Rationale and design of the PRAETORIAN-COVID trial: A double-blind, placebo-controlled randomized clinical trial with valsartan for PRevention of Acute rEspiraTORy dIstress syndrome in hospitAlized patieNts with SARS-COV-2 Infection Disease.

There is much debate on the use of angiotensin receptor blockers (ARBs) in severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2)-infected patients. Although it has been suggested that ARBs might lead to a higher susceptibility and severity of SARS-CoV-2 infection, experimental data suggest that ARBs may reduce acute lung injury via blocking angiotensin-II-mediated pulmonary permeability, inflammation, and fibrosis. However, despite these hypotheses, specific studies on ARBs in SARS-CoV-2 patients are lacking. METHODS: The PRAETORIAN-COVID trial is a multicenter, double-blind, placebo-controlled 1:1 randomized clinical trial in adult hospitalized SARS-CoV-2-infected patients (n = 651). The primary aim is to investigate the effect of the ARB valsartan compared to placebo on the composite end point of admission to an intensive care unit, mechanical ventilation, or death within 14 days of randomization. The active-treatment arm will receive valsartan in a dosage titrated to blood pressure up to a maximum of 160 mg bid, and the placebo arm will receive matching placebo. Treatment duration will be 14 days, or until the occurrence of the primary end point or until hospital discharge, if either of these occurs within 14 days. The trial is registered at clinicaltrials.gov (NCT04335786, 2020). SUMMARY: The PRAETORIAN-COVID trial is a double-blind, placebo-controlled 1:1 randomized trial to assess the effect of valsartan compared to placebo on the occurrence of ICU admission, mechanical ventilation, and death in hospitalized SARS-CoV-2-infected patients. The results of this study might impact the treatment of SARS-CoV-2 patients globally.

α-Synuclein real-time quaking-induced conversion in the cerebrospinal fluid of uncertain cases of parkinsonism.

A reliable biomarker is needed for accurate and early differentiation between Parkinson disease and the various forms of atypical parkinsonism. We used a novel real-time quaking-induced conversion (RT-QuIC) assay to detect α-synuclein (α-syn) aggregates in cerebrospinal fluid (CSF) of 118 patients with parkinsonism of uncertain clinical etiology and 52 controls. Diagnostic accuracy to distinguish α-synucleinopathies from non-α-synucleinopathies and controls was 84% (sensitivity = 75%, specificity = 94%, area under the curve = 0.84, 95% confidence interval = 0.78-0.91, p < 0.0001, positive predictive value = 93%). CSF α-syn RT-QuIC could be a useful diagnostic tool to help clinicians differentiate α-synucleinopathies from other forms of parkinsonism when the clinical picture is uncertain. Ann Neurol 2019;85:777-781.

Inflammation biomarker discovery in Parkinson's disease and atypical parkinsonisms.

BACKGROUND: Parkinson's disease (PD) and atypical parkinsonisms (APD) have overlapping symptoms challenging an early diagnosis. Diagnostic accuracy is important because PD and APD have different prognosis and response to treatment. We aimed to identify diagnostic inflammatory biomarkers of PD and APD in cerebrospinal fluid (CSF) using the multiplex proximity extension assay (PEA) technology and to study possible correlations of biomarkers with disease progression. METHODS: CSF from a longitudinal cohort study consisting of PD and APD patients (PD, n = 44; multiple system atrophy (MSA), n = 14; vascular parkinsonism (VaP), n = 9; and PD with VaP, n = 7) and controls (n = 25) were analyzed. RESULTS: Concentrations of CCL28 were elevated in PD compared to controls (p = 0.0001). Five other biomarkers differentiated both MSA and PD from controls (p < 0.05) and 10 biomarkers differentiated MSA from controls, of which two proteins, i.e. beta nerve growth factor (ß-NGF) and Delta and Notch like epidermal growth factor-related receptor (DNER), were also present at lower levels in MSA compared to PD (both p = 0.032). Two biomarkers (MCP-1 and MMP-10) positively correlated with PD progression (rho > 0.650; p < 0.01). CONCLUSIONS: PEA technique identified potential new CSF biomarkers to help to predict the prognosis of PD. Also, we identified new candidate biomarkers to distinguish MSA from PD.

Parkinson's Disease Diagnostic Observations (PADDO): study rationale and design of a prospective cohort study for early differentiation of parkinsonism.

