Evidence of axonal damage in the early stages of multiple sclerosis and its relevance to disability

Real-life impact of early interferon beta therapy in relapsing multiple sclerosis

OBJECTIVE

Recent findings support greater efficacy of early vs. delayed interferon beta (IFNbeta) treatment in patients with a first clinical event suggestive of multiple sclerosis (MS). We aimed to evaluate the effectiveness of early IFNbeta treatment in definite relapsing-remitting MS (RRMS) and to assess the optimal time to initiate IFNbeta treatment with regard to the greatest benefits on disability progression.

METHODS

A cohort of 2,570 IFNbeta-treated RRMS patients was prospectively followed for up to 7 years in 15 Italian MS Centers. A Cox proportional hazards regression model adjusted for propensity score (PS) quintiles was used to assess differences between groups of patients with early vs. delayed IFNbeta treatment on risk of reaching a 1-point progression in the Expanded Disability Status Scale (EDSS) score, and the EDSS 4.0 and 6.0 milestones. A set of PS-adjusted Cox hazards regression models were calculated according to different times of treatment initiation (within 1 year up to within 5 years from disease onset). A sensitivity analysis was performed to assess the robustness of findings.

RESULTS

The lowest hazard ratios (HRs) for the three PS quintiles-adjusted models were obtained by a cutoff of treatment initiation within 1 year from disease onset. Early treatment significantly reduced the risk of reaching a 1-point progression in EDSS score (HR = 0.63; 95% CI = 0.48-0.85; p < 0.002), and the EDSS 4.0 milestone (HR = 0.56; 95% CI = 0.36-0.90; p = 0.015). Sensitivity analysis showed the bound of significance for unmeasured confounders.

INTERPRETATION

Greater benefits on disability progression may be obtained by an early IFNbeta treatment in RRMS.

Effect of glatiramer acetate on conversion to clinically definite multiple sclerosis in patients with clinically isolated syndrome (PreCISe study): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Glatiramer acetate, approved for the treatment of relapsing-remitting multiple sclerosis, reduces relapses and disease activity and burden monitored by MRI. We assessed the efficacy of early treatment with glatiramer acetate in delaying onset of clinically definite multiple sclerosis.

METHODS

In this randomised, double-blind trial, undertaken in 80 sites in 16 countries, 481 patients presenting with a clinically isolated syndrome with unifocal manifestation, and two or more T2-weighted brain lesions measuring 6 mm or more, were randomly assigned to receive either subcutaneous glatiramer acetate 20 mg per day (n=243) or placebo (n=238) for up to 36 months, unless they converted to clinically definite multiple sclerosis. The randomisation scheme used SAS-based blocks stratified by centre, and patients and all personnel were masked to treatment assignment. The primary endpoint was time to clinically definite multiple sclerosis, based on a second clinical attack. Analysis was by intention to treat. A preplanned interim analysis was done for data accumulated from 81% of the 3-year study exposure. This study was registered with ClinicalTrials.gov, number NCT00666224.

FINDINGS

All randomly assigned participants were analysed for the primary outcome. Glatiramer acetate reduced the risk of developing clinically definite multiple sclerosis by 45% compared with placebo (hazard ratio 0.55, 95% CI 0.40-0.77; p=0.0005). The time for 25% of patients to convert to clinically definite disease was prolonged by 115%, from 336 days for placebo to 722 days for glatiramer acetate. The most common adverse events in the glatiramer acetate group were injection-site reactions (135 [56%] glatiramer acetate vs 56 [24%] placebo) and immediate post-injection reactions (47 [19%] vs 12 [5%]).

INTERPRETATION

Early treatment with glatiramer acetate is efficacious in delaying conversion to clinically definite multiple sclerosis in patients presenting with clinically isolated syndrome and brain lesions detected by MRI.

FUNDING

Teva Pharmaceutical Industries, Israel.

Shifting the paradigm toward earlier treatment of multiple sclerosis with interferon beta

BACKGROUND

Axonal damage occurs early in the course of multiple sclerosis (MS). Among untreated patients, 85% to 94% with a first clinically isolated syndrome (CIS) suggestive of MS and positive findings on magnetic resonance imaging (MRI) are at risk for developing MS.

OBJECTIVES

This article reviews the current literature concerning early diagnosis of MS, the rationale for early immunomodulatory treatment of patients with a CIS and MRI evidence of central nervous system lesions, and the efficacy of early treatment with interferon beta (IFN-beta).

METHODS

MEDLINE was searched from 1990 through the end of 2008 for papers published in English concerning the treatment of MS. Search terms included IFN-beta, early treatment, CIS, and multiple sclerosis, and limits were set to return results related to human clinical trials in adults.

RESULTS

Three pivotal randomized controlled trials were identified, 2 involving IFN-beta-1a (30 microg IM once weekly and 22 microg SC once weekly) and 1 involving IFN-beta-1b (250 microg SC qod). In these trials, treatment with IFN-beta effectively reduced the risk of developing MS by up to 50% in patients with a CIS. Furthermore, compared with delayed treatment, early treatment was associated with a reduced risk of disease progression: a 40% reduction in risk for confirmed disability progression at 3 years and a 41% reduction in risk of MS at 3 years.

CONCLUSIONS

The evidence that axonal damage begins in the early stages of MS, before symptoms are evident, provides a rationale for early intervention with immunomodulatory agents. In 3 pivotal clinical trials, IFN-beta effectively reduced the risk of developing clinically definite MS in CIS patients with a first demyelinating event and positive brain MRI.

Review: Treatment of early multiple sclerosis: the value of treatment initiation after a first clinical episode

Multiple sclerosis is a chronic, demyelinating disorder of the central nervous system. It is characterised by progressive neurological disability, which is likely to occur as a result of permanent axonal damage. Such damage may be reflected by brain atrophy, which can be identified early in the course of the disease. Patients who present with an initial episode of inflammatory demyelination, commonly referred to as a clinically isolated syndrome, are at high risk of developing clinically definite multiple sclerosis, especially if their magnetic resonance imaging studies suggest the presence of multi-focal disease. Treatment with disease-modifying therapies at the initial episode of demyelination may postpone this development. In this review we present an overview of evidence supporting early treatment initiation. We focus on three large placebo-controlled trials of interferon beta therapy: Controlled High-Risk Avonex® Multiple Sclerosis Prevention Study, Early Treatment of Multiple Sclerosis and Betaferon ® in Newly Emerging Multiple Sclerosis for Initial Treatment. Results from these early treatment studies are presented, and the impact of using interferon beta treatment in the early stages of disease is discussed with the aim of considering optimal therapeutic strategies to improve long-term patient outcome.

