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Essouma M. Autoimmune inflammatory myopathy biomarkers. Clin Chim Acta 2024; 553:117742. [PMID: 38176522 DOI: 10.1016/j.cca.2023.117742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 12/21/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024]
Abstract
The autoimmune inflammatory myopathy disease spectrum, commonly known as myositis, is a group of systemic diseases that mainly affect the muscles, skin and lungs. Biomarker assessment helps in understanding disease mechanisms, allowing for the implementation of precise strategies in the classification, diagnosis, and management of these diseases. This review examines the pathogenic mechanisms and highlights current data on blood and tissue biomarkers of autoimmune inflammatory myopathies.
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Affiliation(s)
- Mickael Essouma
- Network of Immunity in Infections, Malignancy and Autoimmunity, Universal Scientific Education and Research Network, Cameroon
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Hysa E, Cutolo CA, Gotelli E, Paolino S, Cimmino MA, Pacini G, Pizzorni C, Sulli A, Smith V, Cutolo M. Ocular microvascular damage in autoimmune rheumatic diseases: The pathophysiological role of the immune system. Autoimmun Rev 2021; 20:102796. [PMID: 33722750 DOI: 10.1016/j.autrev.2021.102796] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 01/13/2021] [Indexed: 02/07/2023]
Abstract
Pathological eye involvement represents a quite common finding in a broad spectrum of autoimmune rheumatic diseases (ARDs). Ocular signs, often occur as early manifestations in ARDs, ranging from symptoms related to the mild dry eye disease to sight-threatening pathologies, linked to the immune response against retinal and choroidal vessels. Retinovascular damage driven by markedly inflammatory reactivity need a prompt diagnosis and treatment. Immune-complexes formation, complement activation and antibody-mediated endothelial damage seem to play a key role, particularly, in microvascular damage and ocular symptoms, occurring in systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and Sjögren's syndrome (SS). Conversely, early alterations of retinal and choroidal vessels in the asymptomatic patient, often detectable coincidentally, might be indicators of widespread vascular injury in other connective tissue diseases. Particularly, endothelin-induced hypoperfusion and pathological peri-choroidal extracellular matrix deposition, might be responsible for the micro-architectural alterations and loss of capillaries detected in systemic sclerosis (SSc). Instead, interferon alpha-mediated microvascular rarefaction, combined with endothelial lesions caused by specific autoantibodies and immune-complexes, appear to play a significant role in retinal vasculopathy associated to inflammatory idiopathic myopathies (IIM). The immuno-pathophysiological mechanisms of ocular microcirculatory damage associated with the major ARDs will be discussed under the light of the most recent achievements.
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Affiliation(s)
- Elvis Hysa
- Laboratory of Experimental Rheumatology and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genoa, Italy - IRCCS Rheumatology Unit San Martino Polyclinic, Genoa, Italy.
| | - Carlo Alberto Cutolo
- Ophtalmology Clinic DiNOGMI, University of Genoa, IRCCS San Martino Polyclinic, Genoa, Italy.
| | - Emanuele Gotelli
- Laboratory of Experimental Rheumatology and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genoa, Italy - IRCCS Rheumatology Unit San Martino Polyclinic, Genoa, Italy.
| | - Sabrina Paolino
- Laboratory of Experimental Rheumatology and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genoa, Italy - IRCCS Rheumatology Unit San Martino Polyclinic, Genoa, Italy.
| | - Marco Amedeo Cimmino
- Laboratory of Experimental Rheumatology and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genoa, Italy - IRCCS Rheumatology Unit San Martino Polyclinic, Genoa, Italy.
| | - Greta Pacini
- Laboratory of Experimental Rheumatology and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genoa, Italy - IRCCS Rheumatology Unit San Martino Polyclinic, Genoa, Italy.
| | - Carmen Pizzorni
- Laboratory of Experimental Rheumatology and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genoa, Italy - IRCCS Rheumatology Unit San Martino Polyclinic, Genoa, Italy.
| | - Alberto Sulli
- Laboratory of Experimental Rheumatology and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genoa, Italy - IRCCS Rheumatology Unit San Martino Polyclinic, Genoa, Italy.
| | - Vanessa Smith
- Department of Internal Medicine, Ghent University, Ghent, Belgium; Department of Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, Ghent, Belgium; Unit for Molecular Immunology and Inflammation, VIB Inflammation Research Center (IRC), Corneel Heymanslaan 10, 9000 Ghent, Belgium.
| | - Maurizio Cutolo
- Laboratory of Experimental Rheumatology and Academic Division of Clinical Rheumatology, Department of Internal Medicine, University of Genoa, Italy - IRCCS Rheumatology Unit San Martino Polyclinic, Genoa, Italy.
