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Sha Q, Zhang Z, Li H, Xu Y, Wang J, Du A. Serum metabolomic profile of myasthenia gravis and potential values as biomarkers in disease monitoring. Clin Chim Acta 2024; 562:119873. [PMID: 39019424 DOI: 10.1016/j.cca.2024.119873] [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: 03/31/2024] [Revised: 07/10/2024] [Accepted: 07/12/2024] [Indexed: 07/19/2024]
Abstract
OBJECTIVE Serum metabolites from 19 myasthenia gravis (MG) patients and 15 normal controls were analyzed via untargeted metabolomics, including 6 pre/post-treatment paired MG patients, to assess the value of serum metabolites as biomarkers in monitoring MG. METHOD Differential metabolites between MG patients and normal controls were identified through liquid and gas chromatography-mass spectrometry simultaneously. Principal component analysis and orthogonal partial least squares-discriminant analysis were conducted to identify the differential metabolites. Candidate metabolites and pathways associated with MG were selected through a random forest machine learning model. RESULT A total of 310 differential metabolites were identified with a threshold of variable projected importance > 1 and P value < 0.05. Among these, 158 metabolites were upregulated and 152 were downregulated. The random forest machine learning model selected 5 metabolites as potential biomarkers associated with MG: lignoceric acid (AUC=0.944), uridine diphosphate-N-acetylglucosamine (AUC=0.951), arachidonic acid (AUC=0.951), beta-glycerophosphoric acid (AUC=0.933), and L-Asparagine (AUC=0.877). Further analysis using 6 paired MG patients pre- and post-immunosuppression treatment revealed 25 upregulated and 6 downregulated metabolites in post-treatment serum, which might be relevant to disease intervention. The significance remains elusive due to the limited number of patients. CONCLUSION A subset of differential metabolites was identified in the serum of MG patients, some of which changed with immunosuppressive therapy. Small molecule metabolites may serve as valuable biomarkers for disease monitoring in MG.
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Affiliation(s)
- Qianqian Sha
- Department of Neurology, Songjiang Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 201699, China; Hongqiao International Institute of Medicine, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200336, China
| | - Zhongxiao Zhang
- Hongqiao International Institute of Medicine, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200336, China
| | - Hailong Li
- Department of Neurology, Songjiang Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 201699, China
| | - Yingchen Xu
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Jie Wang
- Hongqiao International Institute of Medicine, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200336, China
| | - Ailian Du
- Department of Neurology, Songjiang Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 201699, China; Hongqiao International Institute of Medicine, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200336, China.
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Jameie M, Amanollahi M, Ahli B, Farahmand G, Magrouni H, Sarraf P. Coexistence of myasthenia gravis and lichen planus: A case report and systematic review of related case reports from 1971 to 2024. Clin Case Rep 2024; 12:e9065. [PMID: 38883218 PMCID: PMC11177179 DOI: 10.1002/ccr3.9065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/03/2024] [Accepted: 05/31/2024] [Indexed: 06/18/2024] Open
Abstract
Key Clinical Message The co-occurrence of myasthenia gravis (MG) and lichen planus (LP) is a rare phenomenon, with only 13 cases reported in the English literature between 1971 and 2024. Patients with MG or LP, regardless of the thymoma status, require close monitoring for other autoimmune diseases. Abstract Myasthenia gravis (MG) is an uncommon autoimmune disease, resulting in fatigable muscle weakness in the ocular, bulbar, and respiratory muscles, as well as muscles of the extremities. Lichen planus (LP) is an autoimmune mucocutaneous disease, presenting with pruritic and violaceous plaques on the skin and mucosal surfaces. So far, MG and LP co-occurrence is only reported in anecdotal individuals. This study reports a patient with MG and LP and systematically reviews the English literature on this rare co-occurrence from 1971 to 2024, indicating only 13 cases with similar conditions. A 67-year-old man presented with ocular and progressive bulbar symptoms, a year after being diagnosed with generalized LP. Laboratory evaluations were normal except for the high anti-AchR-Ab titer and a positive ANA titer. Neurologic examinations revealed asymmetric bilateral ptosis, weakness and fatigability in proximal muscles, and a severe reduction in the gag reflex. He was diagnosed with late-onset, seropositive MG. The treatment included pyridostigmine (60 mg, three times daily), intravenous immunoglobulin (25 g daily for 5 days), and oral prednisolone. There was no evidence of thymoma in the chest x-ray and CT scan without contrast. However, a CT scan with contrast was not performed due to the patient's unstable condition. A common autoimmune mechanism may underlie the unclear pathophysiology of MG and LP co-occurrence, with or without thymoma. Patients with MG, LP, or thymoma require close monitoring and assessment for other possible autoimmune diseases.
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Affiliation(s)
- Melika Jameie
- Iranian Center of Neurological Research, Neuroscience Institute Tehran University of Medical Sciences Tehran Iran
| | - Mobina Amanollahi
- School of Medicine Tehran University of Medical Sciences Tehran Iran
| | - Bahareh Ahli
- School of Medicine Tehran University of Medical Sciences Tehran Iran
| | - Ghasem Farahmand
- Neurology Department, Imam Khomeini Hospital Complex Tehran University of Medical Sciences Tehran Iran
| | - Hana Magrouni
- Neurology Department, Imam Khomeini Hospital Complex Tehran University of Medical Sciences Tehran Iran
| | - Payam Sarraf
- Iranian Center of Neurological Research, Neuroscience Institute Tehran University of Medical Sciences Tehran Iran
- Neurology Department, Imam Khomeini Hospital Complex Tehran University of Medical Sciences Tehran Iran
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Zhao XL, Zheng YL, Yang CL, Wang JY, Liu Y, Du T, Zhao ZY, Duan RS, Li XL. Myasthenia gravis with tongue muscle atrophy: A case series. Heliyon 2024; 10:e30015. [PMID: 38707411 PMCID: PMC11066395 DOI: 10.1016/j.heliyon.2024.e30015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 04/07/2024] [Accepted: 04/18/2024] [Indexed: 05/07/2024] Open
Abstract
Here, we presented 6 patients who were admitted to our institution and diagnosed as myasthenia gravis (MG) with tongue muscle atrophy. All these 6 patients developed symptoms of bulbar muscle weakness in acetylcholine receptor antibodies positive MG (AChR-MG) (3/6), muscle-specific receptor tyrosine kinase antibodies positive MG (MuSK-MG) (1/6), and sero-negative MG (2/6). Most of patients had "triple-furrowed" tongue except for patient 2 with irregular atrophy of tongue muscle. Tongue muscle atrophy occurs in patients with MuSK-MG, AChR-MG, and sero-negative MG. Atrophied tongue muscles of five patients with MG were reversible after immunotherapy.
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Affiliation(s)
- Xue-Lu Zhao
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, PR China
| | - Yue-Liang Zheng
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, PR China
| | - Chun-Lin Yang
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, PR China
- Shandong Institute of Neuroimmunology, Jinan, 250014, PR China
- Shandong Provincial Medicine and Health Key Laboratory of Neuroimmunology, Jinan, 250014, PR China
| | - Jun-Yan Wang
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, PR China
| | - Ying Liu
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, PR China
- Shandong Institute of Neuroimmunology, Jinan, 250014, PR China
- Shandong Provincial Medicine and Health Key Laboratory of Neuroimmunology, Jinan, 250014, PR China
| | - Tong Du
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, PR China
- Shandong Institute of Neuroimmunology, Jinan, 250014, PR China
- Shandong Provincial Medicine and Health Key Laboratory of Neuroimmunology, Jinan, 250014, PR China
| | - Ze-Yu Zhao
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, PR China
| | - Rui-Sheng Duan
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, PR China
- Shandong Institute of Neuroimmunology, Jinan, 250014, PR China
- Shandong Provincial Medicine and Health Key Laboratory of Neuroimmunology, Jinan, 250014, PR China
| | - Xiao-Li Li
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, PR China
- Shandong Institute of Neuroimmunology, Jinan, 250014, PR China
- Shandong Provincial Medicine and Health Key Laboratory of Neuroimmunology, Jinan, 250014, PR China
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Mathis S, Solé G, Damon-Perrière N, Rouanet-Larrivière M, Duval F, Prigent J, Nadal L, Péréon Y, Le Masson G. Clinical Neurology in Practice: The Tongue (Part 1). Neurologist 2023; 28:338-348. [PMID: 37639535 DOI: 10.1097/nrl.0000000000000512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
BACKGROUND The tongue is an essential organ for the development of certain crucial functions, such as swallowing and language. The examination of the tongue can be very useful in neurology, as the various types of lingual alterations can lead to certain specific diagnoses, the tongue being a kind of "mirror" of some neurological function. REVIEW SUMMARY In this study, we reviewed the literature on anatomy, physiology, and the various aspects of the examination of the tongue. CONCLUSIONS Examination of the tongue should be an integral part of the clinical examination of the cranial nerves. This study aimed to demonstrate the importance of tongue motor and non-motor functions in neurological practice.
