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Background and Objectives: Diffusion basis spectrum imaging (DBSI) extracts multiple anisotropic and isotropic diffusion tensors, providing greater histopathologic specificity than diffusion tensor imaging (DTI). Persistent black holes (PBH) represent areas of severe tissue damage in multiple sclerosis (MS), and a high PBH burden is associated with worse MS disability. This study evaluated the ability of DBSI and DTI to predict which acute contrast-enhancing lesions (CELs) would persist as T 1 hypointensities (i.e. PBHs) 12 months later. We expected that a higher radial diffusivity (RD), representing demyelination, and higher DBSI-derived isotropic non-restricted fraction, representing edema and increased extracellular space, of the acute CEL would increase the likelihood of future PBH development., Methods: In this prospective cohort study, relapsing MS patients with ≥1 CEL(s) underwent monthly MRI scans for 4 to 6 months until gadolinium resolution. DBSI and DTI metrics were quantified when the CEL was most conspicuous during the monthly scans. To determine whether the CEL became a PBH, a follow-up MRI was performed at least 12 months after the final monthly scan., Results: The cohort included 20 MS participants (median age 33 years; 13 women) with 164 CELs. Of these, 59 (36 %) CELs evolved into PBHs. At Gd-max, DTI RD and AD of all CELs increased, and both metrics were significantly elevated for CELs which became PBHs, as compared to non-black holes (NBHs). DTI RD above 0.74 conferred an odds ratio (OR) of 7.76 (CI 3.77-15.98) for a CEL becoming a PBH (AUC 0.80, CI 0.73-0.87); DTI axial diffusivity (AD) above 1.22 conferred an OR of 7.32 (CI 3.38-15.86) for becoming a PBH (AUC 0.75, CI 0.66-0.83). DBSI RD and AD did not predict PBH development in a multivariable model. At Gd-max, DBSI restricted fraction decreased and DBSI non-restricted fraction increased in all CELs, and both metrics were significantly different for CELs which became PBHs, as compared to NBHs. A CEL with a DBSI non-restricted fraction above 0.45 had an OR of 4.77 (CI 2.35-9.66) for becoming a PBH (AUC 0.74, CI 0.66-0.81); a CEL with a DBSI restricted fraction below 0.07 had an OR of 9.58 (CI 4.59-20.02) for becoming a PBH (AUC 0.80, 0.72-0.87)., Conclusion: Our findings suggest that greater degree of edema/extracellular space in a CEL is a predictor of tissue destruction, as evidenced by PBH evolution., Competing Interests: Declaration of competing interest L. Wooliscroft; A. Salter; G. Adusumilli; V.A. Levasseur; P. Sun; S. Lancia; D.C. Perantie; K. Trinkaus; S.K. Song; and A.H. Cross report no disclosures relevant to the manuscript. R.T. Naismith has consulted for Abata Therapeutics, Alexion Pharmaceuticals, Biogen, Bristol Myers Squibb, Celltrion, Genentech, Genzyme, Janssen, GW Therapeutics, Horizon Therapeutics, Lundbeck, NervGen, TG Therapeutics., (Copyright © 2024. Published by Elsevier B.V.)

Diffusion basis spectrum imaging (DBSI) combines discrete anisotropic diffusion tensors and the spectrum of isotropic diffusion tensors to model the underlying multiple sclerosis (MS) pathologies. We used clinical MS subtypes as a surrogate of underlying pathologies to assess DBSI as a biomarker of pathology in 55 individuals with MS. Restricted isotropic fraction (reflecting cellularity) and fiber fraction (representing apparent axonal density) were the most important DBSI metrics to classify MS using brain white matter lesions. These DBSI metrics outperformed lesion volume. When analyzing the normal-appearing corpus callosum, the most significant DBSI metrics were fiber fraction, radial diffusivity (reflecting myelination), and nonrestricted isotropic fraction (representing edema). This study provides preliminary evidence supporting the ability of DBSI as a potential noninvasive biomarker of MS neuropathology., (© 2019 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals, Inc on behalf of American Neurological Association.)

