Production of brain-derived neurotrophic factor by mononuclear cells of patients with multiple sclerosis treated with glatiramer acetate, interferon-beta 1a, and high doses of immunoglobulins

The relevance of BDNF for neuroprotection and neuroplasticity in multiple sclerosis

Background

Neuroplasticity as a mechanism to overcome central nervous system injury resulting from different neurological diseases has gained increasing attention in recent years. However, deficiency of these repair mechanisms leads to the accumulation of neuronal damage and therefore long-term disability. To date, the mechanisms by which remyelination occurs and why the extent of remyelination differs interindividually between multiple sclerosis patients regardless of the disease course are unclear. A member of the neurotrophins family, the brain-derived neurotrophic factor (BDNF) has received particular attention in this context as it is thought to play a central role in remyelination and thus neuroplasticity, neuroprotection, and memory.

Objective

To analyse the current literature regarding BDNF in different areas of multiple sclerosis and to provide an overview of the current state of knowledge in this field.

Conclusion

To date, studies assessing the role of BDNF in patients with multiple sclerosis remain inconclusive. However, there is emerging evidence for a beneficial effect of BDNF in multiple sclerosis, as studies reporting positive effects on clinical as well as MRI characteristics outweighed studies assuming detrimental effects of BDNF. Furthermore, studies regarding the Val66Met polymorphism have not conclusively determined whether this is a protective or harmful factor in multiple sclerosis, but again most studies hypothesized a protective effect through modulation of BDNF secretion and anti-inflammatory effects with different effects in healthy controls and patients with multiple sclerosis, possibly due to the pro-inflammatory milieu in patients with multiple sclerosis. Further studies with larger cohorts and longitudinal follow-ups are needed to improve our understanding of the effects of BDNF in the central nervous system, especially in the context of multiple sclerosis.

The neuroprotective effect of human primary astrocytes in multiple sclerosis: In vitro model

Recent studies highlighted the role of astrocytes in neuroinflammatory diseases, particularly multiple sclerosis, interacting closely with other CNS components but also with the immune cells. However, due to the difficulty in obtaining human astrocytes, their role in these pathologies is still unclear. In this study we develop an astrocyte in vitro model to evaluate their role in multiple sclerosis after being treated with CSF isolated from both healthy and MS diagnosed patients. Gene expression and ELISA assays reveal that several pro-inflammatory markers IL-1β, TNF-α and IL-6, were significantly downregulated in astrocytes treated with MS-CSF. In contrast, neurotrophic survival, and growth factors, and GFAP, BDNF, GDNF and VEGF, were markedly elevated upon the same treatment. In summary, this study supports the notion of the astrocyte involvement in MS. The results reveal the neuroprotective role of astrocyte in MS pathogenicity by suppressing excessive inflammation and increasing the expression of tropic factors.

Exploring the mRNA and Plasma Protein Levels of BDNF, NT4, SIRT1, HSP27, and HSP70 in Multiple Sclerosis Patients and Healthy Controls

Multiple sclerosis (MS) is a chronic, autoimmune neurodegenerative disease affecting the central nervous system. It is a major cause of non-traumatic neurological disability among young adults in North America and Europe. This study focuses on neuroprotective genes (BDNF, NT4/5, SIRT1, HSP70, and HSP27). Gene expression and protein levels of these markers were compared between MS patients and healthy controls. Blood samples were collected from 42 patients with multiple sclerosis (MS) and 48 control subjects without MS. Quantitative real-time PCR was performed to measure the expression of specific genes. The samples were analyzed in duplicate, and the abundance of mRNA was quantified using the 2-ΔCt method. ELISA assay was used to measure the concentration of specific proteins in the plasma samples. The results show that a 3.5-fold decrease in the gene expression of BDNF corresponds to a 1.5-fold downregulation in the associated plasma protein concentration (p < 0.001). Similar trends were observed with NT-4 (five-fold decrease, slight elevation in protein), SIRT1 (two-fold decrease, two-fold protein decrease), HSP70 (four-fold increase, nearly two-fold protein increase), and HSP27 (four-fold increase, two-fold protein increase) (p < 0.001). This study reveals strong correlations between gene expression and protein concentration in MS patients, emphasizing the relevance of these neuroprotective markers in the disease.

The Role of BDNF in Multiple Sclerosis Neuroinflammation

Multiple sclerosis (MS) is a chronic, inflammatory, and degenerative disease of the central nervous system (CNS). Inflammation is observed in all stages of MS, both within and around the lesions, and can have beneficial and detrimental effects on MS pathogenesis. A possible mechanism for the neuroprotective effect in MS involves the release of brain-derived neurotrophic factor (BDNF) by immune cells in peripheral blood and inflammatory lesions, as well as by microglia and astrocytes within the CNS. BDNF is a neurotrophic factor that plays a key role in neuroplasticity and neuronal survival. This review aims to analyze the current understanding of the role that inflammation plays in MS, including the factors that contribute to both beneficial and detrimental effects. Additionally, it explores the potential role of BDNF in MS, as it may modulate neuroinflammation and provide neuroprotection. By obtaining a deeper understanding of the intricate relationship between inflammation and BDNF, new therapeutic strategies for MS may be developed.

Blood levels of brain-derived neurotrophic factor (BDNF) in people with multiple sclerosis (MS): A systematic review and meta-analysis

BACKGROUND

Multiple sclerosis is an autoimmune demyelinating disease marked by the involvement of multiple pathophysiological pathways, including BDNF. BDNF (brain-derived neurotrophic factor) is one of the main neurotrophic factors in the adult brain. The amount of BDNF in the blood can be utilized as a surrogate for the central expression of this marker. Given contradicting reports, we set out to answer the question, "How do blood levels of BDNF differ in people with multiple sclerosis (PwMS) compared to controls?"

METHODS

We performed a thorough search in MEDLINE, EMBASE, Web of Science, and the Cochrane Library databases, resulting in 13 eligible investigations. Eleven studies compared BDNF in serum of PwMS versus healthy controls (HC), and two studies provided BDNF levels in the plasma of PwMs. R version 4.0.4 was used for meta-analysis and visualizations. Mean difference (MD) was used for the measurement of effect size.

RESULTS

The final analysis included thirteen studies with 689 patients with MS and 583 controls. The preliminary results indicated that MS patients had statistically significant lower levels of BDNF than controls: SMD -5.1992 (95% CI [-8.4488; -1.9496], p-value < 0.0001. Additionally, subgroup analysis revealed a statistically significant difference in serum and plasma levels (p-value=0.01). Performing univariate meta-regression, disease duration and the proportion of males had, respectively, a significant negative and positive correlation with BDNF levels.

CONCLUSION

Circulating levels of BDNF are decreased in MS. Future studies should investigate the role of BDNF as a biomarker of disease severity and/or progression for a personalized approach to MS.

