Dirty-appearing white matter in multiple sclerosis: preliminary observations of myelin phospholipid and axonal loss.

"Dirty-appearing white matter" (DAWM) in multiple sclerosis (MS) is defined as a region(s) with ill-defined borders of intermediate signal intensity between that of normal-appearing white matter (NAWM) and that of plaque on T(2)-weighted and proton density imaging. To delineate the histopathology of DAWM, four formalin-fixed cerebral hemisphere slices of three MS patients with DAWM were scanned with T(2)- weighted and proton density sequences. The myelin water fraction (MWF) was obtained by expressing the short T(2) component as a fraction of the total T(2) distribution. Hemispheric sections were then stained with Luxol fast blue (LFB) for myelin phospholipids, for myelin basic protein (MBP) and 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) for myelin; Bielschowsky silver impregnation for axons; and for glial fibrillary acidic protein (GFAP) for astrocytes. Compared to NAWM, DAWM showed reduction in MWF, corresponding to a reduction of LFB staining. DAWM also showed reduced Bielschowsky staining. Quantitatively, the change in MWF in DAWM most consistently correlated with the change in LFB staining. The findings of this preliminary study suggest that DAWM is characterized by loss of myelin phospholipids, detected by the short T(2) component, and axonal reduction.

A Phase II study of the safety and efficacy of teriflunomide in multiple sclerosis with relapses.

BACKGROUND: Teriflunomide, a dihydro-orotate dehydrogenase inhibitor, has immunomodulatory effects, including the ability to suppress experimental allergic encephalomyelitis. In this randomized, double-blind, placebo-controlled Phase II study, the authors examined the safety and efficacy of oral teriflunomide in multiple sclerosis (MS) with relapses. METHODS: Patients (n = 179) with relapsing-remitting MS (n = 157) or secondary progressive MS with relapses (n = 22) were randomized to receive placebo, teriflunomide 7 mg/day, or teriflunomide 14 mg/day for 36 weeks. MRI brain scans were performed every 6 weeks. The primary endpoint was the number of combined unique active lesions per MRI scan. Secondary endpoints included MRI-defined disease burden, relapse frequency, and disability increase. RESULTS: The median number of combined unique active lesions per scan was 0.5, 0.2, and 0.3 in the placebo, teriflunomide 7 mg/day (p < 0.03 vs placebo), and teriflunomide 14 mg/day (p < 0.01 vs placebo) groups during the 36-week double-blind treatment phase. Teriflunomide-treated patients also had significantly fewer T1 enhancing lesions per scan, new or enlarging T2 lesions per scan, and new T2 lesions. Patients receiving teriflunomide 14 mg/day had significantly reduced T2 disease burden. Teriflunomide treatment resulted in trends toward a lower annualized relapse rate and fewer relapsing patients (14 mg/day only) vs placebo. Significantly fewer patients receiving teriflunomide 14 mg/day vs placebo demonstrated disability increase. Treatment was well tolerated; numbers of adverse events and serious adverse events were similar in all treatment groups. CONCLUSION: Oral teriflunomide was effective in reducing MRI lesions and was well tolerated in patients with relapsing multiple sclerosis.

Myelin water imaging in multiple sclerosis: quantitative correlations with histopathology.

Various magnetic resonance (MR) techniques are used to study the pathological evolution of demyelinating diseases, such as multiple sclerosis (MS). However, few studies have validated MR derived measurements with histopathology. Here, we determine the correlation of myelin water imaging, an MR measure of myelin content, with quantitative histopathologic measures of myelin density. The multi-component T2 distribution of water was determined from 25 formalin-fixed MS brain samples using a multi-echo T2 relaxation MR experiment. The myelin water fraction (MWF), defined as T2 signal below 30 milliseconds divided by the total signal, was determined for various regions of interest and compared to Luxol fast blue (myelin stain) mean optical density (OD) for each sample. MWF had a strong correlation with myelin stain [mean (range) R2 = 0.67 (0.45-0.92)], validating MWF as a measure of myelin density. This quantitative technique has many practical applications for the in vivo monitoring of demyelination and remyelination in a variety of disorders of myelin.

Water content and myelin water fraction in multiple sclerosis. A T2 relaxation study.

