Viral pathogens in multiple sclerosis: an intriguing (hi)story.
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Herpesvirus 6, Human↗
Biomedical subjects
Olaf Stüve
Publications and source records attributed to Olaf Stüve.
Statins as potential therapeutic agents in multiple sclerosis.
3-Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (ie, statins) are oral cholesterol-lowering drugs. Statins are well tolerated and have an excellent safety record. These agents competitively inhibit HMG CoA reductase, which is the enzyme that catalyzes the conversion of HMG CoA to L-mevalonate. Although L-mevalonate is a key intermediate in cholesterol synthesis, several of its metabolites are involved in post-translational modification of specific proteins involved in cell proliferation and differentiation. Thus, independent of their cholesterol-reducing properties, statins have important pleiotropic biologic effects. Recent reports indicate that statins have anti-inflammatory and neuroprotective properties. Whether statins will be of clinical benefit for patients with multiple sclerosis and other neurodegenerative diseases of the central nervous system will only be known after they are evaluated in prospective randomized clinical trials.
Humans↗
Are statins a treatment option for multiple sclerosis?
BACKGROUND: Treatment options for multiple sclerosis (MS) are limited. The immunomodulatory drugs interferon beta and glatiramer acetate are only partly effective in reducing the relapse rate, slowing disease progression, and diminishing the number and volume of lesions on MRI. Mitoxantrone is an immunosuppressant approved for the treatment of active forms of relapsing-remitting or secondary progressive MS, but is dose-limited owing to its potential cardiotoxicity. Thus, identifying new effective therapeutic options with few side-effects is highly desirable. RECENT DEVELOPMENTS: Evidence has emerged that statins, which are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, have immunomodulatory effects. Recent reports showed that statins prevent and reverse chronic and relapsing experimental autoimmune encephalomyelitis, an animal model of MS. Furthermore, in vitro experiments with human immune cells have shown an immunomodulatory profile of statins comparable to that of interferon beta. An open label clinical trial of simvastatin for MS revealed a significant decrease in the number and volume of new MRI lesions and a favourable safety profile. WHERE NEXT?: The obvious advantage of statins over existing MS therapies is their oral route of dosing. Statins might be beneficial for MS patients as monotherapy or as an add-on to established disease modifying drugs. As the evidence of the benefit of statins in MS is currently insufficient, large controlled clinical trials are needed. The first of these trials is about to start.
Adjuvants, Immunologic↗
Mitoxantrone as a potential therapy for primary progressive multiple sclerosis.
Mitoxantrone (Novantrone) was the first drug approved in western Europe and North America for treatment of secondary progressive multiple sclerosis (SPMS) and progressive relapsing MS (PRMS). Pharmacological properties of mitoxantrone, its role in SPMS, the study rational and design of an ongoing multi-centre, double blind, randomized, placebo-controlled phase 2 trial will be outlined in this article.
Humans↗
Statins as potential therapeutic agents in neuroinflammatory disorders.
PURPOSE OF REVIEW: Multiple sclerosis is a central nervous system inflammatory demyelinating disease that is thought to have an autoimmune pathogenesis. Recent results indicate that 'statins', 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, which are the most commonly used oral cholesterol-lowering drugs, have immunomodulatory properties. In this article we will review those findings that indicate that statins may be beneficial in the treatment of multiple sclerosis, neurodegenerative disease, and ischemic stroke. RECENT FINDINGS: It was reported that statin treatment could either inhibit or reverse chronic and relapsing experimental autoimmune encephalomyelitis, a model of multiple sclerosis. Several immunomodulatory properties of statins may account for their beneficial clinical effect: Statins decreased the migration of leukocytes into the central nervous system, inhibited MHC class II and costimulatory signals required for activation of proinflammatory T cells, induced a T(H)2 phenotype in T cells, and decreased the expression of inflammatory mediators in the central nervous system, including nitric oxide and tumor necrosis factor alpha. It was also demonstrated that statin use significantly reduced beta-amyloid secretion in the cerebrospinal fluid of experimental animals. Clinically, there is emerging evidence that statins have beneficial effects in patients with multiple sclerosis, Alzheimer's disease, and ischemic stroke. SUMMARY: In-vitro studies have indicated that statins may have anti-inflammatory properties. Results from in-vivo animal models suggest that statins may be beneficial in treatment of different central nervous system conditions. Larger scale, randomized, double-blind trials are needed to validate the role of statins as a treatment of inflammatory central nervous system diseases.
