losartan-potassium and myelin-oligodendrocyte-glycoprotein-(35-55)

Treatment with erythropoietin (Epo) in experimental autoimmune encephalomyelitis (EAE), the rodent model of multiple sclerosis (MS), has consistently been shown to ameliorate disease progression and improve overall outcome. The effect has been attributed to modulation of the immune response and/or preservation of the central nervous system (CNS) tissue integrity. It remains unclear, however, if (a) Epo acts primarily in the CNS or the periphery and if (b) Epo's beneficial effect in EAE is mainly due to maintaining CNS tissue integrity or to modulation of the immune response. If Epo acts primarily by modulating the immune system, where is this modulation required? In the periphery, the CNS or both?. To address these questions, we used two well-characterized transgenic mouse strains that constitutively overexpress recombinant human Epo (rhEpo) either systemically (tg6) or in CNS only (tg21) in a MOG-induced EAE model. We assessed clinical severity, disease progression, immunomodulation, and CNS tissue integrity, including neuronal survival.. Although disease onset remained unaffected, EAE progression was alleviated in transgenic animals compared to controls with both lines performing equally well showing that expression of Epo in the periphery is not required; Epo expression in the CNS is sufficient. Immunomodulation was observed in both strains but surprisingly the profile of modulation differed substantially between strains. Modulation in the tg21 strain was limited to a reduction in macrophages in the CNS, with no peripheral immunomodulatory effects observed. In contrast, in the tg6 strain, macrophages were upregulated in the CNS, and, in the periphery of this strain, T cells and macrophages were downregulated. The lack of a consistent immunomodulatory profile across both transgenic species suggests that immunomodulation by Epo is unlikely to be the primary mechanism driving amelioration of EAE. Finally, CNS tissue integrity was affected in all strains. Although myelin appeared equally damaged in all strains, neuronal survival was significantly improved in the spinal cord of tg21 mice, indicating that Epo may ameliorate EAE predominantly by protecting neurons.. Our data suggests that moderate elevated brain Epo levels provide clinically significant neuroprotection in EAE without modulation of the immune response making a significant contribution.

Topics: Animals; Central Nervous System; Cytokines; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Erythropoietin; Female; Gene Expression Regulation; Humans; Lymphocytes; Macrophages; Mice; Mice, Inbred C57BL; Mice, Transgenic; Monocytes; Myelin-Oligodendrocyte Glycoprotein; Neurons; Neuroprotection; Peptide Fragments; Proto-Oncogene Proteins c-sis; Spleen

Both erythropoietin (EPO) and haem oxygenase-1 (HO-1), an anti-oxidative stress protein, have proven protective roles in experimental autoimmune encephalomyelitis (EAE), a reliable animal model of multiple sclerosis. In this study, EPO delivered intraperitoneally could reduce disease severity in myelin oligodendrocyte glycoprotein (MOG)–EAE mice. To assess the effect of EPO on endogenous HO-1 in EAE, we investigated expression of HO-1 mRNA by real-time polymerase chain reaction (RT–PCR), protein expression centrally and peripherally by Western blot and immunohistochemistry and mean fluorescence intensity of splenic HO-1 by flow cytometry. A significantly higher expression of HO-1 in both the central nervous system (CNS) and spleen was shown in EPO-treated MOG–EAE mice than in controls.We further examined the immunomodulatory effect of EPO in EAE, and via RT–PCR demonstrated significantly lower expression of interferon-γ, interleukin (IL)-23, IL-6 and IL-17 mRNA, and significantly higher expression of IL-4 and IL-10 mRNA in CNS of EPO-treated MOG–EAE mice than in controls. Using flow cytometry, we also observed a significantly decreased ratio of both T helper type 1 (Th1) and Th17 lymphocyte subsets isolated from CNS and a significantly increased ratio of splenic regulatory CD4 T cells in EPO-treated MOG–EAE mice. In addition, we demonstrated that MOG-specific T cell proliferation was lower in the EPO-treated group than in controls and showed amelioration of EAE by adoptive transfer of splenocytes from EPO-treated MOG–EAE mice. Together, our data show that in EAE, EPO induction of endogenous HO-1 and modulation of adaptive immunity both centrally and peripherally may involve the repression of inflammatory responses.

Topics: Adoptive Transfer; Animals; Brain; Cell Count; Cell Proliferation; Cytokines; Encephalomyelitis, Autoimmune, Experimental; Epoetin Alfa; Erythropoietin; Gene Expression; Glycoproteins; Heme Oxygenase-1; Immunity, Cellular; Lymphocyte Activation; Membrane Proteins; Mice; Mice, Inbred C57BL; Myelin-Oligodendrocyte Glycoprotein; Peptide Fragments; Recombinant Proteins; Spinal Cord; Spleen; T-Lymphocytes, Regulatory; Th1 Cells; Th17 Cells; Th2 Cells

Erythropoietin (EPO) mediates a wide range of neuroprotective activities, including amelioration of disease and neuroinflammation in rat models of EAE. However, optimum dosing parameters are currently unknown. In the present study, we used a chronic EAE model induced in mice by immunization with the myelin oligodendrocyte glycoprotein peptide (MOG35-55) to compare the effect of EPO given with different treatment schedules. EPO was administered intraperitoneally at 0.5, 5.0 or 50 microg/kg three times weekly starting from day 3 after immunization (preventive schedule), at the onset of clinical disease (therapeutic schedule) or 15 days after the onset of symptoms (late therapeutic schedule). The results show that EPO is effective even when given after the appearance of clinical signs of EAE, but with a reduced efficacy compared to the preventative schedule. To determine whether this effect requires the homodimeric EPO receptor (EPOR2)-mediated hematopoietic effect of EPO, we studied the effect of carbamylated EPO (CEPO) that does not bind EPOR2. CEPO, ameliorated EAE without changing the hemoglobin concentration. Another non-erythropoietic derivative, asialoEPO was also effective. Both EPO and CEPO equivalently decreased the EAE-associated production of TNF-alpha, IL-1beta and IL-1Ra in the spinal cord, and IFN-gamma by peripheral lymphocytes, indicating that their action involves targeting neuroinflammation. The lowest dosage tested appeared fully effective. The possibility to dissociate the anti-neuroinflammatory action of EPO from its hematopoietic action, which may cause undesired side effects in non-anemic patients, present new avenues to the therapy of multiple sclerosis.

Topics: Analysis of Variance; Animals; Body Weight; Chronic Disease; Cytokines; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Encephalomyelitis, Autoimmune, Experimental; Erythropoietin; Female; Glycoproteins; Hematocrit; Humans; Immunohistochemistry; Mice; Mice, Inbred C57BL; Myelin-Oligodendrocyte Glycoprotein; Neuroprotective Agents; Peptide Fragments; Recombinant Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Severity of Illness Index; Spinal Cord; Spleen; Statistics, Nonparametric; Time Factors; Treatment Outcome; Tumor Necrosis Factor-alpha