Pathogenesis of Parkinson Disease-the gut-brain axis and enviromental factors

Parkinson disease (PD) follows a defined clinical pattern, and a range of nonmotor symptoms precede the motor phase. The predominant early nonmotor manifestations are olfactory impairment and constipation. The pathology that accompanies these symptoms is consistent with the Braak staging system: α-synuclein in the dorsal motor nucleus of the vagus nerve, the olfactory bulb, the enteric nervous system (ENS) and the submandibular gland, each of which is a gateway to the environment. The neuropathological process that leads to PD seems to start in the ENS or the olfactory bulb and spreads via rostrocranial transmission to the substantia nigra and further into the CNS, raising the intriguing possibility that environmental substances can trigger pathogenesis. Evidence from epidemiological studies and animal models supports this hypothesis. For example, in mice, intragastric administration of the pesticide rotenone can almost completely reproduce the typical pathological and clinical features of PD. In this Review, we present clinical and pathological evidence to support the hypothesis that PD starts in the gut and spreads via trans-synaptic cell-to-cell transfer of pathology through the sympathetic and parasympathetic nervous systems to the substantia nigra and the CNS. We also consider how environmental factors might trigger pathogenesis, and the potential for therapeutically targeting the mechanisms of these initial stages.

Nature Reviews Neurology 2015

Treatment and Outcome of Thrombolysis-Related Hemorrhage A Multicenter Retrospective Study

Importance  Treatments for symptomatic intracerebral hemorrhage (sICH) are based on expert opinion, with limited data available on efficacy.

Objective  To better understand the natural history of thrombolysis-related sICH, with a focus on the efficacy of various treatments used.

Design, Setting, and Participants  Multicenter retrospective study between January 1, 2009, and April 30, 2014, at 10 primary and comprehensive stroke centers across the United States. Participants were all patients with sICH, using the definition by the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST), which included a parenchymal hematoma type 2 and at least a 4-point increase in the National Institutes of Health Stroke Scale score.

Main Outcomes and Measures  The primary outcome was in-hospital mortality, and the secondary outcome was hematoma expansion, defined as a 33% increase in the hematoma volume on follow-up imaging.

Results  Of 3894 patients treated with intravenous recombinant tissue plasminogen activator (rtPA) within 4½ hours after symptom onset of ischemic stroke, 128 (3.3%) had sICH. The median time from initiation of rtPA therapy to sICH diagnosis was 470 minutes (range, 30-2572 minutes), and the median time from diagnosis to treatment of sICH was 112 minutes (range, 12-628 minutes). The in-hospital mortality rate was 52.3% (67 of 128), and 26.8% (22 of 82) had hematoma expansion. In the multivariable models, code status change to comfort measures after sICH diagnosis was the sole factor associated with increased in-hospital mortality (odds ratio, 3.6; 95% CI, 1.2-10.6). Severe hypofibrinogenemia (fibrinogen level, <150 mg/dL) was associated with hematoma expansion, occurring in 36.3% (8 of 22) of patients without hematoma expansion vs in 25.0% (15 of 60) of patients with hematoma expansion (P = .01), highlighting a role for cryoprecipitate in reversing rtPA coagulopathy.

Conclusions and Relevance  In this study, treatment of postthrombolysis sICH did not significantly reduce the likelihood of in-hospital mortality or hematoma expansion. Shortening the time to diagnosis and treatment may be a key variable in improving outcomes of patients with sICH.

JAMA Neurology 2015

Progression in Behavioral Variant Frontotemporal Dementia A Longitudinal Study

Importance  A gap in the literature exists regarding progression in behavioral variant frontotemporal dementia (BVFTD). Guidance is needed concerning markers that will enable clinicians to discriminate FTD more effectively from phenocopies and to identify factors that determine progression and thereby prognosis.

Objectives  To observe longitudinal outcomes and progression in probable and possible BVFTD in accordance with international diagnostic criteria and to identify features that may aid clinicians to prognosticate better in cases of possible BVFTD.

Design, Setting, and Participants  Longitudinal cohort study performed in a specialist tertiary FTD research clinic. Fifty-eight consecutive patients were followed up longitudinally from January 1, 2008, through December 31, 2013, and classified as having possible, probable, or definite BVFTD at presentation and latest review. Final follow-up was completed on December 31, 2013, and data were analyzed from January 1 to August 1, 2014.