Melatonin and multiple sclerosis: antioxidant, anti-inflammatory and immunomodulator mechanism of action

BACKGROUND

Melatonin is an indole hormone secreted primarily by the pineal gland that showing anti-oxidant, anti-inflammatory and anti-apoptotic capacity. It can play an important role in the pathophysiological mechanisms of various diseases. In this regard, different studies have shown that there is a relationship between Melatonin and Multiple Sclerosis (MS). MS is a chronic immune-mediated disease of the Central Nervous System.

AIM

The objective of this review was to evaluate the mechanisms of action of melatonin on oxidative stress, inflammation and intestinal dysbiosis caused by MS, as well as its interaction with different hormones and factors that can influence the pathophysiology of the disease.

RESULTS

Melatonin causes a significant increase in the levels of catalase, superoxide dismutase, glutathione peroxidase, glutathione and can counteract and inhibit the effects of the NLRP3 inflammasome, which would also be beneficial during SARS-CoV-2 infection. In addition, melatonin increases antimicrobial peptides, especially Reg3β, which could be useful in controlling the microbiota.

CONCLUSION

Melatonin could exert a beneficial effect in people suffering from MS, running as a promising candidate for the treatment of this disease. However, more research in human is needed to help understand the possible interaction between melatonin and certain sex hormones, such as estrogens, to know the potential therapeutic efficacy in both men and women.

Serum level of brain-derived neurotrophic factor in patients with relapsing–remitting multiple sclerosis: a potential biomarker for disease activity

Background

Brain-derived neurotrophic factor (BDNF) is secreted by immune cells in response to neuroimmune and inflammatory cascades as an act to prevent axonal and neuronal damage after various pathological insults. The serum level of BDNF is altered in a diversity of neurological diseases. The aim of this work was to investigate the serum level of BDNF in patients with relapsing–remitting multiple sclerosis and the relation between BDNF and disease activity and severity.

Methods

A case–control study was conducted on 90 subjects: 60 patients with relapsing–remitting multiple sclerosis (30 in relapse and 30 in remission) on different lines of medical treatment and 30 healthy volunteers as a control. Clinical, functional, and radiological evaluation was done for the patients, and all the patients and controls were subjected to assessment of the serum level of BDNF by sandwich-ELISA technique.

Results

The BDNF level was significantly higher in MS patients in relapse than in patients in remission (P value = 0.006). In the remission group, there was no significant linear correlation between different MS patients’ characteristics and BDNF level, while in the relapse group, a positive linear correlation was found between the number of T2 infratentorial lesions and BDNF level (r = 0.402, P = 0.028). There was no statistically significant difference between the BDNF level in patients administered different drugs for MS in both remission and relapse groups (P value > 0.05).

Conclusion

BDNF was significantly higher in relapsing–remitting multiple sclerosis patients in the relapse phase. Attention should be paid to the link between serum BDNF level as a neuroprotective factor and multiple sclerosis; it can be a biomarker for MS activity in the near future.

The influence of glatiramer acetate on Th17-immune response in multiple sclerosis

Glatiramer acetate (GA) is approved for the treatment of multiple sclerosis (MS). However, the mechanism of action of GA in MS is still unclear. In particular, it is not known whether GA can modulate the pro-inflammatory Th17-type immune response in MS. We investigated the effects of original GA (Copaxone^®, Teva, Israel) and generic GA (Timexone^®, Biocad, Russia) on Th17- and Th1-type cytokine production in vitro in 25 patients with relapsing-remitting MS and 25 healthy subjects. Both original and generic GA at concentrations 50–200 μg/ml dose-dependently inhibited interleukin-17 and interferon-γ production by anti-CD3/anti-CD28-activated peripheral blood mononuclear cells from MS patients and healthy subjects. This effect of GA was reproduced using purified CD4⁺ T cells, suggesting that GA can directly modulate the functions of Th17 and Th1 cells. At high concentrations (100–200 μg/ml), GA also suppressed the production of Th17-differentiation cytokines (interleukin-1β and interleukin-6) by lipopolysaccharide (LPS)-activated dendritic cells (DCs). These GA/LPS-treated DCs induced lower interleukin-17 and interferon-γ production by autologous CD4⁺ T cells compared to LPS-treated DCs. These data suggest that GA can inhibit Th17-immune response and that this inhibitory effect is preferentially exercised by direct influence of GA on T cells. We also demonstrate a comparable ability of original and generic GA to modulate pro-inflammatory cytokine production.

12-months prospective Pentraxin-3 and metabolomic evaluation in multiple sclerosis patients treated with glatiramer acetate

BACKGROUND

Pentraxin-3 (PTX-3) is involved in acute immunological responses and it is a pro-inflammatory protein and a novel biomarker of inflammatory diseases. It is demonstrated that PTX-3 is higher in cerebrospinal fluid (CSF) of aggressive Multiple Sclerosis (MS). Metabolomics, the identification of small endogenous molecules, offers a molecular profile of MS. Glatiramer acetate (GA) is a widely used treatment for (MS) but its mechanism of action is not completely defined. The aim of our study is to analyze PTX-3 and metabolomic profile in MS patients compared to controls and to investigate the effect of GA on PXT-3 and metabolic molecules during treatment in responder and not responder MS patients.

METHODS

28 unrelated MS patients and 27 age-and sex-matched controls were recruited. In serum, PTX-3 levels were measured by ELISA and Metabolomic panel was evaluated trough Nuclear Magnetic Resonance (NMR). According to clinical practice patients started GA treatment; PTX-3 and metabolomic identification were performed before and during treatment. Responders to treatment were identified if no evidence of instrumental, clinical relapses and disability progression (NEDA) occurred during follow up.

RESULTS

Serum PTX-3 levels were higher in MS patients compared to matched controls (7,85 ± 2,19 vs 6,20 ± 1,63 ng/ml) (p = 0,03); metabolomic evaluation shows higher levels of lactate and lower levels of valine, tyrosine and tryptophan in MS patients compared to controls. During therapy, PTX-3 levels have been reduced statistically significant (p = 0,001) at six months and one year of treatment. After one year, of the twenty patients that completed the study, 55% were considered fully responders to treatment; in these patients the mean reduction of PTX-3 at one year was higher respect to not responders (-3,82 ± 1,24 ng/ml vs -2,32 ± 1,03 ng/ml p = 0,02) and we observed a higher reduction of lactate, tyrosine and hypoxanthine and an increase of hydroxyproline and ADP as well as of three oxidative phosphorylation markers, citrulline, ornithine and tryptophan approaching the metabolic profile of healthy subjects.

DISCUSSION AND CONCLUSIONS

We demonstrated a metabolomic imbalance with mitochondrial dysfunction detected by higher levels of lactate and lower levels of tryptophan, tyrosine and valine in MS patients compared to healthy controls. The reduction of PTX-3 levels and the restoring of mitochondrial function, reducing oxidative stress by GA, allows to identify responder patients. Further and larger studies are needed to understand the predictive role of PTX-3 and metabolomic pattern in the identification of responder patients to GA.

