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- Laforet, P., et al.
(författare)
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Deep morphological analysis of muscle biopsies from type III glycogenesis (GSDIII), debranching enzyme deficiency, revealed stereotyped vacuolar myopathy and autophagy impairment
- 2019
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Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Glycogen storage disorder type III (GSDIII), or debranching enzyme (GDE) deficiency, is a rare metabolic disorder characterized by variable liver, cardiac, and skeletal muscle involvement. GSDIII manifests with liver symptoms in infancy and muscle involvement during early adulthood. Muscle biopsy is mainly performed in patients diagnosed in adulthood, as routine diagnosis relies on blood or liver GDE analysis, followed by AGL gene sequencing. The GSDIII mouse model recapitulate the clinical phenotype in humans, and a nearly full rescue of muscle function was observed in mice treated with the dual AAV vector expressing the GDE transgene. In order to characterize GSDIII muscle morphological spectrum and identify novel disease markers and pathways, we performed a large international multicentric morphological study on 30 muscle biopsies from GSDIII patients. Autophagy flux studies were performed in human muscle biopsies and muscles from GSDIII mice. The human muscle biopsies revealed a typical and constant vacuolar myopathy, characterized by multiple and variably sized vacuoles filled with PAS-positive material. Using electron microscopy, we confirmed the presence of large nonmembrane bound sarcoplasmic deposits of normally structured glycogen as well as smaller rounded sac structures lined by a continuous double membrane containing only glycogen, corresponding to autophagosomes. A consistent SQSTM1/p62 decrease and beclin-1 increase in human muscle biopsies suggested an enhanced autophagy. Consistent with this, an increase in the lipidated form of LC3, LC3II was found in patients compared to controls. A decrease in SQSTM1/p62 was also found in the GSDIII mouse model. In conclusion, we characterized the morphological phenotype in GSDIII muscle and demonstrated dysfunctional autophagy in GSDIII human samples. These findings suggest that autophagic modulation combined with gene therapy might be considered as a novel treatment for GSDIII.
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- Notarnicola, A., et al.
(författare)
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Autoantibodies against a subunit of mitochondrial respiratory chain complex I in inclusion body myositis
- 2023
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 82, s. 574-574
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Tidskriftsartikel (refereegranskat)abstract
- Background Autoantibodies are found in up to 80% of patients with idiopathic inflammatory myopathies (IIM) and are associated with distinct clinical phenotypes [1]. Autoantibodies targeting cytosolic 5´-nucleotidase 1A (anti-cN1A) are currently the only known serum biomarker for the subgroup inclusion body myositis (IBM) (2), although detected even in other autoimmune diseases.Objectives To identify new autoimmune targets in IIM by antigen bead array assay.Methods In a first cross-sectional exploratory study, 357 antigens representing 268 proteins were incubated with plasma samples from 219 IIM (108 Polymyositis (PM), 80 Dermatomyositis (DM) and 31 IBM) patients, 349 Systemic Lupus Erythematosus (SLE) patients and 306 population controls for screening of IgG reactivity by antigen bead array. All samples were identified in the local biobank of the Rheumatology clinic, Karolinska University Hospital. Interesting results obtained for the IBM subgroup were then validated in an independent larger cohort of 287 patients with IBM followed at nine European rheumatological or neurological centers. IBM serum samples were explored by antigen bead array and results validated by western blot. As controls, serum samples from 30 patients with PM and 30 with DM, HLA-matched with the IBM Swedish cohort, were included. Demographics, laboratory, clinical, and muscle biopsy data of the IBM cohort was retrieved.Results In the exploratory study IgG reactivity towards NADH dehydrogenase 1 α subcomplex 11 (NDUFA11), a subunit of the membrane-bound mitochondrial respiratory chain complex I, was discovered with higher frequency in the IBM (9,7%) than PM (2,8%) and DM samples (2,5%), although the difference was not statistically significant. Anti-NDUFA11 IgG was also found in 2,3% of SLE and 2,6% of population control samples. In the validation study anti-NDUFA11 autoantibodies were detected in 11/287 IBM patients (3,8%), 0/30 PM and 0/30 DM patients. Reactivity against NDUFA11 could be confirmed by western blot (Table 1, Figure 1). The eleven anti-NDUFA11 positive patients showed a trend of lower frequency of wheelchair/walker ever use and higher creatine kinase levels at time of IBM diagnosis compared to the anti-NDUFA11 negative group. Ragged red fibers were significantly more prevalent in anti-NDUFA11 positive than negative patients (p=0.04). Anti-cN1A autoantibodies were detected in 98/287 (34,1%) of IBM, 3/30 (10%) DM and 9/29 (31%) PM patients, p=0.03. Coexistence of anti NDUFA11 and anti-cN1A antibodies was observed in 3 IBM patients.Conclusion Our results reveal a new autoimmune target in the mitochondrial respiratory chain complex I that might be specifically associated with IBM. This is of particular interest as mitochondrial abnormalities are known histological findings in muscle biopsies of IBM patients.References [1]Galindo-Feria AS, Wang G, Lundberg IE. Autoantibodies: Pathogenic or epiphenomenon. Best Pract Res Clin Rheumatol. 2022;36(2):101767.[2]Herbert MK,et al. Disease specificity of autoantibodies to cytosolic 5’-nucleotidase 1A in sporadic inclusion body myositis versus known autoimmune diseases. Ann Rheum Dis. 2016;75(4):696-701.
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- Lilleker, JB, et al.