Alzheimer Disease↗
Statins and their potential targets in multiple sclerosis therapy.
Multiple sclerosis (MS) is a CNS-demyelinating disease characterised by relapsing and chronic neurological impairment. While traditionally CNS autoantigen-specific CD4(+) T cells have been considered the culprits in the initial phase of the disease, recent observations have altered this concept. It is now recognised that other T lymphocyte subclasses can initiate CNS demyelination. In addition, other cell types and molecules may play an important role in MS pathogenesis. There is overwhelming evidence that MS is a dynamic process, in which recurrent episodes of blood-brain barrier disruption and CNS inflammation play a crucial role in early disease stages, leading eventually to the largely irreversible changes of demyelination, gliosis and axonal degeneration. These observations may have important therapeutic implications. Within the last ten years, several medications have been approved for MS treatment. These agents, all of which are given parenterally, are only partially effective and are often associated with adverse effects and potential toxicities. The number and different types of medications used for MS are likely to increase in the near future, as several novel therapies are currently tested in clinical trials. 3-hydroxy-3-methyglutaryl coenzyme A reductase inhibitors, 'statins', are cholesterol-lowering drugs that are given orally, are safe and have biological effects independent of their cholesterol-reducing properties. Recent reports have shown that statins have anti-inflammatory and neuroprotective properties that may be beneficial in the treatment of MS. This article will outline experimental evidence that suggests potential clinical benefits of statins for MS patients.
Adult↗
The role of the MHC class II transactivator in class II expression and antigen presentation by astrocytes and in susceptibility to central nervous system autoimmune disease.
The role of the MHC class II transactivator (CIITA) in Ag presentation by astrocytes and susceptibility to experimental autoimmune encephalomyelitis (EAE) was examined using CIITA-deficient mice and newly created transgenic mice that used the glial fibrillary acidic protein promoter to target CIITA expression in astrocytes. CIITA was required for class II expression on astrocytes. Like class II-deficient mice, CIITA-deficient mice were resistant to EAE by immunization with CNS autoantigen, although T cells from immunized CIITA-deficient, but not class II-deficient, mice proliferated and secreted Th1 cytokines. CIITA-deficient splenic APC presented encephalitogenic peptide to purified wild-type encephalitogenic CD4(+) T cells, indicating that CIITA-independent mechanisms can be used for class II-restricted Ag presentation in lymphoid tissue. CIITA-deficient mice were also resistant to EAE by adoptive transfer of encephalitogenic class II-restricted CD4(+) Th1 cells, indicating that CIITA-dependent class II expression was required for CNS Ag presentation. Despite constitutive CIITA-driven class II expression on astrocytes in vivo, glial fibrillary acidic protein-CIITA transgenic mice were no more susceptible to EAE than controls. CIITA-transfected astrocytes presented peptide Ag, but in contrast to IFN-gamma-activated astrocytes, they could not process and present native Ag. CIITA-transfected astrocytes did not express cathepsin S without IFN-gamma activation, indicating that CIITA does not regulate other elements that may be required for Ag processing by astrocytes. Although our results demonstrate that CIITA-directed class II expression is required for EAE induction, CIITA-directed class II expression by astrocytes does not appear to increase EAE susceptibility. These results do not support the role of astrocytes as APC for class II-restricted Ag presentation during the induction phase of EAE.
Amino Acid Sequence↗
The HMG-CoA reductase inhibitor, atorvastatin, promotes a Th2 bias and reverses paralysis in central nervous system autoimmune disease.
