Animal model dermatomyositis

The inflammatory myopathies are a group of quite proteiform, systemic auto-immune diseases which include polymyositis, dermatomyositis and inclusion body myopathies. To facilitate the diagnosis, classification criteria (Bohan and Peter, 1975) have been proposed, based essentially on clinical criteria. In addition, over the past fifteen years, auto-antibodies characterizing certain forms of inflammatory myopathy have been identified. One distinguishes schematically: auto-antibodies specific for myositis and auto-antibodies sometimes associated with myositis...

Vitamin D levels depend on many variables, including sun exposure, age, ethnicity, body mass index, use of medications and supplements. A much higher oral vitamin D intake than the current guidelines is necessary to maintain adequate circulating 25(OH)D levels in the absence of UVB radiation of the skin. In addition to the traditional known metabolic activities, vitamin D has been shown to modulate the immune system, and its deficiency has been linked to the development of several autoimmune disorders including type 1 diabetes and multiple sclerosis...

OBJECTIVE: Autoantibodies against the chromatin remodeler Mi-2 are found in a distinct subset of patients with dermatomyositis (DM). Previous quantitative immunoblotting experiments demonstrated that Mi-2 protein levels are up-regulated in DM muscle. This study was undertaken to define the population of cells expressing high levels of Mi-2 in DM muscle and to explore the regulation and functional role of Mi-2 during muscle regeneration. METHODS: The expression of Mi-2 was analyzed by immunofluorescence microscopy in human muscle biopsy specimens...

Idiopathic inflammatory myopathies (IIMs) are inflammatory disorders of unknown origin. On the basis of clinical, histopathological, and immunological features, they can be differentiated into three major and distinct subsets: dermatomyositis; polymyositis; and inclusion-body myositis. Although a few animal models for IIM are currently available, they lack several characteristic aspects of IIMs. The aim of our study was to examine skeletal muscle involvement in an experimental animal model of visceral leishmaniasis, a disseminated infection caused by the protozoan parasite Leishmania infantum, and to compare features of associated inflammation with those of human IIM...

OBJECTIVE: Polymyositis and dermatomyositis are chronic inflammatory muscle diseases. Retinoids are compounds that bind to the retinoic acid binding site of retinoic acid receptors and have biologic activities similar to those of vitamin A. Recent studies indicate that retinoids promote Th2 differentiation and suppress Th1 and Th17 differentiation in vitro. The present study was undertaken to examine the effects of a synthetic retinoid, Am80, on experimental autoimmune myositis as well as on Th phenotype development and antibody production...

PURPOSE OF REVIEW: There is increasing evidence of autoimmunity in dermatomyositis and polymyositis, with strong correlations between particular myositis-specific autoantibodies (MSAs) and clinical subsets. It is now clear that corresponding autoantigens are selectively targeted, have distinct adjuvant properties and are upregulated in target tissues, suggesting a role in disease pathogenesis. This review highlights recent findings including the identification of novel MSAs and studies investigating autoantigen properties and expression in both target tissues and tumours...

Folding and transport of proteins, such as major histocompatibility complex (MHC) class I, through the endoplasmic reticulum (ER) is tightly regulated in all cells, including muscle tissue, where the specialized ER sarcoplasmic reticulum is also critical to muscle fiber function. Overexpression of MHC class I protein is a common feature of many muscle pathologies including idiopathic myositis and can induce ER stress. However, there has been no comparison of the consequences of MHC overexpression in muscle at different ages...

Systemic autoimmune diseases, such as vasculitis and collagen diseases, are characterized by chronic inflammation. Mutual interrelationship between angiogenesis and chronic inflammation has already been demonstrated. The aim of the study was to examine the effect of sera from patients with systemic autoimmune diseases on angiogenesis induced by human mononuclear cells. The study population consisted of 43 patients with a systemic autoimmune disease associated with pulmonary manifestations, divided into three groups: 14 with Wegener's granulomatosis (WG), 13 with systemic sclerosis (SS), and 16 with collagen vascular diseases (CVD) such as rheumatoid arthritis, systemic lupus erythematosus, and dermatomyositis...

No abstract text is available yet for this article.

PURPOSE OF REVIEW: The etiology of the idiopathic inflammatory myopathies remains elusive. Delineation of pathogenic mechanisms in humans is hindered by the heterogeneity of different patient populations as well as the complexity and chronicity of the disease. Therefore, appropriate animal models are required to help clarify the immunopathogenesis of these disorders and to explore promising new therapies. The purpose of this review is to discuss recently published animal models in myositis, with a particular focus on idiopathic inflammatory myopathy...

