Showing papers in "Annals of Neurology in 2012"

Evidence-based path to newborn screening for Duchenne muscular dystrophy.

Abstract: Objective: Creatine kinase (CK) levels are increased on dried blood spots in newborns related to the birthing process. As a marker for newborn screening, CK in Duchenne muscular dystrophy (DMD) results in false-positive testing. In this report, we introduce a 2-tier system using the dried blood spot to first assess CK with follow-up DMD gene testing. Methods: A fluorometric assay based upon the enzymatic transphosphorylation of adenosine diphosphate to adenosine triphosphate was used to measure CK activity. Preliminary studies established a population-based range of CK in newborns using 30,547 deidentified anonymous dried blood spot samples. Mutation analysis used genomic DNA extracted from the dried blood spot followed by whole genome amplification with assessment of single-/multiexon deletions/duplications in the DMD gene using multiplex ligation-dependent probe amplification. Results: DMD gene mutations (all exonic deletions) were found in 6 of 37,649 newborn male subjects, all of whom had CK levels >2,000U/l. In 3 newborns with CK >2,000U/l in whom DMD gene abnormalities were not found, we identified limb-girdle muscular dystrophy gene mutations affecting DYSF, SGCB, and FKRP. Interpretation: A 2-tier system of analysis for newborn screening for DMD has been established. This path for newborn screening fits our health care system, minimizes false-positive testing, and uses predetermined levels of CK on dried blood spots to predict DMD gene mutations. ANN NEUROL 2012;71:304–313

Meta-analysis of early nonmotor features and risk factors for Parkinson disease.

Abstract: Objective: To evaluate the association between diagnosis of Parkinson disease (PD) and risk factors or early symptoms amenable to population-based screening. Methods: A systematic review and meta-analysis of risk factors for PD. Results: The strongest associations with later diagnosis of PD were found for having a first-degree or any relative with PD (odds ratio [OR], 3.23; 95% confidence interval [CI], 2.65–3.93 and OR, 4.45; 95% CI, 3.39–5.83) or any relative with tremor (OR, 2.74; 95% CI, 2.10–3.57), constipation (relative risk [RR], 2.34; 95% CI, 1.55–3.53), or lack of smoking history (current vs never: RR, 0.44; 95% CI, 0.39–0.50), each at least doubling the risk of PD. Further positive significant associations were found for history of anxiety or depression, pesticide exposure, head injury, rural living, beta-blockers, farming occupation, and well-water drinking, and negative significant associations were found for coffee drinking, hypertension, nonsteroidal anti-inflammatory drugs, calcium channel blockers, and alcohol, but not for diabetes mellitus, cancer, oral contraceptive pill use, surgical menopause, hormone replacement therapy, statins, acetaminophen/paracetamol, aspirin, tea drinking, history of general anesthesia, or gastric ulcers. In the systematic review, additional associations included negative associations with raised serum urate, and single studies or studies with conflicting results. Interpretation: The strongest risk factors associated with later PD diagnosis are having a family history of PD or tremor, a history of constipation, and lack of smoking history. Further factors also but less strongly contribute to risk of PD diagnosis or, as some premotor symptoms, require further standardized studies to demonstrate the magnitude of risk associated with them. ANN NEUROL 2012;72:893–901

An operational approach to National Institute on Aging–Alzheimer's Association criteria for preclinical Alzheimer disease

Abstract: Objective: A workgroup commissioned by the Alzheimer's Association (AA) and the National Institute on Aging (NIA) recently published research criteria for preclinical Alzheimer disease (AD). We performed a preliminary assessment of these guidelines. Methods: We employed Pittsburgh compound B positron emission tomography (PET) imaging as our biomarker of cerebral amyloidosis, and 18fluorodeoxyglucose PET imaging and hippocampal volume as biomarkers of neurodegeneration. A group of 42 clinically diagnosed AD subjects was used to create imaging biomarker cutpoints. A group of 450 cognitively normal (CN) subjects from a population-based sample was used to develop cognitive cutpoints and to assess population frequencies of the different preclinical AD stages using different cutpoint criteria. Results: The new criteria subdivide the preclinical phase of AD into stages 1 to 3. To classify our CN subjects, 2 additional categories were needed. Stage 0 denotes subjects with normal AD biomarkers and no evidence of subtle cognitive impairment. Suspected non-AD pathophysiology (SNAP) denotes subjects with normal amyloid PET imaging, but abnormal neurodegeneration biomarker studies. At fixed cutpoints corresponding to 90% sensitivity for diagnosing AD and the 10th percentile of CN cognitive scores, 43% of our sample was classified as stage 0, 16% stage 1, 12 % stage 2, 3% stage 3, and 23% SNAP. Interpretation: This cross-sectional evaluation of the NIA-AA criteria for preclinical AD indicates that the 1–3 staging criteria coupled with stage 0 and SNAP categories classify 97% of CN subjects from a population-based sample, leaving only 3% unclassified. Future longitudinal validation of the criteria will be important ANN NEUROL 2012;

Procedural pain and brain development in premature newborns

Abstract: Objective Preterm infants are exposed to multiple painful procedures in the neonatal intensive care unit (NICU) during a period of rapid brain development. Our aim was to examine relationships between procedural pain in the NICU and early brain development in very preterm infants.

Amyloid deposition, hypometabolism, and longitudinal cognitive decline.

