MS Abstracts 01b-2g5

Imaging studies in Multiple Sclerosis have shown that Spinal Cord Atrophy correlates with clinical disability. The pathological substrate of Atrophy has not as yet been investigated adequately.

In order to determine the cause of Spinal Cord Atrophy in Multiple Sclerosis, five different sections of the Spinal Cord were examined HistoPathologically in 33 controls and 55 Multiple Sclerosis cases.

In the Multiple Sclerosis cases in each section the total lesion load and the Cross-Sectional Area of the Cord were measured.

Multiple regression models were estimated, controlling for sex, age, duration of the disease and location of the Cord sections. The Multiple Sclerosis Cords were found to be significantly smaller than the controls.

The duration of the disease played the most important role in determining Cord Atrophy. The degree of Atrophy varied in different parts of the Cord. Individual lesions played a minor role in local Atrophy.

Our findings suggest that Axonal Degeneration, possibly caused by the cumulative number of lesions in the Brain and Cord, or an alternative Atrophic process, is responsible for Spinal Cord Atrophy in Multiple Sclerosis, rather than tissue loss within individual lesions.

In this Mini-Review we present a new hypothesis in support of the NeuroDegenerative theory as a mechanism for the pathogenesis of Multiple Sclerosis (MS). The pathogenesis of MS results from changes in two distinct CNS compartments.

These are the "Myelin" and "NonMyelin" compartments. The Myelin compartment is where primary DeMyelination, amidst attempts at ReMyelination, is superseded in the CNS by ongoing disease.

Recent evidence obtained via Magnetic Resonance Imaging and Spectroscopy techniques supports the view that the Normal-Appearing White Matter (NAWM) in the MS Brain is altered. Several biochemical changes in NAWM have been determined.

These include the Cationicity of Myelin Basic Protein (MBP) as a result of the action of Peptidyl ArginineDeiminase (PAD) activity converting Arginyl residues to Citrulline.

The accompanying loss of positive charge makes Myelin susceptible to Vesiculation and MBP more susceptible to ProteoLytic activity.

An increase of MBP AutoCatalysis in the MS Brain might also contribute to the generation of ImmunoDominant Epitopes. Accompanying the destruction of Myelin in the Myelin compartment is the activation of Astrocytes and Microglia.

These contribute to the inflammatory response and T-Cell activation leading to AutoImmunity. The complex environment that exists in the DeMyelinating Brain also affects the "NonMyelin" compartment.

The inappropriate up-regulation of molecules, including those of the Jagged-1-Notch-1 signal transduction pathway, affects Oligodendrocyte Precursor Cell (OPC) differentiation.

Other effectors of Oligodendrocyte maturation include Stathmin, a Microtube-destabilizing protein, which prevents healing in the DeMyelinating Brain.

The hypothesis we present suggests a therapeutic strategy that should:
1. Target the effectors within the Myelin compartment
2. Enable resident OPC maturation in the NonMyelin compartment, allowing for effective repair of Myelin loss

The net effect of this new therapeutic strategy is the modification of the disease environment and the stimulation of healing and repair.

(c) 2005 Wiley-Liss, Inc.

Optic Neuritis presentations are thought to have a better prognosis. The aim of our study was to compare conversion to Multiple Sclerosis on the different topographies of CISs.

We prospectively evaluated 320 patients with CISs (123 with Optic Neuritis, 78 with BrainStem Syndromes, 89 with Spinal Cord Syndromes, and 30 with other topographies) who were observed for a median of 39 months.

Patients underwent Brain MRI within 3 months of their first attack and again 12 months later. Conversion to Multiple Sclerosis determined either clinically or by MRI was evaluated according to topography.

Baseline MRI was normal in 49.2% of patients with Optic Neuritis compared with 24% in BrainStem Syndromes, 24% in Spinal Cord Syndromes, and 18.5% in other syndromes.

Optic Neuritis behaved differently from the other CISs for lower conversion to Clinically Definite Multiple Sclerosis and smaller proportion of patients fulfilling MRI dissemination in space, time, or both.

Nevertheless, when only patients with abnormal Cranial MRI results at baseline were selected, no differences for clinical or MRI conversion were found.

Optic Neuritis has a smaller risk for conversion to Multiple Sclerosis. Nevertheless, MRI at baseline, not CIS topography, appears to be the crucial issue at Multiple Sclerosis presentation.

Ann Neurol 2005;57:210-215.

The purpose of this paper is to report CerebroSpinal Fluid (CSF) findings in Multiple Sclerosis (MS) from our laboratory, to discuss the implications of CSF abnormalities in terms of diagnosis.

