proteins were identified for each capture, respectively. When comparing MSA and PD/DLB, a high overlap (59.5%) was observed between BAR-MJFR1 captured proteins, whereas less overlap (14.4%) was observed for BAR-PSER129. Direct comparison between MSA and PD/DLB revealed 79 PD/DLB-associated proteins and only three MSA-associated proteins (CBR1, CRYAB, and GFAP). Pathway enrichment analysis revealed PD/DLB interactions were dominated by vesicle/SNARE-associated pathways, in contrast to MSA, which strongly enriched for metabolic/catabolic, iron, and cellular oxidant detoxification pathways. A subnetwork of cytosolic antioxidant enzymes called peroxiredoxins drove cellular detoxification pathways in MSA. A common network of 26 proteins, including neuronal-specific proteins (e.g., SNYGR3) with HSPA8 at the core, was shared between MSA and DLB/PD. Extracellular exosome pathways were universally enriched regardless of disease or BAR target protein.

Conclusion

Synucleinopathies have divergent and convergent αsyn-aggregate interactions, indicating unique and shared pathogenic mechanisms. MSA uniquely involves oxidant detoxification processes in glial cells, while vesicular processes in neurons dominate PD/DLB. Shared interactions, specifically SNYGR3 (i.e., a neuronal protein), between MSA and PD/DLB suggest neuronal axons origin for both diseases. In conclusion, we provide αsyn aggregates protein interaction maps for two distinct synucleinopathies.

Neurofilament light chain and cardiac MIBG uptake as predictors for phenoconversion in isolated REM sleep behavior disorder

BACKGROUND

Isolated rapid-eye-movement (REM) sleep behavior disorder (iRBD) is considered as a prodromal stage of either multiple system atrophy (MSA) or Lewy body disease (LBD; Parkinson's disease and dementia with Lewy bodies). However, current knowledge is limited in predicting and differentiating the type of future phenoconversion in iRBD patients. We investigated the role of plasma neurofilament light chain (NfL) and cardiac metaiodobenzylguanidine (MIBG) uptake as predictors for phenoconversion.

METHODS

Forty patients with iRBD were enrolled between April 2018 and October 2019 and prospectively followed every 3 months to determine phenoconversion to either MSA or LBD. Plasma NfL levels were measured at enrollment. Cardiac MIBG uptake and striatal dopamine transporter uptake were assessed at baseline.

RESULTS

Patients were followed for a median of 2.92 years. Four patients converted to MSA and 7 to LBD. Plasma NfL level at baseline was significantly higher in future MSA-converters (median 23.2 pg/mL) when compared with the rest of the samples (median 14.1 pg/mL, p = 0.003). NfL level above 21.3 pg/mL predicted phenoconversion to MSA with the sensitivity of 100% and specificity of 94.3%. Baseline MIBG heart-to-mediastinum ratio of LBD-converters (median 1.10) was significantly lower when compared with the rest (median 2.00, p < 0.001). Heart-to-mediastinum ratio below 1.545 predicted phenoconversion to LBD with the sensitivity of 100% and specificity of 92.9%.

CONCLUSIONS

Plasma NfL and cardiac MIBG uptake may be useful biomarkers in predicting phenoconversion of iRBD. Elevated plasma NfL levels may suggest imminent phenoconversion to MSA, whereas low cardiac MIBG uptake suggests phenoconversion to LBD.

Genome-wide association study identifies a new susceptibility locus in PLA2G4C for Multiple System Atrophy

To elucidate the molecular basis of multiple system atrophy (MSA), a neurodegenerative disease, we conducted a genome-wide association study (GWAS) in a Japanese MSA case/control series followed by replication studies in Japanese, Korean, Chinese, European and North American samples. In the GWAS stage rs2303744 on chromosome 19 showed a suggestive association ( P = 6.5 × 10 ^-7 ) that was replicated in additional Japanese samples ( P = 2.9 × 10 ^-6 . OR = 1.58; 95% confidence interval, 1.30 to 1.91), and then confirmed as highly significant in a meta-analysis of East Asian population data ( P = 5.0 × 10 ^-15 . Odds ratio= 1.49; 95% CI 1.35 to 1.72). The association of rs2303744 with MSA remained significant in combined European/North American samples ( P =0.023. Odds ratio=1.14; 95% CI 1.02 to 1.28) despite allele frequencies being quite different between these populations. rs2303744 leads to an amino acid substitution in PLA2G4C that encodes the cPLA2γ lysophospholipase/transacylase. The cPLA2γ-Ile143 isoform encoded by the MSA risk allele has significantly decreased transacylase activity compared with the alternate cPLA2γ-Val143 isoform that may perturb membrane phospholipids and α-synuclein biology.

The High Value of External Anal- and Urethral-Sphincter Electromyography in Differential Diagnosis with MSA-P, PD, and PSP

Objective

It is a challenge to differentiate multiple system atrophy parkinsonism (MSA-P), Parkinson's disease (PD), and progressive supranuclear palsy (PSP). We aimed to explore the value of external anal-sphincter electromyography (EAS-EMG) and urethral-sphincter electromyography (US-EMG) in differential diagnosis with MSA-P, PD, and PSP.

Methods

A total of 149 subjects, including 27 MSA-P, 100 PD, and 22 PSP, were recruited. The average duration and amplitude of motor unit potentials (MUPs), percentage of polyphasic MUPs, amplitude during strong contraction, and recruitment pattern during maximal voluntary contraction were recorded. The differences in EAS-EMG and US-EMG results between MSA-P, PD, and PSP were analyzed.

Results

In EAS-EMG examination, the average duration of MUPs of MSA-P was significantly longer than that of PD and PSP; the percentage of polyphasic MUPs and the ratio of simple phase and simple-mix phase of MSA-P and PSP were significantly higher than that of PD; the amplitude during strong contraction of MSA-P was significantly lower than that of PD. In US-EMG examination, the average duration of MUPs in male MSA-P was significantly longer than that in male PD and PSP; the ratio of simple phase and simple-mix phase in male MSA-P was significantly higher than that in male PD; there was no statistical difference in US-EMG indexes between male PD and PSP male. And because only one female PSP was examined, only female MSA-P and PD were compared, the average duration of MUPs in female MSA-P was significantly longer than that in female PD; the ratio of simple phase and simple-mix phase in female MSA-P was significantly higher than that in female PD.

Conclusion

The average duration of MUPs and the ratio of the simple phase and simple-mix phase of EAS-EMG and US-EMG all can provide the basis for the differential diagnosis between MSA-P and PD. US-EMG can be used as a supplement to differentiate MSA-P from PD when EAS-EMG is limited. The only discriminating indicator between MSA-P and PSP seems to be the average duration of MUPs of EAS-EMG and US-EMG. There is still a lack of diagnostic electromyography indicators between PD and PSP.

Global Epidemiology of Movement Disorders: Rare or Underdiagnosed?

In this manuscript, we review the epidemiology of movement disorders including Parkinson's disease (PD), atypical parkinsonism, essential tremor, dystonia, functional movement disorders, tic disorders, chorea, and ataxias. We emphasize age-, sex-, and geography-based incidence and prevalence, as well as notable trends including the rising incidence and prevalence of PD. Given the growing global interest in refining clinical diagnostic skills in recognizing movement disorders, we highlight some key epidemiological findings that may be of interest to clinicians and health systems tasked with diagnosing and managing the health of patients with movement disorders.

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.