Abstract: The emergence of positron emission tomography (PET) for imaging fibrillar β-amyloid (Aβ) in vivo is a critical development in the study of Alzheimer disease (AD). Recent amyloid PET studies have raised important questions about how amyloid deposition influences cognitive trajectories, particularly early in the course of disease. Determining the consequences of Aβ at different phases of disease and the relationship between Aβ and other well-known biomarkers of AD such as 18F-fluorodeoxyglucose (FDG) remain important questions that will contribute to our understanding of the clinical relevance of amyloid PET imaging and the development of effective therapies for AD. Hypometabolism, measured with FDG-PET, is associated with cognitive decline1 and conversion from mild cognitive impairment (MCI) to AD.2,3 Recent work has demonstrated that the presence of amyloid is also associated with decline4,5 and conversion.6,7 Integrating data from a variety of sources, researchers have proposed that the time course of Aβ deposition and hypometabolism depends on disease stage,8–10 such that amyloid deposition precedes synaptic and neuronal dysfunction, which is in turn followed by cognitive decline. This model has been supported by several studies comparing the 2 PET measurements with respect to longitudinal decline,11,12 but this work has been limited by small sample sizes and access to patients at different phases of disease. In this study, FDG-PET and amyloid PET data acquired through the Alzheimer’s Disease Neuroimaging Initiative (ADNI) made it possible to compare these measurements in a large sample at different levels of disease severity. [18F]Florbetapir is a PET ligand that has been recently added to the ADNI imaging protocol, and has been validated in a study demonstrating close correspondence between cortical amyloid deposition measured with florbetapir in end-of-life patients and immunohistochemistry measurements of fibrillar Aβ at autopsy.13 We examined cross-sectional relationships between Aβ (measured with florbetapir), hypometabolism (measured with FDG-PET), and cognitive performance (measured with the cognitive subscale of the Alzheimer’s Disease Assessment Scale [ADAS-cog]) in the ADNI population. A subset of the normal and MCI participants had retrospective longitudinal cognitive performance data available. Examining PET measurements (florbetapir, FDG) and cognitive change over time in these 2 diagnostic groups (normal, MCI) allowed us to test the hypothesis that amyloid deposition precedes hypometabolism and both are linked to longitudinal decline.

The blood–brain barrier in health and disease

Abstract: The blood-brain barrier (BBB) is a term used to describe a series of properties possessed by the vasculature of the central nervous system (CNS) that tightly regulate the movement of ions, molecules, and cells between the blood and the CNS. This barrier is crucial to provide the appropriate environment to allow for proper neural function, as well as protect the CNS from injury and disease. In this review, I discuss the cellular and molecular composition of the BBB and how the development and function of the BBB is regulated by interactions with the CNS microenvironment. I further discuss what is known about BBB dysfunction during CNS injury and disease, as well as methodology used to deliver drugs across the BBB to the CNS.

Glucocerebrosidase deficiency in substantia nigra of parkinson disease brains

Abstract: The lysosomal storage disorder Gaucher disease (GD) is caused by autosomal recessive mutations in the glucocerebrosidase (GBA) gene. GBA encodes a lysosomal enzyme (GCase) that catalyses the metabolism of the sphingolipid glucosylceramide to ceramide and glucose. Deficiency of GCase activity results in accumulation of substrate in the lysosomes of several tissues, including brain. Mutations in GBA result in 3 clinical manifestations. Type 1 GD occurs in both children and adults and predominantly impacts on the non-neuronal organs, whereas types 2 and 3 have an onset in childhood and adolescence, respectively, and exhibit neurological deficits.1 Parkinson disease (PD) is primarily characterized by the motor symptoms of resting tremor, bradykinesia, rigidity, and postural instability. Pathological hallmarks include loss of dopaminergic neurons from the substantia nigra (SN) and the presence of cytoplasmic inclusions known as Lewy bodies in the surviving cells of affected brain regions.2 Typical parkinsonism is among the neurological complications of GD (including type 1).3, 4 The neuropathology of GD brains includes the typical hallmarks of PD, such as cortical and brainstem Lewy bodies.5 Heterozygote carriers of GBA mutations also have an increased frequency of PD, and these mutations are the most common genetic risk factor for developing the disease.6–8 Although the pathogenesis of PD is still unknown, the accumulation of α-synuclein and other ubiquitinated proteins in Lewy bodies has implicated protein mishandling as a putative cause. The proteasome and lysosomes are the 2 principal mechanisms for degrading cellular constituents. Autophagy utilizes lysosomes to degrade long-lived proteins, misfolded/aggregated proteins, and organelles such as mitochondria.9 Defective autophagy and/or lysosomal depletion have been implicated in PD.10–13 Cellular or animal models of GCase deficiency have caused α-synuclein accumulation.14–18 GCase has also been suggested to bind directly with α-synuclein in lysosomes19 and the GCase substrate glucosylceramide stabilizes soluble oligomeric α-synuclein species.18 These observations have led to the notion that GCase deficiency might contribute to the α-synuclein aggregation characteristic of PD pathology. Despite the recognized association between GBA mutations and PD, it is unknown how heterozygous GBA mutations affect GCase activity in PD brains. In this paper, we provide the first report of the activity of GCase in several regions of PD brains from GBA mutation carriers and sporadic PD brains. GCase deficiency was greatest in the SN of PD brains with GBA mutations. This loss of activity was in part mediated by a decrease in GCase protein levels. GCase activity was also significantly decreased in the SN of sporadic PD brains.

