Evolution of brain-derived neurotrophic factor levels after autologous hematopietic stem cell transplantation in multiple sclerosis

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.

Brain-derived neurotropic factor and GABAergic transmission in neurodegeneration and neuroregeneration

Neurotoxicity induced by stress, radiation, chemicals, or metabolic diseases, is commonly associated with excitotoxicity, oxidative stress, and neuroinflammation. The pathological process of neurotoxicity induces neuronal death, interrupts synaptic plasticity in the brain, and is similar to that of diverse neurodegenerative diseases. Animal models of neurotoxicity have revealed that clinical symptoms and brain lesions can recover over time via neuroregenerative processes. Specifically, brain-derived neurotropic factor (BDNF) and gamma-aminobutyric acid (GABA)-ergic transmission are related to both neurodegeneration and neuroregeneration. This review summarizes the accumulating evidences that suggest a pathogenic role of BDNF and GABAergic transmission, their underlying mechanisms, and the relationship between BDNF and GABA in neurodegeneration and neuroregeneration. This review will provide a comprehensive overview of the underlying mechanisms of neuroregeneration that may help in developing potential strategies for pharmacotherapeutic approaches to treat neurotoxicity and neurodegenerative disease.

Brain-derived neurotrophic factor in neuroimmunology: lessons learned from multiple sclerosis patients and experimental autoimmune encephalomyelitis models

The concept of neuroprotective autoimmunity implies that immune cells, especially autoantigen-specific T cells, infiltrate the central nervous system (CNS) after injury and contribute to neuroregeneration and repair by secreting soluble factors. Amongst others, neurotrophic factors and neurotrophins such as brain-derived neurotropic factor (BDNF) are considered to play an important role in this process. New data raise the possibility that this concept could also be extended to neuroinflammatory diseases such as multiple sclerosis (MS) where autoantigen-specific T cells infiltrate the CNS, causing axonal/neuronal damage on the one hand, but also providing neuroprotective support on the other hand. In this review, we summarize the current knowledge on BDNF levels analyzed in MS patients in different compartments and its correlation with clinical parameters. Furthermore, new approaches in experimental animal models are discussed that attempt to decipher the functional relevance of BDNF in autoimmune demyelination.

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.

The role of neurotrophic factors in the pathology and treatment of multiple sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disease of primary autoimmune origin with essential component of subsequent axonal degeneration. It has been found that inflammatory cells crucial for MS pathogenesis are able to release neurotrophic factors (NFs). Thus the concept of neuroprotective effect of inflammation has arisen. Over recent years, increasing number of studies has revealed that NFs play an important role in MS and its animal model - experimental autoimmune encephalomyelitis (EAE). In the current review the evidence for the role of NFs in MS pathogenesis the same as their remarkable potential in MS therapy is presented.

Cerebrospinal fluid biomarkers in multiple sclerosis

In patients with multiple sclerosis (MS) intensive efforts are directed at identifying biomarkers in bodily fluids related to underlying disease mechanisms, disease activity and progression, and therapeutic response. Besides MR imaging parameters cerebrospinal fluid (CSF) biomarkers provide important and specific information since changes in the CSF composition may reflect disease mechanisms inherent to MS. The different cellular and protein-analytical methods of the CSF and the recommended standard of the diagnostic CSF profile in MS are described. A brief update on possible CSF biomarkers that might reflect key pathological processes of MS such as inflammation, demyelination, neuroaxonal loss, gliosis and regeneration is provided.

Autologous haematopoietic stem-cell transplantation in multiple sclerosis

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

Autologous and allogeneic hematopoietic stem cell transplantation for Multiple Sclerosis: perspective on mechanisms of action

Multiple Sclerosis (MS) is a frequent demyelinating immune-mediated disease of the central nervous system (CNS) that affects principally young adults and leads to severe physical and cognitive impairment. The current standard treatment makes use of the immune modulators beta-interferon, glatiramer acetate and natalizumab, or immunosuppressants such as mitoxantrone. However, these agents are only partially effective and in a number of patients fail to achieve satisfactory disease control. Autologous hematopoietic stem cell transplantation (HSCT) is being explored in the treatment of severe MS as a means of delivering high-dose immunosuppression followed by 'rescue' of the immuno-hematopoietic system with autologous HSC. The potential therapeutic benefit is based on the concept of so-called 'resetting' the immune system. The use of allogeneic HSCT as a possible therapeutic approach for severe MS is inspired by case reports of MS patients that underwent allogeneic HSCT for a concomitant hematological malignancy, and subsequently is supported by data from rodent models of MS. Allogeneic HSCT may offer specific therapeutic effects, such as the replacement of the autoreactive immune compartment by healthy allogeneic cells and the development of a graft-versus-autoimmunity (GVA) effect. Here, we review the currently available experimental and clinical evidence to support the role of autologous and allogeneic HSCT in MS.

