MS Abstracts 04g-2g1

Changes in health policy have underlined the importance of evidence-based clinical practice and rigorous evaluation of patient-based outcomes.

As patient-based outcome measurement is particularly important in treatment trials of Multiple Sclerosis, a number of disease-specific instruments have been developed recently.

One limitation of these instruments is that none was developed using the standard psychometric approach of reducing a large item pool generated from people with Multiple Sclerosis.

Consequently, an outcome measure for clinical trials of Multiple Sclerosis that is disease specific and combines patient perspective with rigorous psychometric methods will complement existing instruments.

The aim of this study was to develop such a measure. Standard psychometric methods were used. A pool of 129 questionnaire items was generated from interviews with 30 people with Multiple Sclerosis, expert opinion and literature review.

The questionnaire was administered by postal survey to 1530 people selected randomly from the Multiple Sclerosis Society membership database. Redundant items and those with limited measurement properties were removed.

The remaining items (n = 41) were grouped into scales using factor analysis, and then refined to form the Multiple Sclerosis Impact Scale (MSIS-29), an instrument measuring the physical (20 items) and psychological (nine items) impact of Multiple Sclerosis.

Five psychometric properties of the MSIS-29 (data quality, scaling assumptions, acceptability, reliability and validity) were examined in a separate postal survey of 1250 Multiple Sclerosis Society members.

A preliminary responsiveness study of the MSIS-29 was undertaken in 55 people admitted for rehabilitation and intravenous Steroid treatment of relapses. The MSIS-29 satisfied all psychometric criteria.

Data quality was excellent, missing data were low (maximum 3.9%), item test-re-test reliability was high (r = 0.65-0.90) and scale scores could be generated for >98% of respondents.

Item descriptive statistics, item convergent and discriminant validity, and factor analysis indicated that it was legitimate to generate scores for MSIS-29 scales by summing items.

MSIS-29 scales showed good variability, small floor and ceiling effects, high internal consistency (Cronbach's alpha </=0.91) and high test-re-test reliability (intraclass correlation </=0.87).

Correlations with other measures and the analysis of group differences provided evidence that the MSIS-29 measures the physical and psychological impact of Multiple Sclerosis.

Effect sizes (physical scale = 0.82, psychological scale = 0.66) demonstrated preliminary evidence of good responsiveness.

These results indicate the MSIS-29 is a clinically useful and scientifically sound patient-based outcome measure of the impact of Multiple Sclerosis suitable for clinical trials and epidemiological studies.

Proton Magnetic Resonance Spectroscopy has shown elevated signals in the Spectral region of Lipids in acute Multiple Sclerosis lesions.

The metabolite-nulling technique allows the separation of macromolecules from other metabolites, such as Lactate, N-AcetylAspartate, Creatine, Choline and Myo-Inositol.

Using this technique in studies on Multiple Sclerosis patients, we were able to differentiate macromolecules biochemically in acute and chronic Multiple Sclerosis lesions.

Ten patients with acute, contrast-enhancing Multiple Sclerosis lesions, 10 patients with chronic lesions and 10 healthy control subjects.

Were investigated with a 1.5 T whole body system, using a Stimulated Echo Acquisition Mode (STEAM) sequence with metabolite-nulling and outer volume saturation.

Metabolites and macromolecules were quantitated absolutely.

The 0.9 and 1.3 parts per million (p.p.m.) resonances of the macromolecules were significantly elevated in acute lesions compared with chronic lesions and healthy controls (P < 0.001 for 0.9 p.p.m., P < 0.05 for 1.3 p.p.m.).

The macromolecular resonances at 2.1 and 3.0 p.p.m. in acute and chronic lesions were normal.

N-AcetylAspartate was significantly reduced in acute and chronic lesions compared with controls (P < 0.05 and P < 0.01, respectively).

Choline was significantly elevated in acute lesions compared with controls (P < 0.05). Up to now, elevated resonances at 0.9 and 1.3 p.p.m. in acute lesions have been interpreted as Lipids.

In metabolite-nulled Spectra, the macromolecular resonances did not fit those of Lipids and might have been due to Proteins or PolyPeptides containing the Amino Acids Alanine, Threonine, Valine, Leucine and Isoleucine.

These account for approximately 40% of the Amino Acids of Myelin ProteoLipid Protein and for approximately 20% of Myelin Basic Protein.

The increased macromolecular resonances at 0.9 and 1.3 p.p.m. may be interpreted as biochemical markers of Myelin fragments.

And may be used as reliable markers of acute Multiple Sclerosis Lesions as they provide clear discrimination among acute and chronic lesions and controls.

