Emerging therapies for multiple sclerosis

Analysis of left ventricular function of the mouse heart during experimentally induced hyperthyroidism and recovery

Many of the clinical manifestations of hyperthyroidism are due to the ability of thyroid hormones to alter myocardial contractility and cardiovascular hemodynamics, leading to cardiovascular impairment. In contrast, recent studies highlight also the potential beneficial effects of thyroid hormone administration for clinical or preclinical treatment of different diseases such as atherosclerosis, obesity and diabetes or as a new therapeutic approach in demyelinating disorders. In these contexts and in the view of developing thyroid hormone-based therapeutic strategies, it is, however, important to analyze undesirable secondary effects on the heart. Animal models of experimentally induced hyperthyroidism therefore represent important tools for investigating and monitoring changes of cardiac function. In our present study we use high-field cardiac MRI to monitor and follow-up longitudinally the effects of prolonged thyroid hormone (triiodothyronine) administration focusing on murine left ventricular function. Using a 9.4 T small horizontal bore animal scanner, cinematographic MRI was used to analyze changes in ejection fraction, wall thickening, systolic index and fractional shortening. Cardiac MRI investigations were performed after sustained cycles of triiodothyronine administration and treatment arrest in adolescent (8 week old) and adult (24 week old) female C57Bl/6 N mice. Triiodothyronine supplementation of 3 weeks led to an impairment of cardiac performance with a decline in ejection fraction, wall thickening, systolic index and fractional shortening in both age groups but with a higher extent in the group of adolescent mice. However, after a hormonal treatment cessation of 3 weeks, only young mice are able to partly restore cardiac performance in contrast to adult mice lacking this recovery potential and therefore indicating a presence of chronically developed heart pathology.

Immunohistochemistry analysis of bone marrow biopsies in multiple sclerosis patients undergoing autologous haematopoietic stem cells transplantation

OBJECTIVE

Recently autologous haematopoietic stem cell transplantation (AHSCT) has been introduced for the treatment of severe forms of multiple sclerosis (MS). As little data are available on bone marrow (BM) of MS patients undergoing AHSCT, we investigated the morphological and phenotypic characteristics of MS BM.

METHODS

BM biopsies of 14 MS patients screened for AHSCT and 10 control patients were evaluated to assess cellularity, morphology, immunological profile and bone marrow microenvironment. Immunohistochemistry analysis was performed to evaluate the expression of CD3, CD4, CD8, CD20, CD68, CD45, MMP-9.

RESULTS

8 out of 14 MS (57%) patients showed a reduction of age-related bone marrow cellularity, possibly due to previous immunosuppressive therapies. There were no differences in the T CD3+ lymphocyte expression rate amongst MS and the control patients, the CD4/CD8 ratio (2:1) was maintained as was the rate of B lymphocytes. We found an increased, although not significant, MMP-9 expression (9.2%) in the bone marrow of MS patients, when compared to the control patients (6.3%).

CONCLUSION

The BM of MS patients showed a reduced cellularity and CD45+ cells content in comparison to the controls. A slightly increased expression of MMP-9 was also shown, possibly confirming an involvement of this compartment in the pathogenesis of the disease.

A prospective, randomized, controlled trial of autologous haematopoietic stem cell transplantation for aggressive multiple sclerosis: a position paper

Background:

Haematopoietic stem cell transplantation (HSCT) has been tried in the last 15 years as a therapeutic option in patients with poor-prognosis autoimmune disease who do not respond to conventional treatments. Worldwide, more than 600 patients with multiple sclerosis (MS) have been treated with HSCT, most of them having been recruited in small, single-centre, phase 1–2 uncontrolled trials. Clinical and magnetic resonance imaging outcomes from case series reports or Registry-based analyses suggest that a major response is achieved in most patients; quality and duration of response are better in patients transplanted during the relapsing–remitting phase than in those in the secondary progressive stage.

Objectives:

An interdisciplinary group of neurologists and haematologists has been formed, following two international meetings supported by the European and American Blood and Marrow Transplantation Societies, for the purpose of discussing a controlled clinical trial, to be designed within the new scenarios of evolving MS treatments.