A number of autoimmune disorders have been identified in which IVIg treatment may be beneficial. Evidence for the use of IVIg in inflammatory myopathies comes from controlled trials in dermatomyositis (DM) and sporadic-inclusion body myositis (s-IBM). In DM, muscle strength was increased and neuromuscular scores and skin rashes improved. Results for s-IBM have not been as encouraging as those observed for DM. Subsequently, IVIg should be recommended as a second-line therapy in DM and used for life-threatening dysphagia in s-IBM...

Myositis autoantibodies continue to be the subject of substantial interest, with several significant recent developments. Recent studies have emphasized that anti-Jo-1 or other antisynthetases can be associated with interstitial lung disease, even in the absence of myositis. Anti-Jo-1 autoantibody levels were shown to correlate with disease activity over time. Immunization of mice with anti-Jo-1 led to muscle and lung inflammation, reminiscent of human disease. The complexity of the antibody picture in myositis continues to increase...

In genetically predisposed individuals, viruses, bacteria, or parasitic infectious agents are suspected of inducing autoimmunity and/or exacerbating autoimmune rheumatic diseases (ARD) once self-tolerance is broken. Although direct evidence for this association is still lacking, numerous data from animal models as well as from humans support the hypothesis of a direct contribution of pathogens to the induction of several ARD. This review focuses on the possible role of infectious agents as triggers of autoimmunity in systemic lupus erythematosus, polymyositis-dermatomyositis, antiphospholipid antibody syndrome, and primary vasculitis...

The idiopathic inflammatory myopathies (IIM) represent a heterogeneous group of acquired muscle diseases. The three best-studied subgroups: dermatomyositis (DM), polymyositis (PM), and sporadic inclusion body myositis (IBM), differ considerably both clinically and pathophysiologically. DM is a chiefly humoral endotheliopathy often associated with characteristic skin manifestations. In PM and IBM nonnecrotic muscle fibers are invaded by auto-aggressive cytotoxic T-cells and macrophages. IBM presents with additional structural abnormalities of myofibers, including rimmed vacuoles and depositions of ectopic proteins...

Inflammatory myopathies are a group of autoimmune diseases that affect muscles. In humans, the most common inflammatory myopathies are polymyositis, dermatomyositis, and inclusion body myositis. Autoantibodies may be found in humans with inflammatory myopathies, and these play an important role in diagnosis and disease classification. However, these Abs are typically not muscle specific. Spontaneously occurring canine inflammatory myopathies may be good parallel disorders and provide insights into human myositis...

In genetically predisposed individuals, viruses, bacteria, or parasitic infectious agents are suspected to induce autoimmunity and/or to exacerbate the disease once the self-tolerance is broken. Although direct evidence for this association is still lacking, numerous data from animal models as well as from humans support the hypothesis of a direct contribution of pathogens to the induction of several autoimmune diseases. This review focused on the possible role of infectious agents as triggers of autoimmunity in polymyositis (PM) and dermatomyositis (DM)...

Accurate and rapid identification of perturbed pathways through the analysis of genome-wide expression profiles facilitates the generation of biological hypotheses. We propose a statistical framework for determining whether a specified group of genes for a pathway has a coordinated association with a phenotype of interest. Several issues on proper hypothesis-testing procedures are clarified. In particular, it is shown that the differences in the correlation structure of each set of genes can lead to a biased comparison among gene sets unless a normalization procedure is applied...

No abstract text is available yet for this article.

Alpha-dystroglycan is a cell surface peripheral membrane protein which binds to the extracellular matrix (ECM), while beta-dystroglycan is a type I integral membrane protein which anchors alpha-dystroglycan to the cell membrane via the N-terminal extracellular domain. The complex composed of alpha-and beta-dystroglycan is called the dystroglycan complex. We reported previously a matrix metalloproteinase (MMP) activity that disrupts the dystroglycan complex by cleaving the extracellular domain of beta-dystroglycan...

PURPOSE OF REVIEW: The idiopathic inflammatory myopathies (IIM) continue to provide a challenge given the variable effectiveness of the available treatments, and immunogenetic studies are ongoing to further elucidate IIM disease mechanisms. This review examines how recent research has improved our understanding of the mechanisms that lead to IIM. RECENT FINDINGS: HLA-DRB1 studies in a large homogenous cohort of UK Caucasian patients have confirmed that polymyositis (PM) and dermatomyositis (DM) are not genetically identical diseases while other studies have shown that tumor necrosis factor alpha is genetically implicated in disease susceptibility...