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Notarnicola A, Barsotti S, Näsman L, Tang Q, Holmqvist M, Lundberg IE, Antovic A. Evaluation of risk factors and biomarkers related to arterial and venous thrombotic events in idiopathic inflammatory myopathies. Scand J Rheumatol 2021; 50:390-397. [PMID: 33622160 DOI: 10.1080/03009742.2020.1861647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Objectives: This study aimed to assess the contribution of traditional/disease-related risk factors and biomarkers linked to arterial and venous thrombotic events (TEs) in patients with idiopathic inflammatory myopathies (IIMs).Method: The occurrence of arterial and/or venous TEs at the time of or after IIM diagnosis was retrospectively evaluated in a cohort of 253 patients with IIMs, resulting in a final population of 246 IIM patients, 51 with reported TE (cases) and 195 without a history of TE (comparators). Information on disease characteristics and traditional risk factors for arterial and venous TE (essential hypertension, diabetes, dyslipidaemia, smoking, malignancy) was retrieved. Serum levels of anti-phospholipid antibodies (aPLs) and adhesion molecules were analysed at the time of IIM diagnosis and at the time of the TE in cases.Results: One in five IIM patients (21%) had experienced a TE, arterial TE in 22 and venous TE in 29 patients, with a peak prevalence within 5 years after diagnosis. Among traditional/disease-related risk factors, only older age was associated with both arterial and venous TEs, after adjusting for other covariates. Low serum levels of e-selectin were associated with higher odds of developing a TE, without specific association with either arterial or venous TEs. Only 6% of IIM patients had aPLs, with no significant difference between cases and comparators.Conclusions: An increased risk of both venous and arterial TEs should be considered in IIM patients, particularly close to diagnosis and in elderly people. Low serum levels of e-selectin may predict TE in IIM patients, but the underlying biological mechanism is not known.
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Affiliation(s)
- A Notarnicola
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet and Division of Rheumatology, Karolinska University Hospital, Stockholm, Sweden
| | - S Barsotti
- Rheumatology Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - L Näsman
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet and Division of Rheumatology, Karolinska University Hospital, Stockholm, Sweden
| | - Q Tang
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet and Division of Rheumatology, Karolinska University Hospital, Stockholm, Sweden
| | - M Holmqvist
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet and Division of Rheumatology, Karolinska University Hospital, Stockholm, Sweden.,Division of Clinical Epidemiology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - I E Lundberg
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet and Division of Rheumatology, Karolinska University Hospital, Stockholm, Sweden
| | - A Antovic
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet and Division of Rheumatology, Karolinska University Hospital, Stockholm, Sweden
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Mensch A, Zierz S. Cellular Stress in the Pathogenesis of Muscular Disorders-From Cause to Consequence. Int J Mol Sci 2020; 21:ijms21165830. [PMID: 32823799 PMCID: PMC7461575 DOI: 10.3390/ijms21165830] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/07/2020] [Accepted: 08/11/2020] [Indexed: 02/07/2023] Open
Abstract
Cellular stress has been considered a relevant pathogenetic factor in a variety of human diseases. Due to its primary functions by means of contractility, metabolism, and protein synthesis, the muscle cell is faced with continuous changes of cellular homeostasis that require rapid and coordinated adaptive mechanisms. Hence, a prone susceptibility to cellular stress in muscle is immanent. However, studies focusing on the cellular stress response in muscular disorders are limited. While in recent years there have been emerging indications regarding a relevant role of cellular stress in the pathophysiology of several muscular disorders, the underlying mechanisms are to a great extent incompletely understood. This review aimed to summarize the available evidence regarding a deregulation of the cellular stress response in individual muscle diseases. Potential mechanisms, as well as involved pathways are critically discussed, and respective disease models are addressed. Furthermore, relevant therapeutic approaches that aim to abrogate defects of cellular stress response in muscular disorders are outlined.
