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Background: Mild cognitive impairment is one of the non-motor symptoms in Parkinson's disease (PD) and multiple system atrophy (MSA). Few studies have previously been conducted on the correlation between serum uric acid (SUA) and lipid levels and mild cognitive impairment in PD and MSA., Methods: Participants included 149 patients with PD and 99 patients with MSA. The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were used to evaluate cognitive function. Evaluations were conducted on SUA and lipid levels, which included triglyceride, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and total cholesterol (TC)., Results: Patients with PD and MSA diagnosed with mild cognitive impairment demonstrated multiple cognitive domain impairment when compared with patients with normal cognition. Attentional impairment was more pronounced in patients with MSA when compared with PD ( p = 0.001). In PD, the risk of mild cognitive impairment was lower in the highest quartiles and secondary quartile of SUA than in the lowest quartiles (odds ratio [OR] = 0.281, 95% confidence intervals [CI]: 0.097-0.810, p = 0.019; and OR = 0.317, 95% CI: 0.110-0.911, p = 0.033). In MSA, the risk of mild cognitive impairment was lower in the third and highest quartile of SUA than in the lowest quartile (OR = 0.233, 95% CI: 0.063-0.868, p = 0.030; and OR = 0.218, 95% CI: 0.058-0.816, p = 0.024). In patients with PD, the MoCA scores were negatively correlated with TC levels ( r = -0.226, p = 0.006) and positively correlated with SUA levels ( r = 0.206, p = 0.012). In MSA, the MoCA scores were positively correlated with SUA levels ( r = 0.353, p = 0.001)., Conclusions: Lower SUA levels and higher TC levels are a possible risk factor for the risk and severity of mild cognitive impairment in PD. Lower SUA levels are a possible risk factor for the risk and severity of mild cognitive impairment in MSA., (© 2024 The Author(s). Published by IMR Press.)

Early and precise diagnosis of α-synucleinopathies is challenging but critical. In this study, we developed a molecular beacon-based assay to evaluate microRNA-containing extracellular vesicles (EVs) in plasma. We recruited 1203 participants including healthy controls (HCs) and patients with isolated REM sleep behavior disorder (iRBD), α-synucleinopathies, or non-α-synucleinopathies from eight centers across China. Plasma miR-44438-containing EV levels were significantly increased in α-synucleinopathies, including those in the prodromal stage (e.g., iRBD), compared to both non-α-synucleinopathy patients and HCs. However, there are no significant differences between Parkinson's disease (PD) and multiple system atrophy. The miR-44438-containing EV levels negatively correlated with age and the Hoehn and Yahr stage of PD patients, suggesting a potential association with disease progression. Furthermore, a longitudinal analysis over 16.3 months demonstrated a significant decline in miR-44438-containing EV levels in patients with PD. These results highlight the potential of plasma miR-44438-containing EV as a biomarker for early detection and progress monitoring of α-synucleinopathies.

The diagnosis of Parkinson's disease (PD) and atypical parkinsonian syndromes is difficult due to the lack of reliable, easily accessible biomarkers. Multiple system atrophy (MSA) is a synucleinopathy whose symptoms often overlap with PD. Exosomes isolated from blood by immunoprecipitation using CNS markers provide a window into the brain's biochemistry and may assist in distinguishing between PD and MSA. Thus, we asked whether α-synuclein (α-syn) in such exosomes could distinguish among healthy individuals, patients with PD, and patients with MSA. We isolated exosomes from the serum or plasma of these three groups by immunoprecipitation using neuronal and oligodendroglial markers in two independent cohorts and measured α-syn in these exosomes using an electrochemiluminescence ELISA. In both cohorts, α-syn concentrations were significantly lower in the control group and significantly higher in the MSA group compared to the PD group. The ratio between α-syn concentrations in putative oligodendroglial exosomes compared to putative neuronal exosomes was a particularly sensitive biomarker for distinguishing between PD and MSA. Combining this ratio with the α-syn concentration itself and the total exosome concentration, a multinomial logistic model trained on the discovery cohort separated PD from MSA with an AUC = 0.902, corresponding to 89.8% sensitivity and 86.0% specificity when applied to the independent validation cohort. The data demonstrate that a minimally invasive blood test measuring α-syn in blood exosomes immunoprecipitated using CNS markers can distinguish between patients with PD and patients with MSA with high sensitivity and specificity. Future optimization and validation of the data by other groups would allow this strategy to become a viable diagnostic test for synucleinopathies., (© 2021. The Author(s).)