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Affiliation(s)
- Stéphane Mathis
- Department of Neurology, Muscle-Nerve
- Referral Center for Neuromuscular Diseases 'AOC'
- ALS Center
| | - Guilhem Solé
- Department of Neurology, Muscle-Nerve
- Referral Center for Neuromuscular Diseases 'AOC'
| | - Nathalie Damon-Perrière
- Department of Clinical Neurophysiology
- Department of Movement Disorders, University Hospitals of Bordeaux (CHU Bordeaux, Amélie Raba-Léon, Bordeaux
| | | | - Fanny Duval
- Department of Neurology, Muscle-Nerve
- Referral Center for Neuromuscular Diseases 'AOC'
| | | | | | - Yann Péréon
- Reference Centre for Neuromuscular Diseases 'AOC'. Filenemus, Euro-NMD, University Hospitals of Nantes (CHU Nantes), Nantes, France
| | - Gwendal Le Masson
- Department of Neurology, Muscle-Nerve
- Referral Center for Neuromuscular Diseases 'AOC'
- ALS Center
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5
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Birnbaum S, Sharshar T, Ropers J, Portero P, Hogrel JY. Neuromuscular fatigue in autoimmune myasthenia gravis: A cross-sectional study. Neurophysiol Clin 2023; 53:102844. [PMID: 36827843 DOI: 10.1016/j.neucli.2023.102844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 02/24/2023] Open
Abstract
OBJECTIVES To investigate the presence of increased neuromuscular fatigue (NMF) in individuals with myasthenia gravis (IwMG), compared to healthy controls. A secondary aim was to assess associations between NMF, strength and perceived health-related quality of life (HRQoL) and symptom severity in IwMG. METHODS In this cross-sectional study, we assessed NMF using classical myoelectrical indicators (root mean square: RMS, mean power frequency: MPF) obtained from surface electromyography (sEMG) during a sustained submaximal isometric contraction of the right Biceps Brachii and the right Vastus Lateralis and by evaluating the post-effort decline in peak torque following a fatiguing task consisting of a 40-second sustained isometric contraction. Relationships with MG-specific clinical scores (Myasthenia Muscle Score for symptom severity, MGQOL-15-F for HRQoL) were investigated. RESULTS Forty-one females with MG were compared to 18 control females of similar age. IwMG demonstrated reduced strength in both muscle groups, compared to control subjects. In both populations and both limbs, NMF was demonstrated by an increase in RMS and a decrease in MPF. However, IwMG did not demonstrate greater NMF based on these myoelectrical indicators nor based on post-effort peak torque decline. DISCUSSION Despite a decrease in baseline strength, IwMG did not display greater NMF in this specific experimental paradigm. This cohort consisted of individuals with mild-to-moderately severe MG which was well-controlled and stable. Further studies are warranted to identify simple and reliable methods to measure NMF in MG and to understand the relationship between NMF and perceived fatigue in activities of daily living for IwMG.
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Affiliation(s)
- Simone Birnbaum
- Neuromuscular Physiology and Evaluation Laboratory, Neuromuscular Investigation Center, Institute of Myology, Pitié-Salpêtrière University Hospital, 75651 Paris Cedex 13, France.
| | - Tarek Sharshar
- Anaesthesiology and ICU department, GHU-Psychiatry & Neurosciences, Sainte-Anne Hospital, Université Paris Cité, Institute of Psychiatry and Neurosciences of Paris, INSERM U1266, Paris, France
| | - Jacques Ropers
- Clinical Research Unit, Pitié-Salpêtrière University Hospital, APHP, 47-83 Bd de l'Hôpital, 75013, Paris, France
| | - Pierre Portero
- Bioingénierie, Tissus et Neuroplasticité, EA 7377 Université Paris-Est Créteil, Faculté de Médecine, 8 rue Jean Sarrail, 94010 Créteil, France
| | - Jean-Yves Hogrel
- Neuromuscular Physiology and Evaluation Laboratory, Neuromuscular Investigation Center, Institute of Myology, Pitié-Salpêtrière University Hospital, 75651 Paris Cedex 13, France
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Stascheit F, Aigner A, Mergenthaler P, Hotter B, Hoffmann S, Lehnerer S, Meisel C, Meisel A. Serum neurofilament light chain in myasthenia gravis subgroups: An exploratory cohort and case-Control study. Front Neurol 2023; 13:1056322. [PMID: 36712429 PMCID: PMC9875128 DOI: 10.3389/fneur.2022.1056322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/22/2022] [Indexed: 01/13/2023] Open
Abstract
Background This study aimed to evaluate the association of neurofilament light chain (Nfl) with neuromuscular destruction and disease severity in the serum of patients with myasthenia gravis (MG). Materials and methods Sera from 134 patients with MG with varying degrees of disease severity and autoantibody (Abs) status were analyzed and compared to controls in a cross-sectional design. Prospectively, we additionally measured serum NfL (sNfl) levels in patients with MG longitudinally for up to 3 years. Based on linear regression, differences between patients and controls were assessed. With correlation coefficients and mixed linear regression, the association among sNfl levels, socio-demographics, disease activity (Quantitative Myasthenia Gravis (QMG) score and Myasthenia Gravis Activities of Daily Living (MG-ADL) scale), Abs-status (acetylcholine receptor antibody (AChR-Abs), muscle-specific receptor tyrosine kinase antibody (MuSK-Abs), lipoprotein-related protein 4 (LRP4), and seronegative), Abs titer, treatment regime (pyridostigmine, steroids, and immunosuppressive therapies), and thymectomy were investigated. Results sNfl levels were higher in patients with MG compared to controls (median: 11.2 vs. 7.88), where sNfl levels were highest in anti-AChR-Abs positive patients (median 12.6), followed by anti-MuSK-Abs positive, anti-LRP4-Abs positive, and seronegative patients. Adjusting for age and sex, sNfl levels of patients with MG were on average 35% higher compared to controls (35.1, 95% CI: 8.4;68.3) and highest for patients with seronegative MG (44.35; 95% CI 16.47; 78.90). We found no relevant relationship between individual changes in sNfl and changes in QMG and MG-ADL scores. Conclusion sNfl levels are higher in patients with MG than in controls but were not consistently associated with clinical severity. Thus, sNfl is not a suitable biomarker to monitor individual disease progression in patients with MG.
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Affiliation(s)
- Frauke Stascheit
- Department of Neurology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany,NeuroCure Clinical Research Center, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany,*Correspondence: Frauke Stascheit ✉
| | - Annette Aigner
- Institute of Biometry and Clinical Epidemiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Philipp Mergenthaler
- Department of Neurology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany,NeuroCure Clinical Research Center, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany,Center for Stroke Research Berlin, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Benjamin Hotter
- Department of Neurology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany,NeuroCure Clinical Research Center, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Sarah Hoffmann
- Department of Neurology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany,NeuroCure Clinical Research Center, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Sophie Lehnerer
- NeuroCure Clinical Research Center, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany,Berlin Institute of Health (BIH), Berlin, Germany
| | - Christian Meisel
- Department of Immunology, Institute of Medical Immunology, Charité—Universitätsmedizin Berlin, Berlin, Germany,Labor Berlin, Charité Vivantes GmbH, Berlin, Germany
| | - Andreas Meisel
- Department of Neurology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany,NeuroCure Clinical Research Center, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany,Center for Stroke Research Berlin, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany,Integrated Myasthenia Gravis Center, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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Schubert M, Pelz A, Trautmann G, Block K, Furlan S, Gutsmann M, Kohler S, Volpe P, Blottner D, Meisel A, Salanova M. Opposite Regulation of Homer Signal at the NMJ Postsynaptic Micro Domain between Slow- and Fast-Twitch Muscles in an Experimentally Induced Autoimmune Myasthenia Gravis (EAMG) Mouse Model. Int J Mol Sci 2022; 23:ijms232315052. [PMID: 36499379 PMCID: PMC9738765 DOI: 10.3390/ijms232315052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/17/2022] [Accepted: 11/26/2022] [Indexed: 12/03/2022] Open
Abstract
Accelerated postsynaptic remodelling and disturbance of neuromuscular transmission are common features of autoimmune neurodegenerative diseases. Homer protein isoform expression, crosslinking activity and neuromuscular subcellular localisation are studied in mouse hind limb muscles of an experimentally induced autoimmune model of Myasthenia Gravis (EAMG) and correlated to motor end plate integrity. Soleus (SOL), extensor digitorum longus (EDL) and gastrocnemius (GAS) skeletal muscles are investigated. nAChR membrane clusters were studied to monitor neuromuscular junction (NMJ) integrity. Fibre-type cross-sectional area (CSA) analysis is carried out in order to determine the extent of muscle atrophy. Our findings clearly showed that crosslinking activity of Homer long forms (Homer 1b/c and Homer2a/b) are decreased in slow-twitch and increased in fast-twitch muscle of EAMG whereas the short form of Homer that disrupts Homer crosslinking (Homer1a) is upregulated in slow-twitch muscle only. Densitometry analysis showed a 125% increase in Homer protein expression in EDL, and a 45% decrease in SOL of EAMG mice. In contrast, nAChR fluorescence pixel intensity decreased in endplates of EAMG mice, more distinct in type-I dominant SOL muscle. Morphometric CSA of EAMG vs. control (CTR) revealed a significant reduction in EDL but not in GAS and SOL. Taken together, these results indicate that postsynaptic Homer signalling is impaired in slow-twitch SOL muscle from EAMG mice and provide compelling evidence suggesting a functional coupling between Homer and nAChR, underscoring the key role of Homer in skeletal muscle neurophysiology.
