BackgroundMultiple Sclerosis (MS) is an acquired inflammatory demyelinating disorder of the central nervous system (CNS) and is the leading cause of nontraumatic disability among young adults. Activated microglial cells are important effectors of demyelination and neurodegeneration, by secreting cytokines and others neurotoxic agents. Previous studies have demonstrated that microglia expresses ATP-sensitive potassium (KATP) channels and its pharmacological activation can provide neuroprotective and anti-inflammatory effects. In this study, we have examined the effect of oral administration of KATP channel opener diazoxide on induced experimental autoimmune encephalomyelitis (EAE), a mouse model of MS.MethodsAnti-inflammatory effects of diazoxide were studied on lipopolysaccharide (LPS) and interferon gamma (IFNγ)-activated microglial cells. EAE was induced in C57BL/6J mice by immunization with myelin oligodendrocyte glycoprotein peptide (MOG35-55). Mice were orally treated daily with diazoxide or vehicle for 15 days from the day of EAE symptom onset. Treatment starting at the same time as immunization was also assayed. Clinical signs of EAE were monitored and histological studies were performed to analyze tissue damage, demyelination, glial reactivity, axonal loss, neuronal preservation and lymphocyte infiltration.ResultsDiazoxide inhibited in vitro nitric oxide (NO), tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) production and inducible nitric oxide synthase (iNOS) expression by activated microglia without affecting cyclooxygenase-2 (COX-2) expression and phagocytosis. Oral treatment of mice with diazoxide ameliorated EAE clinical signs but did not prevent disease. Histological analysis demonstrated that diazoxide elicited a significant reduction in myelin and axonal loss accompanied by a decrease in glial activation and neuronal damage. Diazoxide did not affect the number of infiltrating lymphocytes positive for CD3 and CD20 in the spinal cord.ConclusionTaken together, these results demonstrate novel actions of diazoxide as an anti-inflammatory agent, which might contribute to its beneficial effects on EAE through neuroprotection. Treatment with this widely used and well-tolerated drug may be a useful therapeutic intervention in ameliorating MS disease.

Pharmacological modulation of ATP-sensitive potassium channels has become a promising new therapeutic approach for the treatment of neurodegenerative diseases due to their role in mitochondrial and cellular protection. For instance, diazoxide, a well-known ATP-sensitive potassium channel activator with high affinity for mitochondrial component of the channel has been proved to be effective in animal models for different diseases such as Alzheimer’s disease, stroke or multiple sclerosis. Here, we analyzed the ability of diazoxide for protecting neurons front different neurotoxic insults in vitro and ex vivo. Results showed that diazoxide effectively protects NSC-34 motoneurons from glutamatergic, oxidative and inflammatory damage. Moreover, diazoxide decreased neuronal death in organotypic hippocampal slice cultures after exicitotoxicity and preserved myelin sheath in organotypic cerebellar cultures exposed to pro-inflammatory demyelinating damage. In addition, we demonstrated that one of the mechanisms of actions implied in the neuroprotective role of diazoxide is mediated by the activation of Nrf2 expression and nuclear translocation. Nrf2 expression was increased in NSC-34 neurons in vitro as well as in the spinal cord of experimental autoimmune encephalomyelitis animals orally administered with diazoxide. Thus, diazoxide is a neuroprotective agent against oxidative stress-induced damage and cellular dysfunction that can be beneficial for diseases such as multiple sclerosis.

Many neurodegenerative diseases are associated, at least in part, to an inflammatory process in which microglia plays a major role. The effect of the triglyceride form of the omega-3 polyunsaturated fatty acid docosahexaenoic acid (TG-DHA) was assayed in vitro and in vivo to assess the protective and anti-inflammatory activity of this compound. In the in vitro study, BV-2 microglia cells were previously treated with TG-DHA and then activated with Lipopolysaccharide (LPS) and Interferon-gamma (IFN-γ). TG-DHA treatment protected BV-2 microglia cells from oxidative stress toxicity attenuating NO production and suppressing the induction of inflammatory cytokines. When compared with DHA in the ethyl-ester form, a significant difference in the ability to inhibit NO production in favor of TG-DHA was observed. TG-DHA inhibited significantly splenocyte proliferation but isolated CD4+ lymphocyte proliferation was unaffected. In a mice model of autoimmune encephalomyelitis (EAE), 250 mg/kg/day oral TG-DHA treatment was associated with a significant amelioration of the course and severity of the disease as compared to untreated animals. TG-DHA-treated EAE mice showed a better weight profile, which is a symptom related to a better course of encephalomyelitis. TG-DHA may be a promising therapeutic agent in neuroinflammatory processes and merit to be more extensively studied in human neurodegenerative disorders.