3-Tesla Study of the Spinal Cord White Matter

Spinal cord as soon as brain, can be affected by dysmyelinating and demyelinating diseases, as Multiple Sclerosis (MS), Acute Disseminated Encephalomyelitis (ADEM), Neuromyelis Optica (NMO) and Transverse Myelitis. Investigation of the spinal cord with a high field strength MR system is hampered by the inhomogeneous magnetic field, physiological movements and the small size of the anatomical area. We describe normal and pathological neuroradiological findings in spinal cord white matter and the parameters of optimized sequences for use with the 3T MR systems.

Dietary patterns in clinical subtypes of multiple sclerosis: an exploratory study

Backround

Multiple sclerosis is a neurodegenerative disorder with a wide range in disease course severity. Many factors seem to be implicated in multiple sclerosis disease course, and diet has been suggested to play a role. Because limited data is present in the literature it was investigated whether variations in dietary intake may be related to the severity of the disease course in multiple sclerosis.

Methods

Using a food diary during 14 days, the dietary intake of 23 nutrients and vitamins was measured in patients with primary progressive (n = 21), secondary progressive (n = 32), and benign multiple sclerosis (n = 27) and compared to each other. The intake measured was also compared to the intake of the Dutch population and to the recommended daily allowance.

Results

Compared to the other MS groups, the secondary progressive MS patients had a lower intake of magnesium, calcium and iron. The total group of MS patients had, compared to the Dutch population, a lower intake of folate, magnesium and copper and a lower energy intake. Compared to the daily recommended allowance, the MS patients had a lower than recommended intake of folic acid, magnesium, zinc and selenium.

Conclusion

Magnesium, calcium and iron intake may possibly be related to MS disease progression, and should receive further attention. This is important because no effective neuroprotective treatment for MS patients is available.

[Magnetic resonance imaging of central nervous system inflammation]

Magnetic resonance imaging (MRI) is widely used to explore central nervous system inflammatory disorders, especially multiple sclerosis (MS). Advanced MRI methods are bringing more sensitive and specific tools for each step of the inflammatory process. In this review, we discuss the different MRI approaches for inflammatory disorders exploration, especially MS. We give particular emphasize on sensibility and specificity of each MRI approach and we also discuss the current knowledge concerning biological and histopathological substratum that could explain MRI signal with each modality.

Aerobic fitness is associated with gray matter volume and white matter integrity in multiple sclerosis

Alterations in gray and white matter have been well documented in individuals with multiple sclerosis. Severity and extent of such brain tissue damage have been associated with cognitive impairment, disease duration and neurological disability, making quantitative indices of tissue damage important markers of disease progression. In this study, we investigated the association between cardiorespiratory fitness and measures of gray matter atrophy and white matter integrity. Employing voxel-based approaches to analysis of gray matter and white matter, we specifically examined whether higher levels of fitness in multiple sclerosis participants were associated with preserved gray matter volume and integrity of white matter. We found a positive association between cardiorespiratory fitness and regional gray matter volumes and higher focal fractional anisotropy values. Statistical mapping revealed that higher levels of fitness were associated with greater gray matter volume in the midline cortical structures including the medial frontal gyrus, anterior cingulate cortex and the precuneus. Further, we also found that increasing levels of fitness were associated with higher fractional anisotropy in the left thalamic radiation and right anterior corona radiata. Both preserved gray matter volume and white matter tract integrity were associated with better performance on measures of processing speed. Taken together, these results suggest that fitness exerts a prophylactic influence on the structural decline observed early on, preserving neuronal integrity in multiple sclerosis, thereby reducing long-term disability.

In-vivo evidence for stable neuroaxonal damage in the brain of patients with benign multiple sclerosis

OBJECTIVE

The term benign multiple sclerosis (BMS) is referred to patients who have a mild or absent disability several years after disease clinical onset. Axonal damage can be measured in vivo using proton MR spectroscopy ((1)H-MRS). In this study, we quantified the severity of "global" axonal damage in BMS and early relapsing-remitting (RR) MS patients, using whole brain N-acetylaspartate (WBNAA) (1)H-MRS, to better elucidate the structural correlates of a non-disabling disease evolution.

METHODS

WBNAA concentration was measured in 37 patients with BMS (mean disease duration 22.3 years) and 17 patients with early RRMS (mean disease duration 4.0 years), using an unlocalized (1)H-MRS sequence. Dual echo and T1-weighted scans were also obtained to measure T2-hyperintense lesion volume (TLV) and normalized brain volume (NBV).

RESULTS

TLV was higher in BMS (mean TLV = 13.1 mL) than in early RRMS patients (mean TLV = 7.2 mL) (P = 0.018), whereas neither NBV (mean NBV: 1491.0 mL in BMS vs 1520.3 mL in RRMS) nor WBNAA concentration (mean WBNAA: 10.5 mmol in BMS vs 11.4 mmol in RRMS) significantly differed between the two groups. In MS patients, no correlation was found between WBNAA concentration and Expanded Disability Status Scale (EDSS), TLV and NBV.

CONCLUSIONS

The similar WBNAA concentrations seen in BMS and early RRMS patients fit with the notion that a non-disabling long-term evolution of MS may be due, at least in part, to non-progression of pathology. Such a condition seems to be independent from MRI-visible lesions burden.

High-dose, high-frequency recombinant interferon beta-1a in the treatment of multiple sclerosis

BACKGROUND

There is at present no cure for multiple sclerosis (MS), and existing therapies are designed primarily to prevent lesion formation, decrease the rate and severity of relapses and delay the resulting disability by reducing levels of inflammation.

OBJECTIVE

The aim of this review was to assess the treatment of relapsing MS with particular focus on subcutaneous (s.c.) interferon (IFN) beta-1a.