Statins, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are approved for cholesterol reduction, may also be beneficial in the treatment of inflammatory diseases. Atorvastatin (Lipitor) was tested in chronic and relapsing experimental autoimmune encephalomyelitis, a CD4(+) Th1-mediated central nervous system (CNS) demyelinating disease model of multiple sclerosis. Here we show that oral atorvastatin prevented or reversed chronic and relapsing paralysis. Atorvastatin induced STAT6 phosphorylation and secretion of Th2 cytokines (interleukin (IL)-4, IL-5 and IL-10) and transforming growth factor (TGF)-beta. Conversely, STAT4 phosphorylation was inhibited and secretion of Th1 cytokines (IL-2, IL-12, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha) was suppressed. Atorvastatin promoted differentiation of Th0 cells into Th2 cells. In adoptive transfer, these Th2 cells protected recipient mice from EAE induction. Atorvastatin reduced CNS infiltration and major histocompatibility complex (MHC) class II expression. Treatment of microglia inhibited IFN-gamma-inducible transcription at multiple MHC class II transactivator (CIITA) promoters and suppressed class II upregulation. Atorvastatin suppressed IFN-gamma-inducible expression of CD40, CD80 and CD86 co-stimulatory molecules. l-Mevalonate, the product of HMG-CoA reductase, reversed atorvastatin's effects on antigen-presenting cells (APC) and T cells. Atorvastatin treatment of either APC or T cells suppressed antigen-specific T-cell activation. Thus, atorvastatin has pleiotropic immunomodulatory effects involving both APC and T-cell compartments. Statins may be beneficial for multiple sclerosis and other Th1-mediated autoimmune diseases.
Adoptive Transfer↗
Cutting edge: oral type I IFN-tau promotes a Th2 bias and enhances suppression of autoimmune encephalomyelitis by oral glatiramer acetate.
IFN-tau, a novel type I IFN that possesses immunomodulatory properties, lacks toxicity normally associated with other type I IFNs. We examined the effects of oral IFN-tau alone and in combination with oral glatiramer acetate in experimental allergic encephalomyelitis (EAE). By comparison of oral administration of IFN-alpha, -beta, and -tau to myelin basic protein-specific TCR-transgenic mice, we demonstrate these type I IFNs promote secretion of the Th2 cytokine IL-10 with similar efficiency. Whereas IFN-alpha and -beta induced IFN-gamma secretion, a Th1 cytokine, IFN-tau did not. Oral IFN-tau alone suppressed EAE. When suboptimal doses were administered orally in combination to wild-type mice, IFN-tau and glatiramer acetate had a synergistic beneficial effect in suppression of EAE. This combination was associated with TGF-beta secretion and enhanced IL-10 production. Thus, IFN-tau is a potential candidate for use as a single agent or in combination therapy for multiple sclerosis.
Adjuvants, Immunologic↗
Approved and future pharmacotherapy for multiple sclerosis.
BACKGROUND: Pharmacotherapy for relapsing-remitting multiple sclerosis (MS) advanced with the demonstration that interferon beta and glatiramer acetate improve the clinical course of this disease. Mitoxantrone is the first drug approved by the Food and Drug Administration for treatment of secondary progressive MS. Despite this progress, the agents presently available are only partially effective, are difficult to administer, and may have significant side effects. Several orally administered immunomodulatory agents are presently being evaluated for treatment of MS. One class of drugs, HMG CoA inhibitors (statins), is safe and well-tolerated and could become another mainstay of MS therapy. REVIEW SUMMARY: This article reviews the clinical evidence for approved MS therapies and discusses their mechanisms of action. Furthermore, the clinical and laboratory data suggesting a potential role for statins in MS therapy are discussed. CONCLUSIONS: Although treatment with interferon beta, glatiramer acetate, and mitoxantrone, the approved therapies, provide important treatment options for patients with relapsing-remitting MS and secondary progressive MS, the potential benefits of other medications, including statins, should be explored in controlled clinical trials.
Journal Article↗