Paired CSF-Serum samples from of 1533 on 3893 patients with suspected Neurological Diseases over a 10 year period were analysed by routine laboratory microscopy and assays of ImmunoGlobulin G by IsoElectric Focusing for the detection of Intrathecal OligoClonal IgG.

Patients were grouped further into four headings according to their disorders:

1. MS (625 cases)according to Poser
   • Definite (246 cases) Probable (123 cases) and Possible (256 cases)
2. Other Inflammatory Neurological Diseases (91 cases)
3. Various Non-Inflammatory Neurological Disorders (732 cases)
4. Uncertain Neurological Disorders (85 cases)

Definite MS group (16%) was compared to Non-Inflammatory Neurological Disorders (48%). Important signs for activity of Multiple Sclerosis are observed. Cell counts were 10/mul in 71% (N < == 2/mul).

Inflammatory cytology is observed after concentration and CytoCentrifugation on slides with activated B-Lymphocytes, Lymphoplasmocytes and/or Plasmocytes (76%).

Total protein concentration is increased in 37% (N < 0.40g/l), CSF/Serum Albumin quotient with age dependent references for the Blood-CSF Barrier dysfunction is increased in 26% (N < 0.65 x 10(-2)).

IgG index for Intrathecal synthesis of IgG is increased in 69% (N < 0.70), sensitive detection of OligoClonal IgG restricted to CSF by IsoelEctric Focusing is positive in 91% (86-96%) with a specificity of 96% (93-99%).

A major challenge in Multiple Sclerosis research is to understand the cause or causes of ReMyelination failure and to devise ways of ameliorating its consequences. This requires appropriate experimental models.

Although there are many models of acute DeMyelination, at present there are few suitable models of chronic DeMyelination. The taiep rat is a Myelin mutant that shows progressive Myelin loss and, by 1 year of age.

Its CNS tissue has many features of chronic areas of DeMyelination in Multiple Sclerosis: chronically DeMyelinated Axons present in an Astrocytic environment in the absence of acute inflammation.

Using the taiep rat and a combination of X-irradiation and cell transplantation, it has been possible to address a number of questions concerning ReMyelination failure in chronic Multiple Sclerosis lesions.

Such as whether chronically DeMyelinated Axons have undergone changes that render them refractory to ReMyelination and why ReMyelination is absent when Oligodendrocyte Progenitor Cells (OPCs) are present.

Our experiments show that:

1. Transplanted OPCs will not populate OPC-containing areas of chronic DeMyelination
2. Myelination competent OPCs can repopulate OPC-depleted, chronically DeMyelinated, Astrocytosed tissue
   • But this repopulation does not result in ReMyelination
     • - closely resembling the situation found in some Multiple Sclerosis plaques
3. The induction of acute inflammation in this Non-ReMyelinating situation results in ReMyelination.

Thus, we can conclude that Axonal changes induced by chronic DeMyelination are unlikely to contribute to ReMyelination failure in Multiple Sclerosis.

Rather, ReMyelination fails either because OPCs fail to repopulate areas of DeMyelination or because if OPCs are present they are unable to generate ReMyelinating Oligodendrocytes.

Owing to the presence of inhibitory factors and/or a lack of the stimuli required to activate these cells to generate ReMyelinating Oligodendrocytes. This Non-ReMyelinating situation can be transformed to a ReMyelinating one by the induction of acute Inflammation.

The Cytokine IL-21 is closely related to IL-2 and IL-15, a Cytokine family that uses the common gamma-chain for signaling. IL-21 is expressed by activated CD4⁺ T-Cells.

We examined the role of IL-21 in the AutoImmune Disease Experimental Autoimmune Encephalomyelitis (EAE), an animal model for human Multiple Sclerosis.

IL-21 administration before induction of EAE with a NeuroAntigen, Myelin Oligodendrocyte Glycoprotein Peptide 35-55, and adjuvant enhanced the inflammatory influx into the CNS.

As well as the severity of EAE, Autoreactive T-Cells purified from IL-21-treated mice transferred more severe EAE than did the control Encephalitogenic T Cells.

No such effects were observed when IL-21 was administered after EAE progressed. Additional studies demonstrated that IL-21 given before the induction of EAE boosted NK Cell function, including secretion of IFN-γ.

Depletion of NK Cells abrogated the effect of IL-21. Therefore, IL-21, by affecting NK Cells, has differential effects during the initiation and progression of AutoImmune responses against NeuroAntigens.

Multiple Sclerosis is the most common Inflammatory DeMyelinating Disease of the Central Nervous System and is the leading cause of non traumatic Neurological disability in young adults.

In recent years it has become increasingly evident that Axonal degeneration is a key player in the pathogenesis of disability in MS but the mechanisms that lead to Axonal Damage are not fully understood.