Background: Improved imaging methods are critical to assess neurodegeneration and remyelination in multiple sclerosis. Chronic hypointensities observed on T1-weighted brain MRI, "persistent black holes," reflect severe focal tissue damage. Present measures consist of determining persistent black holes numbers and volumes, but do not quantitate severity of individual lesions., Objective: Develop a method to differentiate black and gray holes and estimate the severity of individual multiple sclerosis lesions using standard magnetic resonance imaging., Methods: 38 multiple sclerosis patients contributed images. Intensities of lesions on T1-weighted scans were assessed relative to cerebrospinal fluid intensity using commercial software. Magnetization transfer imaging, diffusion tensor imaging and clinical testing were performed to assess associations with T1w intensity-based measures., Results: Intensity-based assessments of T1w hypointensities were reproducible and achieved > 90% concordance with expert rater determinations of "black" and "gray" holes. Intensity ratio values correlated with magnetization transfer ratios (R = 0.473) and diffusion tensor imaging metrics (R values ranging from 0.283 to -0.531) that have been associated with demyelination and axon loss. Intensity ratio values incorporated into T1w hypointensity volumes correlated with clinical measures of cognition., Conclusions: This method of determining the degree of hypointensity within multiple sclerosis lesions can add information to conventional imaging., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Visual dysfunction in MS can be quantified using a variety of tests. Many vision tests have not been formally evaluated among MS patients with existing visual dysfunction., Objective: Evaluate several versions of visual acuity and contrast sensitivity tests, measures of central and peripheral vision, retina structure, electrophysiologic function, and quality of life among MS patients with moderate/severe visual dysfunction., Methods: Cross-sectional study of 46 patients with stable, incompletely recovered optic neuritis. Testing included Snellen eye charts, several Sloan low contrast charts, Pelli Robson (PR) contrast sensitivity charts, optical coherence tomography, visual fields, Farnsworth Munsell 100-hue test, visual evoked potentials (VEP), and visual function quality of life (VFQ-25) testing., Results: 98% of eyes could read two lines of the PR chart, while only 43% read the 2.5% contrast chart. Low contrast tests correlated strongly with each other and with retinal nerve fiber layer (RNFL) thickness, visual fields, and color vision but not with VEPs. For patients with RNFL <75µm, VFQ-25 scores dropped by approximately 2 points for every 1µm decrease in RNFL., Conclusion: Among MS patients with visual impairment due to optic neuritis, PR contrast sensitivity could be utilized as a single chart. Visual quality of life was associated with RNFL thinning below 75µm., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Axon injury/loss, demyelination and inflammation are the primary pathologies in multiple sclerosis lesions. Despite the prevailing notion that axon/neuron loss is the substrate of clinical progression of multiple sclerosis, the roles that these individual pathological processes play in multiple sclerosis progression remain to be defined. An imaging modality capable to effectively detect, differentiate and individually quantify axon injury/loss, demyelination and inflammation, would not only facilitate the understanding of the pathophysiology underlying multiple sclerosis progression, but also the assessment of treatments at the clinical trial and individual patient levels. In this report, the newly developed diffusion basis spectrum imaging was used to discriminate and quantify the underlying pathological components in multiple sclerosis white matter. Through the multiple-tensor modelling of diffusion weighted magnetic resonance imaging signals, diffusion basis spectrum imaging resolves inflammation-associated cellularity and vasogenic oedema in addition to accounting for partial volume effects resulting from cerebrospinal fluid contamination, and crossing fibres. Quantitative histological analysis of autopsied multiple sclerosis spinal cord specimens supported that diffusion basis spectrum imaging-determined cellularity, axon and myelin injury metrics closely correlated with those pathologies identified and quantified by conventional