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Background and purpose: The validity, reliability, and longitudinal performance of the Patient‐Determined Disease Steps (PDDS) scale is unknown in people with multiple sclerosis (MS) with mild to moderate disability. We aimed to examine the psychometric properties and longitudinal performance of the PDDS. Methods: We included relapsing–remitting MS patients with an Expanded Disability Status Scale (EDSS) score of less than 4. Validity and test–retest reliability was examined. Longitudinal data were analysed with mixed‐effect modelling and Cohen's kappa for concordance in confirmed disability progression (CDP). Results: We recruited a total of 1093 participants, of whom 904 had complete baseline data. The baseline correlation between PDDS and EDSS was weak (ρ = 0.45, p < 0.001). PDDS had stronger correlations with patient‐reported outcomes (PROs). Conversely, EDSS had stronger correlations with age, disease duration, Kurtzke's functional systems and processing speed test. PDDS test–retest reliability was good to excellent (concordance correlation coefficient = 0.73–0.89). Longitudinally, PDDS was associated with EDSS, age and depression. A higher EDSS score was associated with greater PDSS progression. The magnitude of these associations was small. There was no concordance in CDP as assessed by PDDS and EDSS. Conclusion: The PDDS has greater correlation with other PROs but less correlation with other MS‐related outcome measures compared to the EDSS. There was little correlation between PDDS and EDSS longitudinally. Our findings suggest that the PDDS scale is not interchangeable with the EDSS. [ABSTRACT FROM AUTHOR]

Background and purpose: Understanding predictors of changes in employment status among people living with multiple sclerosis (MS) can assist health care providers to develop appropriate work retention/rehabilitation programs. We aimed to model longitudinal transitions of employment status in MS and estimate the probabilities of retaining employment status or losing or gaining employment over time in individuals with a first clinical diagnosis of central nervous system demyelination (FCD). Methods: This prospective cohort study comprised adults (aged 18–59 years) diagnosed with FCD (n = 237) who were followed for more than 11 years. At each review, participants were assigned to one of three states: unemployed, part‐time, or full‐time employed. A Markov multistate model was used to examine the rate of state‐to‐state transitions. Results: At the time of FCD, participants with full‐time employment had an 89% chance of being in the same state over a 1‐year period, but this decreased to 42% over the 10‐year follow‐up period. For unemployed participants, there was a 92% likelihood of remaining unemployed after 1 year, but this probability decreased to 53% over 10 years. Females, those who progressed to clinically definite MS, those with a higher relapse count, and those with a greater level of disability were at increased risk of transitioning to a deteriorated employment state. In addition, those who experienced clinically significant fatigue over the follow‐up period were less likely to gain employment after being unemployed. Conclusions: In our FCD cohort, we found a considerable rate of employment transition during the early years post‐diagnosis. Over more than a decade of follow‐up post‐FCD, we found that females and individuals with a greater disability and a higher relapse count are at higher risk of losing employment. [ABSTRACT FROM AUTHOR]

Background and purpose: Epstein–Barr virus (EBV) is implicated in multiple sclerosis (MS) risk; evidence for other herpesviruses is inconsistent. Here, we test blood markers of infection with human herpesvirus 6 (HHV‐6), varicella zoster virus (VZV), and cytomegalovirus (CMV) as risk factors for a first clinical diagnosis of central nervous system demyelination (FCD) in the context of markers of EBV infection. Methods: In the Ausimmune case–control study, cases had an FCD, and population controls were matched on age, sex, and study region. We quantified HHV‐6‐ and VZV‐DNA load in whole blood and HHV‐6, VZV, and CMV antibodies in serum. Conditional logistic regression tested associations with FCD risk, adjusting for Epstein–Barr nuclear antigen (EBNA) IgG, EBV‐DNA load, and other covariates. Results: In 204 FCD cases and 215 matched controls, only HHV‐6‐DNA load (positive vs. negative) was associated with FCD risk (adjusted odds ratio = 2.20, 95% confidence interval = 1.08–4.46, p = 0.03). Only EBNA IgG and HHV‐6‐DNA positivity were retained in a predictive model of FCD risk; the combination had a stronger association than either alone. CMV‐specific IgG concentration modified the association between an MS risk‐related human leucocyte antigen gene and FCD risk. Six cases and one control had very high HHV‐6‐DNA load (>1.0 × 106 copies/mL). Conclusions: HHV‐6‐DNA positivity and high load (possibly due to inherited HHV‐6 chromosomal integration) were associated with increased FCD risk, particularly in association with markers of EBV infection. With growing interest in prevention/management of MS through EBV‐related pathways, there should be additional consideration of the role of HHV‐6 infection. [ABSTRACT FROM AUTHOR]