It seems likely that the causes of Axonal Damage vary at different stages of the disease and several theories have evolved that address the mechanisms leading to Axonal Loss in the acute stages of DeMyelination.

There has been relatively little attention given to investigation of the mechanisms involved in chronic Axonal Loss in the Progressive stages of MS.

We propose a hypothesis that Mitochondria play a key role in this chronic Axonal Loss.

Following DeMyelination there is redistribution of Sodium Channels along the Axon and Mitochondria are recruited to the DeMyelinated regions, to meet the increased energy requirements necessary to maintain Conduction.

The Mitochondria present within the chronically DeMyelinated Axons will be functioning at full capacity. The Axon may well be able to function for many years due to these adaptive mechanisms

But, we propose that eventually, despite AntiOxidant defences, free radical damage will accumulate and Mitochondrial function will become compromised.

ATP concentration within the Axon will decrease and the effect on Axonal function will be profound.

The actual cause of cell death could be due to a number of mechanisms related to Mitochondrial dysfunction including failure of Ionic homeostasis, Calcium influx, Mitochondrial mediated cell death or impaired Axonal Transport.

Whatever the cause of Axonal Loss our hypothesis is that Mitochondria are central to this process.

We explore steps to test this hypothesis and discuss the possible therapeutic approaches which target the Mitochondrial mechanisms that may contribute to chronic Axonal loss.

Functional imaging studies have demonstrated a relationship between Fatigue and altered Cerebral activation patterns in Multiple Sclerosis patients, but no relationship between Fatigue and Brain Atrophy has been demonstrated.

We hypothesized that the subjective complaint of Fatigue would predict the severity of destructive Brain pathology.

We assessed the relationship between Fatigue and Brain Atrophy longitudinally.

In a cohort of 134 patients previously enrolled in a 2-year clinical trial of Interferon-beta-1a and re-evaluated 8 years after randomization into the trial.

Brain Atrophy was measured using the Brain Parenchymal Fraction (BPF), and disability was measured using the Multiple Sclerosis Functional Composite at baseline, year 2 and year 8.

Fatigue was measured using the Sickness Impact Profile's Sleep and Rest Scale (SIPSR) at baseline, year 2 and year 8.

Linear regression analyses were used to assess the relationship between changes in Fatigue and Atrophy progression.

Worsening Fatigue on the SIPSR during the initial 2 years was significantly associated with progressive Brain Atrophy over the subsequent 6 years.

The relationships between Fatigue and Brain Atrophy were independent of changes in disability, mood, or other MRI characteristics.

This suggests that the subjective complaint of Fatigue is linked to destructive pathologic processes in RRMS patients.

The incidence of the NeuroPathological lesions and the severity of the clinical symptoms in Multiple Sclerosis (MS) are correlated with the amount of the transferred AutoTeactive T-Cells.

The balance between the T-helper 1 (Th1) and T-helper 2 (Th2) Cytokine phenotypes may affect the activity of the disease in MS patients. InterLeukin-10 (IL-10) is a Cytokine secreted by Th2 cells.

Thus, it has been thought that inducing IL-10 may have therapeutic effects in the treatment of MS patients. In this study, in order to determine whether different types of prophylaxis change the secretion of IL-10.

We measured the levels of IL-10 in Relapsing/Remitting Multiple Sclerosis (RRMS) patients receiving Interferon-beta-1b (IFN-ß-1b ) or Azathioprine (AZA).

Our study consisted of RRMS patients (n = 45) and healthy subjects (n = 15) as control group.

Patients were categorized into three groups as those receiving either IFN-ß-1b or AZA and those not receiving prophylaxis. Each group was compared with the control group.

Serum IL-10 levels were determined using ELISA method. IL-10 levels of those receiving IFN-ß-1b were found to be significantly higher than that of other groups.

These results support that the ability of inducing AntiInflammatory Cytokine IL-10 plays a role in the clinical advantage of IFN-ß-1b in MS treatment.

Background And Purpose
Progressive Brain Atrophy is a well-known feature of Multiple Sclerosis (MS). We characterized the spatial evolution of Atrophy in different MS phenotypes.

Methods
Dual-echo and T₁-weighted MR images were obtained in 70 patients with MS and 10 healthy control subjects at entry and after 15 months.

Within-group changes in regional Atrophy were assessed by applying Structural Image Evaluation Using Normalization of Atrophy software and statistical parametric mapping analysis. Reported differences are for P < .001>.

Results
During follow-up, patients with Relapsing/Remitting MS (RRMS) differences significant Atrophy around the Ventricular System; PeriCerebellar Spaces; Cerebellar Tentorium; Putamen; Corpus Callosum; Cingulate Sulcus; Hippocampus; Parieto-Occipital Fissure; Lateral Fissure; and Frontal, Parietal, Temporal, and Occipital Cortex.