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Introduction: Ubiquitous naturally occurring autoantibodies (nAbs) against alpha-synuclein (α-syn) may play important roles in the pathogenesis of Multiple System Atrophy (MSA) and Parkinson's disease (PD). Recently, we reported reduced high-affinity/avidity anti-α-syn nAbs levels in plasma from MSA and PD patients, along with distinct inter-group immunoglobulin (Ig)G subclass distributions. The extent to which these observations in plasma may reflect corresponding levels in the cerebrospinal fluid (CSF) is unknown., Methods: Using competitive and indirect ELISAs, we investigated the affinity/avidity of CSF anti-α-syn nAbs as well as the CSF and plasma distribution of IgG subclasses and IgM nAbs in a cross-sectional cohort of MSA and PD patients., Results: Repertoires of high-affinity/avidity anti-α-syn IgG nAbs were reduced in CSF samples from MSA and PD patients compared to controls. Furthermore, anti-α-syn IgM nAb levels were relatively lower in CSF and plasma from MSA patients but were reduced only in plasma from PD patients. Interestingly, anti-α-syn IgG subclasses presented disease-specific profiles both in CSF and plasma. Anti-α-syn IgG1, IgG2 and IgG3 levels were relatively increased in CSF of MSA patients, whereas PD patients showed increased anti-α-syn IgG2 and reduced anti-α-syn IgG4 levels., Conclusions: Differences in the plasma/CSF distribution of anti-α-syn nAbs seem to be a common feature of synucleinopathies. Our data add further support to the notion that MSA and PD patients may have compromised immune reactivity towards α-syn. The differing α-syn-specific systemic immunological responses may reflect their specific disease pathophysiologies. These results are encouraging for further investigation of these immunological mechanisms in neurodegenerative diseases., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

MicroRNAs are reportedly involved in the pathogenesis of neurodegenerative diseases, including Parkinson's disease and multiple system atrophy. We previously identified 7 differentially expressed microRNAs in Parkinson's disease patients and control sera (miR-30c, miR-31, miR-141, miR-146b-5p, miR-181c, miR-214, and miR-193a-3p). To investigate the expression levels of the 7 serum microRNAs in Parkinson's disease and multiple system atrophy, 23 early Parkinson's disease patients (who did not take any anti- Parkinson's disease drugs), 23 multiple system atrophy patients, and 24 normal controls were recruited at outpatient visits in this study. The expression levels of the 7 microRNAs in serum were detected using quantitative real-time polymerase chain reaction. A receiver operating characteristic curve was used to evaluate whether microRNAs can differentially diagnose Parkinson's disease and multiple system atrophy. Clinical scales were used to analyze the correlations between serum microRNAs and clinical features. The results indicated that miR-214 could distinguish Parkinson's disease from the controls, and another 3 microRNAs could differentiate multiple system atrophy from the controls (miR-141, miR-193a-3p, and miR-30c). The expression of miR-31, miR-141, miR-181c, miR-193a-3p, and miR-214 were lower in multiple system atrophy than in Parkinson's disease (all P < 0.05). Combinations of microRNAs accurately discriminated Parkinson's disease from multiple system atrophy (area under the receiver operating characteristic curve = 0.951). For the correlation analysis, negative correlations were discovered between the expression of miR-214 and the Hamilton Anxiety Scale and Parkinson's Disease Non-Motor Symptom scores (all P < 0.05). Our results demonstrate that the distinctive characteristics of microRNAs differentiate Parkinson's disease and multiple system atrophy patients from healthy controls and may be used for the early diagnosis of Parkinson's disease and multiple system atrophy., Competing Interests: All authors declare no conflicts of interest., (© 2020 Yan et al. Published by IMR press.)

Objective: Parkinson's disease is characterised neuropathologically by α-synuclein aggregation. Currently, there is no blood test to predict the underlying pathology or distinguish Parkinson's from atypical parkinsonian syndromes. We assessed the clinical utility of serum neuronal exosomes as biomarkers across the spectrum of Parkinson's disease, multiple system atrophy and other proteinopathies., Methods: We performed a cross-sectional study of 664 serum samples from the Oxford, Kiel and Brescia cohorts consisting of individuals with rapid eye movement sleep behavioural disorder, Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, frontotemporal dementia, progressive supranuclear palsy, corticobasal syndrome and controls. Longitudinal samples were analysed from Parkinson's and control individuals. We developed poly(carboxybetaine-methacrylate) coated beads to isolate L1 cell adhesion molecule (L1CAM)-positive extracellular vesicles with characteristics of exosomes and used mass spectrometry or multiplexed electrochemiluminescence to measure exosomal proteins., Results: Mean neuron-derived exosomal α-synuclein was increased by twofold in prodromal and clinical Parkinson's disease when compared with multiple system atrophy, controls or other neurodegenerative diseases. With 314 subjects in the training group and 105 in the validation group, exosomal α-synuclein exhibited a consistent performance (AUC=0.86) in separating clinical Parkinson's disease from controls across populations. Exosomal clusterin was elevated in subjects with non-α-synuclein proteinopathies. Combined neuron-derived exosomal α-synuclein and clusterin measurement predicted Parkinson's disease from other proteinopathies with AUC=0.98 and from multiple system atrophy with AUC=0.94. Longitudinal sample analysis showed that exosomal α-synuclein remains stably elevated with Parkinson's disease progression., Conclusions: Increased α-synuclein egress in serum neuronal exosomes precedes the diagnosis of Parkinson's disease, persists with disease progression and in combination with clusterin predicts and differentiates Parkinson's disease from atypical parkinsonism., Competing Interests: Competing interests: HW and JR are employees of Eli Lilly and Company., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.)

