Drugs in Development for Relapsing Multiple Sclerosis

Disease Modifying Strategies in Multiple Sclerosis: New Rays of Hope to Combat Disability?

Multiple sclerosis (MS) is the most prevalent chronic autoimmune inflammatory- demyelinating disorder of the central nervous system (CNS). It usually begins in young adulthood, mainly between the second and fourth decades of life. Usually, the clinical course is characterized by the involvement of multiple CNS functional systems and by different, often overlapping phenotypes. In the last decades, remarkable results have been achieved in the treatment of MS, particularly in the relapsing- remitting (RRMS) form, thus improving the long-term outcome for many patients. As deeper knowledge of MS pathogenesis and respective molecular targets keeps growing, nowadays, several lines of disease-modifying treatments (DMT) are available, an impressive change compared to the relative poverty of options available in the past. Current MS management by DMTs is aimed at reducing relapse frequency, ameliorating symptoms, and preventing clinical disability and progression. Notwithstanding the relevant increase in pharmacological options for the management of RRMS, research is now increasingly pointing to identify new molecules with high efficacy, particularly in progressive forms. Hence, future efforts should be concentrated on achieving a more extensive, if not exhaustive, understanding of the pathogenetic mechanisms underlying this phase of the disease in order to characterize novel molecules for therapeutic intervention. The purpose of this review is to provide a compact overview of the numerous currently approved treatments and future innovative approaches, including neuroprotective treatments as anti-LINGO-1 monoclonal antibody and cell therapies, for effective and safe management of MS, potentially leading to a cure for this disease.

The SphK1/S1P Axis Regulates Synaptic Vesicle Endocytosis via TRPC5 Channels

Sphingosine-1-phosphate (S1P), a bioactive sphingolipid concentrated in the brain, is essential for normal brain functions, such as learning and memory and feeding behaviors. Sphingosine kinase 1 (SphK1), the primary kinase responsible for S1P production in the brain, is abundant within presynaptic terminals, indicating a potential role of the SphK1/S1P axis in presynaptic physiology. Altered S1P levels have been highlighted in many neurologic diseases with endocytic malfunctions. However, it remains unknown whether the SphK1/S1P axis may regulate synaptic vesicle endocytosis in neurons. The present study evaluates potential functions of the SphK1/S1P axis in synaptic vesicle endocytosis by determining effects of a dominant negative catalytically inactive SphK1. Our data for the first time identify a critical role of the SphK1/S1P axis in endocytosis in both neuroendocrine chromaffin cells and neurons from mice of both sexes. Furthermore, our Ca2+ imaging data indicate that the SphK1/S1P axis may be important for presynaptic Ca2+ increases during prolonged stimulations by regulating the Ca2+ permeable TRPC5 channels, which per se regulate synaptic vesicle endocytosis. Collectively, our data point out a critical role of the regulation of TRPC5 by the SphK1/S1P axis in synaptic vesicle endocytosis.SIGNIFICANCE STATEMENT Sphingosine kinase 1 (SphK1), the primary kinase responsible for brain sphingosine-1-phosphate (S1P) production, is abundant within presynaptic terminals. Altered SphK1/S1P metabolisms has been highlighted in many neurologic disorders with defective synaptic vesicle endocytosis. However, whether the SphK1/S1P axis may regulate synaptic vesicle endocytosis is unknown. Here, we identify that the SphK1/S1P axis regulates the kinetics of synaptic vesicle endocytosis in neurons, in addition to controlling fission-pore duration during single vesicle endocytosis in neuroendocrine chromaffin cells. The regulation of the SphK1/S1P axis in synaptic vesicle endocytosis is specific since it has a distinguished signaling pathway, which involves regulation of Ca2+ influx via TRPC5 channels. This discovery may provide novel mechanistic implications for the SphK1/S1P axis in brain functions under physiological and pathologic conditions.

Strategy and application of manipulating DCs chemotaxis in disease treatment and vaccine design

As the most versatile antigen-presenting cells (APCs), dendritic cells (DCs) function as the cardinal commanders in orchestrating innate and adaptive immunity for either eliciting protective immune responses against canceration and microbial invasion or maintaining immune homeostasis/tolerance. In fact, in physiological or pathological conditions, the diversified migratory patterns and exquisite chemotaxis of DCs, prominently manipulate their biological activities in both secondary lymphoid organs (SLOs) as well as homeostatic/inflammatory peripheral tissues in vivo. Thus, the inherent mechanisms or regulation strategies to modulate the directional migration of DCs even could be regarded as the crucial cartographers of the immune system. Herein, we systemically reviewed the existing mechanistic understandings and regulation measures of trafficking both endogenous DC subtypes and reinfused DCs vaccines towards either SLOs or inflammatory foci (including neoplastic lesions, infections, acute/chronic tissue inflammations, autoimmune diseases and graft sites). Furthermore, we briefly introduced the DCs-participated prophylactic and therapeutic clinical application against disparate diseases, and also provided insights into the future clinical immunotherapies development as well as the vaccines design associated with modulating DCs mobilization modes.

Autoreactive lymphocytes in multiple sclerosis: Pathogenesis and treatment target

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by destruction of the myelin sheath structure. The loss of myelin leads to damage of a neuron’s axon and cell body, which is identified as brain lesions on magnetic resonance image (MRI). The pathogenesis of MS remains largely unknown. However, immune mechanisms, especially those linked to the aberrant lymphocyte activity, are mainly responsible for neuronal damage. Th1 and Th17 populations of lymphocytes were primarily associated with MS pathogenesis. These lymphocytes are essential for differentiation of encephalitogenic CD8⁺ T cell and Th17 lymphocyte crossing the blood brain barrier and targeting myelin sheath in the CNS. B-lymphocytes could also contribute to MS pathogenesis by producing anti-myelin basic protein antibodies. In later studies, aberrant function of Treg and Th9 cells was identified as contributing to MS. This review summarizes the aberrant function and count of lymphocyte, and the contributions of these cell to the mechanisms of MS. Additionally, we have outlined the novel MS therapeutics aimed to amend the aberrant function or counts of these lymphocytes.

Lymphocyte Counts and Multiple Sclerosis Therapeutics: Between Mechanisms of Action and Treatment-Limiting Side Effects

Although the detailed pathogenesis of multiple sclerosis (MS) is not completely understood, a broad range of disease-modifying therapies (DMTs) are available. A common side effect of nearly every MS therapeutic agent is lymphopenia, which can be both beneficial and, in some cases, treatment-limiting. A sound knowledge of the underlying mechanism of action of the selected agent is required in order to understand treatment-associated changes in white blood cell counts, as well as monitoring consequences. This review is a comprehensive summary of the currently available DMTs with regard to their effects on lymphocyte count. In the first part, we describe important general information about the role of lymphocytes in the course of MS and the essentials of lymphopenic states. In the second part, we introduce the different DMTs according to their underlying mechanism of action, summarizing recommendations for lymphocyte monitoring and definitions of lymphocyte thresholds for different therapeutic regimens.