Interferon beta-1a induces expression of brain-derived neurotrophic factor in human T lymphocytes in vitro and not in vivo

Aim: To detect IFN β-1a-induced expression of brain-derived neurotrophic factor (BDNF) to undermine the hypothesis of IFN β-1a-associated neuroprotection in multiple sclerosis (MS). Methods: The influence of IFN β-1a on in vitro activated peripheral blood lymphocytes from healthy donors was tested. Proliferation analyses were made to detect T-cell growth. BDNF expression was measured by standard ELISA. To assess the influence of IFN β-1a on BDNF expression in vivo, BDNF serum levels of MS patients treated with IFN β-1a were compared with those of untreated patients. Results: IFN β-1a inhibited T-cell proliferation dose dependently. It induced BDNF expression at middle concentrations. MS patients treated with IFN β-1a exhibited significantly lower BDNF serum levels than untreated patients. Conclusion: IFN β-1a may promote neuroprotection by inducing BDNF expression, but its importance in vivo remains open.

Glatiramer acetate attenuates renal ischemia reperfusion injury in rat model

Chronic renal failure can ultimately lead to kidney transplantation. Renal transplantation is associated with ischemia-reperfusion injury (I/R).² The subsequent processes of kidney I/R can lead to irreversible damages to the kidney tissue. Glatiramer acetate is an immunomodulatory drug for the treatment of multiple sclerosis (MS) and the anti-inflammatory effects of this drug have already been proven in some inflammatory models. The purpose of this study was to evaluate the protective effects of Glatiramer on reducing the damages arising from kidney ischemia-reperfusion. In this study, 35 Wistar rats were used which divided into 5 groups: sham, control (I/R), I/R + Glatiramer 0.5 mg/kg, I/R + Glatiramer 1 mg/kg, I/R + Glatiramer 2 mg/kg. Renal arteries were clamped bilaterally for 45 min, then the clamps were removed and the reperfusion process continued to 24 h. In the following, serum and kidneys were separated for analysis. In the control group, serum levels of LDH, inflammatory factor TNF-α and renal functional markers such as BUN and Creatinine were remarkably increased, but in the treatment groups, especially in Glatiramer 2 mg/kg received group, a significant decrease in these factors was observed. Tissue concentration of MDA was reduced following Glatiramer treatment. Besides, Glatiramer attenuated the increased kidney level of NF-κB protein using immunohistochemical assay. NFkB migration to the nucleolus increases inflammatory cytokines production. The anti-inflammatory factor, IL-10, in serum was significantly increased in the treatment group of Glatiramer 2 mg/kg. Furthermore, Glatiramer decreased renal tissue injury score according to the histopathological study. These results demonstrate that Glatiramer may play protective effects in kidney ischemia-reperfusion injury by reducing inflammatory and oxidative damages.

[Brain-derived neurotrophic factor in multiple sclerosis]

The review presents data on brain-derived neurotrophic factor (BDNF), its structure and functions, the effect on the pathogenesis of experimental autoimmune encephalomyelitis and multiple sclerosis (MS). The correlation of BDNF level with clinical manifestations of MS and the changes of its level during disease-modifying therapy is considered.

The Evolving Mechanisms of Action of Glatiramer Acetate

Glatiramer acetate (GA) is a synthetic amino acid copolymer that is approved for treatment of relapsing remitting multiple sclerosis (RRMS) and clinically isolated syndrome (CIS). GA reduces multiple sclerosis (MS) disease activity and has shown comparable efficacy with high-dose interferon-β. The mechanism of action (MOA) of GA has long been an enigma. Originally, it was recognized that GA treatment promoted expansion of GA-reactive T-helper 2 and regulatory T cells, and induced the release of neurotrophic factors. However, GA treatment influences both innate and adaptive immune compartments, and it is now recognized that antigen-presenting cells (APCs) are the initial cellular targets for GA. The anti-inflammatory (M2) APCs induced following treatment with GA are responsible for the induction of anti-inflammatory T cells that contribute to its therapeutic benefit. Here, we review studies that have shaped our current understanding of the MOA of GA.

Hydroxyfasudil alleviates demyelination through the inhibition of MOG antibody and microglia activation in cuprizone mouse model

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system characterized by oligodendrocyte loss and progressive neurodegeneration. The cuprizone (CPZ)-induced demyelination is widely used to investigate the demyelination/remyelination. Here, we explored the therapeutic effects of Hydroxyfasudil (HF), an active metabolite of Fasudil, in CPZ model. HF improved behavioral abnormality and reduced myelin damage in the corpus callosum. Splenic atrophy and myelin oligodendrocyte glycoprotein (MOG) antibody were observed in CPZ model, which were partially restored and obviously inhibited by HF, therefore reducing pathogenic binding of MOG antibody to oligodendrocytes. HF inhibited the percentages of CD4⁺IL-17⁺ T cells from splenocytes and infiltration of CD4⁺ T cells and CD68⁺ macrophages in the brain. HF also declined microglia-mediated neuroinflammation, and promoted the production of astrocyte-derived brain derived neurotrophic factor (BDNF) and regeneration of NG2⁺ oligodendrocyte precursor cells. These results provide potent evidence for the therapeutic effects of HF in CPZ-induced demyelination.

Clinical and Environmental Correlates of Serum BDNF: A Descriptive Study with Plausible Implications for AD Research

BACKGROUND

Brain derived neurotrophic factor (BDNF) may play a central role in the pathogenesis of Alzheimer's disease (AD) through neurotrophic effects on basal cholinergic neurons. Reduced serum levels of BDND are observed among AD patients and may predict AD risk. Nevertheless, knowledge about factors associated with its levels in blood is lacking.

OBJECTIVE

To identify clinical and demographic correlates of serum BDNF levels.

METHODS

BDNF was measured from serum collected between 1992-1996 and 1998-2001 in participants from the Original and Offspring cohorts of the Framingham Study, respectively. A cross-sectional analysis was done to evaluate the relationship between clinical measures and BDNF levels using standard linear regression and stepwise models. Analyses were conducted in the total sample and separately in each cohort, and were adjusted for age and sex.

RESULTS

BDNF was measured in 3,689 participants (mean age 65 years, 56% women; 82% Offspring). Cigarette smoking and high total cholesterol were associated with elevated BDNF levels, and history of atrial fibrillation was associated with decreased levels. Elevated BDNF levels were related to greater physical activity and lower Tumor Necrosis Factor-α levels in Offspring. Stepwise models also revealed associations with statin use, alcohol consumption and Apolipoprotein Eε4 genotype.

CONCLUSION

Serum BDNF correlates with various metabolic, inflammatory and life-style measures which in turn have been linked with risk of AD. Future studies of serum BDNF should adjust for these correlates and are needed to further explore the underlying interplay between BDNF and other factors in the pathophysiology of cognitive impairment and AD.