Background: Multiple system atrophy (MSA) is a rare oligodendroglial synucleinopathy of unknown etiopathogenesis including two major clinical variants with predominant parkinsonism (MSA-P) or cerebellar dysfunction (MSA-C)., Objective: To identify novel disease mechanisms we performed a blood transcriptomic study investigating differential gene expression changes and biological process alterations in MSA and its clinical subtypes., Methods: We compared the transcriptome from rigorously gender and age-balanced groups of 10 probable MSA-P, 10 probable MSA-C cases, 10 controls from the Catalan MSA Registry (CMSAR), and 10 Parkinson Disease (PD) patients., Results: Gene set enrichment analyses showed prominent positive enrichment in processes related to immunity and inflammation in all groups, and a negative enrichment in cell differentiation and development of the nervous system in both MSA-P and PD, in contrast to protein translation and processing in MSA-C. Gene set enrichment analysis using expression patterns in different brain regions as a reference also showed distinct results between the different synucleinopathies., Conclusions: In line with the two major phenotypes described in the clinic, our data suggest that gene expression and biological processes might be differentially affected in MSA-P and MSA-C. Future studies using larger sample sizes are warranted to confirm these results.

Introduction: Adiponectin receptors are expressed in the hypothalamus, brainstem, and basal ganglia. Experimentally, adiponectin was immunopositive in the phosphorylated α-synuclein-positive Lewy bodies in the brain of individuals with Parkinson's disease (PD), and treatment with recombinant adiponectin suppressed the aggregation of α-synuclein. The close relationship between adiponectin and PD is suggested., Methods: We assessed whether adiponectin levels may increase in patients with PD and differ in individuals with other neurodegenerative diseases. Blood samples were stored at - 70 °C. Adiponectin levels were measured using a latex turbidimetric immunoassay., Results: Adiponectin levels of patients with PD (p = 0.019) or PD plus multiple systemic atrophy with predominant parkinsonian features (MSA-P) (p = 0.034) increased compared with those of patients with progressive supranuclear palsy (PSP). A multivariate comparison using ANCOVA showed that the adiponectin level was significantly higher in PD plus MSA-P than in patient with PSP, which is independent of age and BMI (adjusted mean difference of 4.388 μg/ml [95% confidence interval 0.602-8.174, p = 0.024]). A significant positive correlation between adiponectin and HDL-C levels was observed in patients with PD on a single linear regression analysis (β, 0.257; p < 0.001; R 2  = 0.271). The results were not significant in patients with MSA-P, PSP, and MSA-P plus PSP., Conclusions: Adiponectin is likely to play roles in the composition of lipid rafts since the adiponectin level of each patient with alpha-synucleinopathy or PSP differed.

Objective: To investigate the oxidized albumin ratio, which is the redox ratio of human nonmercaptalbumin (HNA) to serum albumin (%HNA), as a biomarker in idiopathic Parkinson's disease (iPD) and related neurodegenerative disorders., Methods: This prospective study enrolled 216 iPD patients, 15 patients with autosomal recessive familial PD due to parkin mutations (PARK2), 30 multiple system atrophy (MSA) patients, 32 progressive nuclear palsy (PSP) patients, and 143 healthy controls. HNA was analyzed using modified high-performance liquid chromatography and was evaluated alongside other parameters., Results: iPD and PARK2 patients had a higher %HNA than controls (iPD vs. controls: odds ratio (OR) 1.325, P < 0.001; PARK2 vs. controls: OR 1.712, P < 0.001). Even iPD patients at an early Hoehn & Yahr stage (I and II) showed a higher %HNA than controls. iPD patients had a higher %HNA than MSA and PSP patients (iPD vs. MSA: OR 1.249, P < 0.001, iPD vs. PSP: OR 1.288, P < 0.05). When discriminating iPD patients from controls, %HNA corrected by age achieved an AUC of 0.750; when discriminating iPD patients from MSA and PSP patients, an AUC of 0.747 was achieved. Furthermore, uric acid, an antioxidant compound, was decreased in iPD patients, similar to the change in %HNA., Interpretation: %HNA was significantly increased in iPD and PARK2 patients compared with controls, regardless of disease course and severity. Oxidative stress might be increased from the early stages of iPD and PARK2 and play an important role in their pathomechanisms., (© 2020 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals, Inc on behalf of American Neurological Association.)