Evaluation of the effect of fingolimod (FTY720) on macular perfusion by swept-source optical coherence tomography angiography in patients with multiple sclerosis

AIM

To determine changes in retinal microcirculation, caused by fingolimod (FTY720) use, via swept-source optical coherence tomography angiography (SS-OCTA) in relapsing-remitting multiple sclerosis (RR-MS) patients.

MATERIALS AND METHODS

80 patients with RR-MS, who were using fingolimod, and 50 healthy control subjects were included in the study. Group 1 consisted of 40 eyes from 40 RR-MS patients, who had been using fingolimod for less than six months, and Group 2 consisted of 40 eyes from 40 RR-MS patients, who had been using fingolimod for longer than six months. All participants underwent SS-OCTA via DRI OCT Triton (Topcon, Tokyo, Japan), analysing their central macular thickness (CMT) (µm), subfoveal choroidal thickness (SFCT) (µm), superficial (VDs) (%) and deep vascular plexuses (VDd) (%), choriocapillaris (VDcc) (%), and superficial and deep foveal avascular zones (FAZs, FAZd, respectively) (%) in mean values.

RESULTS

The mean follow-up times for patients in Groups 1 and 2 were 2.9 ± 1.5 months and 22.5 ± 11.3 months, respectively. The FAZs value in Group 2 was found to be significantly higher than that in both Group 1 and the control group (p = 0.034, p = 0.042, respectively). The VDs central value in Group 2 did not differ significantly from that in Group 1 or the control group (p > 0.05), while the VDs central value was higher in Group 1 than in the control group (p = 0.008). In Group 1, the VDd central value was significantly higher than in Group 2 and the control group (p = 0.047; p = 0.020, respectively). The CMT measurement for Group 2 was significantly lower than in Group 1 and the control group (p = 0.008, p = 0.003, respectively).

CONCLUSION

Fingolimod use seems to remarkably increase VDs and VDd measurements in the early period of administration and decrease CMT over a longer period of administration in patients with RR-MS.

Kynurenines in the Pathogenesis of Multiple Sclerosis: Therapeutic Perspectives

Over the past years, an increasing amount of evidence has emerged in support of the kynurenine pathway’s (KP) pivotal role in the pathogenesis of several neurodegenerative, psychiatric, vascular and autoimmune diseases. Different neuroactive metabolites of the KP are known to exert opposite effects on neurons, some being neuroprotective (e.g., picolinic acid, kynurenic acid, and the cofactor nicotinamide adenine dinucleotide), while others are toxic to neurons (e.g., 3-hydroxykynurenine, quinolinic acid). Not only the alterations in the levels of the metabolites but also disturbances in their ratio (quinolinic acid/kynurenic acid) have been reported in several diseases. In addition to the metabolites, the enzymes participating in the KP have been unearthed to be involved in modulation of the immune system, the energetic upkeep of neurons and have been shown to influence redox processes and inflammatory cascades, revealing a sophisticated, intertwined system. This review considers various methods through which enzymes and metabolites of the kynurenine pathway influence the immune system, the roles they play in the pathogenesis of neuroinflammatory diseases based on current evidence with a focus on their involvement in multiple sclerosis, as well as therapeutic approaches.

Safety of long-term intrathecal methotrexate in progressive forms of MS

Background

There are few treatment options for multiple sclerosis (MS) patients with advanced disability [expanded disability status scale (EDSS) ⩾ 6.0]. In 2010, we reported initial results of using intrathecal methotrexate (ITMTX) in patients with progressive MS. We now report on long-term use of ITMTX. We performed a retrospective chart analysis of patients who have had 18 or more treatments to establish the ongoing safety and tolerability of ITMTX. Thus, the objective of this study was to establish the safety and tolerability of long-term therapy with (ITMTX) in patients with treatment-resistant, progressive forms of MS.

Methods

We studied 83 patients (67 secondary and 16 primary progressive) who received ITMTX 12.5 mg every 8-11 weeks for 3-10 years (range: 18-57 treatments). All patients were evaluated neurologically, and their EDSS was assessed at every treatment. In addition, all adverse events, frequency of infections, and any hospitalizations, were noted.

Results

There were no deaths, hospitalizations, or other serious adverse effects related to ITMTX. Headaches occurred at least once in 12% of patients, and transient fatigue occurred in 53% of patients. As determined by EDSS, there was no significant change from baseline status to post-treatment scores in both primary progressive MS (PPMS) and secondary progressive (SPMS) patients.

Conclusions

Pulsed ITMTX was well tolerated for up to 10 years in PPMS patients with no serious adverse effects. Although this was an open-label, retrospective analysis, and efficacy could not be studied, there was evidence of disease stabilization in many patients receiving ITMTX. It appears that long-term ITMTX is a safe therapeutic option in advanced progressive MS.

Immunological Aspects of Approved MS Therapeutics

Multiple sclerosis (MS) is the most common neurological immune-mediated disease leading to disability in young adults. The outcome of the disease is unpredictable, and over time, neurological disabilities accumulate. Interferon beta-1b was the first drug to be approved in the 1990s for relapsing-remitting MS to modulate the course of the disease. Over the past two decades, the treatment landscape has changed tremendously. Currently, more than a dozen drugs representing 1 substances with different mechanisms of action have been approved (interferon beta preparations, glatiramer acetate, fingolimod, siponimod, mitoxantrone, teriflunomide, dimethyl fumarate, cladribine, alemtuzumab, ocrelizumab, and natalizumab). Ocrelizumab was the first medication to be approved for primary progressive MS. The objective of this review is to present the modes of action of these drugs and their effects on the immunopathogenesis of MS. Each agent's clinical development and potential side effects are discussed.