METHOD

The literature on IFN beta-1a therapy of MS was reviewed based on a PubMed search (English-language publications from 1990) including its pharmacodynamics and pharmacokinetics, clinical efficacy in relapsing MS as shown in placebo-controlled studies and in comparative trials, efficacy in secondary progressive MS, safety and tolerability, and the impact of neutralizing antibodies.

CONCLUSION

The literature suggests that high-dose, high-frequency s.c. IFN beta-1a offers an effective option for treating patients with relapsing MS, with proven long-term safety and tolerability, and has a favourable benefit-to-risk ratio compared with other forms of IFN beta.

Axial diffusivity is the primary correlate of axonal injury in the experimental autoimmune encephalomyelitis spinal cord: a quantitative pixelwise analysis

The dissociation between magnetic resonance imaging (MRI) and permanent disability in multiple sclerosis (MS), termed the clinicoradiological paradox, can primarily be attributed to the lack of specificity of conventional, relaxivity-based MRI measurements in detecting axonal damage, the primary pathological correlate of long-term impairment in MS. Diffusion tensor imaging (DTI) has shown promise in specifically detecting axonal damage and demyelination in MS and its animal model, experimental autoimmune encephalomyelitis (EAE). To quantify the specificity of DTI in detecting axonal injury, in vivo DTI maps from the spinal cords of mice with EAE and quantitative histological maps were both registered to a common space. A pixelwise correlation analysis between DTI parameters, histological metrics, and EAE scores revealed a significant correlation between the water diffusion parallel to the white matter fibers, or axial diffusivity, and EAE score. Furthermore, axial diffusivity was the primary correlate of quantitative staining for neurofilaments (SMI31), markers of axonal integrity. Both axial diffusivity and neurofilament staining were decreased throughout the entire white matter, not solely within the demyelinated lesions seen in EAE. In contrast, although anisotropy was significantly correlated with EAE score, it was not correlated with axonal damage. The results demonstrate a strong, quantitative relationship between axial diffusivity and axonal damage and show that anisotropy is not specific for axonal damage after inflammatory demyelination.

Differential sensitivity of oligodendrocytes and motor neurons to reactive nitrogen species: implications for multiple sclerosis

Depending on its concentration, nitric oxide (NO) has beneficial or toxic effects. In pathological conditions, NO reacts with superoxide to form peroxynitrite, which nitrates proteins forming nitrotyrosine residues (3NY), leading to loss of protein function, perturbation of signal transduction, and cell death. 3NY immunoreactivity is present in many CNS diseases, particularly multiple sclerosis. Here, using the high flux NO donor, spermine-NONOate, we report that oligodendrocytes are resistant to NO, while motor neurons are NO sensitive. Motor neuron sensitivity correlates with the NO-dependent formation of 3NY, which is significantly more pronounced in motor neurons when compared with oligodendrocytes, suggesting peroxynitrite as the toxic molecule. The heme-metabolizing enzyme, heme-oxygenase-1 (HO1), is necessary for oligodendrocyte NO resistance, as demonstrated by loss of resistance after HO1 inhibition. Resistance is reinstated by peroxynitrite scavenging with uric acid further implicating peroxynitrite as responsible for NO sensitivity. Most importantly, differential sensitivity to NO is also present in cultures of primary oligodendrocytes and motor neurons. Finally, motor neurons cocultured with oligodendrocytes, or oligodendrocyte-conditioned media, become resistant to NO toxicity. Preliminary studies suggest oligodendrocytes release a soluble factor that protects motor neurons. Our findings challenge the current paradigm that oligodendrocytes are the exclusive target of multiple sclerosis pathology.

Brain imaging of multiple sclerosis: the next 10 years

MR imaging has had a major impact on understanding the dynamic neuropathologic findings of multiple sclerosis (MS), early diagnosis of the disease, and clinical trial conduct. The next 10 years can be expected to see further advances with a greater emphasis on large multicenter studies, new techniques and hardware allowing greater imaging sensitivity and resolution, and the exploitation of positron emission tomography molecular imaging for MS. The impact should be felt with a new emphasis on gray matter disease and processes of repair. With new ways of monitoring the disease, new treatment targets should become practical, helping to translate advances in the understanding of immunology and regenerative medicine into novel therapies.

The role of axonopathy in the mechanisms of development of demyelination processes in the central and peripheral nervous system

The role of axonopathy in the development of demyelinating processes in the CNS and peripheral nervous system was addressed in studies of 43 patients with multiple sclerosis (MS) and 144 patients with chronic inflammatory demyelinating polyneuropathy (CIDPN). Patients with MS were found to have foci of reduced MRI intensity in the T1 regime ("black holes," present in 28%) and regional atrophy of the cerebral cortex (in 46%), which showed a significant association with the degree of invalidity on the EDSS (Kendall tau = 0.38 and 0.43; p = 0.038 and 0.021, respectively). The mean fatigue score on the FSS was 4.9 (3.6; 5.4). A significant increase in the central conduction time on the background of fatigue (p = 0.016), along with an absence of signs of impaired reliability of neuromuscular transmission and an absence of past-activation phenomena, suggested that central mechanisms were predominant in the formation of fatigue phenomena in MS. In addition, 34.9% of patients with MS showed signs of peripheral nervous system involvement, while the clinical-electrophysiological pattern in 12.5% of patients with CIDPN showed signs of CNS involvement. These data widen existing concepts of the mechanisms of formation of axonopathy in the CNS, based on evidence for the development of axon-demyelinating processes in CIDPN, which is the most accessible model of demyelination for study using contemporary neurophysiological methods.

Impaired regulation of electron transport chain subunit genes by nuclear respiratory factor 2 in multiple sclerosis

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease. Recently, decreased expression of nuclear encoded electron transport chain genes was found in neurons in MS cortex. To understand the transcriptional mechanisms responsible for the coordinate down regulation of these genes, we performed electrophoretic mobility shifts with nuclear extracts isolated from gray matter from nonlesion areas of postmortem MS and control cortex. Nine tissue blocks from eight different MS brains and six matched control blocks from five control brains were analyzed. We identified a decrease in a transcription factor complex containing nuclear respiratory factor 2 (NRF-2) in nuclear extracts isolated from MS cortex. This decrease is correlated with decreased expression of electron transport chain subunit genes and increased oxidative damage measured by increased anti-nitrotyrosine immunoreactivity. We conclude that in MS cortex a chronic increase in oxidative stress leads to aberrant regulation of transcription of genes involved in energy metabolism.