Conclusions:

Objectives of the trial, patient selection, transplant technology and outcome assessment were extensively discussed. The outcome of this process is summarized in the present paper, with the goal of establishing the background and advancing the development of a prospective, randomized, controlled multicentre trial to assess the clinical efficacy of HSCT for the treatment of highly active MS.

A transcription factor map as revealed by a genome-wide gene expression analysis of whole-blood mRNA transcriptome in multiple sclerosis

Background

Several lines of evidence suggest that transcription factors are involved in the pathogenesis of Multiple Sclerosis (MS) but complete mapping of the whole network has been elusive. One of the reasons is that there are several clinical subtypes of MS and transcription factors that may be involved in one subtype may not be in others. We investigate the possibility that this network could be mapped using microarray technologies and contemporary bioinformatics methods on a dataset derived from whole blood in 99 untreated MS patients (36 Relapse Remitting MS, 43 Primary Progressive MS, and 20 Secondary Progressive MS) and 45 age-matched healthy controls.

Methodology/Principal Findings

We have used two different analytical methodologies: a non-standard differential expression analysis and a differential co-expression analysis, which have converged on a significant number of regulatory motifs that are statistically overrepresented in genes that are either differentially expressed (or differentially co-expressed) in cases and controls (e.g., V$KROX_Q6, p-value <3.31E-6; V$CREBP1_Q2, p-value <9.93E-6, V$YY1_02, p-value <1.65E-5).

Conclusions/Significance

Our analysis uncovered a network of transcription factors that potentially dysregulate several genes in MS or one or more of its disease subtypes. The most significant transcription factor motifs were for the Early Growth Response EGR/KROX family, ATF2, YY1 (Yin and Yang 1), E2F-1/DP-1 and E2F-4/DP-2 heterodimers, SOX5, and CREB and ATF families. These transcription factors are involved in early T-lymphocyte specification and commitment as well as in oligodendrocyte dedifferentiation and development, both pathways that have significant biological plausibility in MS causation.

Risks vs benefits of glatiramer acetate: a changing perspective as new therapies emerge for multiple sclerosis

An understanding of the risks, benefits, and relative value of glatiramer acetate (GA) in multiple sclerosis (MS) has been evolving based on recently completed head-to-head studies: REGARD (REbif vs Glatiramer Acetate in Relapsing MS Disease); BEYOND (Betaseron Efficacy Yielding Outcomes of a New Dose); and BECOME (BEtaseron vs COpaxone in Multiple Sclerosis with Triple-Dose Gadolinium and 3-Tesla MRI Endpoints). Outcomes in the primary endpoints of these trials showed no significant differences between GA and high-dose beta-interferons (IFNβs). Results of the PreCISe (Early GA Treatment in Delaying Conversion to Clinically Definite Multiple Sclerosis [CDMS] in Subjects Presenting With a Clinically Isolated Syndrome [CIS]) trial led to the US Food and Drug Administration approval of GA in patients with a CIS. Furthermore, the ongoing follow-up study to the original pivotal GA trial, now extending beyond 15 years, continues to support the safety of GA. Currently, GA and IFNβs are no longer the only immunomodulators available for MS. Introduction of the monoclonal antibody, natalizumab (Tysabri^®; Biogen Idec, Inc., Cambridge, MA, USA) provides an alternative immunomodulator for MS and has changed the therapeutic landscape dramatically. However, the rare but serious cases of progressive multifocal leukoencephalopathy that have occurred with natalizumab have raised concerns among clinicians and patients about using this agent and some of the emerging agents. The potential risks and benefits of the emerging therapies (cladribine, alemtuzumab, rituximab, fingolimod, laquinimod, teriflunomide, and dimethyl fumarate) based on phase II/III trials, as well as their use for indications other than MS, will be presented. This review provides available data on GA, natalizumab, and the emerging agents to support new developments in our understanding of GA and how its long-standing role as a first-line therapy in MS will evolve within the increasingly complex MS therapeutic landscape.

