MS Abstracts 01d-2g4

Purpose
To quantify, with three-dimensional Proton Magnetic Resonance (MR) Spectroscopy, metabolic characteristics of Normal-Appearing White Matter and nonenhancing lesions in patients with Relapsing/Remitting Multiple Sclerosis (MS).

Materials And Methods
Institutional review board approval and informed patient consent were obtained.

Nine patients with Relapsing/Remitting MS (six women, three men) and nine age-matched control subjects (seven women, two men) were studied with T₁- and T₂-weighted MR imaging and three-dimensional Proton MR Spectroscopy at spatial resolution less than a cubic centimeter.

Absolute N-AcetylAspartate (NAA), Creatine (Cr), and Choline (Cho) levels were obtained from 171 Voxels: 66 from lesions on T₂-weighted MR images (43 HypoIntense and 23 IsoIntense on T₂-weighted MR images), 31 from Normal-Appearing White Matter, and 74 from analogous normal White Matter regions on images in control subjects.

Results
Mean NAA level in HypoIntense lesions (5.30 mmol/L +/- 2.27 [standard deviation]) was significantly lower (P < /= .05) than that in:
1. IsoIntense lesions (7.82 mmol/L +/- 2.28)
2. Normal-Appearing White Matter (7.37 mmol/L +/- 1.71)
3. Normal White Matter in control subjects (8.89 mmol/L +/- 1.54).

Cho (1.79 mmol/L +/- 0.65) and Cr (5.64 mmol/L +/- 1.50) levels in IsoIntense lesions were indistinguishable from those in Normal-Appearing White Matter (1.74 mmol/L +/- 0.46 and 4.99 mmol/L +/- 0.97, respectively).

But, were significantly higher (Cho, 20%; Cr, 24%) than those in Normal White Matter in control subjects (1.44 mmol/L +/- 0.40 and 4.30 mmol/L +/- 1.32, respectively).

NAA, Cho, and Cr levels in Normal-Appearing White Matter were significantly different than those in normal White Matter in control subjects (NAA, 20% lower; Cho, 14% higher; and Cr, 17% higher).

Conclusion
Abnormal metabolic activity persists in all MS tissue types.

Increased Cr and Cho levels suggest:
1. Ongoing Gliosis and attempted ReMyelination
• In IsoIntense lesions on T₂-weighted MR images
2. Membrane turnover (De- and ReMyelination), in addition to
• Increased cellularity (Gliosis, Inflammation) in Normal-Appearing White Matter

Evidence for the effectiveness of ImmunoSuppressive agents in MS is scanty. There are few good quality trials; most have methodological limitations, such as a small sample size and short duration.

Moreover, there is no consistency in treatment regimes, patient groups or outcome measures and the clinical benefits remain unclear.

Although Azathioprine appears to reduce the relapse rate in MS patients, its effect on disability progression has not been demonstrated. Methotrexate may alter the course of disease favorably in patients with Progressive MS, but the evidence is again sparse.

We assessed Decision-Making Capacity and Emotional Reactivity in 20 patients with Multiple Sclerosis (MS) and in 16 healthy subjects using the Gambling Task (GT), a model of real-life decision making, and the Skin Conductance Response (SCR).

Demographic, Neurological, Affective, and Cognitive parameters were analyzed in MS patients for their effect on decision-making performance.

MS patients persisted longer (slope, -3.6%) than the comparison group (slope, -6.4%) in making disadvantageous choices as the GT progressed (p < 0.001), suggesting significant slower learning in MS.

Patients with higher Expanded Disability Status Scale scores (EDSS >2.0) showed a different pattern of Impairment in the learning process compared with patients with lower Functional Impairment (EDSS < /=2.0).

This slower learning was associated with Impaired Emotional Reactivity (anticipatory SCR 3.9 vs 6.1 microSiemens [μS] for patients vs the comparison group, p < 0.0001; post-choice SCR 3.9 vs 6.2μS, p < 0.0001), but not with Executive Dysfunction.

Impaired Emotional dimensions of behavior (assessed using the DysExecutive Questionnaire, p < 0.002) also correlated with slower learning.

Given the considerable consequences that Impaired Decision Making can have on daily life, we suggest that this factor may contribute to handicap and altered quality of life secondary to MS and is dependent on Emotional experience.

Multiple Sclerosis (MS) is an Inflammatory DeMyelinating Disorder of the CNS. A recent study identified 4 patterns of DeMyelination in active MS lesions.

The characteristics of Pattern II lesions suggested a primary inflammatory mechanism of Myelin injury, while Pattern III lesions showed features consistent with dying-back OligodendroGliopathy.

The recruitment, differentiation, and activation of MonoNuclear Phagocytes are dependent on the expression of Chemokine Receptors.

Using ImmunoHistoChemistry we quantified cellular expression of CCR1 and CCR5 in Pattern II (n = 21) and Pattern III (n = 17) lesion areas of differing DeMyelinating activity.

