What do we know about the mechanism of action of disease-modifying treatments in MS?

Association of interleukin 6, interleukin 7 receptor alpha, and interleukin 12B gene polymorphisms with multiple sclerosis

Pro-inflammatory and anti-inflammatory cytokines have been shown to play a crucial role in the pathophysiology of multiple sclerosis (MS). We investigated the association between interleukin (IL) IL6-174 G/C (rs1800795), IL7RA C/T (rs6897932), and IL-12B A1188C (rs3212227) gene polymorphisms (SNPs) and MS. The study consisted of 297 unrelated MS patients and 135 healthy individuals. In IL6-174G/C (rs1800795), a significant association between the C allele and MS risk [OR 1.41, 95% CI (1.05-1.92); P = 0.025] was found. Carriage of genotypes CC and CG were more common in MS patients [OR 1.58, 95% CI (1.04-2.39); P = 0.031] and also in female MS patients [OR 1.68, 95% CI (1.02-2.79); P = 0.043]. However, after applying Bonferroni's correction the differences did not remain significant. No significant association between the IL7RA C/T (rs6897932) and IL12B A1188C (rs3212227) gene polymorphisms and MS susceptibility was observed. Regarding IL-12B A1188C (rs3212227), a significant association between the CC genotype and MS progression, expressed as MSSS, was demonstrated in the female MS group. Our results indicate that the distribution of IL6-174G/C (rs1800795) SNP was marginally associated with MS susceptibility. We also showed that IL-12B A1188C (rs3212227) can contribute to the progression of the disease in the Czech population.

Merits and complexities of modeling multiple sclerosis in non-human primates: implications for drug discovery

INTRODUCTION

The translation of scientific discoveries made in animal models into effective treatments for patients often fails, indicating that currently used disease models in preclinical research are insufficiently predictive for clinical success. An often-used model in the preclinical research of autoimmune neurological diseases, multiple sclerosis in particular, is experimental autoimmune encephalomyelitis (EAE). Most EAE models are based on genetically susceptible inbred/SPF mouse strains used at adolescent age (10-12 weeks), which lack exposure to genetic and microbial factors which shape the human immune system. Areas covered: Herein, the authors ask whether an EAE model in adult non-human primates from an outbred conventionally-housed colony could help bridge the translational gap between rodent EAE models and MS patients. Particularly, the authors discuss a novel and translationally relevant EAE model in common marmosets (Callithrix jacchus) that shares remarkable pathological similarity with MS. Expert opinion: The MS-like pathology in this model is caused by the interaction of effector memory T cells with B cells infected with the γ1-herpesvirus (CalHV3), both present in the pathogen-educated marmoset immune repertoire. The authors postulate that depletion of only the small subset (<0.05%) of CalHV3-infected B cells may be sufficient to limit chronic inflammatory demyelination.

Cognition and fatigue in patients with relapsing multiple sclerosis treated by subcutaneous interferon β-1a: an observational study SKORE

BACKGROUND

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system, which often causes progressive neurological disability. In addition to motor and sensory dysfunction, cognitive decline and fatigue are frequent manifestations of the disease. Fatigue is probably the most common symptom, with up to 90% of MS individuals reporting fatigue at some point. Cognitive impairment affects about 50% of patients and may be present at all MS stages. The aim of this observational study was to evaluate changes in cognition, fatigue, and disability status in 300 relapsing-remitting MS (RRMS) patients, treated with subcutaneous (sc) interferon (IFN) β-1a over 2 years.

METHODS

The study was designed as an observational, multicentre, prospective, single-arm, phase IV study carried out in 13 MS centres in the Czech Republic. Cognition status was assessed using the Paced Auditory Serial Addition Task (PASAT), fatigue using the Fatigue Descriptive Scale (FDS), and disability using the Expanded Disability Status Scale (EDSS), at baseline, and after 6, 12 and 24 months. The percentage of patients with changed versus stable cognition, fatigue status and disability was calculated at each time point and the changes in these scores were evaluated.

RESULTS

The proportion of patients with cognitive improvement was higher compared with those with a stable or decreased PASAT scores at all time points, and the average cognitive performance improved during the follow-up period. Also the proportion of patients with stable or improved fatigue and EDSS scores was higher compared with those in which FDS or EDSS scores declined, this was found at all time points of the analysed sample. However, the direct effect of IFN β-1a on cognition and fatigue cannot be concluded from this study.

CONCLUSIONS

The results of this observational study have demonstrated a stable or improved cognitive performance, fatigue status, and disability level in the majority of RRMS patients treated with sc IFN β-1a over a two-year follow-up period, in a real life setting, in the Czech Republic.

Multiple sclerosis: Association of gelatinase B/matrix metalloproteinase-9 with risk and clinical course the disease

BACKGROUND

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammation and axonal degeneration of the central nervous system and a leading cause of disability in young adults. The matrix metalloproteinases in general and specially gelatinase B/metalloproteinase-9 (MMP-9) plays a role in the pathogenesis of multiple sclerosis.

OBJECTIVE

To investigate the presence of the MMP-9 -1562C/T polymorphism in a Portuguese population of MS patients and assess its impact in susceptibility and course of the disease. The relation of MMP-9 serum levels with the polymorphism and with clinical and therapeutic factors will also be assessed.

METHODS

Our study included 355 Caucasian individuals distributed as MS patients (n=169) and controls (n=186). Samples were genotyped for -1562C/T polymorphism by PCR-RFLP analysis. MMP-9 concentration in serum was analyzed using a commercially available enzyme-linked immunosorbent assay.