COVID-19 pandemic and the international classification of functioning in multiple system atrophy: a cross-sectional, nationwide survey in Japan

The present study aimed to determine the magnitude of and risk factors for the effects of the COVID-19 pandemic on the international classification of functioning, disability and health (ICF) in patients with multiple system atrophy (PwMSA). The study was part of a cross-sectional, nationwide, multipurpose mail survey for Japanese PwMSA from October to December, 2020. The primary outcome was the impact of the early COVID-19 pandemic on ICF functioning, consisting of body function, activity, and participation. Age, sex, disease type, disease duration, and dwelling place were asked as participants’ characteristics, and the multiple system impairment questionnaire (MSIQ), patient health questionnaire-2, modified rankin scale, barthel index, life-space assessment (LSA), and EuroQoL were examined. Multivariate logistic regression analyses were performed to identify independent risk factors for a worse function score due to the COVID-19 pandemic for each ICF functioning domain. A total of 155 patients (mean age 65.6 [SD 8.1] years; 43.9% women; mean disease duration 8.0 [SD 6.2] years; 65% MSA with cerebellar ataxia, 13% MSA with parkinsonism, 9% MSA with predominant autonomic features) were analyzed. Of the ICF functioning domains, the respondents reported that the early COVID-19 pandemic affected body function in 17.4%, activity in 17.6%, and participation in 46.0%. The adjusted multivariate model identified MSIQ and LSA as the two variables that independently contributed to all domains. The COVID-19 pandemic affected ICF functioning of PwMSA in Japan, and the severity of disease-related impairments and a large daily living space were common risk factors. These results help support the focus on patient characteristics for medical and social welfare support.

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.

A historical review of multiple system atrophy with a critical appraisal of cellular and animal models

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterized by striatonigral degeneration (SND), olivopontocerebellar atrophy (OPCA), and dysautonomia with cerebellar ataxia or parkinsonian motor features. Isolated autonomic dysfunction with predominant genitourinary dysfunction and orthostatic hypotension and REM sleep behavior disorder are common characteristics of a prodromal phase, which may occur years prior to motor-symptom onset. MSA is a unique synucleinopathy, in which alpha-synuclein (aSyn) accumulates and forms insoluble inclusions in the cytoplasm of oligodendrocytes, termed glial cytoplasmic inclusions (GCIs). The origin of, and precise mechanism by which aSyn accumulates in MSA are unknown, and, therefore, disease-modifying therapies to halt or slow the progression of MSA are currently unavailable. For these reasons, much focus in the field is concerned with deciphering the complex neuropathological mechanisms by which MSA begins and progresses through the course of the disease. This review focuses on the history, etiopathogenesis, neuropathology, as well as cell and animal models of MSA.

Essential Tremor Within the Broader Context of Other Forms of Cerebellar Degeneration

Essential tremor (ET) has recently been reconceptualized by many as a degenerative disease of the cerebellum. Until now, though, there has been no attempt to frame it within the context of these diseases. Here, we compare the clinical and postmortem features of ET with other cerebellar degenerations, thereby placing it within the broader context of these diseases. Action tremor is the hallmark feature of ET. Although often underreported in the spinocerebellar ataxias (SCAs), action tremors occur, and it is noteworthy that in SCA12 and 15, they are highly prevalent, often severe, and can be the earliest disease manifestation, resulting in an initial diagnosis of ET in many cases. Intention tremor, sometimes referred to as "cerebellar tremor," is a common feature of ET and many SCAs. Other features of cerebellar dysfunction, gait ataxia and eye motion abnormalities, are seen to a mild degree in ET and more markedly in SCAs. Several SCAs (e.g., SCA5, 6, 14, and 15), like ET, follow a milder and more protracted disease course. In ET, numerous postmortem changes have been localized to the cerebellum and are largely confined to the cerebellar cortex, preserving the cerebellar nuclei. Purkinje cell loss is modest. Similarly, in SCA3, 12, and 15, Purkinje cell loss is limited, and in SCA12 and 15, there is preservation of cerebellar nuclei and relative sparing of other central nervous system regions. Both clinically and pathologically, there are numerous similarities and intersection points between ET and other disorders of cerebellar degeneration.

Magnetic resonance imaging abnormalities as a marker of multiple system atrophy in isolated rapid eye movement sleep behavior disorder

STUDY OBJECTIVES

Patients with isolated rapid eye movement (REM) sleep behavior disorder (IRBD) develop Parkinson disease (PD), dementia with Lewy bodies (DLB), or multiple system atrophy (MSA). Magnetic resonance imaging (MRI) is abnormal in MSA showing abnormalities in the putamen, cerebellum, and brainstem. Our objective was to evaluate the usefulness of MRI to detect MRI abnormalities in IRBD and predict development of MSA and not PD and DLB.

METHODS

In IRBD patients that eventually developed PD, DLB, and MSA, we looked for the specific structural MRI abnormalities described in manifest MSA (e.g. hot cross-bun sign, putaminal rim, and cerebellar atrophy). We compared the frequency of these MRI changes among groups of converters (PD, DLB, and MSA) and analyzed their ability to predict development of MSA. The clinical and radiological features of the IRBD patients that eventually converted to MSA are described in detail.

RESULTS

A total of 61 IRBD patients who underwent MRI phenoconverted to PD (n = 30), DLB (n = 26), and MSA (n = 5) after a median follow-up of 2.4 years from neuroimaging. MRI changes typical of MSA were found in four of the five (80%) patients who converted to MSA and in three of the 56 (5.4%) patients who developed PD or DLB. MRI changes of MSA had sensitivity of 80.0%, specificity of 94.6%, positive likelihood ratio of 14.9 (95% CI 4.6-48.8), and negative likelihood ratio of 0.2 (95% CI 0.04-1.2) to predict MSA.

CONCLUSIONS

In IRBD, conventional brain MRI is helpful to predict conversion to MSA. The specific MRI abnormalities of manifest MSA may be detected in its premotor stage.

Potential Fluid Biomarkers and a Prediction Model for Better Recognition Between Multiple System Atrophy-Cerebellar Type and Spinocerebellar Ataxia

Objective

This study screened potential fluid biomarkers and developed a prediction model based on the easily obtained information at initial inspection to identify ataxia patients more likely to have multiple system atrophy-cerebellar type (MSA-C).

Methods

We established a retrospective cohort with 125 ataxia patients from southwest China between April 2018 and June 2020. Demographic and laboratory variables obtained at the time of hospital admission were screened using Least Absolute Shrinkage and Selection Operator (LASSO) regression and logistic regression to construct a diagnosis score. The receiver operating characteristic (ROC) and decision curve analyses were performed to assess the accuracy and net benefit of the model. Also, independent validation using 25 additional ataxia patients was carried out to verify the model efficiency. Then the model was translated into a visual and operable web application using the R studio and Shiny package.

Results

From 47 indicators, five variables were selected and integrated into the prediction model, including the age of onset (AO), direct bilirubin (DBIL), aspartate aminotransferase (AST), eGFR, and synuclein-alpha. The prediction model exhibited an area under the curve (AUC) of 0.929 for the training cohort and an AUC of 0.917 for the testing cohort. The decision curve analysis (DCA) plot displayed a good net benefit for this model, and external validation confirmed its reliability. The model also was translated into a web application that is freely available to the public.

Conclusion

The prediction model that was developed based on laboratory and demographic variables obtained from ataxia patients at admission to the hospital might help improve the ability to differentiate MSA-C from spinocerebellar ataxia clinically.