Effect of noscapine and vincristine combination on demyelination and cell proliferation in vitro

Peripheral neuropathy is a common, dose-limiting side effect of vincristine, a frontline therapy for acute lymphoblastic leukemia. Combination chemotherapy that reduces the neurotoxicity without compromising the efficacy of vincristine would improve patient outcomes. We performed in vitro studies using a combination of microtubule-binding antimitotics, noscapine and vincristine. In cell cultures containing neurons, astrocytes, and oligodendrocytes, vincristine caused demyelination as shown by transmission electron microscopy. A combination of vincristine and noscapine protected against demyelination. Human acute lymphoblastic and acute myelogenous leukemia cell lines CCRF-CEM and HL-60, respectively, were used to determine the antiproliferative effect of this novel drug combination. Vincristine and noscapine decreased cell proliferation with IC(50) concentrations of 1 nM and 20 microM, respectively. Analysis of dose-effect relationships using isobolograms and combination indices demonstrated that noscapine acts synergistically with vincristine. Thus, noscapine is a promising candidate for use with vincristine to decrease neurotoxicity and enhance antineoplastic effectiveness.

New imaging techniques in the diagnosis of multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a chronic disabling disorder histopathologically characterized by inflammation, demyelination and axonal loss. Conventional MRI has made most contributions to the diagnosis of MS. However, it is not sufficiently sensitive and specific to reveal the extent and severity of the damage in the disease. Other nuclear magnetic resonance (NMR) techniques including magnetic resonance spectroscopy, magnetization transfer imaging, diffusion weighted and diffusion tensor imaging, and functional MRI have provided additional information that improves the diagnosis and understanding of MS. Optical techniques including optical coherence tomography (OCT) and coherent anti-Stokes Raman scattering (CARS) microscopy have shown promise in diagnosis and mechanistic study of myelin diseases.

OBJECTIVE

To review new imaging techniques and their potential in diagnosis of MS.

METHOD

The principles of three imaging techniques (MRI, OCT and CARS) and their applications to MS studies are described. Their advantages and disadvantages are compared.

CONCLUSION

Conventional MRI remains a critical tool in the diagnosis of MS. Alternative NMR/MRI techniques have improved specificity for the detection of lesions and provided more quantitative information about MS. Optical techniques including OCT and CARS microscopy are opening up new ways for diagnosis and mechanistic study of myelin diseases.

Canadian treatment optimization recommendations (TOR) as a predictor of disease breakthrough in patients with multiple sclerosis treated with interferon β-1a: analysis of the PRISMS study

Background

Early intervention with an effective disease-modifying drug (DMD) offers the best chance of limiting the inflammatory process that contributes to irreversible axonal damage correlating with disability in multiple sclerosis (MS). It is equally important to ascertain fairly quickly whether patients are responding positively to the choice of therapy to allow time for either a treatment modification or a switch in treatment, a process we termed “treatment optimization”. Various treatment optimization recommendations (TOR) have been proposed to help decide when a patient taking an MS DMD might be showing a sub-optimal response. We have applied the clinical scheme proposed by the Canadian TOR to the patients involved in the Prevention of Relapses and disability by Interferon Subcutaneously in MS 4-year (PRISMS-4) study, who received interferon β-1a treatment for 4 years, with the TOR applied retrospectively at year 1.

Objective

The aim of this investigation was to examine whether these TOR were able to predict which patients would go on to develop disease breakthrough (defined as any relapses or disease progression), indicative of a sub-optimal response over the ensuing 3 years of study and therefore might have benefited from a change in treatment.

Results

We found 39% of patients receiving therapy experienced either a medium or high level of concern of breakthrough after a year of treatment, and 89% of these patients went on to develop further breakthrough over years 2–4. Although 67% of the 61% of patients having no or low-level concern after a year of treatment also experienced further disease breakthrough, it was significantly less than the medium or high group.

Conclusion

This study shows that the Canadian TOR may be an important tool for early treatment optimization.

Protecting axons in multiple sclerosis

Typically patients with multiple sclerosis (MS) experience acute episodes of neurological dysfunction, which recover followed, at a later stage, by slow and insidious accumulation of disability (disease progression). Disease progression reflects axon damage and loss within the central nervous system. However, the precise mechanism of axon injury in MS is not clear. Inflammation occurring during acute relapses undoubtedly causes some degree of acute axon damage, but epidemiological data and treatment studies have suggested that inflammation alone is not the sole cause of axonopathy. Indeed, there appears to be dissociation between inflammation and disease progression once a certain level of clinical disability has been reached because immune suppression in patients who have established disease progression does not halt the slow decrease of function. The slow and insidious loss of neurological function that occurs during the progressive phase of the disease implies a degenerative process. Whether axon drop-out occurs at these later stages because of previous inflammatory damage to axons; because of low grade inflammation causing damage to already vulnerable demyelinated axons; because of loss of trophic environment for axons to survive; or as part of a completely independent neurodegenerative process is not clear. Understanding disease mechanisms involved in the axonopathy of MS allows for the development of rational therapies for disease progression.

Axonal injury detected by in vivo diffusion tensor imaging correlates with neurological disability in a mouse model of multiple sclerosis

Recent studies have suggested that axonal damage, and not demyelination, is the primary cause of long-term neurological impairment in multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). The axial and radial diffusivities derived from diffusion tensor imaging have shown promise as non-invasive surrogate markers of axonal damage and demyelination, respectively. In this study, in vivo diffusion tensor imaging of the spinal cords from mice with chronic EAE was performed to determine if axial diffusivity correlated with neurological disability in EAE assessed by the commonly used clinical scoring system. Axial diffusivity in the ventrolateral white matter showed a significant negative correlation with EAE clinical score and was significantly lower in mice with severe EAE than in mice with moderate EAE. Furthermore, the greater decreases in axial diffusivity were associated with greater amounts of axonal damage, as confirmed by quantitative staining for non-phosphorylated neurofilaments (SMI32). Radial diffusivity and relative anisotropy could not distinguish between the groups of mice with moderate EAE and those with severe EAE. The results further the notion that axial diffusivity is a non-invasive marker of axonal damage in white matter and could provide the necessary link between pathology and neurological disability.