BACKGROUND: Differentiation of Parkinson's disease (PD) from the various types of atypical parkinsonism (AP) such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB), corticobasal syndrome (CBS) and vascular parkinsonism (VP), can be challenging, especially early in the disease course when symptoms overlap. A major unmet need in the diagnostic workup of these disorders is a diagnostic tool that differentiates the various disorders, preferably in the earliest disease stages when the clinical presentation is similar. Many diagnostic tests have been evaluated, but their added value was studied mostly in retrospective case-control studies that included patients with a straightforward clinical diagnosis. Here, we describe the design of a prospective cohort study in patients with parkinsonism in an early disease stage who have an uncertain clinical diagnosis. Our aim is to evaluate the diagnostic accuracy of (1) detailed clinical examination by a movement disorder specialist, (2) magnetic resonance imaging (MRI) techniques and (3) cerebrospinal fluid (CSF) biomarkers. METHODS/DESIGN: Patients with parkinsonism with an uncertain clinical diagnosis and a disease course less than three years will be recruited. Patients will undergo extensive neurological examination, brain MRI including conventional and advanced sequences, and a lumbar puncture. The diagnosis (including level of certainty) will be defined by a movement disorders expert, neuroradiologist and neurochemist based on clinical data, MRI results and CSF results, respectively. The clinical diagnosis after three years' follow-up will serve as the "gold standard" reference diagnosis, based on consensus criteria and as established by two movement disorder specialists (blinded to the test results). Diagnostic accuracy of individual instruments and added value of brain MRI and CSF analysis after evaluation by a movement disorder expert will be calculated, expressed as the change in percentage of individuals that are correctly diagnosed with PD or AP. DISCUSSION: This study will yield new insights into the diagnostic value of clinical evaluation by a movement disorder specialist, brain MRI and CSF analysis in discriminating PD from AP in early disease stages. The outcome has the potential to help clinicians in choosing the optimal diagnostic strategy for patients with an uncertain clinical diagnosis. TRIAL REGISTRATION: NCT01249768, registered November 26 2010.

Nigrosome-1 on Susceptibility Weighted Imaging to Differentiate Parkinson's Disease From Atypical Parkinsonism: An In Vivo and Ex Vivo Pilot Study.

BACKGROUND: Previous case-control studies have suggested that the absence of a swallow-tail appearance in the substantia nigra on high-resolution SWI, representing nigrosome-1, has high accuracy to identify Parkinson's disease (PD). The first goal of our study was to evaluate nigrosome-1 ex vivo using optimized high-resolution susceptibility sensitive MRI. Our second goal was to evaluate its diagnostic value in vivo using a clinical 3T SWI sequence to differentiate between PD and atypical parkinsonism (AP) in a cohort of patients with early-stage parkinsonism. MATERIAL/METHODS: Case-control pilot study to evaluate nigrosome-1 ex vivo (2 PD, 2 controls), using high-resolution susceptibility sensitive sequences at 11.7 T MRI. Next, evaluation of nigrosome-1 in vivo using a clinical 3 T SWI sequence in a prospective cohort of 60 patients with early-stage parkinsonism (39 PD, 21 AP). Moreover, 12 control subjects were scanned. The bilateral substantia nigra was evaluated by two neuroradiologists for the presence, absence or indecisive presence of nigrosome-1. The discriminative power was evaluated by Receiver-Operating Characteristic. RESULTS: We identified nigrosome-1 in ex vivo control subjects. Nigrosome-1 was not identified in the ex vivo PD cases. In our prospective clinical cohort study, the AUC for the swallow-tail sign to discriminate between PD and AP was 0.56 (0.41-0.71) for reader 1 and 0.68 (0.55-0.82) for reader 2. CONCLUSIONS: The diagnostic accuracy of the swallow-tail sign was marginal to discriminate between PD and AP using our clinical 3 T SWI sequence.

Conventional 3T brain MRI and diffusion tensor imaging in the diagnostic workup of early stage parkinsonism.

INTRODUCTION: The aim of this study is to evaluate whether the diagnostic accuracy of 3 T brain MRI is improved by region of interest (ROI) measures of diffusion tensor imaging (DTI), to differentiate between neurodegenerative atypical parkinsonism (AP) and Parkinson's disease (PD) in early stage parkinsonism. METHODS: We performed a prospective observational cohort study of 60 patients presenting with early stage parkinsonism and initial uncertain diagnosis. At baseline, patients underwent a 3 T brain MRI including DTI. After clinical follow-up (mean 28.3 months), diagnoses could be made in 49 patients (30 PD and 19 AP). Conventional brain MRI was evaluated for regions of atrophy and signal intensity changes. Tract-based spatial statistics and ROI analyses of DTI were performed to analyze group differences in mean diffusivity (MD) and fractional anisotropy (FA), and diagnostic thresholds were determined. Diagnostic accuracy of conventional brain MRI and DTI was assessed with the receiver operating characteristic (ROC). RESULTS: Significantly higher MD of the centrum semiovale, body corpus callosum, putamen, external capsule, midbrain, superior cerebellum, and superior cerebellar peduncles was found in AP. Significantly increased MD of the putamen was found in multiple system atrophy-parkinsonian form (MSA-P) and increased MD in the midbrain and superior cerebellar peduncles in progressive supranuclear palsy (PSP). The diagnostic accuracy of brain MRI to identify AP as a group was not improved by ROI measures of MD, though the diagnostic accuracy to identify MSA-P was slightly increased (AUC 0.82 to 0.85). CONCLUSION: The diagnostic accuracy of brain MRI to identify AP as a group was not improved by the current analysis approach to DTI, though DTI measures could be of added value to identify AP subgroups.

