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Background: Several studies have demonstrated that early childhood and adolescent obesity are risk factors for multiple sclerosis (MS) susceptibility. Obesity is thought to share inflammatory components with MS through overproduction of pro-inflammatory adipokines (e.g., leptin) and reduction of anti-inflammatory adipokines (e.g, adiponectin). Recently, drug repurposing (i.e. identifying new indications for existing drugs) has garnered significant attention. The US Food and Drug Administration Adverse Event Reporting System (FAERS) database serves not only as a resource for mining adverse drug reactions and safety signals but also for identifying inverse associations and potential medication repurposing opportunities. Objective: We aimed to explore the association between weight-loss-inducing drugs and MS using real-world reports from the FAERS database. Design: Secondary analysis of existing data from the FAERS database. Methods: We conducted a disproportionality analysis using the FAERS database between the fourth quarter of 2003 and the second quarter of 2023 to explore associations between MS and weight loss-inducing drugs. Disproportionality was quantified using the reporting odds ratio (ROR). An inverse association was defined when the upper limit of the 95% confidence interval for ROR was

Abstract Objective Neurodegenerative conditions often manifest radiologically with the appearance of premature aging. Multiple sclerosis (MS) biomarkers related to lesion burden are well developed, but measures of neurodegeneration are less well‐developed. The appearance of premature aging quantified by machine learning applied to structural MRI assesses neurodegenerative pathology. We assess the explanatory and predictive power of “brain age” analysis on disability in MS using a large, real‐world dataset. Methods Brain age analysis is predicated on the over‐estimation of predicted brain age in patients with more advanced pathology. We compared the performance of three brain age algorithms in a large, longitudinal dataset (>13,000 imaging sessions from >6,000 individual MS patients). Effects of MS, MS disease course, disability, lesion burden, and DMT efficacy were assessed using linear mixed effects models. Results MS was associated with advanced predicted brain age cross‐sectionally and accelerated brain aging longitudinally in all techniques. While MS disease course (relapsing vs. progressive) did contribute to advanced brain age, disability was the primary correlate of advanced brain age. We found that advanced brain age at study enrollment predicted more disability accumulation longitudinally. Lastly, a more youthful appearing brain (predicted brain age less than actual age) was associated with decreased disability. Interpretation Brain age is a technically tractable and clinically relevant biomarker of disease pathology that correlates with and predicts increasing disability in MS. Advanced brain age predicts future disability accumulation.

Abstract Objective Multiple sclerosis (MS) is a common demyelinating central nervous system disease. MRI methods that can quantify myelin loss are needed for trials of putative remyelinating agents. Quantitative magnetization transfer MRI introduced the macromolecule proton fraction (MPF), which correlates with myelin concentration. We developed an alternative approach, Simultaneous‐Multi‐Angular‐Relaxometry‐of‐Tissue (SMART) MRI, to generate MPF. Our objective was to test SMART‐derived MPF metric as a potential imaging biomarker of demyelination. Methods Twenty healthy control (HC), 11 relapsing–remitting MS (RRMS), 22 progressive MS (PMS), and one subject with a biopsied tumefactive demyelinating lesion were scanned at 3T using SMART MRI. SMART‐derived MPF metric was determined in normal‐appearing cortical gray matter (NAGM), normal‐appearing subcortical white matter (NAWM), and demyelinating lesions. MPF metric was evaluated for correlations with physical and cognitive test scores. Comparisons were made between HC and MS and between MS subtypes. Furthermore, correlations were determined between MPF and neuropathology in the biopsied person. Results SMART‐derived MPF in NAGM and NAWM were lower in MS than HC (p