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Affiliation(s)
- Martin Schubert
- Institute of Integrative Neuroanatomy, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, 10115 Berlin, Germany
| | - Andreas Pelz
- Department of Experimental Neurology, Charité—Universitätsmedizin Berlin, 10115 Berlin, Germany
| | - Gabor Trautmann
- Institute of Integrative Neuroanatomy, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, 10115 Berlin, Germany
| | - Katharina Block
- Center of Space Medicine Berlin, Neuromuscular Signaling and System, 10115 Berlin, Germany
| | - Sandra Furlan
- C.N.R. Institute of Neuroscience, 35131 Padova, Italy
| | - Martina Gutsmann
- Institute of Integrative Neuroanatomy, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, 10115 Berlin, Germany
| | - Siegfried Kohler
- Department of Experimental Neurology, Charité—Universitätsmedizin Berlin, 10115 Berlin, Germany
| | - Pompeo Volpe
- Department of Biomedical Sciences, University of Padova, 35122 Padova, Italy
| | - Dieter Blottner
- Institute of Integrative Neuroanatomy, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, 10115 Berlin, Germany
- Center of Space Medicine Berlin, Neuromuscular Signaling and System, 10115 Berlin, Germany
| | - Andreas Meisel
- Department of Experimental Neurology, Charité—Universitätsmedizin Berlin, 10115 Berlin, Germany
| | - Michele Salanova
- Institute of Integrative Neuroanatomy, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, 10115 Berlin, Germany
- Center of Space Medicine Berlin, Neuromuscular Signaling and System, 10115 Berlin, Germany
- Correspondence: ; Tel.: +49-30-450528-354
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8
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Davis LA, Fogarty MJ, Brown A, Sieck GC. Structure and Function of the Mammalian Neuromuscular Junction. Compr Physiol 2022; 12:3731-3766. [PMID: 35950651 PMCID: PMC10461538 DOI: 10.1002/cphy.c210022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The mammalian neuromuscular junction (NMJ) comprises a presynaptic terminal, a postsynaptic receptor region on the muscle fiber (endplate), and the perisynaptic (terminal) Schwann cell. As with any synapse, the purpose of the NMJ is to transmit signals from the nervous system to muscle fibers. This neural control of muscle fibers is organized as motor units, which display distinct structural and functional phenotypes including differences in pre- and postsynaptic elements of NMJs. Motor units vary considerably in the frequency of their activation (both motor neuron discharge rate and duration/duty cycle), force generation, and susceptibility to fatigue. For earlier and more frequently recruited motor units, the structure and function of the activated NMJs must have high fidelity to ensure consistent activation and continued contractile response to sustain vital motor behaviors (e.g., breathing and postural balance). Similarly, for higher force less frequent behaviors (e.g., coughing and jumping), the structure and function of recruited NMJs must ensure short-term reliable activation but not activation sustained for a prolonged period in which fatigue may occur. The NMJ is highly plastic, changing structurally and functionally throughout the life span from embryonic development to old age. The NMJ also changes under pathological conditions including acute and chronic disease. Such neuroplasticity often varies across motor unit types. © 2022 American Physiological Society. Compr Physiol 12:1-36, 2022.
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Affiliation(s)
- Leah A. Davis
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Matthew J. Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Alyssa Brown
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Gary C. Sieck
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
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Lueangaram S, Tritanon O, Siriyotha S, Vanikieti K, Padungkiatsagul T, Preechawat P, Poonyathalang A, Dejthevaporn C, Pulkes T, Tunlayadechanont S, Jindahra P. Radiological Characteristics of Extraocular Muscles in Myasthenia Gravis Patients with Ocular Manifestations: A Case-Control Study. Clin Ophthalmol 2021; 15:2279-2285. [PMID: 34103891 PMCID: PMC8180303 DOI: 10.2147/opth.s280508] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/21/2021] [Indexed: 01/03/2023] Open
Abstract
Purpose To analyze radiological characteristics of the extraocular muscles (EOMs) in myasthenia gravis (MG) patients with ocular manifestations. Patients and Methods This retrospective case–control study included all MG cases with ocular manifestations, who attended a neuro-ophthalmology clinic at a university hospital, Bangkok, from April 2009 to June 2018. They experienced double vision and ophthalmoplegia. Control participants had normal eye movements. Orbital scans were thoroughly reviewed. We measured muscle thickness (MT) of the superior rectus, inferior rectus, medial rectus and lateral rectus muscles in both eyes using magnetic resonance imaging or computed tomography scan. The sum of the muscle thickness at all sites was calculated (MTsum). Comparisons of the mean MT of each muscle type and the mean MTsum between the MG and control groups were performed by using Student’s t-test. MRI signal intensities of the EOMs were also recorded. Results Twenty MG cases and 20 controls were included in the study. The mean MTsum was 23.7 (standard deviation 4.8) mm in the MG group and 32.6 (3.5) mm in the controls. There were statistically significant differences between the two groups with respect to the mean MT and mean MTsum (p <0.001). In the MG group, there was a negative correlation between the MTsum and disease duration (p= 0.03). By using coronal T2-weighted orbital MRI with fat suppression (T2W/FS), the most frequent finding was isointensity with central hypointensity of the EOMs in the MG group. Conclusion Atrophic EOMs were frequently found in the MG group, particularly in chronic cases. Isointensity with central hypointensity of EOMs on T2W/FS was also common in the MG group. These findings highlight the importance of muscle involvement in MG and may be helpful for clinical decision-making.
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Affiliation(s)
- Sirin Lueangaram
- Department of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Oranan Tritanon
- Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Sukanya Siriyotha
- Department of Clinical Epidemiology and Biostatistics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Kavin Vanikieti
- Department of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Tanyatuth Padungkiatsagul
- Department of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Pisit Preechawat
- Department of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Anuchit Poonyathalang
- Department of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Charungthai Dejthevaporn
- Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand
| | - Teeratorn Pulkes
- Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand
| | - Supoch Tunlayadechanont
- Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand
| | - Panitha Jindahra
- Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand
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10
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Ke L, Li Q, Song J, Jiao W, Ji A, Chen T, Pan H, Song Y. The mitochondrial biogenesis signaling pathway is a potential therapeutic target for myasthenia gravis via energy metabolism (Review). Exp Ther Med 2021; 22:702. [PMID: 34007311 PMCID: PMC8120506 DOI: 10.3892/etm.2021.10134] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/21/2020] [Indexed: 02/06/2023] Open
Abstract
Myasthenia gravis (MG) is an autoantibody-mediated autoimmune disease that is characterized by muscle weakness and fatigue. Traditional treatments for MG target the neuromuscular junction (NMJ) or the immune system. However, the efficacy of such treatments is limited, and novel therapeutic options for MG are urgently required. In the current review, a new therapeutic strategy is proposed based on the mitochondrial biogenesis and energy metabolism pathway, as stimulating mitochondrial biogenesis and the energy metabolism might alleviate myasthenia gravis. A number of cellular sensors of the energy metabolism were investigated, including AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1). AMPK and SIRT1 are sensors that regulate cellular energy homeostasis and maintain energy metabolism by balancing anabolism and catabolism. Peroxisome proliferator-activated receptor γ coactivator 1α and its downstream transcription factors nuclear respiratory factors 1, nuclear respiratory factors 2, and transcription factor A are key sensors of mitochondrial biogenesis, which can restore mitochondrial DNA and produce new mitochondria. These processes help to control muscle contraction and relieve the symptoms of MG, including muscle weakness caused by dysfunctional NMJ transmission. Therefore, the present review provides evidence for the therapeutic potential of targeting mitochondrial biogenesis for the treatment of MG.
