MS Abstracts 05d-2g1

Myelin-Oligodendrocyte Glycoprotein (MOG) specific AntiBodies (ABs) are involved in AutoAntiBody-mediated DeMyelination possibly contributing to lesion development in Multiple Sclerosis (MS).

InterLeukin-6 (IL-6) has been reported to play a crucial role for the PathoGenesis of a MOG-induced animal model of MS.

To investigate the link between anti-MOG abs production and IL-6 up-regulation in MS, we determined the presence of Anti-MOG abs and measured concentrations of IL-6 and its soluble receptors (sIL-6RC).

In paired Serum and CerebroSpinal Fluid (CSF) samples of MS patients and Serum samples of age-matched healthy controls (HC), Anti-MOG ABs were detected in 75% of MS Sera, 57% of MS CSF samples and 20% of HC Sera.

There was no difference in IL-6 and sIL-6RC levels between Anti-MOG abs positive and negative samples. Thus, no association between the presence of Anti-MOG ABs and Serum/CSF levels of IL-6/sIL-6RC was found.

Chemokines are small proteins that act as ChemoAttractants and activators in Leukocytes during physiological and inflammatory processes.

In the CNS Chemokine receptors have been shown to be expressed on Neurons, Astrocytes and Microglia but their function in the CNS is poorly understood.

CXCR1 and CXCR2 are receptors for ELR-positive CXC Chemokines which include Growth-Regulated Oncogene alpha (GRO-alpha) and InterLeukin-8 (IL-8).

GRO-alpha is considered to influence proliferation of cultured Oligodendrocyte Progenitors (OLPs). Using RT-PCR we show here that the Oligodendrocyte precursor cell line CG-4 expresses both CXCR1 and CXCR2.

Furthermore we demonstrate that both CG-4 cells and primary cultures of rat OLPs are ImmunoReactive for CXCR2, the potential receptor for GRO-alpha.

This finding demonstrates that the Chemokine receptor system is probably also involved in the regulation of Oligodendroglial Cells.

During developmental processes and may even have implications for inflammatory DeMyelinating Diseases like Multiple Sclerosis.

Myelin is one of the few biological membranes to contain the lipid GalactoCerebrosides, although their role in Myelin is unclear.

To explore its structural role, we used fluorescence and Atomic Force Microscopy (AFM) to study Nonhydroxy GalactoCerebrosides (NCer) at the air-water interface of a Langmuir-Blodgett trough.

Fluorescence microscopy at the air-water interface indicated that NCer forms micrometer scale domains of varying radii with six fractal-like extensions.

Atomic force microscopy using TappingMode in water on samples transferred to mica confirmed the fractal-like domain structure in the absence of dye.

And showed that the domains consisted of many aggregated NanoTubes with a diameter of 30 nm. The Hausdorf fractal dimension was estimated to be 1.26 and 1.11 for two domains imaged with AFM.

This evidence indicates that NCer forms a bulk phase of NanoTubes at the air-water interface, unlike the liquid-condensed phase of a PhosphoLipid monolayer.

That NCer forms bilayer NanoTubes that aggregate strongly suggests NCer helps maintain the stability of Myelin by contributing to the curvature and adhesion of the membrane.

We found that NCer appears to be decreased in Myelin from Multiple Sclerosis Normal-Appearing White Matter, which could be an important event in the loss of Myelin stability.

Copyright 2001 Academic Press.

There is accumulating evidence that InterLeukin-12 (IL-12) is involved in the PathoGenesis of Multiple Sclerosis. In the periphery, this Cytokine is produced by Antigen-Presenting Cells (APCs) following interaction with activated T-Cells.

CD40 ligation plays a crucial role in this production. Microglial Cells are thought to play a major role in Antigen Presentation in the Central Nervous System.

In this work, we examined IL-12 production by human primary Microglial Cells after CD40 ligation. These cells expressed CD40 and MHC Class II following Interferon- activation.

IL-12 p40 mRNA and protein, but not bioactive IL-12 p70, were detected in response to direct CD40 activation.

Microglial Cells co-cultured with activated Allogenic CD4⁺ T-Lymphocytes also produced IL-12 p40 but not IL-12 p70.

This IL-12 p40 production was inhibited by Anti-CD40 Ligand. Altogether, these results suggest that CD40-CD40-Ligand interaction provides a signal that triggers IL-12 p40 expression.

However, other interaction(s) may be required during Antigen Presentation for bioactive heterodimeric IL-12 p70 to be produced by Microglial Cells.

Copyright 2001 Academic Press.

By detecting focal Blood-Brain Barrier (BBB) breakdown, Gadolinium (Gd-DTPA) contrast-enhanced T₁-weighted Magnetic Resonance Imaging (MRI) allows assessment of inflammatory activity in Multiple Sclerosis (MS).

And provides a sensitive means of monitoring ImmunoModulatory therapies in exploratory trials. Serial monthly studies were performed in eight Relapsing/Remitting and eight Secondary/Progressive patients to assess new and more sensitive techniques for enhanced MRI.

Brain and Spine imaging was carried out at 1.5-T on two occasions 24-72 h apart using a conventional imaging protocol with T₁-weighted MRI at single-dose (0.1 mmol/kg) Gd-DTPA.

And a potentially more sensitive "modified" protocol with T₁-weighted MRI at triple-dose (0.3 mmol/kg) Gd-DTPA (with addition of delay and Magnetization Transfer presaturation for Brain imaging).

For each MRI protocol the total numbers of enhancing lesions (97 paired studies) and new enhancing lesions (81 paired studies) were assessed.

The total number of enhancing lesions seen was 347/75 on conventional Brain/Cord MRI respectively, and 754/123 on modified Brain/Cord MRI.

The respective numbers of new enhancing lesions were 168/40 on conventional and 276/71 on modified scans.