Summary: Background: Neurofilament light chain (NfL), a neuronal cytoskeletal protein that is released upon neuroaxonal injury, is associated with multiple sclerosis (MS) relapsing activity and has demonstrated some prognostic ability for future relapse-related disease progression, yet its value in assessing non-relapsing disease progression remains unclear. Methods: We examined baseline and longitudinal blood NfL levels in 1421 persons with relapsing MS (RMS) and 596 persons with primary progressive MS (PPMS) from the pivotal ocrelizumab MS trials. NfL treatment-response and risk for disease worsening (including disability progression into the open-label extension period and slowly expanding lesions [SELs] on brain MRI) at baseline and following treatment with ocrelizumab were evaluated using time-to-event analysis and linear regression models. Findings: In persons from the RMS control arms without acute disease activity and in the entire PPMS control arm, higher baseline NfL was prognostic for greater whole brain and thalamic atrophy, greater volume expansion of SELs, and clinical progression. Ocrelizumab reduced NfL levels vs. controls in persons with RMS and those with PPMS, and abrogated the prognostic value of baseline NfL on disability progression. Following effective suppression of relapse activity by ocrelizumab, NfL levels at weeks 24 and 48 were significantly associated with long-term risk for disability progression, including up to 9 years of observation in RMS and PPMS. Interpretation: Highly elevated NfL from acute MS disease activity may mask a more subtle NfL abnormality that reflects underlying non-relapsing progressive biology. Ocrelizumab significantly reduced NfL levels, consistent with its effects on acute disease activity and disability progression. Persistently elevated NfL levels, observed in a subgroup of persons under ocrelizumab treatment, demonstrate potential clinical utility as a predictive biomarker of increased risk for clinical progression. Suppression of relapsing biology with high-efficacy immunotherapy provides a window into the relationship between NfL levels and future non-relapsing progression. Funding: F. Hoffmann-La Roche Ltd.

Abstract Objective To enable use of clinical magnetic resonance images (MRIs) to quantify abnormalities in normal appearing (NA) white matter (WM) and gray matter (GM) in multiple sclerosis (MS) and to determine associations with MS‐related disability. Identification of these abnormalities heretofore has required specialized scans not routinely available in clinical practice. Methods We developed an analytic technique which normalizes image intensities based on an intensity atlas for quantification of WM and GM abnormalities in standardized MRIs obtained with clinical sequences. Gaussian mixture modeling is applied to summarize image intensity distributions from T1‐weighted and 3D‐FLAIR (T2‐weighted) images from 5010 participants enrolled in a multinational database of MS patients which collected imaging, neuroperformance and disability measures. Results Intensity distribution metrics distinguished MS patients from control participants based on normalized non‐lesional signal differences. This analysis revealed non‐lesional differences between relapsing MS versus progressive MS subtypes. Further, the correlation between our non‐lesional measures and disability was approximately three times greater than that between total lesion volume and disability, measured using the patient derived disease steps. Multivariate modeling revealed that measures of extra‐lesional tissue integrity and atrophy contribute uniquely, and approximately equally, to the prediction of MS‐related disability. Interpretation These results support the notion that non‐lesional abnormalities correlate more strongly with MS‐related disability than lesion burden and provide new insight into the basis of abnormalities in NA WM. Non‐lesional abnormalities distinguish relapsing from progressive MS but do not distinguish between progressive subtypes suggesting a common progressive pathophysiology. Image intensity parameters and existing biomarkers each independently correlate with MS‐related disability.

ObjectiveThis study aims to confirm the prognostic value of baseline serum neurofilament light chain (sNfL) for on-study disease activity and worsening in patients with relapsing MS (RMS).BackgroundPrevious post-hoc studies suggested that sNfL could be a prognostic biomarker in RMS. In the phase 3 ASCLEPIOS I/II trials in which ofatumumab demonstrated better efficacy outcomes than teriflunomide, treatment with ofatumumab also led to significantly reduced sNfL levels compared to teriflunomide treatment.Design/MethodsIn this study, we report protocol-planned analyses from the pooled ASCLEPIOS I/II trials (N=1882). Per protocol, patients were stratified by median baseline sNfL levels (9.3 pg/ml) into high (>median) and low (≤median) categories to prognosticate: annualized rate of new/enlarging T2 (neT2) lesions in year 1 and 2, annualized relapse rate, annual percentage change in whole brain (WB) and regional brain volume [thalamus, white matter (WM), cortical gray matter (cGM)], and disability outcomes. Similar analyses were performed for the recently diagnosed (within 3 years), treatment-naive patients (no prior disease-modifying therapy) subgroup.ResultsHigh versus low sNfL at baseline was prognostic of increased on-study T2 lesion formation at year 1 (relative increase: ofatumumab +158%; teriflunomide +69%, both p