BACKGROUND: Measurements of the T2 decay curve provide estimates of total water content and myelin water fraction in white matter in-vivo, which may help in understanding the pathological progression of multiple sclerosis (MS). METHODS: Thirty-three MS patients (24 relapsing remitting, 8 secondary progressive, 1 primary progressive) and 18 controls underwent MR examinations. T2 relaxation data were acquired using a 32-echo measurement. All controls and 18 of the 33 MS patients were scanned in the transverse plane through the genu and splenium of the corpus callosum. Five white matter and 6 grey matter structures were outlined in each of these subjects. The remaining 15 MS patients were scanned in other transverse planes. A total of 189 lesions were outlined in the MS patients. Water content and myelin water fraction were calculated for all regions of interest and all lesions. RESULTS: The normal appearing white matter (NAWM) water content was, on average, 2.2% greater than that from controls, with significant differences occurring in the posterior internal capsules, genu and splenium of the corpus callosum, minor forceps and major forceps (p<0.0006). On average, MS lesions had 6.3% higher water content than contralateral NAWM (p<0.0001). Myelin water fraction was 16% lower in NAWM than for controls, with significant differences in the major and minor forceps, internal capsules, and splenium (p<0.05). The myelin water fraction of MS lesions averaged 52 % that of NAWM. CONCLUSIONS: NAWM in MS has a higher water content and lower myelin water fraction than control white matter. The cause of the myelin water fraction decrease in NAWM could potentially be due to either diffuse edema, inflammation, demyelination or any combination of these features. We present a simple model which suggests that myelin loss is the dominant feature of NAWM pathology.

The use of mitoxantrone (Novantrone) for the treatment of multiple sclerosis: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

Mitoxantrone is the first drug approved for the treatment of secondary progressive multiple sclerosis (SPMS) in the United States. This assessment considers use of mitoxantrone in the treatment of MS. Mitoxantrone probably reduces the clinical attack rate and reduces attack-related MRI outcomes in patients with relapsing MS (Type B recommendation). Also, mitoxantrone may have a beneficial effect on disease progression in patients with MS whose clinical condition is worsening (Type B recommendation). The potential for serious toxicity of mitoxantrone, however, must be taken into account when considering this therapy in individual patients. Moreover, because the potential clinical benefits on disease progression appear to be only modest, the results of the single phase III trial should be replicated in another (and hopefully much larger) clinical study before this agent is widely recommended for the treatment of patients with MS.

Genetic susceptibility to MS: a second stage analysis in Canadian MS families.

Four published genome screens have identified a number of markers with increased sharing in multiple sclerosis (MS) families, although none has reached statistical significance. One hundred and five markers previously identified as showing increased sharing in Canadian, British, Finnish, and American genome screens were genotyped in 219 sibling pairs ascertained from the database of the Canadian Collaborative Project on Genetic Susceptibility to MS (CCPGSMS). No markers examined met criteria for significant linkage. Markers located at 5p14 and 17q22 were analyzed in a total of 333 sibling pairs and attained mlod scores of 2.27 and 1.14, respectively. The known HLA Class II DRB1 association with MS was confirmed (P<0.0001). Significant transmission disequilibrium was also observed for D17S789 at 17q22 (P=0.0015). This study highlights the difficulty of searching for genes with only mild-to-moderate effects on susceptibility, although large effects of specific loci may still be present in individual families. Future progress in the genetics of this complex trait may be helped by (1) focussing on more ethnically homogeneous samples, (2) using an increased number of MS families, and (3) using transmission disequilibrium analysis in candidate regions rather than the affected relative pair linkage analysis.

Heme oxygenase-1 plays an important protective role in experimental autoimmune encephalomyelitis.

Increasing evidence shows that oxidative stress plays an important role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of the human disease, multiple sclerosis (MS). Heme oxygenase-1 (HO-1) is a heat shock protein induced by oxidative stress. HO-1 metabolizes heme to the antioxidant bilirubin and carbon monoxide, and represents a powerful endogenous defensive mechanism against free radicals in many diseases. However, the role of this important enzyme in EAE remains unknown. In this study, we showed high expression of HO-1 in lesions of EAE, and demonstrated that hemin, an inducer of HO-1, inhibited EAE effectively. In contrast, tin mesoporphyrin, an inhibitor of HO-1, markedly exacerbated EAE. Our results suggest that endogenous HO-1 plays an important protective role in EAE, and that targeted induction of HO-1 overexpression may represent a new therapy for the treatment of multiple sclerosis.

Recommended diagnostic criteria for multiple sclerosis: guidelines from the International Panel on the diagnosis of multiple sclerosis.

The International Panel on MS Diagnosis presents revised diagnostic criteria for multiple sclerosis (MS). The focus remains on the objective demonstration of dissemination of lesions in both time and space. Magnetic resonance imaging is integrated with dinical and other paraclinical diagnostic methods. The revised criteria facilitate the diagnosis of MS in patients with a variety of presentations, including "monosymptomatic" disease suggestive of MS, disease with a typical relapsing-remitting course, and disease with insidious progression, without clear attacks and remissions. Previously used terms such as "clinically definite" and "probable MS" are no longer recommended. The outcome of a diagnostic evaluation is either MS, "possible MS" (for those at risk for MS, but for whom diagnostic evaluation is equivocal), or "not MS."