Aggregation of alpha-synuclein (α-syn) is considered to be the major pathological hallmark and driving force of Multiple System Atrophy (MSA) and Parkinson's disease (PD). Immune dysfunctions have been associated with both MSA and PD and recently we reported that the levels of natural occurring autoantibodies (NAbs) with high-affinity/avidity toward α-synuclein are reduced in MSA and PD patients. Here, we aimed to evaluate the plasma immunoglobulin (Ig) composition binding α-syn and other amyloidogenic neuropathological proteins, and to correlate them with disease severity and duration in MSA and PD patients. All participants were recruited from a single neurological unit and the plasma samples were stored for later research at the Bispebjerg Movement Disorder Biobank. All patients were diagnosed according to current consensus criteria. Using multiple variable linear regression analyses, we observed higher levels of anti-α-syn IgG1 and IgG3 NAbs in MSA vs. PD, higher levels of anti-α-syn IgG2 NAbs in PD compared to controls, whereas anti-α-syn IgG4 NAbs were reduced in PD compared to MSA and controls. Anti-α-syn IgM levels were decreased in both MSA and PD. Further our data supported that MSA patients' immune system was affected with reduced IgG1 and IgM global levels compared to PD and controls, with further reduced global IgG2 levels compared to PD. These results suggest distinct autoimmune patterns in MSA and PD. These findings suggest a specific autoimmune physiological mechanism involving responses toward α-syn, differing in neurodegenerative disease with overlapping α-syn pathology., (Copyright © 2019 Folke, Rydbirk, Løkkegaard, Salvesen, Hejl, Starhof, Bech, Winge, Christensen, Pedersen, Aznar, Pakkenberg and Brudek.)

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.

Objective: To investigate the diagnostic value of serum neurofilament light chain (NFL) in patients with clear signs of parkinsonism but whose specific diagnosis was yet uncertain., Methods: Serum samples were collected from patients with clear signs of parkinsonism but with uncertain diagnosis at the inclusion. Clinical diagnoses of Parkinson disease (PD) and atypical parkinsonism disorders (APDs) were established after 3 years of follow-up and updated again after a maximum of 12 years in case longer follow-up data were available. Serum NFL was quantified by single molecule array in patients with PD (n = 55) and APD (n = 29, multiple system atrophy = 22, progressive supranuclear palsy = 7) and 53 nonneurologic controls., Results: Serum NFL levels were elevated and differentiated the APD group (mean 23.8 ± 10.3 ng/L) from PD (mean 10.4 ± 4.9 ng/L) and controls (mean 11.5 ± 6.5 ng/L, p < 0.0001) with accuracy levels up to 91% (sensitivity = 86% and specificity = 85%). Serum NFL strongly correlated with CSF NFL levels ( r = 0.72, p < 0.0001) in all groups and with age in PD ( r = 0.78, p < 0.0001) and controls ( r = 0.66, p < 0.0001). In our cohort, the probability of having APD was 76% (positive predictive value) and of having PD 92% (negative predictive value)., Conclusion: Serum NFL levels are markedly elevated in APD compared to PD and discriminate APDs from PD with high accuracy. Serum NFL may be a useful clinical biomarker to identify APD, even at stages when clinical symptoms are not yet conclusive., Classification of Evidence: This study provides Class II evidence that serum NFL levels accurately discriminate APDs from PD., (© 2019 American Academy of Neurology.)

Background: Parkinson's disease (PD) is the result of progressive degeneration of the nigrostriatal dopaminergic pathway and depletion of neurotransmitter dopamine in the striatum., Methods: We included 17 patients with PD along with 7 patients of progressive supranuclear palsy (PSP), 6 patients of multiple system atrophy (MSA) and 22 age and sex-matched healthy controls. We analyzed metabolite profiles in the serum of these patients and controls using 1 H NMR spectroscopy., Results: Isoleucine, valine, alanine, glutamine and histidine in PD, PSP and MSA were significantly (P < 0.001) higher than controls, whereas, glutamate and glucose were significantly increased in PD (P < 0.001), PSP and MSA (P < 0.05) vs., Control: Citrate was increased in PD, PSP and MSA (P < 0.05) vs., Control: While, acetone, lactate and formate were higher at P < 0.001, threonine is increased at P < 0.05. The 3D scattered score plot of OPLS-DA model revealed clear differentiation among the groups, R2 = 0.92 and Q2 = 0.78., Conclusion: Significant differences in various metabolite levels were found between control and disease groups. Common amino acids that are significantly higher in all groups include branched chain amino acids, which could increase neuronal excitability., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objective: Serum uric acid (UA) levels are reported to be decreased in patients with Parkinson's disease (PD) and multiple system atrophy (MSA). However, clinical correlates of serum UA levels are still unclear in PD-related disorders. We conducted a cross-sectional study to evaluate the associations between serum UA levels and disease duration, disease severity, and motor function among PD, MSA, and progressive supranuclear palsy (PSP) patients., Methods: A total of 100 patients with PD, 42 patients with MSA, 30 patients with PSP, and 100 controls were included in this study. Serum UA levels were determined, and associations among serum UA levels and disease duration, disease severity, and motor function in PD, PSP, and MSA patients were evaluated., Results: Serum UA levels were significantly lower in male PD, MSA, and PSP patients compared with the controls, but not in female patients. Serum UA levels were negatively correlated with disease duration and severity in MSA and PSP patients, but no correlations were observed in PD patients. The serum UA levels were significantly decreased in the tauopathy group (PSP patients) compared with the synucleinopathy group (PD and MSA patients) after adjusting for age, gender, and body mass index., Conclusion: We found decreased serum UA levels in male patients with PD-related disorders (PD, MSA, and PSP) compared with male controls, and significant correlations between serum UA levels and disease severity in MSA and PSP patients.