Inflammation during fetal and neonatal life: Implications for neurologic and neuropsychiatric disease in children and adults

Abstract: Inflammation is increasingly recognized as being of both physiological and pathological importance in the immature brain. The rationale of this review is to present an update on this topic with focus on long-term consequences of inflammation during childhood and in adults. The immature brain can be exposed to inflammation in connection with viral or bacterial infection during pregnancy or as a result of sterile central nervous system (CNS) insults. Through efficient anti-inflammatory and reparative processes, inflammation may resolve without any harmful effects on the brain. Alternatively, inflammation contributes to injury or enhances CNS vulnerability. Acute inflammation can also be shifted to a chronic inflammatory state and/or adversely affect brain development. Hypothetically, microglia are the main immunocompetent cells in the immature CNS, and depending on the stimulus, molecular context, and timing, these cells will acquire various phenotypes, which will be critical regarding the CNS consequences of inflammation. Inflammation has long-term consequences and could speculatively modify the risk of a variety of neurological disorders, including cerebral palsy, autism spectrum disorders, schizophrenia, multiple sclerosis, cognitive impairment, and Parkinson disease. So far, the picture is incomplete, and data mostly experimental. Further studies are required to strengthen the associations in humans and to determine whether novel therapeutic interventions during the perinatal period can influence the occurrence of neurological disease later in life.

Gain of function NaV1.7 mutations in idiopathic small fiber neuropathy

Abstract: OBJECTIVE: Small nerve fiber neuropathy (SFN) often occurs without apparent cause, but no systematic genetic studies have been performed in patients with idiopathic SFN (I-SFN). We sought to identify a genetic basis for I-SFN by screening patients with biopsy-confirmed idiopathic SFN for mutations in the SCN9A gene, encoding voltage-gated sodium channel Na(V)1.7, which is preferentially expressed in small diameter peripheral axons. METHODS: Patients referred with possible I-SFN, who met the criteria of >/=2 SFN-related symptoms, normal strength, tendon reflexes, vibration sense, and nerve conduction studies, and reduced intraepidermal nerve fiber density (IENFD) plus abnormal quantitative sensory testing (QST) and no underlying etiology for SFN, were assessed clinically and by screening of SCN9A for mutations and functional analyses. RESULTS: Twenty-eight patients who met stringent criteria for I-SFN including abnormal IENFD and QST underwent SCN9A gene analyses. Of these 28 patients with biopsy-confirmed I-SFN, 8 were found to carry novel mutations in SCN9A. Functional analysis revealed multiple gain of function changes in the mutant channels; each of the mutations rendered dorsal root ganglion neurons hyperexcitable. INTERPRETATION: We show for the first time that gain of function mutations in sodium channel Na(V)1.7, which render dorsal root ganglion neurons hyperexcitable, are present in a substantial proportion (28.6%; 8 of 28) of patients meeting strict criteria for I-SFN. These results point to a broader role of Na(V)1.7 mutations in neurological disease than previously considered from studies on rare genetic syndromes, and suggest an etiological basis for I-SFN, whereby expression of gain of function mutant sodium channels in small diameter peripheral axons may cause these fibers to degenerate.

High-frequency oscillations as a new biomarker in epilepsy.

Abstract: The discovery that electroencephalography (EEG) contains useful information at frequencies above the traditional 80Hz limit has had a profound impact on our understanding of brain function. In epilepsy, high-frequency oscillations (HFOs, >80Hz) have proven particularly important and useful. This literature review describes the morphology, clinical meaning, and pathophysiology of epileptic HFOs. To record HFOs, the intracranial EEG needs to be sampled at least at 2,000Hz. The oscillatory events can be visualized by applying a high-pass filter and increasing the time and amplitude scales, or EEG time-frequency maps can show the amount of high-frequency activity. HFOs appear excellent markers for the epileptogenic zone. In patients with focal epilepsy who can benefit from surgery, invasive EEG is often required to identify the epileptic cortex, but current information is sometimes inadequate. Removal of brain tissue generating HFOs has been related to better postsurgical outcome than removing the seizure onset zone, indicating that HFOs may mark cortex that needs to be removed to achieve seizure control. The pathophysiology of epileptic HFOs is challenging, probably involving populations of neurons firing asynchronously. They differ from physiological HFOs in not being paced by rhythmic inhibitory activity and in their possible origin from population spikes. Their link to the epileptogenic zone argues that their study will teach us much about the pathophysiology of epileptogenesis and ictogenesis. HFOs show promise for improving surgical outcome and accelerating intracranial EEG investigations. Their potential needs to be assessed by future research.

Neuropathologic substrates of Parkinson disease dementia.

Abstract: Objective To examine the neuropathological substrates of cognitive dysfunction and dementia in Parkinson’s disease (PD).

KCNQ2 encephalopathy: emerging phenotype of a neonatal epileptic encephalopathy.