Potential Role of Flavonoids in Treating Chronic Inflammatory Diseases with a Special Focus on the Anti-Inflammatory Activity of Apigenin

Inflammation has been reported to be intimately linked to the development or worsening of several non-infectious diseases. A number of chronic conditions such as cancer, diabetes, cardiovascular disorders, autoimmune diseases, and neurodegenerative disorders emerge as a result of tissue injury and genomic changes induced by constant low-grade inflammation in and around the affected tissue or organ. The existing therapies for most of these chronic conditions sometimes leave more debilitating effects than the disease itself, warranting the advent of safer, less toxic, and more cost-effective therapeutic alternatives for the patients. For centuries, flavonoids and their preparations have been used to treat various human illnesses, and their continual use has persevered throughout the ages. This review focuses on the anti-inflammatory actions of flavonoids against chronic illnesses such as cancer, diabetes, cardiovascular diseases, and neuroinflammation with a special focus on apigenin, a relatively less toxic and non-mutagenic flavonoid with remarkable pharmacodynamics. Additionally, inflammation in the central nervous system (CNS) due to diseases such as multiple sclerosis (MS) gives ready access to circulating lymphocytes, monocytes/macrophages, and dendritic cells (DCs), causing edema, further inflammation, and demyelination. As the dearth of safe anti-inflammatory therapies is dire in the case of CNS-related disorders, we reviewed the neuroprotective actions of apigenin and other flavonoids. Existing epidemiological and pre-clinical studies present considerable evidence in favor of developing apigenin as a natural alternative therapy against chronic inflammatory conditions.

RhoA Drives T-Cell Activation and Encephalitogenic Potential in an Animal Model of Multiple Sclerosis

T-cells are known to be intimately involved in the pathogenesis of multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). T-cell activation is controlled by a range of intracellular signaling pathways regulating cellular responses such as proliferation, cytokine production, integrin expression, and migration. These processes are crucial for the T-cells’ ability to mediate inflammatory processes in autoimmune diseases such as MS. RhoA is a ubiquitously expressed small GTPase well described as a regulator of the actin cytoskeleton. It is essential for embryonic development and together with other Rho GTPases controls various cellular processes such as cell development, shaping, proliferation, and locomotion. However, the specific contribution of RhoA to these processes in T-cells in general, and in autoreactive T-cells in particular, has not been fully characterized. Using mice with a T-cell specific deletion of the RhoA gene (RhoA^fl/flLckCre⁺), we investigated the role of RhoA in T-cell development, functionality, and encephalitogenic potential in EAE. We show that lack of RhoA specifically in T-cells results in reduced numbers of mature T-cells in thymus and spleen but normal counts in peripheral blood. EAE induction in RhoA^fl/flLckCre⁺ mice results in significantly reduced disease incidence and severity, which coincides with a reduced CNS T-cell infiltration. Besides presenting reduced migratory capacity, both naïve and autoreactive effector T-cells from RhoA^fl/flLckCre⁺ mice show decreased viability, proliferative capacity, and an activation profile associated with reduced production of Th1 pro-inflammatory cytokines. Our study demonstrates that RhoA is a central regulator of several archetypical T-cell responses, and furthermore points toward RhoA as a new potential therapeutic target in diseases such as MS, where T-cell activity plays a central role.

Secondary antibody deficiency: a complication of anti-CD20 therapy for neuroinflammation

B-cell depleting anti-CD20 monoclonal antibody therapies are being increasingly used as long-term maintenance therapy for neuroinflammatory disease compared to many non-neurological diseases where they are used as remission-inducing agents. While hypogammaglobulinaemia is known to occur in over half of patients treated with medium to long-term B-cell-depleting therapy (in our cohort IgG 38, IgM 56 and IgA 18%), the risk of infections it poses seems to be under-recognised. Here, we report five cases of serious infections associated with hypogammaglobulinaemia occurring in patients receiving rituximab for neuromyelitis optica spectrum disorders. Sixty-four per cent of the whole cohort of patients studied had hypogammaglobulinemia. We discuss the implications of these cases to the wider use of anti-CD20 therapy in neuroinflammatory disease.

Alemtuzumab versus interferon beta 1a for relapsing-remitting multiple sclerosis

BACKGROUND

Alemtuzumab is a humanised monoclonal antibody that alters the circulating lymphocyte pool, causing prolonged lymphopenia, thus remoulding the immune repertoire that accompanies homeostatic lymphocyte reconstitution. It has been proved more effective than interferon (IFN) 1a for the treatment of relapsing-remitting multiple sclerosis (RRMS).

OBJECTIVES

To compare the efficacy, tolerability and safety of alemtuzumab versus interferon beta 1a in the treatment of people with RRMS to prevent disease activity.

SEARCH METHODS

We searched the Cochrane Multiple Sclerosis and Rare Diseases of the CNS Group Trials Register (1 February 2017) which, among other sources, contains records from CENTRAL, MEDLINE, Embase, CINAHL, LILACS, PEDRO and the trial registry databases Clinical Trials.gov and WHO International Clinical Trials Registry Platform for all prospectively registered and ongoing trials.

SELECTION CRITERIA

All double-blind, randomised, controlled trials comparing intravenous alemtuzumab (12 mg per day or 24 mg per day on five consecutive days during the first month and on three consecutive days at months 12 and 24) versus subcutaneous IFN beta 1a (22 μg or 44 μg three times per week (Rebif) or intramuscular injection 30 μg once a week (Avonex)) in people of any gender and age with RRMS.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included three trials involving 1694 participants. All trials compared alemtuzumab 12 mg per day or 24 mg per day versus IFN beta 1a for treating RRMS. In CAMMS223, participants received either subcutaneous IFN beta 1a 44 μg three times per week or annual intravenous cycles of alemtuzumab (at a dose of 12 mg per day or 24 mg per day) for 36 months. In CARE-MS I and CARE-MS II, participants received subcutaneous IFN beta 1a 44 μg three times per week or annual intravenous cycles of alemtuzumab 12 mg per day for 24 months. The methodological quality was good for all three studies.In the alemtuzumab 12 mg per day group, the results showed statistically significant difference in reducing relapses (risk ratio (RR) 0.60, 95% confidence interval (CI) 0.52 to 0.70), preventing disease progression (RR 0.60, 95% CI 0.45 to 0.79) and developing new T2 lesions on magnetic resonance imaging (RR 0.75, 95% CI 0.61 to 0.93) after 24 and 36 months' follow-up, but found no statistically significant difference in the changes of Expanded Disability Status Scale (EDSS) score (mean difference (MD) -0.35, 95% CI -0.73 to 0.03). In the alemtuzumab 24 mg per day group, the results showed statistically significant differences in reducing relapses (RR 0.38, 95% CI 0.23 to 0.62), preventing disease progression (RR 0.42, 95% CI 0.21 to 0.84) and the changes of EDSS score (MD -0.83, 95% CI -1.17 to -0.49) after 36 months' follow-up.All three trials reported adverse events and serious adverse events. There was no statistically significant difference in the number of participants with at least one adverse event (RR 1.03, 95% CI 0.97 to 1.08) and the number of participants who experienced serious adverse events (RR 1.03, 95% CI 0.83 to 4.54).

