Update on disease-modifying treatments for multiple sclerosis

ACKR3 Antagonism Enhances the Repair of Demyelinated Lesions Through Both Immunomodulatory and Remyelinating Effects

Addressing inflammation, demyelination, and associated neurodegeneration in inflammatory demyelinating diseases like multiple sclerosis (MS) remains challenging. ACT-1004-1239, a first-in-class and potent ACKR3 antagonist, currently undergoing clinical development, showed promise in preclinical MS models, reducing neuroinflammation and demyelination. However, its effectiveness in treating established disease and impact on remyelination after the occurrence of demyelinated lesions remain unexplored. This study assessed the therapeutic effect of ACT-1004-1239 in two demyelinating disease models. In the proteolipid protein (PLP)-induced experimental autoimmune encephalomyelitis (EAE) model, ACT-1004-1239 administered upon the detection of the first signs of paralysis, resulted in a dose-dependent reduction in EAE disease severity, concomitant with diminished immune cell infiltrates in the CNS and reduced demyelination. Notably, efficacy correlated with elevated plasma concentrations of CXCL11 and CXCL12, two pharmacodynamic biomarkers of ACKR3 antagonism. Combining ACT-1004-1239 with siponimod, an approved immunomodulatory treatment for MS, synergistically reduced EAE severity. In the cuprizone-induced demyelination model, ACT-1004-1239 administered after 5 weeks of cuprizone exposure, significantly accelerated remyelination, already quantifiable one week after cuprizone withdrawal. Additionally, ACT-1004-1239 penetrated the CNS, elevating brain CXCL12 concentrations. These results demonstrate that ACKR3 antagonism significantly reduces the severity of experimental demyelinating diseases, even when treatment is initiated therapeutically, after the occurrence of lesions. It confirms the dual mode of action of ACT-1004-1239, exhibiting both immunomodulatory effects by reducing neuroinflammation and promyelinating effects by accelerating myelin repair. The results further strengthen the rationale for evaluating ACT-1004-1239 in clinical trials for patients with demyelinating diseases.

Loss of miR-145 promotes remyelination and functional recovery in a model of chronic central demyelination

Strategies for treating progressive multiple sclerosis (MS) remain limited. Here, we found that miR-145-5p is overabundant uniquely in chronic lesion tissues from secondary progressive MS patients. We induced both acute and chronic demyelination in miR-145 knockout mice to determine its contributions to remyelination failure. Following acute demyelination, no advantage to miR-145 loss could be detected. However, after chronic demyelination, animals with miR-145 loss demonstrated increased remyelination and functional recovery, coincident with altered presence of astrocytes and microglia within the corpus callosum relative to wild-type animals. This improved response in miR-145 knockout animals coincided with a pathological upregulation of miR-145-5p in wild-type animals with chronic cuprizone exposure, paralleling human chronic lesions. Furthermore, miR-145 overexpression specifically in oligodendrocytes (OLs) severely stunted differentiation and negatively impacted survival. RNAseq analysis showed altered transcriptome in these cells with downregulated major pathways involved in myelination. Our data suggest that pathological accumulation of miR-145-5p is a distinctive feature of chronic demyelination and is strongly implicated in the failure of remyelination, possibly due to the inhibition of OL differentiation together with alterations in other glial cells. This is mirrored in chronic MS lesions, and thus miR-145-5p serves as a potential relevant therapeutic target in progressive forms of MS.

Treatment Patterns and Unmet Need for Patients with Progressive Multiple Sclerosis in the United States: Survey Results from 2016 to 2021

INTRODUCTION

Much of the current literature on treatment patterns and disability progression in multiple sclerosis (MS) does not distinguish between the relapsing-remitting and progressive subtypes (including primary [PPMS] and secondary progressive MS [SPMS]), or between active/nonactive disease. Current treatment options for progressive MS are limited, with only one approved product for PPMS and none specifically for nonactive SPMS. Here we report treatment patterns, disability progression, and unmet needs among patients with active and nonactive PPMS and SPMS.

METHODS

The annual, cross-sectional survey from the Adelphi Disease Specific Program was used to collect physician-reported data on US adult patients with PPMS and SPMS, including active and nonactive disease. Treatment patterns (including the proportion of patients who were untreated with a disease-modifying therapy [DMT]), disability progression, and unmet need are described from 2016 to 2021.

RESULTS

Data were collected for 2067 patients with progressive MS (PPMS, 1583; SPMS, 484). A substantial proportion of patients were untreated across all groups, and this was highest for nonactive PPMS (~ 43%). The proportion of untreated patients generally declined over time but remained high in 2018-2021 (~ 10-38%). Among treated patients, the proportion receiving infusions increased over time to ~ 34-46%, largely driven by ocrelizumab use after approval. Disability progression was reported for most patients (> 50%), including many who were receiving a DMT. Across all disease subtypes, when physicians were asked about the greatest unmet need with current DMTs, they most frequently cited effectiveness (~ 63-87%), and specifically slowing disease progression (~ 32-59%).