Fingolimod inhibits brain atrophy and promotes brain-derived neurotrophic factor in an animal model of multiple sclerosis

Longitudinal brain atrophy quantification is a critical efficacy measurement in multiple sclerosis (MS) clinical trials and the determination of No Evidence of Disease Activity (NEDA). Utilising fingolimod as a clinically validated therapy we evaluated the use of repeated brain tissue volume measures during chronic experimental autoimmune encephalomyelitis (EAE) as a new preclinical efficacy measure. Brain volume changes were quantified using magnetic resonance imaging (MRI) at 7 Tesla and correlated to treatment-induced brain derived neurotrophic factor (BDNF) measured in blood, cerebrospinal fluid, spinal cord and brain. Serial brain MRI measurements revealed slow progressive brain volume loss in vehicle treated EAE mice despite a stable clinical score. Fingolimod (1 mg/kg) significantly ameliorated brain tissue atrophy in the cerebellum and striatum when administered from established EAE disease onwards. Fingolimod-dependent tissue preservation was associated with induction of BDNF specifically within the brain and co-localized with neuronal soma. In contrast, therapeutic teriflunomide (3 mg/kg) treatment failed to inhibit CNS autoimmune mediated brain degeneration. Finally, weekly anti-IL-17A antibody (15 mg/kg) treatment was highly efficacious and preserved whole brain, cerebellum and striatum volume. Fingolimod-mediated BDNF increases within the CNS may contribute to limiting progressive tissue loss during chronic neuroinflammation.

The Effect of Glatiramer Acetate on Spinal Cord Volume in Relapsing-Remitting Multiple Sclerosis

BACKGROUND

Spinal cord atrophy occurs early in the multiple sclerosis (MS) disease course, is closely related to physical disability, and is a putative neuroprotective therapeutic outcome measure.

OBJECTIVE

This pilot study explored glatiramer acetate (GA)'s effect on spinal cord volume in patients with relapsing-remitting MS (RRMS).

METHODS

Fifteen patients receiving daily subcutaneous GA were prospectively followed. At baseline, age was 43.6 ± 7.4 years, Expanded Disability Status Scale (EDSS) score was 1.4 ± 1.5, timed 25-foot walk (T25FW) was 4.7 ± 1.1 seconds, and time on GA was 2.1 ± 3.1 years. Healthy controls (n = 10) with similar age and sex to the patients were also enrolled. The spinal cord was imaged at baseline and one year later with 3T magnetic resonance imaging. An active surface method measured the C1-C7 spinal cord volume from which we calculated the normalized area.

RESULTS

The spinal cord area showed no significant change in the MS group over one year (P = .19). Furthermore, the change in the spinal cord area did not differ significantly between the MS and control groups over one year (P = .26). In the MS group, the EDSS score (P = .44) and T25FW (P = .92) did not change significantly on-study.

CONCLUSION

In this pilot study of RRMS, GA therapy was not associated with any ongoing spinal cord atrophy or any difference in the one-year rate of spinal cord area change versus healthy controls. These results paralleled the lack of clinical worsening and may reflect a treatment effect of GA. Further studies are needed to confirm these preliminary findings.

Predictive cytokine biomarkers of clinical response to glatiramer acetate therapy in multiple sclerosis

A prospective study of 62 patients with relapsing-remitting multiple sclerosis (RRMS) treated with Glatiramer acetate (GA) was conducted to evaluate the value of baseline and treatment-modulated cytokines in predicting the clinical response to the drug after 2years of therapy. There were 32 responders and 30 non-responders. GA upregulated Th2/regulatory cytokines and inhibited Th1 cytokines in sera or PBMC supernatants 3 and 6months into treatment. We found two prognostic models with clinical utility. A model based on IL-18 at baseline, the change in TNFa from baseline to 3months, the change in IL-4 from baseline to 6months, and the change in the log of the ratio of TNFa/IL-4 from baseline to 6months had an area under the curve (AUC) of 0.80. A high IL-18 level at baseline and a reduction of TNF-alpha over time are associated with a response to GA. Although the study identified predictive biomarkers of clinical response to GA, the results will need to be validated in other data sets.

Functional electrical stimulation as a component of activity-based restorative therapy may preserve function in persons with multiple sclerosis

OBJECTIVE

To examine the effect of functional electrical stimulation (FES) cycling on disability progression in persons with multiple sclerosis (MS).

DESIGN

Retrospective cohort, 40 participants with mean follow-up of 15 months. Setting International Center for Spinal Cord Injury at Kennedy Krieger Institute in Baltimore, a rehabilitation referral center.

PARTICIPANTS

Forty consecutive persons with MS undergoing rehabilitation from 2007 to 2011, with at least two evaluations based on the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). Interventions FES cycling as part of activity-based restorative therapy interventions.

OUTCOME MEASURES

Change in Expanded Disability Status Scale (EDSS) and ISNCSCI motor, light touch, and pin prick scores from baseline to latest evaluation.

RESULTS

In 71% of patients, activity-based rehabilitation included FES cycling. There was no disability progression on the EDSS. Lower extremity motor scores improved or stabilized in 75% of patients with primary progressive MS (PPMS), 71.4% with secondary progressive MS (SPMS), and 54.5% with relapsing remitting MS (RRMS). Among patients with improved or stabilized lower extremity motor function, PPMS recorded a mean 9% improvement, SPMS 3% and RRMS 6%. In PPMS, use of FES showed trend towards improvement in motor scores (P = 0.070).

CONCLUSIONS

FES as part of activity-based rehabilitation may help preserve or improve neurological function in patients with MS.

The pharmacokinetics of glatiramer acetate for multiple sclerosis treatment

INTRODUCTION

Multiple sclerosis (MS) is a T-cell-mediated disease affecting the central nervous system (CNS), characterized by demyelination and axonal degeneration. INF-β1b was the first drug approved for MS patients in 1993. In 1996, glatiramer acetate (GA), a synthetic copolymer, was approved in the USA for the treatment of relapsing-remitting MS (RRMS) and clinically isolated syndrome (CIS). Although the immunological action of GA has been fully investigated, the exact mechanisms of action of GA are still not completely elucidated. Several in vitro studies on mice and human antigen-presenting cells (APCs) have shown that GA is able to bind to the major histocompatibility complex (MHC), on the surface of APCs, recognizing myelin basic protein (MBP).

AREAS COVERED

This review explores the pharmacological characteristics of GA, its mechanism of action and its pharmacokinetics properties. The article also provides information on the efficacy, tolerability and an overview of the most important clinical data on GA.

EXPERT OPINION

Despite the development of novel compounds, it is not surprising that GA is, to date, one of the most prescribed drugs for RRMS patients and CIS patients. The proven efficacy and the mild adverse events, makes GA a good therapeutic option in the early stage of the disease. This is particularly useful for patients who suffer flu-like symptoms from other RRMS therapies as an alternative.

Interferon beta and glatiramer acetate therapy

Interferon beta and glatiramer acetate have been mainstays of treatment in relapsingremitting multiple sclerosis for two decades. Remarkable advances in our understanding of immune function and dysfunction as well as increasingly sophisticated clinical trial design have stemmed from efforts to better understand these drugs. In this chapter, we review the history of their development and elaborate on known and theorized mechanisms of action. We describe the pivotal clinical trials that have led to their widespread use. We evaluate the clinical use of the drugs including tolerability, side effects, and efficacy measures. Finally, we look to the future of interferon beta and glatiramer acetate in the context of an ever growing armamentarium of treatments for relapsing remitting multiple sclerosis.