RESULTS

A significant increase in T-allele frequency was found in female MS patients, but not in the total patient population. No association between the presence of the polymorphism and disease progression was found. MMP-9 serum concentrations were increased in patients, and although not influenced by the -1562C/T polymorphism, were modified by INF-beta therapy.

CONCLUSION

Although we did not find an association of this polymorphism with disease susceptibility or prognosis, MMP-9 appears to be a good therapeutic response marker for multiple sclerosis.

Effect of interferon-β1b on CXCR4-dependent chemotaxis in T cells from multiple sclerosis patients

Multiple sclerosis (MS) is an inflammatory, demyelinating and neurodegenerative disease triggered by infiltration of activated T cells into the central nervous system. Interferon (IFN)-β is an established, safe and effective treatment for patients with relapsing-remitting MS (RRMS). The cytokine can inhibit leucocyte infiltration into the central nervous system; however, little is known about the precise molecular mechanisms. Previously, in vitro application of IFN-β1b was shown to reduce CXCL12/CXCR4-mediated monocyte migration. Here, we analysed the effects of IFN-β1b on CXCR4-dependent T cell function. In vitro exposure to IFN-β1b (1000 U/ml) for 20 h reduced CXCR4-dependent chemotaxis of primary human T cells from healthy individuals and patients with RRMS. Investigating the IFN-β1b/CXCR4 signalling pathways, we found no difference in phosphorylation of ZAP70, ERK1/2 and AKT despite an early induction of the negative regulator of G-protein signalling, RGS1 by IFN-β1b. However, CXCR4 surface expression was reduced. Quantitative real time-PCR revealed a similar reduction in CXCR4-mRNA, and the requirement of several hours' exposure to IFN-β1b supports a transcriptional regulation. Interestingly, T cells from MS patients showed a lower CXCR4 expression than T cells from healthy controls, which was not reduced further in patients under IFN-β1b therapy. Furthermore, we observed no change in CXCL12-dependent chemotaxis in RRMS patients. Our results demonstrate clearly that IFN-β1b can impair the functional response to CXCR4 by down-regulating its expression, but also points to the complex in vivo effects of IFN-β1b therapy.

Treatment options to reduce disease activity after natalizumab: paradoxical effects of corticosteroids

AIM

Natalizumab (NTZ) discontinuation leads to multiple sclerosis (MS) recurrence, but represents the only known strategy to limit the risk of progressive multifocal leukoencephalopathy (PML) in JCV seropositive patients. Here, we compared the clinical and imaging features of three groups of patients who discontinued NTZ treatment.

METHODS

We treated 25 patients with subcutaneous INFβ-1b (INF group), 40 patients with glatiramer acetate (GA group), and 40 patients with GA plus pulse steroid (GA+CS group).

RESULTS

Six of 25 patients (24%) of the INF group were relapse-free 6 months after NTZ suspension. In GA group, a significant higher proportion of patients (26 of 40 patients, 65%) were relapse-free (P<0.05). Far from improving the clinical effects of GA in post-NTZ setting, combination of GA+CS was associated with lower relapse-free rate than GA alone (40% vs. 65%, P=0.04). Also on MRI parameters, combination of GA+CS was associated with worse outcome than GA alone, as 22 of 26 subjects (84.6%) had MRI evidence of disease activity 6 months after NTZ discontinuation.

CONCLUSION

Corticosteroids should not be used in combination with GA to prevent post-NTZ disease recurrence.

Dendritic cells in multiple sclerosis: key players in the immunopathogenesis, key players for new cellular immunotherapies?

Many studies have demonstrated the role of the adaptive immune system in the pathogenesis of multiple sclerosis (MS). Recent data suggest that dendritic cells (DCs), which are innate immune cells, also contribute to the pathogenesis of MS. In patients with MS, DCs are abundantly present in brain lesions, and display an altered phenotype and/or function as compared with this in healthy controls. DCs are thus in the position to pathologically influence the effector function of (auto-reactive) T and B cells. Interestingly, current first-line immunomodulating therapies for MS have been shown to restore DC phenotype and function, albeit in a non-specific manner. To date, clinical trials using agents specifically targeting DC function are ongoing. Moreover, several studies worldwide are currently investigating possible strategies to develop tolerogenic DCs. This review focuses on the phenotypic and functional alterations of conventional DCs and plasmacytoid DCs in patients with MS. Furthermore, we discuss how existing immunomodulating therapies for MS patients affect DC function and address future perspectives in the development of immunotherapies specifically targeting DCs.

Adrenergic and dopaminergic modulation of immunity in multiple sclerosis: teaching old drugs new tricks?

Multiple sclerosis (MS) is an autoimmune disorder of the CNS characterized by inflammation, demyelination and axonal loss. Classical evidence in experimental allergic encephalomyelitis, the animal model of MS, support the relevance of sympatoadrenergic as well as of dopaminergic mechanisms. In MS patients, dysregulation of adrenergic and dopaminergic pathways contribute to the disease in immune system cells as well as in glial cells. Available evidence is summarized and discussed also in the light of the novel role of dopamine, noradrenaline and adrenaline as transmitters in immune cells, providing a conceptual frame to exploit the potential of several dopaminergic and adrenergic agents, already in clinical use for non-immune indications and with a usually favourable risk-benefit profile, as add-on drugs to conventional immunomodulating therapies in MS.