Upper and lower limb impairments are common in people with multiple sclerosis (pwMS), yet difficult to clinically identify in early stages of disease progression. Tasks involving complex motor control can potentially reveal more subtle deficits in early stages, and can be performed during functional MRI (fMRI) acquisition, to investigate underlying neural mechanisms, providing markers for early motor progression. We investigated brain activation during visually guided force matching of hand or foot in 28 minimally disabled pwMS (Expanded Disability Status Scale (EDSS) < 4 and pyramidal and cerebellar Kurtzke Functional Systems Scores ≤ 2) and 17 healthy controls (HC) using ultra‐high field 7‐Tesla fMRI, allowing us to visualise sensorimotor network activity in high detail. Task activations and performance (tracking lag and error) were compared between groups, and correlations were performed. PwMS showed delayed (+124 s, p =.002) and more erroneous (+0.15 N, p =.001) lower limb tracking, together with lower cerebellar, occipital and superior parietal cortical activation compared to HC. Lower activity within these regions correlated with worse EDSS (p =.034), lower force error (p =.006) and higher lesion load (p <.05). Despite no differences in upper limb task performance, pwMS displayed lower inferior occipital cortical activation. These results demonstrate that ultra‐high field fMRI during complex hand and foot tracking can identify subtle impairments in lower limb movements and upper and lower limb brain activity, and differentiates upper and lower limb impairments in minimally disabled pwMS. [ABSTRACT FROM AUTHOR]

Objective: Primary progressive multiple sclerosis (PPMS) causes accumulation of neurological disability from disease onset without clinical attacks typical of relapsing multiple sclerosis (RMS). However, whether genetic variation influences the disease course remains unclear. We aimed to determine whether mutations causative of neurological disorders that share features with multiple sclerosis (MS) contribute to risk for developing PPMS.Methods: We examined whole-genome sequencing (WGS) data from 38 PPMS and 81 healthy subjects of European ancestry. We selected pathogenic variants exclusively found in PPMS patients that cause monogenic neurological disorders and performed two rounds of replication genotyping in 746 PPMS, 3,049 RMS, and 1,000 healthy subjects. To refine our findings, we examined the burden of rare, potentially pathogenic mutations in 41 genes that cause hereditary spastic paraplegias (HSPs) in PPMS (n = 314), secondary progressive multiple sclerosis (SPMS; n = 587), RMS (n = 2,248), and healthy subjects (n = 987) genotyped using the MS replication chip.Results: WGS and replication studies identified three pathogenic variants in PPMS patients that cause neurological disorders sharing features with MS: KIF5A p.Ala361Val in spastic paraplegia 10; MLC1 p.Pro92Ser in megalencephalic leukodystrophy with subcortical cysts, and REEP1 c.606 + 43G>T in Spastic Paraplegia 31. Moreover, we detected a significant enrichment of HSP-related mutations in PPMS patients compared to controls (risk ratio [RR] = 1.95; 95% confidence interval [CI], 1.27-2.98; p = 0.002), as well as in SPMS patients compared to controls (RR = 1.57; 95% CI, 1.18-2.10; p = 0.002). Importantly, this enrichment was not detected in RMS.Interpretation: This study provides evidence to support the hypothesis that rare Mendelian genetic variants contribute to the risk for developing progressive forms of MS. Ann Neurol 2018;83:51-63. [ABSTRACT FROM AUTHOR]

The article discusses a study which reviewed several Phase III clinical trials and Cochrane reviews on treatments for multiple sclerosis (MS) across New Zealand and Australia. Topics covered include analysis of levels of efficacies in various therapies, relapsing-remitting MS and risks for progressive multifocal leukoencephalopathy (PML) with natalizumab. Findings showed association of MS therapies with lymphopenia, development of idiopathic thrombocytopenic purpura (ITP) and thyroid disease.