CONCLUSIONS

This analysis of physician-reported data reveals that patients with progressive MS, particularly those with nonactive disease, frequently remain untreated or continue to decline despite treatment with available DMTs. Thus there is an enduring need for safe and effective treatments for this underserved population.

Clinical use of dimethyl fumarate in multiple sclerosis treatment: an update to include China, using a modified Delphi method

Dimethyl fumarate (DMF) is a widely used oral disease-modifying therapy for multiple sclerosis (MS). Its efficacy and safety profiles are supported by over a decade of experience. Differences exist between Asia and Europe/United States in the prevalence and characteristics of MS; most data for DMF are derived from populations outside Asia. DMF was recently (2021) approved for use in China. The objectives of this review were to evaluate the evidence for DMF's profile, to provide an update to healthcare providers on current knowledge surrounding its use and to assess the relevance of existing data to use in China. This study used a modified Delphi method based on the insights of a scientific Steering Committee (SC), with a structured literature review conducted to assess the data of DMF. The literature review covered all papers in English (from 01 January 2011 to 21 February 2022) that include 'dimethyl fumarate' and 'multiple sclerosis', and their MeSH terms, on PubMed, supplemented by EMBASE and Citeline searches. Papers were categorized by topic and assessed for relevance and quality, before being used to formulate statements summarizing the literature on each subject. SC members voted on/revised statements, requiring ⩾80% agreement and ⩽10% disagreement for inclusion. Statements not reaching this level were discussed further until agreement was reached or until there was agreement to remove the statement. A total of 1030 papers were retrieved and used to formulate the statements and evidence summaries considered by the SC members. A total of 45 statements were agreed by the SC members. The findings support the positive efficacy and safety profile of DMF in treating patients with MS. Limited Chinese patient data are an ongoing consideration; however, based on current evidence, the statements are considered applicable to both the global and Chinese populations. DMF is a valuable addition to address unmet MS treatment needs in China. Registration: Not applicable.

Tension and trauma releasing exercises for people with multiple sclerosis - An exploratory pilot study

BACKGROUND AND AIM

Multiple sclerosis (MS) is characterized by increasing symptom burden leading many people with MS to use complementary treatments. TRE (Tension and Trauma Releasing Exercises) is a mind-body therapeutic method aiming to release muscle tension and stress. People with MS (PwMS) have reported benefits from TRE, but no scientific studies have investigated the effects of TRE on PwMS. Aim: To test a TRE program for PwMS and thereby explore outcome measures to be applied in future randomized studies.

EXPERIMENTAL PROCEDURE

A nine-week TRE program was completed by nine participants: Five were women, age ranged from 44 to 66 years, and time since diagnosis ranged from 2 to 21 years. Outcome measures included self-reported day-to-day levels of nine different symptoms as well as sleep quality and stress level. Modified Fatigue Impact Scale (MFIS) fatigue score and spasticity level of the ankle plantar flexors, assessed using a Portable Spasticity Assessment Device (PSAD), were measured pre and post intervention.

RESULTS

Decreases were seen in the mean scores of all nine self-reported day-to-day symptoms as well as stress level, while sleep quality mean score increased. LME analyses showed that all changes were statistically significant except one (bowel dysfunction). Mean MFIS-measured fatigue level decreased significantly from a score of 43.7 (SD = 13.6) to a score of 22.0 (SD = 12.3). No significant change was reported in PSAD-measured spasticity level.

CONCLUSION

The study indicates possible effects of TRE on PwMS on several self-reported outcome measures. Larger, randomized studies should be carried out to explore the findings further.

Clinical practice patterns in multiple sclerosis management: Mexican consensus recommendations

BACKGROUND

Multiple sclerosis affects more than 2 million people. Clinical decisions are performed under evidence-based medicine. The appearance of new disease-modifying therapies and changes in diagnostic criteria complicates the decision-making process in clinical practice.

OBJECTIVES

To characterize the criteria for radiologically isolated syndrome (RIS), clinically isolated syndrome (CIS), and relapsing-remitting multiple sclerosis (RRMS) by Mexican neurologists in a real-world setting.

METHODS

A two-round modified Delphi method (RAND/UCLA) was applied.

RESULTS

In RIS, LP, spinal cord MRI and VEP should be included in diagnostic testing; DMT initiation is not necessary. A follow-up MRI within 3 months are recommended. In CIS, corticosteroid therapy should be initiated at first relapse; both simple and Gd-enhanced MRI is mandatory. LP, selective blood tests, and NMO-IgG/AQP4 antibodies should be performed as complementary. IFN beta or GA were the most suitable DMTs for treating high-risk CIS. Patients with RRMS should begin with DMT at diagnosis, include a follow-up MRI if a patient had 2 relapses within 6 months. GA and oral DMTs are the most eligible DMTs for mild RRMS. Monoclonal antibodies-based therapy is chosen when disability is present. Radiological criteria for switching DMT included >1 Gd+ lesion and >2 new T2 lesions.