Fatty Acid-Binding Protein 3 Expression in the Brain and Skin in Human Synucleinopathies

Parkinson’s disease (PD) and multiple system atrophy are types of adult-onset neurodegenerative disorders named synucleinopathies, which are characterized by prominent intracellular α-synuclein (αSyn) aggregates. We have previously found that αSyn aggregates and the vulnerability of dopaminergic neurons in the mouse brain are partly associated with the expression of fatty acid-binding protein 3 (FABP3, heart FABP). However, it remains to be elucidated whether FABP3 accumulation is associated with αSyn aggregates in human tissues. Here, we histologically studied FABP3 expression in human tissues obtained from patients with synucleinopathies, patients with Alzheimer disease (AD) and controls. We found that (1) a variety of neurons expressed the FABP3 protein in human brain tissues, (2) FABP3 was colocalized with αSyn aggregates in the brains of individuals with synucleinopathies but not with amyloid β or p-tau aggregates in the brains of individuals with AD, and (3) FABP3 was not present in p-αSyn deposits in biopsied skin tissues from individuals with PD. These findings suggest that FABP3 expression is associated with αSyn aggregation in synucleinopathies and provide new insights into the involvement of FABP3 in synucleinopathies.

Multiple system atrophy in Hokkaido, Japan: a prospective registry study of natural history and symptom assessment scales followed for 5 years

OBJECTIVES

Multiple system atrophy (MSA) is a refractory neurodegenerative disease, but novel treatments are anticipated. An accurate natural history of MSA is important for clinical trials, but is insufficient. This regional registry was launched to complement clinical information on MSA.

SETTING

Patient recruitment started in November 2014 and is ongoing at the time of submission. The number of participating facilities was 66. Postal surveys were sent to medical facilities and patients with MSA in Hokkaido, Japan.

PARTICIPANTS

After obtaining written consent from 196 participants, 184 overview surveys and 115 detailed surveys were conducted.

PRIMARY AND SECONDARY OUTCOME MEASURES

An overview survey evaluated conformity to diagnostic criteria and a detailed survey implemented an annual assessment based on the Unified Multiple System Atrophy Rating Scale (UMSARS).

RESULTS

At the time of registration, 58.2% of patients were diagnosed with cerebellar symptoms predominant type MSA (MSA-C) and 29.9% were diagnosed with parkinsonism predominant type MSA (MSA-P). UMSARS Part Ⅳ score of 4 or 5 accounted for 53.8% of participants. The higher the UMSARS Part Ⅳ score, the higher the proportion of MSA-P. At baseline, levodopa was used by 69 patients (37.5%) and the average levodopa dose was 406.7 mg/day. The frequency of levodopa use increased over time. Eleven cases changed from MSA-C to MSA-P during the study, but the opposite was not observed. Information about survival and causes of death was collected on 54 cases. Half of deaths were respiratory-related. Sudden death was recorded even in the group with UMSARS Part Ⅳ score of 1.

CONCLUSIONS

This study is the first large-scale prospective MSA cohort study in Asia. MSA-C was dominant, but the use of antiparkinsonian drugs increased over the study period. Changes from MSA-C to MSA-P occurred, but not vice versa.

Mood and emotional disorders associated with parkinsonism, Huntington disease, and other movement disorders

This chapter provides a review of mood, emotional disorders, and emotion processing deficits associated with diseases that cause movement disorders, including Parkinson's disease, Lewy body dementia, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, frontotemporal dementia with parkinsonism, Huntington's disease, essential tremor, dystonia, and tardive dyskinesia. For each disorder, a clinical description of the common signs and symptoms, disease progression, and epidemiology is provided. Then the mood and emotional disorders associated with each of these diseases are described and discussed in terms of clinical presentation, incidence, prevalence, and alterations in quality of life. Alterations of emotion communication, such as affective speech prosody and facial emotional expression, associated with these disorders are also discussed. In addition, if applicable, deficits in gestural and lexical/verbal emotion are reviewed. Throughout the chapter, the relationships among mood and emotional disorders, alterations of emotional experiences, social communication, and quality of life, as well as treatment, are emphasized.

A distinct neuromelanin magnetic resonance imaging pattern in parkinsonian multiple system atrophy

Background

Parkinsonian variant of multiple system atrophy is a neurodegenerative disorder frequently misdiagnosed as Parkinson’s disease. No early imaging biomarkers currently differentiate these disorders.

Methods

Simple visual imaging analysis of the substantia nigra and locus coeruleus in neuromelanin-sensitive magnetic resonance imaging and nigrosome 1 in susceptibility-weighted sequences was performed in thirty patients with parkinsonian variant of multiple system atrophy fulfilling possible/probable second consensus diagnostic criteria. The neuromelanin visual pattern was compared to patients with Parkinson’s disease with the same disease duration (n = 10) and healthy controls (n = 10). Substantia nigra semi-automated neuromelanin area/signal intensity was compared to the visual data.

Results

Groups were similar in age, sex, disease duration, and levodopa equivalent dose. Hoehn & Yahr stage was higher in parkinsonian multiple system atrophy patients, 69% of whom had normal neuromelanin size/signal, significantly different from Parkinson’s disease patients, and similar to controls. Nigrosome 1 signal was lost in 74% of parkinsonian multiple system atrophy patients. Semi-automated neuromelanin substantia nigra signal, but not area, measurements were able to differentiate groups.

Conclusions

In patients with parkinsonism, simple visual magnetic resonance imaging analysis showing normal neuromelanin substantia nigra and locus coeruleus, combined with nigrosome 1 loss, allowed the distinction of the parkinsonian variant of multiple system atrophy from Parkinson’s disease and healthy controls. This easy and widely available method was superior to semi-automated measurements in identifying specific imaging changes in substantia nigra and locus coeruleus.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-020-02007-5.

Gastrointestinal dysfunction in the synucleinopathies

Interest in gastrointestinal dysfunction in Parkinson's disease has blossomed over the past 30 years and has generated a wealth of investigation into this non-motor aspect of the disorder, research that has encompassed its pathophysiology, its clinical features, and its impact on quality of life. The question of gastrointestinal dysfunction in the other synucleinopathies has not received nearly as much attention, but information and knowledge are growing. In this review, the current knowledge, controversies, and gaps in our understanding of the pathophysiology of gastrointestinal dysfunction in Parkinson's disease and the other synucleinopathies will be addressed, and extended focus will be directed toward the clinical problems involving saliva management, swallowing, gastric emptying, small intestinal function, and bowel function that are so problematic in these disorders.

Magnetic resonance T1w/T2w ratio in the middle cerebellar peduncle might be a sensitive biomarker for multiple system atrophy

OBJECTIVE

We aimed to investigate the use of a myelin-sensitive MRI contrast, the standardized T1-weighted/T2-weighted (sT1w/T2w) ratio, for detecting early changes in the middle cerebellar peduncle (MCP) in cerebellar subtype multiple system atrophy (MSA-C) patients.

METHODS

We included 28 MSA-C patients, including a subset of 17 MSA-C patients within 2 years of disease onset (early MSA-C), and 28 matched healthy controls. T1w and T2w scans were acquired using a 3-T MR system. The sT1w/T2w ratio in MCP was analyzed using SPM12 by utilizing a region-of-interest approach in normalized space. The diagnostic performance of the MCP sT1w/T2w ratio in discriminating MSA-C and the subgroup of early MSA-C from the matched controls was assessed. Correlation analyses were performed to evaluate the relationship between the MCP sT1w/T2w ratio and other clinical parameters including the International Cooperative Ataxia Scale (ICARS) score for quantifying cerebellar ataxia.

RESULTS

Compared to controls, the sT1w/T2w ratio in the MCP was markedly lower in all (p < 0.001) MSA-C patients and 17 early (p < 0.001) MSA-C patients. The MCP sT1w/T2w ratio had high sensitivity (96%) and specificity (100%) to distinguish MSA-C from controls (area under the curve = 0.99), even for the early MSA-C group (area under the curve = 0.99; sensitivity = 94%, specificity = 100%). The MCP sT1w/T2w ratio correlated with the ICARS score in early MSA-C.