Main Outcomes and Measures  Clinical, pathological, genetic, neuropsychological, and neuroimaging data were analyzed to categorize patients, to compare differences between groups with changed and unchanged diagnoses, to determine rates of progression in BVFTD, and to identify prognostic features in possible BVFTD.

Results  At presentation, 38 of the 58 patients fulfilled criteria for probable BVFTD; of these, 36 continued to satisfy probable criteria or underwent conversion to definite criteria over time. The remaining 20 patients satisfied possible criteria only, and 11 of these patients changed categories over time to probable or definite BVFTD and showed progression on cognitive and functional measures (termed changed status). Of these 11 patients, 8 (73%) carried the C9orf72 expansion. A positive family history, memory impairment, and clinical abnormalities at presentation were key features of progression (P < .05). A continuum of neuropsychological scores, progression rates, and atrophy severity emerged across patients in probable, possible, changed status, and nonchanged status groups; patients with probable BVFTD exhibited the most severe abnormalities.

Conclusions and Relevance  Behavioral variant FTD shows variable progression over time. Clinicians can use a detailed neurologic and cognitive assessment to identify key predictive features of progression when faced with possible BVFTD, whereas a diagnosis of probable BVFTD is accurate in a clinical setting

JAMA Neurology 2015

Alteration in 5-hydroxymethylcytosine-mediated epigenetic regulation leads to Purkinje cell vulnerability in ATM deficiency

A long-standing mystery surrounding ataxia-telangiectasia is why it is mainly cerebellar neurons, Purkinje cells in particular, that appear vulnerable to ATM deficiency. Here we present data showing that 5-hydroxymethylcytosine (5hmC), a newly recognized epigenetic marker found at high levels in neurons, is substantially reduced in human ataxia-telangiectasia and Atm−/− mouse cerebellar Purkinje cells. We further show that TET1, an enzyme that converts 5-methylcytosine (5mC) to 5hmC, responds to DNA damage and manipulation of TET1 activity directly affects the DNA damage signalling and ATM-deficient neuronal cell cycle re-entry and death. Quantitative genome-wide analysis of 5hmC-containing sequences shows that in ATM deficiency there is a cerebellum- and Purkinje cell-specific shift in 5hmC enrichment in both regulatory elements and repeated sequences. Finally, we verify that TET1-mediated 5hmC production is linked to the degenerative process of Purkinje cells and behavioural deficits in Atm−/− mice. Taken together, the selective loss of 5hmC plays a critical role in driving Purkinje cell vulnerability in ATM deficiency.

Brain 2015

LRPPRC mutations cause early-onset multisystem mitochondrial disease outside of the French-Canadian population

Mitochondrial Complex IV [cytochrome c oxidase (COX)] deficiency is one of the most common respiratory chain defects in humans. The clinical phenotypes associated with COX deficiency include liver disease, cardiomyopathy and Leigh syndrome, a neurodegenerative disorder characterized by bilateral high signal lesions in the brainstem and basal ganglia. COX deficiency can result from mutations affecting many different mitochondrial proteins. The French-Canadian variant of COX-deficient Leigh syndrome is unique to the Saguenay-Lac-Saint-Jean region of Québec and is caused by a founder mutation in the LRPPRC gene. This encodes the leucine-rich pentatricopeptide repeat domain protein (LRPPRC), which is involved in post-transcriptional regulation of mitochondrial gene expression. Here, we present the clinical and molecular characterization of novel, recessive LRPPRC gene mutations, identified using whole exome and candidate gene sequencing. The 10 patients come from seven unrelated families of UK-Caucasian, UK-Pakistani, UK-Indian, Turkish and Iraqi origin. They resemble the French-Canadian Leigh syndrome patients in having intermittent severe lactic acidosis and early-onset neurodevelopmental problems with episodes of deterioration. In addition, many of our patients have had neonatal cardiomyopathy or congenital malformations, most commonly affecting the heart and the brain. All patients who were tested had isolated COX deficiency in skeletal muscle. Functional characterization of patients’ fibroblasts and skeletal muscle homogenates showed decreased levels of mutant LRPPRC protein and impaired Complex IV enzyme activity, associated with abnormal COX assembly and reduced steady-state levels of numerous oxidative phosphorylation subunits. We also identified a Complex I assembly defect in skeletal muscle, indicating different roles for LRPPRC in post-transcriptional regulation of mitochondrial mRNAs between tissues. Patient fibroblasts showed decreased steady-state levels of mitochondrial mRNAs, although the length of poly(A) tails of mitochondrial transcripts were unaffected. Our study identifies LRPPRC as an important disease-causing genne in an early-onset, multisystem and neurological mitochondrial disease, which should be considered as a cause of COX deficiency even in patients originating outside of the French-Canadian population.