Factors associated with mortality in early stages of parkinsonism.

Prognosis of patients with parkinsonism varies greatly between the various parkinsonian syndromes. However, it is often difficult to distinguish the different forms, particularly in early stages. We examined predictors of mortality and functional outcome in patients with recent-onset parkinsonism with an initially uncertain diagnosis (n = 156). Patients were recruited between 2003 and 2006, comprehensively investigated, and followed prospectively (up to 15 years, mean 7 years). A final clinical diagnosis was established after follow-up. Independent predictors of mortality were investigated with multivariable Cox regression and combined into a simple prediction model. Model performance to predict 5- and 10-year mortality and functional outcome after 3 years was evaluated and externally validated in a second cohort of 62 patients with parkinsonism with an initially uncertain diagnosis. Ninety-one patients died (58%). Orthostatic hypotension, impaired cognition, abnormal tandem gait, and elevated neurofilament light chain concentration in serum or CSF were associated with mortality. A simple model that combined these factors showed excellent performance for prediction of functional outcome after 3 years and mortality after 5 and 10 years (c-statistic ~0.90 for all models). Model performance was confirmed after external validation: prediction of functional outcome after 3 years (c-statistic 0.89, 95% CI 0.80-0.98) and mortality after 5 years (c-statistic 0.91, 95% CI 0.84-0.99) were comparable to the results in the discovery cohort. These findings help clinicians to estimate a patient's prognosis, irrespective of the specific diagnosis.

Peripheral decarboxylase inhibitors paradoxically induce aromatic L-amino acid decarboxylase.

Peripheral decarboxylase inhibitors (PDIs) prevent conversion of levodopa to dopamine in the blood by the enzyme aromatic L-amino acid decarboxylase (AADC). Alterations in enzyme activity may contribute to the required higher dosages of levodopa observed in many patients with Parkinson's disease. We evaluated the effect of levodopa/PDI use on serum AADC enzyme activity. Serum AADC enzyme activity was evaluated in three independent cohorts of patients with Parkinson's disease or parkinsonism (n = 301) and compared between patients on levodopa/PDI vs. patients not on this medication. AADC enzyme activity was elevated in 62% of patients on levodopa/PDI treatment, compared to 19% of patients not on levodopa/PDI (median 90 mU/L vs. 50 mU/L, p < 0.001). Patients with elevated AADC activity had longer disease duration and higher doses of levodopa/PDI. These findings may implicate that peripheral AADC induction could underlie a waning effect of levodopa, necessitating dose increases to maintain a sustained therapeutic effect.

Identification of cerebrospinal fluid biomarkers for parkinsonism using a proteomics approach.

The aim of our study was to investigate cerebrospinal fluid (CSF) tryptic peptide profiles as potential diagnostic biomarkers for the discrimination of parkinsonian disorders. CSF samples were collected from individuals with parkinsonism, who had an uncertain diagnosis at the time of inclusion and who were followed for up to 12 years in a longitudinal study. We performed shotgun proteomics to identify tryptic peptides in CSF of Parkinson's disease (PD, n = 10), multiple system atrophy patients (MSA, n = 5) and non-neurological controls (n = 10). We validated tryptic peptides with differential levels between PD and MSA using a newly developed selected reaction monitoring (SRM) assay in CSF of PD (n = 46), atypical parkinsonism patients (AP; MSA, n = 17; Progressive supranuclear palsy; n = 8) and non-neurological controls (n = 39). We identified 191 tryptic peptides that differed significantly between PD and MSA, of which 34 met our criteria for SRM development. For 14/34 peptides we confirmed differences between PD and AP. These tryptic peptides discriminated PD from AP with moderate-to-high accuracy. Random forest modelling including tryptic peptides plus either clinical assessments or other CSF parameters (neurofilament light chain, phosphorylated tau protein) and age improved the discrimination of PD vs. AP. Our results show that the discovery of tryptic peptides by untargeted and subsequent validation by targeted proteomics is a suitable strategy to identify potential CSF biomarkers for PD versus AP. Furthermore, the tryptic peptides, and corresponding proteins, that we identified as differential biomarkers may increase our current knowledge about the disease-specific pathophysiological mechanisms of parkinsonism.

