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Zhang J, Huang J, Lan J, Li Q, Ke L, Jiang Q, Li Y, Zhang H, Zhong H, Yang P, Chen T, Song Y. Astragaloside IV protects against autoimmune myasthenia gravis in rats via regulation of mitophagy and apoptosis. Mol Med Rep 2024; 30:129. [PMID: 38785143 PMCID: PMC11140232 DOI: 10.3892/mmr.2024.13253] [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: 12/19/2023] [Accepted: 04/12/2024] [Indexed: 05/25/2024] Open
Abstract
Astragaloside IV (AS‑IV) has various pharmacological effects, including antioxidant and immunoregulatory properties, which can improve myasthenia gravis (MG) symptoms. However, the potential mechanism underlying the effects of AS‑IV on MG remains to be elucidated. The present study aimed to investigate whether AS‑IV has a therapeutic effect on MG and its potential mechanism of action. By subcutaneously immunizing rats with R97‑116 peptide, an experimental autoimmune (EA) MG rat model was established. AS‑IV (40 or 80 mg/kg/day) treatment was then applied for 28 days after modeling. The results demonstrated that AS‑IV significantly ameliorated the weight loss, Lennon score and pathological changes in the gastrocnemius muscle of EAMG rats compared with the model group. Additionally, the levels of acetylcholine receptor antibody (AChR‑Ab) were significantly decreased, whereas mitochondrial function [ATPase and cytochrome c (Cyt‑C) oxidase activities] and ultrastructure were improved in the AS‑IV treated rats. Moreover, the mRNA and protein expression levels of phosphatase and tensin homolog‑induced putative kinase 1, Parkin, LC3II and Bcl‑2, key signaling molecules for mitophagy and apoptosis, were upregulated, whereas the mRNA and protein expression levels of p62, Cyt‑C, Bax, caspase 3 and caspase 9 were downregulated following AS‑IV intervention. In conclusion, AS‑IV may protect against EAMG in a rat model by modulating mitophagy and apoptosis. These findings indicated the potential mechanism underlying the effects of AS‑IV on MG and provided novel insights into treatment strategies for MG.
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Affiliation(s)
- Jingjing Zhang
- 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
| | - Jiayan Huang
- 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
| | - Jinlian Lan
- 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
| | - 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
| | - Qilong Jiang
- Department of Gastrosplenic Diseases, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China
| | - Yanwu 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
| | - Han Zhang
- School of Chinese Materia Medica, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, P.R. China
| | - Huiya Zhong
- 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
| | - Peidan Yang
- 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
| | - Tongkai Chen
- 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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Kawaguchi N, Tsuda K, Tanaka N, Kerstens R, Harada D. Myasthenia Gravis Disease Burden and Its Impact on Satisfaction with Life: A Qualitative Survey of Patients' Perspectives in Japan. Neurol Ther 2024:10.1007/s40120-024-00617-6. [PMID: 38748320 DOI: 10.1007/s40120-024-00617-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/05/2024] [Indexed: 06/22/2024] Open
Abstract
INTRODUCTION Myasthenia gravis (MG) has a negative impact on patients' health-related quality of life; however, many clinicians do not fully understand their patients' lived experience of the disease. To understand the actual conditions of patients with MG and clarify the problems they perceive, we conducted a survey to evaluate the effects of the disease on patients' daily life and work. METHODS A questionnaire-based, qualitative, cross-sectional, non-interventional survey was conducted in Japan between April and May 2022 in patients with MG who were receiving regular outpatient treatment. The questionnaire included items regarding the patients' disease characteristics and experience, satisfaction with life, current treatment status, and treatment satisfaction. RESULTS In total, 452 patients were included in the survey population (66.6% aged ≥ 60 years; 64.6% with MG disease duration ≥ 10 years; 76.6% acetylcholine receptor [AChR] autoantibody positive). The symptoms of MG had a significant impact on the patients' daily lives, with the most common symptoms being fatigability (74.8%), ptosis (59.7%), diplopia (54.2%), and weakness in the arms and/or legs (50.9%). Patients commonly identified exercise (73.7%), work 68.0%), hobbies (60.4%), travel (60.0%), and socializing with friends (59.7%) as being difficult to perform, with approximately 50% of patients reporting that hospitalization sometimes interfered with their ability to work. In total, 27.2% of patients were dissatisfied with life, with the highest rates of dissatisfaction among patients who were either positive for muscle-specific kinase (MuSK) autoantibodies or seronegative for both AChR and MuSK autoantibodies. CONCLUSION In Japanese patients with MG, over 25% are dissatisfied with life, indicating several unmet needs in this population.