Introduction: Uric acid is a natural antioxidant, and it has been shown that low levels of uric acid could be a risk factor for the development of PD. Our aim was to investigate whether uric acid plays a role in PSP., Methods: We carried out a cross-sectional study to compare serum uric acid levels between PSP patients, PD patients, and healthy controls. We also analyzed longitudinal uric acid levels in the PSP group., Results: PSP patients showed reduced levels of serum uric acid as compared to healthy controls. This reduction was similar to that found in patients with PD. Uric acid levels of PSP patients did not change with time., Conclusion: Serum uric acid levels are reduced in PSP as well as in PD compared to healthy controls. Our data suggest that high levels of uric acid could be a natural protective factor against PSP., (© 2015 International Parkinson and Movement Disorder Society.)

Objective: Chronic inflammatory processes contribute to the eventual death of motor neurons and the development of symptoms in both idiopathic Parkinson disease (PD) and multiple system atrophy (MSA). Given the faster rate of progression and more severe symptoms associated with MSA, we hypothesized that markers of inflammation would be more evident in the peripheral blood of MSA than PD patients, and that evidence of this inflammation might assist early diagnosis of MSA versus PD., Methods: We performed multiplex analysis to determine the concentrations of 37 immune-associated cytokines and chemokines isolated from the plasma of patients with PD (n = 25) and MSA (n = 14) and compared our results to those of age-matched controls (n = 15). We then applied a mixed-effect multiple regression model to determine if the concentration of cytokines in the plasma of patients with PD and MSA changed significantly over time., Results: Patients with MSA had a trend towards overall lower levels of immune-associated cytokines, while serum cytokine levels were increased in patients with PD. Statistically adjusted comparisons of overall changes in cytokine concentrations between the PD and MSA groups revealed higher concentrations of T-cell-associated cytokines TNFβ and IL-7 in PD. Comparison of samples taken over time revealed significantly faster rates of change in 4 different cytokine concentrations (IL-4, IL-15, IL-2, and IL-9) in patients with MSA versus patients with PD., Conclusions: Our results suggest that single measurements of plasma concentrations of inflammation-associated cytokines cannot be used to distinguish disease states. However, measurements made over time may correlate with pathogenesis. The significant changes in T-cell-associated cytokines may shed light on immune mechanisms that contribute to PD and MSA disease progression., (© 2017 S. Karger AG, Basel.)

Background: Parkinson disease with orthostatic hypotension (PD + OH) and the parkinsonian form of multiple system atrophy (MSA-P) can be difficult to distinguish clinically. Recent studies indicate that PD entails a vesicular storage defect in catecholaminergic neurons. Although cardiac sympathetic neuroimaging by (18)F-dopamine positron emission tomography can identify decreased vesicular storage, this testing is not generally available. We assessed whether plasma biomarkers of a vesicular storage defect can separate PD + OH from MSA-P., Methods: We conceptualized that after F-dopamine injection, augmented production of F-dihydroxyphenylacetic acid (F-DOPAC) indicates decreased vesicular storage, and we therefore predicted that arterial plasma F-DOPAC would be elevated in PD + OH but not in MSA-P. We measured arterial plasma F-DOPAC after (18)F-dopamine administration (infused i.v. over 3 min) in patients with PD + OH (N = 12) or MSA-P (N = 21) and in healthy control subjects (N = 26). Peak F-DOPAC:dihydroxyphenylglycol (DHPG) was also calculated to adjust for effects of denervation on F-DOPAC production., Results: Plasma F-DOPAC accumulated rapidly after initiation of (18)F-dopamine infusion. Peak F-DOPAC (5-10 min) in PD + OH averaged three times that in MSA-P (P < 0.0001). Among MSA-P patients, none had peak F-DOPAC > 300 nCi-kg/cc-mCi, in contrast with 7 of 12 PD + OH patients (χ(2) = 16.6, P < 0.0001). DHPG was lower in PD + OH (3.83 ± 0.36 nmol/L) than in MSA-P (5.20 ± 0.29 nmol/L, P = 0.007). All MSA-P patients had peak F-DOPAC:DHPG < 60, in contrast with 9 of 12 PD + OH patients (χ(2) = 17.5, P < 0.0001). Adjustment of peak F-DOPAC for DHPG increased test sensitivity from 58 to 81% at similar high specificity., Interpretation: After F-dopamine injection, plasma F-DOPAC and F-DOPAC:DHPG distinguish PD + OH from MSA-P.

