Proton magnetic resonance spectroscopy of the intrinsic tongue muscles in patients with myasthenia gravis with different autoantibodies

Lavrnić, Dragana; Daković, Marko; Perić, Stojan; Rakočević-Stojanović, Vidosava; Basta, Ivana; Marjanović, Ivan; Stošić-Opinćal, Tatjana; Lavrnić, Slobodan

doi:10.1016/j.jns.2010.12.009

Cited by 4 publications

(5 citation statements)

References 24 publications

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“…The characteristics of the tongue MRS findings in patients with MG, according to their antibody status, have already been published [5]. In the present study, MRS obtained from subject with MuSK MG showed prominent resonance at 1.33 ppm arising from protons in methylene groups of lipids (PMN peak) and visible PML peak from methyl protons at 0.9 ppm.…”

Section: Resultssupporting

confidence: 55%

“…Unlike AChR MG patients, in whom MRS highlighted the presence of fatty infiltration of the tongue due to the lipid migration from intra-into extramyocellular space, in patients with MuSK MG, the tendency toward increased saturated/unsaturated fat ratio has been observed and it could reflect intramyocellular lipid deposition in the tongue [5]. In our cohort of MuSK MG patients, this finding was present in 85 % of cases.…”

Section: Discussionmentioning

confidence: 48%

“…In patients with AChR MG, MRS highlights increased lipid content in the tongue muscles due to the lipid migration from intra-to extra-myocellular space. A tendency toward increased saturated/unsaturated fat ratio has been observed in patients with MuSK MG that could reflect intramyocellular lipid deposition in the tongue [5].…”

Section: Introductionmentioning

confidence: 96%

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Myopathy, muscle atrophy and tongue lipid composition in MuSK myasthenia gravis

et al. 2014

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Myasthenia gravis (MG) associated with anti-muscle-specific tyrosine kinase (MuSK) antibodies differs in many aspects from typical presentation of acetylcholine receptor (AChR)-positive MG. Myopathy and muscle atrophy are observed in MuSK-positive MG patients, unlike AChR-positive patients with MG. That is why the aim of this study was to assess the presence of myopathy and muscle atrophy as well as the tongue lipid composition in our cohort of MuSK-positive MG patients. Clinical examination, electromyography (EMG) and proton magnetic resonance spectroscopy were performed in 31 MuSK-positive and 28 AChR-positive MG patients. Myopathic EMG was more frequent in MuSK compared to AChR MG patients. In AChR MG patients, myopathic EMG in facial muscles was more frequent after long-term corticosteroid treatment, which was not the case with MuSK-positive MG patients. Facial and/or tongue muscle atrophy was registered in 23 % of MuSK MG patients. Longer disease duration was observed in patients with clinical signs of tongue and/or facial muscle atrophy compared to those with normal tongue muscle. Intramyocellular lipid deposition in the tongue was present in 85.2 % of MuSK and 20 % of AChR MG patients. Female MuSK MG patients had more frequently electrophysiological signs of myopathy on the facial muscles and signs of intramyocellular lipid deposition in the tongue, compared to male patients with MuSK-positive MG. Myopathy, muscle atrophy and intramyocellular lipid deposition in the tongue are more frequent in MuSK-positive compared to AChR-positive MG patients.

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Section: Resultssupporting

confidence: 55%

Section: Discussionmentioning

confidence: 48%

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Myopathy, muscle atrophy and tongue lipid composition in MuSK myasthenia gravis

et al. 2014

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“…Unlike symptoms in seropositive MG, many AMM patients have wasting of these muscles 7 , 9–17 . The data available, including those from electrophysiologic studies of the involved muscles and a small number of histologic studies of (less involved) extremity muscles, have failed to show evidence of denervation but rather suggested a myopathic process, perhaps involving mitochondrial function 8,11,15 , 18–23 . Other differences from MG include poor response to treatment with cholinesterase inhibitors, intravenous Ig, or thymectomy 3,6,24 .…”

Section: Antimuscle‐specific Kinase Myastheniamentioning

confidence: 99%

“…The mechanism of the development of the prominent axial muscle wasting in these patients remains unclear. The data available, including those from electrophysiologic studies of the involved muscles and a small number of histologic studies of (less involved) extremity muscles, failed to show evidence of denervation but instead suggested a myopathic process, perhaps involving mitochondrial function 8,11,15 , 18–23 . Such myopathic changes support a role for MuSK in mediating trophic effects on muscle, perhaps through complex two‐way communication between nerve and muscle at the NMJ.…”

Section: Muscle Wasting In Ammmentioning

confidence: 99%

Animal models of antimuscle‐specific kinase myasthenia

Richman

Nishi

Ferns

et al. 2012

Annals of the New York Academy of Sciences

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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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