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Query: UMLS:C0027121 (myositis)
 4,538 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The classification of idiopathic inflammatory myopathies has been refined with the characterization of new antibodies and their clinicopathological associations. The most widely used classification (Troyanov) defines pure polymyositis (PM) and dermatomyositis (DM), myositis overlap (presence of extra-muscular-extra-cutaneous manifestations or auto-antibodies), myositis associated to cancers and sporadic inclusion body myositis IBM). Overlap myositis are generally more severe and chronic than pure forms, and almost always require immunosuppressants. IBM remains difficult to treat, but immunosuppressants or immunoglobulins may be proposed, especially at the beginning of evolution.
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PMID:[Myositis: current data on the classification, diagnosis and treatment]. 1847 33

Besides the classical inflammatory myopathies (IM), dermatomyositis (DM), polymyositis, and inclusion body myositis, the much larger spectrum of IM includes focal and nodular myositis, granulomatous myositis, macrophagic myofasciitis, graft vs. host myositis, eosinophilic myositis, and other immune-associated conditions, some of them only recently described. In addition, paraneoplastic, statin-induced and critical illness myopathies have been considered immune-associated IM. Infectious, i.e., bacterial, viral, and parasitic IM are much less frequent in the northern hemisphere. In IM, muscle biopsy is an essential diagnostic procedure to initiate therapy. The myopathological spectrum encompasses disease-specific histopathological features, such as perifascicular atrophy in DM, non-necrotizing granulomas in sarcoid myopathy, autophagic vacuoles with tubulofilamentous inclusions in inclusion body myositis, rarely electron microscopic criteria, such as undulating tubules in endothelial cells of DM specimens, and, foremost, immunohistochemical findings. These latter features concern inflammatory infiltrates, the muscle parenchyma, the interstitial compartment, and the vasculature with varying involvement of each component in the different IM. Differences in immunohistochemical parameters among the IM, such as major histocompatibility complexes I and II, cytokines, cell adhesion molecules, different types of inflammatory cells, metalloproteinases, and complement factors procure a large gamut of data, the individual patterns of which characterize the myopathology of individual IM.
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PMID:Myopathology of non-infectious inflammatory myopathies - the current status. 1851 33

New classification of idiopathic inflammatory myopathy (IIM) defined three major entities, polymyositis (PM), dermatomyositis (DM) and sporadic inclusion body myositis (s-IBM). We report the clinical, electrophysiological and pathological characteristics of three patients with a rare form of IIM not fulfilling the diagnostic criteria for any of these three major entities. The three patients presented with a subacute, distal asymmetrical weakness in upper limbs. Muscle biopsy showed an active myositis, with necrosis and regeneration, T cell infiltrates with invasion of non-necrotic fibers, without rimmed vacuoles, and diffuse major histocompatibility complex-I (MHC-I) immunostaining in muscle fibers. All patients responded to immunosuppressive agents. Seven others cases were identified in the literature. It is important to recognize this atypical presentation as it seems to respond to immunosuppressive agents.
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PMID:Distal inflammatory myopathy: unusual presentation of polymyositis or new entity? 1853 49

Sporadic inclusion-body myositis (s-IBM) is the most common muscle disease of older persons. The muscle-fiber molecular phenotype exhibits similarities to both Alzheimer-disease (AD) and Parkinson-disease (PD) brains, including accumulations of amyloid-beta, phosphorylated tau, alpha-synuclein, and parkin, as well as evidence of oxidative stress and mitochondrial abnormalities. Early-onset autosomal-recessive PD can be caused by mutations in the DJ-1 gene, leading to its inactivation. DJ-1 has antioxidative and mitochondrial-protective properties. In AD and PD brains, DJ-1 is increased and oxidized. We studied DJ-1 in 17 s-IBM and 18 disease-control and normal muscle biopsies by: (1) immunoblots of muscle homogenates and mitochondrial fractions; (2) real-time PCR; (3) oxyblots evaluating DJ-1 oxidation; (4) light- and electron-microscopic immunocytochemistry. Compared to controls, in s-IBM muscle fibers DJ-1 was: (a) increased in the soluble fraction, monomer 2-fold (P = 0.01), and dimer 2.8-fold (P = 0.004); (b) increased in the mitochondrial fraction; (c) highly oxidized; and (d) aggregated in about 15% of the abnormal muscle fibers. DJ-1 mRNA was increased 3.5-fold (P = 0.034). Accordingly, DJ-1 might play a role in human muscle disease, and thus not be limited to human CNS degenerations. In s-IBM muscle fibers, DJ-1 could be protecting these fibers against oxidative stress, including protection of mitochondria.
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PMID:In inclusion-body myositis muscle fibers Parkinson-associated DJ-1 is increased and oxidized. 1860 99

In dermatomyositis (DM) there is strong histopathological evidence of a microvascular pathogenesis, including endothelial microtubular inclusions. In nonspecific myositis, perimysial and perivascular infiltrates in the muscle biopsy similar to DM are found. Microtubular inclusions in endothelial cells were systematically searched for and found in 4 of the 20 muscle biopsies of nonspecific myositis patients (20%). Three had a CTD (SLE, scleroderma, and Sjogren syndrome). Ten patients with DM and 5 patients with sporadic inclusion body myositis served as positive and negative controls, respectively.
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PMID:Tubuloreticular structures in different types of myositis: implications for pathogenesis. 1869 97

