Evidence of platelet activation in multiple sclerosis

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Interferon-β1a reduces plasma CD31+ endothelial microparticles (CD31+EMP) in multiple sclerosis

BACKGROUND: A correlation between plasma CD31+ endothelial microparticles (CD31+EMP) levels and clinical, as well as brain MRI activity, in multiple sclerosis (MS) patients has been previously reported. However, the effect(s) of treatment with interferon-β1a (IFN-β1a) on plasma levels of CD31+EMP has not been assessed. In a prospective study, we measured plasma CD31+EMP levels in 30 patients with relapsing-remitting MS. METHODS: Using flow cytometry, in a blinded study, we measured plasma CD31+EMP in 30 consecutive patients with relapsing-remitting MS (RRMS) prior to and 4, 12, 24 and 52 weeks after initiation of intramuscular therapy with interferon-β1a (IFN-β1a), 30 micrograms weekly. At each visit, clinical examination was performed and expanded disability status scale (EDSS) scores were assessed. RESULTS: Plasma levels of CD31+EMP were significantly reduced from 24 through 52 weeks following initiation of treatment with IFN-β1a. CONCLUSION: Our data suggest that serial measurement of plasma CD31+EMP levels may be used as a surrogate marker of response to therapy with INF-β1a. In addition, the decline in plasma levels of CD31+EMP further supports the concept that IFN-β1a exerts stabilizing effect on the cerebral endothelial cells in pathogenesis of MS

Inflammatory cytokines induce MAdCAM-1 in murine hepatic endothelial cells and mediate alpha-4 beta-7 integrin dependent lymphocyte endothelial adhesion In Vitro

<p>Abstract</p> <p>Background</p> <p>MAdCAM-1 plays a central role in T-lymphocyte homing to the gut, but its role in chronic liver inflammation remains unknown. Therefore, this study measured MAdCAM-1 expression, regulation, and function in cultured murine hepatic endothelial cells.</p> <p>Methods</p> <p>Cultures of hepatic endothelial cells (HEC) were prepared from mice expressing a temperature-sensitive SV40 large T antigen (<it>H-2K</it>^<it>b</it>-<it>tsA58</it>) under the control of an IFN-γ promoter. Time and dose dependent expression of MAdCAM-1 in response to TNF-α, IL-1β and IFN-γ was studied by immunoblotting. Lymphocyte adhesion was studied using α₄β₇integrin expressing lymphocytes (TK-1) +/- anti-MAdCAM-1 mAb.</p> <p>Results</p> <p>TNF-α induced MAdCAM-1 dose-and time-dependently with maximum expression at 20 ng/ml and at 48 hours. IL-1β also induced MAdCAM-1 to a lesser extent compared to TNF-α; IFN-γ did not induce MAdCAM-1. TNF-α significantly increased lymphocyte-endothelial adhesion (<it>P </it>< 0.01), which was reversed by anti-MAdCAM-1 antibody. MAdCAM-1 expression was also reduced by N-acetylcysteine and by two NO donors (SperNO, DETANO) suggesting that hepatic endothelial MAdCAM-1 is oxidant and NO regulated.</p> <p>Conclusion</p> <p>MAdCAM-1 is a major determinant of leukocyte recruitment in chronic inflammation and is expressed by HEC in response to IL-1β and TNF-α. This system may provide a useful model for studying inflammatory mechanisms in liver disease and help determine if controlled MAdCAM-1 expression might influence inflammation in liver disease.</p

Clinical and neuroimaging correlates of antiphospholipid antibodies in multiple sclerosis: a preliminary study