Cognitive dysfunction is common in patients with multiple sclerosis (MS). Saccadic eye movement paradigms such as antisaccades (AS) can sensitively interrogate cognitive function, in particular, the executive and attentional processes of response selection and inhibition. Although we have previously demonstrated significant deficits in the generation of AS in MS patients, the neuropathological changes underlying these deficits were not elucidated. In this study, 24 patients with relapsing-remitting MS underwent testing using an AS paradigm. Rank correlation and multiple regression analyses were subsequently used to determine whether AS errors in these patients were associated with: (i) neurological and radiological abnormalities, as measured by standard clinical techniques, (ii) cognitive dysfunction, and (iii) regionally specific cerebral white and gray-matter damage. Although AS error rates in MS patients did not correlate with clinical disability (using the Expanded Disability Status Score), T2 lesion load or brain parenchymal fraction, AS error rate did correlate with performance on the Paced Auditory Serial Addition Task and the Symbol Digit Modalities Test, neuropsychological tests commonly used in MS. Further, voxel-wise regression analyses revealed associations between AS errors and reduced fractional anisotropy throughout most of the cerebellum, and increased mean diffusivity in the cerebellar vermis. Region-wise regression analyses confirmed that AS errors also correlated with gray-matter atrophy in the cerebellum right VI subregion. These results support the use of the AS paradigm as a marker for cognitive dysfunction in MS and implicate structural and microstructural changes to the cerebellum as a contributing mechanism for AS deficits in these patients. Hum Brain Mapp 35:2310-2319, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The expression of the neurotrophins and their receptors is essential for peripheral nervous system development and myelination. We have previously demonstrated that brain-derived neurotrophic factor (BDNF) exerts contrasting influences upon Schwann cell myelination in vitro - promoting myelination via neuronally expressed p75NTR, but inhibiting myelination via neuronally expressed TrkB. We have generated a small peptide called cyclo- dPAKKR that structurally mimics the region of BDNF that binds p75NTR. Here, we have investigated whether utilizing cyclo- dPAKKR to selectively target p75NTR is an approach that could exert a unified promyelinating response. Like BDNF, cyclo- dPAKKR promoted myelination of nerve growth factor-dependent neurons in vitro, an effect dependent on the neuronal expression of p75NTR. Importantly, cyclo- dPAKKR also significantly promoted the myelination of tropomyosin-related kinase receptor B-expressing neurons in vitro, whereas BDNF exerted a significant inhibitory effect. This indicated that while BDNF exerted a contrasting influence upon the myelination of distinct subsets of dorsal root ganglion (DRG) neurons in vitro, cyclo- dPAKKR uniformly promoted their myelination. Local injection of cyclo- dPAKKR adjacent to the developing sciatic nerve in vivo significantly enhanced myelin protein expression and significantly increased the number of myelinated axons. These results demonstrate that cyclo- dPAKKR promotes peripheral myelination in vitro and in vivo, suggesting it is a strategy worthy of further investigation for the treatment of peripheral demyelinating diseases. [ABSTRACT FROM AUTHOR]