The role of neurotrophins in multiple sclerosis-pathological and clinical implications

Multiple sclerosis (MS) is a chronic inflammatory demyelinating and neurodegenerative disease of the central nervous system (CNS) with unknown etiology. It was recently suggested that autoimmunity, which had long been considered to be destructive in MS, might also play a protective role in the CNS of MS patients. Neurotrophins are polypeptides belonging to the neurotrophic factor family. While neurotrophins mediate cell survival and proliferation in the nervous system, they are also expressed within peripheral blood mononuclear cells fraction (PBMCs) of immunological system. In MS additional neurotrophic support from PBMCs might compensate relative neurotrophins deficiency in the damaged CNS tissue that needs to be repaired. Failure to produce the adequate neurotrophins concentrations might result in decreased protection of the CNS, consequently leading to increased atrophy, which is the main determinant of MS patients' end-point disability. There are several lines of evidence, both from clinical research and animal models, suggesting that neurotrophins play a pivotal role in neuroprotective and neuroregenerative processes that are often defective in the course of MS. It seems that neuroprotective strategies might be used as potentially valuable add-on therapies, alongside traditional immunomodulatory treatment in multiple sclerosis.

What do effective treatments for multiple sclerosis tell us about the molecular mechanisms involved in pathogenesis?

Multiple sclerosis is a potentially debilitating disease of the central nervous system. A concerted program of research by many centers around the world has consistently demonstrated the importance of the immune system in its pathogenesis. This knowledge has led to the formal testing of a number of therapeutic agents in both animal models and humans. These clinical trials have shed yet further light on the pathogenesis of MS through their sometimes unexpected effects and by their differential effects in terms of impact on relapses, progression of the disease, paraclinical parameters (MRI) and the adverse events that are experienced. Here we review the currently approved medications for the commonest form of multiple sclerosis (relapsing-remitting) and the emerging therapies for which preliminary results from phase II/III clinical trials are available. A detailed analysis of the molecular mechanisms responsible for the efficacy of these medications in multiple sclerosis indicates that blockade or modulation of both T- and B-cell activation and migration pathways in the periphery or CNS can lead to amelioration of the disease. It is hoped that further therapeutic trials will better delineate the pathogenesis of MS, ultimately leading to even better treatments with fewer adverse effects.

Immune response during interferon beta-1b treatment in patients with multiple sclerosis who experienced relapses and those who were relapse-free in the START study

We measured immune markers in subjects with multiple sclerosis (MS) treated with IFNβ-1b for 12 months. IL-17 levels were significantly higher at Month 6 (p=0.036) in relapsing subjects while BDNF levels were significantly higher at Month 3 (p=0.028) in relapse-free subjects. Change from baseline in IL-4 levels inversely correlated with disability score whereas change from baseline in IL-10/IFN-gamma ratio inversely correlated with occurrence of relapses. CXCR3+CD8+ T-cells tended to be higher but declined with treatment in relapse-free compared with relapsing subjects. Findings show the potential of cytokine and neurotrophic factors as biomarkers of clinical response to IFNβ-1b.

Stimulation of the neurotrophin receptor TrkB on astrocytes drives nitric oxide production and neurodegeneration

Neurotrophin growth factors support neuronal survival and function. In this study, we show that the expression of the neurotrophin receptor TrkB is induced on astrocytes in white matter lesions in multiple sclerosis (MS) patients and mice with experimental autoimmune encephalomyelitis (EAE). Surprisingly, mice lacking TrkB specifically in astrocytes were protected from EAE-induced neurodegeneration. In an in vitro assay, astrocytes stimulated with the TrkB agonist brain-derived neurotrophic factor (BDNF) released nitric oxide (NO), and conditioned medium from activated astrocytes had detrimental effects on the morphology and survival of neurons. This neurodegenerative process was amplified by NO produced by neurons. NO synthesis in the central nervous system during EAE depended on astrocyte TrkB. Together, these findings suggest that TrkB expression on astrocytes may represent a new target for neuroprotective therapies in MS.

Levels of BDNF impact oligodendrocyte lineage cells following a cuprizone lesion

Previous work in culture has shown that basal forebrain (BF) oligodendrocyte (OLG) lineage cells respond to BDNF by increasing DNA synthesis and differentiation. Further, in the BF in vivo, reduced levels of BDNF as seen in BDNF(+/-) mice result in reduced numbers of NG2+ cells and deficits in myelin proteins throughout development and in the adult, suggesting that BDNF impacts the proliferating population of OLGs as well as differentiation in vivo. In this study, to investigate the roles BDNF may play in the repair of a demyelinating lesion, the cuprizone model was used and the corpus callosum was examined. BDNF protein levels were reduced after cuprizone treatment, suggesting that the demyelinating lesion itself elicits a decrease in BDNF. To analyze the effects of a further reduction of BDNF on OLG lineage cells following cuprizone, BDNF(+/-) mice were evaluated. These mice exhibited a blunted increase in the NG2 response at 4 and 5 weeks of cuprizone treatment. In addition, BDNF(+/-) mice exhibited decreased levels of myelin proteins during the demyelination and remyelination processes with no change in the total number of OLGs. These effects appear to be relatively specific to OLG lineage cells as comparable changes in CD11b+ microglia, GFAP+ astrocytes, and SMI32+ injured axons were not observed. These data indicate that BDNF may play a role following a demyelinating lesion by regulating the numbers of progenitors and the abilities of demyelinating and differentiating cells to express myelin proteins.

Low and dysregulated production of follistatin in immune cells of relapsing-remitting multiple sclerosis patients

One of the mechanisms known to play a key role in neuronal and oligodendroglial fate specification of neural stem cells (NSCs) is restriction of bone morphogenic proteins (BMP) signaling by BMP antagonists. Here, we demonstrate that follistatin mRNA and protein secreted levels in peripheral blood mononuclear cells (PBMCs) of relapsing-remitting multiple sclerosis (RR-MS) patients are significantly reduced compared to healthy controls (HC). We also observed a different profile of regulation mechanisms. Follistatin was similarly expressed and secreted by T lymphocytes and monocytes among the PBMCs of HC, and follistatin upregulation of HC was subjected to stimulation with both LPS and TNF-α. Among PBMCs of RR-MS patients, however, follistatin was found to be downregulated in their monocytes and unresponsive to stimulation with either LPS or TNF-α. Our results may shed some light on the mechanisms involved in remyelination failure in MS, which may be related to the inability of RR-MS patients' immune cells to provide a sufficient pro-neurogenic and oligodendrogenic niche, by expressing and secreting follistatin, in addition to the previously described noggin reduced expression. Our results indicate that the low expression of follistatin in immune cells of patients with RR-MS is a result of the altered immunoregulation of monocytes in these patients.