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Affiliation(s)
| | - Koichi Tsuda
- argenx Japan K.K., HULIC JP Akasaka Building, 2-5-8 Akasaka, Minato-ku, Tokyo, 107-0052, Japan.
| | - Nozomu Tanaka
- argenx Japan K.K., HULIC JP Akasaka Building, 2-5-8 Akasaka, Minato-ku, Tokyo, 107-0052, Japan
| | | | - Daisuke Harada
- argenx Japan K.K., HULIC JP Akasaka Building, 2-5-8 Akasaka, Minato-ku, Tokyo, 107-0052, Japan
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Luong K, Lozier BK, Novis CL, Smith TL, Zuromski LM, Peterson LK. Comparison of three methods for the detection of antibodies against muscle-specific kinase. J Immunol Methods 2024; 526:113627. [PMID: 38311009 DOI: 10.1016/j.jim.2024.113627] [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: 11/01/2023] [Revised: 02/01/2024] [Accepted: 02/01/2024] [Indexed: 02/06/2024]
Abstract
OBJECTIVES To compare 3 different methods for the detection of antibodies against muscle-specific kinase (MuSK). METHODS MuSK antibody testing was performed in 237 serum samples by enzyme-linked immunosorbent assay (ELISA) and fixed cell-based assay (f-CBA-IFA). One hundred and forty-eight (148) of the sera had previously been tested by RIA during clinical testing: 47 MuSK antibody positive and 101 MuSK antibody negative. Of the MuSK RIA negative antibodies, 46 tested positive for other neural antibodies. Additionally, 89 sera were subsequently tested by all three methods: 70 healthy controls and 19 sera positive for other neural antibodies. RESULTS Qualitative inter-assay agreement based on tiered RIA values was 100% for results of 1.00 nmol/L or greater by both methods; 81% and 94% for results between 0.21 and 0.99 nmol/L by ELISA and f-CBA-IFA, respectively; and 0% for results of 0.04-0.20 nmol/L by both methods. Negative results showed 100% agreement between RIA and both ELISA and f-CBA-IFA (n = 55). None of the controls positive for other neural autoantibodies or healthy controls were positive in any assay. CONCLUSION Overall, excellent agreement was observed between the 3 methods used to detect antibodies against MuSK. Both the f-CBA-IFA and ELISA performed comparably to RIA and exhibited excellent overall accuracy for MuSK IgG detection, with the f-CBA-IFA demonstrating higher agreement between positive samples with the RIA than the ELISA without identifying false positives in the control samples. Advantages of non-radioactive methods for the detection of MuSK antibodies include reduced handling and disposal of hazardous materials, potential for automation and the reagents having a longer shelf-life, reducing costs associated with both workflow and lot validations. Thus, commercially available ELISA and transfected cell-based assays are viable alternatives to the traditional radioactive assay used for serologic determination of MuSK IgG.
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Affiliation(s)
- Kyphuong Luong
- ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108, USA
| | - Bucky K Lozier
- ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108, USA
| | - Camille L Novis
- ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108, USA
| | - Tammy L Smith
- ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108, USA; Department of Pathology, University of Utah School of Medicine, 15 N Medical Dr. East Ste. 1100, Salt Lake City, UT 84112, USA; Geriatric Research Education and Clinical Center, George E. Whalen Department of Veterans Affairs Medical Center, Salt Lake City, UT 84148, USA; Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; Neurology Service, George E. Whalen Department of Veterans Affairs Medical Center, Salt Lake City, UT 84148, USA
| | - Lauren M Zuromski
- ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108, USA
| | - Lisa K Peterson
- ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108, USA; Department of Pathology, University of Utah School of Medicine, 15 N Medical Dr. East Ste. 1100, Salt Lake City, UT 84112, USA.
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Liao X, Wang Y, Lai X, Wang S. The role of Rapsyn in neuromuscular junction and congenital myasthenic syndrome. BIOMOLECULES & BIOMEDICINE 2023; 23:772-784. [PMID: 36815443 PMCID: PMC10494853 DOI: 10.17305/bb.2022.8641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/02/2023] [Accepted: 02/17/2023] [Indexed: 02/23/2023]
Abstract
Rapsyn, an intracellular scaffolding protein associated with the postsynaptic membranes in the neuromuscular junction (NMJ), is critical for nicotinic acetylcholine receptor clustering and maintenance. Therefore, Rapsyn is essential to the NMJ formation and maintenance, and Rapsyn mutant is one of the reasons causing the pathogenies of congenital myasthenic syndrome (CMS). In addition, there is little research on Rapsyn in the central nervous system (CNS). In this review, the role of Rapsyn in the NMJ formation and the mutation of Rapsyn leading to CMS will be reviewed separately and sequentially. Finally, the potential function of Rapsyn is prospected.