MRI identification of the rostral-caudal pattern of pathology within the corpus callosum in the cuprizone mouse model

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](parallel) and ADC(perpendicular)). 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(parallel), and elevated ADC(perpendicular) 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.

Magnetic resonance imaging metrics and their correlation with clinical outcomes in multiple sclerosis: a review of the literature and future perspectives

Magnetic resonance imaging (MRI) has revolutionized the diagnosis and management of patients with multiple sclerosis (MS). Conventional MRI metrics are employed as primary endpoints in proof-of-concept clinical trials evaluating new drugs for MS and as secondary endpoints in definitive phase III trials. Metrics derived from non-conventional MRI techniques are now emerging and hold significant promise since they appear to be more correlated with the most disabling features of MS. However, none of these has been approved for use as a surrogate endpoint for accumulation of physical disability, which is the most important clinical endpoint of this disease. Taking into account the large numbers of patients needed, the extensive exposure to placebo, and the relatively long duration required for phase III clinical trials to show a meaningful effect on progression of disability, the need for a valid, reliable, and objective paraclinical marker of disease evolution cannot be overemphasized. This paper reviews the most up-to-date data regarding MRI techniques, their relationship with central nervous system pathology, as well as with clinical endpoints, and proposes future insights into the use of MRI metrics as surrogate endpoints in clinical trials of MS.

Metabolic alterations in medication-free patients with bipolar disorder: a 3T CSF-corrected magnetic resonance spectroscopic imaging study

The objective of this study was to determine whether cerebrospinal fluid(CSF)-corrected concentrations of N-acetylaspartate are lower in several brain regions of drug- and medication-free subjects with bipolar disorder as compared with matched healthy controls. Bipolar subjects (n=21) and age- and sex-matched healthy control (n=21) were studied using proton magnetic resonance spectroscopic imaging on a 3T magnetic resonance (MR) scanner. Spectra were quantified using the LCModel, and metabolite values were CSF-corrected to yield metabolite concentrations. Fourteen regions of interest and five metabolite concentrations in each subject were selected for statistical analysis. We found that bipolar subjects had significantly decreased N-acetylaspartate concentrations in both caudate heads and the left lentiform nucleus. Choline and creatine in the head of the right caudate were also significantly decreased in bipolar subjects. Significantly increased myo-inositol was found in the left caudate head in bipolar subjects. Bipolar subjects showed significantly decreased glutamate/glutamine concentrations in the frontal white matter bilaterally and in the right lentiform nucleus. No differences were found for other metabolites examined. These preliminary findings suggest decreased neuronal density or viability in the basal ganglia and neurometabolic abnormalities in the frontal lobes of subjects with bipolar disorder.

Imaging of remyelination and neuronal health

Remyelination of axons that have been demyelinated due to multiple sclerosis (MS) may be a critical step in restoring the damaged axons and reversing the disease process. While it is possible to establish the presence of remyelination with microscopy of tissue samples, it is important to have noninvasive or minimally invasive methods to measure remyelination in living animals and humans. Such tools are critical to establishing the efficacy of agents purported to promote or enhance remyelination. This chapter reviews the technology of imaging of the brain, its application to MS, and the current state of imaging techniques for measuring remyelination and the health of the associated neurons in the setting of MS.

Polyunsaturated fatty acids in the pathogenesis and treatment of multiple sclerosis

Epidemiological, biochemical, animal model and clinical trial data described in this overview strongly suggest that polyunsaturated fatty acids, particularly n-6 fatty acids, have a role in the pathogenesis and treatment of multiple sclerosis (MS). Data presented provides further evidence for a disturbance in n-6 fatty acid metabolism in MS. Disturbance of n-6 fatty acid metabolism and dysregulation of cytokines are shown to be linked and a "proof of concept clinical trial" further supports such a hypothesis. In a randomised double-blind, placebo controlled trial of a high dose and low dose selected GLA (18:3n-6)-rich oil and placebo control, the high dose had a marked clinical effect in relapsing-remitting MS, significantly decreasing the relapse rate and the progression of disease. Laboratory findings paralleled clinical changes in the placebo group in that production of mononuclear cell pro-inflammatory cytokines (TNF-alpha, IL-1beta) was increased and anti-inflammatory TGF-beta markedly decreased with loss of membrane n-6 fatty acids linoleic (18:2n-6) and arachidonic acids (20:4n-6). In contrast there were no such changes in the high dose group. The improvement in disability (Expanded Disability Status Scale) in the high dose suggests there maybe a beneficial effect on neuronal lipids and neural function in MS. Thus disturbed n-6 fatty acid metabolism in MS gives rise to loss of membrane long chain n-6 fatty acids and loss of the anti-inflammatory regulatory cytokine TGF-beta, particularly during the relapse phase, as well as loss of these important neural fatty acids for CNS structure and function and consequent long term neurological deficit in MS.

Mechanisms of neuronal damage in multiple sclerosis and its animal models: role of calcium pumps and exchangers

Multiple sclerosis is an inflammatory, demyelinating and neurodegenerative disorder of the central nervous system. Increasing evidence indicates that neuronal pathology and axonal injury are early hallmarks of multiple sclerosis and are major contributors to progressive and permanent disability. Yet, the mechanisms underlying neuronal dysfunction and damage are not well defined. Elucidation of such mechanisms is of critical importance for the development of therapeutic strategies that will prevent neurodegeneration and confer neuroprotection. PMCA2 (plasma-membrane Ca(2+)-ATPase 2) and the NCX (Na(+)/Ca(2+) exchanger) have been implicated in impairment of axonal and neuronal function in multiple sclerosis and its animal models. As PMCA2 and NCX play critical roles in calcium extrusion in cells, alterations in their expression or activity may affect calcium homoeostasis and thereby induce intracellular injury mechanisms. Interventions that restore normal PMCA2 and NCX activity may prevent or slow disease progression by averting neurodegeneration.

