fibrin and myelin-oligodendrocyte-glycoprotein-(35-55)

Multiple sclerosis (MS) is a neuroinflammatory disease characterized by demyelination and axonal damage of the central nervous system. The pathogenesis of MS has also been linked to vascular inflammation and local activation of the coagulation system, resulting in perivascular fibrin deposition. Treatment of experimental autoimmune encephalomyelitis (EAE), a model of human MS, with antithrombotic and antiinflammatory activated protein C (APC) reduces disease severity. Since recombinant APC (Drotecogin alfa), originally approved for the treatment of severe sepsis, is not available for human MS studies, we tested the hypothesis that pharmacologic activation of endogenous protein C could likewise improve the outcome of EAE. Mice were immunized with murine myelin oligodendrocyte glycoprotein (MOG) peptides and at the onset of EAE symptoms, were treated every other day with either WE thrombin (25 μg/kg; i.v.), a selective recombinant protein C activator thrombin analog, or saline control. Mice were monitored for changes in disease score until euthanized for ex vivo analysis of inflammation. Administration of WE thrombin significantly ameliorated clinical severity of EAE, reduced inflammatory cell infiltration and demyelination, suppressed the activation of macrophages comprising the CD11b + population and reduced accumulation of fibrin (ogen) in the spinal cord. These data suggest that symptomatic MS may respond to a treatment strategy that involves temporal pharmacological enhancement of endogenous APC generation.

Topics: Animals; Drug Evaluation, Preclinical; Encephalomyelitis, Autoimmune, Experimental; Enzyme Activation; Fibrin; Fibrinogen; Humans; Intercellular Adhesion Molecule-1; Macrophage Activation; Male; Mice; Multiple Sclerosis; Myelin-Oligodendrocyte Glycoprotein; Peptide Fragments; Point Mutation; Protein C; Spinal Cord; Spleen; Thrombin; Treatment Outcome; Tumor Necrosis Factor-alpha; White Matter

Although multiple sclerosis (MS) has been associated with the coagulation system, the temporal and spatial regulation of coagulation activity in neuroinflammatory lesions is unknown. Using a novel molecular probe, we characterized the activity pattern of thrombin, the central protease of the coagulation cascade, in experimental autoimmune encephalomyelitis. Thrombin activity preceded onset of neurological signs, increased at disease peak, and correlated with fibrin deposition, microglial activation, demyelination, axonal damage, and clinical severity. Mice with a genetic deficit in prothrombin confirmed the specificity of the thrombin probe. Thrombin activity might be exploited for developing sensitive probes for preclinical detection and monitoring of neuroinflammation and MS progression.

Topics: Animals; Axons; Blood Coagulation Factors; Connexin 30; Connexins; Demyelinating Diseases; Disease Models, Animal; Disease Progression; Encephalomyelitis, Autoimmune, Experimental; Fibrin; Green Fluorescent Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Myelin Basic Protein; Myelin-Oligodendrocyte Glycoprotein; Peptide Fragments; Poly I-C; Thrombin