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Affiliation(s)
- Xufeng Liao
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Yingxing Wang
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Xinsheng Lai
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
| | - Shunqi Wang
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
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Severe Obstructive Sleep Apnea in an Adolescent with Hypernasality, Dysarthria, and Muscle Weakness. Ann Am Thorac Soc 2022; 19:1764-1768. [PMID: 36178398 DOI: 10.1513/annalsats.202201-030cc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Huang Q, Li F, Zhao S. Spotlight on MuSK positive myasthenia gravis: clinical characteristics, treatment and outcomes. BMC Neurol 2022; 22:73. [PMID: 35246057 PMCID: PMC8895578 DOI: 10.1186/s12883-022-02593-6] [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: 08/28/2021] [Accepted: 02/16/2022] [Indexed: 11/10/2022] Open
Abstract
Background To investigate the clinical characteristics, treatments and outcomes of patients with myasthenia gravis with antibodies to muscle-specific tyrosine kinase (MuSK-MG). Methods We retrospectively reviewed the cases of 21 patients with confirmed MuSK-MG between January 2012 and January 2020 in our centre. Detailed clinical data and long-term follow-up information were summarized. Results Females (17/21, 81%) predominated among these MuSK-MG patients, and the mean age of onset in this group was 51.86 ± 16.16 years. MuSK-MG patients were divided into three subgroups according to the symptoms of muscle weakness at onset: ocular myasthenia gravis (OMG, 47.6%), bulbar myasthenia gravis (BMG, 42.9%), and generalized myasthenia gravis (GMG, 9.5%). The mean progression time from symptom onset to other muscle group involvement in OMG patients was 4.38 ± 2.54 months. Pyridostigmine bromide was adopted in 81.0% of patients, and 90.5% of patients received corticosteroids. Compared to usage in hospitals, the median daily dose of corticosteroids decreased significantly at the last follow-up. A total of 85.7% of patients received a long-term follow-up, with an average time of 1202.17 ± 976.73 days. At the end of the follow-up period, 4.8% of patients had achieved complete stable remission, 42.9% of patients had minimal manifestations, 19.0% had improved, the condition of 4.8% of patients remained unchanged, and 9.5% of patients died. Conclusion Female patients were more prevalent in this study, and MuSK-MG patients rapidly progressed to a generalized state. Although approximately 50% of MuSK-MG patients can achieve a favourable outcome with conventional immunosuppressants, complete stable remission is rare, and approximately 15% respond poorly. More effective medications should be explored in these patients. Supplementary Information The online version contains supplementary material available at 10.1186/s12883-022-02593-6.
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Affiliation(s)
- Qi Huang
- Department of Thoracic Surgery, The First Affiliated Hospital of Zhengzhou University, 1 Jianshe East Road, Zhengzhou, 450003, Henan, China
| | - Feng Li
- Department of Thoracic Surgery, The First Affiliated Hospital of Zhengzhou University, 1 Jianshe East Road, Zhengzhou, 450003, Henan, China
| | - Song Zhao
- Department of Thoracic Surgery, The First Affiliated Hospital of Zhengzhou University, 1 Jianshe East Road, Zhengzhou, 450003, Henan, China.
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Punga AR, Maddison P, Heckmann JM, Guptill JT, Evoli A. Epidemiology, diagnostics, and biomarkers of autoimmune neuromuscular junction disorders. Lancet Neurol 2022; 21:176-188. [DOI: 10.1016/s1474-4422(21)00297-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/18/2021] [Accepted: 08/25/2021] [Indexed: 12/14/2022]
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Jiao L, Li H, Guo S. Eculizumab treatment for myasthenia gravis subgroups: 2021 update. J Neuroimmunol 2022; 362:577767. [PMID: 34823117 DOI: 10.1016/j.jneuroim.2021.577767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 11/01/2021] [Accepted: 11/13/2021] [Indexed: 01/21/2023]
Abstract
Eculizumab is a recombinant humanized monoclonal antibody that targets the complement protein C5, inhibiting its cleavage into C5a and C5b and ultimately preventing the formation of C5b-9 membrane attack complex (MACs), thereby protecting the neuromuscular junction from the damage of complement activation. In 2017, eculizumab became the second FDA-approved medication for AchR-positive generalized myasthenia gravis (gMG) patients based on the successful results of a randomized, double-blinded, placebo-controlled, phase 2, phase 3 study (the REGAIN trial) and its open-label extension study. Despite the efficacy of eculizumab in treating AchR antibody-positive refractory gMG was demonstrated in the REGAIN study, there is few information on its efficacy in other subgroup of MG patients including seronegative MG, thymoma-associated MG and MG crisis. This narrative review summarizes current clinical studies of eculizumab in these refractory gMG patients, with a focus on the therapeutic efficacy and tolerability in different subgroup of MG.
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Affiliation(s)
- Li Jiao
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China
| | - Honghao Li
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China
| | - Shougang Guo
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China.
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Comparative Analysis of BIOCHIP Mosaic-Based Indirect Immunofluorescence with Enzyme-Linked Immunosorbent Assay for Diagnosing Myasthenia Gravis. Diagnostics (Basel) 2021; 11:diagnostics11112098. [PMID: 34829445 PMCID: PMC8619605 DOI: 10.3390/diagnostics11112098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/04/2021] [Accepted: 11/10/2021] [Indexed: 11/17/2022] Open
Abstract
Background: The detection of anti-acetylcholine receptor (AChR) and anti-muscle-specific tyrosine kinase (MuSK) antibodies is useful in myasthenia gravis (MG) diagnosis and management. BIOCHIP mosaic-based indirect immunofluorescence is a novel analytical method, which employs the simultaneous detection of anti-AChR and anti-MuSK antibodies in a single miniature incubation field. In this study, we compare, for the first time, the BIOCHIP MG mosaic with conventional enzyme-linked immunosorbent assay (ELISA) in the diagnosis of MG. Methods: A total of 71 patients with MG diagnosis were included in the study. Anti-AChR and anti-MuSK antibodies were measured separately by two different ELISA and simultaneously by BIOCHIP. The results were then compared. Results: The overall concordance between ELISA and BIOCHIP for anti-AChR reactivity was 74%. Cohen’s kappa was 0.51 (95% CI 0.32–0.71), which corresponds to 90% of the maximum possible kappa (0.57), given the observed marginal frequencies. The overall concordance for anti-MuSK reactivity was 84%. Cohen’s kappa was 0.11 (95% CI 0.00–0.36), which corresponds to 41% of the maximum possible kappa (0.27). Conclusion: The overall concordance among assays is not optimal.