Smaller increases were seen in the proportion of active scans using the modified protocol. Sample size calculations showed no reduction in sample sizes required for a parallel group study.

But a reduced sample size for crossover studies using the modified protocol; the addition of Cord to Brain imaging did not improve power for either trial design.

A combined modified Brain and Cord imaging protocol markedly improves the detection of areas of focal BBB leakage in MS and may be useful in selected natural history studies.

The modified Brain protocol reduces sample size requirements for crossover studies but not necessarily for parallel design trials.

The Emotional and relationship problems associated with MS have not always been fully appreciated by the medical profession, which has tended to concentrate on the Physical aspects of this disease.

Yet the Psychological problems of MS often cause more suffering than Physical effects.

Fatigue is a common symptom of patients with Multiple Sclerosis (MS). It is reported by about one-third of patients, and for many Fatigue is the most disabling symptom.

Fatigue may be associated with motor disturbances and/or mood disorders, which makes it very difficult to determine whether the Fatigue is an aspect of these features or a result per se of the disease.

Although peripheral mechanisms have some role in the PathoGenesis of Fatigue, in MS there are clear indications that the more important role is played by "Central" abnormalities.

NeuroPhysiological studies have shown that Fatigue does not depend on involvement of the Pyramidal Tracts and implicate impairment of volitional drive of the Descending Motor Pathways as a PhysioPathological mechanism.

Metabolic abnormalities of the Frontal Cortex and Basal Ganglia revealed by Positron-Emission Tomography and correlations between Fatigue and Magnetic Resonance Imaging lesion burden support this hypothesis.

Some recent studies also suggest that pro-inflammatory Cytokines contribute to the sense of tiredness.

No specific treatments are available. Management strategies include medications, exercise, and behavioral therapy; in most cases a combined approach is appropriate.

The Spinal Cord is a common site of involvement in Multiple Sclerosis (MS), and a major cause of the disability suffered by MS patients.

High quality MRI of the Spinal Cord is therefore important for diagnosis and research. Imaging of the Spine, however, presents many technical difficulties because of the small size of the Spinal Cord and the potential for artifacts.

This article discusses technical difficulties such as pulse sequences, the use of newer imaging techniques, and the application of spinal MR imaging in clinical settings.

Major studies are underway involving Spinal Cord imaging, and clinical trials of disease-modifying agents are beginning to include Spinal Cord imaging, especially measurements of Atrophy, as part of their protocols.

In clinical practice, Spinal Cord imaging is essential for ruling out other causes of Myelopathies, particularly Spinal Cord compression.

And can help in the diagnosis of MS when Brain imaging is normal, or in older individuals in whom findings in the Brain are less specific.

Gadolinium (Gd)-enhanced MR imaging has greatly improved the understanding of the PathoPhysiology of Multiple Sclerosis (MS) and has provided robust outcome measures for monitoring MS activity.

Modest correlation between the presence and extent of enhancement and the evolution of MS probably owes to the limited sensitivity and specificity of conventional Gd-enhanced MRI.

Triple dose of Gd may enable better assessment of the presence and extent of "low-grade" MS inflammation.

Cell-specific imaging techniques and multiparametric MRI studies should increase understanding of the pathologic steps between inflammation and irreversible tissue loss.

And consequently, better define the mechanisms leading to irreversible Neurological disability in MS.

Clinical applications of Gd-enhanced MR imaging should include the diagnostic work-up of MS patients, and the assessment of their disease activity over time, in the context of natural history studies or clinical trials.

Gd-enhanced MR imaging should always be obtained at presentation in patients with Clinically Isolated Neurological Syndromes, because of its ability to show the time dissemination of lesions, and its high predictive value for subsequent evolution to Clinically Definite MS.

In patients with established MS, however, the usefulness of Gd-enhanced MR imaging should depend strictly on specific clinical settings or research questions.

Axonal injury in Multiple Sclerosis (MS) is Focal and diffuse, and is directly responsible for irreversible Disability.

Acute inflammatory events can be associated with reversible disability that may parallel reversible Axonal injury. This in part accounts for the remission following relapses early in the disease.

By the time there is clinical disability, substantial Axonal injury already has occurred. This provides a strong rationale for the early limitation of inflammation and its consequences.

MHC Class II heterodimers bind Peptides 12-20 aa in length. The Peptide Flanking Residues (PFRs) of these Ligands extend from a central binding core consisting of nine Amino Acids.

Increasing evidence suggests that the PFRs can alter the ImmunoGenicity of T-Cell Epitopes. We have previously noted that eluted Peptide pool sequence data derived from an MHC Class II Ag reflect patterns of enrichment.

Not only in the core binding region but also in the PFRS: We sought to distinguish whether these enrichments reflect cellular processes or direct MHC-Peptide interactions.

Using the Multiple Sclerosis-associated allele HLA-DR2, pool sequence data from naturally processed Ligands were compared with the patterns of enrichment obtained by binding SemiCombinatorial Peptide libraries to empty HLA-DR2 molecules.

Naturally processed Ligands revealed patterns of enrichment reflecting both the binding motif of HLA-DR2 (position (P)1, aliphatic; P4, bulky hydrophobic; and P6, polar).

As well as the nonbound flanking regions, including acidic residues at the N terminus and basic residues at the C terminus.

These PFR enrichments were independent of MHC-Peptide interactions.

Further studies revealed similar patterns in nine other HLA alleles, with the C-terminal basic residues being as highly conserved as the previously described N-terminal prolines of MHC Class II Ligands.

There is evidence that addition of C-terminal basic PFRs to known Peptide Epitopes is able to enhance both processing as well as T-Cell activation.

Recognition of these allele-transcending patterns in the PFRs may prove useful in Epitope identification and vaccine design.