Background Multiple sclerosis (MS) lesions typically form around a central vein that can be visualized with FLAIR* MRI, creating the central vein sign (CVS) which may reflect lesion pathophysiology. Herein we used gradient echo plural contrast imaging (GEPCI) MRI to simultaneously visualize CVS and measure tissue damage in MS lesions. We examined CVS in relation to tissue integrity in white matter (WM) lesions and among MS subtypes. Objective We aimed to determine if CVS positive lesions were specific to MS subtype, if CVS can be detected consistently among readers using the GEPCI method, and if there were differences in tissue damage in lesions with vs without CVS. Subjects and Methods Thirty relapsing-remitting MS (RRMS) subjects and 38 primary and secondary progressive MS (PMS) subjects were scanned with GEPCI protocol at 3T. GEPCI T2*-SWI images were generated to visualize CVS. Two investigators independently evaluated WM lesions for CVS and measured lesion volumes. To estimate tissue damage severity, total lesion volume, and mean lesion volume, R2t*-based tissue damage score (TDS) of individual lesions and tissue damage load (TDL) were measured for CVS+, CVS-, and confluent lesions. Spearman correlations were made between MRI and clinical data. One-way ANCOVA with age and sex as covariates was used to compare measurements of CVS+ vs CVS- lesions in each individual. Results 398 of 548 lesions meeting inclusion criteria showed CVS. Most patients had ≥40% CVS+ lesions. CVS+ lesions were present in similar proportion among MS subtypes. Interobserver agreement was high for CVS detection. CVS+ and confluent lesions had higher average and total volumes vs CVS- lesions. CVS+ and confluent lesions had more tissue damage than CVS- lesions based on TDL and mean TDS. Conclusion CVS occurred in RRMS and PMS in similar proportions. CVS+ lesions had greater tissue damage and larger size than CVS- lesions.

Summary: Background: Multiple sclerosis (MS) has a complex genetic, immune and metabolic pathophysiology. Recent studies implicated the gut microbiome in MS pathogenesis. However, interactions between the microbiome and host immune system, metabolism and diet have not been studied over time in this disorder. Methods: We performed a six-month longitudinal multi-omics study of 49 participants (24 untreated relapse remitting MS patients and 25 age, sex, race matched healthy control individuals. Gut microbiome composition and function were characterized using 16S and metagenomic shotgun sequencing. Flow cytometry was used to characterize blood immune cell populations and cytokine profiles. Circulating metabolites were profiled by untargeted UPLC-MS. A four-day food diary was recorded to capture the habitual dietary pattern of study participants. Findings: Together with changes in blood immune cells, metagenomic analysis identified a number of gut microbiota decreased in MS patients compared to healthy controls, and microbiota positively or negatively correlated with degree of disability in MS patients. MS patients demonstrated perturbations of their blood metabolome, such as linoleate metabolic pathway, fatty acid biosynthesis, chalcone, dihydrochalcone, 4-nitrocatechol and methionine. Global correlations between multi-omics demonstrated a disrupted immune-microbiome relationship and a positive blood metabolome-microbiome correlation in MS. Specific feature association analysis identified a potential correlation network linking meat servings with decreased gut microbe B. thetaiotaomicron, increased Th17 cell and greater abundance of meat-associated blood metabolites. The microbiome and metabolome profiles remained stable over six months in MS and control individuals. Interpretation: Our study identified multi-system alterations in gut microbiota, immune and blood metabolome of MS patients at global and individual feature level. Multi-OMICS data integration deciphered a potential important biological network that links meat intakes with increased meat-associated blood metabolite, decreased polysaccharides digesting bacteria, and increased circulating proinflammatory marker. Funding: This work was supported by the Washington University in St. Louis Institute of Clinical and Translational Sciences, funded, in part, by Grant Number # UL1 TR000448 from the National Institutes of Health, National Center for Advancing Translational Sciences, Clinical and Translational Sciences Award (Zhou Y, Piccio, L, Lovett-Racke A and Tarr PI); R01 NS10263304 (Zhou Y, Piccio L); the Leon and Harriet Felman Fund for Human MS Research (Piccio L and Cross AH). Cantoni C. was supported by the National MS Society Career Transition Fellowship (TA-180531003) and by donations from Whitelaw Terry, Jr. / Valerie Terry Fund. Ghezzi L. was supported by the Italian Multiple Sclerosis Society research fellowship (FISM 2018/B/1) and the National Multiple Sclerosis Society Post-Doctoral Fellowship (FG-190734474). Anne Cross was supported by The Manny & Rosalyn Rosenthal-Dr. John L. Trotter MS Center Chair in Neuroimmunology of the Barnes-Jewish Hospital Foundation. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Abstract A 35‐year‐old man with an enhancing tumefactive brain lesion underwent biopsy, revealing inflammatory demyelination. We used quantitative Gradient‐Recalled‐Echo (qGRE) MRI to visualize and measure tissue damage in the lesion. Two weeks after biopsy, qGRE showed significant R2t* reduction in the left optic radiation and surrounding tissue, consistent with the histopathological and clinical findings. qGRE was repeated 6 and 14 months later, demonstrating partially recovered optic radiation R2t*, in concert with improvement of the hemianopia to ultimately involve only the lower right visual quadrant. These results support qGRE metrics as in vivo biomarkers for tissue damage and longitudinal monitoring of demyelinating disease.