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Affiliation(s)
- Lingling Ke
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China.,Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China
| | - Qing Li
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China.,Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China
| | - Jingwei Song
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China.,Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China
| | - Wei Jiao
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China.,Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China
| | - Aidong Ji
- Clinical Medical College of Acupuncture, Moxibustion and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Tongkai Chen
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China.,Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China
| | - Huafeng Pan
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China
| | - Yafang Song
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China.,Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China
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11
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Congenital Ophthalmoplegia and Late-Onset Limb Weakness Caused by MUSK Mutations. J Clin Neuromuscul Dis 2021; 21:222-224. [PMID: 32453097 DOI: 10.1097/cnd.0000000000000277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Congenital myasthenic syndromes are clinically and genetically heterogeneous disorders characterized by a neuromuscular transmission defect. Mutations in novel genes have been described in recent years. Among these, MUSK gene mutations are extremely rare, with only 8 families identified worldwide to date. We report a Spanish case, a carrier of one known hetero-allelic missense mutation and one newly identified MUSK gene variant. Our patient presented with congenital onset ophthalmoplegia and palpebral ptosis associated with limb-girdle weakness and exercise intolerance without prominent fatigability, developed during his twenties. He was misdiagnosed as mitochondrial myopathy because of paraclinic and histologic findings, but detailed clinical examination prompted us to reassess him with repetitive stimulation technique, demonstrating decremental response and suggesting myasthenic syndrome. A genetic study confirmed the clinical diagnosis allowing us to started treatment with excellent clinical response.
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12
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Jiao W, Hu F, Li J, Song J, Liang J, Li L, Song Y, Chen Z, Li Q, Ke L. Qiangji Jianli Decoction promotes mitochondrial biogenesis in skeletal muscle of myasthenia gravis rats via AMPK/PGC-1α signaling pathway. Biomed Pharmacother 2020; 129:110482. [PMID: 32768964 DOI: 10.1016/j.biopha.2020.110482] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 05/29/2020] [Accepted: 06/30/2020] [Indexed: 11/30/2022] Open
Abstract
The Qiangji Jianli Decoction (QJJLD) is an effective Chinese medicine formula for treating Myasthenia gravis (MG) in the clinic. QJJLD has been proven to regulate mitochondrial fusion and fission of skeletal muscle in myasthenia gravis. In this study, we investigated whether QJJLD plays a therapeutic role in regulating mitochondrial biogenesis in MG and explored the underlying mechanism. Rats were experimentally induced to establish autoimmune myasthenia gravis (EAMG) by subcutaneous immunization with R97-116 peptides. The treatment groups were administered three different dosages of QJJLD respectively. After the intervention of QJJLD, the pathological changes of gastrocnemius muscle in MG rats were significantly improved; SOD, GSH-Px, Na+-K+ ATPase and Ca2+-Mg2+ ATPase activities were increased; and MDA content was decreased in the gastrocnemius muscle. Moreover, AMPK, p38MAPK, PGC-1α, NRF-1, Tfam and COX IV mRNA and protein expression levels were also reversed by QJJLD. These results implied that QJJLD may provide a potential therapeutic strategy through promoting mitochondrial biogenesis to alleviate MG via activating the AMPK/PGC-1α signaling pathway.
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Affiliation(s)
- Wei Jiao
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China; Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China
| | - Fangyu Hu
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China; Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China
| | - Jinqiu Li
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China; Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China
| | - Jingwei Song
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China; Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China
| | - Jian Liang
- Guangdong Provincial Key Laboratory of New Drug Development and Research of Chinese Medicine, Mathematical Engineering Academy of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China
| | - Lanqi Li
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China; Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China
| | - Yafang Song
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China; Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China.
| | - Zhiwei Chen
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China; Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China
| | - Qing Li
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China; Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China
| | - Lingling Ke
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China; Institute of Pi-Wei, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, China
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13
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Abstract
Thirty to fifty percent of patients with acetylcholine receptor (AChR) antibody (Ab)-negative myasthenia gravis (MG) have Abs to muscle specific kinase (MuSK) and are referred to as having MuSK-MG. MuSK is a 100 kD single-pass post-synaptic transmembrane receptor tyrosine kinase crucial to the development and maintenance of the neuromuscular junction. The Abs in MuSK-MG are predominantly of the IgG4 immunoglobulin subclass. MuSK-MG differs from AChR-MG, in exhibiting more focal muscle involvement, including neck, shoulder, facial and bulbar-innervated muscles, as well as wasting of the involved muscles. MuSK-MG is highly associated with the HLA DR14-DQ5 haplotype and occurs predominantly in females with onset in the fourth decade of life. Some of the standard treatments of AChR-MG have been found to have limited effectiveness in MuSK-MG, including thymectomy and cholinesterase inhibitors. Therefore, current treatment involves immunosuppression, primarily by corticosteroids. In addition, patients respond especially well to B cell depletion agents, e.g., rituximab, with long-term remissions. Future treatments will likely derive from the ongoing analysis of the pathogenic mechanisms underlying this disease, including histologic and physiologic studies of the neuromuscular junction in patients as well as information derived from the development and study of animal models of the disease.
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Affiliation(s)
| | - David P. Richman
- Department of Neurology, University of California, Davis, Davis, CA, United States
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14
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Rivner MH, Pasnoor M, Dimachkie MM, Barohn RJ, Mei L. Muscle-Specific Tyrosine Kinase and Myasthenia Gravis Owing to Other Antibodies. Neurol Clin 2019; 36:293-310. [PMID: 29655451 DOI: 10.1016/j.ncl.2018.01.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Around 20% of patients with myasthenia gravis are acetylcholine receptor antibody negative; muscle-specific tyrosine kinase antibodies (MuSK) were identified as the cause of myasthenia gravis in 30% to 40% of these cases. Anti MuSK myasthenia gravis is associated with specific clinical phenotypes. One is a bulbar form with fewer ocular symptoms. Others show an isolated head drop or symptoms indistinguishable from acetylcholine receptor-positive myasthenia gravis. These patients usually respond well to immunosuppressive therapy, but not as well to cholinesterase inhibitors. Other antibodies associated with myasthenia gravis, including low-density lipoprotein receptor-related protein 4, are discussed.
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Affiliation(s)
- Michael H Rivner
- EMG Lab, Augusta University, 1120 15th Street, BP-4390, Augusta, GA 30912, USA.
| | - Mamatha Pasnoor
- Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Mazen M Dimachkie
- Department of Neurology, University of Kansas Medical Center, 3599 Rainbow Boulevard, Mail Stop 2012, Kansas City, KS 66103, USA
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mail Stop 4017, Kansas City, KS 66160, USA
| | - Lin Mei
- Department of Neuroscience and Regenerative Medicine, Augusta University, 1120 15th Street, CA-2014, Augusta, GA 30912, USA
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15
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Europa TA, Nel M, Heckmann JM. A review of the histopathological findings in myasthenia gravis: Clues to the pathogenesis of treatment-resistance in extraocular muscles. Neuromuscul Disord 2019; 29:381-387. [PMID: 31029532 DOI: 10.1016/j.nmd.2019.03.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/18/2019] [Accepted: 03/20/2019] [Indexed: 12/28/2022]
Abstract
In myasthenia gravis autoantibodies target components of the neuromuscular junction causing variable degrees of weakness. In most cases, autoantibodies trigger complement-mediated endplate damage and extraocular muscles may be most susceptible. A proportion of MG cases develop treatment-resistant ophthalmoplegia. We reviewed publications spanning 65 years reporting the histopathological findings in the muscles and extraocular muscles of myasthenic patients to determine whether pathological changes in extraocular muscles differ from non-ocular muscles. As extraocular muscles represent a unique muscle allotype we also compared their histopathology in myasthenia to those in strabismus. We found that in myasthenia gravis, the non-ocular muscles frequently demonstrate neurogenic changes regardless of myasthenic serotype. Mitochondrial stress/damage was also frequent in myasthenic muscles and possibly more evident in muscle-specific kinase antibody-positive MG. Although myasthenia-associated paralysed extraocular muscles demonstrated prominent fibro-fatty replacement and mitochondrial alterations, these features appeared commonly in paralysed extraocular muscles of any cause. We postulate that extraocular muscles may be more susceptible than limb muscles to poor contractility as a consequence of myasthenia, resulting in a cascade of atrophy signaling pathways and altered mitochondrial homeostasis which contribute to the tipping point in developing treatment-resistant myasthenic ophthalmoplegia. Early strategies to improve force generation in extraocular muscles are critical.