Brain 2015

Characterisation of mutations of the phosphoinositide-3-kinase regulatory subunit, PIK3R2, in perisylvian polymicrogyria: a next-generation sequencing study

Background

Bilateral perisylvian polymicrogyria (BPP), the most common form of regional polymicrogyria, causes the congenital bilateral perisylvian syndrome, featuring oromotor dysfunction, cognitive impairment, and epilepsy. The causes of BPP are heterogeneous, but only a few genetic causes have been reported. The aim of this study was to identify additional genetic causes of BPP and characterise their frequency in this population.

Methods

Children (aged ≤18 years) with polymicrogyria were enrolled into our research programme from July, 1980, to October, 2015, at two centres (Florence, Italy, and Seattle, WA, USA). We obtained samples (blood and saliva) throughout this period at both centres and did whole-exome sequencing on DNA from eight trios (two parents and one affected child) with BPP in 2014. After the identification of mosaic PIK3R2 mutations in two of these eight children, we performed targeted screening of PIK3R2by two methods in a cohort of 118 children with BPP. First, we performed targeted sequencing of the entire PIK3R2 gene by single molecule molecular inversion probes (smMIPs) on 38 patients with BPP with normal to large head size. Second, we did amplicon sequencing of the recurrent PIK3R2mutation (Gly373Arg) in 80 children with various types of polymicrogyria including BPP. One additional patient had clinical whole-exome sequencing done independently, and was included in this study because of the phenotypic similarity to our cohort.

Findings

We identified a mosaic mutation (Gly373Arg) in a regulatory subunit of the PI3K-AKT-mTOR pathway,PIK3R2, in two children with BPP. Of the 38 patients with BPP and normal to large head size who underwent targeted next-generation sequencing by smMIPs, we identified constitutional and mosaicPIK3R2 mutations in 17 additional children. In parallel, one patient had the recurrent PIK3R2mutation identified by clinical whole-exome sequencing. Seven of these 20 patients had BPP alone, and 13 had BPP in association with features of the megalencephaly-polymicrogyria-polydactyly-hydrocephalus (MPPH) syndrome. 19 patients had the same mutation (Gly373Arg), and one had a nearby missense mutation (Lys376Glu). Mutations were constitutional in 12 patients and mosaic in eight patients. In patients with mosaic mutations, we noted substantial variation in alternate (mutant) allele levels, ranging from ten (3%) of 377 reads to 39 (37%) of 106 reads, equivalent to 5–73% of cells analysed. Levels of mosaicism varied from undetectable to 37 (17%) of 216 reads in blood-derived DNA compared with 2030 (29%) of 6889 reads to 275 (43%) of 634 reads in saliva-derived DNA.

Interpretation

Constitutional and mosaic mutations in the PIK3R2 gene are associated with developmental brain disorders ranging from BPP with a normal head size to the MPPH syndrome. The phenotypic variability and low-level mosaicism, which challenge conventional molecular methods, have important implications for genetic testing and counselling

Lancet Neurology 2015

ADSSL1 mutation relevant to autosomal recessive adolescent-onset distal myopathy.

OBJECTIVE:

Distal myopathy is a heterogeneous group of muscle diseases characterized by predominant distal muscle weakness. A study was done to identify the underlying cause of autosomal recessive adolescent-onset distal myopathy.

METHODS:

Four patients from two unrelated Korean families were evaluated. To isolate the genetic cause, exome sequencing was performed. In vitro and in vivo assays using myoblast cells and zebrafish models were performed to examine the ADSSL1 mutation causing myopathy pathogenesis.