AUTHORS' CONCLUSIONS

There is low- to moderate-quality evidence that annual intravenous cycles of alemtuzumab at a dose of 12 mg per day or 24 mg per day reduces the proportion of participants with relapses, disease progression, change of EDSS score and developing new T2 lesions on MRI over 24 to 36 months in comparison with subcutaneous IFN beta-1a 44 μg three times per week.Alemtuzumab appeared to be relatively well tolerated. The most frequently reported adverse events were infusion-associated reactions, infections and autoimmune events. The use of alemtuzumab requires careful monitoring so that potentially serious adverse effects can be treated early and effectively.

Anti-inflammatory drug, leflunomide and its metabolite teriflunomide inhibit NSCLC proliferation in vivo and in vitro

Lung cancer causes more than 150000 deaths annually in the United States alone, of which non-small cell lung cancer (NSCLC) accounts for 80%. Our studies demonstrated that NSCLC cells were sensitive to leflunomide and its metabolite teriflunomide, a FDA approved drug, which was a well-known immunomodulatory drug for relapsing multiple sclerosis (MS). In the present studies, we found first time that they displayed anti-tumor activity of NSCLC in vitro and in vivo. Potent anti-cancer effects in NSCLC in vitro, including inhibiting NSCLC cells viability, arresting cell cycle at the G0/G1 phase, inducing cell apoptosis, delaying and suppressing NSCLC cells colony-forming ability and cell motility, could be achieved with this agent. Meanwhile, we provided evidence that these effects were applicable in vivo by using H460 cells xenograft model in nude mice. In addition, to comprehensively clarify the mechanisms of teriflunomide in NSCLC, we explored a genome-wide transcriptomic analysis, and found that teriflunomide was involved in multiple signaling pathways and cellular processes, such as cell cycle, apoptosis, MAPK and p53 signaling pathway. Taken together, the results of our studies provided insights into a novel anti-cancer effect of leflunomide and teriflunomide on NSCLC and might open new therapeutic avenues for the treatment of NSCLC.

Natalizumab for Multiple Sclerosis: A Case in Point for the Impact of Translational Neuroimmunology

Advances in translational neuroimmunology over the last two decades have revolutionized the treatment of relapsing forms of multiple sclerosis. A pathological hallmark of multiple sclerosis is the presence of leukocytes in the areas of disease activity in the CNS. Natalizumab inhibits the trafficking of lymphocytes from the blood into the brain and spinal cord by blocking the adhesion molecule α₄-integrin. Representing the enormous success of a molecular targeted approach, natalizumab was the first mAb approved for the treatment of relapsing-remitting multiple sclerosis. However, only a few months after its approval, natalizumab was withdrawn from the market because of an unanticipated life threatening adverse effect: progressive multifocal leukoencephalopathy. Natalizumab was later reintroduced with required adherence to a strict monitoring program. In this article, we review the bench-to-bedside journey of natalizumab, along with the lessons learned from postmarketing studies.

Paediatric Multiple Sclerosis: Update on Diagnostic Criteria, Imaging, Histopathology and Treatment Choices

Paediatric multiple sclerosis (MS) represents less than 5 % of the MS population, but patients with paediatric-onset disease reach permanent disability at a younger age than adult-onset patients. Accurate diagnosis at presentation and optimal long-term treatment are vital to mitigate ongoing neuroinflammation and irreversible neurodegeneration. However, it may be difficult to early differentiate paediatric MS from acute disseminated encephalomyelitis (ADEM) and neuromyelitis optica spectrum disorders (NMOSD), as they often have atypical presentation that differs from that of adult-onset MS. The purpose of this review is to summarize the updated views on diagnostic criteria, imaging, histopathology and treatment choices.

Daclizumab: A Review in Relapsing Multiple Sclerosis

Daclizumab (Zinbryta^®; previously known as daclizumab high-yield process) is a therapeutic monoclonal antibody that has recently been approved for the treatment of relapsing forms of multiple sclerosis (MS) in adults. Daclizumab is a humanized IgG1 monoclonal antibody directed against CD25, the alpha subunit of the high-affinity interleukin-2 receptor. As demonstrated in the phase III DECIDE trial, once-monthly subcutaneous daclizumab was superior to once-weekly intramuscular interferon (IFN) β-1a in reducing the clinical relapse rate and radiological measures of disease in patients with relapsing-remitting MS. In addition, daclizumab has demonstrated efficacy in reducing disability progression and in improving health-related quality of life in patients with relapsing MS. Ongoing open-label clinical trials indicate that daclizumab's efficacy is maintained in the longer term (3 years or more). Daclizumab appears to be generally well tolerated, with adverse events of interest (including hepatic, infectious and cutaneous events) generally manageable with regular monitoring and/or standard therapies. The place of daclizumab in MS treatment remains to be fully determined. However, based on available evidence, daclizumab provides a useful alternative option to other currently available disease-modifying therapies in the treatment of relapsing MS.

Fingolimod (Gilenya® ) in multiple sclerosis: bradycardia, atrioventricular blocks, and mild effect on the QTc interval. Something to do with the L-type calcium channel?

Cardiac arrhythmias and ECG abnormalities including bradycardia, prolongation of the QT interval, and atrioventricular (AV) conduction blocks have been extensively observed with fingolimod, the first marketed oral drug for treating the relapsing-remitting form of multiple sclerosis. This study was aiming to further elucidate the effects of fingolimod on cardiac electrophysiology at three different levels: (i) in vitro, (ii) ex vivo, and (iii) in vivo. (i) Patch-clamp experiments in whole cell configuration were performed on Ca_v 1.2-transfected tsA201 cells exposed to fingolimod-phosphate 100 or 500 nmol/L (n = 27 cells, total) to measure drug effect on L-type calcium current (I_CaL ). (ii) Langendorff perfusion experiments were undertaken on male Hartley guinea-pigs isolated hearts (n = 4) exposed to fingolimod 10 and 100 nmol/L to evaluate drug-induced effects on monophasic action potential duration measured at 90% repolarization (MAPD₉₀ ). (iii) Implanted cardiac telemeters were used to record ECGs in guinea-pigs (n = 7) treated with a single dose of fingolimod 0.0625 mg/kg suspension, administered as an oral gavage. (i) In vitro cellular experiments showed that fingolimod-phosphate causes a concentration-dependent reduction in I_CaL . (ii) Ex vivo Langendorff experiments revealed that fingolimod had no significant effect on MAPD₉₀ . (iii) Fingolimod caused significant prolongations of the RR, PR, QT, and QTc_F intervals in vivo. Reversible AV blocks were also observed in 7/7 animals. Fingolimod possesses I_CaL -blocking properties, further contributing to its AV conduction-slowing effects. These properties are also consistent with its mitigated effect on the QT interval in humans, despite previously shown HERG-blocking effect.