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Affiliation(s)
- Tarin A Europa
- Neurology Research Group, Division of Neurology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Melissa Nel
- Neurology Research Group, Division of Neurology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Jeannine M Heckmann
- Neurology Research Group, Division of Neurology, Department of Medicine, University of Cape Town, Cape Town, South Africa; Neurology Division, Department of Medicine, University of Cape Town, Cape Town, South Africa.
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16
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Evoli A, Alboini PE, Damato V, Iorio R, Provenzano C, Bartoccioni E, Marino M. Myasthenia gravis with antibodies to MuSK: an update. Ann N Y Acad Sci 2017; 1412:82-89. [PMID: 29266255 DOI: 10.1111/nyas.13518] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/06/2017] [Accepted: 09/12/2017] [Indexed: 02/06/2023]
Abstract
Myasthenia gravis with antibodies to the muscle-specific tyrosine kinase (MuSK+ MG) is a rare disease with distinctive pathogenic mechanisms and clinical features. An acute onset and predominant bulbar muscle weakness are very common and highly suggestive of the disease. On the other hand, a more indolent course, atypical ocular presentation, and signs of cholinergic hyperactivity may complicate the diagnosis. Though MuSK+ MG is still a severe disease, over the years we have observed a steady reduction in the rate of respiratory crisis and a significant improvement in the clinical outcome, both likely related to earlier diagnosis and timely treatment. Despite the improved management, MuSK+ MG patients tend to remain dependent on long-term immunosuppressive treatment and may develop permanent disabling weakness. In uncontrolled studies, B cell depletion with rituximab proved effective in most patients with refractory disease, inducing prolonged clinical responses associated with a sustained reduction of serum antibody levels. Promising results from experimental studies and case reports suggest that both 3,4-diaminopyridine and albuterol may be effective as symptomatic agents.
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Affiliation(s)
- Amelia Evoli
- Institute of Neurology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Paolo E Alboini
- Institute of Neurology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Valentina Damato
- Institute of Neurology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Raffaele Iorio
- Institute of Neurology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Carlo Provenzano
- Institute of General Pathology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Emanuela Bartoccioni
- Institute of General Pathology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Mariapaola Marino
- Institute of General Pathology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
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17
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Extraocular Muscle Findings in Myasthenia Gravis Associated Treatment-Resistant Ophthalmoplegia. J Neuroophthalmol 2017; 37:414-417. [PMID: 28742638 DOI: 10.1097/wno.0000000000000534] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We report the histopathological and ultrastructural tissue analysis of extraocular muscle (EOM) obtained from a patient with seronegative myasthenia gravis (MG) with treatment-resistant ophthalmoplegia for 3.5 years. The EOM demonstrated predominantly myopathic features and ultrastructural evidence of mitochondrial dysfunction, but the most striking features were increased endomysial collagen and adipocyte replacement of muscle fibers. By contrast, control EOM from a patient undergoing strabismus surgery for a sensory exotropia in a nonseeing eye and a similar duration of deviation, showed normal muscle histology. Although the histopathological and ultrastructural findings largely resemble those of limb muscle in MG, the abundant endomysial collagen may be nonspecific and secondary to poor force generation as a result of chronic ophthalmoplegia.
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18
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Muscle satellite cells are functionally impaired in myasthenia gravis: consequences on muscle regeneration. Acta Neuropathol 2017; 134:869-888. [PMID: 28756524 DOI: 10.1007/s00401-017-1754-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 06/30/2017] [Accepted: 07/21/2017] [Indexed: 12/14/2022]
Abstract
Myasthenia gravis (MG) is a neuromuscular disease caused in most cases by anti-acetyl-choline receptor (AChR) autoantibodies that impair neuromuscular signal transmission and affect skeletal muscle homeostasis. Myogenesis is carried out by muscle stem cells called satellite cells (SCs). However, myogenesis in MG had never been explored. The aim of this study was to characterise the functional properties of myasthenic SCs as well as their abilities in muscle regeneration. SCs were isolated from muscle biopsies of MG patients and age-matched controls. We first showed that the number of Pax7+ SCs was increased in muscle sections from MG and its experimental autoimmune myasthenia gravis (EAMG) mouse model. Myoblasts isolated from MG muscles proliferate and differentiate more actively than myoblasts from control muscles. MyoD and MyoG were expressed at a higher level in MG myoblasts as well as in MG muscle biopsies compared to controls. We found that treatment of control myoblasts with MG sera or monoclonal anti-AChR antibodies increased the differentiation and MyoG mRNA expression compared to control sera. To investigate the functional ability of SCs from MG muscle to regenerate, we induced muscle regeneration using acute cardiotoxin injury in the EAMG mouse model. We observed a delay in maturation evidenced by a decrease in fibre size and MyoG mRNA expression as well as an increase in fibre number and embryonic myosin heavy-chain mRNA expression. These findings demonstrate for the first time the altered function of SCs from MG compared to control muscles. These alterations could be due to the anti-AChR antibodies via the modulation of myogenic markers resulting in muscle regeneration impairment. In conclusion, the autoimmune attack in MG appears to have unsuspected pathogenic effects on SCs and muscle regeneration, with potential consequences on myogenic signalling pathways, and subsequently on clinical outcome, especially in the case of muscle stress.
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19
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Lin YP, Iqbal U, Nguyen PA, Islam MM, Atique S, Jian WS, Li YCJ, Huang CL, Hsu CH. The Concomitant Association of Thyroid Disorders and Myasthenia Gravis. Transl Neurosci 2017; 8:27-30. [PMID: 28729915 PMCID: PMC5443889 DOI: 10.1515/tnsci-2017-0006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/31/2017] [Indexed: 11/23/2022] Open
Abstract
Background Some of the thyroid disorders (TD) and Myasthenia gravis (MG) are autoimmune related disease. The purpose of the study to evaluate the relationship of MG with all morphological and functional thyroid disorders. Methods We constructed a population-based cohort study during the period from January 2000-December 2002 by using reimbursement data from the Bureau National Health Insurance (NHI) system in Taiwan. Patients with TD and MG were identified by referring to the ICD-9-CM codes. (ICD-10-CM as reference) .The association of TD with MG occurred only in the same person within the study period. The Q value was used to measure the strength of disease-disease associations. Results We obtained 520628 TD and 7965 MG records for analysis. Diffuse toxic goiter had highest association rate, followed by nontoxic nodular goiter, simple goiter, chronic lymphocytic thyroiditis, thyroid cancer, and toxic nodular goiter. Female and older patients had a higher rate than their male and younger counterparts, respectively. Functional abnormalities revealed higher incidence of thyrotoxicosis and hypothyroidism in both sexes. We also found the strongest association in men with chronic thyroiditis, diffuse toxic goiter, thyrotoxicosis, acquired hypothyroidism, thyroid cancer, and simple goiter. While an intermediate association was observed in female with diffuse toxic goiter, in a male with toxic and nontoxic nodular/multinodular goiters, in female with thyrotoxicosis, thyroid cancer and acquired hypothyroidism. Conclusion This population based cohort study showed potential association of all types of TD with MG, and observed a higher association rate in female autoimmune TD whereas males showed a higher strength of association.
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Affiliation(s)
- Yu-Pei Lin
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Usman Iqbal
- Masters Program in Global Health & Development Dept., College of Public Health, Taipei Medical University, Taipei, Taiwan.,International Center for Health Information Technology, Taipei, Taiwan
| | - Phung-Anh Nguyen
- International Center for Health Information Technology, Taipei, Taiwan.,Graduate Institute of Biomedical Informatics, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Md Mohaimenul Islam
- Graduate Institute of Biomedical Informatics, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Suleman Atique
- Graduate Institute of Biomedical Informatics, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Wen-Shan Jian
- International Center for Health Information Technology, Taipei, Taiwan.,School of Health Care Administration, Taipei Medical University, Taipei, Taiwan.,Faculty of Health Sciences, Macau University of Science and Technology, Macau, China
| | - Yu-Chuan Jack Li
- International Center for Health Information Technology, Taipei, Taiwan.,Graduate Institute of Biomedical Informatics, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,Chair, Department of Dermatology, Wan Fang Hospital, Taipei, Taiwan
| | - Chen-Ling Huang
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Chung-Huei Hsu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan.,Department of Nuclear Medicine, Taipei Medical University Hospital, Taipei, Taiwan
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20
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Kirzinger L, Khomenko A, Schulte-Mattler W, Backhaus R, Platen S, Schalke B. Myopathy in Childhood Muscle-Specific Kinase Myasthenia Gravis. Pediatr Neurol 2016; 65:90-92. [PMID: 27697312 DOI: 10.1016/j.pediatrneurol.2016.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 08/01/2016] [Accepted: 08/06/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND Adult and pediatric patients suffering from MuSK (muscle-specific kinase) -antibody positive myasthenia gravis exhibit similar features to individuals with acetylcholine receptor (AChR) antibodies, but they differ in several characteristics such as a predominant bulbar, respiratory and neck weakness, a generally worse disease severity and a tendency to develop muscle atrophy. Muscle atrophy is a rare phenomenon that is usually restricted to the facial muscles. RESULTS We describe a girl with MuSK-antibody positive myasthenia gravis who developed a myopathy with severe generalized muscular weakness, muscle atrophy, and myopathic changes on electromyography. CONCLUSION This is the first published example of a generalized myopathic syndrome in myasthenia gravis. We review the relevant literature and discuss the hypothesis of a mitochondrial myopathy as a pathogenic mechanism in MuSK-antibody positive myasthenia gravis.