Infiltrating Monocytes in both lesion patterns co-expressed CCR1 and CCR5, suggesting conserved mechanisms of Monocyte recruitment into the CNS.

In Pattern II lesions, the number of cells expressing CCR1 significantly decreased while CCR5 increased in late active compared with early active DeMyelinating regions.

In striking contrast, numbers of cells expressing CCR1 and CCR5 were equal in all regions of Pattern III lesions.

As Hypoxia-like mechanisms may play a role in Pattern III lesions, we extended these studies to White Matter Infarcts (n = 7) in which the expression of CCR1 better resembled Pattern III than Pattern II lesions.

As judged by MonoNuclear Phagocytic Chemokine Receptor expression, there appear to be distinct tissue environments in Pattern II and III MS lesions.

Background
IntraVenous ImmunoGlobulin (IVIg) has been reported to reduce disease activity in patients with Relapsing/Remitting Multiple Sclerosis.

We assessed the effect of IVIg treatment in patients after the first Neurological event suggestive of DeMyelinative Disease and evaluated the occurrence of a second attack and dissemination in time demonstrated by Brain Magnetic Resonance Imaging within the first year from onset.

Methods
We conducted a randomized, placebo-controlled, double-blind study in 91 eligible patients enrolled within the first 6 weeks of Neurological symptoms.

Patients were randomly assigned to receive IVIg treatment (2-g/kg loading dose) or placebo, with boosters (0.4 g/kg) given once every 6 weeks for 1 year.

Neurological and clinical assessments were done every 3 months, and Brain Magnetic Resonance Imaging was performed at baseline and the end of the study.

Results
The cumulative probability of developing Clinically Definite Multiple Sclerosis was significantly lower in the IVIg treatment group compared with the placebo group (rate ratio, 0.36 [95% confidence interval, 0.15-0.88]; P = .03).

Patients in the IVIg treatment group had a significant reduction in the volume and number of T₂-weighted lesions and in the volume of Gadolinium-enhancing lesions as compared with the placebo group (P = .01, P = .01, and P = .03, respectively).

Treatment was well tolerated, compliance was high, and incidence of adverse effects did not differ significantly between groups.

Conclusions
IntraVenous ImmunoGlobulin treatment for the first year from onset of the first Neurological event suggestive of DeMyelinative Disease significantly lowers the incidence of a second attack and reduces disease activity as measured by Brain Magnetic Resonance Imaging.

Major Histocompatibility Complex (MHC) molecules are rare in the healthy Brain tissue, but are heavily expressed on Microglial Cells after Inflammatory or NeuroDegenerative processes.

We studied the conditions leading to the induction of MHC Class II molecules in Microglia by using explant cultures of neonatal rat Hippocampus, a model of interacting Neuronal Networks.

Interferon-gamma (IFN-γ)-dependent MHC Class II inducibility in Microglia Cells was very low, but strongly increased in the Hippocampal slices after the blockade of Neuronal activity by NeuroToxins [Tetrodotoxin (TTX), omega-Conotoxin] or Glutamate Antagonists.

None of these agents acted directly on isolated Microglia Cells. We found that NeuroTrophins modulate Microglial MHC Class II expression.

MHC Class II inducibility was enhanced by neutralization of NeuroTrophins produced locally within the cultured tissues and was inhibited by the addition of Nerve Growth Factor (NGF), Brain-Derived Neurotrophic Factor (BDNF), or NeuroTrophin-3 (NT3).

NGF and, to a lower extent, NT3 acted directly on isolated Microglia via the p75 NeuroTrophin Receptor and inhibited MHC Class II inducibility as shown by blockade of the p75 NeuroTrophin Receptor with AntiBodies.

Our data suggest that NeuroTrophins secreted by electrically active Neurons control the Antigen-Presenting potential of Microglia Cells, and indicate that this effect is mediated partly via the p75 NeuroTrophin Receptor.

Neonatal Microglial Cells respond to GM-CSF and M-CSF by acquiring different morphologies and phenotypes.

To investigate the extent and consequences of this process, a global Gene expression analysis was performed, with significant changes in transcript levels confirmed by biochemical analyses.

Primary murine Microglial Cells underwent substantial expression reprogramming after treatment with GM-CSF or M-CSF with many differentially expressed transcripts important in Innate and Adaptive Immunity.

In particular, many Gene products involved in Ag presentation were induced by GM-CSF, but not M-CSF, thus potentially priming relatively quiescent Microglia Cells for Ag presentation.

This function of GM-CSF is distinct from its primary function in cell proliferation and survival.

Objective
The authors compared two methods, the Marcus Gunn test and the alternating light test, for detecting a Relative Afferent Pupillary Defect.

Design, Participants, & Intervention
A randomized, prospective clinical trial, fourteen patients with Unilateral Optic Neuropathy. The Marcus Gunn and alternating light tests were performed on each patient.

Main Outcome Measures
The results of the Marcus Gunn and altemating light tests for detecting a Relative Afferent Pupillary Defect on the affected side.