Abstract Objective Multiple sclerosis (MS) lesions are heterogeneous with regard to inflammation, demyelination, axonal injury, and neuronal loss. We previously developed a diffusion basis spectrum imaging (DBSI) technique to better address MS lesion heterogeneity. We hypothesized that the profiles of multiple DBSI metrics can identify lesion‐defining patterns. Here we test this hypothesis by combining a deep learning algorithm using deep neural network (DNN) with DBSI and other imaging methods. Methods Thirty‐eight MS patients were scanned with diffusion‐weighted imaging, magnetization transfer imaging, and standard conventional MRI sequences (cMRI). A total of 499 regions of interest were identified on standard MRI and labeled as persistent black holes (PBH), persistent gray holes (PGH), acute black holes (ABH), acute gray holes (AGH), nonblack or gray holes (NBH), and normal appearing white matter (NAWM). DBSI, diffusion tensor imaging (DTI), and magnetization transfer ratio (MTR) were applied to the 43,261 imaging voxels extracted from these ROIs. The optimized DNN with 10 fully connected hidden layers was trained using the imaging metrics of the lesion subtypes and NAWM. Results Concordance, sensitivity, specificity, and accuracy were determined for the different imaging methods. DBSI‐DNN derived lesion classification achieved 93.4% overall concordance with predetermined lesion types, compared with 80.2% for DTI‐DNN model, 78.3% for MTR‐DNN model, and 74.2% for cMRI‐DNN model. DBSI‐DNN also produced the highest specificity, sensitivity, and accuracy. Conclusions DBSI‐DNN improves the classification of different MS lesion subtypes, which could aid clinical decision making. The efficacy and efficiency of DBSI‐DNN shows great promise for clinical applications in automatic MS lesion detection and classification.

Abstract 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.

Several clinical trials have demonstrated the efficacy of lytic therapies targeting B cells in the treatment of relapsing multiple sclerosis (MS). More modest efficacy has been noted in the primary progressive subtype of MS. Clinical success has increased interest in the role of B cells in the pathogenesis of MS and in ways to potentially improve upon current B cell therapies. In this mini review, we will critically review previous and ongoing clinical trials of anti-CD20 monoclonal antibodies in MS, including rituximab, ocrelizumab, ofatumumab, and ublituximab. Side effects and adverse event profiles will be discussed. Studies examining the proposed mechanisms of action of B cell depleting therapies will also be reviewed.

Optic neuritis is a frequent first symptom of multiple sclerosis (MS) for which corticosteroids are a widely employed treatment option. The Optic Neuritis Treatment Trial (ONTT) reported that corticosteroid treatment does not improve long-term visual acuity, although the evolution of underlying pathologies is unclear. In this study, we employed non-invasive diffusion basis spectrum imaging (DBSI)-derived fiber volume to quantify 11% axonal loss 2 months after corticosteroid treatment (vs. baseline) in experimental autoimmune encephalomyelitis mouse optic nerves affected by optic neuritis. Longitudinal DBSI was performed at baseline (before immunization), after a 2-week corticosteroid treatment period, and 1 and 2 months after treatment, followed by histological validation of neuropathology. Pathological metrics employed to assess the optic nerve revealed axonal protection and anti-inflammatory effects of dexamethasone treatment that were transient. Two months after treatment, axonal injury and loss were indistinguishable between PBS- and dexamethasone-treated optic nerves, similar to results of the human ONTT. Our findings in mice further support that corticosteroid treatment alone is not sufficient to prevent eventual axonal loss in ON, and strongly support the potential of DBSI as an in vivo imaging outcome measure to assess optic nerve pathology.