CONCLUSIONS

Although many coincidences, there are still many hollows in the medical attention of MS in Mexico. This consensus recommendation could be helpful to implement better evidence-based recommendations and guidelines in a real-world setting.

Design, synthesis, and biological evaluation of spiroindolines as novel inducers of oligodendrocyte progenitor cell differentiation-Use of a conformation-based hypothesis to facilitate compound design

Inducing oligodendrocyte progenitor cell (OPC) differentiation is a novel therapeutic strategy for the treatment of demyelinating diseases such as multiple sclerosis (MS). In the preceding article, we detailed the discovery of compound 1, a potent inducer of OPC differentiation possessing a characteristic spiroindoline structure. Also, we found that N-methylation and des-carbonyl compound 1 (4) led to a loss in potency. Herein, we describe our investigations of a conformation-based hypothesis for OPC differentiation activity based on the preferred conformation of the spiro core, and further structure-activity relationship (SAR) exploration led to the identification of 6-CF₃ derivative 8, which was more potent compared to compound 1.

The Gut Microbiota in Multiple Sclerosis: An Overview of Clinical Trials

Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating, and degenerative disease that affects the central nervous system. A recent study showed that interaction between the immune system and the gut microbiota plays a crucial role in the development of MS. This review reports the clinical studies carried out in recent years that aimed to evaluate the composition of the microbiota in patients with relapsing–remitting MS (RR-MS). We also report what is available in the literature regarding the effectiveness of fecal microbiota transplantation and the role of the diet in restoring the intestinal bacterial population. Studies report that patients with RR-MS have a microbiota that, compared with healthy controls, has higher amounts of Pedobacteria, Flavobacterium, Pseudomonas, Mycoplana, Acinetobacter, Eggerthella, Dorea, Blautia, Streptococcus and Akkermansia. In contrast, MS patients have a microbiota with impoverished microbial populations of Prevotella, Bacteroides, Parabacteroides, Haemophilus, Sutterella, Adlercreutzia, Coprobacillus, Lactobacillus, Clostridium, Anaerostipes and Faecalibacterium. In conclusion, the restoration of the microbial population in patients with RR-MS appears to reduce inflammatory events and the reactivation of the immune system.

Phenotypic Screening-Based Identification of 3,4-Disubstituted Piperidine Derivatives as Macrophage M2 Polarization Modulators: An Opportunity for Treating Multiple Sclerosis

Multiple sclerosis (MS) is a disease of the autoimmune-mediated disorder in the central nervous system, for which no effective therapeutic agent is currently available. The regulation of macrophage polarization toward M2 is a general benefit for treating MS. The gene biomarker-based phenotypic screening approach was developed, and 3,4-disubstituted piperidine derivative S-28 was identified as a lead compound modulating macrophage M2 polarization. Further SAR studies resulted in the discovery of the most potent modulator D11 that showed good oral bioavailability and significant in vivo therapeutic effects. Mechanistic studies demonstrated that the M2 polarization macrophages modulated by D11 mainly functioned through inhibiting the proliferation of T-cells and activating the phosphorylation of Stat3 and Akt. Therefore, the gene biomarker-based phenotypic screening was demonstrated as a promising tool for the discovery of novel macrophage M2 polarization modulators. Compound D11 may serve as a promising starting point for the development of therapeutics to treat MS.

Brazilian Consensus for the Treatment of Multiple Sclerosis: Brazilian Academy of Neurology and Brazilian Committee on Treatment and Research in Multiple Sclerosis

The expanding therapeutic arsenal in multiple sclerosis (MS) has allowed for more effective and personalized treatment, but the choice and management of disease-modifying therapies (DMTs) is becoming increasingly complex. In this context, experts from the Brazilian Committee on Treatment and Research in Multiple Sclerosis and the Neuroimmunology Scientific Department of the Brazilian Academy of Neurology have convened to establish this Brazilian Consensus for the Treatment of MS, based on their understanding that neurologists should be able to prescribe MS DMTs according to what is better for each patient, based on up-to-date evidence and practice. We herein propose practical recommendations for the treatment of MS, with the main focus on the choice and management of DMTs, as well as present a review of the scientific rationale supporting therapeutic strategies in MS.

Cladribine tablets added to IFN-β in active relapsing MS: The ONWARD study

Objective

To evaluate the safety and efficacy of cladribine tablets in patients still experiencing active relapsing MS despite interferon (IFN)-β treatment.

Methods

A 96-week phase II study, randomizing patients treated with IFN-β to cladribine tablets 3.5 mg/kg/IFN-β or placebo/IFN-β. Patients were to receive cladribine tablets 3.5 mg/kg/IFN-β or placebo/IFN-β in a 2:1 ratio (n = 172) with safety and exploratory efficacy outcomes being assessed.

Results

Adverse events (AEs) and serious AEs were similar across treatment groups, except lymphopenia. Fifty of 124 (40.3%) cladribine/IFN-β recipients vs 0% of placebo/IFN-β recipients reported lymphopenia as an AE, with grade 3/4 lymphopenia (laboratory lymphocyte count < 500 cells/mm³) experienced by 79/124 (63.7%) vs 1 (2.1%), respectively. Patients treated with cladribine tablets 3.5 mg/kg/IFN-β were 63% less likely to have a qualifying relapse than placebo/IFN-β recipients, and cladribine tablets 3.5 mg/kg/IFN-β reduced most MRI measures of disease activity.