Effect of glatiramer acetate (Copaxone®) on the immunophenotypic and cytokine profile and BDNF production in multiple sclerosis: A longitudinal study

We assessed the effect of glatiramer acetate (GA) on the immunophenotypic and cytokine profile and the BDNF production by peripheral blood mononuclear cells, and their association with the clinical response in 19 naïve-treated MS patients prospectively followed-up after GA therapy. Two patients withdrew the therapy. After a median follow-up of 21 months, twelve were considered responders and five as non-responders. Non-responder patients had significant longer disease duration and a higher EDSS score at baseline. In the responder group, a significant decrease in the percentage of INF-gamma producing total lymphocytes, CD4+ and CD8+ T cells, and reduced percentage of IL-2 producing CD4+ and CD8+ T cells were observed at 12, 18 and 24 months. These changes were associated with a significant increase in the percentage of CD3+, CD4+ and CD4(+) CD45RA(+) T cells, and BDNF production from month 6 that remained significant throughout the study. We did not observe significant changes in the nonresponder group for any of the parameters studied. Our data suggest that GA treatment induces a downmodulation of proinflammatory cytokines associated with the regulation of the peripheral T cell compartment and with increased production of BDNF that might be related to the clinical response.

No association of the Val66Met polymorphism of brain-derived neurotrophic factor (BDNF) to multiple sclerosis

Brain-derived neurotrophic factor (BDNF), a neurotrophin produced by neurons and immune cells, promotes neuronal survival and repair during development and after CNS injury. The BDNF-Val66Met polymorphism is functional and induces abnormal intracellular trafficking and decreased BDNF release. Therefore, we investigated the impact of the BDNF-Val66Met polymorphism on the susceptibility and clinical course in a case-control study of 224 multiple sclerosis (MS) Spanish patients and 177 healthy controls. We found no evidence for association to susceptibility or severity of the disease in our population. Moreover, we did not observe, in a subgroup of 12 MS patients, that the methionine substitution at position 66 in the prodomain had negative impact in the capacity to produce BDNF by peripheral blood mononuclear cells (PBMC).

Trophic factors in cerebrospinal fluid and spinal cord of patients with tropical spastic paraparesis, HIV, and Creutzfeldt-Jakob disease

HTLV-1-associated myelopathy/tropical spastic paraparesis (TSP/HAM) is a chronic CNS disease characterized by axomyelinic degeneration of the long axons of corticospinal tracts. Levels of NGF, NT-3, NT-4/5, BDNF, GDNF, CNTF, and FGF-2 were measured in the cerebrospinal fluid (CSF) of 21 TSP/HAM patients and 20 controls. NGF, BDNF, and FGF-2 levels were also determined in 19 patients with HIV motor cognitive motor syndrome, and in 21 subjects diagnosed with Creutzfeldt Jakob disease (CJD). No significant differences were detected in the concentrations of NGF, BDNF, NT-3, NT-4/5, GDNF, and CNTF in the CSF between TSP/HAM patients and controls. FGF-2 was significantly lower in the CSF of the three groups of patients compared with controls; the HIV group exhibited the lowest values. HIV patients differed from TSP/HAM in their significantly higher levels of NGF and lower levels of BDNF and FGF-2, whereas CJD patients differed only in their higher levels of NGF. Immunohistochemical studies were done of trophic factors (NGF and FGF-2) and neurotrophin receptors (trkA and p75) in spinal cord and motor cortical areas from anatomopathological cases of TSP/HAM. Results indicated that NGF is expressed in motoneurons and oligodendrocytes of the posterior column of the spinal cord. FGF-2 was detected in motoneurons and spinal cord vessels. p75 receptor was detected in cortical neurons. The absence of a significant change in the trophic factor levels in TSP/HAM may be attributed to a selective axonal lesion in a slow process.