The balance of pro-inflammatory and trophic factors in multiple sclerosis patients: effects of acute relapse and immunomodulatory treatment

Background: In multiple sclerosis inflammation is primarily injurious to the central nervous system, but its therapeutic suppression might inhibit repair-promoting factors.

Objectives: We aimed at better describing the complexity of biological effects during an acute relapse and analysed the effects of intervention with high-dose i.v. glucocorticoids and immunomodulatory treatment with interferon-beta (IFNβ).

Methods: We studied the intracellular expression levels of the pro-inflammatory mediators tumour necrosis factor alpha (TNFα) and inducible nitric oxide synthase (iNOS) together with the neurotrophins ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) in freshly isolated peripheral blood mononuclear cells of multiple sclerosis patients during an acute relapse, after intervention with i.v. methylprednisolone and at baseline, using a highly quantitative flow-cytometric approach.

Results: We demonstrated the expression of CNTF in human leucocytes. We showed that CNTF levels differed in acutely relapsing multiple sclerosis patients compared with controls and increased after corticosteroid treatment. CNTF can counteract the toxicity of TNFα towards oligodendrocytes and we found TNFα increased during acute relapses. Following corticosteroids, neither TNFα nor iNOS expression was reduced. Levels of BDNF were not affected by glucocorticoids, but increased during IFNβ therapy. However, IFNβ also increased the expression of iNOS and major histocompatibility complex class I (MHC-I), underlining its immunomodulatory potential.

Conclusions: Multiple sclerosis patients might benefit from reparative, and not solely from anti-inflammatory, effects of glucocorticoids. Interactive effects of glucocorticoid- and IFNβ-treatment need to be considered to improve neuroprotection and remyelination resulting from immunomodulatory treatment.

Glatiramer acetate could be a hypothetical therapeutic agent for neuromyelitis optica

Neuromyelitis optica (NMO) is characterized by concurrence of optic neuritis and transverse myelitis, which is typically associated with a spinal cord lesion extending three or more vertebral segments. NMO is an inflammatory, demyelinating central nervous system disorder, and although it has a relapsing course in more than 90% of patients, it differs from multiple sclerosis in that it is more severe, usually spares the brain, and is associated with a longitudinally extensive lesion on spinal cord magnetic resonance imaging (MRI). Furthermore, NMO is associated with a highly specific serum marker called anti-aquaporin-4 antibody, which is believed to have a central pathogenetic role in NMO. Treatment with B-cell specific monoclonal antibody (rituximab) and plasma exchanges appears to reduce the severity and frequency of attacks in NMO, and therefore, B-cell autoimmunity as well as a humoral mechanism may be involved in the pathogenesis of NMO. Glatiramer acetate (GA; also known as Copaxone, COP-1) is a synthetic copolymer of a pool of peptides composed of random sequences of four amino acids: glutamine, lysine, alanine, and tyrosine. GA-specific T-helper 1- (Th1) and 2-type (Th2) cells produce brain-derived neurotrophic factor (BDNF), which may affect neuronal survival and myelin repair. GA treatment also leads to sustained augmentation of BDNF, neurotrophin (NT)-3, and NT-4 expression in various brain regions as demonstrated by histological analysis of immunostained brain sections and BDNF elevation after GA treatment on both protein and mRNA levels. GA-Th2 activation may also have a neuroprotective role in the course of NMO. Furthermore, B cells from GA-treated mice suppress experimental autoimmune encephalomyelitis. The pathogenesis of NMO is largely unknown. However, there is some evidence that B-cell autoimmunity, activation of eosinophils, and B-cell activating factor play important roles, based on neurotrophic factors, neuroprotection, anti-inflammation, and B-cell modulation, GA is thus a hypothetic potential treatment agent for NMO.

Therapeutic approaches to multiple sclerosis: an update on failed, interrupted, or inconclusive trials of neuroprotective and alternative treatment strategies

Currently approved multiple sclerosis (MS) therapeutics have a mainly anti-inflammatory mode of action. However, a number of promising clinical trials have been initiated that either focus on neuroprotection or follow completely different treatment strategies. So far, all of these clinical trials have failed to show efficacy or had to be halted prematurely because of unexpected adverse events. Some others show results that are of unknown significance with regard to a reliable assessment of true efficacy versus safety. For example, trials addressing the highly promising sodium channel blockers are under close observation because of potential adverse effects after drug withdrawal. Previously failed therapeutic approaches in MS have indicated that there are discrepancies between the theoretical expectations and practical outcomes of different compounds. Learning from these failures helps to optimize future study designs and to reduce risks to patients. This review summarizes trials on MS treatments since 2001 that failed or were interrupted, attempts to analyze the underlying reasons for failure, and discusses the implications for our current view of MS pathogenesis, clinical practice, and the design of future studies. In order to maintain clarity, this review focuses on neuroprotective and various other treatment strategies. Clinical trials addressing anti-inflammatory research strategies are presented elsewhere.

Reduced production of noggin by immune cells of patients with relapsing-remitting multiple sclerosis

Multiple sclerosis (MS) plaques are characterized by neurodegeneration, astrogliolis, the presence of immature oligodendrocytes and infiltrating immune cells. Recent studies revealed a putative role for noggin in both neurogenesis and oligodenrocytes development. In order to study the potential of peripheral immune cells to contribute to neurogenesis in MS, we studied the mRNA expression, protein secretion and regulation profile of noggin in peripheral blood mononuclear cells (PBMCs) of untreated patients with relapsing-remitting MS (RR-MS), interferon-β (IFN-β) treated RR-MS patients compared to matched healthy controls (HC). Basal levels of noggin mRNA expression, determined by quantitative real-time PCR were lower in untreated patients than in HC. No differences were found between untreated patients and IFN-β treated patients. Similarly, the secreted levels of noggin, detected in 24h PBMCs supernatants by ELISA, were decreased in untreated RR-MS patients than in HC. Again no significant differences were found between untreated patients and IFN-β treated patients. Stimulation with anti-CD3/CD28 mAbs increased noggin mRNA expression in untreated patients but not in HC. However, noggin mRNA levels in untreated patients PBMCs stimulated with anti-CD3/CD28 did not reach noggin levels in unstimulated PBMCs of HC. Purification of monocytes (CD14+) and T cells (CD3+ cells) by magnet-activated cell separation has demonstrated that noggin mRNA is predominantly expressed in CD3(+) cells in both HC and in RR-MS patients. This pattern also appeared in protein level of noggin, tested by Western blot. The incubation of the PBMCs with TNF-α increased the expression of noggin only in HC group. In conclusion, T cells possess the potential to participate in the induction of neurogeneration by the production of noggin. This potential seems to be defective in immune cells of RR-MS patients as there is reduced mRNA expression and protein secretion levels of noggin, insufficient stimulatory effect of CD3/CD28 stimulation and unresponsiveness to TNF-α in these patients PBMCs.

Altered production of brain-derived neurotrophic factor by peripheral blood immune cells in multiple sclerosis

Background: Within multiple sclerosis lesions, brain-derived neurotrophic factor is detected in neurons and immunocytes.