histological staining. We demonstrated in healthy control subjects that diffusion basis spectrum imaging rectified inaccurate assessments of diffusion properties of white matter tracts by diffusion tensor imaging in the presence of cerebrospinal fluid contamination and/or crossing fibres. In multiple sclerosis patients, we report that diffusion basis spectrum imaging quantitatively characterized the distinct pathologies underlying gadolinium-enhanced lesions, persistent black holes, non-enhanced lesions and non-black hole lesions, a task yet to be demonstrated by other neuroimaging approaches. Diffusion basis spectrum imaging-derived radial diffusivity (myelin integrity marker) and non-restricted isotropic diffusion fraction (oedema marker) correlated with magnetization transfer ratio, supporting previous reports that magnetization transfer ratio is sensitive not only to myelin integrity, but also to inflammation-associated oedema. Our results suggested that diffusion basis spectrum imaging-derived quantitative biomarkers are highly consistent with histology findings and hold promise to accurately characterize the heterogeneous white matter pathology in multiple sclerosis patients. Thus, diffusion basis spectrum imaging can potentially serve as a non-invasive outcome measure to assess treatment effects on the specific components of underlying pathology targeted by new multiple sclerosis therapies., (© The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Objective: This study assessed the tissue integrity of major cervical cord tracts by using diffusion tensor imaging (DTI) to determine the relationship with specific clinical functions carried by those tracts., Methods: This was a cross-sectional study of 37 patients with multiple sclerosis or neuromyelitis optica with remote cervical cord disease. Finger vibratory thresholds, 25-foot timed walk (25FTW), 9-hole peg test (9HPT), and Expanded Disability Status Scale were determined. DTI covered cervical regions C1 through C6 with 17 5-mm slices (0.9 × 0.9 mm in-plane resolution). Regions of interest included posterior columns (PCs) and lateral corticospinal tracts (CSTs). Hierarchical linear mixed-effect modeling included covariates of disease subtype (multiple sclerosis vs neuromyelitis optica), disease duration, and sex., Results: Vibration thresholds were associated with radial diffusivity (RD) and fractional anisotropy (FA) in the PCs (both p < 0.01), but not CSTs (RD, p = 0.29; FA, p = 0.14). RD and FA in PCs, and RD in CSTs were related to 9HPT (each p < 0.0001). 25FTW was associated with RD and FA in PCs (p < 0.0001) and RD in CSTs (p = 0.008). Expanded Disability Status Scale was related to RD and FA in PCs and CSTs (p < 0.0001). Moderate/severe impairments in 9HPT (p = 0.006) and 25FTW (p = 0.017) were more likely to show combined moderate/severe tissue injury within both PCs and CSTs by DTI., Conclusions: DTI can serve as an imaging biomarker of spinal cord tissue injury at the tract level. RD and FA demonstrate strong and consistent relationships with clinical outcomes, specific to the clinical modality.

Background: Multiple sclerosis (MS) and neuromyelitis optica (NMO) both affect spinal cord with notable differences in pathology., Objective: Determine the utility of diffusion tensor imaging (DTI) to differentiate the spinal cord lesions of NMO from MS within and outside T2 lesions., Methods: Subjects greater than or equal to 12 months from a clinical episode of transverse myelitis underwent a novel transaxial cervical spinal cord DTI sequence. Ten subjects with NMO, 10 with MS and 10 healthy controls were included., Results: Within T2 affected white matter regions, radial diffusivity was increased in both NMO and MS compared with healthy controls (p<0.001, respectively), and to a greater extent in NMO than MS (p<0.001). Axial diffusivity was decreased in T2 lesions in both NMO and MS compared with controls (p<0.001, p=0.001), but did not differ between the two diseases. Radial diffusivity and fractional anisotropy within white matter regions upstream and downstream of T2 lesions were different from controls in each disease., Conclusions: Higher radial diffusivity within spinal cord white matter tracts derived from diffusion tensor imaging were appreciated in NMO compared with MS, consistent with the known greater tissue destruction seen in NMO. DTI also detected tissue alterations outside T2 lesions and may be a surrogate of anterograde and retrograde degeneration.