Ageing is thought to participate to the pathogenesis of sporadic inclusion-body myositis (s-IBM). Although the regenerative potential of s-IBM muscle is reduced in vivo, age-related abnormalities of satellite cells possibly accounting for the decline of muscle repair have not been demonstrated. Here we show that proliferation rate and clonogenicity of s-IBM myoblasts are significantly lower and doubling time is longer than normal age-matched controls, indicating that proliferative capacity of s-IBM muscles becomes exhausted earlier. Telomere shortening is detected in s-IBM cells suggesting premature senescence. Differently from controls, s-IBM myoblasts show increased active beta-catenin mainly localized within myonuclei, indicating active Wnt stimulation. After many rounds of muscle growth, only s-IBM myoblasts accumulate congophilic inclusions and immunoreactive Abeta(1-40) deposits. Therefore, s-IBM myoblasts seem to have a constitutively impaired regenerative capacity and the intrinsic property, upon sufficient aging in vitro, to accumulate Abeta. Our results might be valuable in understanding molecular mechanisms associated with muscle aging underlying the defective regeneration of s-IBM muscle and provide new clues for future therapeutic strategies.
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PMID:Increased aging in primary muscle cultures of sporadic inclusion-body myositis. 1882 81

SIRT1 belongs to the sirtuin family of NAD(+)-dependent histone/protein deacetylases. Experimentally, increased activity of SIRT1 facilitates calorie-restricted longevity, and decreases NF-kappaB activation and the amount of the amyloid-beta (Abeta). We studied SIRT1 in an aging-associated muscle disease, sporadic inclusion-body myositis (s-IBM), whose muscle fibers contain increased NF-kappaB activation and abnormal accumulation of Abeta. We show that, as compared to the age-matched controls, in s-IBM muscle fibers: (1) SIRT1 activity and deacetylation of SIRT1 targets, H4, NF-kappaB and p53 were decreased; (2) SIRT1 mRNA and protein were significantly increased; (3) in the cytoplasm, SIRT1 protein was accumulated in the form of cytoplasmic aggregates; (4) in the nuclei, SIRT1 protein was decreased. To our knowledge, this is the first demonstration of SIRT1 abnormalities, including decreased SIRT1 deacetylase activity, in human disease associated with aging. We propose that in s-IBM muscle fibers, inadequate activity of SIRT1 may be detrimental by increasing NF-kappaB activation and contributing to abnormal Abeta accumulation. Improving SIRT1 action by treatment with known SIRT1 activators might benefit s-IBM patients.
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PMID:Decreased SIRT1 deacetylase activity in sporadic inclusion-body myositis muscle fibers. 1892 3

Polymyositis (PM), dermatomyositis (DM) and sporadic inclusion body myositis (s-IBM) are severe inflammatory muscle disorders of unknown cause, which may present life-threatening complications. Prognosis and response to medications may be predicted not only from the clinical and pathologic diagnostic group into which a patient belongs, but also from the patient's myositis-specific antibody status, extraskeletal muscle involvement, and the interval between onset of muscle weakness, and the start of the treatment. Corticosteroids remain the mainstay of treatment in PM and DM. In patients refractory or intolerant to corticosteroids, another therapy, often an immunosuppressive agent, or intravenous immunoglobulin (IVIg), is added. IVIg seems the treatment of choice in severe myositis with dysphagia. New molecules, anti-TNF and monoclonal antibodies anti-CD20 justifies randomised trial and long term follow up.
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PMID:[Current therapy for polymyositis and dermatomyositis]. 1892 83

Sporadic inclusion-body myositis (s-IBM), the most common muscle disease of older persons, is of unknown cause and lacks successful treatment. Here we summarize diagnostic criteria and discuss our current understanding of the steps in the pathogenic cascade. While it is agreed that both degeneration and mononuclear-cell inflammation are components of the s-IBM pathology, how each relates to the pathogenesis remains unsettled. We suggest that the intra-muscle-fiber degenerative component plays the primary role, leading to muscle-fiber destruction and clinical weakness, since anti-inflammatory treatments are not of sustained benefit. We discuss possible treatment strategies aimed toward ameliorating a degenerative component, for example, lithium and resveratrol. Also discussed are the intriguing phenotypic similarities between s-IBM muscle fibers and the brains of Alzheimer and Parkinson's diseases, the most common neurodegenerative diseases associated with aging. Similarities include, in the respective tissues, cellular aging, mitochondrial abnormalities, oxidative and endoplasmic-reticulum stresses, proteasome inhibition and multiprotein aggregates.
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PMID:Inclusion-body myositis: muscle-fiber molecular pathology and possible pathogenic significance of its similarity to Alzheimer's and Parkinson's disease brains. 1897 94

We review our experience with needle muscle biopsy, including technique, results, complications, and outcome. We have collected data from 40 consecutive patients undergoing needle muscle biopsy of the quadriceps muscle. All biopsies were performed by the same operator and 98% were performed in the outpatient clinic. Specimens were sent to pathology for processing, staining, and interpretation. Follow-up clinical information was obtained by chart review. The ages of the patients ranged from 9 to 84 years, including three children. Of the 27 patients with a prebiopsy suspicion of idiopathic inflammatory myopathy (polymyositis, dermatomyositis, or inclusion body myositis) 13 had biopsies with consistent pathologic changes. Seven patients in this group had no pathologic diagnosis - none of these patients subsequently developed active myositis. Other conditions seen included mitochondrial myopathy, neuropathy, and type II fiber atrophy. Biopsies were very well tolerated, and no significant complications were seen. Therapeutic decisions were influenced most by needle muscle biopsy results obtained from patients suspected of having idiopathic inflammatory myopathy. Needle muscle biopsy charges were approximately 40% lower than those for open biopsies performed during the same interval. Needle muscle biopsy is a safe, care-effective, and cost-effective alternative to open muscle biopsy in the evaluation of a variety of myopathies.
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PMID:Needle muscle biopsy. 1907 26


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