Summary:In a retrospective study, we compared 15 patients who received cyclosporine (CsA), methotrexate (MTX) and prednisone (PDN) and 15 patients who received CsA-MTX for GVHD prophylaxis after allogeneic BMT (HLA-identical sibling (n ‫؍‬ 22), related one HLA mismatch (n ‫؍‬ 1), unrelated matched donors (n ‫؍‬ 6), unrelated one HLA mismatch (n ‫؍‬ 1)). The primary objectives of this study were to compare the incidence of GVHD and post-transplantation complications. Secondary objectives were to compare relapse rate, transplantrelated mortality and overall survival. The incidence of acute GVHD grade III-IV was similar between the two groups (P ‫؍‬ 0.66), as was the incidence of chronic GVHD (P ‫؍‬ 0.67). Incidence of arterial hypertension was significantly higher in patients who received prophylactic PDN, (P ‫؍‬ 0.03) and more insulin treatment was required in this group (P ‫؍‬ 0.003). We observed no differences in the incidence of infections or upper digestive tract bleeding. Musculoskeletal complications appeared earlier in the group which received PDN. With a median follow-up of 4.4 years, patients in the CsA-MTX group had better overall survival, 46.7% vs 13.3% (P ‫؍‬ 0.026). Relapse was a more frequent cause of death in the CsA-MTX group, whereas procedure-related mortality was more frequent in the CsA-MTX-PDN group (P ‫؍‬ 0.013). These results suggest that prophylactic prednisone when combined with cyclosporine and methotrexate adds no benefit in acute or chronic GVHD prevention and may increase the morbidity of allogeneic transplantation. Corticosteroids may be reserved for GVHD treatment. Acute graft-versus-host disease (GVHD) continues to be a major complication after allogeneic bone marrow transplantation and develops in 30-60% of recipients of histocompatible sibling-matched allografts. Mortality due directly or indirectly to GVHD may reach 50%. 1,2When allogeneic transplants were performed without GVHD prophylaxis, very high rates of GVHD were observed 3 and Sullivan et al 4 reported a case of hyperacute GVHD.Prophylaxis with methotrexate is associated with a 40-50% incidence of GVHD, 5,6 and several studies demonstrated that cyclosporine A (CsA) and methotrexate (MTX) alone were equally effective in preventing GVHD. 7-9The combination of CsA and MTX decreased the incidence of GVHD in several randomised controlled trials. This combination is associated with a significantly lower rate (20-30%) of II-IV acute GVHD than when using MTX or CsA as single-agent.5,10-13 However, a similar diseasefree survival was observed when comparing CsA plus MTX vs CsA alone because there was a more frequent incidence of relapse when MTX was part of GVHD prevention. 11Other investigators added corticosteroids to either MTX, cyclophosphamide or CsA. They found an advantage in CsA plus prednisone compared to the other combinations. This combination allowed for more rapid hematopoietic recovery compared with MTX-containing regimens, albeit at the price of a higher incidence of GVHD than seen with MTX plus CsA. [14][15][16] N...

Activation of mitochondrial ATP-sensitive potassium (K ATP ) channels is postulated as an effective mechanism to confer cardio and neuroprotection, especially in situations associated to oxidative stress. Pharmacological activation of these channels inhibits glia-mediated neuroinflammation. In this way, diazoxide, an old-known mitochondrial K ATP channel opener, has been proposed as an effective and safe treatment for different neurodegenerative diseases, demonstrating efficacy in different animal models, including the experimental autoimmune encephalomyelitis (EAE), an animal model for Multiple Sclerosis. Although neuroprotection and modulation of glial reactivity could alone explain the positive effects of diazoxide administration in EAE mice, little is known of its effects on the immune system and the autoimmune reaction that triggers the EAE pathology. The aim of the present work was to study the effects of diazoxide in autoimmune key processes related with EAE, such as antigen presentation and lymphocyte activation and proliferation. Results show that, although diazoxide treatment inhibited in vitro and ex-vivo lymphocyte proliferation from whole splenocytes it had no effect in isolated CD4 + T cells. In any case, treatment had no impact in lymphocyte activation. Diazoxide can also slightly decrease CD83, CD80, CD86 and major histocompatibility complex class II expression in cultured dendritic cells, demonstrating a possible role in modulating antigen presentation. Taken together, our results indicate that diazoxide treatment attenuates autoimmune encephalomyelitis pathology without immunosuppressive effect.