Abstract: OBJECTIVE: KCNQ2 and KCNQ3 mutations are known to be responsible for benign familial neonatal seizures (BFNS). A few reports on patients with a KCNQ2 mutation with a more severe outcome exist, but a definite relationship has not been established. In this study we investigated whether KCNQ2/3 mutations are a frequent cause of epileptic encephalopathies with an early onset and whether a recognizable phenotype exists. METHODS: We analyzed 80 patients with unexplained neonatal or early-infantile seizures and associated psychomotor retardation for KCNQ2 and KCNQ3 mutations. Clinical and imaging data were reviewed in detail. RESULTS: We found 7 different heterozygous KCNQ2 mutations in 8 patients (8/80; 10%); 6 mutations arose de novo. One parent with a milder phenotype was mosaic for the mutation. No KCNQ3 mutations were found. The 8 patients had onset of intractable seizures in the first week of life with a prominent tonic component. Seizures generally resolved by age 3 years but the children had profound, or less frequently severe, intellectual disability with motor impairment. Electroencephalography (EEG) at onset showed a burst-suppression pattern or multifocal epileptiform activity. Early magnetic resonance imaging (MRI) of the brain showed characteristic hyperintensities in the basal ganglia and thalamus that later resolved. INTERPRETATION: KCNQ2 mutations are found in a substantial proportion of patients with a neonatal epileptic encephalopathy with a potentially recognizable electroclinical and radiological phenotype. This suggests that KCNQ2 screening should be included in the diagnostic workup of refractory neonatal seizures of unknown origin.

Epilepsy, suicidality, and psychiatric disorders: a bidirectional association.

Abstract: OBJECTIVE: A study was undertaken to determine whether psychiatric disorders associated with suicide are more common in incident epilepsy than in matched controls without epilepsy, before and after epilepsy diagnosis. METHODS: A matched, longitudinal cohort study was conducted in the UK General Practice Research Database. A total of 3,773 cases diagnosed with epilepsy between the ages of 10 and 60 years were compared to 14,025 controls matched by year of birth, sex, general practice, and years of medical records before the index date. We examined first diagnosis of psychosis, depression, anxiety, and suicidality in each of the 3 years before and after the index date and annual prevalence of suicide. Referent diagnoses were eczema and acute surgery. The incidence rate ratio (IRR) was calculated for each year in the study period; the prevalence ratio (PR) was calculated for suicidality. RESULTS: The IRR of psychosis, depression, and anxiety was significantly increased for all years before epilepsy diagnosis (IRR, 1.5-15.7) and after diagnosis (IRR, 2.2-10.9) and for suicidality before epilepsy diagnosis (IRR, 3.1-4.5) and 1 year after diagnosis (IRR, 5.3). The PR was increased for suicide attempt before epilepsy onset (PR, 2.6-5.2) and after onset (PR, 2.4-5.6). Eczema and acute surgery were both associated with epilepsy in the first and third year after diagnosis. INTERPRETATION: Epilepsy is associated with an increased onset of psychiatric disorders and suicide before and after epilepsy diagnosis. These relations suggest common underlying pathophysiological mechanisms that both lower seizure threshold and increase risk for psychiatric disorders and suicide. ANN NEUROL 2012. Language: en

Morvan syndrome: Clinical and serological observations in 29 cases

Abstract: Objective: A study was undertaken to describe the clinical spectrum, voltage-gated potassium channel (VGKC) complex antibody specificities, and central nervous system localization of antibody binding in 29 patients diagnosed with Morvan syndrome (MoS). Methods: Clinical data were collected using questionnaires. Radioimmunoassay, cell-based assays, and mouse brain immunohistochemistry were used to characterize the serum antibodies. Results: Neuromyotonia (100%), neuropsychiatric features (insomnia 89.7%, confusion 65.5%, amnesia 55.6%, hallucinations 51.9%), dysautonomia (hyperhidrosis 86.2%, cardiovascular 48.3%), and neuropathic pain (62.1%) were the most common manifestations. A total of 93.1% of MoS patients were male. VGKC-complex antibodies were present in 23 of 29 (79%) MoS patients at referral; 24 of 27 available sera had CASPR2, LGI1, or both CASPR2 and LGI1 antibodies (3 also with contactin-2 antibodies). CASPR2 antibodies were generally higher titer than LGI1 antibodies. Tumors (41.4%), mainly thymomas, were associated with CASPR2 antibodies and a poor prognosis, whereas LGI1 antibodies were associated with serum hyponatremia. In brain tissue regions including the hypothalamus, raphe, and locus coeruleus, commercial antibodies to LGI1 bound to neuronal cell bodies including the antidiuretic hormone-secreting and orexin-secreting hypothalamic neurons, whereas CASPR2 commercial antibodies bound more often to the neuropil. MoS antibodies bound similarly, but there was evidence of additional antibodies in some sera that were not adsorbed by LGI1- or CASPR2-expressing cells and bound to mouse Caspr2−/− tissue. Interpretation: MoS is clinically distinct from other VGKC-complex antibody-associated conditions, and usually is associated with high-titer CASPR2 antibodies, often accompanied by lower-titer LGI1 antibodies. CASPR2 and LGI1 antibodies bind to multiple brain regions, which helps to explain the multifocal clinical features of this disease, but other antibodies are likely to play a role in some patients and need to be characterized in future studies. ANN NEUROL 2012;

Arrested preoligodendrocyte maturation contributes to myelination failure in premature infants

Abstract: Objective The major form of MRI-defined white matter injury (WMI) comprises diffuse lesions where the burden of small necrotic foci (microscopic necrosis) is poorly defined We hypothesized that myelination failure associated with diffuse WMI involves an aberrant injury response linked to arrested pre-oligodendrocyte (preOL) maturation in reactive astrocyte-rich lesions