Results
The Marcus Gunn test was able to identify the affected Eye in only 8 of 14 patients, whereas the alternating light test correctly identified the affected Eye in 13 of 14 patients.

Results of the Marcus Gunn test were indeterminate in 4 of 14 patients and were incorrect in 2 of 14 patients. Results of the alternating light test were indeterminate in one patient and never incorrectly identified the affected Eye.

Conclusion
The alternating light test is superior to the Marcus Gunn test for detecting Relative Afferent Pupillary Defects.

Objectives
To study the change in Disability over 10 years in individual patients constituting the 1991 Olmsted County, MN, Multiple Sclerosis (MS) prevalence cohort.

Methods
The authors reassessed this 1991 cohort in 2001. The authors determined the Expanded Disability Status Scale scores (EDSS) for each patient still alive, and within the year prior to death for those who died.

The authors analyzed determinants of potential prognostic significance on change in disability.

Results
Follow-up information was available for 161 of 162 patients in the 1991 cohort. Only 15% had received ImmunoModulatory therapy.

The mean change in EDSS for the entire cohort over 10 years was 1 point and 20% worsened by >or=2 points.

For patients with EDSS < 3 in 1991 (n = 66), 83% were ambulatory without a cane 10 years later.

For patients with EDSS of 3 through 5 in 1991 (n = 33), 51% required a cane to ambulate (48%) or worse (3%). For patients with EDSS 6 to 7 in 1991 (n = 39), 51% required a wheelchair or worse in 2001.

Gait Impairment at onset, Progressive disease, or longer duration of disease were associated with more worsening of disability (p < 0.002). The 10-year survival was decreased compared with the Minnesota white population for both men and women.

Conclusions
Although survival was reduced and 30% of patients progressed to needing a cane or wheelchair or worse over the 10-year follow-up period, most remained stable or minimally progressed.

Patients within the EDSS 3.0 through 5.0 range are at moderate risk of developing important Gait limitations over the 10-year period. The authors did not identify factors strongly predictive of worsening Disability in this study.

Background
Axonal damage has been observed in Normal-Appearing White Matter (NAWM) for patients with Multiple Sclerosis (MS).

Objectives
To investigate changes in Brain metabolite ratios in a region of Normal-Appearing Corpus Callosum (CC) for patients with MS and to test its relationship to changes in other regions of NAWM.

Design And Methods
Data were collected from 24 patients with MS and 15 control subjects. Two-dimensional Proton Magnetic Resonance Spectroscopic Imaging was performed centered at the CC.

Regions of interest from Normal-Appearing CC were manually segmented using anatomical images. The NAWM outside the CC region was segmented based on the signal intensity in T₁- and T₂-weighted images.

Results
The N-AcetylAspartate-Creatine-PhosphoCreatine Ratio was lower in both regions for patients with Secondary/Progressive MS compared with the controls.

The N-AcetylAspartate-Creatine-PhosphoCreatine was lower only in the Normal-Appearing CC region for patients with Relapsing/Remitting MS (P< .001) compared with the controls.

The ratio of Choline-containing compound compared with the Creatine-PhosphoCreatine Ratio was also lower in the region of Normal-Appearing CC for patients with Relapsing/Remitting MS (P =.003) compared with the controls.

There was a correlation between the N-AcetylAspartate-Creatine-PhosphoCreatine Ratio in the Normal-Appearing CC and T₂ lesions (r = -0.53, P =.01) for all patients.

Conclusions
The CC was a more sensitive location for depicting Axonal injury than other regions of NAWM.

A correlation between the reduction of the N-AcetylAspartate-Creatine-PhosphoCreatine Ratio in the Normal-Appearing CC and the T₂ lesions may suggest that transection of Axons in lesions may cause distant Axonal Damage and/or dysfunction that are expressed and more sensitively detectable in the CC.

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 Gray 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, Forceps Minor and Forceps Major (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 Forceps Major and Forceps Minor, 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.

Lesions in the Corpus Callosum in Multiple Sclerosis (MS) include those that are HyperIntense on T₂-weighted images, which can be either focal (isolated) or connected.

But, there is evidence that the Corpus Callosum, similar to other White Matter regions, contains Normal-Appearing White Matter (NAWM).

Which is abnormal based on quantitative MR methodologies. In this pilot study, Diffusion Tensor based measures were determined in Corpus Callosum from 10 patients with MS and 12 age and gender matched controls.

T₂-HyperIntense lesions were carefully segmented out from Normal-Appearing Corpus Collosium to minimize contamination of the NAWM fraction with these lesions.

The orientationally averaged Diffusion Coefficient was increased and the Fractional Anisotropy reduced in the NAWM fraction of the MS patients.

These results confirm prior studies which suggest that pathology in the NAWM occurs independent of focal MS lesions, and are not likely the result of sample contamination through or across slices.

This injury to the NAWM may be the result of focal, microscopic T₂-invisible lesions and/or secondary degeneration related to distant lesions whose related fibers cross the Corpus Callosum.