Introduction Multiple sclerosis ( MS) is a debilitating disease that causes significant morbidity within a young demographic. Diagnostic guidelines for MS have evolved, and imaging has played an increasingly important role in diagnosis over the last two decades. For imaging to contribute to diagnosis in a meaningful way, it must be reproducible. Consensus guidelines for MRI in MS exist to define correct sequence type and imaging technique, but it is not clear to what extent they are followed. This study reviewed MRI studies performed on Australian individuals presenting with a first clinical diagnosis of central nervous system demyelination ( FCD) for adherence to published guidelines and discussed practical implementation of MS guidelines in light of recent updates. Methods The Ausimmune study was a prospective case control study of Australian participants presenting with FCD from 2003 to 2006. Baseline cranial and spinal cord MRI studies of 226 case participants from four separate Australian regions were reviewed. MRI sequences were classified according to anatomical location, slice plane, tissue weighting and use of gadolinium-containing contrast media. Results were compared with the 2003 Consortium of Multiple Sclerosis Centres MRI protocol for the diagnosis of MS. Results The composition of core cranial MRI sequences performed varied across the 226 scans. Of the studies, 91% included sagittal fluid attenuated inversion recovery ( FLAIR) sequences. Cranial axial T2-weighted, axial FLAIR and axial proton density-weighted sequences were performed in 88%, 60% and 16% (respectively) of scans. Only 25% of the studies included a T1-weighted contrast-enhanced sequence. Concordance with the guidelines in all sequences was very low (2). Conclusion Only a small number of MRI investigations performed included all of the sequences stipulated by consensus guidelines. This is likely due to poor awareness in the imaging community of the guidelines and the rationale behind certain sequences. Radiologists with a sub-speciality interest in neuroradiology should take ownership of this issue and ensure that recommended imaging guidelines are followed. [ABSTRACT FROM AUTHOR]

J. Neurochem. (2012) 122, 1167-1180. Abstract Multiple extracellular factors have been implicated in orchestrating myelination of the CNS; however, less is known about the intracellular signaling cascades that regulate this process. We have previously shown that brain-derived neurotrophic factor (BDNF) promotes oligodendrocyte myelination. Here, we screened for the activation of candidate signaling pathways in in vitro myelination assays and found that extracellular signal-regulated kinase (Erk) signaling positively correlated with basal levels of oligodendrocyte myelination as well as BDNF-induced myelination in vitro. By selectively manipulating Erk1/2 activation in oligodendrocytes in vitro, we found that constitutive activation of Erk1/2 significantly increased myelination, mimicking the promyelinating effect of BDNF, and also caused myelination to occur earlier. Conversely, selective inhibition of Erk1/2 in oligodendrocytes significantly reduced the basal level of myelination and blocked the promyelinating effect of BDNF. Analysis of myelinating spinal cord and corpus callosum white matter tracts revealed that the majority of mature oligodendrocytes are co-labeled with phospho-Erk1/2, whereas phospho-Erk1/2 was rarely observed in oligodendrocyte progenitor cells. Finally, the total level of phospho-Erk1/2 correlated with myelin formation during the early postnatal period. Collectively, these data identify that Erk1/2 signaling within oligodendrocytes exerts an important and direct effect to promote myelination. [ABSTRACT FROM AUTHOR]

Trans-synaptic degeneration could exacerbate neurodegeneration in multiple sclerosis (MS). We aimed to assess whether anterograde trans-synaptic degeneration could be identified in the primary visual pathway in vivo. Diffusion tensor imaging (DTI) was used to assess the optic radiations in 15 patients with previous optic nerve inflammation and 9 healthy volunteers. A probabilistic atlas of the optic radiations was created from healthy diffusion tractography data. Lengthwise profiles for DTI parameters (axial [λ||], radial [λ⟂] and mean diffusivity [MD], fractional anisotropy [FA] and the angle of deviation of the principal eigenvector [α]) were analyzed for patients and controls. Patients also underwent multifocal visual evoked potential (mfVEP) assessments to characterize the latency and amplitude of cortical potentials. Correlations were performed between mfVEP latency and amplitude in the left and right visual hemi-fields and DTI parameters in the contra-lateral optic radiations. Patients displayed a significant decrease in λ|| within the body of both optic radiations, which significantly correlated with loss of mfVEP amplitude. Abnormal λ⟂ and FA were detected bilaterally throughout the optic radiations in patients but the abnormality was not associated with amplitude reduction or latency prolongation of the mfVEP. An abnormal α value was observed in the left optic radiations of patients, and the α value in the body of the optic radiations also correlated with mfVEP amplitude loss. The assocation between bilateral DTI abnormalities within the optic radiations and loss of afferent electrical activity could indicate anterograde trans-synaptic degeneration occurs following optic neuritis. Hum Brain Mapp 33:2047-2061, 2012. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Observations of increasing allergy prevalence with decreasing distance from the Equator and positive associations with ambient ultraviolet radiation have contributed to a growing interest in the possible role of vitamin D in the etiology of allergy. The aims of this study were to describe any latitudinal variation in the prevalence of childhood allergy in Australia and to evaluate, in parallel, the individual associations between ultraviolet radiation (UVR)- and vitamin D-related measures and hayfever asthma and both conditions. Participants were population-based controls who took part in a multicenter case-control study, aged 18-61 yr and resident in one of four study regions ranging in latitude from 27°S to 43°S. Data were derived from a self-administered questionnaire, interview and examination by a research officer and biologic sampling. Latitude and longitude coordinates were geocoded from participants' residential locations and climatic data were linked to postcodes of current residence. Stored serum was analyzed for 25-hydroxyvitamin D concentrations and silicone rubber casts of the skin were used as an objective measure of cumulative actinic damage. There was an inverse latitude gradient for asthma (a 9% decrease per increasing degree of latitude); however, this pattern did not persist after adjusting for average daily temperature. There was no association between any of the UVR- or vitamin D-related measures and childhood asthma, but greater time in the sun in winter between the ages 6-15 yr was associated with an increase in the odds of having hayfever [adjusted odds ratios (OR) 1.29; 95% CI 1.01-1.63]. Oral supplementation with cod liver oil in childhood increased the odds of a history of having both asthma and hayfever (2.87; 1.00-8.32). Further investigation of the possible role of early vitamin D supplementation in the development of allergy is warranted. Our results also suggest that solar exposure during childhood may be important in allergic sensitization. Plausible explanations, including biologic mechanisms, exist for both observations. [ABSTRACT FROM AUTHOR]