FTY720 ameliorates MOG-induced experimental autoimmune encephalomyelitis by suppressing both cellular and humoral immune responses

FTY720, an oral sphingosine 1-phosphate (S1P) receptor modulator, has shown efficacy in phase II trials in patients with relapsing-remitting multiple sclerosis (MS). Although this molecule is thought to immunosuppress by inhibiting lymphocyte egress from the lymph nodes, the full spectrum of FTY720's actions has not yet been uncovered. In this study, we investigated the effects of FTY720 treatment on disease severity and histopathology of MOG-induced experimental autoimmune encephalomyelitis (EAE) in the dark agouti (DA) rat, a model that closely mimics several features of MS. The effects of FTY720 on T-cell subsets, anti-MOG antibody production, and mRNA expression of a number of cytokines and other genes were also examined. Commencement of treatment before disease onset prevented the appearance of clinical disease. Therapeutic treatment after established disease reduced clinical scores and substantially attenuated inflammation, demyelination, and axon loss. EAE suppression was associated with a reduction in all measured T-cell subsets in blood and spleen and a significant decrease in serum IgG(2a) levels. However, in the lymph nodes, all T-cell subsets except for naïve T cells and recent thymic emigrants remained unaffected. In addition, FTY720 treatment led to a significant inhibition in interferon-gamma, inducible nitric oxide synthase, and glial cell line-derived neurotrophic factor mRNA expression in the MOG-EAE spinal cord. In conclusion, our findings indicate that FTY720-mediated S1P receptor modulation ameliorates chronic relapsing MOG-EAE by suppressing both cellular and humoral immune responses.

Monoclonal antibodies in MS: mechanisms of action

The development of monoclonal antibodies (mAbs) presents an emerging, highly specific therapeutic strategy for the treatment of multiple sclerosis (MS). mAbs target selective molecules and have shown early promise, along with notable risks, in the treatment of MS and other immune-mediated diseases. The mechanism of action of the 4 mAbs under active investigation for MS (natalizumab, rituximab, alemtuzumab, and daclizumab) are reviewed, with a discussion of how mAb interaction with each target antigen may produce direct and indirect effects (proven and hypothesized) on immune cell activity, CNS-related inflammatory processes, and clinical outcomes.

Back to the future for multiple sclerosis therapy: focus on current and emerging disease-modifying therapeutic strategies

The last decade has seen numerous advances in the treatment of multiple sclerosis with six immunotherapeutic agents licensed for use. Although these therapeutic agents have powerful effects upon the inflammatory phase of disease, they have limitations in treating the progression of disability and in their safety profile. This review focuses on our current understanding of first- and second-line treatments for multiple sclerosis, including combination therapies, and also discusses the most promising novel therapeutic strategies on the horizon. Such agents include orally administered immunosuppressive drugs, monoclonal antibodies, antigen-specific tolerance, and neural protection and repair strategies. The challenge ahead lies in the delivery of potent drugs to inhibit inflammation and neurodegeneration while limiting side effects. Further elucidation of the pathophysiology of disease may provide new clinical targets and disease-relevant biomarkers that, in combination with proteomics, may help personalize treatment to individual patients.

Daclizumab treatment for multiple sclerosis

Multiple sclerosis is a chronic inflammatory and demyelinating disease of the central nervous system and the leading cause of neurologic disability in young adults. Established therapies, such as interferon and glatiramer, have only partial effects, and they offer limited or no effect on the progression of multiple sclerosis. The etiology of multiple sclerosis is unclear; however, the disease is presumed to be a T-cell-mediated autoimmune disease influenced by genetic and environmental factors. Therefore, targeting of lymphocytes may be a promising means of therapy for multiple sclerosis. Daclizumab is a humanized monoclonal antibody approved for use in preventing renal allograft rejection. The agent is under investigation in phase II trials for the treatment of multiple sclerosis and has demonstrated positive clinical outcomes, including decreased relapse rates. Adverse events included urinary tract infections, respiratory tract infections, paresthesias, mild leukopenia, transient elevations in liver enzyme and bilirubin levels, rash, postinfusion reactions (fever), lymphadenopathy, transient thrombocytopenia, and nausea. Daclizumab may be an alternative or add-on therapy when conventional immunomodulators fail or when existing approved therapies cannot be used. Besides ongoing phase II trials, additional phase II or III trials are required to determine the extended benefits of the agent, as well as clinical outcomes.

