CSF biomarkers and clinical progression of Parkinson disease

Objective: To investigate whether certain CSF biomarkers at baseline can predict future progression of motor symptoms and cognitive decline in patients with Parkinson disease (PD).

Methods: Patients and controls were recruited from hospitals in southern Sweden as part of the prospective and longitudinal Swedish BioFinder Study. In the present study, we included 42 patients with PD and 69 controls who had clinical assessment and lumbar puncture at baseline. Baseline CSF samples were analyzed for α-synuclein (αSyn), β-amyloid 1–42 (Aβ₄₂), tau, phosphorylated tau, and neurofilament light. Associations between CSF markers at baseline and change in clinical characteristics after 2 years of follow-up were investigated using multivariate models adjusting for age, sex, disease duration, and levodopa-equivalent daily dose.

Results: Higher levels of αSyn within the PD group were associated with progression of motor symptoms and cognitive decline over 2 years, indicated by significant relationships between αSyn and change in Hoehn and Yahr (β = 0.394, p = 0.043), Unified Parkinson's Disease Rating Scale, Part III (UPDRS-III) (β = 0.449, p = 0.013), Timed Up and Go (β = 0.406, p = 0.023), and A Quick Test of Cognitive Speed (β = 0.423, p = 0.018). Lower levels of Aβ₄₂ were associated with worsening of performance on delayed memory recall (F = 5.834, p = 0.022). Finally, high levels of phosphorylated tau were associated with worsening in motor symptoms (UPDRS-III, β = 0.350, p = 0.045; Hoehn and Yahr, β = 0.366, p = 0.038).

Conclusion: We found evidence of a link between higher levels of αSyn at baseline and worsening of motor symptoms and cognitive speed over 2 years in PD. Increased αSyn might be a marker of more intense synaptic degeneration in PD. The results indicate that cortical amyloid pathology (low CSF Aβ₄₂) is associated with memory decline.

Neurology 2014

Topography and associations of perivascular spaces in healthy adults The Kashima Scan Study

ABSTRACT

Objective: We investigated whether the topography of MRI-visible perivascular spaces (PVS) is associated with markers of specific underlying small vessel disease, including cerebral microbleed (CMB) distribution, in neurologically healthy adults.

Methods: We analyzed baseline data of an ongoing Japanese population-based cohort study. PVS were rated in the basal ganglia (BG-PVS) and centrum semiovale (CSO-PVS) on axial T2-weighted MRI using a validated rating scale (score 0–4). BG-PVS degree was classified as low (score <2) or high (score ≥2). CSO-PVS degree was classified as low (score <3) or high (score ≥3). Independent demographic, clinical, and imaging factors for high degree of BG-PVS and CSO-PVS were investigated.

Results: A total of 1,575 neurologically healthy adults were included (mean age 57.1 years, SD 9.7; 47% male). In multivariable analyses, high degree of BG-PVS (n = 212, 14%) was associated with deep or infratentorial CMBs (odds ratio [OR] 2.77, 95% confidence interval [CI] 1.62–4.74), a marker of hypertensive arteriopathy; by contrast, high degree of CSO-PVS (n = 357, 23%) was associated with strictly lobar CMBs (OR 2.49, 95% CI 1.35–4.61), which share risk factors with cerebral amyloid angiopathy. Both high degree of BG-PVS and CSO-PVS were associated with hypertension (OR 2.03, 95% CI 1.46–2.82 and OR 1.39, 95% CI 1.07–1.81, respectively), lacunes (OR 3.35, 95% CI 1.92–5.86; OR 1.83 95% CI 1.08–3.08), and severe white matter hyperintensities (OR 2.17, 95% CI 1.42–3.31; OR 1.35, 95% CI 0.93–1.96), but these associations were stronger for high degree of BG-PVS.

Conclusions: In a neurologically healthy cohort, the associations of PVS differ according to their topography. PVS distribution may be useful for the early detection and classification of small vessel disease.