RESULTS:

Patients had an adolescent-onset distal myopathy phenotype which included distal dominant weakness, facial muscle weakness, rimmed vacuole, and mild elevation of serum creatine kinase. Exome sequencing identified completely cosegregating compound heterozygous mutations (p.D304N and p.I350fs) in ADSSL1 which encodes a muscle-specific adenylosuccinate synthase in both families. None of the controls had both mutations, and the mutation sites were located in well conserved regions. Both the D304N and I350fs mutations in ADSSL1 led to decreased enzymatic activity. The knock-down of the adssl1 gene significantly inhibited the proliferation of mouse myoblast cells, and the addition of human wild-type ADSSL1 reversed the reduced viability. In an adssl1 knock-downed zebrafish model, muscle fibers were severely disrupted, which was evaluated by myosin expression and birefringence. In these conditions, supplementing wild-type ADSSL1 protein reversed the muscle defect.

INTERPRETATION:

We suggest that mutations in ADSSL1 are the novel genetic cause of the autosomal recessive adolescent-onset distal myopathy. This study broadens the genetic and clinical spectrum of distal myopathy and will be useful for exact molecular diagnostics. This article is protected by copyright. All rights reserved

Annals of Neurology 2015

Increased CSF biomarkers of angiogenesis in Parkinson disease

Objective: To study biomarkers of angiogenesis in Parkinson disease (PD), and how these are associated with clinical characteristics, blood–brain barrier (BBB) permeability, and cerebrovascular disease.

Methods: In this cross-sectional analysis, 38 elderly controls and 100 patients with PD (82 without dementia and 18 with dementia) were included from the prospective Swedish BioFinder study. CSF samples were analyzed for the angiogenesis biomarkers vascular endothelial growth factor (VEGF); its receptors, VEGFR-1 and VEGFR-2; placental growth factor (PlGF); angiopoietin 2 (Ang2); and interleukin-8. BBB permeability, white matter lesions (WMLs), and cerebral microbleeds (CMB) were assessed. CSF angiogenesis biomarkers were also measured in 2 validation cohorts: (1) 64 controls and 87 patients with PD with dementia; and (2) 35 controls and 93 patients with neuropathologically confirmed diagnosis of PD with and without dementia.

Results: Patients with PD without dementia displayed higher CSF levels of VEGF, PlGF, and sVEGFR-2, and lower levels of Ang2, compared to controls. Similar alterations in VEGF, PlGF, and Ang2 levels were observed in patients with PD with dementia. Angiogenesis markers were associated with gait difficulties and orthostatic hypotension as well as with more pronounced BBB permeability, WMLs, and CMB. Moreover, higher levels of VEGF and PlGF levels were associated with increased CSF levels of neurofilament light (a marker of neurodegeneration) and monocyte chemotactic protein–1 (a marker of glial activation). The main results were validated in the 2 additional cohorts.

Conclusions: CSF biomarkers of angiogenesis are increased in PD, and they are associated with gait difficulties, BBB dysfunction, WMLs, and CMB. Abnormal angiogenesis may be important in PD pathogenesis and contribute to dopa-resistant symptoms.

Neurology 2015

Risk of rupture of unruptured cerebral aneurysms in elderly patients

Objectives: The aim of this study was to identify risk factors for rupture of unruptured cerebral aneurysms (UCAs) in elderly Japanese patients aged 70 years or older.

Methods: The participants included all patients 70 years of age or older in 3 prospective studies in Japan (the Unruptured Cerebral Aneurysm Study of Japan [UCAS Japan], UCAS II, and the prospective study at the Jikei University School of Medicine). A total of 1,896 patients aged 70 years or older with 2,227 UCAs were investigated. The median and mean follow-up periods were 990 and 802.7 days, respectively.

Results: The mean aneurysm size was 6.2 ± 3.9 mm. Sixty-eight patients (3.6%) experienced subarachnoid hemorrhage during the follow-up period. Multivariable analysis per patient revealed that in patients aged 80 years or older (hazard ratio [HR], 2.02; 95% confidence interval [CI], 1.16–3.49, p = 0.012), aneurysms 7 mm or larger (HR, 3.08; 95% CI, 1.35–7.03, p = 0.007 for 7–9 mm; HR, 7.82; 95% CI, 3.60–16.98, p < 0.001 for 10–24 mm; and HR, 43.31; 95% CI, 12.55–149.42, p < 0.001 for ≥25 mm) and internal carotid–posterior communicating artery aneurysms (HR, 2.45; 95% CI, 1.23–4.88, p = 0.011) were independent predictors for UCA rupture in elderly patients.