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Affiliation(s)
- Lukas Kirzinger
- Department of Neurology, University of Regensburg, Regensburg, Germany.
| | - Andrei Khomenko
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | | | - Roland Backhaus
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | - Sabine Platen
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | - Berthold Schalke
- Department of Neurology, University of Regensburg, Regensburg, Germany
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21
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Sudulagunta SR, Sepehrar M, Sodalagunta MB, Settikere Nataraju A, Bangalore Raja SK, Sathyanarayana D, Gummadi S, Burra HK. Refractory myasthenia gravis - clinical profile, comorbidities and response to rituximab. GERMAN MEDICAL SCIENCE : GMS E-JOURNAL 2016; 14:Doc12. [PMID: 27790079 PMCID: PMC5067337 DOI: 10.3205/000239] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 09/13/2016] [Indexed: 01/01/2023]
Abstract
Introduction: Myasthenia gravis (MG) is an antibody mediated autoimmune neuromuscular disorder characterized by fatigable muscle weakness. A proportion of myasthenia gravis patients are classified as refractory due to non responsiveness to conventional treatment. This retrospective study was done to evaluate clinical profile, epidemiological, laboratory, and features of patients with MG and mode of management using rituximab and complications. Methods: Data of myasthenia gravis patients admitted or presented to outpatient department (previous medical records) with MG between January 2008 and January 2016 were included. A total of 512 patients fulfilled the clinical and diagnostic criteria of myasthenia gravis of which 76 patients met the diagnostic certainty for refractory myasthenia gravis and were evaluated. Results: Out of 76 refractory MG patients, 53 (69.73%) patients fulfilled all the three defined criteria. The median age of onset of the refractory MG group was 36 years with a range of 27-53 years. In our study 25 patients (32.89%) belonged to the age group of 21-30 years. Anti-MuSK antibodies were positive in 8 non-refractory MG patients (2.06%) and 36 refractory MG patients (47.36%). Mean HbA1C was found to be 8.6±2.33. The dose of administered prednisone decreased by a mean of 59.7% (p=3.3x10-8) to 94.6% (p=2.2x10-14) after the third cycle of rituximab treatment. Conclusion: The refractory MG patients are most commonly female with an early age of onset, anti-MuSK antibodies, and thymomas. Refractory MG patients have higher prevalence and poor control (HbA1C >8%) of diabetes mellitus and dyslipidemia probably due to increased steroid usage. Rituximab is very efficient in treatment of refractory MG with adverse effects being low.
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Affiliation(s)
| | | | | | | | | | | | - Siddharth Gummadi
- Columbia Asia Hospital, Kirloskar Business Park, Hebbal, Bangalore, India
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22
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23
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The Myotonic Plot Thickens: Electrical Myotonia in Antimuscle-Specific Kinase Myasthenia Gravis. Case Rep Neurol Med 2016; 2015:242691. [PMID: 26770848 PMCID: PMC4681818 DOI: 10.1155/2015/242691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 11/22/2015] [Indexed: 11/18/2022] Open
Abstract
Electrical myotonia is known to occur in a number of inherited and acquired disorders including myotonic dystrophies, channelopathies, and metabolic, toxic, and inflammatory myopathies. Yet, electrical myotonia in myasthenia gravis associated with antibodies against muscle-specific tyrosine kinase (MuSK) has not been previously reported. We describe two such patients, both of whom had a typical presentation of proximal muscle weakness with respiratory failure in the context of a significant electrodecrement in repetitive nerve stimulation. In both cases, concentric needle examination revealed electrical myotonia combined with myopathic motor unit morphology and early recruitment. These findings suggest that MuSK myasthenia should be included within the differential diagnosis of disorders with electrical myotonia.
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Abstract
Rhabdomyolysis is characterized by severe acute muscle injury resulting in muscle pain, weakness, and/or swelling with release of myofiber contents into the bloodstream. Symptoms develop over hours to days after an inciting factor and may be associated with dark pigmentation of the urine. Serum creatine kinase and urine myoglobin levels are markedly elevated. Clinical examination, history, laboratory studies, muscle biopsy, and genetic testing are useful tools for diagnosis of rhabdomyolysis, and they can help differentiate acquired from inherited causes of rhabdomyolysis. Acquired causes include substance abuse, medication or toxic exposures, electrolyte abnormalities, endocrine disturbances, and autoimmune myopathies. Inherited predisposition to rhabdomyolysis can occur with disorders of glycogen metabolism, fatty acid β-oxidation, and mitochondrial oxidative phosphorylation. Less common inherited causes of rhabdomyolysis include structural myopathies, channelopathies, and sickle-cell disease. This review focuses on the differentiation of acquired and inherited causes of rhabdomyolysis and proposes a practical diagnostic algorithm. Muscle Nerve 51: 793-810, 2015.
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Affiliation(s)
- Jessica R Nance
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Andrew L Mammen
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Muscle Disease Unit, Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Building 50, Room 1146, Bethesda, Maryland, 20892, USA
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IL-6 and Akt are involved in muscular pathogenesis in myasthenia gravis. Acta Neuropathol Commun 2015; 3:1. [PMID: 25627031 PMCID: PMC4308930 DOI: 10.1186/s40478-014-0179-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 12/15/2014] [Indexed: 01/11/2023] Open
Abstract
Introduction Anti-acetylcholine receptor (AChR) autoantibodies target muscles in spontaneous human myasthenia gravis (MG) and its induced experimental autoimmune model MG (EAMG). The aim of this study was to identify novel functional mechanisms occurring in the muscle pathology of myasthenia. Results A transcriptome analysis performed on muscle tissue from MG patients (compared with healthy controls) and from EAMG rats (compared with control rats) revealed a deregulation of genes associated with the Interleukin-6 (IL-6) and Insulin-Like Growth Factor 1 (IGF-1) pathways in both humans and rats. The expression of IL-6 and its receptor IL-6R transcripts was found to be altered in muscles of EAMG rats and mice compared with control animals. In muscle biopsies from MG patients, IL-6 protein level was higher than in control muscles. Using cultures of human muscle cells, we evaluated the effects of anti-AChR antibodies on IL-6 production and on the phosphorylation of Protein Kinase B (PKB/Akt). Most MG sera and some monoclonal anti-AChR antibodies induced a significant increase in IL-6 production by human muscle cells. Furthermore, Akt phosphorylation in response to insulin was decreased in the presence of monoclonal anti-AChR antibodies. Conclusions Anti-AChR antibodies alter IL-6 production by muscle cells, suggesting a putative novel functional mechanism of action for the anti-AChR antibodies. IL-6 is a myokine with known effects on signaling pathways such as Akt/mTOR (mammalian Target of Rapamycin). Since Akt plays a key role in multiple cellular processes, the reduced phosphorylation of Akt by the anti-AChR antibodies may have a significant impact on the muscle fatigability observed in MG patients. Electronic supplementary material The online version of this article (doi:10.1186/s40478-014-0179-6) contains supplementary material, which is available to authorized users.
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Furuta N, Ishizawa K, Shibata M, Tsukagoshi S, Nagamine S, Makioka K, Fujita Y, Ikeda M, Yoshimura S, Motomura M, Okamoto K, Ikeda Y. Anti-MuSK Antibody-positive Myasthenia Gravis Mimicking Amyotrophic Lateral Sclerosis. Intern Med 2015; 54:2497-501. [PMID: 26424311 DOI: 10.2169/internalmedicine.54.4645] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We herein investigated the clinical features of three patients with anti-muscle-specific tyrosine kinase (MuSK) antibody-positive myasthenia gravis (MG), which was initially difficult to distinguish from amyotrophic lateral sclerosis (ALS). The patients exhibited dropped head syndrome or dysphagia as initial symptoms. Although their clinical findings were compatible with the revised El Escorial Criteria for ALS, their progression appeared to be more rapid than that of ALS. Both the edrophonium and repetitive nerve stimulation tests yielded negative results, and diurnal fluctuation was not confirmed. The patients were ultimately diagnosed with anti-MuSK antibody-positive MG. We therefore recommend the measurement of anti-MuSK antibodies when encountering such cases.