J. Neurochem. (2010) 115, 11-22. The adult subventricular zone (SVZ) is a potential source of precursor cells to replace neural cells lost during demyelination. To better understand the molecular events that regulate neural precursor cell responsiveness in this context we undertook a microarray and quantitative PCR based analysis of genes expressed within the SVZ during cuprizone-induced demyelination. We identified an up-regulation of the genes encoding bone morphogenic protein 4 (BMP4) and its receptors. Immunohistochemistry confirmed an increase in BMP4 protein levels and also showed an increase in phosphorylated SMAD 1/5/8, a key component of BMP4 signalling, during demyelination. In vitro analysis revealed that neural precursor cells isolated from demyelinated animals, as well as those treated with BMP4, produce more astrocytes. Similarly, there were increased numbers of astrocytes in vivo within the SVZ during demyelination. Intraventricular infusion of Noggin, an endogenous antagonist of BMP4, during cuprizone-induced demyelination reduced pSMAD1/5/8, decreased astrocyte numbers and increased oligodendrocyte numbers in the SVZ. Our results suggest that lineage commitment of SVZ neural precursor cells is altered during demyelination and that BMP signalling plays a role in this process. [ABSTRACT FROM AUTHOR]

The neurotrophin receptor homolog (NRH2) is closely related to the p75 neurotrophin receptor (p75NTR); however, its function and role in neurotrophin signaling are unclear. NRH2 does not bind to nerve growth factor (NGF), however, is able to form a receptor complex with tropomyosin-related kinase receptor A (TrkA) and to generate high-affinity NGF binding sites. Despite this, the mechanisms underpinning the interaction between NRH2 and TrkA remain unknown. Here, we identify that the intracellular domain of NRH2 is required to form an association with TrkA. Our data suggest extensive intracellular interaction between NRH2 and TrkA, as either the juxtamembrane or death domain regions of NRH2 are sufficient for interaction with TrkA. In addition, we demonstrate that TrkA signaling is dramatically influenced by the co-expression of NRH2. Importantly, NRH2 did not influence all downstream TrkA signaling pathways, but rather exerted a specific effect, enhancing src homology 2 domain-containing transforming protein (Shc) activation. Moreover, downstream of Shc, the co-expression of NRH2 resulted in TrkA specifically modulating mitogen-activated protein kinase pathway activation, but not the phosphatidylinositol 3-kinase/Akt pathway. These results indicate that NRH2 utilizes intracellular mechanisms to not only regulate NGF binding to TrkA, but also specifically modulate TrkA receptor signaling, thus adding further layers of complexity and specificity to neurotrophin signaling. [ABSTRACT FROM AUTHOR]