Conclusions: In our pooled analysis of prospective cohorts in Japan, patient age and aneurysm size and location were significant risk factors for UCA rupture in elderly patients.

Neurology 2015

Stroke risk stratification in acute dizziness presentations A prospective imaging-based study

Objective: To estimate the ability of bedside information to risk stratify stroke in acute dizziness presentations.

Methods: Surveillance methods were used to identify patients with acute dizziness and nystagmus or imbalance, excluding those with benign paroxysmal positional vertigo, medical causes, or moderate to severe neurologic deficits. Stroke was defined as acute infarction or intracerebral hemorrhage on a clinical or research MRI performed within 14 days of dizziness onset. Bedside information comprised history of stroke, the ABCD² score (age, blood pressure, clinical features, duration, and diabetes), an ocular motor (OM)-based assessment (head impulse test, nystagmus pattern [central vs other], test of skew), and a general neurologic examination for other CNS features. Multivariable logistic regression was used to determine the association of the bedside information with stroke. Model calibration was assessed using low (<5%), intermediate (5% to <10%), and high (≥10%) predicted probability risk categories.

Results: Acute stroke was identified in 29 of 272 patients (10.7%). Associations with stroke were as follows: ABCD²score (continuous) (odds ratio [OR] 1.74; 95% confidence interval [CI] 1.20–2.51), any other CNS features (OR 2.54; 95% CI 1.06–6.08), OM assessment (OR 2.82; 95% CI 0.96–8.30), and prior stroke (OR 0.48; 95% CI 0.05–4.57). No stroke cases were in the model's low-risk probability category (0/86, 0%), whereas 9 were in the moderate-risk category (9/94, 9.6%) and 20 were in the high-risk category (20/92, 21.7%).

Conclusion: In acute dizziness presentations, the combination of ABCD² score, general neurologic examination, and a specialized OM examination has the capacity to risk-stratify acute stroke on MRI

Neurology 2015

Mutations in the MORC2 gene cause axonal Charcot–Marie–Tooth disease

http://brain.oxfordjournals.org/content/early/2015/10/24/brain.awv311

Brain 2015

Attitudes of Research Participants and the General Public Regarding Disclosure of Alzheimer Disease Research Results

Importance  Results of Alzheimer disease (AD) research assessments typically are not disclosed to participants. Recent research has suggested interest in disclosure, but, to our knowledge, few studies have accounted for awareness of potential benefits and limitations of disclosure.

Objective  To determine the attitudes of cognitively normal research participants and members of the general public regarding disclosure of AD research results.

Design, Setting, and Participants  Participants in a longitudinal aging study (Alzheimer Disease Research Center [ADRC]) were given preintervention and postintervention surveys about disclosure attitudes. In a general public sample (The American Panel Survey), participants responded to a similar survey about disclosure attitudes.

Interventions  Participants in the ADRC sample were randomly assigned to a group (n = 119) that read an education intervention about the usefulness of AD biomarkers or to a placebo group (n = 100) that read as its intervention general information about the ADRC. Participants in the general public sample read a brief vignette describing participation in a longitudinal AD study.

Main Outcome and Measure  Interest in disclosure of AD research results.

Results  Cognitively normal ADRC participants (n = 219) were 60.7% (n = 133) female, 83.6% (n = 183) of white race, and reported a mean of 15.91 years of education. Twenty-nine individuals refused participation. The American Panel Survey participants (n = 1418) indicated they did not have AD and were 50.5% (n = 716) female, 76.7% (n = 1087) of white race, and reported a mean of 13.85 years of education. Overall, 77.6% of eligible participants (1583 of 2041) completed the survey in July 2014. Interest in disclosure was high among the ADRC participants (55.1% [119 of 216] were “extremely interested”). Viewing the education intervention predicted lower interest in disclosure (odds ratio, 2.01; 95% CI, 1.15-3.53; P = .02). High subjective risk of AD, a family history of AD, and minimal attendance at research meetings were associated with high interest after the intervention. In the general public, interest was lower overall (12.5% [174 of 1389] were “extremely interested”), but the subset of participants most likely to join an AD research study reported higher interest (43.5% [40 of 92] were extremely interested).