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Jacob S, Mazibrada G, Irani SR, Jacob A, Yudina A. The Role of Plasma Exchange in the Treatment of Refractory Autoimmune Neurological Diseases: a Narrative Review. J Neuroimmune Pharmacol 2021; 16:806-817. [PMID: 34599742 PMCID: PMC8714620 DOI: 10.1007/s11481-021-10004-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 07/22/2021] [Indexed: 11/30/2022]
Abstract
Autoimmune neurological disorders are commonly treated with immunosuppressive therapy. In patients with refractory conditions, standard immunosuppression is often insufficient for complete recovery or to prevent relapses. These patients rely on other treatments to manage their disease. While treatment of refractory cases differs between diseases, intravenous immunoglobulin, plasma exchange (PLEX), and immune-modulating treatments are commonly used. In this review, we focus on five autoimmune neurological disorders that were the themes of the 2018 Midlands Neurological Society meeting on PLEX in refractory neurology: Autoimmune Encephalitis (AE), Multiple Sclerosis (MS), Neuromyelitis Optica Spectrum disorders (NMOSD), Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) and Myasthenia Gravis (MG). The diagnosis of inflammatory neuropathies is often challenging, and while PLEX can be very effective in refractory autoimmune diseases, its ineffectiveness can be confounded by misdiagnosis. One example is POEMS syndrome (characterized by Polyneuropathy Organomegaly, Endocrinopathy, Myeloma protein, Skin changes), which is often wrongly diagnosed as CIDP; and while CIDP responds well to PLEX, POEMS does not. Accurate diagnosis is therefore essential. Success rates can also differ within 'one' disease: e.g. response rates to PLEX are considerably higher in refractory relapsing remitting MS compared to primary or secondary progressive MS. When sufficient efforts are made to correctly pinpoint the diagnosis along with the type and subtype of refractory autoimmune disease, PLEX and other immunotherapies can play a valuable role in the patient management.
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Affiliation(s)
- Saiju Jacob
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom. .,Department of Neurology, Queen Elizabeth Hospital Birmingham, Birmingham, United Kingdom.
| | - Gordon Mazibrada
- Department of Neurology, Queen Elizabeth Hospital Birmingham, Birmingham, United Kingdom
| | - Sarosh R Irani
- Oxford Autoimmune Neurology Group, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Anu Jacob
- Department of Neurology, The Walton Centre NHS Foundation Trust, NMO Service, Liverpool, United Kingdom.,Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
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A Case of MuSK Myasthenia Gravis Presenting With Persistent Respiratory Insufficiency. J Clin Neuromuscul Dis 2021; 23:39-42. [PMID: 34431800 DOI: 10.1097/cnd.0000000000000374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ABSTRACT Muscle-specific kinase (MuSK) antibody is seen in 4%-10% of patients with myasthenia gravis (MG), with 40% of these patients reporting bulbar weakness as the initial symptom. We present the case of a 40-year-old woman with MuSK MG whose only presenting symptom was progressive respiratory insufficiency necessitating BiPAP use 16-24 hours daily. She was unresponsive to treatment for cardiac and pulmonary causes and thus referred to neurology. Initial workup directed toward autoimmune and genetic myopathies was unrevealing. MuSK antibodies were positive (60.7 nmol/L, nl 0.00-0.02). Electrodiagnostic studies were unremarkable other than single fiber electromyography which was consistent with a defect in neuromuscular transmission. Treatment with prednisone, plasma exchange, and rituximab led to improvement to reliance on BiPAP only at night. However, her most treatment refractory and quality of life limiting symptom continues to be respiratory insufficiency. Further investigation to better characterize differential response to treatment in this subset of patients with MuSK MG may be needed.
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Abstract
Neuromuscular respiratory failure can result from any disease that causes weakness of bulbar and/or respiratory muscles. Once compensatory mechanisms are overwhelmed, hypoxemic and hypercapnic respiratory failure ensues. The diagnosis of neuromuscular respiratory failure is primarily clinical, but arterial blood gases, bedside spirometry, and diaphragmatic ultrasonography can help in early assessment. Intensive care unit (ICU) admission is indicated for patients with severe bulbar weakness or rapidly progressing appendicular weakness. Intubation should be performed electively, particularly in patients with dysautonomia. Patients with an underlying treatable cause have the potential to regain functional independence with meticulous ICU care.
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13
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Disease severity and response to treatment in Iranian patients with myasthenia gravis. Neurol Sci 2021; 43:1233-1237. [PMID: 34143342 DOI: 10.1007/s10072-021-05382-0] [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: 01/17/2021] [Accepted: 06/04/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE Myasthenia gravis (MG) is a potentially fatal neuromuscular disorder if left untreated. In this study, we tried to address the possible demographic, clinical, and laboratory determinants of severity and outcome in Iranian MG patients over a follow-up period of more than 5 years. METHODS Demographic and diagnostic data (age, age of onset, antibody status, thymus pathology, and duration of the disease) of the patients with MG were extracted. Maximal disease severity and post-intervention status were assessed according to the recommendations of the task force of the Myasthenia Gravis Foundation of America. RESULTS In our series of 146 patients, MG was more severe in older, anti-muscle specific tyrosine kinase (MuSK) positive, and thymomatous patients. Seropositivity to the MuSK antibody and the presence of thymoma determined the need for immunosuppressive drugs. However, the number of patients requiring more than one immunosuppressive was not significantly different among various subtypes. CONCLUSIONS The overall outcome was favorable in the majority of patients, despite differences in the disease course and severity. In contrary to the previous reports, anti-MuSK positive patients in our series did not need a more vigorous treatment regimen comparing other serologic subtypes of MG.