Conclusions

In patients with active relapsing MS despite IFN-β treatment, cladribine tablets 3.5 mg/kg/IFN-β reduced relapses and MRI lesion activity over 96 weeks compared with placebo/IFN-β but led to an increased incidence of lymphopenia.

Classification of evidence

This study provides Class I evidence that for patients with active relapsing MS despite IFN-β treatment, cladribine tablets added to IFN-β reduced relapses and MRI lesion activity over 96 weeks and increased the incidence of lymphopenia.

Clinical trial registration

NCT00436826.

Lenalidomide regulates CNS autoimmunity by promoting M2 macrophages polarization

Multiple sclerosis (MS) is a chronic and debilitating neurological disorder of the central nervous system (CNS), characterized by infiltration of leukocytes into CNS and subsequent demyelination. Emerging evidences have revealed the beneficial roles of M2 macrophages in ameliorating experimental autoimmune encephalomyelitis (EAE), a model for MS. Here, we identify that lenalidomide alone could promote macrophages M2 polarization to prevent the progression of EAE, which is associated with subsequent inhibition of proinflammatory Th1 and Th17 cells both in peripheral lymph system and CNS. Depletion of macrophages by pharmacology treatment of clodronate liposomes or transferring lenalidomide-induced BMDMs in EAE mice completely abolished the therapeutic effect of lenalidomide or prevented EAE development, respectively. The macrophages-derived IL10 was upregulated both in vivo and in vitro after lenalidomide treatment. Moreover, lenalidomide-treated IL10-dificient EAE mice had higher clinical scores and more severe CNS damage, and intravenous injection of lenalidomide-treated IL10^−/− BMDMs into mice with EAE at disease onset did not reverse disease severity, implying IL10 may be essential in lenalidomide-ameliorated EAE. Mechanistically, lenalidomide significantly increased expression and autocrine secretion of IL10, subsequently activated STAT3-mediated expression of Ym1. These studies facilitate the development of potential novel therapeutic application of lenalidomide for the treatment of MS.

Efficacy of alemtuzumab and natalizumab in the treatment of different stages of multiple sclerosis patients

BACKGROUND

Multiple sclerosis (MS) is an autoimmune disease, in which the insulating covers of nerve cells in the brain and spinal cord are demyelinated. This study was conducted to compare the efficacy of alemtuzumab and natalizumab in the treatment of different stages of MS patients.

METHODS

A total of 585 patients diagnosed with MS and hospitalized were included and analyzed after which they were divided into the primary progressive MS A and B groups, the relapsing-remitting MS (RRMS) C and D groups, and the secondary progressive MS E and F groups. Patients in A, C, and E groups were administered alemtuzumab while those in B, D, and F groups were administered natalizumab for the treatment. The expanded disability status scale (EDSS) scores and the EDSS difference were calculated before and after treatment. The number of head magnetic resonance imaging enhanced lesions in the patients, recurrence time and recurrence rate were measured before and after treatment.

RESULTS

The EDSS score of the RRMS group was significantly lower than that of the primary progressive MS group and the secondary progressive MS group. After 12 months of treatment, the EDSS score of RRMS patients treated with natalizumab was significantly lower compared with the patients with alemtuzumab, and the difference before and after treatment was significantly higher than alemtuzumab. The recurrence rate of the RRMS-D group was significantly lower than the RRMS-C group. After 12 months of treatment, compared with the RRMS-C group, a significant reduction was observed in the number of head magnetic resonance imaging enhanced lesions and longer recurrence time in the RRMS-D group.

CONCLUSION

The efficacy of natalizumab was better than alemtuzumab in the treatment of patients in the RRMS group, while there was no significant difference among other stages of MS patients, which provided the theoretical basis and clinical guidance for the treatment of different stages of MS.

DAB389IL-2 recombinant fusion toxin effect on lymphocyte- and macrophage-producing cytokine subpopulation cells in experimentally induced demyelinating disease in mice

CONTEXT

We have reported previously that DAB389IL-2 recombinant fusion toxin targets IL-2R bearing CD4⁺ cells, and suppresses demyelinating disease in acute (A) - and chronic (C) - experimental autoimmune encephalomyelitis (EAE) animal models of multiple sclerosis.

OBJECTIVES

The present study was undertaken to investigate the effect of DAB389IL-2 treatment on various cytokine-secreting cell populations in A-EAE and C-EAE mice.

MATERIALS AND METHODS

The effects of DAB389IL-2 at doses of 200-, 800-, or 1600 kU administered i.v. on days 11-13 and 15 on the clinical score and cytokine-secreting cell populations were examined using flow cytometry.