Immunopathogenesis of multiple sclerosis: new insights and therapeutic implications

Multiple sclerosis (MS) is an inflammatory, demyelinating, and neurodegenerative disorder of the CNS. The etiology of MS remains unknown. However, it is well established that immune dysregulation plays a critical role in the neuropathogenesis of this disorder. In this review, we discuss the current hypotheses concerning the complex cellular and molecular interactions involved in the immunopathogenesis of MS. Although CD4 T lymphocytes have long been considered the critical cellular factor in the immunopathology of MS, the role of other cell types has also recently been investigated. It appears that the spatial distribution of CD4 and CD8 cells in MS lesions is distinct. Yet another T-lymphocyte subset, γ/δ T cells, can be detected in very early MS lesions. The prevalent dogma suggests that CD4 helper T (TH) type 1 cells release cytokines and inflammatory mediators that cause tissue damage, while CD4 TH2 cells might be involved in modulation of these effects. However, a mounting body of evidence suggests that additional T-cell subsets, including TH17 cells, CD8 effector T cells, and CD4 CD25 regulatory T cells, also affect disease activity. In addition, clinical and paraclinical data are accumulating on the prominent role of B lymphocytes and other antigen-presenting cells in MS neuropathogenesis. Given these observations, new therapeutic interventions for MS will need to focus on resetting multiple components of the immune system.

Interferon-β therapy against EAE is effective only when development of the disease depends on the NLRP3 inflammasome

Interferon-β (IFN-β) is widely used to treat multiple sclerosis (MS), and its efficacy was demonstrated in the setting of experimental autoimmune encephalomyelitis (EAE), an animal model of MS; however, IFN-β is not effective in treating all cases of MS. Here, we demonstrate that signaling by IFNAR (the shared receptor for IFN-α and IFN-β) on macrophages inhibits activation of Rac1 and the generation of reactive oxygen species (ROS) through suppressor of cytokine signaling 1 (SOCS1). The inhibition of Rac1 activation and ROS generation suppressed the activity of the Nod-like receptor (NLR) family, pyrin domain-containing 3 (NLRP3) inflammasome, which resulted in attenuated EAE pathogenicity. We further found that two subsets of EAE could be defined on the basis of their dependency on the NLRP3 inflammasome and that IFN-β was not an effective therapy when EAE was induced in an NLRP3 inflammasome-independent fashion. Thus, our study demonstrates a previously uncharacterized signaling pathway that is involved in the suppression of EAE by IFN-β and characterizes NLRP3-independent EAE, which cannot be treated with IFN-β.

Evaluation of serum levels of chemokines during interferon-β treatment in multiple sclerosis patients: a 1-year, observational cohort study

BACKGROUND

The molecules that provide access to activated T cells in the CNS, including chemokines, have been considered to be a crucial step in the pathogenesis of multiple sclerosis (MS).

AIMS

In this study, we investigated serial serum chemokine levels in patients with relapsing-remitting MS over 1 year and the association of these chemokine levels with treatment regimens, lesions on MRI and patients' characteristics.

METHODS

Serum CXCL9, CXCL10, CCL2, CCL4 and CCL5 levels were evaluated using ELISA every 2 months for a year in 28 healthy controls and 28 MS patients during their treatment with interferon (IFN)-β. Patients underwent MRI and were evaluated using the Expanded Disability Status Scale (EDSS) at the first and final evaluations.

RESULTS

CXCL10 serum levels were higher in MS patients compared with controls, were positively correlated with T2 lesions on MRI and were slightly increased during relapses. Treatment with IFNβ-1a or IFNβ-1b was associated with increased CXCL10 levels when evaluated more than 36 hours after subcutaneous injection. The CXCL9 levels were higher after MS relapse. There was significant variability in CCL4 and CCL5 levels in the serial evaluations, associated with gender and treatment. CCL2 levels were higher in treated MS patients than healthy controls, particularly among those patients with a stable form of the disease.

CONCLUSION

Serum is a feasible resource for searching for an immunological marker in MS. Peripheral chemokine levels correlated in different ways with IFNβ therapy and with disease and patient characteristics.

CLINICAL TRIAL REGISTRATION NUMBER

ISRCTN45526724.

Sieving treatment biomarkers from blood gene-expression profiles: a pharmacogenomic update on two types of multiple sclerosis therapy

Interferon-β (IFN-β) and glatiramer acetate are routinely used to inhibit disease activity in multiple sclerosis, but their mechanisms of action are incompletely understood. Individual treatment responses vary and candidate molecular markers that predict them have yet to be established. Why some patients respond poorly to a certain treatment while others respond well is addressed by the pharmacogenomic approach, which postulates that the molecular response to treatment correlates with the clinical effects, and thus seeks biological markers to estimate prognosis, guide therapy, comprehend the drugs' mechanisms of action and offer insights into disease pathogenesis. A poor clinical response can be owing to genetic variants in drug receptors or signaling components, or the appearance of neutralizing antibodies that interfere with the drug's binding efficacy. Independently, such mechanisms could lead to inadequate, that is to say unchanged, molecular responses, or exceedingly increased or decreased changes. By means of DNA microarray studies, various research groups endeavour to establish a clinically relevant relationship between the biological response to these drugs and treatment effects. Molecular profiles obtained in this way differ in the pattern and number of modulated genes, suggesting the existence of an individual 'drug-response fingerprint'. To further unravel the underlying regulatory interaction structure of the genes responsive to these immunotherapies represents a daunting but inevitable task. In this article, we focus on longitudinal ex vivo transcriptomic studies in multiple sclerosis and its therapy. We will discuss recurrently reported biomarker candidates, emphasizing those of immunologically meaning, and review studies with network module outputs.