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Wernbom M, Schoenfeld BJ, Paulsen G, Bjørnsen T, Cumming KT, Aagaard P, Clark BC, Raastad T. Commentary: Can Blood Flow Restricted Exercise Cause Muscle Damage? Commentary on Blood Flow Restriction Exercise: Considerations of Methodology, Application, and Safety. Front Physiol 2020; 11:243. [PMID: 32265737 PMCID: PMC7098946 DOI: 10.3389/fphys.2020.00243] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/02/2020] [Indexed: 01/02/2023] Open
Affiliation(s)
- Mathias Wernbom
- Center for Health and Performance, Department of Food and Nutrition and Sport Science, University of Gothenburg, Gothenburg, Sweden
- Department of Health and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Brad J. Schoenfeld
- Department of Health Sciences, CUNY Lehman College, Bronx, NY, United States
| | - Gøran Paulsen
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Thomas Bjørnsen
- Department of Sport Science and Physical Education, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway
| | - Kristoffer T. Cumming
- Department of Sports, Physical Education and Outdoor Studies, Faculty of Humanities, Sports and Educational Science, University of South-Eastern Norway, Notodden, Norway
| | - Per Aagaard
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Brian C. Clark
- Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH, United States
- Department of Biomedical Sciences, Ohio University, Athens, OH, United States
| | - Truls Raastad
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
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Chen M, Quan C, Diao L, Xue F, Xue K, Wang B, Li X, Zhu X, Zheng J, Cao H. Measurement of cytokines and chemokines and association with clinical severity of dermatomyositis and clinically amyopathic dermatomyositis. Br J Dermatol 2018; 179:1334-1341. [PMID: 30101523 DOI: 10.1111/bjd.17079] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2018] [Indexed: 01/09/2023]
Affiliation(s)
- M. Chen
- Department of Dermatology; Rui Jin Hospital; School of Medicine; Shanghai Jiao Tong University; 200025 Shanghai China
| | - C. Quan
- Department of Dermatology; Rui Jin Hospital; School of Medicine; Shanghai Jiao Tong University; 200025 Shanghai China
| | - L. Diao
- Department of Dermatology; Rui Jin Hospital; School of Medicine; Shanghai Jiao Tong University; 200025 Shanghai China
| | - F. Xue
- Department of Dermatology; Rui Jin Hospital; School of Medicine; Shanghai Jiao Tong University; 200025 Shanghai China
| | - K. Xue
- Department of Dermatology; Rui Jin Hospital; School of Medicine; Shanghai Jiao Tong University; 200025 Shanghai China
| | - B. Wang
- Department of Dermatology; Rui Jin Hospital; School of Medicine; Shanghai Jiao Tong University; 200025 Shanghai China
| | - X. Li
- Department of Dermatology; Rui Jin Hospital; School of Medicine; Shanghai Jiao Tong University; 200025 Shanghai China
| | - X. Zhu
- Department of Respiratory Diseases; Rui Jin Hospital; School of Medicine; Shanghai Jiao Tong University; 200025 Shanghai China
| | - J. Zheng
- Department of Dermatology; Rui Jin Hospital; School of Medicine; Shanghai Jiao Tong University; 200025 Shanghai China
| | - H. Cao
- Department of Dermatology; Rui Jin Hospital; School of Medicine; Shanghai Jiao Tong University; 200025 Shanghai China
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Thøgersen KF, Simonsen JA, Hvidsten S, Gerke O, Jacobsen S, Høilund-Carlsen PF, Buch-Olsen KM, Diederichsen LP. Quantitative 3D scintigraphy shows increased muscular uptake of pyrophosphate in idiopathic inflammatory myopathy. EJNMMI Res 2017; 7:97. [PMID: 29222707 PMCID: PMC5722781 DOI: 10.1186/s13550-017-0348-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/28/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Nuclear imaging is increasingly being used in the diagnostic work-up of idiopathic inflammatory myopathy (IIM). Increased muscular uptake of technetium-99m-pyrophosphate (99mTc-PYP) has hitherto been assessed qualitatively by planar scintigraphy. We set out to perform quantitative tomographic scintigraphy in IIM. RESULTS Ninety IIM patients and 48 control subjects underwent 99mTc-PYP single-photon emission computed tomography (SPECT)/CT of the upper and lower body. Scans were evaluated visually by an intensity score (1-4) and quantitatively by the mean standardized uptake value (SUVmean) in thigh muscles after semi-automated segmentation of these. Furthermore, a SUVmean gradient down along the thighs was determined by linear regression of the slice-by-slice activity. Interobserver analyses were performed on qualitative evaluations. Compared to controls, patients more often had a high intensity score (p < 0.0001), but interobserver analyses revealed only moderate agreement. The thigh muscular 99mTc-PYP activity (SUVmean) was 60% higher in patients than in controls, p < 0.0001, albeit with a wide range. There was an activity gradient down the thigh muscle, the proximal tracer uptake being highest, and this gradient was steeper in patients than in controls; the activity decreased by 0.00024 and 0.00010 SUVmean mm-1, respectively, along the thighs. CONCLUSIONS The muscular uptake of 99mTc-PYP was significantly higher in patients than in healthy controls by qualitative and quantitative assessment. The tracer uptake was higher in the proximal than in the distal part of the thigh muscle, and SUVmean gradients differed between groups. Hence, tomographic nuclear imaging allowing for quantification of the 99mTc-PYP uptake might contribute to the diagnosis of IIM, and SPECT/CT of the lower body might suffice.