Cerebrospinal fluid myelin basic protein is elevated in multiple system atrophy.

INTRODUCTION: Parkinson's disease (PD) and multiple system atrophy (MSA) have overlapping symptoms, challenging an early diagnosis. Diagnostic accuracy is important because PD and MSA have a different prognosis and response to treatment. Here, we aimed to evaluate the diagnostic value of brain-specific structural proteins in cerebrospinal fluid (CSF) of PD and MSA patients, as well as their association with cognitive decline. METHODS: CSF samples were collected from patients with clear signs of parkinsonism, but with uncertain diagnosis at the time of inclusion. Clinical diagnoses of PD (n = 55) and MSA (n = 22) were established after 3 and 10 years of follow-up and re-evaluated after 12 years, according to the most updated clinical criteria. CSF from controls (n = 118) was studied for comparison. Neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP), S100 calcium-binding protein B (S100B) and myelin basic protein (MBP) levels in CSF were measured using ELISA. Protein levels were also correlated with cognitive decline, i.e. worsening of the mini mental state examination (MMSE) over a period of three years. RESULTS: MBP concentrations were increased in MSA compared to PD and controls (p < 0.005) and could differentiate MSA and PD with high accuracy (AUC = 0.781; p < 0.001). Concentrations of MPB, GFAP and S100B, but not NSE, were significantly elevated in PD patients compared to controls (p = 0.05). None of the brain-specific structural proteins correlated with MMSE progression. CONCLUSIONS: Our results demonstrate that MBP differentiates PD from MSA at early stages of the disease, indicating that demyelination and axonal damage may already occur in early stages of MSA.

Cerebrospinal fluid monocyte chemoattractant protein 1 correlates with progression of Parkinson's disease.

Parkinson's disease (PD) and multiple system atrophy (MSA) have overlapping symptoms, challenging a correct early diagnosis. Prognostic information is needed to predict disease progression and provide appropriate counseling. Neuroinflammation plays a role in the pathology of both disorders, as shown in genetic and postmortem tissue studies. Monocyte chemoattractant protein 1 (MCP-1) and neuroleukin (NLK) are two inflammatory proteins with potential to serve as biomarkers of the neuroinflammatory process. Here, we aimed to study the biomarker potential of both MCP-1 and NLK protein levels in cerebrospinal fluid (CSF) from a longitudinal cohort study (Radboudumc, Nijmegen, The Netherlands), consisting of PD patients (n = 46), MSA patients (n = 17) and control subjects (n = 52) using ELISA. We also correlated MCP-1 and NLK levels in CSF to several parameters of disease. We showed that MCP-1 levels in CSF positively correlate with PD progression (ρ = 0.363; p = 0.017) but could not differentiate between PD, MSA, and controls. NLK levels in CSF neither differentiated between PD, MSA, and controls, nor correlated with disease progression. Our results indicate that MCP-1 levels in CSF cannot distinguish between PD, MSA, and controls but correlate with disease progression in PD patients, suggesting that neuroinflammation is associated with clinical progression in PD. The correlation with disease progression was only moderate, so MCP-1 levels in CSF should be included in a larger battery of prognostic biomarkers that also tackle different pathophysiological processes.

Serum NFL discriminates Parkinson disease from atypical parkinsonisms.

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.

Cerebrospinal Fluid Galectin-1 Levels Discriminate Patients with Parkinsonism from Controls.

Parkinson's disease (PD) is the second most common neurodegenerative disorder in elderly people. Currently, the diagnosis of PD is based on neurological examination, neuroimaging, and the response to dopaminergic medication. The diagnosis can be challenging, especially at early disease stages, when the symptoms of patients with atypical parkinsonism (APD) may strongly overlap. Therefore, reliable biomarkers that are able to identify patients with PD are much needed. Here, we aimed to identify and validate new biomarkers for PD in cerebrospinal fluid (CSF). We performed a profiling experiment using mass spectrometry (MS) of CSF from ten PD patients and ten matched non-neurological controls. We selected one protein, galectin-1 (Gal-1), which was differentially expressed in PD vs. controls, and quantified its concentrations in CSF by enzyme-linked immunosorbent assay (ELISA) in three new cohorts of 37 PD patients, 21 APD patients, and 44 controls. CSF levels of Gal-1 were lower in PD in both the discovery and validation experiments and discriminated PD from controls with moderate-high accuracy levels (ELISA: area under the curve = 0.7). Similar levels of Gal-1 were found in PD and APD. Gal-1 levels were correlated to age in all groups and correlated in the PD patients to CSF levels of total tau, phosphorylated tau, neurofilament light chain (NFL), and the mini-mental state examination (MMSE) score. We conclude that MS profiling of proteins may be a useful tool to identify novel biomarkers of neurological diseases and that CSF Gal-1 levels may discriminate PD from non-neurological controls.