Objective: Correlation of diffusion tensor imaging (DTI) with histochemical staining for demyelination and axonal damage in multiple sclerosis (MS) ex vivo human cervical spinal cords., Background: In MS, demyelination, axonal degeneration, and inflammation contribute to disease pathogenesis to variable degrees. Based upon in vivo animal studies with acute injury and histopathologic correlation, we hypothesized that DTI can differentiate between axonal and myelin pathologies within humans., Methods: DTI was performed at 4.7 T on 9 MS and 5 normal control fixed cervical spinal cord blocks following autopsy. Sections were then stained for Luxol fast blue (LFB), Bielschowsky silver, and hematoxylin and eosin (H&E). Regions of interest (ROIs) were graded semi-quantitatively as normal myelination, mild (<50%) demyelination, or moderate-severe (>50%) demyelination. Corresponding axonal counts were manually determined on Bielschowsky silver. ROIs were mapped to co-registered DTI parameter slices. DTI parameters evaluated included standard quantitative assessments of apparent diffusion coefficient (ADC), relative anisotropy (RA), axial diffusivity and radial diffusivity. Statistical correlations were made between histochemical gradings and DTI parameters using linear mixed models., Results: Within ROIs in MS subjects, increased radial diffusivity distinguished worsening severities of demyelination. Relative anisotropy was decreased in the setting of moderate-severe demyelination compared to normal areas and areas of mild demyelination. Radial diffusivity, ADC, and RA became increasingly altered within quartiles of worsening axonal counts. Axial diffusivity did not correlate with axonal density (p=0.091)., Conclusions: Increased radial diffusivity can serve as a surrogate for demyelination. However, radial diffusivity was also altered with axon injury, suggesting that this measure is not pathologically specific within chronic human MS tissue. We propose that radial diffusivity can serve as a marker of overall tissue integrity within chronic MS lesions. This study provides pathologic foundation for on-going in vivo DTI studies in MS., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: B cells are implicated in the pathogenesis of multiple sclerosis. A beneficial effect of B-cell depletion using rituximab has been shown, but the complete mechanism of action for this drug is unclear., Objective: To determine the relationship between T and B cells and changes in cerebrospinal fluid (CSF) chemokine levels with rituximab, a monoclonal antibody that targets CD20., Design: Phase 2 trial of rituximab as an add-on therapy., Setting: The John L. Trotter Multiple Sclerosis Center, Washington University. Participants and Intervention Thirty subjects who had relapsing-remitting multiple sclerosis with clinical and magnetic resonance imaging activity despite treatment with an immunomodulatory drug received 4 weekly doses of rituximab (375 mg/m(2))., Main Outcome Measures: Lumbar puncture was performed before and after rituximab infusions in 26 subjects. Levels of B and T lymphocytes in the CSF were enumerated by flow cytometry, and chemoattractant levels were measured by enzyme-linked immunosorbent assay., Results: After rituximab administration, CSF B-cell levels were decreased or undetectable in all subjects, and CSF T-cell levels were reduced in 21 subjects (81%). The mean reduction in CSF cellularity was 95% for B cells and 50% for T cells. After rituximab infusion, CSF CXCL13 and CCL19 levels decreased (P = .002 and P = .03, respectively). The proportional decline in CSF T-cell levels correlated with the proportional decrease in CXCL13 levels (r = 0.45; P = .03), suggesting a possible relationship. The CSF IgG index, IgG concentration, and oligoclonal band number were unchanged following treatment., Conclusions: In subjects with multiple sclerosis, B cells are critical for T-cell trafficking into the central nervous system and may alter the process by influencing chemokine production within the central nervous system.

Background: African Americans (AAs) experience greater disability from multiple sclerosis (MS) compared with Caucasian Americans (CAs). Interethnic immunologic differences in MS and their relationship to disease-related disability have not been described., Objective: To compare measures of CSF humoral immunity between AAs and CAs with MS., Methods: Using a case-control design, all AA MS patients with CSF immune studies at the Washington University MS center were compared with randomly selected CAs with MS. Two CA controls were selected for every AA case. Immunoglobulin G (IgG) index and synthesis rates, oligoclonal band positivity, white blood cell count, and CSF protein were compared between groups. Survival analysis was conducted to compare times to ambulatory assistance., Results: Sixty-six AA cases and 132 CA controls were identified. Measures of CSF humoral activity were all higher in the AA group. The mean IgG index of AAs was 1.35 (SD 0.62), and that of CAs was 1.05 (SD 0.55), for a mean difference of 0.30 (p = 0.001). The median IgG synthesis rate was also higher among AAs (13.55 vs 8.20 mg/day), for a median difference of 5.35 mg/day (p = 0.010). Survival analysis confirmed previous reports of earlier ambulatory assistance requirement among AAs. Despite differences in both humoral immune response and times to ambulatory assistance, Cox proportional hazards modeling did not show IgG index as predictive of earlier ambulatory assistance., Conclusions: The CSF humoral immune response is more active among African Americans (AAs) than among Caucasian Americans (CAs) with multiple sclerosis. AAs also progress to ambulatory assistance earlier than CAs, but high immunoglobulin G index does not predict earlier progression to the disability endpoint.