Background: Recently, increased serum insulin-like growth factor-1 (IGF-1) levels have been reported in patients with Parkinson's disease (PD) and multiple system atrophy (MSA)., Objective: To assess a correlation between the serum IGF-1 levels and clinical background factors in patients with PD and related disorders such as MSA and progressive supranuclear palsy (PSP)., Methods: A total of 79 PD patients, 25 MSA patients, 16 PSP patients and 52 healthy controls were included in this study. The serum IGF-1 and growth hormone (GH) levels were measured in a fasting state. Unified PD Rating Scale (UPDRS) part III was used to evaluate motor function. Unified MSA Rating Scale (UMSARS) part II was also employed for the MSA patients., Results: The serum IGF-1 levels were significantly increased in the MSA patients compared with the PD patients and controls. No significant differences were observed in the serum GH levels among the patients and controls. The serum IGF-1 levels of PD patients with Hoehn and Yahr stage 2 were significantly higher than those of patients with Hoehn and Yahr stages 3-5. In patients with PD and PSP, the serum IGF-1 levels were negatively correlated with UPDRS part III. In contrast, patients with MSA showed a positive correlation of the serum IGF-1 levels with disease duration, UPDRS part III and UMSARS part II., Conclusion: The difference in the serum IGF-1 level and its correlation with clinical variables among these disorders may reflect different ongoing disease processes in each disorder., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The arginine growth hormone (GH) stimulation test differentiates the Parkinsonian variant of multiple system atrophy (MSA-P) from idiopathic Parkinson's disease (PD). Our aim was to evaluate the accuracy of the arginine GH stimulation test in distinguishing between PSP, MSA-P, and PD. We measured the GH response to arginine in serum samples of 26 MSA-P, 23 PSP, and 26 PD patients, and in 80 healthy controls. We used ANOVA followed by the Bonferroni test to compare GH values and peaks among groups. We used receiver operating characteristic curve analysis to establish the arginine cut-off level that best differentiated between MSA-P, PSP, and PD. The GH peak was significantly lower (P < 0.01) in MSA-P (1.46 +/- 0.29 microg/L) than in both PD (8.74 +/- 0.98 microg/L) and PSP (6.64 +/- 0.82 microg/L) patients, and controls (8.59 +/- 0.44 microg/L). Growth hormone peaked later in PSP patients than in PD patients and controls. At a cut-off level of 4 microg/L, arginine test distinguished MSA-P from PD with a sensitivity of 92% and a specificity of 96%, and MSA-P from PSP with a sensitivity of 78% and a specificity of 96%. The GH response to arginine differentiates MSA-P from PD and PSP with a good diagnostic accuracy. The neuroendocrine response to arginine of PSP patients differed from that of MSA-P patients, but was not identical to that of normal controls and PD patients. Our results suggest that the impairment of the central mechanisms modulating GH release differs between PSP and MSA-P., (2007 Movement Disorder Society)

Idiopathic Parkinson's disease (IPD) is a common neurodegenerative disorder whose differential diagnosis from other forms of atypical parkinsonism, for instance multiple system atrophy (MSA) or progressive supranuclear palsy, may be difficult, especially in the early stages. Growth hormone stimulation tests have been recently reported to be useful in the differential diagnosis between IPD and MSA. Both clonidine, an alpha(2)-adrenoceptor agonist, and arginine, an amino acid activating the cholinergic system, have been used to assess growth hormone response in patients with IPD and MSA. This review summarizes the results of several studies and discusses the validity of these tests in the differential diagnosis of parkinsonisms.

alpha-Synuclein, a synaptic protein of unknown function, is a major component of Lewy bodies and may play a role in the pathophysiological process of Parkinson's disease (PD). In this study, we measured the plasma alpha-synuclein levels in 105 patients with PD, 38 patients with multiple system atrophy (MSA), and 51 age-matched controls. The alpha-synuclein level was significantly elevated in patients with PD (79.9 +/- 4.0 pg/ml, p < 0.001) and in those with MSA (78.1 +/- 3.5 pg/ml, p = 0.019) compared with the level in controls (76.1 +/- 3.9 pg/ml). The alpha-synuclein level was higher in patients with PD than in those with MSA (79.9 +/- 4.0 vs 78.1 +/- 3.5, p = 0.016). Our study demonstrated that the alpha-synuclein level in plasma is elevated in patients with PD and MSA.