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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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15
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Justo ME, Aldecoa M, Cela E, Leoni J, González Maglio DH, Villa AM, Aguirre F, Paz ML. Low Vitamin D Serum Levels in a Cohort of Myasthenia Gravis Patients in Argentina. Photochem Photobiol 2021; 97:1145-1149. [PMID: 33866582 DOI: 10.1111/php.13432] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/12/2021] [Indexed: 11/29/2022]
Abstract
There are limited and controversial studies that address the role of vitamin D (vitD), a vitamin with immunomodulatory effects, in myasthenia gravis (MG), a neuromuscular autoimmune disease. We aimed to assess 25-hydroxy vitamin D (25(OH)D) levels and to evaluate possible associations with the clinical severity and other biomarkers of the disease. Serum levels of 25(OH)D, anti-acetylcholine receptor antibodies and complement factor C5a were measured in MG patients (n = 66) and healthy volunteers (HV) (n = 25). Participants were evaluated through questionnaires to determine vitD intake and sunlight exposure. Severity scores were registered for MG patients. We found an 89.4% of MG individuals with nonsufficient levels of vitD, in comparison with 68.0% in the group of HV (OR = 3.96; P = 0.024). In addition, there was an inverse correlation between 25(OH)D levels and one of the scores (P = 0.037 r = -0.26, CI95 = -0.49 to -0.0087). However, when we compared 25(OH)D median serum levels between MG patients and HV, no statistically significant differences have been found. This is the first report of vitD status in a cohort of Argentinean MG patients, where we found that patients are more likely to have nonsufficient levels of vitD compared to healthy people and that patients with more severe disease have lower levels of vitD.
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Affiliation(s)
- Mariano E Justo
- Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética, Cátedra de Inmunología, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral "Prof. Dr. Ricardo A. Margni" (IDEHU), CONICET - Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mayra Aldecoa
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía, Centro Argentino de Neuroinmunología (CADENI), Facultad de Medicina - Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Eliana Cela
- Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética, Cátedra de Inmunología, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral "Prof. Dr. Ricardo A. Margni" (IDEHU), CONICET - Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Juliana Leoni
- Instituto de Estudios de la Inmunidad Humoral "Prof. Dr. Ricardo A. Margni" (IDEHU), CONICET - Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Daniel H González Maglio
- Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética, Cátedra de Inmunología, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral "Prof. Dr. Ricardo A. Margni" (IDEHU), CONICET - Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Andrés M Villa
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía, Centro Argentino de Neuroinmunología (CADENI), Facultad de Medicina - Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Florencia Aguirre
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía, Centro Argentino de Neuroinmunología (CADENI), Facultad de Medicina - Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mariela L Paz
- Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética, Cátedra de Inmunología, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral "Prof. Dr. Ricardo A. Margni" (IDEHU), CONICET - Universidad de Buenos Aires, Buenos Aires, Argentina
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16
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Giant cell myositis associated with concurrent myasthenia gravis: a case-based review of the literature. Clin Rheumatol 2021; 40:3841-3851. [PMID: 33629204 PMCID: PMC7904393 DOI: 10.1007/s10067-021-05619-5] [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: 10/19/2020] [Revised: 01/10/2021] [Accepted: 01/27/2021] [Indexed: 11/09/2022]
Abstract
The term “giant cell myositis” has been used to refer to muscle diseases characterized histologically by multinucleated giant cells. Myasthenia gravis is an autoimmune neuromuscular junction disorder. The rare concurrence of giant cell myositis with myasthenia gravis has been reported; however, the clinical and histological features have varied widely. Here, we present such a case and a review of the literature. An 82-year-old woman admitted for subacute, progressive, proximal muscle weakness developed acute-onset dysphagia, dysphonia, and respiratory distress 5 days after admission. Laboratory findings were positive for acetylcholine receptor binding antibodies and striational muscle antibodies against titin. Muscle biopsy demonstrated widespread muscle fiber necrosis with multinucleated giant cells, consistent with giant cell myositis. She died despite treatment with pulse methylprednisolone and plasma exchange. A literature review of the PubMed and Scopus databases from 1944 to 2020 identified 15 additional cases of these co-existing diagnoses. We found that giant cell myositis with myasthenia gravis primarily affects female patients, is typically diagnosed in the 6–7th decades, and is characterized by the presence of thymoma. Muscle histology predominantly shows giant cell infiltrate without granulomas. The onset of myasthenia gravis symptoms may precede, follow, or coincide with symptoms of myositis. Treatment with thymectomy, anticholinesterase inhibitors, or immunosuppressive therapy may lead to favorable clinical outcomes.