CONCLUSIONS

The sT1w/T2w ratio can detect MSA-C-related changes in the MCP, even in the early stages of the disorder, and could be a sensitive biomarker for MSA-C.

KEY POINTS

• The sT1w/T2w ratio can detect MSA-C-related changes in the middle cerebellar peduncle, even in the early stages of the disorder. • The middle cerebellar peduncle sT1w/T2w ratio correlated with a cerebellar ataxia score in early MSA-C patients.

3-Hz Postural Tremor in MSA-C and SCA: Revisiting an Old but Underestimated Cerebellar Sign by Posturography

The aim of this study is to evaluate the prevalence and electrophysiological features of 3-Hz postural tremor in multiple system atrophy-cerebellar type and spinocerebellar ataxia. A static posturography examination was administered to 37 persons with spinocerebellar ataxia, 58 others with the cerebellar type of multiple system atrophy, and 53 healthy controls. During the sensory organization tests of 5 multiple system atrophy patients, surface electromyograms were recorded from bilateral tibialis anterior and medial gastrocnemius muscles. The patients with multiple system atrophy had, on average, significantly higher scores on the International Cooperative Ataxia Rating Scale and significantly greater prevalence of cross sign. Almost 80% of them fell during the posturography testing compared with two-thirds of the spinocerebellar ataxia patients. Twenty-seven percent of the spinocerebellar ataxia patients and 82.8% of those with multiple system atrophy displayed postural tremor with a frequency of approximately 3 Hz. The tremor's frequency tended to be lower in the spinocerebellar ataxia patients. The surface electromyography revealed highly coherent tremor activity at about 3 Hz in the patients' bilateral tibialis anterior and alternating firing in the bilateral antagonist muscles. Combining cross sign with a subject's static score of the International Cooperative Ataxia Rating Scale and occurrence of the tremor produced an indicator able to differentiate the two conditions with a sensitivity of 87.9% and a specificity of 89.2%. The area under the receiver operating characteristics curve for the indicator was 0.942. Three-hertz postural tremor is relatively characteristic of cerebellar type of multiple system atrophy and appears at an early stage of the disease. Identification of the tremor by posturography will facilitate its diagnosis.

Sacral Reflex Characteristics of Patients with Multiple System Atrophy

Objectives

To observe and analyze the parameters of the sacral reflex and pudendal nerve somatosensory evoked potential (SSEP) in patients with multiple system atrophy (MSA) with respect to factors such as age, disease course, and subtype and provide evidence for the clinical diagnosis of MSA.

Materials and Methods

A total of 51 MSA patients and 30 healthy controls were selected from the First Affiliated Hospital of Wenzhou Medical University from May 2013 to November 2015. Electrophysiological sacral reflex detection and SSEP detection were performed using the Keypoint EMG/EP system. The extraction rate, latency, and amplitude of the sacral reflex and SSEP in the MSA group and control group were compared.

Results

The sacral reflex latency and amplitude in patients with MSA were statistically different from those of the healthy controls. The latency of sacral reflex increases with the prolongation of the disease course, and the amplitude and initiation rate decrease with the prolongation of the disease course. There was no significant difference in sacral reflex latency and amplitude between MSA patients of different ages and subtypes. There was no significant difference in the latency or amplitude of SSEP between the MSA group and healthy control group.

Conclusions

The latency of sacral reflex increases with the prolongation of the disease course, and the amplitude and extraction rate decrease with the prolongation of the disease course. There was no significant difference in the parameters of sacral reflex between young MSA patients and elderly patients. And there was no statistically significant difference between MSA-P subtypes and MSA-C subtypes. This trial is registered with ISRCTNCR2009041.

Vertical pons hyperintensity and hot cross bun sign in cerebellar-type multiple system atrophy and spinocerebellar ataxia type 3

Background

The “hot cross bun” (HCB) sign, a cruciform hyperintensity in the pons on magnetic resonance imaging (MRI), has gradually been identified as a typical finding in multiple system atrophy, cerebellar-type (MSA-C). Few reports have evaluated the sensitivity of an HCB, including a cruciform hyperintensity and vertical line in the pons, which precedes a cruciform hyperintensity, in the early stages of MSA-C. Moreover, the difference in frequency and timing of appearance of an HCB between MSA-C and spinocerebellar ataxia type 3 (SCA3) has not been fully investigated.

Methods

This study investigated the time at which an HCB and orthostatic hypotension (OH) appeared in 41 patients with MSA-C, based on brain MRI and head-up tilt test. The MRI findings were compared with those of 26 patients with SCA3. The pontine signal findings on T2-weighted MRI were graded as 0 (no change), 1 (a vertical T2 high-intensity line), or 2 (a cruciform T2 high-intensity line), with grades 1 or 2 considered as an HCB. OH 30/15 was defined as a decrease in systolic blood pressure of > 30 mmHg or diastolic blood pressure of > 15 mmHg.

Results

Among the 24 patients with MSA-C within 2 years from the onset of motor symptoms, an HCB was detected in 91.7%, whereas OH 30/15 was present in 60.0%. Among the 36 patients with MSA-C within 3 years from the onset of motor symptoms, a grade 2 HCB was detected in 66.7% of those with MSA-C but in none of those with SCA-3.

Conclusions

HCB is a highly sensitive finding for MSA-C, even in the early stages of the disease. A grade 2 HCB in the early stage is an extremely specific finding for differentiating MSA-C from SCA-3.

Diagnosing multiple system atrophy at the prodromal stage

Identifying individuals at the earliest disease stage becomes crucial as we aim to develop disease-modifying treatments for neurodegenerative disorders. Prodromal diagnostic criteria were recently developed for Parkinson's disease (PD) and are forthcoming for dementia with Lewy bodies (DLB). The latest 2008 version of diagnostic criteria for multiple system atrophy (MSA) have improved diagnostic accuracy in early disease stages compared to previous criteria, but we do not yet have formal criteria for prodromal MSA. Building on similar approaches as for PD and DLB, we can identify features on history-taking, clinical examination, and ancillary clinical testing that can predict the likelihood of an individual developing MSA, while also distinguishing it from PD and DLB. The main clinical hallmarks of MSA are REM sleep behavior disorder (RBD) and autonomic dysfunction (particularly orthostatic hypotension and urogenital symptoms), and may be the primary means by which patients with potential prodromal MSA are identified. Preserved olfaction, absence of significant cognitive deficits, urinary retention, and respiratory symptoms such as stridor and respiratory insufficiency can be clinical features that help distinguish MSA from PD and DLB. Finally, ancillary test results including neuroimaging as well as serological and cerebrospinal fluid (CSF) biomarkers may lend further weight to quantifying the likelihood of phenoconversion into MSA. For prodromal criteria, the primary challenges are MSA's lower prevalence, shorter lead time to diagnosis, and strong overlap with other synucleinopathies. Future prodromal criteria may need to first embed the diagnosis into a general umbrella of prodromal alpha-synucleinopathies, followed by identification of features that suggest prodromal MSA as the specific cause.

MSA: From basic mechanisms to experimental therapeutics

Multiple system atrophy (MSA) is a rare and fatal neurodegenerative disorder characterized by rapidly progressive autonomic and motor dysfunction. Pathologically, MSA is mainly characterized by the abnormal accumulation of misfolded α-synuclein in the cytoplasm of oligodendrocytes, which plays a major role in the pathogenesis of the disease. Striatonigral degeneration and olivopontecerebellar atrophy underlie the motor syndrome, while degeneration of autonomic centers defines the autonomic failure in MSA. At present, there is no treatment that can halt or reverse its progression. However, over the last decade several studies in preclinical models and patients have helped to better understand the pathophysiological events underlying MSA. The etiology of this fatal disorder remains unclear and may be multifactorial, caused by a combination of factors which may serve as targets for novel therapeutic approaches. In this review, we summarize the current knowledge about the etiopathogenesis and neuropathology of MSA, its different preclinical models, and the main disease modifying therapies that have been used so far or that are planned for future clinical trials.