Myeloid cells - targets of medication in multiple sclerosis

Discussions of multiple sclerosis (MS) pathophysiology tend to focus on T cells and B cells of the adaptive immune response. The innate immune system is less commonly considered in this context, although dendritic cells, monocytes, macrophages and microglia - collectively referred to as myeloid cells - have prominent roles in MS pathogenesis. These populations of myeloid cells function as antigen-presenting cells and effector cells in neuroinflammation. Furthermore, a vicious cycle of interactions between T cells and myeloid cells exacerbates pathology. Several disease-modifying therapies are now available to treat MS, and insights into their mechanisms of action have largely focused on the adaptive immune system, but these therapies also have important effects on myeloid cells. In this Review, we discuss the evidence for the roles of myeloid cells in MS and the experimental autoimmune encephalomyelitis model of MS, and consider how interactions between myeloid cells and T cells and/or B cells promote MS pathology. Finally, we discuss the direct and indirect effects of existing MS medications on myeloid cells.

Fingolimod for relapsing-remitting multiple sclerosis

BACKGROUND

Fingolimod was approved in 2010 for the treatment of patients with the relapsing-remitting (RR) form of multiple sclerosis (MS). It was designed to reduce the frequency of exacerbations and to delay disability worsening. Issues on its safety and efficacy, mainly as compared to other disease modifying drugs (DMDs), have been raised.

OBJECTIVES

To assess the safety and benefit of fingolimod versus placebo, or other disease-modifying drugs (DMDs), in reducing disease activity in people with relapsing-remitting multiple sclerosis (RRMS).

SEARCH METHODS

We searched the Cochrane Multiple Sclerosis and Rare Diseases of the Central Nervous System (CNS) Group's Specialised Trials Register and US Food and Drug Administration reports (15 February 2016).

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing the beneficial and harmful effects of fingolimod versus placebo or other approved DMDs in people with RRMS.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane.

MAIN RESULTS

Six RCTs met our selection criteria. The overall population included 5152 participants; 1621 controls and 3531 treated with fingolimod at different doses; 2061 with 0.5 mg, 1376 with 1.25 mg, and 94 with 5.0 mg daily. Among the controls, 923 participants were treated with placebo and 698 with others DMDs. The treatment duration was six months in three, 12 months in one, and 24 months in two trials. One study was at high risk of bias for blinding, three studies were at high risk of bias for incomplete outcome reporting, and four studies were at high risk of bias for other reasons (co-authors were affiliated with the pharmaceutical company). We retrieved 10 ongoing trials; four of them have been completed.Comparing fingolimod administered at the approved dose of 0.5 mg to placebo, we found that the drug at 24 months increased the probability of being relapse-free (risk ratio (RR) 1.44, 95% confidence interval (CI) (1.28 to 1.63); moderate quality of evidence), but it might lead to little or no difference in preventing disability progression (RR 1.07, 95% CI 1.02 to 1.11; primary clinical endpoints; low quality evidence). Benefit was observed for other measures of inflammatory disease activity including clinical (annualised relapse rate): rate ratio 0.50, 95% CI 0.40 to 0.62; moderate quality evidence; and magnetic resonance imaging (MRI) activity (gadolinium-enhancing lesions): RR of being free from (MRI) gadolinium-enhancing lesions: 1.36, 95% CI 1.27 to 1.45; low quality evidence.The mean change of MRI T2-weighted lesion load favoured fingolimod at 12 and 24 months.No significant increased risk of discontinuation due to adverse events was observed for fingolimod 0.5 mg compared to placebo at six and 24 months. The risk of fingolimod discontinuation was significantly higher compared to placebo for the dose 1.25 mg at 24 months (RR 1.93, 95% CI 1.48 to 2.52).No significant increased risk of discontinuation due to serious adverse events was observed for fingolimod 0.5 mg compared to placebo at six and 24 months. A significant increased risk of discontinuation due to serious adverse events was found for fingolimod 5.0 mg (RR 2.77, 95% CI 1.04 to 7.38) compared to placebo at six months.Comparing fingolimod 0.5 mg to intramuscular interferon beta-1a, we found moderate quality evidence that the drug at one year slightly increased the number of participants free from relapse (RR 1.18, 95% CI 1.09 to 1.27) or from gadolinium-enhancing lesions (RR 1.12, 95% CI 1.05 to 1.19), and decreased the relapse rate (rate ratio 0.48, 95% CI 0.34 to 0.70). We did not detect any advantage for preventing disability progression (RR 1.02, 95% CI 0.99 to 1.06; low quality evidence). We did not detect any significant difference for MRI T2-weighted lesion load change.We found a greater likelihood of participants discontinuing fingolimod, as compared to other DMDs, due to adverse events in the short-term (six months) (RR 3.21, 95% CI 1.16 to 8.86), but there was no significant difference versus interferon beta-1a at 12 months (RR 1.51, 95% CI 0.81 to 2.80; moderate quality evidence). A higher incidence of adverse events was suggestive of the lower tolerability rate of fingolimod compared to interferon-beta 1a.Quality of life was improved in participants after switching from a different DMD to fingolimod at six months, but this effect was not found compared to placebo at 24 months.All studies were sponsored by Novartis Pharma.

AUTHORS' CONCLUSIONS

Treatment with fingolimod compared to placebo in RRMS patients is effective in reducing inflammatory disease activity, but it may lead to little or no difference in preventing disability worsening. The risk of withdrawals due to adverse events requires careful monitoring of patients over time. The evidence on the risk/benefit profile of fingolimod compared with intramuscular interferon beta-1a was uncertain, based on a low number of head-to-head RCTs with short follow-up duration. The ongoing trial results will possibly satisfy these issues.

Apigenin, a Natural Flavonoid, Attenuates EAE Severity Through the Modulation of Dendritic Cell and Other Immune Cell Functions

Apigenin, a natural flavonoid, found in several plants, fruits, vegetables, herbs, and spices, is known to have anti-oxidant and anti-inflammatory properties that are evident in the use of these substances for centuries as medicinal approaches to treat asthma, insomnia, Parkinson's disease, neuralgia, and shingles. However, there is a considerable dearth of information regarding its effect on immune cells, especially dendritic cells (DC) that maintain the critical balance between an immunogenic and tolerogenic immune response, in an immunospecialized location like the central nervous system (CNS). In this paper we looked at the anti-inflammatory properties of Apigenin in restoration of immune function and the resultant decrease in neuroinflammation. In vivo, a significant reduction in severity of experimental autoimmune encephalomyelitis (EAE) progression and relapse was observed in C57BL/6 (progressive) and SJL/J (relapse-remitting) mouse models of multiple sclerosis upon treatment with Apigenin. Apigenin treated EAE mice show decreased expression of α4 integrin and CLEC12A on splenic DCs and an increased retention of immune cells in the periphery compared to untreated EAE mice. This correlated consequently with immunohistochemistry findings of decreased immune cell infiltration and reduced demyelination in the CNS. These results indicate a protective role of Apigenin against the neurodegenerative effects resulting from the entry of DC stimulated pathogenic T cells into the CNS thus implicating a potential therapy for neuroinflammatory disease.