N-Methyl-d-Aspartate Receptor Antibodies in Herpes Simplex Encephalitis

Abstract: Herpes simplex encephalitis (HSE) is the most frequent fatal encephalitis in Western countries.1,2 Despite its substantially improved prognosis since the advent of selective antiviral therapy with acyclovir, about 35% of patients still suffer an unfavorable outcome, with severe neurological residual symptoms or even death.3 However, in patients with HSE, not all symptoms result from direct virus invasion and neuronal cell lysis. The observation of a more severe disease course in immuno-competent as compared to immunocompromised patients suggests a role for secondary autoimmune mechanisms in the pathogenesis of HSE.4 This hypothesis is in line with studies demonstrating a beneficial effect on the outcome when combining acyclovir with corticosteroids.5,6 Additionally, direct viral cytotoxicity is probably not the major pathogenic mechanism in relapses of HSE.7,8 During clinical workup of encephalitis patients, we identified an HSE case that had high-titer immunoglobulin (Ig)A antibodies against N-methyl-d-aspartate receptors (NMDARs), raising the question of whether some symptoms in HSE might be related to secondary immunological phenomena, such as generation of antibodies against neuronal cell surface antigens. These could include prolonged symptoms after acyclovir treatment, the presence of unusual clinical presentations, and the beneficial effect of steroids in some patients. To get an unbiased estimation of the true prevalence of antibodies against a wide range of NMDARs (different subtypes and epitopes) and other synaptic proteins in HSE, we performed a blinded retrospective study analyzing a large archived cohort of consecutive serum and cerebrospinal fluid (CSF) samples from patients with a definite diagnosis of HSE.

Real time quaking-induced conversion analysis of cerebrospinal fluid in sporadic Creutzfeldt–Jakob disease

Abstract: Objective Current cerebrospinal fluid (CSF) tests for sporadic Creutzfeldt-Jakob disease (sCJD) are based on the detection of surrogate markers of neuronal damage such as CSF 14-3-3 which are not specific for sCJD. A number of prion protein conversion assays have been developed, including real-time quaking induced conversion (RT-QuIC). The objective of this study is to investigate whether CSF RT-QuIC analysis could be used as a diagnostic test in sCJD.

Dietary intakes of berries and flavonoids in relation to cognitive decline.

Abstract: Objective: Berries are high in flavonoids, especially anthocyanidins, and improve cognition in experimental studies. We prospectively evaluated whether greater long-term intakes of berries and flavonoids are associated with slower rates of cognitive decline in older women. Methods: Beginning in 1980, a semiquantitative food frequency questionnaire was administered every 4 years to Nurses' Health Study participants. In 1995–2001, we began measuring cognitive function in 16,010 participants, aged ≥70 years; follow-up assessments were conducted twice, at 2-year intervals. To ascertain long-term diet, we averaged dietary variables from 1980 through the initial cognitive interview. Using multivariate-adjusted, mixed linear regression, we estimated mean differences in slopes of cognitive decline by long-term berry and flavonoid intakes. Results: Greater intakes of blueberries and strawberries were associated with slower rates of cognitive decline (eg, for a global score averaging all 6 cognitive tests, for blueberries: p-trend = 0.014 and mean difference = 0.04, 95% confidence interval [CI] = 0.01–0.07, comparing extreme categories of intake; for strawberries: p-trend = 0.022 and mean difference = 0.03, 95% CI = 0.00–0.06, comparing extreme categories of intake), after adjusting for multiple potential confounders. These effect estimates were equivalent to those we found for approximately 1.5 to 2.5 years of age in our cohort, indicating that berry intake appears to delay cognitive aging by up to 2.5 years. Additionally, in further supporting evidence, greater intakes of anthocyanidins and total flavonoids were associated with slower rates of cognitive decline (p-trends = 0.015 and 0.053, respectively, for the global score). Interpretation: Higher intake of flavonoids, particularly from berries, appears to reduce rates of cognitive decline in older adults. ANN NEUROL 2012

Neuron-to-neuron transmission of α-synuclein fibrils through axonal transport

Abstract: Objective: The lesions of Parkinson disease spread through the brain in a characteristic pattern that corresponds to axonal projections. Previous observations suggest that misfolded a-synuclein could behave as a prion, moving from neuron to neuron and causing endogenous a-synuclein to misfold. Here, we characterized and quantified the axonal transport of a-synuclein fibrils and showed that fibrils could be transferred from axons to second-order neurons following anterograde transport. Methods: We grew primary cortical mouse neurons in microfluidic devices to separate somata from axonal projections in fluidically isolated microenvironments. We used live-cell imaging and immunofluorescence to characterize the transport of fluorescent a-synuclein fibrils and their transfer to second-order neurons. Results: Fibrillar a-synuclein was internalized by primary neurons and transported in axons with kinetics consistent with slow component-b of axonal transport (fast axonal transport with saltatory movement). Fibrillar a-synuclein was readily observed in the cell bodies of second-order neurons following anterograde axonal transport. Axon-to-soma transfer appeared not to require synaptic contacts. Interpretation: These results support the hypothesis that the progression of Parkinson disease can be caused by neuron-to-neuron spread of a-synuclein aggregates and that the anatomical pattern of progression of lesions between axonally connected areas results from the axonal transport of such aggregates. That the transfer did not appear to be trans-synaptic gives hope that a-synuclein fibrils could be intercepted by drugs during the extracellular phase of their journey. ANN NEUROL 2012;72:517–524

Prognosis of coma after therapeutic hypothermia: a prospective cohort study.

