Jackie Palace

Quantitative pathological evidence for axonal loss in normal appearing white matter in multiple sclerosis.

We assessed axonal loss in the normal appearing white matter of the corpus callosum in postmortem brains of patients with multiple sclerosis, using quantitative measures of both axonal density and white matter atrophy. The calculated total number of axons was reduced significantly (mean ± SD, 5.4 × 107 ± 3.1 × 107) compared with normal controls (11.6 × 107 ± 2.2 × 107, p = 0.001) with a reduction both in axonal density (median, 34%; range, 16–56%; p = 0.004) and area (mean ± SD: multiple sclerosis, 584 ± 170 mm2; controls, 871 ± 163 mm2; p = 0.004). These results confirm substantial axonal loss in the normal appearing white matter and demonstrate that measures of both axonal density and white matter volume are necessary to appreciate the full extent of axonal loss. Ann Neurol 2000;47:391–395

Guidelines on use of anti-IFN-beta antibody measurements in multiple sclerosis: report of an EFNS Task Force on IFN-beta antibodies in multiple sclerosis.

Therapy‐induced binding and neutralizing antibodies is a major problem in interferon (IFN)‐β treatment of multiple sclerosis. The objective of this study was to provide guidelines outlining the methods and clinical use of the measurements of binding and neutralizing antibodies. Systematic search of the Medline database for available publications on binding and neutralizing antibodies was undertaken. Appropriate publications were reviewed by one or more of the task force members. Grading of evidence and recommendations was based on consensus by all task force members. Measurements of binding antibodies are recommended for IFN‐β antibody screening before performing a neutralizing antibody (NAB) assay (Level A recommendation). Measurement of NABs should be performed in specialized laboratories with a validated cytopathic effect assay or MxA production assay using serial dilution of the test sera. The NAB titre should be calculated using the Kawade formula (Level A recommendation). Tests for the presence of NABs should be performed in all patients at 12 and 24 months of therapy (Level A recommendation). In patients who remain NAB‐negative during this period measurements of NABs can be discontinued (Level B recommendation). In patient with NABs, measurements should be repeated, and therapy with IFN‐β should be discontinued in patients with high titres of NABs sustained at repeated measurements with 3‐ to 6‐month intervals (Level A recommendation).

Dok-7 Mutations Underlie a Neuromuscular Junction Synaptopathy

Congenital myasthenic syndromes (CMSs) are a group of inherited disorders of neuromuscular transmission characterized by fatigable muscle weakness. One major subgroup of patients shows a characteristic “limb girdle” pattern of muscle weakness, in which the muscles have small, simplified neuromuscular junctions but normal acetylcholine receptor and acetylcholinesterase function. We showed that recessive inheritance of mutations in Dok-7, which result in a defective structure of the neuromuscular junction, is a cause of CMS with proximal muscle weakness.

Value of sphincter electromyography in the diagnosis of multiple system atrophy.

It is clinically important, to distinguish between idiopathic Parkinsons disease (IPD) and multiple system atrophy (MSA) not only because of the implications for prognosis but also because urinary incontinence is often an early troublesome feature of MSA and by making the correct neurological diagnosis inappropriate urological surgery may be avoided. Onufs nucleus in the sacral cord is the location of the anterior horn cells innervating the sphincters, and it is among central nervous system sites affected by neuronal cell loss in MSA but not in IPD. A systematic analysis of motor units recorded from the sphincter looking for changes of chronic reinnervation has therefore been used to distinguish between these conditions. Sphincter electromyography (EMG) was carried out in 126 patients with suspected MSA with review of their case notes up to 2 years later. Of those in whom a diagnosis of MSA was made, 82% had had an abnormal sphincter EMG.

Association of the APOE epsilon4 allele with disease activity in multiple sclerosis.

OBJECTIVES Allelic variants of the APOE gene are known to influence the course of many neurological diseases and there is increasing evidence that apolipoprotein E (APOE) is a pivotal component in reinnervation and dendritic remodelling after neuronal injury. Previous studies did not show significant differences in the APOE allele frequencies in multiple sclerosis compared with controls but did not examine for correlation with disease severity. This study explores the relation of APOE genotypes with the disease severity. METHODS Ninety five patients with multiple sclerosis were studied. Age of onset, type, and activity of the disease were recorded prospectively and genotyping was performed according to standard protocols. RESULTS APOE allele frequencies of the group as a whole, the relapsing group, or the primary progressive group were not significantly different from those reported from matched historical controls. The ε4 allele was found to be more common in patients with a more aggressive type of multiple sclerosis (odds ratio=2.95, p=0.03). CONCLUSIONS Although APOE does not seem to be implicated in the early pathogenesis of the disease, patients possessing the ε4 allele might have a reduced capacity for neuronal remodelling after relapses.