Randomized controlled trial of interferon-beta-1a in secondary progressive MS: MRI results.

OBJECTIVE: To examine MRI changes resulting from treatment of secondary progressive MS (SPMS) with two doses of interferon-beta-1a (Rebif). BACKGROUND: Interferon-beta (IFN-beta) reduces relapses and delays progression in relapsing-remitting MS, but there are conflicting results on its clinical benefit in SPMS. METHODS: In a double-blind, randomized, multicenter, placebo-controlled study (SPECTRIMS), 618 patients received IFN-beta-1a 22 microg, 44 microg, or placebo subcutaneously three times weekly for 3 years. T2 activity and burden of disease (BOD) were measured in 617 patients by using semiannual proton density/T2-weighted (PD/T2) MRI scans. A cohort of 283 patients also had 11 monthly PD/T2 and T1-weighted gadolinium-enhanced (T1-Gd) scans at study start. RESULTS: Treatment reduced median numbers of active lesions per patient per scan (semiannual T2 activity: 0.17, 0.20 and 0.67 for the high dose, low dose, and placebo, p < 0.0001; monthly combined unique activity [T1+T2]: 0.11, 0.22, and 1.00, p < 0.0001) and accumulation of BOD (percent change from baseline to month 36: -1.3, -0.5, and 10.0 for the high dose, low dose, and placebo, respectively; p = 0.0001). MRI benefit was most evident in the subgroup of patients who reported relapses in the 2 years before the study. Neutralizing antibody development was associated with reduction in treatment effect: antibody-positive patients did not show significant differences from placebo at either dose. CONCLUSIONS: Interferon-beta-1a used in SPMS showed significant effects on all MRI measures, particularly in patients with relapses in the 2 years before the study.

A pathology-MRI study of the short-T2 component in formalin-fixed multiple sclerosis brain.

OBJECTIVE: To determine the pathologic basis of areas not exhibiting signal of the short-T2 component of the T2 relaxation distribution in MS, as studied in formalin-fixed brain. BACKGROUND: A myelin-specific MRI signal would be of great importance in assessing demyelination in patients with MS. Evidence indicates that the short-T2 (10 to 50 millisecond) component of the T2 relaxation distribution originates from water in myelin sheaths. The authors present two cases of MS in which the anatomic distribution of the short-T2 component was correlated with the pathologic findings in postmortem formalin-fixed brain. METHOD: One half of the formalin-fixed brain was suspended in a gelatin-albumin mixture cross-linked with glutaraldehyde, and scanned with a 32-echo MRI sequence. The brain was then cut along the center of the 5-mm slices scanned, photographed, dehydrated, and embedded in paraffin. Paraffin sections, stained with Luxol fast blue and immunocytochemically for 2',3'-cyclic nucleotide 3'-phosphohydrolase for myelin and by the Bielschowsky technique for axons, were compared with the distribution of the amplitude of the short-T2 component of the comparable image slices. RESULTS: The anatomic distribution of the short-T2 component signal corresponded to the myelin distribution. Chronic, silent MS plaques with myelin loss correlated with areas of absence of short-T2 signal. The numbers of axons within lesions were reduced, but many surviving axons were also seen in these areas of complete loss of myelin. CONCLUSION: In formalin-fixed MS brains the short-T2 component of the T2 relaxation distribution corresponds to the anatomic distribution of myelin. Chronic, silent demyelinated MS plaques show absence of the short-T2 component signal. These results support the hypothesis that the short-T2 component originates from water related to myelin.-1510

Effect of interferon beta-1b in MS: assessment of annual accumulation of PD/T2 activity on MRI. UBC MS/MRI Analysis Group and the MS Study Group.

OBJECTIVE: To determine whether the efficacy of interferon beta-1b (IFNbeta-1b) on lesion activity could be shown with annual analysis of MRI. BACKGROUND: Clinical outcomes and MRI burden of disease changes in MS patients in a multicenter double-blind placebo-controlled 5-year trial of IFNbeta-1b have been reported, together with an analysis of 6-weekly MRI activity in a small subgroup during 2 years. MRI activity measurements based on annual scans have not been documented. METHODS: Patients were randomized into three treatment arms: placebo, 1.6 mIU, and 8 mIU IFNbeta-1b self-administered subcutaneously every other day. Active lesions were identified as new, enlarging, or recurrent on proton density and T2-weighted MRI scans. Gadolinium was not used. An annual accumulation activity index was developed as an additional analysis of lesion activity. RESULTS: During the 5 years, both high- and low-dose IFNbeta-1b groups showed a striking reduction in lesion annual accumulation activity on the activity index versus placebo (p = 0.001). Thirty-five percent of the high-dose patients and 29% of the low-dose patients were MRI inactive by this method of analysis, whereas only 16% of placebo patients were inactive (p = 0.001, placebo versus 8 mIU). CONCLUSIONS: This analysis of the annual accumulation of lesion activity shows that the previously reported treatment effect seen on MRI scanning once every 6 weeks in a subcohort of the patients can also be seen on yearly scans. This annual accumulation activity analysis provides an independent MRI confirmation of a treatment and dose effect for IFNbeta-1b.