Conclusions and Relevance  Experience with AD appears to increase interest in disclosure of AD research results. Learning about potential limitations of disclosure somewhat tempered interest. These findings should inform the development of disclosure policies for asymptomatic individuals in AD studies

JAMA Neurology

A Thalamocortical Mechanism for the Absence of Overt Motor Behavior in Covertly Aware Patients

Importance  It is well accepted that a significant number of patients in a vegetative state are covertly aware and capable of following commands by modulating their neural responses in motor imagery tasks despite remaining nonresponsive behaviorally. To date, there have been few attempts to explain this dissociation between preserved covert motor behavior and absent overt motor behavior.

Objectives  To investigate the differential neural substrates of overt and covert motor behavior and assess the structural integrity of the underlying networks in behaviorally nonresponsive patients.

Design, Setting, and Participants  A case-control study was conducted at an academic center between February 7, 2012, and November 6, 2014. Data analysis was performed between March 2014 and June 2015. Participants included a convenience sample of 2 patients with severe brain injury: a paradigmatic patient who fulfilled all clinical criteria for the vegetative state but produced repeated evidence of covert awareness (patient 1) and, as a control case, a patient with similar clinical variables but capable of behavioral command following (patient 2). Fifteen volunteers participated in the study as a healthy control group.

Main Outcomes and Measures  We used dynamic causal modeling of functional magnetic resonance imaging to compare voluntary motor imagery and motor execution. We then used fiber tractography to assess the structural integrity of the fibers that our functional magnetic resonance imaging study revealed as essential for successful motor execution.

Results  The functional magnetic resonance imaging study revealed that, in contrast to mental imagery, motor execution was associated with an excitatory coupling between the thalamus and primary motor cortex (Bayesian model selection; winning model Bayes factors >17). Moreover, we detected a selective structural disruption in the fibers connecting these 2 regions in patient 1 (fractional anisotropy, 0.294; P = .047) but not in patient 2 (fractional anisotropy, 0.413; P = .35).

Conclusions and Relevance  These results suggest a possible biomarker for the absence of intentional movement in covertly aware patients (ie, specific damage to motor thalamocortical fibers), highlight the importance of the thalamus for the execution of intentional movements, and may provide a target for restorative therapies in behaviorally nonresponsive patients.

JAMA Neurology 2015

Prolonged-release oxycodone–naloxone for treatment of severe pain in patients with Parkinson's disease (PANDA): a double-blind, randomised, placebo-controlled trial

Summary

Background

Pain is a common non-motor symptom of Parkinson's disease. We investigated the analgesic efficacy of prolonged-release oxycodone–naloxone (OXN PR) in patients with Parkinson's disease and chronic, severe pain.

Methods

We did this phase 2 study in 47 secondary care centres in the Czech Republic, Germany, Hungary, Poland, Romania, Spain, and the UK. We enrolled patients with Hoehn and Yahr Stage II–IV Parkinson's disease, at least one type of severe pain, and an average 24-h pain score of at least 6 (assessed on an 11-point rating scale from 0=no pain to 10=pain as bad as you can imagine). Participants were randomly assigned (1:1) with a validated automated system (block size four) to either oral OXN PR or placebo for 16 weeks (starting dose oxycodone 5 mg, naloxone 2·5 mg, twice daily). Patients and investigators were masked to treatment assignment. The primary endpoint was average 24-h pain score at 16 weeks in the full analysis population. This study is registered with EudraCT (2011-002901-31) and ClinicalTrials.gov (NCT01439100).

Findings

We enrolled 202 patients; 93 were assigned to OXN PR and 109 to placebo; the full analysis population consisted of 88 patients versus 106 patients. Least squares mean average 24-h pain score at 16 weeks in the full analysis population was 5·0 (95% CI 4·5 to 5·5) in the OXN PR group versus 5·6 (5·1 to 6·0) in the placebo group (difference −0·6, 95% CI −1·3 to 0·0; p=0·058). Similar proportions of patients in each group had adverse events (60/92 [65%] vs 76/109 [70%]), treatment-related adverse events (52/92 [57%] vs 62/109 [57%]), and serious adverse events (5/92 [5%] vs 7/109 [6%]). Treatment-related nausea was more common in the OXN PR group than in the placebo group (16/92 [17%] vs 10/109 [9%]), as was treatment-related constipation (16/92 [17%] vs 6/109 [6%]).

