Molecular pharmacodynamics of new oral drugs used in the treatment of multiple sclerosis

Alopecia associated with dimethyl fumarate treatment for multiple sclerosis

After 2 weeks of treatment, a woman with multiple sclerosis treated with dimethyl fumarate developed alopecia. Considering the adverse events, the therapy was discontinued, leading to alopecia regression during the next 3 months. Although the precise mechanism has not been completely elucidated, glutathione depletion or downregulation of aerobic glycolysis are considered to be potential reasons for hair loss induction. The incidence and mechanism of this uncommon adverse reaction to dimethyl fumarate should be further investigated.

Sphingosine-1-Phosphate Signaling in Ischemic Stroke: From Bench to Bedside and Beyond

Sphingosine-1-phosphate (S1P) signaling is being increasingly recognized as a strong modulator of immune cell migration and endothelial function. Fingolimod and other S1P modulators in ischemic stroke treatment have shown promise in emerging experimental models and small-scale clinical trials. In this article, we will review the current knowledge of the role of S1P signaling in brain ischemia from the aspects of inflammation and immune interventions, sustaining endothelial functions, regulation of blood-brain barrier integrity, and functional recovery. We will then discuss the current and future therapeutic perspectives of targeting S1P for the treatment of ischemic stroke. Mechanism studies would help to bridge the gap between preclinical studies and clinical practice. Future success of bench-to-bedside translation shall be based on in depth understanding of S1P signaling during stroke and on the ability to have a fine temporal and spatial regulation of the signal pathway.

Effectiveness and safety of dimethyl fumarate in progressive multiple sclerosis

Background

There is limited data analyzing the safety and effectiveness of dimethyl fumarate (DMF) in the progressive multiple sclerosis (PMS) population.

Objective

To analyze the safety and effectiveness of DMF in patients with PMS.

Methods

We used Cox proportional hazards models to compare the time to confirmed worsening and improvement on the Expanded Disability Status Scale (EDSS) and timed 25-foot walk (T25FW) between patients treated with DMF and glatiramer acetate (GA) for at least one year.

Results

We included 46 patients treated with DMF and 42 patients treated with GA. The safety and tolerability of GA and DMF were consistent with established profiles. There was no difference in confirmed EDSS progression. A trend towards reduced T25FW was seen in the DMF compared to GA after adjustment (HR = 0.86; 95% CI:0.37, 1.98; p = 0.72 and HR = 0.60; 95% CI:0.27, 1.34; p = 0.21, respectively).

Conclusion

Dimethyl fumarate showed a trend towards reduction in T25FW but no evidence of clinically significant impact on EDSS. The small sample precluded definitive determination.

Nitrated fatty acids: from diet to disease

Fatty acids not only provide caloric energy in our diets and building blocks of lipids but are also precursors of potent signaling molecules. Fatty acids can undergo enzymatic and non-enzymatic transformations to form autocrine and paracrine signaling molecules that regulate energy balance and metabolic homeostasis. A new class of lipid signaling mediators known as nitro-fatty acids (NO₂-FAs) has recently been identified. These NO₂-FAs are generated endogenously through non-enzymatic reactions of secondary products of nitrite and nitric oxide and are readily detected in human plasma and urine. NO₂-FAs are potent anti-inflammatory and antioxidant cell signaling mediators and exert protective effects in numerous pre-clinical animal models of disease including cardiovascular, pulmonary and renal fibrosis. Chronic unresolved inflammation is common key feature underlying most fibrotic disorders. Two pathways that converge on inflammation and oxidative stress are nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and nuclear factor kappa B (NF-κB). NO₂-FAs are pleiotropic signaling modulators that target both of these pathways providing a therapeutic strategy directed towards an integrated decrease in inflammation. This review summarizes the latest findings and understanding of the formation, signaling and anti-fibrotic effects of NO₂-FA.

Experimental Autoimmune Encephalomyelitis (EAE)-Induced Elevated Expression of the E1 Isoform of Methyl CpG Binding Protein 2 (MeCP2E1): Implications in Multiple Sclerosis (MS)-Induced Neurological Disability and Associated Myelin Damage