<p>Abstract</p> <p>Background</p> <p>The presence of antiphospholipid antibodies (APLA) in multiple sclerosis (MS) patients has been reported frequently but no clear relationship between APLA and the clinical and neuroimaging features of MS have heretofore been shown. We assessed the clinical and neuroimaging features of MS patients with plasma APLA.</p> <p>Methods</p> <p>A consecutive cohort of 24 subjects with relapsing-remitting (RR) MS were studied of whom 7 were in remission (Rem) and 17 in exacerbation (Exc). All subjects were examined and underwent MRI of brain. Patients' plasma was tested by standard ELISA for the presence of both IgM and IgG antibodies using a panel of 6 targets: cardiolipin (CL), β2 glycoprotein I (β2GPI), Factor VII/VIIa (FVIIa), phosphatidylcholine (PC), phosphatidylserine (PS) and phosphatidylethanolamine (PE).</p> <p>Results</p> <p>In exacerbation up to 80% of MS subjects had elevated titers of IgM antibodies directed against the above antigens. However, in remission, less than half of MS patients had elevated titers of IgM antibodies against one or more of the above antigens. This difference was significant, p < 0.01, for all 6 target antigens. Interestingly, none of the MS patients had elevated plasma titers of IgG against any of the target antigens tested. Correlation analysis between MRI enhancing lesions and plasma levels of APLA revealed high correlation for aPC, aPS and aFVIIa (p ≤ 0.0065), a trend for aPE and aCL (p = 0.056), and no correlation for aβ2GP1. The strongest correlation was for aFVIIa, p = 0.0002.</p> <p>Conclusion</p> <p>The findings of this preliminary study show that increased APLA IgM is associated with exacerbations of MS. Currently, the significance of this association in pathogenesis of MS remains unknown. However, systematic longitudinal studies to measure APLA in larger cohorts of patients with relapsing-remitting MS, particularly before and after treatment with immunomodulatory agents, are needed to confirm these preliminary findings.</p

Immunological assays for chemokine detection in in-vitro culture of CNS cells

Herein we review the various methods currently in use for determining the expression of chemokines by CNS cells in vitro. Chemokine detection assays are used in conjuction with one another to provide a comprehensive, biologically relevant assessment of the chemokines which is necessary for correct data interpretation of a specific observed biological effect. The methods described include bioassays for soluble chemokine receptors, RNA extraction, RT-PCR, Real - time quantitative PCR, gene array analysis, northern blot analysis, Ribonuclease Protection assay, Flow cytometry, ELISPOT, western blot analysis, and ELISA. No single method of analysis meets the criteria for a comprehensive, biologically relevant assessment of the chemokines, therefore more than one assay might be necessary for correct data interpretation, a choice that is based on development of a scientific rationale for the method with emphasis on the reliability and relevance of the method

Industrial methodology for process verification in research (IMPROVER): toward systems biology verification

Motivation: Analyses and algorithmic predictions based on high-throughput data are essential for the success of systems biology in academic and industrial settings. Organizations, such as companies and academic consortia, conduct large multi-year scientific studies that entail the collection and analysis of thousands of individual experiments, often over many physical sites and with internal and outsourced components. To extract maximum value, the interested parties need to verify the accuracy and reproducibility of data and methods before the initiation of such large multi-year studies. However, systematic and well-established verification procedures do not exist for automated collection and analysis workflows in systems biology which could lead to inaccurate conclusions

Melatonin reduces TNF-a induced expression of MAdCAM-1 via inhibition of NF-kB.

BACKGROUND: Endothelial MAdCAM-1 (mucosal addressin cell adhesion molecule-1) expression is associated with the oxidant-dependent induction and progress of inflammatory bowel disease (IBD). Melatonin, a relatively safe, potent antioxidant, has shown efficacy in several chronic injury models may limit MAdCAM-1 expression and therefore have a therapeutic use in IBD. METHODS: We examined how different doses of melatonin reduced endothelial MAdCAM-1 induced by TNF-a in an in vitro model of lymphatic endothelium. Endothelial monolayers were pretreated with melatonin prior to, and during an exposure, to TNF-a (1 ng/ml, 24 h), and MAdCAM-1 expression measured by immunoblotting. RESULTS: MAdCAM-1 was induced by TNF-a. Melatonin at concentrations over 100 μm (10(-4) M) significantly attenuated MAdCAM-1 expression and was maximal at 1 mM. CONCLUSIONS: Our data indicate that melatonin may exert therapeutic activity in IBD through its ability to inhibit NF-kB dependent induction of MAdCAM-1