Objective: To prospectively determine whether diffusion basis spectrum imaging (DBSI) detects, differentiates and quantitates coexisting inflammation, demyelination, axonal injury and axon loss in mice with optic neuritis (ON) due to experimental autoimmune encephalomyelitis (EAE), and to determine if DBSI accurately measures effects of fingolimod on underlying pathology. Methods: EAE was induced in 7-week-old C57BL/6 female mice. Visual acuity (VA) was assessed daily to detect onset of ON after which daily oral-treatment with either fingolimod (1 mg/kg) or saline was given for ten weeks. In vivo DBSI scans of optic nerves were performed at baseline, 2-, 6- and 10-weeks post treatment. DBSI-derived metrics including restricted isotropic diffusion tensor fraction (putatively reflecting cellularity), non-restricted isotropic diffusion tensor fraction (putatively reflecting vasogenic edema), DBSI-derived axonal volume, axial diffusivity, λ∥ (putatively reflecting axonal integrity), and increased radial diffusivity, λ⊥ (putatively reflecting demyelination). Mice were killed immediately after the last DBSI scan for immunohistochemical assessment. Results: Optic nerves of fingolimod-treated mice exhibited significantly better (p 0.05) from the baseline values in fingolimod-treated mice. Transient DBSI-λ∥ decrease and DBSI-λ⊥ increase were detected during Fingolimod treatment. DBSI-derived metrics assessed in vivo significantly correlated (p

Abstract Background Magnetic resonance imaging markers have been widely used to detect and quantify white matter pathologies in multiple sclerosis. We have recently developed a diffusion basis spectrum imaging (DBSI) to distinguish and quantify co-existing axonal injury, demyelination, and inflammation in multiple sclerosis patients and animal models. It could serve as a longitudinal marker for axonal loss, a primary cause of permanent neurological impairments and disease progression. Methods Eight 10-week-old female C57BL/6 mice underwent optic nerve DBSI, followed by a week-long recuperation prior to active immunization for experimental autoimmune encephalomyelitis (EAE). Visual acuity of all mice was assessed daily. Longitudinal DBSI was performed in mouse optic nerves at baseline (naïve, before immunization), before, during, and after the onset of optic neuritis. Tissues were perfusion fixed after final in vivo scans. The correlation between DBSI detected pathologies and corresponding immunohistochemistry markers was quantitatively assessed. Results In this cohort of EAE mice, monocular vision impairment occurred in all animals. In vivo DBSI detected, differentiated, and quantified optic nerve inflammation, demyelination, and axonal injury/loss, correlating nerve pathologies with visual acuity at different time points of acute optic neuritis. DBSI quantified, in the presence of optic nerve swelling, ~15% axonal loss at the onset of optic neuritis in EAE mice. Conclusions Our findings support the notion that axonal loss could occur early in EAE mice. DBSI detected pathologies in the posterior visual pathway unreachable by optical coherence tomography and without confounding inflammation induced optic nerve swelling. DBSI could thus decipher the interrelationship among various pathological components and the role each plays in disease progression. Quantification of the rate of axonal loss could potentially serve as the biomarker to predict treatment outcome and to determine when progressive disease starts.

Dietary interventions have not been effective in the treatment of multiple sclerosis (MS). Here, we show that periodic 3-day cycles of a fasting mimicking diet (FMD) are effective in ameliorating demyelination and symptoms in a murine experimental autoimmune encephalomyelitis (EAE) model. The FMD reduced clinical severity in all mice and completely reversed symptoms in 20% of animals. These improvements were associated with increased corticosterone levels and regulatory T (Treg) cell numbers and reduced levels of pro-inflammatory cytokines, TH1 and TH17 cells, and antigen-presenting cells (APCs). Moreover, the FMD promoted oligodendrocyte precursor cell regeneration and remyelination in axons in both EAE and cuprizone MS models, supporting its effects on both suppression of autoimmunity and remyelination. We also report preliminary data suggesting that an FMD or a chronic ketogenic diet are safe, feasible, and potentially effective in the treatment of relapsing-remitting multiple sclerosis (RRMS) patients (NCT01538355).