Multiple sclerosis (MS) is a chronic neurological disease characterized by the destruction of central nervous system (CNS) myelin. At present, there is no cure for MS due to the inability to repair damaged myelin. Although the neurotrophin brain derived neurotrophic factor (BDNF) has a beneficial role in myelin repair, these effects may be hampered by the over-expression of a transcriptional repressor isoform of methyl CpG binding protein 2 (MeCP2) called MeCP2E1. We hypothesize that following experimental autoimmune encephalomyelitis (EAE)-induced myelin damage, the immune system induction of the pathogenic MeCP2E1 isoform hampers the myelin repair process by repressing BDNF expression. Using an EAE model of MS, we identify the temporal gene and protein expression changes of MeCP2E1, MeCP2E2 and BDNF. The expression changes of these key biological targets were then correlated with the temporal changes in neurological disability scores (NDS) over the entire disease course. Our results indicate that MeCP2E1 mRNA levels are elevated in EAE animals relative to naïve control (NC) and active control (AC) animals during all time points of disease progression. Our results suggest that the EAE-induced elevations in MeCP2E1 expression contribute to the repressed BDNF production in the spinal cord (SC). The sub-optimal levels of BDNF result in sustained NDS and associated myelin damage throughout the entire disease course. Conversely, we observed no significant differences in the expression patterns displayed for the MeCP2E2 isoform amongst our experimental groups. However, our results demonstrate that baseline protein expression ratios between the MeCP2E1 versus MeCP2E2 isoforms in the SC are higher than those identified within the dorsal root ganglia (DRG). Thus, the DRG represents a more conducive environment than that of the SC for BDNF production and transport to the CNS to assist in myelin repair. Henceforth, the sub-optimal BDNF levels we report in the SC may arise from the elevated MeCP2E1 vs. MeCP2E2 ratio in the SC that creates a more hostile environment thereby preventing local BDNF production. At the level of transcript, we demonstrate that EAE-induces the pathological enhanced expression of MeCP2E1 that contributes to enhanced NDS during the entire disease course. Thus, the pathological induction of the MeCP2E1 isoform contributes to the disruption of the normal homeostatic signaling equilibrium network that exists between cytokines, neurotrophins and chemokines that regulate the myelin repair process by repressing BDNF. Our research suggests that the elevated ratio of MeCP2E1 relative to MeCP2E2 may be a useful diagnostic marker that clinicians can utilize to determine the degree of neurological disability with associated myelin damage. The elevated MeCP2E1 vs. MeCP2E2 ratios (E1/E2) in the SC prevent BDNF from reaching optimal levels required for myelin repair. Thus, the lower E1/E2 ratios in the DRG, allow the DRG to serve as a weak secondary compensatory mechanism for enhanced production and delivery of BDNF to the SC to try to assist in myelin repair.

Nogo-A Antibodies for Progressive Multiple Sclerosis

Most of the current therapies, as well as many of the clinical trials, for multiple sclerosis (MS) target the inflammatory autoimmune processes, but less than 20% of all clinical trials investigate potential therapies for the chronic progressive disease stage of MS. The latter is responsible for the steadily increasing disability in many patients, and there is an urgent need for novel therapies that protect nervous system tissue and enhance axonal growth and/or remyelination. As outlined in this review, solid pre-clinical data suggest neutralization of the neurite outgrowth inhibitor Nogo-A as a potential new way to achieve both axonal and myelin repair. Several phase I clinical studies with anti-Nogo-A antibodies have been conducted in different disease paradigms including MS and spinal cord injury. Data from spinal cord injury and amyotrophic lateral sclerosis (ALS) trials accredit a good safety profile of high doses of anti-Nogo-A antibodies administered intravenously or intrathecally. An antibody against a Nogo receptor subunit, leucine rich repeat and immunoglobulin-like domain-containing protein 1 (LINGO-1), was recently shown to improve outcome in patients with acute optic neuritis in a phase II study. Nogo-A-suppressing antibodies could be novel drug candidates for the relapsing as well as the progressive MS disease stage. In this review, we summarize the available pre-clinical and clinical evidence on Nogo-A and elucidate the potential of Nogo-A-antibodies as a therapy for progressive MS.

[Monitoring of blood parameters under course-modified MS therapy : Substance-specific relevance and current recommendations for action]

With the approval of various substances for the immunotherapy of multiple sclerosis (MS), treatment possibilities have improved significantly over the last few years. Indeed, the choice of individually tailored preparations and treatment monitoring for the treating doctor is becoming increasingly more complex. This is particularly applicable for monitoring for a treatment-induced compromise of the immune system. The following article by members of the German Multiple Sclerosis Skills Network (KKNMS) and the task force "Provision Structures and Therapeutics" summarizes the practical recommendations for approved immunotherapy for mild to moderate and for (highly) active courses of MS. The focus is on elucidating the substance-specific relevance of particular laboratory parameters with regard to the mechanism of action and the side effects profile. To enable appropriate action to be taken in clinical practice, any blood work changes that can be expected, in addition to any undesirable laboratory findings and their causes and relevance, should be elucidated.