Neurology 2014

'The clocks that time us'—circadian rhythms in neurodegenerative disorders

Circadian rhythms are physiological and behavioural cycles generated by an endogenous biological clock, the suprachiasmatic nucleus. The circadian system influences the majority of physiological processes, including sleep–wake homeostasis. Impaired sleep and alertness are common symptoms of neurodegenerative disorders, and circadian dysfunction might exacerbate the disease process. The pathophysiology of sleep–wake disturbances in these disorders remains largely unknown, and is presumably multifactorial. Circadian rhythm dysfunction is often observed in patients with Alzheimer disease, in whom it has a major impact on quality of life and represents one of the most important factors leading to institutionalization of patients. Similarly, sleep and circadian problems represent common nonmotor features of Parkinson disease and Huntington disease. Clinical studies and experiments in animal models of neurodegenerative disorders have revealed the progressive nature of circadian dysfunction throughout the course of neurodegeneration, and suggest strategies for the restoration of circadian rhythmicity involving behavioural and pharmacological interventions that target the sleep–wake cycle. In this Review, we discuss the role of the circadian system in the regulation of the sleep–wake cycle, and outline the implications of disrupted circadian timekeeping in neurodegenerative diseases.

Nature Reviews Neurology 2014

Neuroimaging in Parkinson disease: from research setting to clinical practice

Over the past three decades, neuroimaging studies—including structural, functional and molecular modalities—have provided invaluable insights into the mechanisms underlying Parkinson disease (PD). Observations from multimodal neuroimaging techniques have indicated changes in brain structure and metabolic activity, and an array of neurochemical changes that affect receptor sites and neurotransmitter systems. Characterization of the neurobiological alterations that lead to phenotypic heterogeneity in patients with PD has considerably aided the in vivo investigation of aetiology and pathophysiology, and the identification of novel targets for pharmacological or surgical treatments, including cell therapy. Although PD is now considered to be very complex, no neuroimaging modalities are specifically recommended for routine use in clinical practice. However, conventional MRI and dopamine transporter imaging are commonly used as adjuvant tools in the differential diagnosis between PD and nondegenerative causes of parkinsonism. First-line neuroimaging tools that could have an impact on patient prognosis and treatment strategies remain elusive. This Review discusses the lessons learnt from decades of neuroimaging research in PD, and the promising new approaches with potential applicability to clinical practice.

Nature Reviews Neurology 2014

Neuroimmunology: Towards more-accurate diagnosis in neuromyelitis optica

Neuromyelitis optica spectrum disorders (NMOSD) can mimic multiple sclerosis (MS). Avoiding misdiagnosis is crucial, because some disease-modifying drugs for MS can aggravate NMOSD, causing blindness and paraplegia. A recent study reports that misdiagnosis of NMOSD as MS occasionally occurs, and that a two-step antibody assay could improve differential diagnosis.

Nature Reviews Neurology 2014

Safety, tolerability, and efficacy of PBT2 in Huntington's disease: a phase 2, randomised, double-blind, placebo-controlled trial

PBT2 is a metal protein-attenuating compound that might reduce metal-induced aggregation of mutant huntingtin and has prolonged survival in a mouse model of Huntington's disease. We aimed to assess the safety, tolerability, and efficacy of PBT2 in patients with Huntington's disease.

Methods

In this 26-week, randomised, double-blind, placebo-controlled trial, adults (≥25 years old) with early-stage to mid-stage Huntington's disease were randomly assigned (1:1:1) by a centralised interactive response system to once daily PBT2 250 mg, PBT2 100 mg, or placebo. Randomisation was stratified by site with a block size of three. Participants, carers, the steering committee, site investigators, study staff, and the study sponsor were masked to treatment assignment. Primary endpoints were safety and tolerability. The safety population consisted of all participants who were randomly assigned and had at least one dose of study drug. The principal secondary endpoint was cognition, measured by the change from baseline to week 26 in the main composite Z score of five cognitive tests (Category Fluency Test, Trail Making Test Part B, Map Search, Symbol Digit Modalities Test, and Stroop Word Reading Test) and scores on eight individual cognitive tests (the five aforementioned plus the Trail Making Test Part A, Montreal Cognitive Assessment, and the Speeded Tapping Test). The intention-to-treat population comprised participants who were randomly assigned and had at least one efficacy assessment after administration of study drug. This trial is registered with ClinicalTrials.gov, NCT01590888.