PEGylated interferon beta-1a: meeting an unmet medical need in the treatment of relapsing multiple sclerosis

Multiple sclerosis is a chronic autoimmune disease of the central nervous system for which a number of disease-modifying therapies are available, including interferon beta (Avonex®, Rebif®, and Betaseron/Betaferon®), glatiramer acetate (Copaxone®), and an anti-VLA4 monoclonal antibody (Tysabri®). Despite the availability and efficacy of these protein and peptide drugs, there remains a significant number of patients who are untreated, including those with relatively mild disease who choose not to initiate therapy, those wary of injections or potential adverse events associated with therapy, and those who have stopped therapy due to perceived lack of efficacy. Since these drugs have side effects that may affect a patient's decision to initiate and to remain on treatment, there is a need to provide a therapy that is safe and efficacious but that requires a reduced dosing frequency and hence a concomitant reduction in the frequency of side effects. Here we describe the development of a PEGylated form of interferon beta-1a that is currently being tested in a multicenter, randomized, double-blind, parallel-group, placebo-controlled study in relapsing multiple sclerosis patients, with the aim of determining the safety and efficacy of 125 microg administered via the subcutaneous route every 2 or 4 weeks.

Update on inflammation, neurodegeneration, and immunoregulation in multiple sclerosis: therapeutic implications

Multiple sclerosis (MS) is an inflammatory, demyelinating, and neurodegenerative disease of the central nervous system of uncertain etiology. There is consensus that a dysregulated immune system plays a critical role in the pathogenesis of MS; therefore, we aim to summarize current hypotheses concerning the complex cellular and molecular interactions involved in the immunopathology of MS. Although CD4+ T lymphocytes have long been implicated in the immunopathology of MS, the role of other T-cell subtypes has been recognized. CD4+ and CD8+ cells have been isolated from different locations within MS lesions and gamma/delta T cells have been isolated from early MS lesions. The prevalent dogma has been that CD4+ TH1 cells release cytokines and mediators of inflammation that may cause tissue damage, although CD4+ TH2 cells may be involved in modulation of these effects. Recent evidence, however, suggests that additional T-cell subsets play a prominent role in MS immunopathology: TH17 cells, CD8+ effector T cells, and CD4+CD25+ regulatory T cells. In addition, laboratory and clinical data are accumulating on the prominent role of B lymphocytes and antigen-presenting cells in MS pathogenesis. On the basis of these observations, new therapeutic approaches for MS will need to focus on resetting multiple components of the immune system.

Glatiramer acetate improves regulatory T-cell function by expansion of naive CD4(+)CD25(+)FOXP3(+)CD31(+) T-cells in patients with multiple sclerosis

Naturally occurring regulatory T-cells (Treg) exhibit impaired function in patients with relapsing-remitting multiple sclerosis (RRMS) resulting from an age-inappropriate disproportion between prevalences of newly generated CD31-coexpressing naive Treg and long-lived memory Treg in the periphery. Recent evidence suggests that the immunomodulatory action of glatiramer acetate (GA) includes effects on Treg function and frequencies. We prospectively assessed suppressive activities and frequencies of Treg and Treg subsets in 15 patients with RRMS undergoing long-term therapy with GA. Treatment for up to six months reconstituted naive Treg and increased total Treg numbers with concomitant reversion of the Treg defect.

Matrix metalloproteinase-9 and matrix metalloproteinase-2 as biomarkers of various courses in multiple sclerosis

Background

Matrix metalloproteinases are notable contributors to neuroinflammation and blood-brain barrier disruption in multiple sclerosis (MS).

Objective

The goal of this study was to determine the serum levels of matrix metalloproteinase-9 (MMP-9), matrix metalloproteinase-2 (MMP-2), and their tissue inhibitors (TIMP-1) and (TIMP-2), and to investigate their possible relations to type, disability, and severity of MS.

Materials and methods

Eighty-seven patients with definite MS according to the McDonald criteria and 50 healthy controls were enrolled in the study. Their clinical status was evaluated with the Expanded Disability Status Scale. Serum levels were analyzed by enzyme-linked immunoassay.

Results

A significant elevation in MMP-9 serum levels and in the MMP-9/TIMP-1 ratio was found in the whole MS group ( P < 0.001), in the relapsing–remitting MS (RRMS) ( P < 0.001), and secondary-progressive MS (SPMS) ( P < 0.001) groups when compared with the controls. A significant elevation in MMP-2 serum levels and in the MMP-2/TIMP-2 ratio was observed in the primary progressive ( P < 0.001) and the SPMS ( P < 0.002) groups when compared with the RRMS group, and this increase was also associated with the disability ( P < 0.001) and severity ( P < 0.05) of the disease.

Conclusion

We confirmed that metalloproteinases are useful biological markers in MS, providing information about the clinical type, disability, and severity of the disease.

Therapy with interferon-beta modulates endogenous catecholamines in lymphocytes of patients with multiple sclerosis

OBJECTIVE

To investigate the endogenous dopaminergic/adrenergic system of lymphocytes in multiple sclerosis (MS) patients during treatment with interferon (IFN)-beta.