RESULTS

C-EAE mice treated with 1600kU DAB389IL-2, but not A-EAE mice treated with 800 kU had significantly reduced disease. The CD3+CD25+ sub-population in spleens and spinal cords of A-EAE mice treated with 800 kU DAB389IL-2 a was increased, whereas in C-EAE mice treated with 1600 kU this population was increased. DAB₃₈₉IL-2 treatment reduced CD3⁺CD4⁺, CD3⁺CD8⁺, CD4⁺CD8⁺, CD3⁺IL-2⁺, CD3⁺IFN-γ⁺ and CD3⁺TNF-α⁺ T cell subpopulations in the spinal cord in A-EAE, and C-EAE mice on day 16. CD11b+ macrophages that were IL-2-, IFN-γ-, and TNF-α- positive were reduced in A-EAE mice. DAB389IL-2 treatment reduced CD19⁺ B-cells positive for IL-2 or CD11b⁺ in the spinal cord in acute and chronic disease. DAB389IL-2 treatment also reduced lymph node CD3⁺CD8⁺, CD4⁺CD8⁺, CD3⁺CD25⁺ populations on day 16, and lymph node CD3⁺IL-10⁺ and peripheral blood CD3⁺CD25⁺ populations on day 24.

DISCUSSION AND CONCLUSIONS

Our study demonstrates that DAB₃₈₉IL-2 fusion toxin suppresses EAE in a dose-dependent manner, and alters inflammatory cell sub-populations during disease development.

Quantifying the Benefits of Dimethyl Fumarate Over β Interferon and Glatiramer Acetate Therapies on Work Productivity Outcomes in MS Patients

Introduction

Dimethyl fumarate (DMF) is a novel oral therapy used for the treatment of relapse-remitting multiple sclerosis (RRMS). In two 2-year pivotal Phase 3 trials in patients with RRMS, DMF significantly reduced disease activity based on both clinical and magnetic resonance imaging (MRI) findings and demonstrated an acceptable safety profile. However, there is currently a lack of comparative data which explore the relationship between work productivity and health-related quality of life (HRQoL) outcomes in RRMS and how these differ among RRMS therapies, including DMF.

Methods

We explored this relationship through patient-reported data from the EuroQol Five-Dimensions (EQ-5D) tool, Work Productivity and Activity Impairment Questionnaire (WPAI), and the Hamburg Quality of Life Questionnaire in Multiple Sclerosis (HAQUAMS) using the Adelphi MS DSP® dataset.

Results

Our data demonstrated that patients receiving DMF experienced better outcomes, relative to patients receiving beta (β)interferons or glatiramer acetate, in all WPAI subscales [overall; average treatment effect (ATE) −13.92, 95% confidence interval (CI) −18.87 to −7.08; p < 0.001], EQ-5D (ATE +0.075, 95% Cl 0.014–0.136; p = 0.016) and HAQUAMS [ATE −0.45, 95% Cl −0.61 to −0.29; p < 0.001]. The EQ-5D and HAQUAMS were used with WPAI to determine the relationship between HRQoL outcomes and work productivity. Multiple linear regression analyses were performed, adjusting for age, sex, body mass index, ethnicity and number of comorbid conditions.

Conclusions

These data demonstrate that therapy with DMF was associated with increased work productivity and HRQoL for patients with RRMS and that these outcomes were consistently improved compared to outcomes with interferon and glatiramer acetate therapies.

Electroacupuncture Promotes Remyelination after Cuprizone Treatment by Enhancing Myelin Debris Clearance

Promoting remyelination is crucial for patients with demyelinating diseases including multiple sclerosis. However, it is still a circuitous conundrum finding a practical remyelinating therapy. Electroacupuncture (EA), originating from traditional Chinese medicine (TCM), has been widely used to treat CNS diseases all over the world, but the role of EA in demyelinating diseases is barely known. In this study, we examined the remyelinating properties and mechanisms of EA in cuprizone-induced demyelinating model, a CNS demyelinating murine model of multiple sclerosis. By feeding C57BL/6 mice with chow containing 0.2% cuprizone for 5 weeks, we successfully induce demyelination as proved by weight change, beam test, pole test, histomorphology, and Western Blot. EA treatment significantly improves the neurobehavioral performance at week 7 (2 weeks after withdrawing cuprizone chow). RNA-seq and RT-PCR results reveal up-regulated expression of myelin-related genes, and the expression of myelin associated protein (MBP, CNPase, and O4) are also increased after EA treatment, indicating therapeutic effect of EA on cuprizone model. It is widely acknowledged that microglia exert phagocytic effect on degraded myelin debris and clear these detrimental debris, which is a necessary process for subsequent remyelination. We found the remyelinating effect of EA is associated with enhanced clearance of degraded myelin debris as detected by dMBP staining and red oil O staining. Our further studies suggest that more microglia assemble in demyelinating area (corpus callosum) during the process of EA treatment, and cells inside corpus callosum are mostly in a plump, ameboid, and phagocytic shape, quite different from the ramified cells outside corpus callosum. RNA-seq result also unravels that most genes relating to positive regulation of phagocytosis (GO:0050766) are up-regulated, indicating enhanced phagocytic process after EA treatment. During the process of myelin debris clearance, microglia tend to change their phenotype toward M2 phenotype. Thus, we also probed into the phenotype of microglia in our study. Immuno-staining results show increased expression of CD206 and Arg1, and the ratio of CD206/CD16/32 are also higher in EA group. In conclusion, these results demonstrate for the first time that EA enhances myelin debris removal from activated microglia after demyelination, and promotes remyelination.