Changes in clinical features of multiple system atrophy in Japan

Introduction

Methods

Results

Conclusion

•

We investigated the clinical features of 80 probable MSA patients.

•

We compared two groups of probable MSA patients according to the period of diagnosis.

•

MSA with predominant cerebellar ataxia (MSA-C) was predominant in both groups.

•

MSA with predominant parkinsonism (MSA-P) increased in the recent diagnosis group.

•

Aging and development of examination tools may have influenced these results.

Models of multiple system atrophy

Multiple system atrophy (MSA) is a neurodegenerative disease with diverse clinical manifestations, including parkinsonism, cerebellar syndrome, and autonomic failure. Pathologically, MSA is characterized by glial cytoplasmic inclusions in oligodendrocytes, which contain fibrillary forms of α-synuclein. MSA is categorized as one of the α-synucleinopathy, and α-synuclein aggregation is thought to be the culprit of the disease pathogenesis. Studies on MSA pathogenesis are scarce relative to studies on the pathogenesis of other synucleinopathies, such as Parkinson’s disease and dementia with Lewy bodies. However, recent developments in cellular and animal models of MSA, especially α-synuclein transgenic models, have driven advancements in research on this disease. Here, we review the currently available models of MSA, which include toxicant-induced animal models, α-synuclein-overexpressing cellular models, and mouse models that express α-synuclein specifically in oligodendrocytes through cell type-specific promoters. We will also discuss the results of studies in recently developed transmission mouse models, into which MSA brain extracts were intracerebrally injected. By reviewing the findings obtained from these model systems, we will discuss what we have learned about the disease and describe the strengths and limitations of the models, thereby ultimately providing direction for the design of better models and future research.

A review of the models available for studying multiple system atrophy (MSA), a Parkinson’s-like disease, may help identify new treatment options. MSA is difficult to diagnose and unresponsive to drugs. Similar to Parkinson’s disease, it involves accumulation of protein aggregates in brain and spinal cord cells, but the causes are poorly understood. He-Jin Lee at Konkuk University, and Seung-Jae Lee at Seoul National University College of Medicine in South Korea and coworkers have reviewed the models available to study the disease, including toxin-induced and transgenic animal models, and recent evidence that transferring the protein aggregates into cells causes MSA symptoms. Each model mimics some aspects of the disease, but none captures the full range of symptoms. This review helps highlight research pathways that may illuminate treatments for this complex and debilitating adult-onset disease.

A case of multiple system atrophy

Multiple system atrophy (MSA) is the most rapidly progressive neurodegenerative disorder among the various types of synucleinopathies. The cause of MSA remains unknown, but it can involve the extrapyramidal system, the pyramidal system, the autonomic nerves and the cerebellum. The main clinical manifestations are Parkinson's symptoms, cerebellar ataxia, pyramidal tract signs and autonomic nervous system disorders. Depending on the initial predominant motor deficits, MSA is subclassified into either Parkinsonian type (MSA-P) or cerebellar type (MSA-C). MSA is rare in the Zunyi area of Guizhou Province, so when it is observed for the first time it often results in a convoluted diagnosis and treatment process, which takes a lot of time, money, manpower and material resources, which can also have a psychological impact on the patient. This report describes the case of a 60-year-old woman who presented with syncope for 1 year combined with dizziness for 1 day. She had been diagnosed twice with transient ischaemic attack in the previous 6 months. Cranial magnetic resonance imaging suggested widening of the cerebellar sulcus and mild cerebellar atrophy. Based on the patient’s medical history, physical signs and auxiliary examinations, she was diagnosed with MSA-C.

Parkinsonian syndromes: A review

Since James Parkinson published his remarkable clinical observations in the "An Essay On The Shaking Palsy" in 1817, the number of diseases included in the spectrum of parkinsonian syndromes (a group of diseases that have some part of their clinical features resembling those seen in Parkinson's disease), are growing. Careful history taking, comprehensive neurological examination, and utilization of proper investigations will lead the physicians to make an accurate diagnosis of the specific disease entity present. In this recent review, we cover the issue of classification of parkinsonian syndromes, and comprehensively review the characteristic features of the commonly encountered diseases that present with this syndrome. The salient aspects of the epidemiology, key clinical features, proper investigations, and possible treatment options of these diseases have also been addressed.

Dissecting α-synuclein inclusion pathology diversity in multiple system atrophy: implications for the prion-like transmission hypothesis

Synucleinopathies are a group of neurodegenerative diseases characterized by the accumulation of insoluble, aggregated α-synuclein (αS) pathological inclusions. Multiple system atrophy (MSA) presents with extensive oligodendroglial αS pathology and additional more limited neuronal inclusions while most of the other synucleinopathies, such as Parkinson's disease and dementia with Lewy bodies (DLB), develop αS pathology primarily in neuronal cell populations. αS biochemical alterations specific to MSA have been described but thorough examination of these unique and disease-specific protein deposits is further warranted especially given recent findings implicating the prion-like nature of synucleinopathies perhaps with distinct strain-like properties. Taking advantage of an extensive panel of antibodies that target a wide range of epitopes within αS, we investigated the distinct properties of the various types of αS inclusion present in MSA brains with comparison to DLB. Brain biochemical fractionation followed by immunoblotting revealed that the immunoreactive profiles were significantly more consistent for DLB than for MSA. Furthermore, epitope-specific immunohistochemistry varied greatly between different types of MSA αS inclusions and even within different brain regions of individual MSA brains. These studies highlight the importance of using a battery of antibodies for adequate appreciation of the various pathology in this distinct synucleinopathy. In addition, it can be posited that if the spread of pathology in MSA undergoes prion-like mechanisms, "strains" of αS aggregated conformers must be inherently unstable and readily mutable, perhaps resulting in a more stochastic progression process.

Neuropathology and pathogenesis of extrapyramidal movement disorders: a critical update-I. Hypokinetic-rigid movement disorders

Extrapyramidal movement disorders include hypokinetic rigid and hyperkinetic or mixed forms, most of them originating from dysfunction of the basal ganglia (BG) and their information circuits. The functional anatomy of the BG, the cortico-BG-thalamocortical, and BG-cerebellar circuit connections are briefly reviewed. Pathophysiologic classification of extrapyramidal movement disorder mechanisms distinguish (1) parkinsonian syndromes, (2) chorea and related syndromes, (3) dystonias, (4) myoclonic syndromes, (5) ballism, (6) tics, and (7) tremor syndromes. Recent genetic and molecular-biologic classifications distinguish (1) synucleinopathies (Parkinson's disease, dementia with Lewy bodies, Parkinson's disease-dementia, and multiple system atrophy); (2) tauopathies (progressive supranuclear palsy, corticobasal degeneration, FTLD-17; Guamian Parkinson-dementia; Pick's disease, and others); (3) polyglutamine disorders (Huntington's disease and related disorders); (4) pantothenate kinase-associated neurodegeneration; (5) Wilson's disease; and (6) other hereditary neurodegenerations without hitherto detected genetic or specific markers. The diversity of phenotypes is related to the deposition of pathologic proteins in distinct cell populations, causing neurodegeneration due to genetic and environmental factors, but there is frequent overlap between various disorders. Their etiopathogenesis is still poorly understood, but is suggested to result from an interaction between genetic and environmental factors. Multiple etiologies and noxious factors (protein mishandling, mitochondrial dysfunction, oxidative stress, excitotoxicity, energy failure, and chronic neuroinflammation) are more likely than a single factor. Current clinical consensus criteria have increased the diagnostic accuracy of most neurodegenerative movement disorders, but for their definite diagnosis, histopathological confirmation is required. We present a timely overview of the neuropathology and pathogenesis of the major extrapyramidal movement disorders in two parts, the first one dedicated to hypokinetic-rigid forms and the second to hyperkinetic disorders.