Abstract: Objective: This study was designed to establish the reliability of neurologic examination, neuron-specific enolase (NSE), and median nerve somatosensory-evoked potentials (SEPs) to predict poor outcome in patients treated with mild hypothermia after cardiopulmonary resuscitation (CPR). Methods: This multicenter prospective cohort study included adult comatose patients admitted to the intensive care unit (ICU) after CPR and treated with hypothermia (32–34 � C). False-positive rates (FPRs 1 � specificity) with their 95% confidence intervals (CIs) were calculated for pupillary light responses, corneal reflexes, and motor scores 72 hours after CPR; NSE levels at admission, 12 hours after reaching target temperature, and 36 hours and 48 hours after collapse; and SEPs during hypothermia and after rewarming. The primary outcome was poor outcome, defined as death, vegetative state, or severe disability (Glasgow Outcome Scale 1–3) after 6 months. Results: Of 391 patients included, 53% had a poor outcome. Absent pupillary light responses (FPR 1; 95% CI, 0–7) or absent corneal reflexes (FPR 4; 95% CI, 1–13) 72 hours after CPR, and absent SEPs during hypothermia (FPR 3; 95% CI, 1–7) and after rewarming (FPR 0; 95% CI, 0–18) were reliable predictors. Motor scores 72 hours after CPR (FPR 10; 95% CI, 6–16) and NSE levels were not. Interpretation: In patients with persisting coma after CPR and therapeutic hypothermia, use of motor score or NSE, as recommended in current guidelines, could possibly lead to inappropriate withdrawal of treatment. Poor outcomes can reliably be predicted by testing brainstem reflexes 72 hours after CPR and performing SEP. ANN NEUROL 2012;71:206–212

Meta-analysis of Parkinson's Disease: Identification of a Novel Locus, RIT2

Abstract: Objective: Genome-wide association (GWAS) methods have identified genes contributing to Parkinson’s disease (PD); we sought to identify additional genes associated with PD susceptibility. Methods: A 2-stage design was used. First, individual level genotypic data from 5 recent PD GWAS (Discovery Sample: 4,238 PD cases and 4,239 controls) were combined. Following imputation, a logistic regression model was employed in each dataset to test for association with PD susceptibility and results from each dataset were metaanalyzed. Second, 768 single-nucleotide polymorphisms (SNPs) were genotyped in an independent Replication Sample (3,738 cases and 2,111 controls). Results: Genome-wide significance was reached for SNPs in SNCA (rs356165; G: odds ratio [OR] ¼ 1.37; p ¼ 9.3 � 10 � 21 ), MAPT (rs242559; C: OR ¼ 0.78; p ¼ 1.5 � 10 � 10 ), GAK/DGKQ (rs11248051; T: OR ¼ 1.35; p ¼ 8.2 � 10 � 9 / rs11248060; T: OR ¼ 1.35; p ¼ 2.0 � 10 � 9 ), and the human leukocyte antigen (HLA) region (rs3129882; A: OR ¼ 0.83; p ¼ 1.2 � 10 � 8 ), which were previously reported. The Replication Sample confirmed the associations with SNCA, MAPT, and the HLA region and also with GBA (E326K; OR ¼ 1.71; p ¼ 5 � 10 � 8 Combined Sample) (N370; OR ¼ 3.08; p ¼ 7 � 10 � 5 Replication sample). A novel PD susceptibility locus, RIT2, on chromosome 18 (rs12456492; p ¼ 5 � 10 � 5 Discovery Sample; p ¼ 1.52 � 10 � 7 Replication sample; p ¼ 2 � 10 � 10 Combined Sample) was replicated. Conditional analyses within each of the replicated regions identified distinct SNP associations within GBA and SNCA, suggesting that there may be multiple risk alleles within these genes. Interpretation: We identified a novel PD susceptibility locus, RIT2, replicated several previously identified loci, and identified more than 1 risk allele within SNCA and GBA. ANN NEUROL 2012;71:370–384

miR-206 regulates brain-derived neurotrophic factor in Alzheimer disease model

Abstract: Objective: Alzheimer disease (AD) brains are deficient in brain-derived neurotrophic factor (BDNF), which regulates synaptic plasticity and memory. MicroRNAs (miRNAs) are ∼22-nucleotide small noncoding RNAs that control a variety of physiological and disease processes. Here, we show that miR-206 regulates BDNF and memory function in AD mice. Methods: Expression of miRNAs was analyzed in Tg2576 AD transgenic mice and human AD brain samples. Regulation of BDNF by a selected miRNA was validated by in silico prediction, target gene luciferase assay, and dendritic spine responses in neurons. AM206, a neutralizing inhibitor of miR-206 (antagomir), was injected into the third ventricle of Tg2576 mice, after which memory function, synaptogenesis, neurogenesis, and target gene expression were assessed. For noninvasive delivery, antagomirs were administered intranasally. Results: The brains of Tg2576 mice and the temporal cortex of human AD brains had increased levels of miR-206. This miRNA targeted BDNF transcripts, and AM206 prevented the detrimental effects of amyloid-β42 on BDNF and dendritic spine degeneration in Tg2576 neurons. Injection of AM206 into the cerebral ventricles of AD mice increased the brain levels of BDNF and improved their memory function. In parallel, AM206 enhanced the hippocampal synaptic density and neurogenesis. Furthermore, intranasally administered AM206 also reached the brain and increased BDNF levels and memory function in AD mice. Interpretation: Our findings demonstrate a novel miRNA-dependent regulation of BDNF in AD and suggest possible therapeutic approaches, such as noninvasive intranasal delivery of AM206. ANN NEUROL 2012;72:269–277.