Objective: Multiple system atrophy (MSA) is difficult to distinguish from idiopathic Parkinson's disease (PD) and idiopathic late-onset cerebellar ataxia (ILOCA). This study aimed to evaluate GH response to three different GH stimulation tests in order to establish a reliable test to differentiate these degenerative disorders., Design: Twelve patients with MSA, 10 with PD, eight with ILOCA and 30 healthy controls entered the study. They were submitted to clonidine, arginine, and GH-releasing-hormone (GHRH) + arginine tests in a random manner on three different nonconsecutive days. The peak serum GH response was used as a primary variable for analysis of stimulation tests. By ROC analysis, the optimum cut-off level was considered as the cut-off with the maximal sum of sensitivity and specificity., Results: After clonidine administration, GH peak was significantly lower in patients with MSA than in those with ILOCA (P < 0.05) and in the controls (P < 0.001). At the optimum cut-off level of 5 mU/l, the clonidine test distinguished patients with MSA from those with PD with a sensitivity and specificity of 78%. Moreover, this test distinguished patients with MSA from those with ILOCA with a sensitivity of 100% and a specificity of 75% at a cut-off level of 5 mU/l, and with a sensitivity of 75% and a specificity of 100% at the cut-off level of 7.6 mU/l. After arginine administration, the GH peak was significantly lower in patients with MSA than in those with ILOCA (P = 0.001) and in controls (P < 0.001). At the optimum cut-off level of 5 mU/l, the arginine test distinguished patients with MSA from those with PD with a sensitivity and a specificity of 100%. At a GH peak cut-off value of 3.6 mU/l the arginine test distinguished patients with MSA from those with ILOCA with a sensitivity and specificity of 100%. After GHRH + arginine administration, a significant GH increase was found in all groups of patients and controls., Conclusions: The GH response to arginine administration is impaired in MSA. Therefore, the arginine test showed the highest diagnostic accuracy to distinguish MSA from both PD and ILOCA, and could be used in the clinical practice of these neurodegenerative diseases.

The hypothalamic-pituitary axis (HPA) may be involved early in multiple system atrophy (MSA), whereas in idiopathic Parkinson's disease (IPD) its impairment seems to be correlated with motor disability. The release of prolactin (PRL) is mediated through the HPA and an increase in PRL levels is documented during stress. In this study, we investigated basal and erect PRL levels to assess whether basal PRL or changes in PRL levels after 60 degrees head-up tilt (HUT; orthostatic stress) could distinguish between MSA and IPD patients. We studied five patients with MSA on levodopa treatment, five levodopa-naive MSA patients, nine IPD patients on dopaminergic treatment, six drug-naive IPD patients and six normal individuals. PRL levels were measured in the supine position after 30 minutes rest and during 60 degrees HUT after 5 and 15 minutes. Baseline PRL values were significantly lower for patients with IPD than for those with MSA, both for levodopa-treated and naive patients ( p < 0.004, estimated decrease 55.1 %, 95 % CI from 29.4 % to 71.52 %). After orthostatic stress PRL levels were increased in healthy individuals after 15 minutes of HUT ( p = 0.044, estimated increase 11.5 %, 95 % CI from 0.4 % to 23.8 %), whereas there was no evidence for a change of PRL levels in patients with MSA or IPD after 5 and 15 minutes of HUT. We also did not find any evidence for a difference in PRL change after HUT between MSA and IPD patients. Baseline PRL levels might differentiate between early MSA and IPD, being higher in MSA. However, orthostatic stress using HUT appears unable to differentiate between MSA and IPD.

Clonidine has been proposed to differentiate multiple system atrophy (MSA) from idiopathic Parkinson's disease (IPD), as it does not increase growth hormone (GH) release in MSA. We studied GH release in response to clonidine in 7 IPD patients, 6 MSA patients, 4 patients affected by idiopathic late-onset cerebellar ataxia (ILOCA) and 8 healthy controls. In addition, we investigated the effects of GH releasing hormone plus arginine (GHRH-Arg) on GH release in the same patients. Both clonidine and GHRH-Arg raised serum GH levels in all groups examined. Clonidine failed to differentiate MSA from IPD and ILOCA. GHRH-Arg showed a lower increase of serum GH in MSA patients than in other groups, even if such difference was not statistically significant. We suggest that stimulation of GH release with GHRH-Arg rather than clonidine could differentiate MSA from IPD and ILOCA, but this hypothesis would need to be confirmed by further investigations.