Identification of plasma microRNA expression changes in multiple system atrophy and Parkinson's disease

MicroRNAs (miRNAs) are endogenous small (18–25 nt), single-stranded, non-coding RNAs that play key roles in post-transcriptional gene expression regulation. The expression profiles of miRNAs in biofluids and tissues change in various diseases. Multiple system atrophy (MSA) and Parkinson’s disease (PD) are both categorized as α-synucleinopathies and often present with similar clinical manifestations. This study aimed to identify miRNAs that are differently expressed in plasma samples of PD patients, MSA patients, and healthy controls. We used microarray analysis to screen for miRNAs that are up- and down-regulated in these patients and analyzed the relative-quantitative expression levels of the identified miRNAs by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Hsa-miR-671-5p, hsa-miR-19b-3p, and hsa-miR-24-3p showed significantly different expression levels among patients with MSA-C, MSA-P, or PD, and healthy controls. Hsa-miR-671-5p levels were lower in the MSA-P and PD than the MSA-C and control groups, hsa-miR-19b-3p levels were higher in the PD than the other groups, and hsa-miR-24-3p levels were higher in the PD than the MSA-C group. Hsa-miR-671-5p was the first miRNA shown to be expressed differently between MSA-C and MSA-P in plasma. Interestingly, the expression levels of hsa-miR-19b-3p and hsa-miR-24-3p were positively correlated, indicating that these miRNAs may be involved in the same processes in PD pathogenesis. Our findings suggest that hsa-miR-671-5p, hsa-miR-19b-3p, and hsa-miR-24-3p may reflect the pathophysiology or symptoms of PD and MSA.

The severity of motor dysfunctions and urinary dysfunction is not correlated in multiple system atrophy

OBJECTIVE

Although it is well known that patients with multiple system atrophy (MSA) cerebellar dominant type (MSA-C) show severe autonomic dysfunction, the relationship between autonomic and motor dysfunction remains uncertain. Previously we reported that severe urinary voiding dysfunction is useful in differential diagnosis of MSA and other diseases. Herein, we aimed to clarify the relationship between the severity of motor dysfunctions and urinary dysfunction.

METHOD

This study is a retrospective review of 46 patients with MSA-C diagnosed according to Gilman's second consensus criteria. The severity of motor dysfunctions was evaluated using International Cooperative Ataxia Rating Scale (ICARS). Urinary voiding dysfunction was evaluated by measuring post-void residual (PVR). The mean duration of motor unit potentials in external anal sphincter muscles on electromyography, which represents the severity of neurodegeneration in Onuf's nucleus, was also examined.

RESULTS

The mean age of patients was 63.8 ± 8.2 years and mean disease duration was 3.0 ± 1.9 years. The mean ICARS score was 40.1 ± 14.7. The mean PVR was 119.1 ± 102 ml and the mean duration of motor unit potentials (MUPs) in anal sphincter electromyography was 9.2 ± 2.2 ms. The correlation coefficient between ICARS and PVR was 0.093 (p = .539), and between ICARS and mean duration of MUPs was 0.105 (p = .811). A significant positive correlation (r = 0.296, p = .005) was noted between PVR and the mean duration of MUP.

CONCLUSION

Motor and urinary dysfunctions were not correlated in MSA-C.

Altered structural connectivity of the motor subnetwork in multiple system atrophy with cerebellar features

OBJECTIVES

To investigate the structural connectivity of the motor subnetwork in multiple system atrophy with cerebellar features (MSA-C), a distinct subtype of MSA, characterized by predominant cerebellar symptoms.

METHODS

Twenty-three patients with MSA-C and 25 age- and gender-matched healthy controls were recruited for the study. Disease severity was quantified using the Unified Multiple System Atrophy Rating Scale (UMSARS). Diffusion MRI images were acquired and used to compute the structural connectomes (SCs) using probabilistic fiber tracking. The motor network with 12 brain regions and 26 cerebellar regions was extracted and was compared between the groups using analysis of variance at a global (network-wide), nodal (at each node), and edge (at each connection) levels, and was corrected for multiple comparisons. In addition, the acquired connectivity measures were correlated with duration of illness, total Unified MSA Rating Scale (UMSARS), and the motor component score.

RESULTS

Significantly lower global network metrics-global density, transitivity, clustering coefficient, and characteristic path length-were observed in MSA-C (corrected p < 0.05). Reduced nodal strength was observed in the bilateral ventral diencephalon, the left thalamus, and several cerebellar regions. Network-based statistics revealed significant abnormal edge-wise connectivity in 40 connections (corrected p < 0.01), with majority of deficits observed in the cerebellum. Finally, significant negative correlations were observed between UMSARS scores and thalamic and cerebellar connectivity (p < 0.05) as well as between duration of illness and cerebellar connectivity.

CONCLUSIONS

Abnormal connectivity of the basal ganglia and cerebellar network may be causally implicated for the motor features observed in MSA-C.

KEY POINTS

• Structural connectivity of the motor subnetwork was explored in patients with multiple system atrophy with cerebellar features (MSA-C) using probabilistic tractography. • The motor subnetwork in MSA-C has significant alterations in both basal ganglia and cerebellar connectivity, with a higher extent of abnormality in the cerebellum. • These findings may be causally implicated for the motor features of cerebellar dysfunction and parkinsonism observed in MSA-C.

Clinical characteristics and quality of life in Chinese patients with multiple system atrophy

OBJECTIVES

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder that causes early sustained disability and poor health-related quality of life (HrQoL). The clinical features and their effects on the HrQoL of patients in China have received little attention in the research literature. We evaluated the clinical characteristics and HrQoL of Chinese patients with MSA.

MATERIALS AND METHODS

A total of 143 patients with MSA from the Department of Neurology, Shanghai Ruijin Hospital, were enrolled in the study from March 2014 to May 2017. Basic demographic data, motor symptoms, non-motor symptoms, and HrQoL were assessed and compared with data from 198 patients with idiopathic Parkinson's disease (PD) who were matched by age, gender, and disease duration. Factors influencing the HrQoL of MSA patients were also analyzed.

RESULTS

The ratio of patients with predominant parkinsonism (MSA-P) and prominent cerebellar ataxia (MSA-C) was 95:48 among the 143 MSA patients. MSA-P patients had a longer disease duration (p = 0.002), higher levodopa equivalent daily dose (p < 0.001), higher scores on the Unified Multiple System Atrophy Rating Scale (UMSARS) I (p = 0.026), UMSARS II (p < 0.001), UMSARS IV (p = 0.019), the Hamilton Rating Scale for Depression (p = 0.001), the Hamilton Anxiety Scale (p = 0.013), and lower scores on measures of olfaction (p = 0.021) and cognitive function (p = 0.044) than the MSA-C patients. Stepwise regression analysis showed that depression, anxiety, degree of disability, and disease severity were independent predictors of decreased HrQoL.

CONCLUSIONS

The results indicate that MSA-P patients have more severe motor impairment, hyposmia, depression, anxiety, cognitive impairment, and lower HrQoL than MSA-C patients. Depression, anxiety, degree of disability, and disease severity are predictors of poor HrQoL among Chinese patients with MSA.