T2 hyperintensities: findings and significance.

The hyperintense lesions of multiple sclerosis seen on proton density- and T2-weighted MR images have important clinical and research roles in the diagnosis, follow-up, prognosis, and treatment of the disease.

Magnetic resonance imaging results of the PRISMS trial: a randomized, double-blind, placebo-controlled study of interferon-beta1a in relapsing-remitting multiple sclerosis. Prevention of Relapses and Disability by Interferon-beta1a Subcutaneously in Multiple Sclerosis.

The PRISMS (Prevention of Relapses and Disability by Interferon-beta1a Subcutaneously in Multiple Sclerosis) trial was a double-blind, randomized, multicenter, phase III, placebo-controlled study of interferon-beta1a in 560 patients from 22 centers in 9 countries with clinically definite or laboratory-supported relapsing-remitting multiple sclerosis. The patients were randomized to receive recombinant interferon-beta1a (Rebif), 22 microg (6 mIU), 44 microg (12 mIU), or placebo, given subcutaneously, three times weekly for 2 years. All patients underwent biannual proton density/T2-weighted magnetic resonance imaging scans to determine the overall magnetic resonance imaging disease activity and burden of disease, and a cohort of 205 patients had 11 initial monthly proton density/T2-weighted and gadolinium-enhanced/T1-weighted magnetic resonance imaging scans. Over the 2 years, the placebo group showed a progressive median increase in burden of disease of 10.9%, whereas the 22-microg group and 44-microg group showed median decreases of 1.2% and 3.8%, respectively. The number of T2 active lesions and percentage of scans showing T2 activity on the biannual scans were also significantly reduced in both treatment groups compared with placebo, with a clear dose-effect favoring the 44-microg dose over the 22-microg dose. In the subgroup undergoing initial monthly scanning, this reduction in activity became statistically significant 2 months after the start of treatment. These results provide strong, objective evidence to support the positive clinical results of reduction in relapses and delay in disease progression. In addition, they also demonstrate a significant dosage effect, favoring the 44-microg dose.

The contribution of magnetic resonance imaging to the diagnosis of multiple sclerosis.

MRI is very sensitive in showing MS lesions throughout the CNS. Using MRI for diagnostic purposes, however useful, is a complex issue because of limited specificity of findings and a variety of options as to when, how, and which patients to examine. Comparability of data and a common view regarding the impact of MRI are needed. Following a review of the typical appearance and pattern of MS lesions including differential diagnostic considerations, we suggest economic MRI examination protocols for the brain and spine. Recommendations for referral to MRI consider the need to avoid misdiagnosis and the probability of detecting findings of diagnostic relevance. We also suggest MRI classes of evidence for MS to determine the diagnostic weight of findings and their incorporation into the clinical evaluation. These proposals should help to optimize and standardize the use of MRI in the diagnosis of MS.

Axonal cytoskeleton changes in experimental optic neuritis.

Axonal loss and degeneration in multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE) have been suggested by brain imaging, pathological and axonal transport studies. Further elucidation of the processes and mechanisms of axonal degeneration in demyelinating diseases is therefore of potential importance in order to alleviate the permanent disabilities of MS patients. However, detailed studies in this area are impeded by the small number of reliable models in which the onset and location of demyelination can be well-controlled. In this study, microinjection of polyclonal rabbit anti-galactocerebroside (anti-Gal C) antibody and guinea pig complement was used to induce local demyelination in the rat optic nerve. We found that treatment with appropriate volumes of the antibody and complement could induce local demyelination with minimal pressure- or trauma-induced damage. Local changes in neurofilaments (NFs) and microtubules (MTs) were examined with both immunohistochemistry (IHC) and electron microscopy (EM). On day 1 after microinjection, we observed moderate NF and MT disassembly in the local demyelinated area, although in most cases, no apparent inflammatory cell infiltration was seen. The NF and MT changes became more apparent on days 3, 5, 7 after microinjection, along with gradually increased inflammatory cell infiltration. These results suggested that acute demyelination itself may induce local cytoskeleton changes in the demyelinated axons, and that the ensuing local inflammation may further enhance the axonal damage. When the lesions were stained with specific antibodies for T lymphocytes, macrophages, and astrocytes, we found that most of the cells were macrophages, suggesting that macrophages may play a greater role in inflammation-related axonal degeneration and axonal loss. These results were confirmed and further characterized on the ultrastructural level.