Pattern of axonal injury in murine myelin oligodendrocyte glycoprotein induced experimental autoimmune encephalomyelitis: implications for multiple sclerosis

Axonal damage is a correlate for increasing disability in multiple sclerosis. Animal models such as experimental autoimmune encephalomyelitis (EAE) may help to develop better therapeutical neuroprotective strategies for the human disease. Here we investigate the pattern of axonal injury in murine myelin oligodendrocyte glycoprotein peptide 35-55 (MOG) induced EAE. Inflammatory infiltration, axonal densities and expression of amyloid precursor protein (APP), neurofilaments (SMI31 and 32) as well as expression of sodium channels were quantified in lesions, the perilesional area and normal appearing white matter (NAWM). Quantification of T cells and macrophages revealed a significant reduction of inflammatory infiltration at later disease stages despite an increase of demyelinated areas and persistent clinical disability. In lesions, axonal density was already significantly reduced early and throughout all investigated disease stages. A significant axonal loss was also seen in the grey matter and at later time points in the perilesion as well as NAWM. Numbers of axons characterized by non-phosphorylated neurofilaments and re-distribution of sodium channels 1.2 and 1.6 increased over the course of MOG-EAE whilst APP positive axons peaked at the maximum of disease. Finally, double-labeling experiments revealed a strong colocalization of sodium channels with APP, neurofilaments and the axonal nodal protein Caspr, but not glial and myelin markers in actively demyelinating lesions. In summary, progressive axonal loss distant from lesions is mainly associated with changes in neurofilament phosphorylation, re-distribution of sodium channels and demyelination. This axonal loss is dissociated from acute inflammatory infiltration and markedly correlates with clinical impairment. Consequently, therapeutic intervention may be promising at early stages of EAE focusing on inflammation, or later in disease targeting degenerative mechanisms.

Immunological aspects of axon injury in multiple sclerosis

The role of immune-mediated axonal injury in the induction of nonremitting functional deficits associated with multiple sclerosis is an area of active research that promises to substantially alter our understanding of the pathogenesis of this disease and modify or change our therapeutic focus. This review summarizes the current state of research regarding changes in axonal function during demyelination, provides evidence of axonal dysmorphia and degeneration associated with demyelination, and identifies the cellular and molecular effectors of immune-mediated axonal injury. Finally, a unifying hypothesis that links neuronal stress associated with demyelination-induced axonal dysfunction to immune recognition and immunopathology is provided in an effort to shape future experimentation.

High field MR imaging and 1H-MR spectroscopy in clinically isolated syndromes suggestive of multiple sclerosis: correlation between metabolic alterations and diagnostic MR imaging criteria

PURPOSE

To prospectively investigate metabolic changes in the normal-appearing white matter (NAWM) of patients presenting with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS) and to correlate these changes to conventional MR imaging findings in terms of MR imaging criteria.

MATERIALS AND METHODS

Multisequence MR imaging of the brain and (1)H-MR spectroscopy of the parietal NAWM were performed in 31 patients presenting with CIS and in 20 controls using a 3. 0 T MR system. MR imaging criteria and International Panel criteria were assessed based on imaging, clinical and paraclinical results. Metabolite ratios and absolute concentrations of N-acetyl-aspartate (tNAA), myoinositol (Ins), choline (Cho), and total creatine (tCr) were determined. The metabolite concentrations were correlated with the fulfilled MR imaging criteria.

RESULTS

In comparison to the control group, the CIS group showed significantly decreased mean tNAA concentrations (-8. 1%, p = 0. 012). Significant changes could not be detected regarding Ins, tCr and Cho. No significant correlations between absolute metabolite concentrations and MR imaging criteria were observed. Patients with and without a lesion dissemination in space showed no significant differences of their metabolite concentrations.

CONCLUSION

As assessed by (1)H-MRS a significant axonal damage already occurs during the first demyelinating episode in patients with CIS. Conventional MR imaging in terms of diagnostic imaging criteria does not significantly reflect NAWM disease activity in terms of metabolic alterations detected by (1)H-MR spectroscopy.

Astrocytes--friends or foes in multiple sclerosis?

In multiple sclerosis (MS), the presence of demyelinating plaques has concentrated researchers' minds on the role of the oligodendrocyte in its pathophysiology. Recently, with the rediscovery of early and widespread loss of axons in the disease, new emphasis has been put on the role of axons and axon-oligodendrocyte interactions in MS. Despite the fact that, in 1904, Müller claimed that MS was a disease of astrocytes, more recently, astrocytes have taken a back seat, except as the cells that form the final glial scar after all hope of demyelination is over. However, perhaps it is time for the return of the astrocyte to popularity in the pathogenesis of MS, with recent reports on the dual role of astrocytes in aiding degeneration and demyelination, by promoting inflammation, damage of oligodendrocytes and axons, and glial scarring, but also in creating a permissive environment for remyelination by their action on oligodendrocyte precursor migration, oligodendrocyte proliferation, and differentiation. We review these findings to try to provide a cogent view of astrocytes in the pathology of MS.

Clinically benign multiple sclerosis despite large T2 lesion load: can we explain this paradox?

Magnetic resonance imaging (MRI) techniques such as magnetization transfer imaging and magnetic resonance spectroscopy (MRS) may reveal otherwise undetectable tissue damage in multiple sclerosis (MS) and can serve to explain more severe disability than expected from conventional MRI. That an inverse situation may exist where non-conventional quantitative MRI and MRS metrics would indicate less abnormality than expected from T2 lesion load to explain preserved clinical functioning was hypothesized. Quantitative MRI and MRS were obtained in 13 consecutive patients with clinically benign MS (BMS; mean age 44 +/- 9 years) despite large T 2 lesion load and in 15 patients with secondary progressive MS (SPMS; mean age 47 +/- 6 years) matched for disease duration. The magnetization transfer ratio (MTR), magnetization transfer rate (kfor), brain parenchymal fraction (BPF) and brain metabolite concentrations from proton MRS were determined. BMS patients were significantly less disabled than their SPMS counterparts (mean expanded disability status score: 2.1 +/- 1.1 versus 6.2 +/- 1.1; P < 0.001) and had an even somewhat higher mean T2 lesion load (41.2 +/- 27.1 versus 27.9 +/- 24.8 cm3; P = 0.19). Normal appearing brain tissue histogram metrics for MTR and kfor, mean MTR and kfor of MS lesions and mean BPF were similar in BMS and SPMS patients. Levels of N-acetyl-aspartate, choline and myoinositol were comparable between groups. This study thus failed to explain the preservation of function in our BMS patients with large T2 lesion load by a higher morphologic or metabolic integrity of the brain parenchyma. Functional compensation must come from other mechanisms such as brain plasticity.