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Affiliation(s)
- Natsumi Furuta
- Department of Neurology, Gunma University Graduate School of Medicine, Japan
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Phillips WD, Christadoss P, Losen M, Punga AR, Shigemoto K, Verschuuren J, Vincent A. Guidelines for pre-clinical animal and cellular models of MuSK-myasthenia gravis. Exp Neurol 2014; 270:29-40. [PMID: 25542979 DOI: 10.1016/j.expneurol.2014.12.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/12/2014] [Accepted: 12/17/2014] [Indexed: 11/17/2022]
Abstract
Muscle-specific tyrosine kinase (MuSK) autoantibodies are the hallmark of a form of myasthenia gravis (MG) that can challenge the neurologist and the experimentalist. The clinical disease can be difficult to treat effectively. MuSK autoantibodies affect the neuromuscular junction in several ways. When added to muscle cells in culture, MuSK antibodies disperse acetylcholine receptor clusters. Experimental animals actively immunized with MuSK develop MuSK autoantibodies and muscle weakness. Weakness is associated with reduced postsynaptic acetylcholine receptor numbers, reduced amplitudes of miniature endplate potentials and endplate potentials, and failure of neuromuscular transmission. Similar impairments have been found in mice injected with IgG from MG patients positive for MuSK autoantibody (MuSK-MG). The active and passive models have begun to reveal the mechanisms by which MuSK antibodies disrupt synaptic function at the neuromuscular junction, and should be valuable in developing therapies for MuSK-MG. However, translation into new and improved treatments for patients requires procedures that are not too cumbersome but suitable for examining different aspects of MuSK function and the effects of potential therapies. Study design, conduct and analysis should be carefully considered and transparently reported. Here we review what has been learnt from animal and culture models of MuSK-MG, and offer guidelines for experimental design and conduct of studies, including sample size determination, randomization, outcome parameters and precautions for objective data analysis. These principles may also be relevant to the increasing number of other antibody-mediated diseases that are now recognized.
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Affiliation(s)
- W D Phillips
- School of Medical Sciences (Physiology) and Bosch Institute, Anderson Stuart Bldg (F13), University of Sydney, NSW 2006, Australia.
| | - P Christadoss
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - M Losen
- Department of Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - A R Punga
- Institute of Neuroscience, Department of Clinical Neurophysiology, Uppsala University, Uppsala, Sweden.
| | - K Shigemoto
- Department of Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
| | - J Verschuuren
- Department of Neurology, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands.
| | - A Vincent
- Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom.
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Gomez AM, Vanheel A, Losen M, Molenaar PC, De Baets MH, Noben JP, Hellings N, Martinez-Martinez P. Proteomic analysis of rat tibialis anterior muscles at different stages of experimental autoimmune myasthenia gravis. J Neuroimmunol 2013; 261:141-5. [PMID: 23791150 DOI: 10.1016/j.jneuroim.2013.05.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 05/10/2013] [Indexed: 12/28/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disease in which autoantibodies, most commonly directed against the acetylcholine receptor (AChR), impair neuromuscular transmission and cause muscle weakness. In this study, we utilized two-dimensional difference in-gel electrophoresis (2D-DIGE) to analyze the muscle's proteomic profile at different stages of experimental autoimmune myasthenia gravis (EAMG). We identified twenty-two differentially expressed proteins, mainly related to metabolic and stress-response pathways. Interestingly, these identified proteins have also been associated with other contraction-impairing muscle pathologies (e.g. inclusion body myositis), suggesting a similar response of the muscle to such conditions.
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Affiliation(s)
- Alejandro M Gomez
- Division Neuroscience, School for Mental Health and Neuroscience, Maastricht University, 6200 MD Maastricht, the Netherlands
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Rossato M, Zabeo E, Burei M, Cecchin D, Guzzardo V, Fassina A, Vettor R. Lung Cancer and Paraneoplastic Neurologic Syndromes. Case Report and Review of the Literature. Clin Lung Cancer 2013; 14:301-9. [DOI: 10.1016/j.cllc.2012.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 11/14/2012] [Accepted: 11/20/2012] [Indexed: 12/11/2022]
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Richman DP, Nishi K, Ferns MJ, Schnier J, Pytel P, Maselli RA, Agius MA. Animal models of antimuscle-specific kinase myasthenia. Ann N Y Acad Sci 2013; 1274:140-7. [PMID: 23252909 DOI: 10.1111/j.1749-6632.2012.06782.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Antimuscle-specific kinase (anti-MuSK) myasthenia (AMM) differs from antiacetylcholine receptor myasthenia gravis in exhibiting more focal muscle involvement (neck, shoulder, facial, and bulbar muscles) with wasting of the involved, primarily axial, muscles. AMM is not associated with thymic hyperplasia and responds poorly to anticholinesterase treatment. Animal models of AMM have been induced in rabbits, mice, and rats by immunization with purified xenogeneic MuSK ectodomain, and by passive transfer of large quantities of purified serum IgG from AMM patients into mice. The models have confirmed the pathogenic role of the MuSK antibodies in AMM and have demonstrated the involvement of both the presynaptic and postsynaptic components of the neuromuscular junction. The observations in this human disease and its animal models demonstrate the role of MuSK not only in the formation of this synapse but also in its maintenance.
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Affiliation(s)
- David P Richman
- Department of Neurology, Center for Neuroscience, University of California, Davis, 95616, USA.
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Angelini C, Martignago S, Bisciglia M. New treatments for myasthenia: a focus on antisense oligonucleotides. DRUG DESIGN DEVELOPMENT AND THERAPY 2013; 7:13-7. [PMID: 23341732 PMCID: PMC3546757 DOI: 10.2147/dddt.s25716] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Autoimmune myasthenia gravis (MG) is a neuromuscular disorder caused by autoantibodies directed against the acetylcholine receptor (AChR). Current symptomatic therapy is based on acetylcholinesterase (AChE) drugs. The available long-term current therapy includes steroids and other immunomodulatory agents. MG is associated with the production of a soluble, rare isoform of AChE, also referred as the “read-through” transcript (AChE-R). Monarsen (EN101) is a synthetic antisense compound directed against the AChE gene. Monarsen was administered in 16 patients with MG and 14 patients achieved a clinically significant response. The drug is now in a Phase II study. Further investigations are required to confirm its long-term effects.
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Kostrominova TY, Reiner DS, Haas RH, Ingermanson R, McDonough PM. Automated methods for the analysis of skeletal muscle fiber size and metabolic type. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:275-332. [PMID: 24016528 DOI: 10.1016/b978-0-12-407694-5.00007-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
It is of interest to quantify the size, shape, and metabolic subtype of skeletal muscle fibers in many areas of biomedical research. To do so, skeletal muscle samples are sectioned transversely to the length of the muscle and labeled for extracellular or membrane proteins to delineate the fiber boundaries and additionally for biomarkers related to function or metabolism. The samples are digitally photographed and the fibers "outlined" for quantification of fiber cross-sectional area (CSA) using pointing devices interfaced to a computer, which is tedious, prone to error, and can be nonobjective. Here, we review methods for characterizing skeletal muscle fibers and describe new automated techniques, which rapidly quantify CSA and biomarkers. We discuss the applications of these methods to the characterization of mitochondrial dysfunctions, which underlie a variety of human afflictions, and we present a novel approach, utilizing images from the online Human Protein Atlas to predict relationships between fiber-specific protein expression, function, and metabolism.
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Abstract
Myasthenia gravis (MG) is the most common primary disorder of neuromuscular transmission. MG can be treated as a chronic disease with medication, surgery, plasmapheresis, and I.V. immunoglobulin.