METHODS

Patients with relapsing-remitting MS undergoing IFN-beta treatment were prospectively studied during the first year of treatment. Circulating lymphocytes were obtained at baseline and after 1, 3, 6 and 12 months of treatment and assayed for catecholamine (CA) production and mRNA expression of tyrosine hydroxylase (TH, the rate-limiting enzyme in the synthesis of CA), beta(2)-adrenoceptors (AR) and D2, D3 and D5 dopaminergic receptors (DR).

RESULTS

In cells from patients treated with IFN-beta for 12 months the production of CA hugely increased and was less sensitive to IFN-gamma-induced inhibition. Expression of mRNA for TH, beta(2)-AR and DRD5 was already enhanced after 1 month and further increased up to 6-12 months of treatment. On the contrary, DRD2 mRNA progressively decreased and DRD3 mRNA did not significantly change over the whole study period.

CONCLUSIONS

In MS patients IFN-beta treatment enhances the ability of lymphocytes to produce CA, and induces extensive modifications of both beta(2)-AR and DR-operated pathways. The clinical relevance of these effects deserves consideration.

B-cell-targeted treatment for multiple sclerosis: mechanism of action and clinical data

Strategies for treating autoimmune disorders are increasingly employing targeted therapies rather than non-specific, multitargeted treatments. Accumulating evidence on the involvement of B lymphocytes in the pathophysiology of autoimmune demyelinating disease has led to a renewed interest in B cells as potential therapeutic targets. In particular, antigen presentation between B cells and T cells, increased trafficking of B cells across the blood-brain barrier, and autoantibodies produced by plasma cells may contribute to the pathophysiology of autoimmune disorders such as multiple sclerosis. Several B-cell-targeted, depletion therapies are currently in development, including rituximab, epratuzumab, diphtheria toxin-single chain Fv (DC2219), belimumab, atacicept, abatacept, and abetimus sodium. Of these agents, only rituximab and abatacept have been evaluated in multiple sclerosis patients. Preliminary results of a phase II trial of rituximab in multiple sclerosis suggest that rituximab is well tolerated and significantly reduces the number of gadolinium enhancing lesions over 24 weeks of treatment. Results of an exploratory analysis suggest the potential promise of abatacept 10 mg/kg for multiple sclerosis. It is expected that future clinical trials will establish a role for B-cell-targeted therapies in the treatment of multiple sclerosis and other autoimmune neurological diseases. This article describes the mechanism of action behind B-cell-targeted depletion therapies in development and reviews available clinical data.

Increased IL-10 mRNA and IL-23 mRNA expression in multiple sclerosis: interferon-beta treatment increases IL-10 mRNA expression while reducing IL-23 mRNA expression

BACKGROUND

Interferon (IFN)-beta therapy in multiple sclerosis (MS) has been suggested to promote a deviation from T lymphocyte production of pathogenic Th1 cytokines to less detrimental Th2 cytokines, but this is still controversial. We studied patterns of in vivo blood mononuclear cell (MNC) and whole blood cytokine and transcription factor mRNA expression before and during IFN-beta therapy in MS.

METHODS

Twenty patients with relapsing-remitting MS were sampled before and after 3 months of treatment with IFN-beta along with 15 healthy volunteers. An additional 39 patients and 50 healthy volunteers served to confirm initial findings. mRNA was analyzed by real-time reverse transcriptase polymerase chain reaction (PCR).

RESULTS

We found elevated expression of interleukin (IL)-23 and IL-10 in untreated MS patients. IFN-beta therapy increased IL-10 and decreased IL-23 expression independently of any Th1 or Th2 cytokines. The largest changes in cytokine mRNA levels occurred early (~9-12 h) after an IFN-beta injection.

CONCLUSION

We found no evidence of a Th1- or Th2-mRNA-promoting effect of IFN-beta therapy. The therapeutic effect of IFN-beta is more likely attributable to the induction of the regulatory cytokine IL-10. The elevated IL-23 mRNA levels in MS patients are noteworthy in view of the newly discovered IL-23-driven Th17 T-cell subset, which is crucial in animal models of MS. Since IFN-beta therapy resulted in decreased IL-23 mRNA levels, the Th17 axis could be another target of IFN-beta therapy.

Delivery of interferon-beta to the monkey nervous system following intranasal administration

We determined the nervous system targeting of interferon-beta1b (IFN-beta1b), a 20 kDa protein used to treat the relapsing-remitting form of multiple sclerosis, following intranasal administration in anesthetized, adult cynomolgus monkeys. Five animals received an intranasal bolus of [(125)I]-labeled IFN-beta1b, applied bilaterally to the upper nasal passages. Serial blood samples were collected for 45 min, after which the animals were euthanized by transcardial perfusion-fixation. High resolution phosphor imaging of tissue sections and gamma counting of microdissected tissue were used to obtain the distribution and concentration profiles of [(125)I]-IFN-beta1b in central and peripheral tissues. Intranasal administration resulted in rapid, widespread targeting of nervous tissue. The olfactory bulbs and trigeminal nerve exhibited [(125)I]-IFN-beta1b levels significantly greater than in peripheral organs and at least one order of magnitude higher than any other nervous tissue area sampled. The basal ganglia exhibited highest [(125)I]-IFN-beta1b levels among CNS regions other than the olfactory bulbs. Preferential IFN-beta1b distribution to the primate basal ganglia is a new finding of possible clinical importance. Our study suggests both IFN-beta and IFN-alpha, which share the same receptor, may be bound with relatively high affinity in these structures, possibly offering new insight into a neurovegetative syndrome induced by IFN-alpha therapy and suspected to involve altered dopamine neurotransmission in the basal ganglia. Most importantly, our results suggest intranasally applied macromolecules may bypass the blood-brain barrier and rapidly enter the primate CNS along olfactory- and trigeminal-associated extracellular pathways, as shown previously in the rat. This is the first study to finely detail the central distribution of a labeled protein after intranasal administration in non-human primates.

