Performance of the 2017 EULAR/ACR Classification Criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups: a scoping review.

The 2017 EULAR/ACR classification criteria for adult/juvenile idiopathic inflammatory myopathies (IIM) were established using a data-driven approach by an international group of myositis experts to allow classification of IIM and its major subtypes. Since their publication, the performance of the criteria has been tested in multiple cohorts worldwide and significant limitations have been identified. Moreover, the understanding and classification of IIM have evolved since 2017. This scoping review was undertaken as part of a large international project to revise the EULAR/ACR criteria and aims to i) summarise the evidence from the current literature on the performance characteristics of the 2017 EULAR/ACR classification criteria in various cohorts and IIM subtypes, and ii) delineate the factors that need to be considered in the revision of the classification criteria. A systematic search of Medline (via PubMed), Cumulative Index to Nursing and Allied Health Literature, and conference abstract archives was conducted independently by three investigators for studies on the EULAR/ACR criteria published between October 2017 and January 2023. This scoping review of 19 articles and 13 abstracts revealed overall good performance characteristics of the EULAR/ACR criteria for IIM, yet deficiencies in lack of inclusion of certain IIM subtypes, such as immune mediated necrotising myopathy, amyopathic dermatomyositis, antisynthetase syndrome and overlap myositis. Published modifications that may improve the performance characteristics of the criteria for classification of IIM subtypes were also summarised. The results of this review suggest that a revision of the EULAR/ACR criteria is warranted.

[Idiopathic inflammatory myopathies : An interdisciplinary challenge]. / Idiopathische inflammatorische Myopathien : Eine interdisziplinäre Herausforderung.

Idiopathic inflammatory myopathies (IIM) are rare diseases (incidence 1:100,000) with a wide range of clinical symptoms and manifestations. Typical indicators of IIM are proximally emphasized muscle weakness and myalgias, which are usually accompanied by elevated creatine kinase levels and muscle atrophy. The autoantibody diagnostics separate IIM into different entities, which are each associated with a typical risk of organ manifestations and the occurrence of tumors. The IIM represents an interdisciplinary challenge and the diagnostics and treatment require the involvement of several disciplines including rheumatology, neurology, neuropathology, dermatology and pneumology. An accurate diagnosis and careful tumor screening are essential because of the association between certain subgroups of IIM and the occurrence of malignant tumors.

[Expert recommendations for magnetic resonance imaging of muscle disorders]. / Expertenempfehlung zur Magnetresonanztomographie bei Muskelerkrankungen.

BACKGROUND: Magnetic resonance (MRI) imaging of the skeletal muscles (muscle MRI for short) is increasingly being used in clinical routine for diagnosis and longitudinal assessment of muscle disorders. However, cross-centre standards for measurement protocol and radiological assessment are still lacking. OBJECTIVES: The aim of this expert recommendation is to present standards for the application and interpretation of muscle MRI in hereditary and inflammatory muscle disorders. METHODS: This work was developed in collaboration between neurologists, neuroradiologists, radiologists, neuropaediatricians, neuroscientists and MR physicists from different university hospitals in Germany. The recommendations are based on expert knowledge and a focused literature search. RESULTS: The indications for muscle MRI are explained, including the detection and monitoring of structural tissue changes and oedema in the muscle, as well as the identification of a suitable biopsy site. Recommendations for the examination procedure and selection of appropriate MRI sequences are given. Finally, steps for a structured radiological assessment are presented. CONCLUSIONS: The present work provides concrete recommendations for the indication, implementation and interpretation of muscle MRI in muscle disorders. Furthermore, it provides a possible basis for the standardisation of the measurement protocols at all clinical centres in Germany.

Impact and Management of Dysphagia in Inflammatory Myopathies.

PURPOSE OF REVIEW: Dysphagia is a common symptom in inflammatory myopathies. This review provides an overview on the epidemiology, clinical impact, and management of dysphagia in myositis. Relevant diagnostic tools and treatment strategies are discussed. RECENT FINDINGS: Dysphagia can occur in any inflammatory myopathy, particularly in inclusion body myositis (IBM). It can lead to malnutrition or aspiration with subsequent pneumonia or even death. Dysphagia can be explored and monitored by patient-reported outcome scales for swallowing. New diagnostic tools such as real-time MRI and oro-pharyngo-esophageal scintigraphy have been studied for assessing dysphagia. Botulinum toxin injection can alleviate dysphagia in IBM. High-dose glucocorticosteroids are considered a first-line treatment for dysphagia in all other myositis subforms. Evaluation of dysphagia in myositis requires thorough clinical workup and appropriate instrumental procedures. Treatment options are available for dysphagia, but controlled trials and consensus on best patient care are required for this important symptom.

[Expert recommendations for magnetic resonance imaging of muscle disorders]. / Expertenempfehlung zur Magnetresonanztomographie bei Muskelerkrankungen.

BACKGROUND: Magnetic resonance (MRI) imaging of the skeletal muscles (muscle MRI for short) is increasingly being used in clinical routine for diagnosis and longitudinal assessment of muscle disorders. However, cross-centre standards for measurement protocol and radiological assessment are still lacking. OBJECTIVES: The aim of this expert recommendation is to present standards for the application and interpretation of muscle MRI in hereditary and inflammatory muscle disorders. METHODS: This work was developed in collaboration between neurologists, neuroradiologists, radiologists, neuropaediatricians, neuroscientists and MR physicists from different university hospitals in Germany. The recommendations are based on expert knowledge and a focused literature search. RESULTS: The indications for muscle MRI are explained, including the detection and monitoring of structural tissue changes and oedema in the muscle, as well as the identification of a suitable biopsy site. Recommendations for the examination procedure and selection of appropriate MRI sequences are given. Finally, steps for a structured radiological assessment are presented. CONCLUSIONS: The present work provides concrete recommendations for the indication, implementation and interpretation of muscle MRI in muscle disorders. Furthermore, it provides a possible basis for the standardisation of the measurement protocols at all clinical centres in Germany.

