Relapsing-remitting multiple sclerosis: advances in disease-modifying therapies

Multiple sclerosis is a demyelinating disease affecting the central nervous system. It is the most prevalent disabling neurological condition among young adults, with onset typically between 20 and 40 years of age. Infiltrating immune cells and microglia activations are associated with inflammatory and neurodegenerative mechanisms. Current available disease modifying therapies suppress or modulate the immune system. These pharmaceuticals differ with respect to administration route and frequency, adverse effects, and efficacy. This paper provides a thorough manuscript illustrating the major prescribing factors, efficacy profiles, adverse events, and contraindications that patients and clinicians should consider while choosing a treatment. Despite the advancements made over the past 20 years, patients with progressive multiple sclerosis have few therapeutic options. Additionally, this paper assesses emerging therapies and disease targets on the pharmaceutical horizon, which have shown promise for all disease phenotypes

FTY720 (fingolimod) modulates the severity of viral-induced encephalomyelitis and demyelination.

BackgroundFTY720 (fingolimod) is the first oral drug approved by the Food and Drug Administration for treatment of patients with the relapsing-remitting form of the human demyelinating disease multiple sclerosis. Evidence suggests that the therapeutic benefit of FTY720 occurs by preventing the egress of lymphocytes from lymph nodes thereby inhibiting the infiltration of disease-causing lymphocytes into the central nervous system (CNS). We hypothesized that FTY720 treatment would affect lymphocyte migration to the CNS and influence disease severity in a mouse model of viral-induced neurologic disease.MethodsMice were infected intracranially with the neurotropic JHM strain of mouse hepatitis virus. Infected animals were treated with increasing doses (1, 3 and 10 mg/kg) of FTY720 and morbidity and mortality recorded. Infiltration of inflammatory virus-specific T cells (tetramer staining) into the CNS of FTY720-treated mice was determined using flow cytometry. The effects of FTY720 treatment on virus-specific T cell proliferation, cytokine production and cytolytic activity were also determined. The severity of neuroinflammation and demyelination in FTY720-treated mice was examined by flow cytometry and histopathologically, respectively, in the spinal cords of the mice.ResultsAdministration of FTY720 to JHMV-infected mice resulted in increased clinical disease severity and mortality. These results correlated with impaired ability to control viral replication (P < 0.05) within the CNS at days 7 and 14 post-infection, which was associated with diminished accumulation of virus-specific CD4+ and CD8+ T cells (P < 0.05) into the CNS. Reduced neuroinflammation in FTY720-treated mice correlated with increased retention of T lymphocytes within draining cervical lymph nodes (P < 0.05). Treatment with FTY720 did not affect virus-specific T cell proliferation, expression of IFN-γ, TNF-α or cytolytic activity. FTY720-treated mice exhibited a reduction in the severity of demyelination associated with dampened neuroinflammation.ConclusionThese findings indicate that FTY720 mutes effective anti-viral immune responses through impacting migration and accumulation of virus-specific T cells within the CNS during acute viral-induced encephalomyelitis. FTY720 treatment reduces the severity of neuroinflammatory-mediated demyelination by restricting the access of disease-causing lymphocytes into the CNS but is not associated with viral recrudescence in this model

Fingolimod modulates microglial activation to augment markers of remyelination

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Sphingosine 1-phosphate receptors: do they have a therapeutic potential in cardiac fibrosis?

Sphingosine 1-phosphate (S1P) is a bioactive lipid that is characterized by a peculiar mechanism of action. In fact, S1P, which is produced inside the cell, can act as an intracellular mediator, whereas after its export outside the cell, it can act as ligand of specific G-protein coupled receptors, which were initially named endothelial differentiation gene (Edg) and eventually renamed sphingosine 1-phosphate receptors (S1PRs). Among the five S1PR subtypes, S1PR1, S1PR2 and S1PR3 isoforms show broad tissue gene expression, while S1PR4 is primarily expressed in immune system cells, and S1PR5 is expressed in the central nervous system. There is accumulating evidence for the important role of S1P as a mediator of many processes, such as angiogenesis, carcinogenesis and immunity, and, ultimately, fibrosis. After a tissue injury, the imbalance between the production of extracellular matrix (ECM) and its degradation, which occurs due to chronic inflammatory conditions, leads to an accumulation of ECM and, consequential, organ dysfunction. In these pathological conditions, many factors have been described to act as pro- and anti-fibrotic agents, including S1P. This bioactive lipid exhibits both pro- and anti-fibrotic effects, depending on its site of action. In this review, after a brief description of sphingolipid metabolism and signaling, we emphasize the involvement of the S1P/S1PR axis and the downstream signaling pathways in the development of fibrosis. The current knowledge of the therapeutic potential of S1PR subtype modulators in the treatment of the cardiac functions and fibrinogenesis are also examined

Fingolimod for Multiple Sclerosis: Mechanism of Action, Clinical Outcomes, and Future Directions

The oral sphingosine 1-phosphate receptor (S1PR) modulator fingolimod functionally antagonizes S1PR hereby blocking lymphocyte egress from secondary lymphoid organs to the peripheral blood circulation. This results in a reduction in peripheral lymphocyte counts, including potentially encephalitogenic T cells. In patients with relapsing multiple sclerosis fingolimod has been shown to be an effective treatment. In phase 2 and phase 3 studies fingolimod-treated patients had reduced disease activity clinically and in MRI. Although severe infectious complications occurred in single cases treated with fingolimod, the frequency of overall infections was comparable in fingolimod-treated patients and controls. Overall, in clinical studies fingolimod was well tolerated and had a favorable safety profile. In follow-up studies with continuous fingolimod, treatment showed sustained efficacy while being well tolerate