Interferon Beta-1b may reverse axonal dysfunction in multiple sclerosis

Progression of the disability of multiple sclerosis (MS) is thought to be related to axonal damage that is seen even in normal appearing white matter (NAWM) of patients' brains. Interferon beta (IFNβ) treatment for MS reduces the frequency of clinical exacerbations and the appearance of new inflammatory demyelinating lesions on magnetic resonance imaging (MRI). However, the effect of IFNβ treatment on axonal damage in MS is not known. The present study aimed to assess the effect of IFNβ on axonal function by comparing the data from localised single voxel proton MR spectroscopy (MRS) performed on eight MS patients given IFNβ-1b treatment and 11 untreated patients. Brain MRI and MRS were performed before the initiation of IFNβ-1b treatment and 24 months after treatment initiation. Levels of N-acetylaspartate (NAA), choline-containing compounds (Cho) and creatine (Cr) were calculated as the areas under their peaks shown on MRS and the ratios of NAA/Cr and Cho/Cr were calculated. In the patients treated with IFNβ-1b there was a significant increase in the ratio of NAA/Cr in NAWM (p=0.028) at 24 months after the initiation of treatment. In contrast, there was no significant change in the NAA/Cr ratio in the untreated patients. These results suggest that IFNβ-1b treatment might recover axonal function in NAWM of MS patients.

Effects of interferon-β on co-signaling molecules: upregulation of CD40, CD86 and PD-L2 on monocytes in relation to clinical response to interferon-β treatment in patients with multiple sclerosis

Interferon-beta (IFN-β) reduces disease activity in a subgroup of patients with relapsing remitting multiple sclerosis (MS). The mechanism of action as well as the pathophysiological basis of responsiveness to IFN-β is not well understood. Since T-cell activation plays an important part in the pathophysiology of MS, we here investigated the effect of IFN-β on the expression of co-signaling pathways (CD28—CD80/CD86, CD154—CD40, ICOS—ICOSL, PD-1—PD-L1/2) in MS patients and correlated the results with the clinical response to IFN-β in individual patients. Expression of co-signaling molecules was measured by flow cytometry in vitro on peripheral blood mononuclear cells after incubation with IFN-β, and in vivo in whole blood samples of 32 untreated and 24 IFN-β treated MS patients, including 13 patients longitudinal. IFN-β treatment induced upregulation of CD40, CD80, CD86, PD-L1 and PD-L2 on monocytes as well as PD-L1 on CD4+-T-cells in vitro and in vivo. IFN-β treated MS patients were grouped into responders and non-responders on the basis of Kurtzkés EDSS (expanded disability status scale) progression and relapse rate. Upregulation of CD40, CD86 and PD-L2 on monocytes was associated with treatment response to IFN-β ( P < 0.001, P = 0.028 and P = 0.028, respectively). Our results show that IFN-β upregulates co-stimulatory as well as co-inhibitory molecules in vitro and in vivo implicating that modulation of the balance between positive and negative co-stimulatory signals might be an important part of the mechanism of action of IFN-β in MS. Upregulation of the expression of CD40, CD86 and PD-L2 may be useful as a predictive marker for clinical response to IFN-β treatment at early timepoints during IFN-β therapy. Multiple Sclerosis 2008; 14: 166—176. http://msj.sagepub.com

Whole-brain N-acetylaspartate as a surrogate marker of neuronal damage in diffuse neurologic disorders

Proton MR spectroscopy (1H-MR spectroscopy) is a quantitative MR imaging technique often used to complement the sensitivity of conventional MR imaging with specific metabolic information. A key metabolite is the amino acid derivative N-acetylaspartate (NAA), which is almost exclusive to neurons and their processes and is, therefore, an accepted marker of their health and attenuation. Unfortunately, most 1H-MR spectroscopy studies only account for small 1- to 200-cm volumes of interest (VOI), representing less than 20% of the total brain volume. These VOIs have at least 5 additional restrictions: 1) To avoid contamination from subcutaneous and bone marrow lipids, they must be placed away from the skull, thereby missing most of the cortex. 2) They must be image-guided onto MR imaging-visible pathology, subjecting them to the implicit assumption that metabolic changes occur only there. 3) They encounter misregistration errors in serial studies. 4) The time needed to accumulate sufficient signal-intensity quality is often restrictive, and 5) they incur (unknown) T1- and T2-weighting. All these issues are avoided (at the cost of specific localization) by measuring the nonlocalized average NAA concentration over the entire brain. Indeed, whole-brain NAA quantification has been applied to several diffuse neurodegenerative diseases (where specific localization is less important than the total load of the pathology), and the results are presented in this review.