Objective: To clarify brain-derived neurotrophic factor production by peripheral blood immunocytes and its relationship with clinical parameters in multiple sclerosis.

Methods: Serum brain-derived neurotrophic factor levels were measured by conventional enzyme-linked immunosorbent assay while brain-derived neurotrophic factor production by immunocytes was determined by an in situ enzyme-linked immunosorbent assay in 74 multiple sclerosis patients, 32 healthy controls, and 86 patients with other neurological diseases. The tyrosine kinase receptor TrkB expression level in peripheral blood mononuclear cells was measured by real-time polymerase chain reaction.

Results: Multiple sclerosis patients showed significantly higher serum brain-derived neurotrophic factor levels than healthy controls and patients with other neurological diseases. Multiple sclerosis patients with high brain-derived neurotrophic factor levels were younger, and showed fewer relapse numbers than those with low brain-derived neurotrophic factor levels. Brain-derived neurotrophic factor production by T cells increased with age in healthy controls, but not in multiple sclerosis patients. Interferon beta induced a significant increase in serum brain-derived neurotrophic factor levels. Brain-derived neurotrophic factor production from T cells and TrkB expression levels in peripheral blood mononuclear cells were significantly enhanced in interferon beta-treated multiple sclerosis patients compared with untreated ones. Conclusions: A high brain-derived neurotrophic factor level is related to early mild disease in young multiple sclerosis patients. Interferon beta potentiates brain-derived neurotrophic factor production and brain-derived neurotrophic factor receptor expression in peripheral blood mononuclear cells, which may act beneficially.

Correlations between peripheral blood mononuclear cell production of BDNF, TNF-alpha, IL-6, IL-10 and cognitive performances in multiple sclerosis patients

The aim of this study was to investigate the role of Brain Derived Neurotrophic Factor (BDNF) and inflammatory factors in the development of cognitive dysfunctions in Multiple Sclerosis (MS). We correlated peripheral blood mononuclear cell (PBMC) production of BDNF, Tumor Necrosis Factor-alpha (TNF-alpha), Interleukin (IL)-6 and IL-10 with performances on specific neuropsychological tasks in a selected series of MS patients. We studied a sample of 30 patients with relapsing-remitting (RR)MS, segregated by gender and matched for age, education, disease duration, type of immunomodulating therapy, degree of disability and overall cognitive status. We found that low BDNF levels were correlated with increased time of execution on a divided attention and visual scanning task whereas high levels of IL-6 were correlated with low Mini Mental State Examination scores. We did not observe any significant correlations between IL-10, TNF-alpha levels and cognitive performances in our patients. In conclusion our study shows a correlation between low BDNF and high IL-6 production by PBMCs and poorer performances in cognitive tasks in RRMS patients suggesting a possible role of these factors in cognitive impairment in MS.

Effect of Met66 allele of the BDNF rs6265 SNP on regional gray matter volumes in patients with multiple sclerosis: A voxel-based morphometry study

The rs6265 single nucleotide polymorphism (SNP) is a genetic variation in the brain-derived neurotrophic factor (BDNF) gene wherein the presence of the A-allele at rs6265 causes replacement of a valine (Val) at position 66 by methionine (Met). We reported recently that the Met66 allele was associated with lower brain damage as evidenced by measurement of gray matter (GM) volume in multiple sclerosis (MS) patients. The objective of this study was to determine the voxel-wise regional GM differences between the Val66Val and Met66 allele groups in MS patients by using voxel-based morphometry (VBM)-optimized analysis corrected for lesion misclassification in Statistical Parametric Mapping (SPM5). High-resolution 3D-T1-weighted SPGR images from a total of 188 MS patients were acquired on a 1.5T MRI. The Val66Val group included 129 MS patients and the Met66 allele group (comprised of Val66Met or Met66Met genotypes) included 59 MS patients. The SPM analysis of covariance tool was used to assess group differences after controlling for variation in head size, MS disease course and gender. VBM analysis did not yield significant family wise error (FWE) corrected results. This was also confirmed with the non-parametric analysis using threshold-free cluster enhancement (TFCE) method. However, the results from VBM as well as the TFCE analyses (p<0.001, uncorrected) showed higher GM volume in the cingulate of MS patients with Met66 allele than those with Val66Val. Future studies are warranted to investigate longitudinally possible protective role of the Met66 allele of the BDNF rs6265 SNP in relation to specific GM regions.

Strategies to promote differentiation of newborn neurons into mature functional cells in Alzheimer brain

Adult neurogenesis occurs in the subgranular zone (SGZ) and subventricular zone (SVZ). New SGZ neurons migrate into the granule cell layer of the dentate gyrus (DG). New SVZ neurons seem to enter the association neocortex and entorhinal cortex besides the olfactory bulb. Alzheimer disease (AD) is characterized by neuron loss in the hippocampus (DG and CA1 field), entorhinal cortex, and association neocortex, which underlies the learning and memory deficits. We hypothesized that, if the AD brain can support neurogenesis, strategies to stimulate the neurogenesis process could have therapeutic value in AD. We reviewed the literature on: (a) the functional significance of adult-born neurons; (b) the occurrence of endogenous neurogenesis in AD; and (c) strategies to stimulate the adult neurogenesis process. We found that: (a) new neurons in the adult DG contribute to memory function; (b) new neurons are generated in the SGZ and SVZ of AD brains, but they fail to differentiate into mature neurons in the target regions; and (c) numerous strategies (Lithium, Glatiramer Acetate, nerve growth factor, environmental enrichment) can enhance adult neurogenesis and promote maturation of newly generated neurons. Such strategies might help to compensate for the loss of neurons and improve the memory function in AD.

Increased plasma levels of brain derived neurotrophic factor (BDNF) after multiple sclerosis relapse

Brain derived neurotrophic factor (BDNF) has been related to neuroprotection in a series of central nervous system diseases, although its role in multiple sclerosis (MS) was only partially investigated. In this work, we aimed to evaluate the plasma levels of BDNF from 29 MS patients and 24 control subjects. MS patients had decreased levels of BDNF in comparison with healthy controls. BDNF levels increased significantly after MS relapse. Our results provide some evidence for the involvement of BDNF in the pathogenesis of MS and suggest a role for this neurotrophin during the recovery of acute demyelinating inflammatory lesion.

Gender-related differences in MS: a study of conventional and nonconventional MRI measures

Background

Studies showed gender-associated differences in multiple sclerosis (MS) disease evolution and in the evolution of conventional magnetic resonance imaging (MRI) findings.

Objective

The aim of this study was to investigate gender differences according to a number of conventional and nonconventional MRI measures in patients with MS.

Methods

We examined 763 consecutive patients with MS [499 (19.2% men) relapsing-remitting (RR), 230 (24.8% men) secondary-progressive, and 34 (44.1% men) primary-progressive], 32 (21.9% men) patients with clinically isolated syndrome (CIS), and 101 (30.7% men) normal controls (NC). Patients were assessed using conventional and nonconventional MRI measures. Gender-related MRI differences were investigated using general linear model analysis, corrected for MS disease type.