Patients with Secondary/Progressive MS developed significant Atrophy of the Cingulate Sulcus; Pulvinar; Caudate Nucleus; Anterior Orbital Gyrus; Mammillary Body; Fourth Ventricle; and regions of Frontal, Parietal, Temporal, and Occipital Cortex.

Patients with Primary/Progressive MS developed significant Atrophy of the BiLateral Central Sulcus; Caudate Nucleus; PrePontine and Quadrigeminal Cisterns; Lateral Ventricles; and regions of Frontal, Parietal, Temporal, and Occipital Cortex.

In all phenotypes, the development of Atrophy in some regions was significantly correlated with the accumulation of T₂- and T₁-visible lesions and clinical disability (r = -0.57 to -0.86).

Conclusion
In MS, Brain Atrophy develops involving different structures in the different phenotypes.

While Ventricular Enlargement is predominant in RRMS, Cortical Atrophy seems to be more important in the Progressive forms.

Measures of Regional Brain Atrophy were significantly correlated with disability, suggesting that this approach is promising for bridging the gap between clinical and MR imaging findings in MS.

The purpose of this paper is to perform quantitative measurements of the Magnetization Transfer Rate (k-for) and native T₁ relaxation time (T₁free) in the Brain Tissue of normal individuals and patients with Multiple Sclerosis (MS).

By means of multiple gradient echo acquisitions, and to correlate these measurements with the Magnetization Transfer Ratio (MTR).

Quantitative Magnetization Transfer imaging was performed in five normal volunteers and 12 patients with Relapsing/Remitting MS on a 1.5 T Magnetic Resonance (MR) scanner.

The T₁ relaxation time under Magnetization Transfer irradiation (T₁sat) was calculated by means of fitting the signal intensity over the flip angle in several 3D spoiled gradient echo acquisitions (3 degrees, 15 degrees, 30 degrees, and 60 degrees ).

While a single acquisition without MT irradiation (flip angle of 3 degrees ) was utilized to calculate the MTR. The k-for and T₁free constants were quantified on a pixel-by-pixel basis and parametric maps were reconstructed.

We performed 226 measurements of k-for, T₁free, and the MTR on Normal White Matter (NWM) of healthy volunteers (n=50), and Normal-Appearing White Matter (NAWM) and pathological Brain areas of MS patients (n=120 and 56, respectively).

Correlation coefficients between k-for-MTR, T₁free-MTR, and T₁free-k-for were calculated.

Lesions were classified, according to their characteristics on T₁-weighted images, into:

1. IsoIntense (compared to White Matter)
2. Mildly HypoIntense, showing signal intensity
   • Lower than White Matter and higher than Gray Matter
3. Severely HypoIntense, revealing signal intensity
   • Lower than Gray Matter

"Dirty" White Matter (DWM) corresponded to areas with diffused high signal, as identified on T₂-weighted images.

Strong correlation coefficients were obtained between MTR and k-for for all lesions studied (r(2)=0.9, p < 0.0001), for mildly HypoIntense plaques (r(2)=0.82, p < 0.0001), and for DWM (r(2)=0.78, p=0.0007).

In contrast, comparison between MTR and T₁free values yielded rather low correlation coefficients for all groups assessed.

In severely HypoIntense lesions, an excellent correlation was found between k-for and T₁free measurements (r(2)=0.98, p < 0.0001).

Strong correlations between k-for and T₁free were found for the rest of the subgroups, except for the NAWM, in which a moderate correlation was obtained (r(2)=0.5, p < 0.0001).

We conclude that k-for and T₁free measurements are feasible and may improve our understanding of the pathological Brain changes that occur in MS patients.

Background And Objective
Our goal was to evaluate the relation between the presence of Neutralizing AntiBodies (NABs) to Interferon-ß-1b in Multiple Sclerosis (MS) patients and the clinical evolution in the following years.

Patients And Method
As we previously reported, we tested NABs in 68 patients treated with Interferon-ß-1b after 2 years of treatment.

We prospectively followed this cohort every three months for a minimum period of 6 years collecting data about relapses, disability, secondary effects and dropouts.

Results
During the 6 year follow-up period, the annualized relapse rate did not differ between patients with and patients without NABs.

A sustained progression was observed in 33% of positive patients and in 38% of patients without NABs. No differences were found in the proportion of patients who reached an EDSS score of 6. Secondary effects were similar in both groups.

Conclusions
Although our results do not vouch for a negative effect of the presence of NABs on the clinical evolution of MS patients treated with Interferon-ß.

Further longitudinal studies to clarify the real effect of the presence of NABs in these patients are still much needed.