Exploring bedside clinical features of parkinsonism: A focus on differential diagnosis

The proper diagnosis of parkinsonian disorders usually involves three steps: identifying core features of parkinsonism; excluding other causes; and collating supportive evidence based on clinical signs or investigations. While the recognition of cardinal parkinsonian features is usually straightforward, the appreciation of clinical features suggestive of specific parkinsonian disorders can be challenging, and often requires greater experience and skills. In this review, we outline the clinical features that are relevant to the differential diagnosis of common neurodegenerative parkinsonian disorders, including Parkinson's disease, multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration. We aim to make this process relatable to clinicians-in-practice, therefore, have categorised the list of clinical features into groups according to the typical sequence on how clinicians would elicit them during the examination, starting with observation of facial expression and clinical signs of the face, spotting eye movement abnormalities, examination of tremors and jerky limb movements, and finally, examination of posture and gait dysfunction. This review is not intended to be comprehensive. Rather, we have focused on the most common clinical signs that are potentially key to making the correct diagnosis and those that do not require special skills or training for interpretation. Evidence is also provided, where available, such as diagnostic criteria, consensus statements, clinicopathological studies or large multi-centre registries. Pitfalls are also discussed when relevant to the diagnosis. While no clinical signs are pathognomonic for certain parkinsonian disorders, certain clinical clues may assist in narrowing a differential diagnosis and tailoring focused investigations for the individual patient.

Serum antigliadin antibodies in cerebellar ataxias: a systematic review and meta-analysis

BACKGROUND

Gluten sensitivity refers to prominent immunological responses to gluten, usually in conjunction with elevated levels of serum antigliadin antibody (AGA). The association between AGA and cerebellar ataxias has been inconsistently reported.

METHODS

We performed a systematic literature search and a meta-analysis to study the weighted pooled OR of idiopathic cerebellar ataxia (IDCA) cases to controls or to hereditary ataxia (HA) for AGA seropositivity using fixed effect model.

RESULTS

Eleven studies were included, with a total of 847 IDCA cases, 1654 controls and 445 HA cases. IDCA cases had fourfold higher odds than controls (OR 4.28, 95% CI 3.10 to 5.90) and twofold higher odds than HA cases (OR 2.23, 95% CI 1.45 to 3.44) of having AGA seropositivity. Sensitivity analysis excluding the most weighted study, which accounted for 69% of the total weight, still showed similar associations (IDCA vs controls, OR 3.18, 95% CI 1.79 to 5.67 and IDCA vs HA, OR 1.72, 95% CI 1.03 to 2.86, respectively). The subgroup analysis showed that, when compared with controls, IDCA cases of both East Asian and Western countries had approximately threefold to fourfold higher odds to have AGA seropositivity (OR 3.41, 95% CI 1.67 to 6.97 and OR 4.53, 95% CI 3.16 to 6.49, respectively), suggesting the lack of ethnic heterogeneity. The odds of AGA seropositivity for HA cases was not significantly higher than controls (OR 1.41, 95% CI 0.82 to 2.44).

CONCLUSION

Our study indicates the association between AGA and IDCA, across different geographic regions.

The pathogenesis linked to coenzyme Q10 insufficiency in iPSC-derived neurons from patients with multiple-system atrophy

Multiple-system atrophy (MSA) is a neurodegenerative disease characterized by autonomic failure with various combinations of parkinsonism, cerebellar ataxia, and pyramidal dysfunction. We previously reported that functionally impaired variants of COQ2, which encodes an essential enzyme in the biosynthetic pathway of coenzyme Q10, are associated with MSA. Here, we report functional deficiencies in mitochondrial respiration and the antioxidative system in induced pluripotent stem cell (iPSC)-derived neurons from an MSA patient with compound heterozygous COQ2 mutations. The functional deficiencies were rescued by site-specific CRISPR/Cas9-mediated gene corrections. We also report an increase in apoptosis of iPSC-derived neurons from MSA patients. Coenzyme Q10 reduced apoptosis of neurons from the MSA patient with compound heterozygous COQ2 mutations. Our results reveal that cellular dysfunctions attributable to decreased coenzyme Q10 levels are related to neuronal death in MSA, particularly in patients with COQ2 variants, and may contribute to the development of therapy using coenzyme Q10 supplementation.

Possible multiple system atrophy with predominant parkinsonism in a patient with chronic schizophrenia: a case report

BACKGROUND

Multiple system atrophy (MSA) is an adult-onset, rare, and progressive neurodegenerative disorder characterized by a varying combination of autonomic failure, cerebellar ataxia, and parkinsonism. MSA is categorized as MSA-P with predominant parkinsonism, and as MSA-C with predominant cerebellar features. The prevalence of MSA has been reported to be between 1.86 and 4.9 cases per 100,000 individuals. In contrast, approximately 1% of the population is affected by schizophrenia during their lifetime; therefore, MSA-P comorbidity is very rare in schizophrenic patients. However, when the exacerbation or progression of parkinsonism occurs in patients with schizophrenia treated with antipsychotics, it is necessary to consider rare neurodegenerative disorders, including MSA-P, in the differential diagnosis of parkinsonism.

CASE PRESENTATION

A 60-year-old female patient with chronic schizophrenia developed possible MSA-P. She had been treated mainly with typical antipsychotics, and presented with urinary incontinence, nocturnal polyuria, and dysarthria around 2011. In 2014, she developed worsening parkinsonian symptoms and autonomic dysfunction. Although her antipsychotic medication was switched to an atypical antipsychotic and the dose reduced, her parkinsonism was not improved. In 2015, modified electroconvulsive therapy produced slight improvements in the symptoms; however, she shortly returned to her symptomatic state. A combination of cardiac ¹²³I-meta-iodobenzylguanidine scintigraphy and ¹²³I-FP-CIT single-photon emission computed tomography imaging, in addition to brain magnetic resonance imaging findings, helped to discriminate MSA-P from other sources of parkinsonism. L-dopa had been prescribed, but she responded poorly and died in the spring of 2016.

CONCLUSIONS

This case report highlights the importance of considering MSA-P in the differential diagnosis for parkinsonism in a patient being treated with antipsychotics for chronic schizophrenia. MSA-P should be considered in patients presenting with worsening and progressing parkinsonism, especially when accompanied by autonomic dysfunction or cerebellar ataxia. Although a definite diagnosis of MSA-P requires autopsy confirmation, a combination of brain magnetic resonance imaging and nuclear medicine scans may help to differentiate suspected MSA-P from the other parkinsonian syndromes. This case also demonstrates that MSA with parkinsonism that is poorly responsive to L-dopa may improve shortly after modified electroconvulsive therapy without worsening psychiatric symptoms.

Recent advances in neuropathology, biomarkers and therapeutic approach of multiple system atrophy

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterised by a variable combination of autonomic failure, levodopa-unresponsive parkinsonism, cerebellar ataxia and pyramidal symptoms. The pathological hallmark is the oligodendrocytic glial cytoplasmic inclusion (GCI) consisting of α-synuclein; therefore, MSA is included in the category of α-synucleinopathies. MSA has been divided into two clinicopathological subtypes: MSA with predominant parkinsonism and MSA with predominant cerebellar ataxia, which generally correlate with striatonigral degeneration and olivopontocerebellar atrophy, respectively. It is increasingly recognised, however, that clinical and pathological features of MSA are broader than previously considered.In this review, we aim to describe recent advances in neuropathology of MSA from a review of the literature and from information derived from review of nearly 200 definite MSA cases in the Mayo Clinic Brain Bank. In light of these new neuropathological findings, GCIs and neuronal cytoplasmic inclusions play an important role in clinicopathological correlates of MSA. We also focus on clinical diagnostic accuracy and differential diagnosis of MSA as well as candidate biomarkers. We also review some controversial topics in MSA. Cognitive impairment, which has been a non-supporting feature of MSA, is considered from both clinical and pathological perspectives. The cellular origin of α-synuclein in GCI and a 'prion hypothesis' are discussed. Finally, completed and ongoing clinical trials targeting disease modification, including immunotherapy, are summarised.