Myeloid microvesicles are a marker and therapeutic target for neuroinflammation

Abstract: Objective: Microvesicles (MVs) have been indicated as important mediators of intercellular communication and are emerging as new biomarkers of tissue damage Our previous data indicate that reactive microglia/macrophages release MVs in vitro The aim of the study was to evaluate whether MVs are released by microglia/macrophages in vivo and whether their number varies in brain inflammatory conditions, such as multiple sclerosis (MS) Methods: Electron and fluorescence microscopy and flow cytometry were used to detect myeloid MVs in the cerebrospinal fluid (CSF) of healthy controls, MS patients, and rodents affected by experimental autoimmune encephalomyelitis (EAE), the animal model of MS Results: Myeloid MVs were detected in CSF of healthy controls In relapsing and remitting EAE mice, the concentration of myeloid MVs in the CSF was significantly increased and closely associated with disease course Analysis of MVs in the CSF of 28 relapsing patients and 28 patients with clinical isolated syndrome from 2 independent cohorts revealed higher levels of myeloid MVs than in 13 age-matched controls, indicating a clinical value of MVs as a companion tool to capture disease activity Myeloid MVs were found to spread inflammatory signals both in vitro and in vivo at the site of administration; mice impaired in MV shedding were protected from EAE, suggesting a pathogenic role for MVs in the disease Finally, FTY720, the first approved oral MS drug, significantly reduced the amount of MVs in the CSF of EAE-treated mice Interpretation: These findings identify myeloid MVs as a marker and therapeutic target of brain inflammation ANN NEUROL 2012;72:610–624

Aquaporin 4-Specific T Cells in Neuromyelitis Optica Exhibit a Th17 Bias and Recognize Clostridium ABC Transporter

Abstract: Neuromyelitis optica (NMO) is a rare, disabling, sometimes fatal, central nervous system (CNS) demyelinating disease characterized by severe attacks of optic neuritis and transverse myelitis.1 NMO is considered to be primarily a humoral autoimmune disease, as a majority of NMO patients develop autoantibodies (NMO immunoglobulin [Ig]G) against aquaporin 4 (AQP4),2 the predominant CNS water channel, which is abundantly expressed on astrocytes. AQP4-specific antibodies in NMO serum are IgG1, a subclass of mature IgG that requires help from T cells,3 indicating that AQP4-specific CD4+ T cells participate in the genesis of this adaptive humoral response. Passive transfer of AQP4-specific antibodies alone did not produce CNS pathology, but did promote development of NMO-like lesions in recipient animals when CNS inflammation was induced by myelin-specific T cells.4, 5 T cells are detected within active NMO lesions.6 Further, NMO lesions are characterized by an abundance of eosinophils and neutrophils, and elevated levels of IL-17 have been associated with NMO,7 suggesting involvement of Th17 cells. However, as no previous studies have identified or characterized proliferative AQP4-specific T cells in NMO patients, their potential role in NMO pathogenesis is largely unknown. In this report, we first identified peripheral blood T cells from NMO patients and healthy controls (HC) that proliferated in response to discrete AQP4 peptides or intact AQP4. T cells from NMO patients demonstrated greater proliferation to this autoantigen than those from HC, and responded most frequently to p61–80. After defining the p61–80 core T-cell determinant, residues 63–76, we conducted a homology search with known microbes. We discovered that AQP4 p63–76 contains strong homology to aa 204–217 of an adenosine triphosphate-binding cassette (ABC) transporter permease of Clostridium perfringens, a bacterial species that contains both commensal and pathogenic strains for humans. T cells from NMO patients responded to the homologous ABC transporter peptide and exhibited cross-reactivity between this foreign antigen and AQP4 p63–76, findings that support molecular mimicry. When compared to HC, AQP4 p61–80-specific T cells from NMO patients exhibited Th17 polarization. Monocytes from NMO patients produced significantly higher levels of the Th17-polarizing cytokine interleukin (IL)-6, suggesting that immunologic dysfunction in NMO may also include the innate immune compartment. Collectively, our findings establish that AQP4-specific proliferative T cells exist, and support a Th17 bias in the adaptive immune response in NMO. Our demonstration of T-cell molecular mimicry may stimulate further evaluation of the potential role of the Clostridium species in NMO pathogenesis.

Neonatal Encephalopathy: An Inadequate Term for Hypoxic-Ischemic Encephalopathy

Abstract: This Point of View article addresses neonatal encephalopathy (NE) presumably caused by hypoxia-ischemia and the terminology currently in wide use for this disorder. The nonspecific term NE is commonly utilized for those infants with the clinical and imaging characteristics of neonatal hypoxic-ischemic encephalopathy (HIE). Multiple magnetic resonance imaging studies of term infants with the clinical setting of presumed hypoxia-ischemia near the time of delivery have delineated a topography of lesions highly correlated with that defined by human neuropathology and by animal models, including primate models, of hypoxia-ischemia. These imaging findings, coupled with clinical features consistent with perinatal hypoxic-ischemic insult(s), warrant the specific designation of neonatal HIE.

Coordinated reset has sustained aftereffects in Parkinsonian monkeys

Abstract: Coordinated reset neuromodulation consists of the application of consecutive brief high-frequency pulse trains through the different contacts of the stimulation electrode. In theoretical studies, by achieving unlearning of abnormal connectivity between neurons, coordinated reset neuromodulation reduces pathological synchronization, a hallmark feature of Parkinson's disease pathophysiology. Here we show that coordinated reset neuromodulation of the subthalamic nucleus has both acute and sustained long-lasting aftereffects on motor function in parkinsonian nonhuman primates. Long-lasting aftereffects were not observed with classical deep brain stimulation. These observations encourage further development of coordinated reset neuromodulation for treating motor symptoms in Parkinson disease patients.