Discordant white matter N-acetylasparate and diffusion MRI measures suggest that chronic metabolic dysfunction contributes to axonal pathology in multiple sclerosis.

Diffusion MRI and magnetic resonance spectroscopic measurements of selectively neuronally localised N-acetylaspartate (NAA) both have been used widely to assess white matter integrity and axonal loss. We have tested directly the relationship between changes in diffusion MRI parameters and NAA concentrations in the corpus callosum (CC) in an in vivo study of patients with MS. Fifteen MS patients (median EDSS 2.5, range 1-4) were studied with T(1) anatomical, T(2)-weighted, and diffusion-sensitised MRI and PRESS single-voxel MRS. A recently described method, tract-based spatial statistics (TBSS) [Smith, S.M., Jenkinson, M., Johansen-Berg, H., Rueckert, D., Nichols, T.E., Mackay, C.E. et al., 2006. Tract-based spatial statistics: voxelwise analysis of multi-subject diffusion data. Neuroimage 31, 1487-1505] also was used to perform exploratory voxelwise whole-brain analysis of white matter diffusion fractional anisotropy (FA). We found a strong correlation between callosal size and both mean FA (r=0.68, p<0.005) (related specifically to changes in the radial tensor component) and mean inter-hemispheric motor tract connectivity probability (r=0.74, p<0.001). TBSS confirmed that the diffusion anisotropies of white matter voxels specifically within the callosum were correlated with the callosal size. Individual patient global T(2) lesion volumes were correlated with both the probability of callosal connectivity (r=-0.69, p<0.005) and fractional anisotropy across the callosum (r=-0.76, p<0.001). However, absolute concentrations of NAA from the voxel showed no correlation with callosal cross-sectional area, mean connectivity or fractional anisotropy within the callosal pathway. We conclude that diffusion MRI shows changes consistent with sensitivity to axonal loss, but that relative NAA changes are not necessarily related directly to this. Axonal metabolic function, independent of structural integrity, may be a major determinant of NAA measures in MS.

The Multiple Sclerosis Risk Sharing Scheme Monitoring Study--early results and lessons for the future.

BackgroundRisk sharing schemes represent an innovative and important approach to the problems of rationing and achieving cost-effectiveness in high cost or controversial health interventions. This study aimed to assess the feasibility of risk sharing schemes, looking at long term clinical outcomes, to determine the price at which high cost treatments would be acceptable to the NHS.MethodsThis case study of the first NHS risk sharing scheme, a long term prospective cohort study of beta interferon and glatiramer acetate in multiple sclerosis (MS) patients in 71 specialist MS centres in UK NHS hospitals, recruited adults with relapsing forms of MS, meeting Association of British Neurologists (ABN) criteria for disease modifying therapy. Outcome measures were: success of recruitment and follow up over the first three years, analysis of baseline and initial follow up data and the prospect of estimating the long term cost-effectiveness of these treatments.ResultsCentres consented 5560 patients. Of the 4240 patients who had been in the study for a least one year, annual review data were available for 3730 (88.0%). Of the patients who had been in the study for at least two years and three years, subsequent annual review data were available for 2055 (78.5%) and 265 (71.8%) patients respectively. Baseline characteristics and a small but statistically significant progression of disease were similar to those reported in previous pivotal studies.ConclusionSuccessful recruitment, follow up and early data analysis suggest that risk sharing schemes should be able to deliver their objectives. However, important issues of analysis, and political and commercial conflicts of interest still need to be addressed.

Myelin water imaging reflects clinical variability in multiple sclerosis.