Prognostic value of high-field proton magnetic resonance spectroscopy in patients presenting with clinically isolated syndromes suggestive of multiple sclerosis

INTRODUCTION

The aim of this study was to determine the prognostic value of metabolic alterations in the normal-appearing white matter (NAWM) of patients presenting with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS) with special regard to the prediction of conversion to definite MS.

METHODS

Using a 3T whole-body MR system, a multisequence conventional MRI protocol and single-voxel proton MR spectroscopy (PRESS, repetition time 2000 ms, echo times 38 ms and 140 ms) of the parietal NAWM were performed in 25 patients presenting with CIS at baseline and in 20 controls. Absolute concentrations of N-acetyl-aspartate (tNAA), myo-inositol (Ins), choline (Cho) and creatine (tCr) as well as metabolite ratios were determined. Follow-up including neurological assessment and conventional MRI was performed 3-4 and 6-7 months after the initial event.

RESULTS

Nine patients converted to definite MS during the follow-up period. Compared to controls, those patients who converted to MS also showed significantly lower tNAA concentrations in the NAWM (-13.4%, P = 0.002) whereas nonconverters (-6.5%, P = 0.052) did not. The Ins concentration was 20.2% higher in the converter group and 1.9% higher in the nonconverter group, but these differences did not reach significance. No significant differences could be observed for tCr and Cho in either patient group.

CONCLUSION

Axonal damage at baseline in patients presenting with CIS was more prominent in those who subsequently converted to definite MS in the short term follow-up, indicating that tNAA might be a sufficient prognostic marker for patients with a higher risk of conversion to early definite MS.

Proteomic strategies in multiple sclerosis and its animal models

The early and precise diagnosis, the prognosis, and the clinical management of multiple sclerosis, remain a considerable challenge. In recent years, the development of novel and powerful proteomic techniques prompted the use of these approaches for the search of unique biomarkers in the cerebrospinal fluid of multiple sclerosis patients. A few studies have also utilized proteomics to delineate the profile of differentially expressed proteins in animal models of the human disease in order to gain global insights into affected pathways. The identification of differentially expressed proteins may be an initial step in the discovery of novel targets and mechanisms that play critical roles in the pathology of multiple sclerosis. Based on these findings, future investigations may elucidate the events leading to demyelination, axonal damage, and neurodegeneration, providing better insights into mechanisms governing the onset and progression of the disease. Although these proteomic studies provide valuable information, they are also faced with a number of challenges. The present review discusses some of the strengths and limitations of proteomic investigations as applied to multiple sclerosis.

Axonal damage but no increased glial cell activity in the normal-appearing white matter of patients with clinically isolated syndromes suggestive of multiple sclerosis using high-field magnetic resonance spectroscopy

BACKGROUND AND PURPOSE

Proton MR spectroscopy ((1)H-MR spectroscopy) is a well-established method for the in vivo investigation of the normal-appearing white matter (NAWM) in patients with multiple sclerosis (MS). Metabolic changes in NAWM are of special interest in patients with clinically isolated syndromes (CIS) suggestive of MS regarding further prognostic classifications. The purpose of this study was to investigate metabolic alterations in NAWM in patients with CIS with use of high-field (1)H-MR spectroscopy and to compare the results to those in patients with an early course of MS.

MATERIALS AND METHODS

With use of a 3T whole-body MR imaging system, single-voxel (1)H-MR spectroscopy (PRESS; TR: 2000 ms; TE: 38 ms and 140 ms) of the parietal NAWM was performed in 20 control subjects, 36 patients with CIS, and 12 patients with MS. Metabolite ratios and concentrations of N-acetylaspartate (tNAA), myo-inositol (mIns), choline, and total creatine (tCr) were determined.

RESULTS

Compared with the control group, mean NAWM mIns concentrations were significantly elevated in the MS group (4.56 mmol/L versus 3.75 mmol/L, P = .02) but not in the CIS group (4.04 mmol/L, P = .44). The higher concentration of mIns in the MS group was also reflected in the increased Ins/tCr ratio (P = .02). The mean NAWM tNAA was significantly decreased in both patient groups compared with the control group (CIS, 13.42 mmol/L, P = .02; MS, 12.77 mmol/L versus 14.51 mmol/L, P = .008).

CONCLUSIONS

A significant increase of the activity of the glial cells can only be observed in patients with an established diagnosis of MS but not in patients with CIS. Axonal damage occurs already during the first demyelinating episode in patients with CIS as well as in patients with definite MS.

MRI in multiple sclerosis: what's inside the toolbox?

Magnetic resonance imaging (MRI) has played a central role in the diagnosis and management of multiple sclerosis (MS). In addition, MRI metrics have become key supportive outcome measures to explore drug efficacy in clinical trials. Conventional MRI measures have contributed to the understanding of MS pathophysiology at the macroscopic level yet have failed to provide a complete picture of underlying MS pathology. They also show relatively weak relationships to clinical status such as predictive strength for clinical progression. Advanced quantitative MRI measures such as magnetization transfer, spectroscopy, diffusion imaging, and relaxometry techniques are somewhat more specific and sensitive for underlying pathology. These measures are particularly useful in revealing diffuse damage in cerebral white and gray matter and therefore may help resolve the dissociation between clinical and conventional MRI findings. In this article, we provide an overview of the array of tools available with brain and spinal cord MRI technology as it is applied to MS. We review the most recent data regarding the role of conventional and advanced MRI techniques in the assessment of MS. We focus on the most relevant pathologic and clinical correlation studies relevant to these measures.