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Meinen S, Lin S, Rüegg MA, Punga AR. Fatigue and muscle atrophy in a mouse model of myasthenia gravis is paralleled by loss of sarcolemmal nNOS. PLoS One 2012; 7:e44148. [PMID: 22952904 PMCID: PMC3429452 DOI: 10.1371/journal.pone.0044148] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 07/30/2012] [Indexed: 02/01/2023] Open
Abstract
Myasthenia Gravis (MG) patients suffer from chronic fatigue of skeletal muscles, even after initiation of proper immunosuppressive medication. Since the localization of neuronal nitric oxide synthase (nNOS) at the muscle membrane is important for sustained muscle contraction, we here study the localization of nNOS in muscles from mice with acetylcholine receptor antibody seropositive (AChR+) experimental autoimmune MG (EAMG). EAMG was induced in 8 week-old male mice by immunization with AChRs purified from torpedo californica. Sham-injected wild type mice and mdx mice, a model for Duchenne muscular dystrophy, were used for comparison. At EAMG disease grade 3 (severe myasthenic weakness), the triceps, sternomastoid and masseter muscles were collected for analysis. Unlike in mdx muscles, total nNOS expression as well as the presence of its binding partner syntrophin α-1, were not altered in EAMG. Immunohistological and biochemical analysis showed that nNOS was lost from the muscle membrane and accumulated in the cytosol, which is likely the consequence of blocked neuromuscular transmission. Atrophy of all examined EAMG muscles were supported by up-regulated transcript levels of the atrogenes atrogin-1 and MuRF1, as well as MuRF1 protein, in combination with reduced muscle fiber diameters. We propose that loss of sarcolemmal nNOS provides an additional mechanism for the chronic muscle fatigue and secondary muscle atrophy in EAMG and MG.
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MESH Headings
- Animals
- Autoantibodies/immunology
- Cytosol/enzymology
- Disease Models, Animal
- Immunization
- Male
- Mice
- Mice, Inbred C57BL
- Models, Biological
- Muscle Denervation
- Muscle Fatigue
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/immunology
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Muscular Atrophy/complications
- Muscular Atrophy/immunology
- Muscular Atrophy/pathology
- Muscular Atrophy/physiopathology
- Myasthenia Gravis, Autoimmune, Experimental/complications
- Myasthenia Gravis, Autoimmune, Experimental/immunology
- Myasthenia Gravis, Autoimmune, Experimental/pathology
- Myasthenia Gravis, Autoimmune, Experimental/physiopathology
- Nitric Oxide Synthase Type I/deficiency
- Nitric Oxide Synthase Type I/genetics
- Nitric Oxide Synthase Type I/metabolism
- Phenotype
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cholinergic/metabolism
- Sarcolemma/enzymology
- Sarcolemma/pathology
- Weight Loss
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Affiliation(s)
- Sarina Meinen
- Department of Neurobiology/Pharmacology, Biozentrum, University of Basel, Basel, Switzerland
| | - Shuo Lin
- Department of Neurobiology/Pharmacology, Biozentrum, University of Basel, Basel, Switzerland
| | - Markus A. Rüegg
- Department of Neurobiology/Pharmacology, Biozentrum, University of Basel, Basel, Switzerland
| | - Anna Rostedt Punga
- Department of Neurobiology/Pharmacology, Biozentrum, University of Basel, Basel, Switzerland
- * E-mail:
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Muscle specific kinase autoantibodies cause synaptic failure through progressive wastage of postsynaptic acetylcholine receptors. Exp Neurol 2012; 237:286-95. [PMID: 22789393 DOI: 10.1016/j.expneurol.2012.06.034] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 06/27/2012] [Accepted: 06/28/2012] [Indexed: 11/21/2022]
Abstract
In myasthenia gravis muscle weakness is caused by autoantibodies against components of the neuromuscular junction. Patient autoantibodies against muscle specific kinase (MuSK) deplete MuSK from the postsynaptic membrane and reproduce signs of myasthenia gravis when injected into mice. Here we have examined the time-course of structural and functional changes that lead up to synaptic failure. C57Bl6J mice received daily injections of anti-MuSK patient IgG for 15 days. Mice began to lose weight from day 12 and demonstrated whole-body weakness by day 14. Electromyography indicated synaptic impairment from day 6 in the gastrocnemius muscle and from day 10 in the diaphragm muscle. Confocal microscopy revealed linear declines in the area and density of postsynaptic acetylcholine receptors (3-5% per day) from day 1 through day 15 of the injection series in all five muscles examined. Intracellular recordings from the diaphragm muscle revealed comparable progressive declines in the amplitude of the endplate potential and miniature endplate potential of 3-4% per day. Neither quantal content nor the postsynaptic action potential threshold changed significantly over the injection series. The inverse relationship between the quantal amplitude of a synapse and its quantal content disappeared only late in the injection series (day 10). Our results suggest that the primary myasthenogenic action of anti-MuSK IgG is to cause wastage of postsynaptic acetylcholine receptor density. Consequent reductions in endplate potential amplitudes culminated in failure of neuromuscular transmission.
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Abstracts of the 2012 Meeting of the International Neuro-Ophthalmology Society, Singapore. Neuroophthalmology 2012. [DOI: 10.3109/01658107.2012.690640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Lavrnic D, Dakovic M, Peric S, Rakocevic-Stojanovic V, Basta I, Marjanovic I, Stosic-Opincal T, Lavrnic S. Proton magnetic resonance spectroscopy of the intrinsic tongue muscles in patients with myasthenia gravis with different autoantibodies. J Neurol Sci 2011; 302:25-8. [PMID: 21236447 DOI: 10.1016/j.jns.2010.12.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 12/10/2010] [Accepted: 12/13/2010] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To assess lipid composition of the intrinsic tongue muscles in patients with myasthenia gravis (MG). METHODS This study included 15 MG patients with antibodies against muscle-specific kinase (MuSK), 15 matched MG patients with antibodies against acetylcholine receptor (AChR) and 15 matched healthy subjects. Middle posterior region of the tongue was analyzed by single voxel point-resolved proton magnetic resonance spectroscopy (MRS) using 1.5T MRI scanner. RESULTS MRS obtained from subject with AChR MG showed a broad resonance arising from methylene groups of lipids (PMN) with no observable shoulder attributed to methyl groups (PML). Full-width at half maximum (FWHM) of PMN+PML peak showed higher value in patients with AChR MG in comparison to healthy subjects and MuSK MG patients (p<0.05). In patients with MuSK MG, the shape and FWHM of PMN+PML peak was similar as in healthy subjects (p>0.05), with tendency toward increased ratio between PMN and resonance from vinyl protons of lipids (PV). In both AChR and MuSK MG, total creatine resonance (creatine+phosphocreatine, CP) was almost absent with significant increase of PMN/CP ratio in comparison to healthy subjects (p<0.05). CONCLUSION MRS is useful in revealing muscle lipid composition in MG. In patients with AChR MG, MRS showed increased lipid content in the tongue muscles due to the lipid migration from intra- to extramyocellular space. Finding in patients with MuSK MG might reflect intramyocellular lipid deposition in the tongue. CP decrease in tongue muscles indicated impairment of oxidative metabolism in both AChR MG and MuSK MG.
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Affiliation(s)
- Dragana Lavrnic
- Institute of Neurology, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia.
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Comparison of muscle ultrastructure in myasthenia gravis with anti-MuSK and anti-AChR antibodies. J Neurol 2010; 258:746-52. [DOI: 10.1007/s00415-010-5823-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 10/22/2010] [Accepted: 10/29/2010] [Indexed: 10/18/2022]
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Oh SJ. Muscle-specific receptor tyrosine kinase antibody positive myasthenia gravis current status. J Clin Neurol 2009; 5:53-64. [PMID: 19587811 PMCID: PMC2706412 DOI: 10.3988/jcn.2009.5.2.53] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 05/22/2009] [Accepted: 05/22/2009] [Indexed: 12/04/2022] Open
Abstract
Muscle-specific tyrosine-kinase-antibody-positive myasthenia gravis (MuSK-MG) has emerged as a distinct entity since 2001. This disease has been reported worldwide, but with varying rates among patients with generalized acetylcholine-receptor-antibody-negative MG. MuSK-MG was detected in approximately 37% of generalized acetylcholine receptor antibody-negative MG. MuSK-MG patients were predominantly female with more prominent facial and bulbar involvement and more frequent crises. Disease onset tended to be earlier. Patients tended to have a relatively poor edrophonium response but showed prominent decrement in the repetitive nerve stimulation test in the facial muscles. Patients were more likely to display poor tolerance of, or a lack of improvement with, anticholinesterase agents. Somewhat better response was observed with steroids and plasma exchange. Most were managed successfully with aggressive immunomodulatory therapies, although a higher proportion of MuSK-MG patients had a refractory course when compared with other forms of generalized MG. I present here an up-to-date overview on MuSK-MG based on our experience at the University of Alabama at Birmingham and the existing literature.
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Affiliation(s)
- Shin Joong Oh
- Distinguished Professor of Neurology, The University of Alabama at Birmingham, The Veterans Affairs Medical Center, Birmingham, Alabama, USA
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