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17
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Paz ML, Barrantes FJ. Cholesterol in myasthenia gravis. Arch Biochem Biophys 2021; 701:108788. [PMID: 33548213 DOI: 10.1016/j.abb.2021.108788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 01/13/2021] [Accepted: 01/26/2021] [Indexed: 01/03/2023]
Abstract
The cholinergic neuromuscular junction is the paradigm peripheral synapse between a motor neuron nerve ending and a skeletal muscle fiber. In vertebrates, acetylcholine is released from the presynaptic site and binds to the nicotinic acetylcholine receptor at the postsynaptic membrane. A variety of pathologies among which myasthenia gravis stands out can impact on this rapid and efficient signaling mechanism, including autoimmune diseases affecting the nicotinic receptor or other synaptic proteins. Cholesterol is an essential component of biomembranes and is particularly rich at the postsynaptic membrane, where it interacts with and modulates many properties of the nicotinic receptor. The profound changes inflicted by myasthenia gravis on the postsynaptic membrane necessarily involve cholesterol. This review analyzes some aspects of myasthenia gravis pathophysiology and associated postsynaptic membrane dysfunction, including dysregulation of cholesterol metabolism in the myocyte brought about by antibody-receptor interactions. In addition, given the extensive therapeutic use of statins as the typical cholesterol-lowering drugs, we discuss their effects on skeletal muscle and the possible implications for MG patients under chronic treatment with this type of compound.
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Affiliation(s)
- Mariela L Paz
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética, Cátedra de Inmunología, Buenos Aires, Argentina; CONICET, Universidad de Buenos Aires, Instituto de Estudios de la Inmunidad Humoral "Prof. Dr. Ricardo A. Margni" (IDEHU), Buenos Aires, Argentina
| | - Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Biomedical Research Institute (BIOMED), UCA, CONICET, Av. Alicia Moreau de Justo 1600, C1107AFF, Buenos Aires, Argentina.
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Barrantes FJ. Possible implications of dysregulated nicotinic acetylcholine receptor diffusion and nanocluster formation in myasthenia gravis. Neural Regen Res 2021; 16:242-246. [PMID: 32859770 PMCID: PMC7896218 DOI: 10.4103/1673-5374.290880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Myasthenia gravis is a rare and invalidating disease affecting the neuromuscular junction of voluntary muscles. The classical form of this autoimmune disease is characterized by the presence of antibodies against the most abundant protein in the neuromuscular junction, the nicotinic acetylcholine receptor. Other variants of the disease involve autoimmune attack of non-receptor scaffolding proteins or enzymes essential for building or maintaining the integrity of this peripheral synapse. This review summarizes the participation of the above proteins in building the neuromuscular junction and the destruction of this cholinergic synapse by autoimmune aggression in myasthenia gravis. The review also covers the application of a powerful biophysical technique, superresolution optical microscopy, to image the nicotinic receptor in live cells and follow its motional dynamics. The hypothesis is entertained that anomalous nanocluster formation by antibody crosslinking may lead to accelerated endocytic internalization and elevated turnover of the receptor, as observed in myasthenia gravis.
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Evoli A, Iorio R. Controversies in Ocular Myasthenia Gravis. Front Neurol 2020; 11:605902. [PMID: 33329368 PMCID: PMC7734350 DOI: 10.3389/fneur.2020.605902] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 10/26/2020] [Indexed: 12/12/2022] Open
Abstract
Myasthenia gravis (MG) with symptoms limited to eye muscles [ocular MG (OMG)] is a rare disease. OMG incidence varies according to ethnicity and age of onset. In recent years, both an increase in incidence rate, particularly in the elderly, and a lower risk for secondary generalization may have contributed to the growing disease prevalence in Western countries. OMG should be considered in patients with painless ptosis and extrinsic ophthalmoparesis. Though asymmetric muscle involvement and symptom fluctuations are typical, in some cases, OMG can mimic isolated cranial nerve paresis, internuclear ophthalmoplegia, and conjugate gaze palsy. Diagnostic confirmation can be challenging in patients negative for anti-acetylcholine receptor and anti-muscle-specific tyrosine kinase antibodies on standard radioimmunoassay. Early treatment is aimed at relieving symptoms and at preventing disease progression to generalized MG. Despite the absence of high-level evidence, there is general agreement on the efficacy of steroids at low to moderate dosage; immunosuppressants are considered when steroid high maintenance doses are required. The role of thymectomy in non-thymoma patients is controversial. Prolonged exposure to immunosuppressive therapy has a negative impact on the health-related quality of life in a proportion of these patients. OMG is currently excluded from most of the treatments recently developed in generalized MG.