Purpose To characterize and compare histological and MRI-based changes within the corpus callosum (CC) in the cuprizone mouse model of multiple sclerosis (MS). Materials and Methods A total of 12 C57/BL6 mice were fed cuprizone from eight weeks of age for four weeks. One cohort of six cuprizone and two control mice were scanned with a T2-weighted (T2W) sequence. The other cohort of six cuprizone and four control mice were scanned using a dual-echo sequence for T2-mapping and a diffusion-weighted sequence with two orthogonal diffusion encoding directions to calculate water diffusivities parallel and perpendicular to the CC fiber (apparent diffusion coefficients [ADC]∥ and ADC⟂). After the mice were killed, the rostral-caudal pattern of CC demyelination and other pathologies were examined using Luxol Fast Blue, neurofilament staining, and immunohistochemistry for microglia and were correlated with MRI. Results In contrast to control mice, T2W imaging (T2WI) hyperintensity, reduced ADC∥, and elevated ADC⟂ were detected in the CC of cuprizone-fed mice, particularly in the caudal segment. The T2 value was increased in the entire CC. Marked demyelination, as well as axonal injury, microglia accumulation, and cellular infiltration were found in the caudal section of the cuprizone mouse CC. The rostral-caudal pattern of abnormalities within the CC in MRI measurements correlated well with histopathological findings. Conclusion Noninvasive MRI using quantitative T2 and ADC mapping accurately characterized the rostral-caudal pattern of CC demyelination and other pathologies in cuprizone challenged mice, and thus could provide an effective way to assess the structural response to experimental therapeutics being designed for the treatment of MS. J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Schwann cells play a major role in promoting nerve survival and regeneration after injury. Their activities include providing neurotrophic factors and increasing the production of extracellular matrix components and cell surface adhesion molecules to promote axon regeneration. Following nerve transection, leukemia inhibitory factor (LIF) is up-regulated by Schwann cells at the injury site. LIF receptors are also up-regulated at the nerve injury site, but their cellular localization and function have not been fully characterized. We demonstrate that Schwann cells express mRNAs for LIF and the LIF receptor components LIF receptor subunit β and glycoprotein 130 in vitro. We also show that although LIF is not required for the genesis of Schwann cells, it can potentiate the survival of differentiated Schwann cells in the context of neuregulin support. Not only does exogenous LIF promote survival under these conditions, but addition of the soluble LIF receptor (LIF binding protein) and anti-LIF antibodies significantly reduced cell survival, suggesting that LIF exerts autocrine effects. These results suggest that Schwann cell survival following nerve injury is potentially modulated by LIF. [ABSTRACT FROM AUTHOR]

In the developing forebrain, mounting evidence suggests that neural stem cell proliferation and differentiation is regulated by growth factors. In vitro in the presence of serum, stem cell proliferation is predominantly mediated by fibroblast growth factor-2 (FGF-2) whereas neuronal differentiation can be triggered by FGF-1 in association with a specific heparan sulphate proteoglycan. On the other hand, astrocyte differentiation in vivo and in vitro appears to be dependent on signalling through the leukaemia inhibitory factor receptor (LIFR). The evidence suggests that in the absence of LIFR signalling, the stem cell population is present at approximately the same frequency and can generate neurons but is blocked from producing astrocytes that express glial fibrillary acidic protein (GFAP) or have trophic functions. The block can be overcome by other growth factors such as BMP-2/4 or interferon-γ, providing further evidence that the inhibition to astrocyte development does not result from loss of a precursor population. Signalling through the LIFR, in addition to stimulating astrocyte differentiation, may also inhibit neuronal differentiation, which may explain why this receptor is expressed at the earliest stages of neurogenesis. Another signalling system which also exerts its influence on neurogenesis through active inhibition is Delta-Notch. We show in vitro that at high cell densities which impede neuronal production by FGF-1, lowering the levels of expression of the receptor Notch by antisense oligonucleotide results in a significant increase in neuronal production. Thus, stem cell differentiation appears to be dependent on the outcome of interactions between a number of signalling pathways, some which promote specific lineages and some which inhibit. [ABSTRACT FROM AUTHOR]