Alemtuzumab for the treatment of relapsing-remitting multiple sclerosis

Alemtuzumab, a humanized monoclonal antibody that targets CD52, was recently approved in the EU and Canada for the treatment of patients with active relapsing-remitting multiple sclerosis. Alemtuzumab induces rapid depletion of circulating B- and T-lymphocytes followed by repopulation that leads to a distinctive lymphocyte profile, including an increased proportion of regulatory T-lymphocytes and memory B- and T-lymphocytes. In early open-label studies, alemtuzumab treatment reduced the number of clinical relapses and new MRI lesions in participants with secondary progressive MS. However, most participants had continued worsening of disability, which led to the evaluation of alemtuzumab in patients with early stages of disease in the Genzyme (MA, USA)-sponsored clinical development program in MS. In one Phase II and two Phase III trials, alemtuzumab reduced the number of clinical relapses versus the active comparator, subcutaneous IFN-β-1a, in treatment-naive and treatment-experienced participants with relapsing-remitting multiple sclerosis. Two of these trials showed reduction in risk of confirmed worsening of disability, and all showed reduction in cerebral atrophy. Safety issues include infusion reactions that are mitigated by pretreatment with corticosteroids in addition to symptomatic management with antihistamines; mild to moderate infections; and autoimmune adverse events. In this context, post-marketing risk mitigation strategies will be needed so that potential adverse events can be identified and managed early and effectively.

Comparative efficacy of alemtuzumab and established treatment in the management of multiple sclerosis

Alemtuzumab is the newest disease-modifying therapy approved for the treatment of relapsing multiple sclerosis. Alemtuzumab is an anti-CD52 targeted antibody that causes lysis of T and B lymphocytes, monocytes, natural killer cells, macrophages, and dendritic cells. Following its administration, a prolonged T-cell lymphopenia results with emergence of a reconstituted immune system that differs in its composition from that pretreatment. In clinical trials, alemtuzumab has shown impressive efficacy with regard to clinical and radiological outcomes in relapsing multiple sclerosis, along with sustained long-term beneficial effects, and it is attractive for its once-yearly administration. Despite this, the occurrence of serious secondary autoimmune disorders, infections, and a potential risk of malignancy necessitates a careful evaluation of risks versus benefits for an individual patient prior to its use. The requirement of patient commitment to the intense mandatory monitoring program is also a factor to be considered when incorporating alemtuzumab into the treatment regimen.

The therapeutic potential of interleukin-10 in neuroimmune diseases

Neuroimmune diseases have diverse symptoms and etiologies but all involve pathological inflammation that affects normal central nervous system signaling. Critically, many neuroimmune diseases also involve insufficient signaling/bioavailability of interleukin-10 (IL-10). IL-10 is a potent anti-inflammatory cytokine released by immune cells and glia, which drives the regulation of a variety of anti-inflammatory processes. This review will focus on the signaling pathways and function of IL-10, the current evidence for insufficiencies in IL-10 signaling/bioavailability in neuroimmune diseases, as well as the implications for IL-10-based therapies to treating such problems. We will review in detail four pathologies as examples of the common etiologies of such disease states, namely neuropathic pain (nerve trauma), osteoarthritis (peripheral inflammation), Parkinson's disease (neurodegeneration), and multiple sclerosis (autoimmune). A number of methods to increase IL-10 have been developed (e.g. protein administration, viral vectors, naked plasmid DNA, plasmid DNA packaged in polymers to enhance their uptake into target cells, and adenosine 2A agonists), which will also be discussed. In general, IL-10-based therapies have been effective at treating both the symptoms and pathology associated with various neuroimmune diseases, with more sophisticated gene therapy-based methods producing sustained therapeutic effects lasting for several months following a single injection. These exciting results have resulted in IL-10-targeted therapeutics being positioned for upcoming clinical trials for treating neuroimmune diseases, including neuropathic pain. Although further research is necessary to determine the full range of effects associated with IL-10-based therapy, evidence suggests IL-10 may be an invaluable target for the treatment of neuroimmune disease. This article is part of a Special Issue entitled 'Neuroimmunology and Synaptic Function'.

Teriflunomide, an immunomodulatory drug, exerts anticancer activity in triple negative breast cancer cells

Triple-negative breast cancer (TNBC) is defined as a group of primary breast cancers lacking expression of estrogen, progesterone, and human epidermal growth factor receptor-2 (HER-2) receptors, characterized by higher relapse rate and lower survival compared with other subtypes. Due to lack of identified targets and molecular heterogeneity, conventional chemotherapy is the only available option for treatment of TNBC, but non-discordant positive therapeutic efficacy could not be achieved. Here, we demonstrated that these TNBC cells were sensitive to teriflunomide, which was a well-known immunomodulatory drug for treatment of relapsing multiple sclerosis (MS). Potent anti-cancer effects in TNBC in vitro, including proliferation inhibition, cell cycle delay, cell apoptosis, and suppression of cell motility and invasiveness, could be achieved with this agent. Of note, we showed that multiple signals involved in TNBC proliferation, survival, migratory, and invasive potential were under regulation by teriflunomide. Among them, we identified down-regulation of growth factor receptors to abolish growth maintenance, suppression of c-Myc, and cyclin D1 to contribute to its anti-proliferative effect, modulation of components of cell cycle to induce S-phase arrest, degradation of Bcl-xL, and up-regulation of BAX via activation of MAPK pathway to induce apoptosis, and inhibition of epithelial-mesenchymal transition (EMT) process, matrix metalloproteinase-9 (MMP9) expression, and inactivation of Src/FAK to reduce TNBC migration and invasion. The results identified teriflunomide may be of therapeutic benefit for the more aggressive and difficult-to-treat breast cancer subtype, indicating the use of teriflunomide for clinical trials for treatment of TNBC patients.