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Affiliation(s)
- Amelia Evoli
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.,Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Raffaele Iorio
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.,Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
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Takamori M. Myasthenia Gravis: From the Viewpoint of Pathogenicity Focusing on Acetylcholine Receptor Clustering, Trans-Synaptic Homeostasis and Synaptic Stability. Front Mol Neurosci 2020; 13:86. [PMID: 32547365 PMCID: PMC7272578 DOI: 10.3389/fnmol.2020.00086] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/28/2020] [Indexed: 12/18/2022] Open
Abstract
Myasthenia gravis (MG) is a disease of the postsynaptic neuromuscular junction (NMJ) where nicotinic acetylcholine (ACh) receptors (AChRs) are targeted by autoantibodies. Search for other pathogenic antigens has detected the antibodies against muscle-specific tyrosine kinase (MuSK) and low-density lipoprotein-related protein 4 (Lrp4), both causing pre- and post-synaptic impairments. Agrin is also suspected as a fourth pathogen. In a complex NMJ organization centering on MuSK: (1) the Wnt non-canonical pathway through the Wnt-Lrp4-MuSK cysteine-rich domain (CRD)-Dishevelled (Dvl, scaffold protein) signaling acts to form AChR prepatterning with axonal guidance; (2) the neural agrin-Lrp4-MuSK (Ig1/2 domains) signaling acts to form rapsyn-anchored AChR clusters at the innervated stage of muscle; (3) adaptor protein Dok-7 acts on MuSK activation for AChR clustering from “inside” and also on cytoskeleton to stabilize AChR clusters by the downstream effector Sorbs1/2; (4) the trans-synaptic retrograde signaling contributes to the presynaptic organization via: (i) Wnt-MuSK CRD-Dvl-β catenin-Slit 2 pathway; (ii) Lrp4; and (iii) laminins. The presynaptic Ca2+ homeostasis conditioning ACh release is modified by autoreceptors such as M1-type muscarinic AChR and A2A adenosine receptors. The post-synaptic structure is stabilized by: (i) laminin-network including the muscle-derived agrin; (ii) the extracellular matrix proteins (including collagen Q/perlecan and biglycan which link to MuSK Ig1 domain and CRD); and (iii) the dystrophin-associated glycoprotein complex. The study on MuSK ectodomains (Ig1/2 domains and CRD) recognized by antibodies suggested that the MuSK antibodies were pathologically heterogeneous due to their binding to multiple functional domains. Focussing one of the matrix proteins, biglycan which functions in the manner similar to collagen Q, our antibody assay showed the negative result in MG patients. However, the synaptic stability may be impaired by antibodies against MuSK ectodomains because of the linkage of biglycan with MuSK Ig1 domain and CRD. The pathogenic diversity of MG is discussed based on NMJ signaling molecules.
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Datta S, Singh S, Govindarajan R. Retrospective Analysis of Eculizumab in Patients with Acetylcholine Receptor Antibody-Negative Myasthenia Gravis: A Case Series. J Neuromuscul Dis 2020; 7:269-277. [PMID: 32444555 PMCID: PMC7369065 DOI: 10.3233/jnd-190464] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Background: The role of the complement cascade in acetylcholine receptor antibody-negative (AChR–) myasthenia gravis (MG) is unclear. Objective: To assess the efficacy and tolerability of eculizumab (terminal complement inhibitor) in patients with AChR–MG. Methods: Retrospective chart review of data from six patients treated for 12 months with eculizumab for treatment-refractory, AChR–(by radioimmunoassay) generalized MG (gMG). The eculizumab dose was 900 mg/week for 4 weeks then 1200 mg every 2 weeks. Outcome measures were Myasthenia Gravis–Activities of Daily Living (MG-ADL) scores, number of exacerbations, and qualitative physical assessments based on selected items of the Quantitative Myasthenia Gravis evaluation (ptosis, double vision, eye closure, duration of ability to stretch out limbs). Results: All patients were female (mean age, 50.8 years). In the 12 months before eculizumab initiation, all measures were relatively stable. After its initiation, clinically meaningful reductions (≥2 points) in total MG-ADL scores were observed before or at 5 months and were maintained to Month 12 in all patients; mean (standard deviation [SD]) scores were 11.3 (0.9) and 5.0 (0.9), respectively. There was also a reduction in the mean (SD) number of exacerbations per patient, from 2.8 (1.2) to 0.3 (0.5) in the 12 months before and after eculizumab initiation, respectively. Physical assessment ratings were improved in all patients. Adverse events were reported in four patients, but all were mild and none were treatment-related. Conclusions: This small retrospective analysis provides preliminary evidence for the efficacy of eculizumab in treatment-refractory gMG that was AChR–according to radioimmunoassay. Larger, more robust studies are warranted to evaluate this further.
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Affiliation(s)
- Sorabh Datta
- University of Missouri Health Care, Columbia, MO, USA
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22
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Paz ML, Barrantes FJ. Autoimmune Attack of the Neuromuscular Junction in Myasthenia Gravis: Nicotinic Acetylcholine Receptors and Other Targets. ACS Chem Neurosci 2019; 10:2186-2194. [PMID: 30916550 DOI: 10.1021/acschemneuro.9b00041] [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] Open
Abstract
The nicotinic acetylcholine receptor (nAChR) family, the archetype member of the pentameric ligand-gated ion channels, is ubiquitously distributed in the central and peripheral nervous systems, and its members are the targets for both genetic and acquired forms of neurological disorders. In the central nervous system, nAChRs contribute to the pathological mechanisms of neurodegenerative disorders, such as Alzheimer and Parkinson diseases. In the peripheral nerve-muscle synapse, the vertebrate neuromuscular junction, "classical" myasthenia gravis (MG) and other forms of neuromuscular transmission disorders are antibody-mediated autoimmune diseases. In MG, antibodies to the nAChR bind to the postsynaptic receptors and activate the classical complement pathway culminating in the formation of the membrane attack complex, with the subsequent destruction of the postsynaptic apparatus. Divalent nAChR-antibodies also cause internalization and loss of the nAChRs. Loss of receptors by either mechanism results in the muscle weakness and fatigability that typify the clinical manifestations of the disease. Other targets for antibodies, in a minority of patients, include muscle specific kinase (MuSK) and low-density lipoprotein related protein 4 (LRP4). This brief Review analyzes the current status of muscle-type nAChR in relation to the pathogenesis of autoimmune diseases affecting the peripheral cholinergic synapse.