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Affiliation(s)
- Karin Folmer Thøgersen
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense, Denmark.,Department of Rheumatology, Odense University Hospital, Odense, Denmark
| | - Jane Angel Simonsen
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense, Denmark.
| | - Svend Hvidsten
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense, Denmark
| | - Oke Gerke
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense, Denmark.,Centre of Health Economics Research, University of Southern Denmark, Odense, Denmark
| | - Søren Jacobsen
- Copenhagen Lupus and Vasculitis Clinic, Center for Rheumatology and Spine Diseases, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Poul Flemming Høilund-Carlsen
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense, Denmark.,Clinical Institute, University of Southern Denmark, Odense, Denmark
| | | | - Louise Pyndt Diederichsen
- Department of Rheumatology, Odense University Hospital, Odense, Denmark.,Clinical Institute, University of Southern Denmark, Odense, Denmark
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Antiangiogenic VEGF isoform in inflammatory myopathies. Mediators Inflamm 2013; 2013:219313. [PMID: 23840094 PMCID: PMC3694558 DOI: 10.1155/2013/219313] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/01/2013] [Accepted: 05/15/2013] [Indexed: 11/18/2022] Open
Abstract
Objective. To investigate expression of vascular endothelial growth factor (VEGF) antiangiogenic isoform A-165b on human muscle in idiopathic inflammatory myopathies (IIM) and to compare distribution of angiogenic/antiangiogenic VEGFs, as isoforms shifts are described in other autoimmune disorders. Subjects and Methods. We analyzed VEGF-A165b and VEGF-A by western blot and immunohistochemistry on skeletal muscle biopsies from 21 patients affected with IIM (polymyositis, dermatomyositis, and inclusion body myositis) and 6 control muscle samples. TGF-β, a prominent VEGF inductor, was analogously evaluated. Intergroup differences of western blot bands density were statistically examined. Endomysial vascularization, inflammatory score, and muscle regeneration, as pathological parameters of IIM, were quantitatively determined and their levels were confronted with VEGF expression. Results. VEGF-A165b was significantly upregulated in IIM, as well as TGF-β. VEGF-A was diffusely expressed on unaffected myofibers, whereas regenerating/atrophic myofibres strongly reacted for both VEGF-A isoforms. Most inflammatory cells and endomysial vessels expressed both isoforms. VEGF-A165b levels were in positive correlation to inflammatory score, endomysial vascularization, and TGF-β. Conclusions. Our findings indicate skeletal muscle expression of antiangiogenic VEGF-A165b and preferential upregulation in IIM, suggesting that modulation of VEGF-A isoforms may occur in myositides.