Natalizumab: a review of its use in the management of relapsing-remitting multiple sclerosis

Natalizumab (Tysabri®) is a humanized monoclonal antibody against the α4 chain of integrins and was the first targeted therapy to be approved for the treatment of relapsing-remitting multiple sclerosis (RRMS). Natalizumab acts as a selective adhesion molecule antagonist, which binds very late antigen (VLA)-4 and inhibits the translocation of activated VLA-4-expressing leukocytes across the blood-brain barrier into the CNS. In a pivotal phase III clinical trial, natalizumab 300 mg intravenously every 4 weeks for 2 years in adults with RRMS significantly reduced the annualized relapse rate and the risk of sustained progression of disability compared with placebo, as well as significantly increasing the proportion of relapse-free patients at 1 and 2 years. Natalizumab also significantly reduced the number of T2-hyperintense, gadolinium-enhancing and T1-hypointense lesions on magnetic resonance imaging, and significantly reduced the volume of T2-hyperintense and T1-hypointense lesions compared with placebo. Natalizumab recipients generally experienced improved health-related quality of life at 1-2 years. Natalizumab was generally well tolerated in pivotal trials. The only adverse events that were more frequent with natalizumab monotherapy than with placebo were fatigue and allergic reactions. The main safety and tolerability issue with natalizumab is the incidence of progressive multifocal leukoencephalopathy (PML). As long as the risk of PML is managed effectively, natalizumab is a valuable therapeutic option for adults with highly active relapsing forms of multiple sclerosis.

Teriflunomide and its mechanism of action in multiple sclerosis

Treatment of multiple sclerosis (MS) is challenging: disease-modifying treatments (DMTs) must both limit unwanted immune responses associated with disease initiation and propagation (as T and B lymphocytes are critical cellular mediators in the pathophysiology of relapsing MS), and also have minimal adverse impact on normal protective immune responses. In this review, we summarize key preclinical and clinical data relating to the proposed mechanism of action of the recently approved DMT teriflunomide in MS. Teriflunomide selectively and reversibly inhibits dihydro-orotate dehydrogenase, a key mitochondrial enzyme in the de novo pyrimidine synthesis pathway, leading to a reduction in proliferation of activated T and B lymphocytes without causing cell death. Results from animal experiments modelling the immune activation implicated in MS demonstrate reductions in disease symptoms with teriflunomide treatment, accompanied by reduced central nervous system lymphocyte infiltration, reduced axonal loss, and preserved neurological functioning. In agreement with the results obtained in these model systems, phase 3 clinical trials of teriflunomide in patients with MS have consistently shown that teriflunomide provides a therapeutic benefit, and importantly, does not cause clinical immune suppression. Taken together, these data demonstrate how teriflunomide acts as a selective immune therapy for patients with MS.

Pharmacokinetic evaluation of fingolimod for the treatment of multiple sclerosis

INTRODUCTION

Fingolimod is a sphingosine 1-phosphate receptor modulator with a novel mechanism of action and the first oral drug approved for the treatment of relapsing forms of multiple sclerosis (MS). Fingolimod reduces relapses more effectively than intramuscular interferon β1a and delays disability progression. Associated safety risks are bradyarrhythmia and atrioventricular block following the initial dose, requiring monitoring.

AREAS COVERED

This article examines the characteristics of fingolimod, its pharmacokinetic properties and the efficacy and tolerability in MS. Information on the pharmacology and mechanisms of action is also provided.

EXPERT OPINION

Fingolimod is an effective therapy for relapsing forms of MS in a convenient oral dose. Fingolimod may target not only inflammation but potentially also neurodegeneration. Antagonizing astrocyte sphingosine signaling may help explain the reduction in cerebral atrophy observed in Phase III trials. Long-term data about the safety of fingolimod are needed.

Targeting S1P1 receptor protects against murine immunological hepatic injury through myeloid-derived suppressor cells

Although FTY720 may alter migration and homing of lymphocytes via sphingosine-1-phosphate (S1P) receptors, our recent studies indicated that FTY720 directly controls the differentiation of Th1 cells to regulatory T cells (Tregs) by targeting S1P1. However, the pharmacological function of FTY720 in immunological hepatic injury remains unknown. In this study, the role and regulatory signaling pathway of S1P receptor were investigated using a pharmacological approach in immune-mediated hepatic injury (IMH). In the context of IMH, FTY720 significantly ameliorated mortality and hepatic pathology. In FTY720-treated mice, recruited CD11b(+)Gr1(+) myeloid-derived suppressor cells (MDSCs) mediate protection against IMH and are functional suppressive immune modulators that result in fewer IFN-γ-producing Th1 cells and more Foxp3(+) Tregs. In agreement, FTY720-treated MDSCs promote the reciprocal differentiation between Th1 cells and Tregs in vitro and in vivo. Mechanistically, FTY720 treatment induced inducible NO synthase expression and NO production in MDSCs. Pharmacologic inhibition of inducible NO synthase completely eliminates MDSC suppressive function and eradicates their inducible effects on T cell differentiation. Finally, the mTOR inhibitor, rapamycin, photocopies the effects of FTY720 on MDSCs, implicating mTOR as a downstream effector of S1P1 signaling. This study identifies MDSCs as an essential component that provides protection against IMH following FTY720 or rapamycin treatment, validating the S1P1-mTOR signaling axis as a potential therapeutic target in hepatic injury.

Alemtuzumab in the treatment of multiple sclerosis

Alemtuzumab (formerly known as Campath-1H) has recently been approved by the European Medicines Agency for highly-active, relapsing-remitting multiple sclerosis (MS). The molecule targets the CD52 surface glycoprotein on certain T cells and B cells and is thought to exert its effect in MS through a “resetting” of the lymphocyte population. Approval was granted on the strength of two pivotal studies, Comparison of Alemtuzumab and Rebif® Efficacy in Multiple Sclerosis (CARE-MS)-1 in the first-line setting and CARE-MS-2 in patients who had failed first-line therapy. In both studies, alemtuzumab significantly reduced the relapse rate compared to the comparator, interferon beta-1a (44 μg) given subcutaneously three-times per week (Rebif®). In the first-line study, alemtuzumab was also found to significantly reduce the number of patients with sustained progression compared to interferon beta-1a therapy. Autoimmune disorders represent the major side effect of alemtuzumab therapy although they can be managed by careful monitoring and early treatment. Overall, alemtuzumab is likely to be a valuable addition to the neurologist’s armamentarium for the treatment of relapsing-remitting MS.

FTY720 (fingolimod) is a neuroprotective and disease-modifying agent in cellular and mouse models of Huntington disease

Huntington disease (HD) is a genetic neurodegenerative disorder for which there is currently no cure and no way to stop or even slow the brain changes it causes. In the present study, we aimed to investigate whether FTY720, the first approved oral therapy for multiple sclerosis, may be effective in HD models and eventually constitute an alternative therapeutic approach for the treatment of the disease. Here, we utilized preclinical target validation paradigms and examined the in vivo efficacy of chronic administration of FTY720 in R6/2 HD mouse model. Our findings indicate that FTY720 improved motor function, prolonged survival and reduced brain atrophy in R6/2 mice. The beneficial effect of FTY720 administration was associated with a significant strengthening of neuronal activity and connectivity and, with reduction of mutant huntingtin aggregates, and it was also paralleled by increased phosphorylation of mutant huntingtin at serine 13/16 residues that are predicted to attenuate protein toxicity.