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Affiliation(s)
- Mariela L. Paz
- Immunology Department, Faculty of Pharmacy and Biochemistry, IDEHU-CONICET, University of Buenos Aires, Junin 956, C1113AAD Buenos Aires, Argentina
| | - Francisco J. Barrantes
- Laboratory of Molecular Neurobiology, Biomedical Research Institute (BIOMED), UCA-CONICET, Av. Alicia Moreau de Justo 1600, C1107AFF Buenos Aires, Argentina
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23
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Nagappa M, Mahadevan A, Gangadhar Y, Patil SA, Bokolia S, Bindu PS, Sinha S, Taly AB. Autoantibodies in acquired myasthenia gravis: Clinical phenotype and immunological correlation. Acta Neurol Scand 2019; 139:428-437. [PMID: 30693486 DOI: 10.1111/ane.13071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 12/25/2018] [Accepted: 01/04/2019] [Indexed: 12/26/2022]
Abstract
BACKGROUND Data on antibody profile in myasthenia gravis (MG) from India are limited. OBJECTIVES To investigate antibody profile in patients with MG and their clinical correlates. PATIENTS AND METHODS Patients of MG (n = 85, M:F::1.1:1, mean age: 39.29 ± 17.3 years, mean symptom duration: 72.94 ± 91.8 months) were evaluated for clinical features, MG foundation of America (MGFA) score, response to treatment, and outcome at last follow-up. Antibodies to acetylcholine receptor (AChR), muscle-specific kinase (MUSK), titin and ryanodine receptor (RYR) were analysed using ELISA. RESULTS Based on the regional distribution of weakness, the cohort could be categorized as: generalized: 60, ocular: 16 and oculo-bulbar: 9. Sixty patients were followed up for a mean duration of 26.74 ± 13.8 months. Outcome at last follow-up was as follows: remission-22, no remission-33 and dead-5. AChR and MUSK antibodies were detected in 58 and 8 patients, respectively. Frequency of generalized MG, worse MGFA score during the disease course and thymomatous histology significantly correlated with presence of AChR-antibodies, though outcome at last follow-up was comparable between AChR-antibody positive and negative groups. Patients with MUSK antibodies had oculo-bulbar or generalized MG and frequent respiratory crisis, but majority improved or remitted with treatment. Titin antibodies were detected in 31.8% and RYR antibodies in 32.9%. Their presence did not correlate with age at onset of MG, severity or presence of thymoma. CONCLUSION This report highlights the spectrum of antibodies in MG in an Indian cohort. AChR-antibody positivity correlated with clinical severity. Outcome was good in majority of MUSK antibody-positive MG. The role of other antibodies, complementary vs epiphenomenon, remains open.
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Affiliation(s)
- Madhu Nagappa
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Anita Mahadevan
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Department of Neuropathology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Yashwanth Gangadhar
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Department of Neuropathology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Shripad A. Patil
- Department of Neuromicrobiology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Suresh Bokolia
- Department of Neuromicrobiology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Parayil S. Bindu
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Sanjib Sinha
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Arun B. Taly
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
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Naides SJ. The role of the laboratory in the expanding field of neuroimmunology: Autoantibodies to neural targets. J Immunol Methods 2018; 463:1-20. [PMID: 30300607 DOI: 10.1016/j.jim.2018.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/12/2018] [Indexed: 12/15/2022]
Abstract
Accelerated identification of autoantibodies associated with previously idiopathic neurological disease has provided insights into disease mechanisms, enhanced understanding of neurological function, and opportunities for improved therapeutic interventions. The role of the laboratory in the expanding field of neuroimmunology is critical as specific autoantibody identification provides guidance to clinicians in diagnosis, prognosis, tumor search strategies, and therapeutic interventions. The number of specific autoantibodies identified continues to increase and newer testing strategies increase efficiencies in the laboratory and availability to clinicians. The need for broadly targeted efficient testing is underscored by the variability in clinical presentation and tumor associations attributable to a specific autoantibody, and conversely the various autoantibody specificities that can be the cause of a given clinical presentation. While many of the antineural antibodies were first recognized in the setting of neoplastic disease, idiopathic autoimmune neurological disease in the absence of underlying tumor is increasingly recognized. Appropriation of therapeutic modalities used to treat autoimmune disease to treat these autoantibody mediated neurological diseases has improved patient outcomes. Interaction between clinicians and laboratorians is critical to our understanding of these diseases and optimization of the clinical benefits of our increasing knowledge in neuroimmunology.
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Affiliation(s)
- Stanley J Naides
- Immunology R&D, Quest Diagnostics Nichols Institute, 33608 Ortega Highway, San Juan Capistrano, CA 92675, USA.
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