Findings

Between April 18, 2012, and Dec 14, 2012, 109 participants were randomly assigned to PBT2 250 mg (n=36), PBT2 100 mg (n=38), or placebo (n=35) at 19 research centres in Australia and the USA. 32 (89%) individuals on PBT2 250 mg, 38 (100%) on PBT2 100 mg, and 34 (97%) on placebo completed the study. Six serious adverse events (acute coronary syndrome, major depression, pneumonia, suicide attempt, viral infection, and worsening of Huntington's disease) occurred in five participants in the PBT2 250 mg group, three (fall with subdural haematoma, suicide attempt, and hospital admission for stabilisation of Huntington's disease) occurred in two participants in the PBT2 100 mg group, and one (increasing aggression) occurred in a participant in the placebo group. The site investigators deemed all, except the worsening of Huntington's disease, as unrelated to study drug. 32 (89%) participants on PBT2 250 mg, 30 (79%) on PBT2 100 mg, and 28 (80%) on placebo had at least one adverse event. Compared with placebo, neither PBT2 100 mg (least-squares mean 0·02, 95% CI −0·10 to 0·14; p=0·772) nor PBT2 250 mg (0·07, −0·05 to 0·20; p=0·240) significantly improved the main composite cognition Z score between baseline and 26 weeks. Compared with placebo, the Trail Making Test Part B score was improved between baseline and 26 weeks in the PBT2 250 mg group (17·65 s, 0·65—34·65; p=0·042) but not in the 100 mg group (0·79 s improvement, −15·75 to 17·32; p=0·925); neither dose significantly improved cognition on the other tests.

Interpretation

PBT2 was generally safe and well tolerated in patients with Huntington's disease. The potential benefit on executive function will need to be confirmed in a larger study.

Lancet Neurology 2014

Angiotensin-Converting Enzyme Inhibitors and Amyotrophic Lateral Sclerosis Risk A Total Population–Based Case-Control Study

Importance  Although several studies have shown that use of angiotensin-converting enzyme inhibitors (ACEIs) potentially decreased amyotrophic lateral sclerosis (ALS) risk in animal models, to our knowledge, there has been no human study in the literature discussing this issue.

Objective  To investigate the association between the use of ACEIs and the risk for developing ALS.

Design, Setting, and Participants  This case-control study was conducted using the total population of Taiwanese citizens seen in general medical practice; therefore, the findings can be applied to the general population. The case group comprised 729 patients with newly diagnosed ALS and a severely disabling disease certificate between January 1, 2002, and December 31, 2008. These cases were compared with 14 580 sex-, age-, residence-, and insurance premium–matched control individuals.

Exposures  Use of ACEIs was analyzed using a conditional logistic regression model that controlled for other antihypertensives, aspirin, steroids, nonsteroidal anti-inflammatory drugs, Charlson Comorbidity Index score, length of hospital stay, and number of outpatient visits. The cumulative defined daily dose (cDDD), which indicates the exposed duration of drug use, was estimated as the sum of dispensed DDD of drug and compared with the risk for ALS.

Main Outcomes and Measures  All patients with ALS fulfilled El Escorial criteria in this study. Medical claim data past 1 to 5 years of ALS first diagnosis date for patients and claim data from their matched control individuals were included in the analysis.

Results  There was a dose-dependent inverse association between ACEI use and the risk for developing ALS. When compared with patients who did not use ACEIs, the adjusted odds ratios were 0.83 (95% CI, 0.65-1.07; P = .15) for the group prescribed ACEIs lower than 449.5 of the cDDD and 0.43 cDDD (95% CI, 0.26-0.72; P = .001) for the group with a cumulative ACEI use of greater than 449.5 cDDD. The association was most predominant in men older than 55 years.

Conclusions and Relevance  Use of ACEIs exhibited a dose-dependent inverse association with ALS. This study demonstrated a 57% risk reduction in the chance for developing ALS in people who used ACEIs greater than 449.5 cDDD in 4 years.

JAMA Neurology 2014