Cortical gray matter (GM) damage is now widely recognized in multiple sclerosis (MS). The standard MRI does not reliably detect cortical GM lesions, although cortical volume loss can be measured. In this study, we demonstrate that the gradient echo MRI can reliably and quantitatively assess cortical GM damage in MS patients using standard clinical scanners. High resolution multi-gradient echo MRI was used for regional mapping of tissue-specific MRI signal transverse relaxation rate values (R2*) in 10 each relapsing–remitting, primary-progressive and secondary-progressive MS subjects. A voxel spread function method was used to correct artifacts induced by background field gradients. R2* values from healthy controls (HCs) of varying ages were obtained to establish baseline data and calculate ΔR2* values – age-adjusted differences between MS patients and HC. Thickness of cortical regions was also measured in all subjects. In cortical regions, ΔR2* values of MS patients were also adjusted for changes in cortical thickness. Symbol digit modalities (SDMT) and paced auditory serial addition (PASAT) neurocognitive tests, as well as Expanded Disability Status Score, 25-foot timed walk and nine-hole peg test results were also obtained on all MS subjects. We found that ΔR2* values were lower in multiple cortical GM and normal appearing white matter (NAWM) regions in MS compared with HC. ΔR2* values of global cortical GM and several specific cortical regions showed significant (p

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.

In this study, axial (λ||) and radial (λ⊥) diffusivities derived from diffusion tensor imaging (DTI) were used to evaluate white matter injury in brains of mice affected by experimental autoimmune encephalomyelitis (EAE). Sixteen female C57BL/6 mice were immunized with amino acids 35–55 of myelin oligodendrocyte glycoprotein (MOG35–55). Three months after immunization, optic nerve and tract were severely affected with 19% and 18% decrease in λ|| respectively, suggesting the presence of axonal injury. In addition, a 156% and 86% increase in λ⊥ was observed in optic nerve and tract respectively, suggestive of myelin injury. After in vivo DTI, mice were perfusion fixed and immunohistochemistry for the identification of myelin basic protein (MBP) and phosphorylated neurofilament (pNF) was performed to verify the presence of axonal and myelin injury. The present study demonstrated that the visual pathway is selectively affected in MOG35–55 induced murine EAE and these injuries are non-invasively detectable using λ|| and λ⊥.

In the current study, the feasibility and reproducibility of in vivo diffusion tensor imaging (DTI) of the spinal cord in normal mice are illustrated followed by its application to mice with experimental allergic encephalomyelitis (EAE) to detect and differentiate axon and myelin damage. Axial diffusivity, describing water movement along the axonal fiber tract, in all regions of spinal cord white matter from EAE-affected C57BL/6 mice was significantly decreased compared to normal mice, whereas there was no statistically significant change in radial diffusivity, describing water movement across the fiber tract. Furthermore, a direct comparison between DTI and histology from a single mouse demonstrated a decrease in axial diffusivity that was supported by widespread staining of antibody against β-amyloid precursor protein. Regionally elevated radial diffusivity corresponded with locally diminished Luxol fast blue staining in the same tissue from the EAE mouse cord. Our findings suggest that axonal damage is more widespread than myelin damage in the spinal cord white matter of mice with EAE and that in vivo DTI may provide a sensitive and specific measure of white matter injury.

In multiple sclerosis (MS), the presence of B cells, plasma cells and excess immunoglobulins in central nervous system lesions and in the cerebrospinal fluid implicate the humoral immune system in disease pathogenesis. However, until the advent of specific B-cell-depleting therapies, the critical role of B cells and their products in MS was unproven. Rituximab, a monoclonal antibody that depletes B cells by targeting the CD20 molecule, has been shown to effectively reduce disease activity in patients with relapsing MS as a single agent. Our investigator-initiated phase II study is the only published clinical trial in which rituximab was used as an add-on therapy in patients with relapsing MS who had an inadequate response to standard injectable disease-modifying therapies (DMTs). The primary endpoint, magnetic resonance imaging (MRI) gadolinium-enhanced (GdE) lesion number before versus after rituximab, showed significant benefit of rituximab (74% of post-treatment MRI scans being free of GdE lesions compared with 26% free of GdE lesions at baseline; p < 0.0001). No differences were noted comparing patients on different DMTs. Several secondary clinical endpoints, safety and laboratory measurements (including B- and T-cell numbers in the blood and cerebrospinal fluid (CSF), serum and CSF chemokine levels, antibodies to myelin proteins) were assessed. Surprisingly, the decline in B-cell number was accompanied by a significant reduction in the number of T cells in both the peripheral blood and CSF. Rituximab therapy was associated with a significant decline of two lymphoid chemokines, CXCL13 and CCL19. No significant changes were observed in serum antibody levels against myelin proteins [myelin basic protein (MBP) and myelin/oligodendrocyte glycoprotein (MOG)] after treatment. These results suggest that B cells play a role in MS independent from antibody production and possibly related to their role in antigen presentation to T cells or to their chemokine/cytokine production.