A role for the default mode network in the bases of disorders of consciousness

Abstract: Objective: Functional connectivity in the default mode network (DMN) is known to be reduced in patients with disorders of consciousness, to a different extent depending on their clinical severity. Nevertheless, the integrity of the structural architecture supporting this network and its relation with the exhibited functional disconnections are very poorly understood. We investigated the structural connectivity and white matter integrity of the DMN in patients with disorders of consciousness of varying clinical severity. Methods: Fifty-two patients—19 in a vegetative state (VS), 27 in a minimally conscious state (MCS), and 6 emerging from a minimally conscious state (EMCS)—and 23 healthy volunteers participated in the study. Structural connectivity was assessed by means of probabilistic tractography, and the integrity of the resulting fibers was characterized by their mean fractional anisotropy values. Results: Patients showed significant impairments in all of the pathways connecting cortical regions within this network, as well as the pathway connecting the posterior cingulate cortex/precuneus with the thalamus, relative to the healthy volunteers. Moreover, the structural integrity of this pathway, as well as that of those connecting the posterior areas of the network, was correlated with the patients’ behavioral signs for awareness, being higher in EMCS patients than those in the upper and lower ranges of the MCS patients, and lowest in VS patients. Interpretation: These results provide a possible neural substrate for the functional disconnection previously described in these patients, and reinforce the importance of the DMN in the genesis of awareness and the neural bases of its disorders. ANN NEUROL 2012;72:335–343

Macrophages prevent hemorrhagic infarct transformation in murine stroke models

Abstract: Objective: Inflammation is increasingly viewed as a new therapeutic target in subacute stages of brain infarction. However, apart from causing secondary damage, inflammation could equally promote beneficial lesion remodeling and repair. Distinct subpopulations of monocytes/macrophages (MOs/MPs) may critically determine the outcome of lesion-associated inflammation. Methods: We addressed the role of bone marrow-derived MOs/MPs in 2 different mouse models of ischemic stroke using a combined cell-specific depletion, chemokine receptor knockout, bone marrow chimeric, and pharmacological approach. Results: Starting within 24 hours of stroke onset, immature Ly6chi monocytes infiltrated into the infarct border zone and differentiated into mature Ly6clo phagocytes within the lesion compartment. MO/MP infiltration was CCR2-dependent, whereas we did not obtain evidence for additional recruitment via CX3CR1. Depletion of circulating MOs/MPs or selective targeting of CCR2 in bone marrow-derived cells caused delayed clinical deterioration and hemorrhagic conversion of the infarctions. Bleeding frequently occurred around thin-walled, dilated neovessels in the infarct border zone and was accompanied by decreased expression of transforming growth factor (TGF)-β1 and collagen-4, along with diminished activation of Smad2. Injection of TGF-β1 into the lesion border zone greatly reduced infarct bleeding in MO/MP-depleted mice. Interpretation: Bone marrow-derived MOs/MPs recruited via CCR2 and acting via TGF-β1 are essential for maintaining integrity of the neurovascular unit following brain ischemia. Future therapies should be aimed at enhancing physiological repair functions of CCR2+ MOs/MPs rather than blocking their hematogenous recruitment. ANN NEUROL 2012;71:743–752

Anti-aquaporin-4 monoclonal antibody blocker therapy for neuromyelitis optica.

Abstract: Objective: Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system. Circulating autoantibodies (NMO-immunoglobulin [Ig]G) against astrocyte water channel aquaporin-4 (AQP4) cause complement- and cell-mediated astrocyte damage with consequent neuroinflammation and demyelination. Current NMO therapies, which have limited efficacy, include immunosuppression and plasma exchange. The objective of this study was to develop a potential new NMO therapy based on blocking of pathogenic NMO-IgG binding to its target, AQP4. Methods: We generated nonpathogenic recombinant monoclonal anti-AQP4 antibodies that selectively block NMO-IgG binding to AQP4. These antibodies comprise a tight-binding anti-AQP4 Fab and a mutated Fc that lacks functionality for complement- and cell-mediated cytotoxicity. The efficacy of the blocking antibodies was studied using cell culture, spinal cord slice, and in vivo mouse models of NMO. Results: In AQP4-expressing cell cultures, the nonpathogenic competing antibodies blocked binding of NMO-IgG in human sera, reducing to near zero complement- and cell-mediated cytotoxicity. The antibodies prevented the development of NMO lesions in an ex vivo spinal cord slice model of NMO and in an in vivo mouse model, without causing cytotoxicity. Interpretation: Our results provide proof of concept for a therapy of NMO with blocking antibodies. The broad efficacy of antibody inhibition is likely due to steric competition because of its large physical size compared to AQP4. Blocker therapy to prevent binding of pathogenic autoantibodies to their targets may be useful for treatment of other autoimmune diseases as well. ANN NEUROL 2012;

Isoflurane-induced apoptosis of oligodendrocytes in the neonatal primate brain

Abstract: Objective Previously we reported that exposure of 6-day old (P6) rhesus macaques to isoflurane for 5 hours triggers a robust neuroapoptosis response in developing brain. We have also observed (unpublished) that isoflurane causes apoptosis of cellular profiles in the white matter that resemble glia. We analyzed the cellular identity of the apoptotic white matter profiles and determined the magnitude of this cell death response to isoflurane.