RNase L Mediated Protection from Virus Induced Demyelination

IFN-α/β plays a critical role in limiting viral spread, restricting viral tropism and protecting mice from neurotropic coronavirus infection. However, the IFN-α/β dependent mechanisms underlying innate anti-viral functions within the CNS are poorly understood. The role of RNase L in viral encephalomyelitis was explored based on its functions in inhibiting translation, inducing apoptosis, and propagating the IFN-α/β pathway through RNA degradation intermediates. Infection of RNase L deficient (RL−/−) mice with a sub-lethal, demyelinating mouse hepatitis virus variant revealed that the majority of mice succumbed to infection by day 12 p.i. However, RNase L deficiency did not affect overall control of infectious virus, or diminish IFN-α/β expression in the CNS. Furthermore, increased morbidity and mortality could not be attributed to altered proinflammatory signals or composition of cells infiltrating the CNS. The unique phenotype of infected RL−/− mice was rather manifested in earlier onset and increased severity of demyelination and axonal damage in brain stem and spinal cord without evidence for enhanced neuronal infection. Increased tissue damage coincided with sustained brain stem infection, foci of microglia infection in grey matter, and increased apoptotic cells. These data demonstrate a novel protective role for RNase L in viral induced CNS encephalomyelitis, which is not reflected in overall viral control or propagation of IFN-α/β mediated signals. Protective function is rather associated with cell type specific and regional restriction of viral replication in grey matter and ameliorated neurodegeneration and demyelination

HDL Interfere with the Binding of T Cell Microparticles to Human Monocytes to Inhibit Pro-Inflammatory Cytokine Production

BACKGROUND: Direct cellular contact with stimulated T cells is a potent mechanism that induces cytokine production in human monocytes in the absence of an infectious agent. This mechanism is likely to be relevant to T cell-mediated inflammatory diseases such as rheumatoid arthritis and multiple sclerosis. Microparticles (MP) generated by stimulated T cells (MPT) display similar monocyte activating ability to whole T cells, isolated T cell membranes, or solubilized T cell membranes. We previously demonstrated that high-density lipoproteins (HDL) inhibited T cell contact- and MPT-induced production of IL-1beta but not of its natural inhibitor, the secreted form of IL-1 receptor antagonist (sIL-1Ra). METHODOLOGY/PRINCIPAL FINDINGS: Labeled MPT were used to assess their interaction with monocytes and T lymphocytes by flow cytometry. Similarly, interactions of labeled HDL with monocytes and MPT were assessed by flow cytometry. In parallel, the MPT-induction of IL-1beta and sIL-1Ra production in human monocytes and the effect of HDL were assessed in cell cultures. The results show that MPT, but not MP generated by activated endothelial cells, bond monocytes to trigger cytokine production. MPT did not bind T cells. The inhibition of IL-1beta production by HDL correlated with the inhibition of MPT binding to monocytes. HDL interacted with MPT rather than with monocytes suggesting that they bound the activating factor(s) of T cell surface. Furthermore, prototypical pro-inflammatory cytokines and chemokines such as TNF, IL-6, IL-8, CCL3 and CCL4 displayed a pattern of production induced by MPT and inhibition by HDL similar to IL-1beta, whereas the production of CCL2, like that of sIL-1Ra, was not inhibited by HDL. CONCLUSIONS/SIGNIFICANCE: HDL inhibit both MPT binding to monocytes and the MPT-induced production of some but not all cytokines, shedding new light on the mechanism by which HDL display their anti-inflammatory functions