Oligodendrocyte regeneration: Its significance in myelin replacement and neuroprotection in multiple sclerosis

Oligodendrocytes readily regenerate and replace myelin membranes around axons in the adult mammalian central nervous system (CNS) following injury. The ability to regenerate oligodendrocytes depends on the availability of neural progenitors called oligodendrocyte precursor cells (OPCs) in the adult CNS that respond to injury-associated signals to induce OPC expansion followed by oligodendrocyte differentiation, axonal contact and myelin regeneration (remyelination). Remyelination ensures the maintenance of axonal conduction, and the oligodendrocytes themselves provide metabolic factors that are necessary to maintain neuronal integrity. Recent advances in oligodendrocyte regeneration research are beginning to shed light on critical intrinsic signals, as well as extrinsic, environmental factors that regulate the distinct steps of oligodendrocyte lineage progression and myelin replacement under CNS injury. These studies may offer novel pharmacological targets for regenerative medicine in inflammatory demyelinating disorders in the CNS such as multiple sclerosis. This article is part of the Special Issue entitled 'Oligodendrocytes in Health and Disease'.

Accelerated remyelination during inflammatory demyelination prevents axonal loss and improves functional recovery

Demyelination in MS disrupts nerve signals and contributes to axon degeneration. While remyelination promises to restore lost function, it remains unclear whether remyelination will prevent axonal loss. Inflammatory demyelination is accompanied by significant neuronal loss in the experimental autoimmune encephalomyelitis (EAE) mouse model and evidence for remyelination in this model is complicated by ongoing inflammation, degeneration and possible remyelination. Demonstrating the functional significance of remyelination necessitates selectively altering the timing of remyelination relative to inflammation and degeneration. We demonstrate accelerated remyelination after EAE induction by direct lineage analysis and hypothesize that newly formed myelin remains stable at the height of inflammation due in part to the absence of MOG expression in immature myelin. Oligodendroglial-specific genetic ablation of the M1 muscarinic receptor, a potent negative regulator of oligodendrocyte differentiation and myelination, results in accelerated remyelination, preventing axonal loss and improving functional recovery. Together our findings demonstrate that accelerated remyelination supports axonal integrity and neuronal function after inflammatory demyelination.

DOI:http://dx.doi.org/10.7554/eLife.18246.001

B Cells Are Multifunctional Players in Multiple Sclerosis Pathogenesis: Insights from Therapeutic Interventions

Multiple sclerosis (MS) is a severe disease of the central nervous system (CNS) characterized by autoimmune inflammation and neurodegeneration. Historically, damage to the CNS was thought to be mediated predominantly by activated pro-inflammatory T cells. B cell involvement in the pathogenesis of MS was solely attributed to autoantibody production. The first clues for the involvement of antibody-independent B cell functions in MS pathology came from positive results in clinical trials of the B cell-depleting treatment rituximab in patients with relapsing-remitting (RR) MS. The survival of antibody-secreting plasma cells and decrease in T cell numbers indicated the importance of other B cell functions in MS such as antigen presentation, costimulation, and cytokine production. Rituximab provided us with an example of how clinical trials can lead to new research opportunities concerning B cell biology. Moreover, analysis of the antibody-independent B cell functions in MS has gained interest since these trials. Limited information is present on the effects of current immunomodulatory therapies on B cell functions, although effects of both first-line (interferon, glatiramer acetate, dimethyl fumarate, and teriflunomide), second-line (fingolimod, natalizumab), and even third-line (monoclonal antibody therapies) treatments on B cell subtype distribution, expression of functional surface markers, and secretion of different cytokines by B cells have been studied to some extent. In this review, we summarize the effects of different MS-related treatments on B cell functions that have been described up to now in order to find new research opportunities and contribute to the understanding of the pathogenesis of MS.

JC polyomavirus mutants escape antibody-mediated neutralization

JC polyomavirus (JCV) persistently infects the urinary tract of most adults. Under conditions of immune impairment, JCV causes an opportunistic brain disease, progressive multifocal leukoencephalopathy (PML). JCV strains found in the cerebrospinal fluid of PML patients contain distinctive mutations in surface loops of the major capsid protein, VP1. We hypothesized that VP1 mutations might allow the virus to evade antibody-mediated neutralization. Consistent with this hypothesis, neutralization serology revealed that plasma samples from PML patients neutralized wild-type JCV strains but failed to neutralize patient-cognate PML-mutant JCV strains. This contrasted with serological results for healthy individuals, most of whom robustly cross-neutralized all tested JCV variants. Mice administered a JCV virus-like particle (VLP) vaccine initially showed neutralizing "blind spots" (akin to those observed in PML patients) that closed after booster immunization. A PML patient administered an experimental JCV VLP vaccine likewise showed markedly increased neutralizing titer against her cognate PML-mutant JCV. The results indicate that deficient humoral immunity is a common aspect of PML pathogenesis and that vaccination may overcome this humoral deficiency. Thus, vaccination with JCV VLPs might prevent the development of PML.