Elevated CSF free kappa light chains (FKLCs) may predict disability in multiple sclerosis (MS). We reviewed records of 57 patients with MS with 15-year median follow-up for correlations of disability and CSF FKLCs. Levels > or = 1.53 microg/mL predicted progression to need for ambulatory assistance during follow-up (specificity 87.5%, positive predictive value 88.9%) or within 10 years (specificity 78.6%, positive predictive value 66.7%).

Objectives: To examine if depression in multiple sclerosis (MS) can be accurately recognized using the Yale Single Question (YSQ) screen as compared with the Beck Depression Inventory (BDI), a 21-item self-report rating scale for depression. In addition, we sought to assess the sensitivity, specificity the positive predictive value (PPV) and the negative predictive value (NPV) of the YSQ., Background: Depression associated with MS is a major contributor to morbidity. Screening for depression in patients with MS currently includes the BDI, which measures characteristic attitudes and symptoms of depression. However, in a busy outpatient clinic, the BDI might not be the most appropriate instrument, particularly if depression screening can be assessed accurately using simpler techniques that are easy to administer and consume less time. We compared the accuracy of the YSQ screen response against the BDI to screen for depression in MS patients, in an outpatient setting., Methods: This is a comparative outcome study of two 'instruments' used for screening depression in MS patients in an academic outpatient setting. All patients were initially screened for depression by asking patients the YSQ--'Do you frequently feel sad or depressed?', followed by BDI administration. Depression was defined as a score of > or = 13 on the BDI. One hundred and twenty successive patients who presented to the MS clinic at Washington University School of Medicine and met the criteria for diagnosis of MS were screened for depression. All patients diagnosed as having MS, regardless of type, were included in the study., Results: Of the 120 patients studied, a total of 49 of 120 were clinically depressed as defined by a BDI cut-off of > or = 13; 71 of 120 were not. The sensitivity of the YSQ was 32 of 49 = 65.3% with a 95% confidence interval (0.50, 0.78), specificity was 62 of 71 = 87.3% (0.77, 0.94), PPV was 32 of 41 = 78.0% (0.62, 0.89) and NPV was 62 of 79 = 78.5% (0.68, 0.87). Of the 49 patients depressed by BDI criteria, 17 responded 'no' to the YSQ, yielding a false-negative rate of 34.7% (0.22, 0.50). The Wilcoxon-Mann-Whitney test for difference in age among those on antidepressants compared with those who were not showed no statistical difference (P = 0.35). For patients on antidepressants, the mean BDI score was 16.0+/-8.9 (mean+/-SD) and 9.5+/-8.7 for those not on antidepressants. Differences in BDI scores among patients on antidepressants versus those who were not were statistically significant (P < 0.0001). Patients on antidepressants had significantly higher BDI scores., Conclusions: Our results show that the YSQ cannot replace the BDI as a screening instrument for depression in MS. The YSQ could not identify 34.7% of patients who were depressed by BDI criteria. However, as reported in a published study, BDI missed 30% of cases with early depression in MS when a cut-off of > or = 13 was used. The YSQ appears to be specific in ruling out depression when a patient is not depressed. MS is a chronic disease and since prevalence of depression varies, it is important to screen patients repeatedly over time so as not to miss the diagnosis. That BDI scores were higher among those taking antidepressants underscores the fact that this subset of patients need to be on medication, but the higher scores could also represent a sampling error since the duration of antidepressant use was not studied.