Sphingosine 1-phosphate receptor modulation suppresses pathogenic astrocyte activation and chronic progressive CNS inflammation

Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating disease of the CNS that causes disability in young adults as a result of the irreversible accumulation of neurological deficits. Although there are potent disease-modifying agents for its initial relapsing-remitting phase, these therapies show limited efficacy in secondary progressive MS (SPMS). Thus, there is an unmet clinical need for the identification of disease mechanisms and potential therapeutic approaches for SPMS. Here, we show that the sphingosine 1-phosphate receptor (S1PR) modulator fingolimod (FTY720) ameliorated chronic progressive experimental autoimmune encephalomyelitis in nonobese diabetic mice, an experimental model that resembles several aspects of SPMS, including neurodegeneration and disease progression driven by the innate immune response in the CNS. Indeed, S1PR modulation by FTY720 in murine and human astrocytes suppressed neurodegeneration-promoting mechanisms mediated by astrocytes, microglia, and CNS-infiltrating proinflammatory monocytes. Genome-wide studies showed that FTY720 suppresses transcriptional programs associated with the promotion of disease progression by astrocytes. The study of the molecular mechanisms controlling these transcriptional modules may open new avenues for the development of therapeutic strategies for progressive MS.

From Leflunomide to Teriflunomide: Drug Development and Immunosuppressive Oral Drugs in the Treatment of Multiple Sclerosis

BACKGROUND

Immunosuppressive drugs have been used in the treatment of multiple sclerosis (MS) for a long time. Today, orally available second generation immunosuppressive agents have been approved or are filed for licensing as MS therapeutics. Due to semi-selective targeting of cellular processes, these second-generation immunosuppressive compounds might rather be immunomodulatory. For example, Teriflunomide inhibits the de novo pyrimidine synthesis and thus only targets rapidly proliferating cells, including lymphocytes. It is used as first line disease modifying therapy (DMT) in relapsing-remitting MS (RRMS).

METHODS

Review of online content related to oral immunosuppressants in MS with an emphasis on Teriflunomide.

RESULTS

Teriflunomide and Cladribine are second-generation immunosuppressants that are efficient in the treatment of MS patients. For Teriflunomide, a daily dose of 14 mg reduces the annualized relapse rate (ARR) by more than 30% and disability progression by 30% compared to placebo. Cladribine reduces the ARR by about 50% compared to placebo but has not yet been licensed due to unresolved safety concerns. We also discuss the significance of older immunosuppressive compounds including Azathioprine, Mycophenolate mofetile, and Cyclophosphamide in current MS therapy.

CONCLUSION

Teriflunomide has shown a favorable safety and efficacy profile in RRMS and is a therapeutic option for a distinct group of adult patients with RRMS.

Inflammation, Iron, Energy Failure, and Oxidative Stress in the Pathogenesis of Multiple Sclerosis

Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system. Different trigger pathologies have been suggested by the primary cytodegenerative “inside-out” and primary inflammation-driven “outside-in” hypotheses. Recent data indicate that mitochondrial injury and subsequent energy failure are key factors in the induction of demyelination and neurodegeneration. The brain weighs only a few percent of the body mass but accounts for approximately 20% of the total basal oxygen consumption of mitochondria. Oxidative stress induces mitochondrial injury in patients with multiple sclerosis and energy failure in the central nervous system of susceptible individuals. The interconnected mechanisms responsible for free radical production in patients with multiple sclerosis are as follows: (i) inflammation-induced production of free radicals by activated immune cells, (ii) liberation of iron from the myelin sheets during demyelination, and (iii) mitochondrial injury and thus energy failure-related free radical production. In the present review, the different sources of oxidative stress and their relationships to patients with multiple sclerosis considering tissue injury mechanisms and clinical aspects have been discussed.

Antidepressant activity of fingolimod in mice

Recent findings indicate that fingolimod, the first oral drug approved for the treatment of multiple sclerosis (MS), acts as a direct inhibitor of histone deacetylases (HDACs) and enhances the production of brain-derived neurotrophic factor (BDNF) in the CNS. Both mechanisms are relevant to the pathophysiology and treatment of major depression. We examined the antidepressant activity of fingolimod in mice subjected to chronic unpredictable stress (CUS), a model of reactive depression endowed with face and pharmacological validity. Chronic treatment with fingolimod (3 mg kg(-1), i.p., once a day for 4 weeks) reduced the immobility time in the forced swim test (FST) in a large proportion of CUS mice. This treatment also caused anxiogenic-like effects in the social interaction test without affecting anxiety-like behavior in the elevated plus maze or spatial learning in the water maze. CUS mice showed reduced BDNF levels and enhanced HDAC2 levels in the hippocampus. These changes were reversed by fingolimod exclusively in mice that showed a behavioral response to the drug in the FST. Fingolimod treatment also enhanced H3 histone K14-acetylation and adult neurogenesis in the hippocampus of CUS mice. Fingolimod did not affect most of the parameters we have tested in unstressed control mice. The antidepressant-like activity of fingolimod was confirmed in mice chronically treated with corticosterone. These findings show for the first time that fingolimod exerts antidepressant-like effect acting in a "disease-dependent" manner, and raise the interesting possibility that the drug could relieve depressive symptoms in MS patients independently of its disease-modifying effect on MS.