Diffusion imaging is a noninvasive technique for measuring the movement of water molecules.

Although it has had its greatest impact thus far in the area of Stroke imaging, the information garnered from Diffusion experiments can provide an indication of Myelin injury and perhaps Axonal integrity.

In this paper, we describe some current and potential future applications of Diffusion imaging in Multiple Sclerosis.

These include the use of global indices such as Diffusion Trace and Anisotropy, as well as implementation of Axonal fiber tracking methodologies for assessment of Axonal integrity and connectivity between Cortical regions.

This paper reviews the current state of knowledge about the use of Diffusion-weighted MRI in the field of Multiple Sclerosis (MS) research.

The contribution that Diffusion-Weighted Imaging has made to our understanding of MS is critically appraised, and pointers are given to the sort of work that needs to be done before Diffusion-weighted MRI could be recommended for inclusion in a clinical trial.

The types of procedures that would be needed for quality assurance of Diffusion data, and the data collection schemes that would lead to reliable data, are then reviewed.

The quantitative nature of diffusion MRI makes it an attractive proposition for inclusion in clinical trials for MS therapeutic agents, but without further validation work with clinical correlates cannot be recommended at present.

Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) provides a unique form of MR contrast that enables the Diffusional motion of water molecules to be quantitatively measured.

As a consequence, DW-MRI provides information about the size, shape, integrity, and orientation of Brain structures.

Pathological processes able to alter tissue integrity by removing or modifying some of the structural barriers that normally restrict water molecular motion in biological tissues cause changes in water Diffusion characteristics, which can be measured in-vivo using DW-MRI.

Although DW-MRI has been shown to be of great clinical utility in the assessment of patients with Cerebral Ischemia, it is also increasingly being used to quantify in-vivo the extent and severity of Multiple Sclerosis (MS) pathology.

The pathological elements of MS have the potential to alter the permeability or geometry of structural barriers to water molecular motion in the Brain, Optic Nerve and Spinal Cord.

The present review outlines the major contributions given by DW-MRI for the quantification of MS-related damage and for the understanding of MS pathophysiology.

Conventional Magnetic Resonance Imaging (MRI) lacks pathological specificity to the heterogeneous substrates of Multiple Sclerosis (MS) lesions.

And is not able to detect subtle, disease-related changes in the Normal-Appearing White Matter (NAWM).

As a consequence, the correlation between MRI findings and the long-term evolution of MS is moderate at best.

To overcome the limitations of conventional MRI, new quantitative Magnetic Resonance (MR) techniques, such as cell-specific imaging, Magnetization Transfer Imaging (MTI), proton Magnetic Resonance Spectroscopy (MRS), Diffusion-Weighted Imaging (DWI) and Functional MRI (fMRI) have all been recently applied to the study of MS.

These techniques should provide more accurate and pathologically specific estimates of the MS lesion burden than conventional MR and should improve our understanding of the mechanisms leading to MS-related irreversible disability.

In order for vaccinations to 'work', the Immune System must be stimulated. The concern that immunizations may lead to the development of AutoImmune Disease (AID) has been questioned.

Since AID occur in the absence of immunizations, it is unlikely that immunizations are a major cause of AID.

Epidemiological studies are needed, however, to assess whether immunizations may increase the risk in some susceptible individuals. This paper discusses the evidence for and against vaccination as a risk factor for AID.

Evidence for immunizations leading to AID come from several sources including animal studies, single and multiple case reports, and Ecologic association.

However more rigorous investigation has failed to confirm most of the allegations.

Unfortunately the question remains difficult to address because for most AIDs, there is limited knowledge of the Etiology, background incidence and other risk factors for their development.

This information is necessary, in the absence of experimental evidence derived from controlled studies, for any sort of adequate causality assessment using the limited data that are available.

Several illustrative examples are discussed to highlight what is known and what remains to be explored, and the type of Epidemiological evidence that would be required to better address the issues.

Examples include the possible association of immunization and Multiple Sclerosis (and other DeMyelinating Diseases), type 1 Diabetes mellitus, Guillain-Barre Syndrome, Idiopathic Thrombocytopenic Purpura, and Rheumatoid Arthritis.

Copyright 2001 Academic Press.

Chronic infections with Hepatitis C Virus (HCV) are associated with various AutoImmune manifestations, i.e mixed Cryoglobulinemia, MembranoProliferative Glomerulonephritis, AutoImmune Thyroid Diseases, Sporadic Porphyria Cutanea Tarda and B-Cell Lymphoma.