Antibody Therapies in Autoimmune Inflammatory Myopathies: Promising Treatment Options.

Inflammatory myopathies, including polymyositis (PM), dermatomyositis (DM), inclusion body myositis (IBM), necrotizing myopathy (NM), antisynthetase syndrome (ASS) and overlap myositis (OM), in short myositis, are rare diseases. All forms of myositis have progressive muscle weakness in common, with each subtype characterized by different autoantibody profiles, histological findings and extramuscular manifestations. Due to better understanding of the pathogenesis of the muscle inflammation in myositis, new molecular pathways for targeted therapy have been discovered. Current therapies aim at different components of the innate or the adaptive immune response. Additionally, non-inflammatory mechanisms in myositis have come into focus as possible treatment targets. The use of therapeutical antibodies in myositis has been examined in various clinical studies, several of them randomized controlled ones: Depletion of B-cells by rituximab has been established as treatment of refractory myositis. IVIG, an antibody therapy in the wider sense, has now been licensed for DM following a recent positive clinical trial. Negative study results were reported in randomized trials with infliximab, sifalimumab and bimagrumab. Studies on basiliximab and eculizumab are currently underway, and are expected to yield results in a couple of years. Despite some promising results of clinical studies with antibody therapy in myositis, further research is crucial to optimize the treatment for this debilitating disease and to find treatment alternatives for treatment-refractory patients.

Update on Myositis Therapy: From Today's Standards to Tomorrow's Possibilities.

Inflammatory myopathies, in short, myositis, are heterogeneous disorders that are characterized by inflammation of skeletal muscle and weakness of arms and legs. Research over the past few years has led to a new understanding regarding the pathogenesis of myositis. The new insights include different pathways of the innate and adaptive immune response during the pathogenesis of myositis. The importance of non-inflammatory mechanisms such as cell stress and impaired autophagy has been recently described. New target-specific drugs for myositis have been developed and are currently being tested in clinical trials. In this review, we discuss the mechanisms of action of pharmacological standards in myositis and provide an outlook of future treatment approaches.

Inflammatory myopathies: shedding light on promising agents and combination therapies in clinical trials.

INTRODUCTION: Due to new insights into the pathogenesis of inflammatory myopathies - in short myositis - and the urgent need for new treatment options in patients who are refractory to standard therapy, multiple novel drugs have been developed and studied in clinical trials. In light of this exciting development, a critical evaluation of the present data is necessary in order to identify the best pathway to future treatment of inflammatory myopathies. AREAS COVERED: This review focuses on the current evidence from clinical trials in myositis and encompasses dermatomyositis, polymyositis, necrotizing myopathy, antisynthetase-syndrome, overlap myositis, and inclusion body myositis. The results of studies on new therapeutic agents are summarized, in particular larger cohort studies and randomized trials from recent years. When such data were not available, earlier and smaller representative studies were included instead. EXPERT OPINION: Current studies in most myositis subtypes have shown positive effects of novel biologicals such as abatacept, sifalimumab, JAK-Inhibitors as well as known agents such as rituximab, but further studies are needed to confirm these observations. In inclusion body myositis, the eagerly awaited recent therapeutic trials have missed their primary endpoints, except for the phase 2 study with rapamycin, which has demonstrated significant improvements in secondary endpoints. Future trials will also need to focus on combination therapies of multiple immunomodulatory agents.

New insights into the treatment of myositis.

The myositis syndromes include polymyositis, dermatomyositis (DM), necrotizing myopathy, inclusion body myositis (IBM), antisynthetase syndrome and overlap syndromes with myositis. These syndromes mostly occur in middle-aged patients, while juvenile DM occurs in children and adolescents. Patients mostly show a subacute weakness and myalgia in the upper and lower limbs, the diagnosis is based upon these clinical findings in combination with muscle biopsy results and specific serum autoantibodies. In recent years, research achieved a better understanding about the molecular mechanism underlying the myositis syndromes, as well as disease progress and extramuscular organ manifestations, such as interstitial lung disease and association with neoplasias. Treatment mainly consists of glucocorticosteroids and immunosuppressants. IBM is usually refractory to treatments. This review provides an overview of the current standards of treatment and new treatment options like monoclonal antibodies and new molecular therapies and their first results from clinical trials.

Msp1 cooperates with the proteasome for extraction of arrested mitochondrial import intermediates.

The mitochondrial AAA ATPase Msp1 is well known for extraction of mislocalized tail-anchored ER proteins from the mitochondrial outer membrane. Here, we analyzed the extraction of precursors blocking the import pore in the outer membrane. We demonstrate strong genetic interactions of Msp1 and the proteasome with components of the TOM complex, the main translocase in the outer membrane. Msp1 and the proteasome both contribute to the removal of arrested precursor proteins that specifically accumulate in these mutants. The proteasome activity is essential for the removal as proteasome inhibitors block extraction. Furthermore, the proteasomal subunit Rpn10 copurified with Msp1. The human Msp1 homologue has been implicated in neurodegenerative diseases, and we show that the lack of the Caenorhabditis elegans Msp1 homologue triggers an import stress response in the worm, which indicates a conserved role in metazoa. In summary, our results suggest a role of Msp1 as an adaptor for the proteasome that drives the extraction of arrested and mislocalized proteins at the mitochondrial outer membrane.