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Loenneke JP, Thiebaud RS, Abe T, Manfro IG, Marin PJ. Acute blood flow restricted exercise to treat Duchenne muscular dystrophy: would it be efficacious? Front Physiol 2013; 4:114. [PMID: 23720637 PMCID: PMC3655283 DOI: 10.3389/fphys.2013.00114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 05/01/2013] [Indexed: 11/25/2022] Open
Affiliation(s)
- Jeremy P Loenneke
- Neuromuscular Research Laboratory, Department of Health and Exercise Science, The University of Oklahoma Norman, OK, USA
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Habers GEA, De Knikker R, Van Brussel M, Hulzebos E, Stegeman DF, Van Royen A, Takken T. Near-infrared spectroscopy during exercise and recovery in children with juvenile dermatomyositis. Muscle Nerve 2012; 47:108-15. [DOI: 10.1002/mus.23484] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2012] [Indexed: 11/11/2022]
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Ghirardello A, Zampieri S, Tarricone E, Iaccarino L, Gorza L, Doria A. Cutting edge issues in polymyositis. Clin Rev Allergy Immunol 2012; 41:179-89. [PMID: 21191666 DOI: 10.1007/s12016-010-8238-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Skeletal muscle is the target tissue of immunoflogistic processes in patients affected with idiopathic inflammatory myopathies (IIM). IIM are classified into three major forms: polymyositis (PM), dermatomyositis (DM), and inclusion body myositis. Recent data suggest that, in the major subsets of myositis, antigens in muscles drive a B-cell antigen-specific immune response. Moreover, some non-immunological mechanisms have been advocated. In this regard, an increased expression of Jo-1 and Mi-2 in muscle biopsies from PM and DM patients compared to normal muscle has been demonstrated; these candidate autoantigens in myositis are expressed at high levels in regenerating muscle cells rather than in mature myotubes. Myositis autoantigen upregulation has also been observed in neoplastic tissues, thus representing a potential link between cancer and autoimmunity in myositis. Myositis-specific autoantibodies (MSA) are disease markers and target intracellular proteins involved in key processes such as translocation and nuclear transcription. Myositis target antigens encompass aminoacyl-tRNA synthetases, the Mi-2 helicase/histone deacetylase protein complex, the signal recognition particle ribonucleoprotein, together with novel target antigens including p155/140, CADM-140, and SAE. Despite their high specificity for autoimmune myositis, MSA target non-muscle restricted proteins ubiquitary to all cell types, making the specific muscle involvement difficult to explain. Non-immunological mechanisms also seem to contribute to the pathogenesis of IIM; activation of endoplasmic reticulum stress response due to muscle regeneration and inflammation but independent to MHC-1 up-regulation has been recently reported in patients with myositis.
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Affiliation(s)
- Anna Ghirardello
- Division of Rheumatology, Department of Clinical and Experimental Medicine, University of Padova, Italy
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Gherardi RK. Pathogenic aspects of dermatomyositis, polymyositis and overlap myositis. Presse Med 2011; 40:e209-18. [PMID: 21376512 DOI: 10.1016/j.lpm.2010.12.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 12/17/2010] [Indexed: 12/11/2022] Open
Abstract
Inflammatory myopathies (IMs) often have distinct histopathologic features suggesting humorally mediated involvement of the microcirculation in dermatomyositis (DM), including early capillary deposition of the complement C5b-9 membranolytic attack complex (MAC) and secondary ischaemic changes; and CD8 T-cell-mediated and MHC1-restricted autoimmune attack of myofibers in polymyositis (PM) and inclusion body myositis. Novel insights in these specific diseases include emerging evidence that capillary loss involves whole microvascular units in DM, and that regulatory T-cells strongly protect myofibers from experimental autotoxic attack in PM. However, all IMs do not exhibit pathophysiology-relevant histopathologic features of DM or PM. Autoimmune necrotizing myopathies (AINM) occur in the absence of endomysial inflammatory cells and may be specifically associated with anti-SRP autoantibodies. Moreover, IM histopathological features may be scarce, unspecific and overlapping. Therefore, increasing attention is paid to features shared by IMs regardless of their type, relevant to the innate immune response and to non-immune mechanisms. Innate immune responses to myodamage (and/or as yet unknown stimuli), involves release of chemokines, activation of specific Toll-like receptors (TLRs) and complex Th-1, Th-17 and other cytokine interplays; it triggers DC recruitment and maturation, and is associated with type 1 IFN signature (especially in DM where type 1 IFN-producing cells called plasmacytoid DCs are mainly detected). Non-immune mechanisms mainly include endoplasmic reticulum (ER) stress induced in myofibers by up-regulation of MHC-class I antigens (as typically observed in PM with a diffuse pattern and in DM with perifascicular predominance). ER stress may favour autoimmune reactions but may also be associated with myofiber damage and dysfunction in the absence of lymphocytes. Overlap myositis (OM) may be associated with other connective tissue diseases and a variety of autoantibodies, such as those directed against tRNA synthetase. Myositis specific autoantibodies are mainly expressed by regenerating myofibers, that may also express MHC-1 and endogenous ligand-binding TLRs, thus drawing a picture in which the regenerating myofiber plays a central pathophysiologic role.
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Affiliation(s)
- Romain K Gherardi
- CHU Henri-Mondor, AP-HP, centre de référence des maladies neuromusculaires Garches-Necker_Mondor-Hendaye, service d'histologie, 94010 Créteil, France.
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Current world literature. Curr Opin Rheumatol 2010; 22:704-12. [PMID: 20881793 DOI: 10.1097/bor.0b013e3283404094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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