Diffusion basis spectrum imaging (DBSI) models diffusion-weighted magnetic resonance imaging (MRI) signals as a combination of discrete anisotropic diffusion tensors and a spectrum of isotropic diffusion tensors. Here, we report the histopathological correlates of DBSI in the biopsied brain tissue of a patient with an inflammatory demyelinating lesion typical of multiple sclerosis (MS). Increased radial diffusivity (marker of demyelination), decreased fiber fraction (apparent axonal density), elevated nonrestricted isotropic fraction (marker of vasogenic edema), but unchanged axial diffusivity (marker of integrity of residual axons) seen in the lesion appeared consistent with histopathological findings of inflammatory demyelination with relative axonal sparing. Our report supports the application of DBSI as a biomarker in human studies of MS. [ABSTRACT FROM AUTHOR]

Axon injury/loss, demyelination and inflammation are the primary pathologies in multiple sclerosis lesions. Despite the prevailing notion that axon/neuron loss is the substrate of clinical progression of multiple sclerosis, the roles that these individual pathological processes play in multiple sclerosis progression remain to be defined. An imaging modality capable to effectively detect, differentiate and individually quantify axon injury/loss, demyelination and inflammation, would not only facilitate the understanding of the pathophysiology underlying multiple sclerosis progression, but also the assessment of treatments at the clinical trial and individual patient levels. In this report, the newly developed diffusion basis spectrum imaging was used to discriminate and quantify the underlying pathological components in multiple sclerosis white matter. Through the multiple-tensor modelling of diffusion weighted magnetic resonance imaging signals, diffusion basis spectrum imaging resolves inflammation-associated cellularity and vasogenic oedema in addition to accounting for partial volume effects resulting from cerebrospinal fluid contamination, and crossing fibres. Quantitative histological analysis of autopsied multiple sclerosis spinal cord specimens supported that diffusion basis spectrum imaging-determined cellularity, axon and myelin injury metrics closely correlated with those pathologies identified and quantified by conventional histological staining. We demonstrated in healthy control subjects that diffusion basis spectrum imaging rectified inaccurate assessments of diffusion properties of white matter tracts by diffusion tensor imaging in the presence of cerebrospinal fluid contamination and/or crossing fibres. In multiple sclerosis patients, we report that diffusion basis spectrum imaging quantitatively characterized the distinct pathologies underlying gadolinium-enhanced lesions, persistent black holes, non-enhanced lesions and non-black hole lesions, a task yet to be demonstrated by other neuroimaging approaches. Diffusion basis spectrum imaging-derived radial diffusivity (myelin integrity marker) and non-restricted isotropic diffusion fraction (oedema marker) correlated with magnetization transfer ratio, supporting previous reports that magnetization transfer ratio is sensitive not only to myelin integrity, but also to inflammation-associated oedema. Our results suggested that diffusion basis spectrum imaging-derived quantitative biomarkers are highly consistent with histology findings and hold promise to accurately characterize the heterogeneous white matter pathology in multiple sclerosis patients. Thus, diffusion basis spectrum imaging can potentially serve as a non-invasive outcome measure to assess treatment effects on the specific components of underlying pathology targeted by new multiple sclerosis therapies. [ABSTRACT FROM AUTHOR]

Clinicopathological paradox has hampered significantly the effective assessment of the efficacy of therapeutic intervention for multiple sclerosis. Neuroimaging biomarkers of tissue injury could guide more effective treatment by accurately reflecting the underlying subclinical pathologies. Diffusion tensor imaging-derived directional diffusivity and anisotropy indices have been applied to characterize white matter disorders. However, these biomarkers are sometimes confounded by the complex pathologies seen in multiple sclerosis and its animal models. Recently, a novel technique of diffusion basis spectrum imaging has been developed to quantitatively assess axonal injury, demyelination and inflammation in a mouse model of inflammatory demyelination. Lenaldekar, which inhibits T-cell expansion in a non-cytolytic manner, has been shown to suppress relapses and preserve white matter integrity in mice with experimental autoimmune encephalomyelitis. In this study, relapsing-remitting experimental autoimmune encephalomyelitis was induced through active immunization of SJL/J mice with a myelin proteolipid protein peptide. The therapeutic efficacy of Lenaldekar treatment was evaluated via daily clinical score, cross-sectional ex vivo diffusion basis spectrum imaging examination and histological analysis. Lenaldekar greatly reduced relapse severity and protected white matter integrity in these experimental autoimmune encephalomyelitis mice. Diffusion basis spectrum imaging-derived axial diffusivity, radial diffusivity and restricted diffusion tensor fraction accurately reflected axonal injury, myelin integrity and inflammation-associated cellularity change, respectively. These results support the potential use of diffusion basis spectrum imaging as an effective outcome measure for preclinical drug evaluation. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Fingolimod (FTY720) is an orally available sphingosine-1-phosphate (S1P) receptor modulator reducing relapse frequency in patients with relapsing-remitting multiple sclerosis (RRMS). In addition to immunosuppression, neuronal protection by FTY720 has also been suggested, but remains controversial. Axial and radial diffusivities derived from in vivo diffusion tensor imaging (DTI) were employed as noninvasive biomarkers of axonal injury and demyelination to assess axonal protection by FTY720 in experimental autoimmune encephalomyelitis (EAE) mice. EAE was induced through active immunization of C57BL/6 mice using myelin oligodendrocyte glycoprotein peptide 35-55 (MOG35-55). We evaluated both the prophylactic and therapeutic treatment effect of FTY720 at doses of 3 and 10 mg/kg on EAE mice by daily clinical scoring and end-point in vivo DTI. Prophylactic administration of FTY720 suppressed the disease onset and prevented axon and myelin damage when compared with EAE mice without treatment. Therapeutic treatment by FTY720 did not prevent EAE onset, but reduced disease severity, improving axial and radial diffusivity towards the control values without statistical significance. Consistent with previous findings, in vivo DTI-derived axial and radial diffusivity correlated with clinical scores in EAE mice. The results support the use of in vivo DTI as an effective outcome measure for preclinical drug development. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article discusses the use of diffusion tensor imaging (DTI) to differentiate the spinal cord lesions caused by neuromyelitis optica (NMO) with multiple sclerosis (MS). It states that DTI shows that radial diffusivity is much greater with NMO than with MS. It says that the results shows much greater tissue destruction caused by NMO than caused by MS.

Optic neuritis is frequently the first symptom of multiple sclerosis (MS), an inflammatory demyelinating neurodegenerative disease. Impaired axonal transport has been considered as an early event of neurodegenerative diseases. However, few studies have assessed the integrity of axonal transport in MS or its animal models. We hypothesize that axonal transport impairment occurs at the onset of optic neuritis in experimental autoimmune encephalomyelitis (EAE) mice. In this study, we employed manganese-enhanced MRI (MEMRI) to assess axonal transport in optic nerves in EAE mice at the onset of optic neuritis. Axonal transport was assessed as (a) optic nerve Mn 2 + accumulation rate (in % signal change/h) by measuring the rate of increased total optic nerve signal enhancement, and (b) Mn 2 + transport rate (in mm/h) by measuring the rate of change in optic nerve length enhanced by Mn 2 + . Compared to sham-treated healthy mice, Mn 2 + accumulation rate was significantly decreased by 19% and 38% for EAE mice with moderate and severe optic neuritis, respectively. The axonal transport rate of Mn 2 + was significantly decreased by 43% and 65% for EAE mice with moderate and severe optic neuritis, respectively. The degree of axonal transport deficit correlated with the extent of impaired visual function and diminished microtubule-associated tubulins, as well as the severity of inflammation, demyelination, and axonal injury at the onset of optic neuritis. [ABSTRACT FROM AUTHOR]

Abstract: Optic neuritis is a frequent and early symptom of multiple sclerosis (MS). Conventional magnetic resonance (MR) techniques provide means to assess multiple MS-related pathologies, including axonal injury, demyelination, and inflammation. A method to directly and non-invasively probe white-matter function could further elucidate the interplay of underlying pathologies and functional impairments. Previously, we demonstrated a significant 27% activation-associated decrease in the apparent diffusion coefficient of water perpendicular to the axonal fibers (ADC⊥) in normal C57BL/6 mouse optic nerve with visual stimulation using diffusion fMRI. Here we apply this approach to explore the relationship between visual acuity, optic nerve pathology, and diffusion fMRI in the experimental autoimmune encephalomyelitis (EAE) mouse model of optic neuritis. Visual stimulation produced a significant 25% (vs. baseline) ADC⊥ decrease in sham EAE optic nerves, while only a 7% (vs. baseline) ADC⊥ decrease was seen in EAE mice with acute optic neuritis. The reduced activation-associated ADC⊥ response correlated with post-MRI immunohistochemistry determined pathologies (including inflammation, demyelination, and axonal injury). The negative correlation between activation-associated ADC⊥ response and visual acuity was also found when pooling EAE-affected and sham groups under our experimental criteria. Results suggest that reduction in diffusion fMRI directly reflects impaired axonal-activation in EAE mice with optic neuritis. Diffusion fMRI holds promise for directly gauging in vivo white-matter dysfunction or therapeutic responses in MS patients. [Copyright &y& Elsevier]