Results

In the total MS group, male patients showed lower normalized peripheral gray matter (GM) ( P < 0.001) and normalized GM ( P = 0.011) volumes than female patients. Female patients presented lower normalized white matter (WM) volumes ( P = 0.011). These gender effects were not observed in NC. Male patients also showed more advanced central atrophy ( P = 0.022). In RRMS male patients, there was also a higher lateral ventricle volume ( P = 0.001). The GM-WM normalized ratio was lower for male patients with MS compared with male NC (0.97 vs. 1.09, P < 0.001) but not in patients with CIS compared with NC.

Conclusions

There were no significant gender-related differences regarding nonconventional MRI measures. GM and central atrophy are more advanced in male patients, whereas WM atrophy is more advanced in female patients. These gender-related MRI differences may be explained by the effect of sex hormones on brain damage and repair mechanisms.

A longitudinal observation of brain-derived neurotrophic factor mRNA levels in patients with relapsing-remitting multiple sclerosis

This report is part of a 2-year study assessing the functional effect of Brain-Derived Neurotrophic Factor (BDNF) and its Val66Met polymorphism on a selected population of Relapsing-Remitting Multiple Sclerosis (RRMS) patients from Southern Italy. For this purpose, we measured the peripheral BDNF expression in RRMS patients compared to healthy controls. The influence of concomitant IFNbeta therapy was also evaluated. Thirty-six inactive RRMS patients and 37 healthy controls were genotyped for BDNF Val66Met, and total RNA was extracted at time-points 0-24 months. The BDNF level was quantified by ABI Prism 7900 HT Sequence Detection System, and its relative expression was calculated by the comparative method of 2(-DeltaDeltaCt). At baseline and after 24 months, the BDNF levels of RRMS patients resulted significantly higher than controls (p=0.001), independently of the concomitant IFNbeta treatment; no correlations were found with the investigated clinical and MRI features of MS. Otherwise, carriers of the Met-allele showed significantly higher levels of BDNF in RRMS patients than healthy controls (p=0.005). These data was replicated after a 24-month interval. The present study confirms the increased levels of peripheral BDNF levels in RRMS, even during the inactive phase of the disease. Although with caution due to the small sample size, it also underscores the potential role of the Val66Met polymorphism on the peripheral BDNF expression in RRMS. Functional studies are needed to better clarify this issue.

Protective autoimmunity in the nervous system

The immune system can play both detrimental and beneficial roles in the nervous system. Multiple arms of the immune system, including T cells, B cells, NK cells, mast cells, macrophages, dendritic cells, microglia, antibodies, complement and cytokines participate in limiting damage to the nervous system during toxic, ischemic, hemorrhagic, infective, degenerative, metabolic and immune-mediated insults and also assist in the process of repair after injury has occurred. Immune cells have been shown to produce neurotrophic growth factors and interact with neurons and glial cells to preserve them from injury and stimulate growth and repair. The immune system also appears to participate in proliferation of neural progenitor stem cells and their migration to sites of injury. Neural stem cells can also modify the immune response in the central and peripheral nervous system to enhance neuroprotective effects. Evidence for protective and reparative functions of the immune system has been found in diverse neurologic diseases including traumatic injury, ischemic and hemorrhagic stroke, multiple sclerosis, infection, and neurodegenerative diseases (Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis). Existing therapies including glatiramer acetate, interferon-beta and immunoglobulin have been shown to augment the protective and regenerative aspects of the immune system in humans, and other experimental interventions such as vaccination, minocycline, antibodies and neural stem cells, have shown promise in animal models of disease. The beneficent aspects of the immune response in the nervous system are beginning to be appreciated and their potential as pharmacologic targets in neurologic disease is being explored.

Interferon-beta induces brain-derived neurotrophic factor in peripheral blood mononuclear cells of multiple sclerosis patients

Interferon-beta (IFN-beta) achieves its beneficial effect on multiple sclerosis (MS) via anti-inflammatory properties. In this study, we assessed the expression of the brain-derived neurotrophic factor (BDNF) in peripheral blood mononuclear cells (PBMC) from relapsing-remitting multiple sclerosis (RRMS) patients treated or not with IFN-beta. Intracellular BDNF was measured by Western blot and ELISA and compared with serum BDNF. We found higher levels of BDNF in PBMC of IFN-beta-treated versus non-treated patients, whereas serum levels of BDNF were similar. We hypothesize that the increased intracellular BDNF secondary to IFN-beta is not released in the periphery. This release is probably not tissue specific but in MS patients, BDNF could be specifically delivered by PBMC at the site of re-activation, i.e. within the central nervous system.

From fish to man: understanding endogenous remyelination in central nervous system demyelinating diseases

In the central nervous system (CNS) of man, evolutionary pressure has preserved some capability for remyelination while axonal regeneration is very limited. In contrast, two efficient programmes of regeneration exist in the adult fish CNS, neurite regrowth and remyelination. The rapidity of CNS remyelination is critical since it not only restores fast conduction of nerve impulses but also maintains axon integrity. If myelin repair fails, axons degenerate, leading to increased disability. In the human CNS demyelinating disease multiple sclerosis (MS), remyelination often takes place in the midst of inflammation. Here, we discuss recent studies that address the innate repair capabilities of the axon-glia unit from fish to man. We propose that expansion of this research field will help find ways to maintain or enhance spontaneous remyelination in man.

Preservation of gray matter volume in multiple sclerosis patients with the Met allele of the rs6265 (Val66Met) SNP of brain-derived neurotrophic factor

To investigate the association of the rs6265 (Val66Met) single nucleotide polymorphism (SNP) of brain-derived neurotrophic factor (BDNF) with brain morphometry and functional status as measured by quantitative magnetic resonance imaging (MRI) and neurocognitive testing in multiple sclerosis (MS) patients. BDNF is released by neurons and by immune cells in MS brain. The rs6265 SNP variation of BDNF causes substitution of valine (Val) for methionine (Met) and interferes with activity-dependent BDNF secretion. A total of 209 treated MS patients (161 females; 48 males) underwent clinical brain MRI and were genotyped for the BDNF rs6265 Val66Met SNP. A subset of 108 patients had neurocognitive testing for processing speed, memory and executive function. The MRI measurements included T2 and T1-lesion volume (LV); normalized brain volume measures of whole brain (WB) volume, white and gray matter volume (NWMV and NGMV) and the diffusion-weighted imaging measure of WB mean parenchyma diffusivity (MPD). The Met66 allele status was positively associated with NGMV (P = 0.015, standardized beta = 0.15) and negatively associated with T2-LV (P = 0.041, standardized beta = -0.14). There were no significant associations between Met66 allele status and T1-LV, NWMV or MPD. On the Paced Serial Addition Test (PASAT), a trend (P = 0.057) favoring the Met66 allele group was observed. There were no significant associations between Met66 allele status and other neurocognitive measures. The BDNF Met66 allele is associated with lower damage as evidenced by measurement of NGMV and T2-LV in MS patients.