Daclizumab, an IL-2 modulating antibody for treatment of multiple sclerosis

Daclizumab is a monoclonal antibody specific for the IL-2R α chain (CD25). Daclizumab has been observed to have multiple mechanisms of action, which may contribute to beneficial effects in immune-related disease and particularly in relapsing and remitting multiple sclerosis (RRMS). These include inhibition of activated immune cells, increase of regulatory natural killer cells, effects on dendritic cells, inhibition of innate lymphoid tissue inducer cells and altered responses involving IL-2 transpresentation. The antibody has shown considerable promise in open-label and early Phase II clinical trials when used as a monotherapy, or in combination with IFN-β. In recently completed randomized trials in RRMS, treatment with daclizumab monotherapy compared with placebo resulted in clinically meaningful and statistically significant reductions in relapses, active lesions on brain MRI and slowing of disability progression. A large Phase III trial in RRMS is ongoing.

Nrf2/ARE-mediated antioxidant actions of pro-electrophilic drugs

Living cells maintain a balance between oxidation and reduction, and perturbations of this redox balance are thought to contribute to various diseases. Recent attempts to regulate redox state have focused on electrophiles (EPs), which activate potent cellular defense systems against oxidative stress. One example of this approach is exemplified by carnosic acid (CA) and carnosol (CS), compounds that are found in the herb rosemary (Rosmarinus officinalis). Importantly, CA and CS themselves are not electrophilic, but in response to oxidation, become electrophilic, and then activate the Keap1/Nrf2/ARE (antioxidant-response element) transcription pathway to synthesize endogenous antioxidant "phase 2" enzymes. As a result of our efforts to develop these compounds as therapeutics for brain health, we have formulated two innovative criteria for drug development: the first concept is the use of pro-electrophilic drugs (PEDs) that are innocuous in and of themselves; and the second concept involves the use of compounds that are pathologically activated therapeutics (PATs);i.e., these small molecules are chemically converted to their active form by the very oxidative stress that they are designed to then combat. The chemical basis for PED and PAT drugs is embodied in the ortho- and para-hydroquinone electrophilic cores of the molecules, which are oxidized by the Cu(2+)/Cu(+) cycling system (or potentially by other transition metals). Importantly, this cycling pathway is under stringent regulation by the cell redox state. We propose that redox-dependent quinone formation is the predominant mechanism for formation of PED and PAT drugs from their precursor compounds. In fact, redox-dependent generation of the active form of drug from the "pro-form" distinguishes this therapeutic approach from traditional EPs such as curcumin, and results in a decrease in clinical side effects at therapeutic concentrations, e.g., lack of reaction with other thiols such as glutathione (GSH), which can result in lowering GSH and inducing oxidative stress in normal cells. We consider this pro-drug quality of PED/PAT compoundsto be a key factor for generating drugs to be used to combat neurodegenerative diseases that will be clinically tolerated. Given the contribution of oxidative stress to the pathology of multiple neurodegenerative diseases, the Keap1/Nrf2/ARE pathway represents a promising drug target for these PED/PAT agents.

Protocol to isolate a large amount of functional oligodendrocyte precursor cells from the cerebral cortex of adult mice and humans

During development, oligodendrocytes are generated from oligodendrocyte precursor cells (OPCs), a cell type that is a significant proportion of the total cells (3-8%) in the adult central nervous system (CNS) of both rodents and humans. Adult OPCs are responsible for the spontaneous remyelination that occurs in demyelinating diseases like Multiple Sclerosis (MS) and they constitute an interesting source of cells for regenerative therapy in such conditions. However, there is little data regarding the neurobiology of adult OPCs isolated from mice since an efficient method to isolate them has yet to be established. We have designed a protocol to obtain viable adult OPCs from the cerebral cortex of different mouse strains and we have compared its efficiency with other well-known methods. In addition, we show that this protocol is also useful to isolate functional OPCs from human brain biopsies. Using this method we can isolate primary cortical OPCs in sufficient quantities so as to be able to study their survival, maturation and function, and to facilitate an evaluation of their utility in myelin repair.

Review of laquinimod and its therapeutic potential in multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a chronic immunological disease of the central nervous system characterized by early inflammatory demyelination and subsequent neurodegeneration. Although major progress has occurred, MS is still an incurable disease. Further, parenteral application and/or safety issues of the currently licensed drugs are associated with low patient compliance. Thus, there remains an unmet need for the development of more effective and well-tolerated oral therapies for the treatment of MS. At this point in time, different oral available substances are under investigation and hold promise in the treatment of relapsing-remitting MS (RRMS).

AREAS COVERED

The physical, chemical and pharmacological properties of laquinimod , as well as its suggested mechanisms of action, clinical efficacy and side-effect profile are reviewed.

EXPERT OPINION

Laquinimod is a new orally administered synthetic drug designed as an immunomodulator. Its mechanisms of action are not yet fully elucidated. Studies in mice and humans revealed different mechanisms of action, including anti-inflammatory and neuroprotective effects. So far, Phase II and Phase III clinical trials have shown its efficacy on magnetic resonance imaging based measures of disease activity, annualized relapse rate and disability progression in RRMS patients. Current data suggest a relatively modest efficacy by measures of relapse rate and there seems to be no superiority in comparison to established disease-modifying agents in relapsing-remitting MS. Further studies are necessary to evaluate both neuroprotective efficacy and optimal dosage of laquinimod in more detail.

Myelin recovery in multiple sclerosis: the challenge of remyelination

Multiple sclerosis (MS) is the most common demyelinating and an autoimmune disease of the central nervous system characterized by immune-mediated myelin and axonal damage, and chronic axonal loss attributable to the absence of myelin sheaths. T cell subsets (Th1, Th2, Th17, CD8⁺, NKT, CD4⁺CD25⁺ T regulatory cells) and B cells are involved in this disorder, thus new MS therapies seek damage prevention by resetting multiple components of the immune system. The currently approved therapies are immunoregulatory and reduce the number and rate of lesion formation but are only partially effective. This review summarizes current understanding of the processes at issue: myelination, demyelination and remyelination—with emphasis upon myelin composition/architecture and oligodendrocyte maturation and differentiation. The translational options target oligodendrocyte protection and myelin repair in animal models and assess their relevance in human. Remyelination may be enhanced by signals that promote myelin formation and repair. The crucial question of why remyelination fails is approached is several ways by examining the role in remyelination of available MS medications and avenues being actively pursued to promote remyelination including: (i) cytokine-based immune-intervention (targeting calpain inhibition), (ii) antigen-based immunomodulation (targeting glycolipid-reactive iNKT cells and sphingoid mediated inflammation) and (iii) recombinant monoclonal antibodies-induced remyelination.