Visual detection of glial cell line-derived neurotrophic factor based on a molecular translator and isothermal strand-displacement polymerization reaction

Background

Glial cell line-derived neurotrophic factor (GDNF) is a small protein that potently promotes the survival of many types of neurons. Detection of GDNF is vital to monitoring the survival of sympathetic and sensory neurons. However, the specific method for GDNF detection is also un-discovered. The purpose of this study is to explore the method for protein detection of GDNF.

Methods

A novel visual detection method based on a molecular translator and isothermal strand-displacement polymerization reaction (ISDPR) has been proposed for the detection of GDNF. In this study, a molecular translator was employed to convert the input protein to output deoxyribonucleic acid signal, which was further amplified by ISDPR. The product of ISDPR was detected by a lateral flow biosensor within 30 minutes.

Results

This novel visual detection method based on a molecular translator and ISDPR has very high sensitivity and selectivity, with a dynamic response ranging from 1 pg/mL to 10 ng/mL, and the detection limit was 1 pg/mL of GDNF.

Conclusion

This novel visual detection method exhibits high sensitivity and selectivity, which is very simple and universal for GDNF detection to help disease therapy in clinical practice.

Varicella-zoster virus infections in patients treated with fingolimod: risk assessment and consensus recommendations for management

IMPORTANCE

Varicella-zoster virus (VZV) infections increasingly are reported in patients with multiple sclerosis (MS) and constitute an area of significant concern, especially with the advent of more disease-modifying treatments in MS that affect T-cell-mediated immunity.

OBJECTIVE

To assess the incidence, risk factors, and clinical characteristics of VZV infections in fingolimod-treated patients and provide recommendations for prevention and management.

DESIGN, SETTING, AND PARTICIPANTS

Rates of VZV infections in fingolimod clinical trials are based on pooled data from the completed controlled phases 2 and 3 studies (3916 participants) and ongoing uncontrolled extension phases (3553 participants). Male and female patients aged 18 through 55 years (18-60 years for the phase 2 studies) and diagnosed as having relapsing-remitting MS were eligible to participate in these studies. In the postmarketing setting, reporting rates since 2010 were evaluated.

INTERVENTIONS

In clinical trials, patients received fingolimod at a dosage of 0.5 or 1.25 mg/d, interferon beta-1a, or placebo. In the postmarketing setting, all patients received fingolimod, 0.5 mg/d (total exposure of 54,000 patient-years at the time of analysis).

MAIN OUTCOMES AND MEASURES

Calculation of the incidence rate of VZV infection per 1000 patient-years was based on the reporting of adverse events in the trials and the postmarketing setting.

RESULTS

Overall, in clinical trials, VZV rates of infection were low but higher with fingolimod compared with placebo (11 vs 6 per 1000 patient-years). A similar rate was confirmed in the ongoing extension studies. Rates reported in the postmarketing settings were comparable (7 per 1000 patient-years) and remained stable over time. Disproportionality in reporting herpes zoster infection was higher for patients receiving fingolimod compared with those receiving other disease-modifying treatments (empirical Bayes geometric mean, 2.57 [90% CI, 2.26-2.91]); the proportion of serious herpes zoster infections was not higher than the proportion for other treatments (empirical Bayes geometric mean, 1.88 [90% CI, 0.87-3.70]). Corticosteroid treatment for relapses might be a risk factor for VZV reactivation.

CONCLUSIONS AND RELEVANCE

Rates of VZV infections in clinical trials were low with fingolimod, 0.5 mg/d, but higher than in placebo recipients. Rates reported in the postmarketing setting are comparable. We found no sign of risk accumulation with longer exposure. Serious or complicated cases of herpes zoster were uncommon. We recommend establishing the patient's VZV immune status before initiating fingolimod therapy and immunization for patients susceptible to primary VZV infection. Routine antiviral prophylaxis is not needed, but using concomitant pulsed corticosteroid therapy beyond 3 to 5 days requires an individual risk-benefit assessment. Vigilance to identify early VZV symptoms is important to allow timely antiviral treatment.