BAFF is a biological response marker to IFN-beta treatment in multiple sclerosis

Multiple sclerosis (MS) is a complex autoimmune disease characterized by the destruction of the myelin sheath of neurons. Interferon beta (IFN-beta) is currently the major drug used to treat MS. Some patients fail to respond to this treatment, in some cases due to the development of neutralizing antibodies (NAb) to IFN-beta. We used microarray analysis and RT-PCR to measure gene expression in whole blood, 9-15 h postinjection, in patients with and without NAbs to IFN-beta. The canonical marker of biological response to IFN-beta, myxovirus resistance protein A, was upregulated in all NAb- patients while remaining unchanged in NAb+ patients. Genes functioning in immune response pathways were dominant in the set of differentially expressed genes: 73 immune response genes were identified as upregulated and 29 genes were identified as downregulated. B-cell activating factor (BAFF) is a strong candidate marker for biological and clinical response as well as for predisposition to NAb development. We demonstrate that it is responsive to IFN-beta in vitro and in vivo, and that its soluble form is elevated in serum from NAb- but not NAb+ patients. We conclude BAFF is a good biomarker for IFN-beta response, and requires further studies to determine its value as a marker for clinical response and NAb predisposition.

Autologous haematopoietic stem-cell transplantation in multiple sclerosis

Intense immunosuppression followed by autologous haematopoietic stem-cell transplantation has been assessed over the past few years as a possible new therapeutic strategy in severe forms of multiple sclerosis. Pioneering studies began in 1995, and since then, more than 400 patients worldwide have been treated with this procedure. Small uncontrolled studies show that about 60-70% of treated cases do not progress in the follow-up period of at least 3 years. Transplant-related mortality, which was 5-6% in the first reported series, has reduced in the past 5 years to 1-2%. Relapses dramatically decrease and inflammatory MRI activity is almost completely suppressed. Autologous haematopoietic stem-cell transplantation is associated with qualitative immunological changes in the blood, suggesting that, beyond its immunosuppressive potential, it could also have some beneficial effect for the resetting of the immune system. Patients with severe, rapidly worsening multiple sclerosis who are unresponsive to approved therapies could be candidates for this treatment, but its clinical efficacy has still to be shown in large, prospective, controlled studies.

Translation towards personalized medicine in Multiple Sclerosis

In recent years the realization that the concept 'one drug fits all' - does not work, created the need to shift gears from 'treating the disease' to 'treating the patient', and implementation of 'Personalized Medicine' where treatment is tailored to the individual. In chronic and progressive diseases, such as Multiple Sclerosis (MS), the need for tailored therapeutics is especially imperative, as the consequences of an ineffective medication might be irreversible dysfunction. In recent years accumulating evidence indicates that MS is not a single disease and that patients with different disease subtypes respond differently to a medication. Environment and genetics are among the factors that determine disease subtype and activity, and the patient's response to medication. Additional factors include demographic characteristics such as gender and age, as well as chrono-biological indicators. During the last few years, advances and availability of new technologies have brought genome-wide gene expression profiling studies to many medical fields, including MS. Genomic technologies have also stimulated pharmacogenetics studies, that aim to identify genetic factors that affect response to treatment. However, pharmacogenetics information is still immature to allow its translation to clinical practice in MS. Notably, one of the major limitations in obtaining reproducible data across MS pharmacogenetics studies has been the lack of a consensus as to the appropriate method for determining clinical response. In light of the rapid advances in technology and progress in applying individualized treatment strategies in other diseases, 'Personalized Medicine' for MS seems feasible within the coming years.

Diagnosis and treatment of multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system that usually has onset between 20 and 40 years of age. The causes of MS are unknown, but it probably evolves among genetically susceptible individuals as an infrequent response to environmental factors. The diagnosis is based on careful evaluation of the disease history, clinical examination as well as paraclinical examination, aiming to document disseminated disease in both time and space. No cure is available, but corticosteroids can be used for relapses, various symptomatic treatments exist, and several long-term, disease-modifying therapies are available. This article reviews the diagnosis and treatment of MS, focusing on treatment of relapses and disease-modifying therapies.