Background: In Parkinson disease, orthostatic hypotension can result from L-dopa treatment or from sympathetic neurocirculatory failure. The latter is detected by abnormal blood pressure responses to the Valsalva maneuver and can be associated with loss of functional cardiac sympathetic nerve terminals., Objective: To determine the frequency of cardiac sympathetic denervation in Parkinson disease, with or without sympathetic neurocirculatory failure, and its association with disease duration, severity, and L-dopa treatment, Design: Intergroup comparisons in resting patients., Setting: National Institutes of Health Clinical Center, Bethesda, Maryland., Patients: 29 patients with Parkinson disease (9 with sympathetic neurocirculatory failure, 10 who had stopped receiving or had never been treated with L-dopa), 24 patients with multiple-system atrophy (17 with sympathetic neurocirculatory failure, 8 receiving L-dopa), 7 patients with pure autonomic failure, 33 controls with episodic or persistent orthostatic intolerance without sympathetic neurocirculatory failure, and 19 normal volunteers., Measurements: Beat-to-beat blood pressure responses to the Valsalva maneuver, interventricular septal 6-[18F]fluorodopamine-derived radioactivity, cardiac extraction fraction of [3H]norepinephrine, appearance rate of norepinephrine in coronary sinus plasma (cardiac norepinephrine spillover) and venous-arterial differences in levels of dihydroxyphenylglycol (DHPG) and endogenous L-dopa., Results: Of the 29 patients with Parkinson disease, 9 with sympathetic neurocirculatory failure and 11 without had low septal 6-[18F]fluorodopamine-derived radioactivity (2861 +/- 453 Bq/mL per MBq/kg and 5217 +/- 525 Bq/mL per MBq/kg, respectively). All 6 patients with Parkinson disease and decreased 6-[18F]fluorodopamine-derived radioactivity who underwent right-heart catheterization had a decreased cardiac extraction fraction of [3H]norepinephrine and virtually no cardiac norepinephrine spillover or venous-arterial increments in plasma levels of DHPG and L-dopa. Sympathetic neurocirculatory failure and decreased 6-[18F]fluorodopamine-derived radioactivity were unrelated to disease duration, disease severity, or L-dopa treatment, Conclusions: Many patients with Parkinson disease-including all those with sympathetic neurocirculatory failure-have evidence of cardiac sympathetic denervation. This suggests that loss of catecholamine innervation in Parkinson disease occurs in the nigrostriatal system in the brain and in the sympathetic nervous system in the heart

Hydroxyl radical (.OH) levels in blood, superoxide dismutase (SOD) activity in plasma (plasma-SOD) and in red blood cells (RBC) relative to Cu,Zn-SOD (SOD1) protein (RBC-SOD/SOD1), SOD1 protein in RBC (SOD1/RBC) and plasma (SOD1/plasma), and Mn-SOD protein in plasma (SOD2/plasma) were measured in patients with Parkinson's disease (PD), multiple-system atrophy (MSA) with parkinsonism, and in control subjects. Patients with PD had significantly higher.OH and plasma-SOD values and significantly lower RBC-SOD/SOD1 and SOD1/RBC values than the corresponding MSA and control values. In PD, RBC-SOD/SOD1 values were significantly lower in older patients and were negatively correlated with age.OH levels were significantly higher in PD patients with early onset, a long period of illness or severe Yahr stage, and were negatively correlated with onset and positively correlated with duration of illness. RBC-SOD/SOD1 values in PD patients who received pergolide therapy were significantly higher than those in PD patients who received neither pergolide nor bromocriptine therapy. Therefore, the higher.OH level and the lower SOD1 activity may play a role in the onset and progression of PD, and pergolide may act neuroprotectively by inducing SOD1 activity.

We analyzed the clinical and physiological features of autonomic failure with Parkinson's disease (AF-PD) in seven patients and compared them with those of autonomic failure with multiple system atrophy (AF-MSA). In AF-PD, parkinsonism was more gradually progressive than in AF-MSA, and symptoms were responsive to L-dopa. All seven patients with AF-PD had orthostatic hypotension, postprandial hypotension, and constipation, but no urinary retention. Of these, three had hypohidrosis and five had frequent urination; five patients had subnormal plasma norepinephrine (NE) concentrations. Supersensitivity to NE infusion was observed in all patients. Head-up tilting (HUT) test resulted in no increase of plasma NE concentrations in both groups, but a significant increase of the plasma arginine vasopressin (AVP) concentrations in the patients with AF-PD. Urodynamic studies revealed that urinary bladder function was relatively well preserved in AF-PD in contrast to AF-MSA. In conclusion, there exists some clinical and physiological differences in autonomic features between AF-PD and AF-MSA, and postganglionic involvement predominates in AF-PD.