Multiple System Atrophy: An Oligodendroglioneural Synucleinopathy1

Multiple system atrophy (MSA) is an orphan, fatal, adult-onset neurodegenerative disorder of uncertain etiology that is clinically characterized by various combinations of parkinsonism, cerebellar, autonomic, and motor dysfunction. MSA is an α-synucleinopathy with specific glioneuronal degeneration involving striatonigral, olivopontocerebellar, and autonomic nervous systems but also other parts of the central and peripheral nervous systems. The major clinical variants correlate with the morphologic phenotypes of striatonigral degeneration (MSA-P) and olivopontocerebellar atrophy (MSA-C). While our knowledge of the molecular pathogenesis of this devastating disease is still incomplete, updated consensus criteria and combined fluid and imaging biomarkers have increased its diagnostic accuracy. The neuropathologic hallmark of this unique proteinopathy is the deposition of aberrant α-synuclein in both glia (mainly oligodendroglia) and neurons forming glial and neuronal cytoplasmic inclusions that cause cell dysfunction and demise. In addition, there is widespread demyelination, the pathogenesis of which is not fully understood. The pathogenesis of MSA is characterized by propagation of misfolded α-synuclein from neurons to oligodendroglia and cell-to-cell spreading in a "prion-like" manner, oxidative stress, proteasomal and mitochondrial dysfunction, dysregulation of myelin lipids, decreased neurotrophic factors, neuroinflammation, and energy failure. The combination of these mechanisms finally results in a system-specific pattern of neurodegeneration and a multisystem involvement that are specific for MSA. Despite several pharmacological approaches in MSA models, addressing these pathogenic mechanisms, no effective neuroprotective nor disease-modifying therapeutic strategies are currently available. Multidisciplinary research to elucidate the genetic and molecular background of the deleterious cycle of noxious processes, to develop reliable biomarkers and targets for effective treatment of this hitherto incurable disorder is urgently needed.

Multiple system atrophy: experimental models and reality

Multiple system atrophy (MSA) is a rapidly progressing fatal synucleinopathy of the aging population characterized by parkinsonism, dysautonomia, and in some cases ataxia. Unlike other synucleinopathies, in this disorder the synaptic protein, α-synuclein (α-syn), predominantly accumulates in oligodendroglial cells (and to some extent in neurons), leading to maturation defects of oligodendrocytes, demyelination, and neurodegeneration. The mechanisms through which α-syn deposits occur in oligodendrocytes and neurons in MSA are not completely clear. While some studies suggest that α-syn might transfer from neurons to glial cells, others propose that α-syn might be aberrantly overexpressed by oligodendroglial cells. A number of in vivo models have been developed, including transgenic mice overexpressing α-syn under oligodendroglial promoters (e.g.: MBP, PLP, and CNP). Other models have been recently developed either by injecting synthetic α-syn fibrils or brain homogenates from patients with MSA into wild-type mice or by using viral vectors expressing α-syn under the MBP promoter in rats and non-human primates. Each of these models reproduces some of the neuropathological and functional aspects of MSA; however, none of them fully replicate the spectrum of MSA. Understanding better the mechanisms of how α-syn accumulates in oligodendrocytes and neurons will help in developing better models that recapitulate various pathogenic aspects of MSA in combination with translatable biomarkers of early stages of the disease that are necessary to devise disease-modifying therapeutics for MSA.

Genomic copy number variation analysis in multiple system atrophy

Genomic variation includes single-nucleotide variants, small insertions or deletions (indels), and copy number variants (CNVs). CNVs affect gene expression by altering the genome structure and transposable elements within a region. CNVs are greater than 1 kb in size; hence, CNVs can produce more variation than can individual single-nucleotide variations that are detected by next-generation sequencing. Multiple system atrophy (MSA) is an α-synucleinopathy adult-onset disorder. Pathologically, it is characterized by insoluble aggregation of filamentous α-synuclein in brain oligodendrocytes. Generally, MSA is sporadic, although there are rare cases of familial MSA. In addition, the frequencies of the clinical phenotypes differ considerably among countries. Reports indicate that genetic factors play roles in the mechanisms involved in the pathology and onset of MSA. To evaluate the genetic background of this disorder, we attempted to determine whether there are differences in CNVs between patients with MSA and normal control subjects. We found that the number of CNVs on chromosomes 5, 22, and 4 was increased in MSA; 3 CNVs in non-coding regions were considered risk factors for MSA. Our results show that CNVs in non-coding regions influence the expression of genes through transcription-related mechanisms and potentially increase subsequent structural alterations of chromosomes. Therefore, these CNVs likely play roles in the molecular mechanisms underlying MSA.

The neuropathology of multiple system atrophy and its therapeutic implications

Multiple system atrophy (MSA) is a fatal neurodegenerative disorder characterized by the abnormal accumulation of toxic forms of the synaptic protein alpha-synuclein (α-syn) within oligodendrocytes and neurons. The presence of α-syn within oligodendrocytes in the form of glial cytoplasmic inclusions is the diagnostic hallmark of MSA. However, it has been postulated that α-syn is produced in neurons and propagates to oligodendrocytes, where unknown mechanisms lead to its accumulation. The presence of α-syn within neurons in MSA has not been so extensively studied, but it may shed light into neuropathological mechanisms leading to oligodendroglial accumulation. Here we summarize the principal neuropathological events of MSA, and discuss how a deeper knowledge of these mechanisms may help develop effective therapies targeting α-syn accumulation and spreading.

The Diagnosis and Natural History of Multiple System Atrophy, Cerebellar Type

The objective of this study was to identify key features differentiating multiple system atrophy cerebellar type (MSA-C) from idiopathic late-onset cerebellar ataxia (ILOCA). We reviewed records of patients seen in the Massachusetts General Hospital Ataxia Unit between 1992 and 2013 with consensus criteria diagnoses of MSA-C or ILOCA. Twelve patients had definite MSA-C, 53 had possible/probable MSA-C, and 12 had ILOCA. Autonomic features, specifically urinary urgency, frequency, and incontinence with erectile dysfunction in males, differentiated MSA-C from ILOCA throughout the disease course (p = 0.005). Orthostatic hypotension developed later and differentiated MSA-C from ILOCA (p < 0.01). REM sleep behavior disorder (RBD) occurred early in possible/probable MSA-C (p < 0.01). Late MSA-C included pathologic laughing and crying (PLC, p < 0.01), bradykinesia (p = 0.01), and corticospinal findings (p = 0.01). MRI distinguished MSA-C from ILOCA by atrophy of the brainstem (p < 0.01) and middle cerebellar peduncles (MCP, p = 0.02). MSA-C progressed faster than ILOCA: by 6 years, MSA-C walker dependency was 100 % and ILOCA 33 %. MSA-C survival was 8.4 ± 2.5 years. Mean length of ILOCA illness to date is 15.9 ± 6.4 years. A sporadic onset, insidiously developing cerebellar syndrome in midlife, with autonomic features of otherwise unexplained bladder dysfunction with or without erectile dysfunction in males, and atrophy of the cerebellum, brainstem, and MCP points strongly to MSA-C. RBD and postural hypotension confirm the diagnosis. Extrapyramidal findings, corticospinal tract signs, and PLC are helpful but not necessary for diagnosis. Clarity in early MSA-C diagnosis can prevent unnecessary investigations and facilitate therapeutic trials.