Prevalence of newly generated naive regulatory T cells (Treg) is critical for Treg suppressive function and determines Treg dysfunction in multiple sclerosis

The suppressive function of regulatory T cells (T(reg)) is impaired in multiple sclerosis (MS) patients. The mechanism underlying the T(reg) functional defect is unknown. T(reg) mature in the thymus and the majority of cells circulating in the periphery rapidly adopt a memory phenotype. Because our own previous findings suggest that the thymic output of T cells is impaired in MS, we hypothesized that an altered T(reg) generation may contribute to the suppressive deficiency. We therefore determined the role of T(reg) that enter the circulation as recent thymic emigrants (RTE) and, unlike their CD45RO(+) memory counterparts, express CD31 as typical surface marker. We show that the numbers of CD31(+)-coexpressing CD4(+)CD25(+)CD45RA(+)CD45RO(-)FOXP3(+) T(reg) (RTE-T(reg)) within peripheral blood decline with age and are significantly reduced in MS patients. The reduced de novo generation of RTE-T(reg) is compensated by higher proportions of memory T(reg), resulting in a stable cell count of the total T(reg) population. Depletion of CD31(+) cells from T(reg) diminishes the suppressive capacity of donor but not patient T(reg) and neutralizes the difference in inhibitory potencies between the two groups. Overall, there was a clear correlation between T(reg)-mediated suppression and the prevalence of RTE-T(reg), indicating that CD31-expressing naive T(reg) contribute to the functional properties of the entire T(reg) population. Furthermore, patient-derived T(reg), but not healthy T(reg), exhibit a contracted TCR Vbeta repertoire. These observations suggest that a shift in the homeostatic composition of T(reg) subsets related to a reduced thymic-dependent de novo generation of RTE-T(reg) with a compensatory expansion of memory T(reg) may contribute to the T(reg) defect associated with MS.

A Double-Blind, Randomized, Placebo-Controlled Comparison of Botulinum Toxin Type A Injection Sites and Doses in the Prevention of Episodic Migraine

BACKGROUND

Several randomized, controlled studies have reported benefits of botulinum toxin type A (BoNTA; Allergan Inc., Irvine, CA, USA) over placebo in the treatment of migraine. Some studies reported significant benefits at dosages as low as 16 U, while other studies reported safety, tolerability, and efficacy at dosages up to 260 U. However, the optimal treatment paradigm and patient population have yet to be defined.

OBJECTIVE

To compare different injection sites and doses of BoNTA in the prevention of episodic migraine.

DESIGN AND METHODS

This was a randomized, double-blind, placebo-controlled study of 232 patients with a history of four to eight moderate to severe migraines per month, with or without aura. Patients were randomized to placebo or one of four BoNTA groups that received injections into different muscle regions: frontal (10 U), temporal (6 U), glabellar (9 U), or all three areas (total dose 25 U). For 3 months following a single treatment, patients recorded migraine-related variables in a daily diary.

RESULTS

BoNTA and placebo produced comparable decreases from baseline in the frequency of migraines (P > or = 0.411). In general, no statistically significant differences were observed for any efficacy variable. The overall rates of adverse events (any type) or treatment-related adverse events were similar among the groups.

CONCLUSIONS

In this exploratory study of episodic migraine patients, low-dose injections of BoNTA into the frontal, temporal, and/or glabellar muscle regions were not more effective than placebo. BoNTA was safe and well tolerated. Future studies may examine higher BoNTA doses, flexible injection sites, multiple treatments, and disallow concomitant prophylactic medications.

Pharmacokinetics and pharmacodynamics of the interferon-betas, glatiramer acetate, and mitoxantrone in multiple sclerosis

Five disease-modifying agents are currently approved for long-term treatment of multiple sclerosis (MS), namely three interferon-beta preparations, glatiramer acetate, and mitoxantrone(1). Pharmacokinetics describes the fate of drugs in the human body by studying their absorption, distribution, metabolism and excretion. Pharmacodynamics is dedicated to the mechanisms of action of drugs. The understanding of the pharmacokinetics and pharmacodynamics of the approved disease-modifying agents against MS is of importance as it might contribute to the development of future derivatives with a potentially higher efficacy and a more favourable safety profile. This article reviews data thus far present both on the pharmacokinetics as well as on the putative mechanisms of action of the interferon-betas, glatiramer acetate, and mitoxantrone in the immunopathogenesis of MS.

FTY720 (fingolimod) in renal transplantation

FTY720 (Fingolimod) is a novel immunomodulator with a mode of action that is completely different from classical immunosuppressants. FTY is a structural and functional analogue of the natural serum lipid, sphingosine, and is the first in a new class of drugs called sphingosine 1-phosphate receptor (S1P-R) modulators. This review discusses the recent findings on the mechanism of action, preclinical models and outlines the results of the ongoing clinical development program. FTY is highly effective in prolonging allograft survival in preclinical models of transplantation and in experimental models of autoimmune diseases. In clinical trials, this novel compound was investigated in de novo renal transplantation and in multiple sclerosis. Pharmacokinetics are characterized by a prolonged absorption phase, a large volume of distribution, and a long elimination half-life. FTY induces a rapid and transient decrease in lymphocyte counts, which supports the modulatory effects of the drug on lymphocyte sequestration. The most common adverse event was asymptomatic transient bradycardia, a pharmacodynamic effect modulated by atrial S1 P-R. FTY failed to show an improvement in efficacy for the prevention of renal allograft rejection in two large phase III studies. FTY treatment regimens were associated with impaired renal function and the development of macula edema. Consequently, the further development in renal transplantation was stopped. Because initial clinical studies strongly suggest that FTY is highly effective in multiple sclerosis FTY is now being explored in phase III studies for the treatment of demyelinating diseases, Ongoing studies in multiple sclerosis are eagerly awaited because they may provide novel therapeutic options for patients with autoimmune diseases.