(författare)
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Cytosolic 5'-nucleotidase 1A autoantibody profile and clinical characteristics in inclusion body myositis
- 2017
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Ingår i: Annals of the rheumatic diseases. - : BMJ. - 1468-2060 .- 0003-4967. ; 76:5, s. 862-868
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Tidskriftsartikel (refereegranskat)abstract
- Autoantibodies directed against cytosolic 5′-nucleotidase 1A have been identified in many patients with inclusion body myositis. This retrospective study investigated the association between anticytosolic 5′-nucleotidase 1A antibody status and clinical, serological and histopathological features to explore the utility of this antibody to identify inclusion body myositis subgroups and to predict prognosis.Materials and methodsData from various European inclusion body myositis registries were pooled. Anticytosolic 5′-nucleotidase 1A status was determined by an established ELISA technique. Cases were stratified according to antibody status and comparisons made. Survival and mobility aid requirement analyses were performed using Kaplan-Meier curves and Cox proportional hazards regression.ResultsData from 311 patients were available for analysis; 102 (33%) had anticytosolic 5′-nucleotidase 1A antibodies. Antibody-positive patients had a higher adjusted mortality risk (HR 1.89, 95% CI 1.11 to 3.21, p=0.019), lower frequency of proximal upper limb weakness at disease onset (8% vs 23%, adjusted OR 0.29, 95% CI 0.12 to 0.68, p=0.005) and an increased prevalence of excess of cytochrome oxidase deficient fibres on muscle biopsy analysis (87% vs 72%, adjusted OR 2.80, 95% CI 1.17 to 6.66, p=0.020), compared with antibody-negative patients.InterpretationDifferences were observed in clinical and histopathological features between anticytosolic 5′-nucleotidase 1A antibody positive and negative patients with inclusion body myositis, and antibody-positive patients had a higher adjusted mortality risk. Stratification of inclusion body myositis by anticytosolic 5′-nucleotidase 1A antibody status may be useful, potentially highlighting a distinct inclusion body myositis subtype with a more severe phenotype.
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- Tawil, Rabi, et al.
(författare)
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Safety and efficacy of losmapimod in facioscapulohumeral muscular dystrophy (ReDUX4): a randomised, double-blind, placebo-controlled phase 2b trial
- 2024
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Ingår i: Lancet Neurology. - : ELSEVIER SCIENCE INC. - 1474-4422 .- 1474-4465. ; 23:5, s. 477-486
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Tidskriftsartikel (refereegranskat)abstract
- Background Facioscapulohumeral muscular dystrophy is a hereditary progressive myopathy caused by aberrant expression of the transcription factor DUX4 in skeletal muscle. No approved disease-modifying treatments are available for this disorder. We aimed to assess the safety and efficacy of losmapimod (a small molecule that inhibits p38 alpha MAPK, a regulator of DUX4 expression, and p38 beta MAPK) for the treatment of facioscapulohumeral muscular dystrophy. Methods We did a randomised, double-blind, placebo-controlled phase 2b trial at 17 neurology centres in Canada, France, Spain, and the USA. We included adults aged 18-65 years with type 1 facioscapulohumeral muscular dystrophy (ie, with loss of repression of DUX4 expression, as ascertained by genotyping), a Ricci clinical severity score of 2-4, and at least one skeletal muscle judged using MRI to be suitable for biopsy. Participants were randomly allocated (1:1) to either oral losmapimod (15 mg twice a day) or matching placebo for 48 weeks, via an interactive response technology system. The investigator, study staff, participants, sponsor, primary outcome assessors, and study monitor were masked to the treatment allocation until study closure. The primary endpoint was change from baseline to either week 16 or 36 in DUX4driven gene expression in skeletal muscle biopsy samples, as measured by quantitative RT-PCR. The primary efficacy analysis was done in all participants who were randomly assigned and who had available data for assessment, according to the modified intention-to-treat principle. Safety and tolerability were assessed as secondary endpoints. This study is registered at ClinicalTrials.gov, number NCT04003974. The phase 2b trial is complete; an open-label extension is ongoing. Findings Between Aug 27, 2019, and Feb 27, 2020, 80 people were enrolled. 40 were randomly allocated to losmapimod and 40 to placebo. 54 (68%) participants were male and 26 (33%) were female, 70 (88%) were White, and mean age was 45<middle dot>7 (SD 12<middle dot>5) years. Least squares mean changes from baseline in DUX4driven gene expression did not differ significantly between the losmapimod (0<middle dot>83 [SE 0<middle dot>61]) and placebo (0<middle dot>40 [0<middle dot>65]) groups (difference 0<middle dot>43 [SE 0<middle dot>56; 95% CI -1<middle dot>04 to 1<middle dot>89]; p=0<middle dot>56). Losmapimod was well tolerated. 29 treatment-emergent adverse events (nine drugrelated) were reported in the losmapimod group compared with 23 (two drug-related) in the placebo group. Two participants in the losmapimod group had serious adverse events that were deemed unrelated to losmapimod by the investigators (alcohol poisoning and suicide attempt; postoperative wound infection) compared with none in the placebo group. No treatment discontinuations due to adverse events occurred and no participants died during the study. Interpretation Although losmapimod did not significantly change DUX4-driven gene expression, it was associated with potential improvements in prespecified structural outcomes (muscle fat infiltration), functional outcomes (reachable workspace, a measure of shoulder girdle function), and patient-reported global impression of change compared with placebo. These findings have informed the design and choice of efficacy endpoints for a phase 3 study of losmapimod in adults with facioscapulohumeral muscular dystrophy.
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