Prolonged response times characterize cognitive performance in multiple sclerosis

Cognitive impairment is amongst the main symptoms affecting multiple sclerosis (MS) and should be comprehensively and accurately assessed. To study the added value of a computerized neuropsychological battery enabling the measurement of response times in the cognitive domains, 58 randomly selected MS patients and 71 age-, gender- and education-matched healthy subjects were evaluated. Construct and discriminant validity were assessed for the standard Neuropsychological Screening Battery for Multiple Sclerosis (NSBMS) and the Mindstreams Computerized Cognitive Battery (MCCB). The MCCB demonstrated good construct validity in comparison with the NSBMS in memory (P < 0.001), executive function (P < 0.001), attention (P < 0.05) and information processing (P < 0.05) domains. In addition, it showed high discriminant validity most prominently for executive function, attention and motor skills (P < 0.001). Response times measured by the computerized battery were longer in all cognitive domains and varied with cognitive load, demonstrating that response time deficits in MS are associated with particular task demands. We conclude that in MS prolonged response times on a range of cognitive tasks signify abnormal conduction within demyelinative tracts.

Correlation between fatigue and brain atrophy and lesion load in multiple sclerosis patients independent of disability

BACKGROUND

Fatigue is a major problem in multiple sclerosis (MS), and its association with MRI features is debated.

OBJECTIVE

To study the correlation between fatigue and lesion load, white matter (WM), and grey matter (GM), in MS patients independent of disability.

METHODS

We studied 222 relapsing remitting MS patients with low disability (scores <or=2 at the Kurtzke Expanded Disability Status Scale). Lesion load, WM and GM were measured by fully automated, operator-independent, multi-parametric segmentation method. T1 and T2 lesion volume were also measured by a semi-automated method. Fatigue was assessed by the Fatigue Severity Scale (FSS), and patients divided in high-fatigue (FSS>or=5; n=197) and low-fatigue groups (FSS<or=4; n=25).

RESULTS

High-fatigue patients showed significantly higher abnormal white matter fraction (AWM-f), T1 and T2 lesion loads, and significant lower WM-f, and GM-f. Multivariate analysis showed that high FSS was significantly associated with lower WM-f, and GM-f. Females and highly educated patients were significantly less fatigued.

CONCLUSION

These results suggest that among MS patients with low disability those with high-fatigue show higher WM and GM atrophy and higher lesion load, and that female sex and higher levels of education may play a protective role towards fatigue. Furthermore, they suggest that in MS, independent of disability, WM and GM atrophy is a risk factor to have fatigue.

Inflammatory demyelination and neurodegeneration in early multiple sclerosis

A number of recent magnetic resonance imaging studies have challenged the classical view of multiple sclerosis (MS) as a "two-stage" disease where an early inflammatory demyelinating phase with focal macroscopic lesions formed in the white matter (WM) of the central nervous system is followed by a late neurodegenerative phase, which is believed to be a mere consequence of repeated inflammatory insults and irreversible demyelination. These studies have consistently shown the presence of diffuse normal-appearing WM damage, marked gray matter involvement and significant cortical functional reorganization, as well as the occurrence of the neurodegenerative component of MS from the earliest clinical stages of the disease with only a partial relation to MRI markers of inflammatory demyelination. The present review argues that MS can no longer be viewed as a "two-stage" disease, which suggests that the two pathological components are dissociated in time, but rather as a "simultaneous two-component" disease, where the relative contributions of the various pathological processes of the disease to the development of "fixed" disability, their relationship and their evolution over time need to be clarified. This new view of MS should inform the development of future research protocols to define its actual physiopathology and prompt the institution of early treatment which should ideally target not only inflammatory demyelination, but also the neurodegenerative aspects of the disease, as well as promote neuroprotection and enhance reparative mechanisms and adaptive functional reorganization of the cortex.

MR diffusion changes correlate with ultra-structurally defined axonal degeneration in murine optic nerve

Diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) are widely used to investigate central nervous system (CNS) white matter structure and pathology. Changes in principal diffusivities parallel and perpendicular to nerve fibers or axonal tracts have been associated with axonal pathology and de/dysmyelination respectively. However, the ultra-structural properties and the pathological alterations of white matter responsible for diffusivity changes have not been fully elucidated. We examined the relationship between the directional diffusivities and ultra-structural properties in mouse optic nerve using healthy animals, and mice with optic neuritis (ON) that exhibited marked inflammatory changes and moderately severe axonal pathology. Progressive axonal degeneration in ON resulted in a 23% reduction of parallel diffusivity as detected by diffusion MRI (P<10(-5)), but no change in perpendicular diffusivity. Parallel diffusion changes were highly correlated with the total axolemmal cross-sectional area in the pre-chiasmal portion of the optic nerve (r=0.86, P<0.001). This study provides quantitative evidence that reduced parallel diffusivity in the optic nerve correlates significantly with axolemmal cross-sectional area reductions. MRI-based assessment of axonal degeneration in murine ON is feasible and potentially useful for monitoring of neuro-protective therapies in preclinical trials in animals.

Magnetic resonance spectroscopy and metabolic imaging in white matter diseases and pediatric disorders

This review provides the reader with an overview of the magnetic resonance spectroscopy technique and the clinical, pathological, imaging, and metabolic features for select white matter disorders of interest. With this composite summary, the reader should find it easier to implement and interpret spectroscopy in the clinical setting for the diagnosis and monitoring of patients with white matter disorders.

Effect of early interferon beta-1a therapy on conversion to multiple sclerosis in Iranian patients with a first demyelinating event

BACKGROUND

A new treatment approach to multiple sclerosis (MS) is the initiation of interferon therapy in the early phase of the disease when a patient presents with clinically isolated syndrome.

AIMS OF THE STUDY

The goal of this study was to assess the effect of early treatment on the risk of conversion to clinically definite MS in Iranian patients.

METHODS

Eligible patients had presented with a first episode of neurological dysfunction suggesting MS within the previous 3 months and had abnormal brain magnetic resonance imaging (MRI). Patients were randomly assigned to receive intramuscular interferon beta 1a 30 mug or placebo once a week for 3 years.

RESULTS

Of the 217 patients randomized, 202 patients completed the study; 104 received Avonex and 98 received placebo. Fewer patients converted to clinically definite multiple sclerosis in the treated group than in the placebo group during the study (36.6% vs 58.2%, P < 0.003). The number of active T2-weighted MRI lesions was significantly lower in the treated group.

CONCLUSIONS

The results of our study, which are consistent with those from western studies, show that treatment at an early stage of MS delays conversion to definite MS and has positive effects on MRI outcomes.