Since exacerbation of Hepatitis occurs in 5-10% of HCV patients receiving Interferon-alpha treatment and may be successfully treated by ImmunoSuppression afterwards, Hepatitis C was also suspected to be associated with AutoImmune Hepatitis.

LKM3 AutoAntiBodies in chronic Hepatitis D Virus (HDV) infection and Epitope recognition are discussed. Lately, endogenous and exogenous RetroViruses have been investigated for the induction of AutoImmune Diseases.

Human A type RetroViral particles (HIAP), reverse transcriptase activity and Anti-HIAP AutoAntiBodies were detected in patients with Sjogren's Syndrome.

Anti-HIAP and anti-HIV p24 AutoAntiBodies are seen in Systemic Lupus Erythematosus, Primary Biliary Cirrhosis and Multiple Sclerosis.

Multiple Sclerosis was even associated with a new human RetroVirus called Multiple Sclerosis associated RetroVirus (MSRV).

In Diabetes long terminal repeats (LTR) were detected in the HLA DQB1 locus, which was shown to associate with an increased risk of Diabetes.

A second RetroVirus called IDDMK(1,2)22 was reported to code for a SuperAntigen, which was implicated as a potential cause of Diabetes. This hypothesis, however, was challenged repeatedly.

Until now it is unknown whether endogenous RetroViruses are aetiological agents of AutoImmune Diseases or an Epiphenomenon, induced by coinfecting Viruses (e.g. Herpes Viruses) and inflammatory processes.

Copyright 2001 Academic Press.

The concept of molecular mimicry provides and elegant framework as to how cross-reactivity between Antigens from a foreign agent with self proteins may trigger AutoImmune Diseases.

While it was previously thought that sequence and structural homology between foreign and self proteins or the sharing of T-Cell Receptor (TCR) and MHC-binding motifs are required for molecular mimicry to occur.

We have shown that even completely unrelated Peptide sequences may lead to cross-recognition by T-Cells.

The use of synthetic combinatorial peptide libraries in the positional scanning format (PS-SCL) together with novel biometric prediction approaches has allowed us to describe the recognition profiles of individual AutoReactive T-Cell Clones (TCC) with unprecedented accuracy.

Through studies of Myelin-specific TCC as well as clones from the Nervous System of patients suffering from chronic Central Nervous (CNS) Lyme Disease it has become clear that at least some T-Cells are more degenerate than previously anticipated.

These data will not only help us to redefine what constitutes specific T-Cell recognition, but also allow us to study in more detail the biological role of Molecular Mimicry.

A recent clinical trial with an Altered Peptide Ligand (APL) of one of the candidate Myelin Basic Protein (MBP) Epitopes in MS (Amino Acids 83-99) has shown that such a modified MBP Peptide may not only have therapeutic efficacy, but also bears the potential to exacerbate disease.

Thus, we provide firm evidence that the basic principles of cross-recognition and their PathoGenetic significance are relevant in MS.

Copyright 2001 Academic Press

The mechanism by which Oligodendrocytes are depleted from active lesions in Multiple Sclerosis (MS) is not clear but many reports implicate a CytoLytic process.

The most applied animal model for MS, chronic relapsing Experimental AutoImmune EncephaloMyelitis (EAE), has been established in inbred strains of mice, especially SJL and PL.

Studies on Oligodendrocytes from these strains in vitro have been hampered to date by an inability to grow these cells from mouse CNS tissue.

We report here a successful method to culture SJL mouse Oligodendrocytes and have analyzed lysis (burst) of these cells in vitro mediated by the pore-forming protein, Perforin, a candidate effector molecule in inflammatory DeMyelination.

Cultures were exposed to murine Perforin, 36-72 hemolytic U, for up to 2.5 hr and examined using the Oligodendrocyte phenotypic markers O4, GalactoCerebroside and Myelin Basic Protein (MBP), in addition to a membrane dye (DiI) and a marker of Necrosis, Propidium Iodide, (PI).

Cultures were imaged chronologically by phase contrast, ImmunoFluorescence, digital, light and electron microscopy.

Findings showed that the majority of Oligodendrocytes were killed within 60-90 min via pore expansion and ultimately, membrane disruption.

The structural features of the cellular damage comprised:

1. Swelling of the Cell Body
2. Fenestration and fragmentation of membranes and processes
3. Cytoplasmic vacuolation
4. Breakdown of the nuclear envelope

Astrocytes in the same system were relatively resistant to cell lysis.

The above patterns of Oligodendrocyte damage in SJL Oligodendrocytes were reminiscent of patterns in the MS lesion, leaving us to conclude that Perforin may play an important role in the human disease.

Copyright 2001 Wiley-Liss, Inc.