Interpretation

The primary endpoint, based on the full analysis population at week 16, was not significant. Nonetheless, the results of this study highlight the potential efficacy of OXN PR for patients with Parkinson's disease-related pain and might warrant further research on OXN PR in this setting.

Lancet Neurology 2015

No association of multiple sclerosis activity and progression with EBV or tobacco use in BENEFIT

Objective: To evaluate whether Epstein-Barr virus (EBV) immunoglobulin G (IgG) antibody levels or tobacco use were associated with conversion to multiple sclerosis (MS) or MS progression/activity in patients presenting with clinically isolated syndrome (CIS).

Methods: In this prospective, longitudinal study, we measured EBV IgG antibody and cotinine (biomarker of tobacco use) levels at up to 4 time points (baseline, months 6, 12, and 24) among 468 participants with CIS enrolled in the BENEFIT (Betaferon/Betaseron in Newly Emerging Multiple Sclerosis for Initial Treatment) clinical trial. Outcomes included time to conversion to clinically definite or McDonald MS, number of relapses, Expanded Disability Status Scale (EDSS) changes, brain and T2 lesion volume changes, and number of new active lesions over 5 years. Analyses were adjusted for age, sex, treatment allocation, baseline serum 25-hydroxyvitamin D level, number of T2 lesions, body mass index, EDSS, steroid treatment, and CIS onset type.

Results: We found no associations between any EBV IgG antibody or cotinine levels with conversion from CIS to MS or MS progression as measured by EDSS or activity clinically or on MRI. The relative risk of conversion from CIS to clinically definite MS was 1.14 (95% confidence interval 0.76–1.72) for the highest vs the lowest quintile of EBNA-1 IgG levels, and 0.96 (95% confidence interval 0.71–1.31) for cotinine levels >25 ng/mL vs <10.

Conclusions: Neither increased levels of EBV IgG antibodies, including against EBNA-1, nor elevated cotinine levels indicative of tobacco use, were associated with an increased risk of CIS conversion to MS, or MS activity or progression over a 5-year follow-up.

Neurology 2015

Use of amyloid-PET to determine cutpoints for CSF markers A multicenter study

Objectives: To define CSF β-amyloid 1–42 (Aβ₄₂) cutpoints to detect cortical amyloid deposition as assessed by¹¹C-Pittsburgh compound B ([¹¹C]PiB)-PET and to compare these calculated cutpoints with cutpoints currently used in clinical practice.

Methods: We included 433 participants (57 controls, 99 with mild cognitive impairment, 195 with Alzheimer disease [AD] dementia, and 82 with non-AD dementia) from 5 European centers. We calculated for each center and for the pooled cohort CSF Aβ₄₂ and Aβ₄₂/tau ratio cutpoints for cortical amyloid deposition based on visual interpretation of [¹¹C]PiB-PET images.

Results: Amyloid-PET–based calculated CSF Aβ₄₂ cutpoints ranged from 521 to 616 pg/mL, whereas existing clinical-based cutpoints ranged from 400 to 550 pg/mL. Using the calculated cutpoint from the pooled sample (557 pg/mL), concordance between CSF Aβ₄₂ and amyloid-PET was 84%. Similar concordance was found when using a dichotomized Aβ₄₂/tau ratio. Exploratory analysis showed that participants with a positive amyloid-PET and normal CSF Aβ₄₂ levels had higher CSF tau and phosphorylated tau levels and more often had mild cognitive impairment or AD dementia compared with participants who had negative amyloid-PET and abnormal CSF Aβ₄₂ levels.

Conclusions: Amyloid-PET–based CSF Aβ₄₂ cutpoints were higher and tended to reduce intercenter variability compared with clinical-based cutpoints. Discordant participants with normal CSF Aβ₄₂ and a positive amyloid-PET may be more likely to have AD-related amyloid pathology than participants with abnormal CSF Aβ₄₂ and a negative amyloid-PET.

Classification of evidence: This study provides Class II evidence that an amyloid-PET–based CSF Aβ₄₂ cutpoint identifies individuals with amyloid deposition with a sensitivity of 87% and specificity of 80%.

Neurology 2015

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