Whilst MRI is routinely used for the assessment and diagnosis of multiple sclerosis, there is poor correspondence between clinical disability in primary progressive multiple sclerosis (PPMS) patients and conventional MRI markers of disease activity (e.g., number of enhancing lesions). As PPMS patients show diffuse and global myelin loss, the aim of this study was to evaluate the efficacy of whole-brain myelin water fraction (MWF) imaging in PPMS. Specifically, we sought to use full-brain analysis techniques to: 1) determine the reproducibility of MWF estimates in PPMS brain; 2) compare MWF values in PPMS brain to healthy controls; and 3) establish the relationship between MWF and clinical disability, regionally and globally throughout the brain. Seventeen PPMS patients and seventeen age-matched controls were imaged using a whole-brain multi-component relaxation imaging technique to measure MWF. Analysis of MWF reduction was performed on three spatial levels: 1) histogram; 2) white matter skeleton; and 3) voxel-wise at the single-subject level. From histogram analysis, PPMS patients had significantly reduced global normal appearing white matter MWF (6%, p=0.04) compared to controls. Focal lesions showed lower MWF values than white matter in controls (61%, p<0.001) and patients (59%, p<0.001). Along the white matter skeleton, MWF was diffusely reduced throughout the PPMS brain, with significant correlations between reduced MWF and increased clinical disability (more severe symptoms), as measured by the Expanded Disability Status Scale, within the corpus callosum and frontal, temporal, parietal and occipital white matter. Correlations with the more specific mental and sensory functional system scores were localized to clinically eloquent locations: reduced MWF was significantly associated with increased mental scores in anterior regions (i.e., frontal lobes and genu of the corpus callosum), and increased sensory scores in more posterior regions closer to the sensory cortex. Individual patient MWF maps were also compared to a normative population atlas, which highlighted areas of statistical difference between the individual patient and the population mean. A significant correlation was found between the volume of significantly reduced MWF and clinical disability (p=0.008, R=0.58). Our results show that clinical disability is reflected in particular regions of cerebral white matter that are consistent between subjects, and illustrates a method to examine tissue alteration throughout the brain of individual patients. These results strongly support the use of MWF imaging to evaluate disease activity in PPMS.

Methotrexate is an alternative to azathioprine in neuromyelitis optica spectrum disorders with aquaporin-4 antibodies.

Background Neuromyelitis optica (NMO) is a severe autoimmune inflammatory disorder associated with considerable relapse-related disability. Immunosuppression is the mainstay of treatment but many patients do not tolerate first-line immunosuppressive agents, or experience ongoing relapses. Objective To evaluate the effectiveness and tolerability of methotrexate in aquaporin-4 antibody seropositive NMO spectrum disorders. Methods Retrospective observational case series of 14 aquaporin-4 antibody positive NMO and NMO spectrum disorder patients treated with methotrexate at two specialist centres within the UK. Annualised relapse rates, Expanded Disability Status Scale scores and tolerability were evaluated. Results Median duration of treatment with methotrexate was 21.5 months (range 6–28 months) and only three patients were prescribed it first line. Median annualised relapse rate significantly decreased following treatment (0.18 during methotrexate therapy vs 1.39 premethotrexate; p<0.005). On treatment, 43% patients were relapse free, although this increased to 64% when relapses occurring within the first 3 months of treatment or on subtherapeutic doses were excluded. Disability stabilised or improved in 79%. No patients stopped methotrexate due to adverse effects. Conclusions Methotrexate is a commonly prescribed drug in general practice and when used in NMO it reduces relapse frequency, stabilises disability and is well tolerated, even in patients who have failed one or more other treatments. We would therefore recommend methotrexate as a treatment option in NMO patients who do not tolerate first-line therapy, experience ongoing relapses or in situations where financial constraints limit the available treatment options.

Axonal damage in the spinal cord of multiple sclerosis patients detected by magnetic resonance spectroscopy

Axonal damage is a major factor contributing to permanent disability in patients with multiple sclerosis (MS); it has been extensively investigated in the brain using magnetic resonance spectroscopy (MRS). In this study, MRS was used to investigate the degree of neuronal damage in the cervical spinal cord in MS. Spectra were acquired from spinal cord and brain in 11 patients with MS (expanded disability status score [EDSS], range 2.5–7.0) and 11 controls. Brain lesion volume and spinal cord cross‐sectional area were measured. Concentration of the neuronal metabolite N‐acetyl‐aspartate ([NAA]) was reduced in the spinal cord in MS patients relative to controls (reduced by 32%, P < 0.05), indicating significant neuronal damage. Additionally, the spinal cord was significantly atrophied in MS patients (15%, P < 0.001). No significant reduction in brain [NAA] was seen in the MS group. There were no correlations between clinical measures and cord atrophy or brain lesion volume on MRI; however, spinal cord [NAA] correlated with the cerebellar subscore of the neurological assessment (P < 0.005), while brain [NAA] correlated with disease duration (P < 0.05). MRS demonstrated cellular damage within the cord over and above the tissue atrophy seen by MRI. Combining MRI and MRS may therefore give a more complete picture of neurodegeneration in the spinal cord. Magn Reson Med 58:880–885, 2007.