New Therapeutic Approaches for Multiple Sclerosis

Although several therapies exist for multiple sclerosis (MS), the most common inflammatory demyelinating disease of the central nervous system (CNS), there remains a large unmet clinical need for more effective immunomodulatory treatments in this category of diseases and for interventions that address their neurodegenerative component, which is currently untreated. Progress in our understanding of the immunology of MS over the past 30 years has recently synergized with novel computational methods and emerging high-throughput technologies that characterize variations in DNA, RNA, proteins, and metabolites to usher in a period of intense pathophysiologic investigation. These efforts are beginning to define subsets of patients with different forms of demyelinating disease. This partitioning of patients will prove valuable as we begin to tailor immunotherapy to the underlying pathophysiologic processes of individual patients using current therapies, emerging treatments, and rational combinations of all of these treatments. Preventing the entry of lymphocytes into the CNS and modifying the nature of the immune response are treatment approaches that work in the inflammatory component of MS but have little or no effect on neurodegeneration. Two challenges confront us: to develop cocktails of therapies that shift the immune homeostasis of patients with MS toward a healthy profile, and to identify and modulate the activity of targets within the neurodegenerative component of MS.

New insights into adaptive immunity in chronic neuroinflammation

Understanding the immune response in the central nervous system (CNS) is crucial for the development of new therapeutic concepts in chronic neuroinflammation, which differs considerably from other autoimmune diseases. Special immunologic properties of inflammatory processes in the CNS, which is often referred to as an immune privileged site, imply distinct features of CNS autoimmune disease in terms of disease initiation, perpetuation, and therapeutic accessibility. Furthermore, the CNS is a stress-sensitive organ with a low capacity for self-renewal and is highly prone to bystander damage caused by CNS inflammation. This leads to neuronal degeneration that contributes considerably to the phenotype of the disease. In this chapter, we discuss recent findings emphasizing the predominant role of the adaptive immune system in the pathogenesis of chronic neuroinflammation, that is, multiple sclerosis (MS) in patients and experimental autoimmune encephalomyelitis (EAE) in rodents. In addition, we report on efforts to translate these findings into clinical practice with the aim of developing selective treatment regimens.

Interferon-beta therapy reduces CD4+ and CD8+ T-cell reactivity in multiple sclerosis

Therapy with interferon-beta (IFN-beta) has well-established clinical effects in multiple sclerosis (MS), albeit the immunomodulatory mechanisms are not fully understood. We assessed the prevalence and functional capacity of CD4+ and CD8+ T cells in healthy donors, and in untreated and IFN-beta-treated MS patients, in response to myelin oligodendrocyte glycoprotein (MOG). The proportion of CD45RO+ memory T cells was higher in MS patients than in healthy donors, but returned to normal values upon therapy with IFN-beta. While CD45RO+ CD4+ T cells from all three groups responded to MOG in vitro, untreated patients showed augmented proliferative responses compared to healthy individuals and IFN-beta treatment reduced this elevated reactivity back to the values observed in healthy donors. Similarly, the response of CD45RO+ CD8+ T cells to MOG was strongest in untreated patients and decreased to normal values upon immunotherapy. Overall, the frequency of peripheral CD45RO+ memory T cells ex vivo correlated with the strength of the cellular in vitro response to MOG in untreated patients but not in healthy donors or IFN-beta-treated patients. Compared with healthy individuals, responding CD4+ and CD8+ cells were skewed towards a type 1 cytokine phenotype in untreated patients, but towards a type 2 phenotype under IFN-beta therapy. Our data suggest that the beneficial effect of IFN-beta in MS might be the result of the suppression or depletion of autoreactive, pro-inflammatory memory T cells in the periphery. Assessment of T-cell subsets and their reactivity to MOG may represent an important diagnostic tool for monitoring successful immunotherapy in MS.

Insulin resistance, inflammation, and cognition in Alzheimer's Disease: Lessons for multiple sclerosis

Insulin resistance (reduced ability of insulin to stimulate glucose utilization) is common in North American and Europe, where as many as one third of all older adults suffer from prodromal or clinical type 2 diabetes mellitus. It has long been known that insulin-resistant conditions adversely affect general health status. A growing body of findings suggests that insulin contributes to normal brain functioning and that peripheral insulin abnormalities increase the risk for memory loss and neurodegenerative disorders such as Alzheimer's disease. Potential mechanisms for these effects include insulin's role in cerebral glucose metabolism, peptide regulation, modulation of neurotransmitter levels, and modulation of many aspects of the inflammatory network. An intriguing question is whether insulin abnormalities also influence the pathophysiology of multiple sclerosis (MS), an autoimmune disorder characterized by elevated inflammatory biomarkers, central nervous system white matter lesions, axonal degeneration, and cognitive impairment. MS increases the risk for type 1 diabetes mellitus. Furthermore, the lack of association between MS and type 2 diabetes may suggest that insulin resistance affects patients with MS and the general population at the same alarming rate. Therefore, insulin resistance may exacerbate phenomena that are common to MS and insulin-resistant conditions, such as cognitive impairments and elevated inflammatory responses. Interestingly, the thiazolidinediones, which are used to treat patients with type 2 diabetes, have been proposed as potential therapeutic agents for both Alzheimer's disease and MS. The agents improve insulin sensitivity, reduce hyperinsulinemia, and exert anti-inflammatory actions. Ongoing studies will determine whether thiazolidinediones improve cognitive functioning for patients with type 2 diabetes or Alzheimer's disease. Future studies are needed to examine the effects of thiazolidinediones on patients with MS.