Clinical correlates of cerebral white matter abnormalities in patients with Parkinson's disease.

OBJECTIVE: To determine if autonomic dysfunction, cognitive disorders or axial disability are associated with white matter lesions (WML) in Parkinson disease (PD). METHODS: We performed a retrospective cross-sectional review study on 204 consecutive PD patients who underwent cerebral MRI in our center between January 2012 and July 2016. For each patient, we scored the severity of WML and PV (periventricular) WML using the Fazekas score and using the ARWMC scale for WML and BG (basal ganglia) and clinical characteristics such as neurogenic orthostatic hypotension and cognitive function. RESULTS: 204 PD patients were included of whom n = 53 (26.0%) had neurogenic orthostatic hypotension (nOH). The presence of nOH was significantly associated with the severity of WML as defined by the Fazekas score and the ARWMC scale. An ordinal regression model confirmed this association with an OR of 0.41 (95% CI 0.18-0.92: p = .03) and an OR of 0.39 (95% CI 0.17-0.88: p = .02). There were no significant associations between WML and other co-variables, including hypertension, dopaminergic medication use, Hoehn and Yahr stage, gender and cognitive decline. CONCLUSION: The presence of nOH is associated with WML severity in PD patients.

Pulsatile Proptosis due to Intraorbital Meningocele.

We present a case of a 79-year-old man with a non-symptomatic pulsatile proptosis of the left eye. Magnetic resonance imaging revealed a meningocele into the left orbit due to an osseous defect in the orbital roof.

Biomarkers in cerebrospinal fluid for synucleinopathies, tauopathies, and other neurodegenerative disorders.

The incidence of neurodegenerative disorders is increasing due to worldwide population aging. In general, sporadic forms account for 90% of total cases with neurodegenerative disorders and the reasons underlying initiation or progression of these diseases remain unknown for almost all disorders. To date, diagnosis is mainly based on clinical symptoms and neuroimaging, which is in many cases insufficient due to overlap in clinical symptoms among several neurodegenerative disorders. Therefore, postmortem neuropathologic confirmation remains the gold-standard diagnostic technique for many disorders. Biomarkers that could help in defining the clinical diagnosis, or predict disease progression and response to treatment, would therefore be very useful. In this chapter, we discuss potential biomarkers in cerebrospinal fluid studied in synucleinopathies, tauopathies, and other neurodegenerative disorders, and their possible application for clinical practice. Dementias are excluded in this analysis as these are discussed in Chapter 6.

MicroRNAs in Cerebrospinal Fluid as Potential Biomarkers for Parkinson's Disease and Multiple System Atrophy.

Parkinson's disease (PD) and multiple system atrophy (MSA) are both part of the spectrum of neurodegenerative movement disorders and α-synucleinopathies with overlap of symptoms especially at early stages of the disease but with distinct disease progression and responses to dopaminergic treatment. Therefore, having biomarkers that specifically classify patients, which could discriminate PD from MSA, would be very useful. MicroRNAs (miRNAs) regulate protein translation and are observed in biological fluids, including cerebrospinal fluid (CSF), and may therefore have potential as biomarkers of disease. The aim of our study was to determine if miRNAs in CSF could be used as biomarkers for either PD or MSA. Using quantitative PCR (qPCR), we evaluated expression levels of 10 miRNAs in CSF patient samples from PD (n = 28), MSA (n = 17), and non-neurological controls (n = 28). We identified two miRNAs (miR-24 and miR-205) that distinguished PD from controls and four miRNAs that differentiated MSA from controls (miR-19a, miR-19b, miR-24, and miR-34c). Combinations of miRNAs accurately discriminated either PD (area under the curve (AUC) = 0.96) or MSA (AUC = 0.86) from controls. In MSA, we also observed that miR-24 and miR-148b correlated with cerebellar ataxia symptoms, suggesting that these miRNAs are involved in cerebellar degeneration in MSA. Our findings support the potential of miRNA panels as biomarkers for movement disorders and may provide more insights into the pathological mechanisms related to these disorders.