[Release-active antibodies to S100 protein are able to improve the experimental allergic encephalomyelitis]

AIM

To reveal the effects of release-active antibodies to S100 protein in an animal model of multiple sclerosis.

MATERIAL AND METHODS

Sixty female Wistar rats, aged 12 weeks, were included in the study. The pathology was induced by subcutaneous injection of the spinal cord homogenate. Afterwards the rats received a water solution of release-active antibodies to S100 protein (2,5 ml/kg/day, tenoten) or distilled water intragastrically during 30 days. Intramuscular injections of glatiramer acetate (4 mg/kg/day, copaxone) were used as a positive control.

RESULTS AND CONCLUSION

Release-active antibodies to S100 protein enhanced the latency period of the disease, reduced its peak intensity and compensated the loss of body weight of the animals. The experimental drug effect was similar to the results of copaxone injections.

Combination therapy with lenalidomide and nanoceria ameliorates CNS autoimmunity

OBJECTIVE

Multiple sclerosis (MS) is a debilitating neurological disorder involving an autoimmune reaction to oligodendrocytes and degeneration of the axons they ensheath in the CNS. Because the damage to oligodendrocytes and axons involves local inflammation and associated oxidative stress, we tested the therapeutic efficacy of combined treatment with a potent anti-inflammatory thalidomide analog (lenalidomide) and novel synthetic anti-oxidant cerium oxide nanoparticles (nanoceria) in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS.

METHODS

C57BL/6 mice were randomly assigned to a control (no EAE) group, or one of the four myelin oligodendrocyte glycoprotein-induced EAE groups: vehicle, lenalidomide, nanoceria, or lenalidomide plus nanoceria. During a 23 day period, clinical EAE symptoms were evaluated daily, and MRI brain scans were performed at 11-13 days and 20-22 days. Histological and biochemical analyses of brain tissue samples were performed to quantify myelin loss and local inflammation.

RESULTS

Lenalidomide treatment alone delayed symptom onset, while nanoceria treatment had no effect on symptom onset or severity, but did promote recovery; lenalidomide and nanoceria each significantly attenuated white matter pathology and associated inflammation. Combined treatment with lenalidomide and nanoceria resulted in a near elimination of EAE symptoms, and reduced white matter pathology and inflammatory cell responses to a much greater extent than either treatment alone.

INTERPRETATION

By suppressing inflammation and oxidative stress, combined treatment with lenalidomide and nanoceria can reduce demyelination and associated neurological symptoms in EAE mice. Our preclinical data suggest a potential application of this combination therapy in MS.

Treatment strategies for multiple sclerosis: When to start, when to change, when to stop?

Multiple sclerosis (MS) is a chronic inflammatory condition of the central nervous system determined by a presumed autoimmune process mainly directed against myelin components but also involving axons and neurons. Acute demyelination shows as clinical relapses that may fully or partially resolve, while chronic demyelination and neuroaxonal injury lead to persistent and irreversible neurological symptoms, often progressing over time. Currently approved disease-modifying therapies are immunomodulatory or immunosuppressive drugs that significantly although variably reduce the frequency of attacks of the relapsing forms of the disease. However, they have limited efficacy in preventing the transition to the progressive phase of MS and are of no benefit after it has started. It is therefore likely that the potential advantage of a given treatment is condensed in a relatively limited window of opportunity for each patient, depending on individual characteristics and disease stage, most frequently but not necessarily in the early phase of the disease. In addition, a sizable proportion of patients with MS may have a very mild clinical course not requiring a disease-modifying therapy. Finally, individual response to existing therapies for MS varies significantly across subjects and the risk of serious adverse events remains an issue, particularly for the newest agents. The present review is aimed at critically describing current treatment strategies for MS with a particular focus on the decision of starting, switching and stopping commercially available immunomodulatory and immunosuppressive therapies.

Proteomics of a conundrum: Thoughts on addressing the aetiology versus progression of multiple sclerosis

Currently in the field of multiple sclerosis (MS) research there is an ongoing debate concerning the cause of the disease. MS is widely considered to begin with an autoimmune dysregulation. The disease does have a prominent autoimmune component however this may be representative of a secondary effect. There is growing evidence that the disease may be initiated by an underlying degeneration of oligodendrocytes. In our viewpoint, we discuss the potential differences between the aetiology and progression of MS. For the most part, proteomic analysis has focused on the autoimmune component of the disease. We suggest that proteomic analysis should be applied to investigating oligodendrocyte degeneration. We discuss the potential of the cuprizone animal model of demyelination and its usefulness in understanding oligodendrocyte degeneration. Immune suppressive therapies are effective at reducing clinical symptoms and improving quality of life. However, a cure is still lacking and as such the disease does still progress. We suggest that if the initiating cause is poorly understood, then curing MS is unlikely.

Tolerance of activated pathogenic CD4+ T cells by transcriptional targeting of dendritic cells

We have recently shown that targeted expression of myelin oligodendrocyte glycoprotein (MOG) to dendritic cells with self-inactivating-lentivirus vectors induces antigen-specific tolerance in naive antigen-specific CD4+ T cells and protects mice from experimental autoimmune encephalomyelitis (EAE). In the present study, we demonstrate that this approach also induces tolerance of activated antigen-specific CD4+ T cells and completely protects mice from passive EAE induction. Tolerance induction did not correlate with the depletion of the preactivated antigen-specific CD4+ T cells. However, upon isolation and in vitro re-stimulation at day 6 after adoptive transfer the MOG-specific CD4+ T cells from the non-tolerized mice produced large amounts of inflammatory cytokines, whereas those from tolerized mice did not. This unresponsiveness correlated with the upregulation of regulatory molecules associated with anergy and regulatory T cells (Tregs). The in vivo depletion of Tregs resulted in EAE susceptibility of the tolerized animals, suggesting that these cells have indeed a role in tolerance induction/maintenance.

Dimethyl fumarate in the treatment of relapsing-remitting multiple sclerosis: an overview

Multiple sclerosis (MS) shares an immune-mediated origin with psoriasis. Long-term safety and efficacy data generated in Europe from usage of fumaric acid formulations in the latter disease constituted grounds to investigate their effects in MS patients. Dimethyl fumarate (DMF) was found to be the active principle in those formulations and in vitro studies have demonstrated that DMF has immune-modulatory properties exerted through abilities to divert cytokine production toward a Th2 profile, both on lymphocytes and microglial cells. More importantly, DMF was discovered to impact the anti-oxidative stress cell machinery promoting the transcription of genes downstream to the activation of the nuclear factor (erythroid derived 2)-like2 (NRF2). DMF exposure increases the cytosol concentrations of NRF2, which besides immune regulatory effects, has the potential for cytoprotection on glial cells, oligodendrocytes and neurons. Extensive and rigorous clinical trials have assessed the efficacy and safety of DMF at the dose of 240 mg twice and three times a day in relapsing-remitting MS patients during one phase IIb and two phase III trials. Robust, positive results were obtained across a number of clinical and paraclinical parameters. In one study (DEFINE), the relative reductions of the adjusted annualized relapse rate of the low and high dose regimens in comparison with placebo were 53% and 48%, respectively (p < 0.001 for both comparisons). In the other trial (CONFIRM), DMF decreased the annualized relapse rate in comparison with placebo by 44% in the lower and by 51% in higher dosage group (also p < 0.001). The number and size of lesions as detected by magnetic resonance imaging were also significantly decreased in comparison with the patients receiving DMF at every dosage. Multiple post hoc and subgroup analyses corroborated the clinical data, rendering DMF an appealing medication whose potential for impacting the degenerative aspects of MS remains to be explored.

Efficacy of fingolimod in patients with highly active relapsing-remitting multiple sclerosis

OBJECTIVE

There is a need to identify effective switch therapies for patients with relapsing-remitting multiple sclerosis (RRMS) who experience high disease activity despite receiving disease-modifying therapy (DMT). The objective of this study was to assess the efficacy of fingolimod versus placebo in patients with RRMS who had experienced high disease activity despite previously receiving DMT, using post hoc analyses of two phase 3 trials: FREEDOMS (NCT00289978) and FREEDOMS II (NCT00355134).

RESEARCH DESIGN AND METHODS

Clinical and magnetic resonance imaging outcomes over 24 months were analyzed in patients from FREEDOMS and FREEDOMS II who had received treatment in the previous year and had: (1) ≥1 relapse in the previous year and either ≥1 gadolinium (Gd) enhancing T1 lesion or ≥9 T2 lesions at baseline and/or (2) as many or more relapses in the year before baseline as in the previous year (as per fingolimod's EU label).

MAIN OUTCOME MEASURES

The inclusion criteria were fulfilled by 249 and 257 patients in the fingolimod and placebo groups, respectively. Annualized relapse rates were reduced by 48% for fingolimod versus placebo (p < 0.001). Fingolimod reduced the risk of 3 month and 6 month confirmed disability progression by 34% (p = 0.031) and 45% (p = 0.016), respectively, versus placebo. Brain volume loss was reduced by 46% for fingolimod versus placebo (p < 0.001). The reduction in Gd-enhancing T1 lesion counts for fingolimod versus placebo was 65% (p < 0.001). Furthermore, fingolimod reduced the number of new or newly enlarged T2 lesions by 69% relative to placebo (p < 0.001).

LIMITATION

The analyses are post hoc, but the population is specified by the European Medicines Agency in the label for fingolimod.

CONCLUSIONS

Fingolimod demonstrated efficacy across all four key RRMS disease measures analyzed in patients with high disease activity despite previous DMT.