银杏叶提取物对酒精所致大鼠骨骼肌损伤的保护和治疗的作用

目的探讨银杏叶提取物(EGB761)对酒精所致大鼠骨骼肌损伤的保护及治疗作用。方法SD大鼠70只共分四组:对照组10只,酒精组20只,EGB20只,EGB预防+治疗组20只。流式细胞计数仪检测各组大鼠跖肌的细胞凋亡率,分光光度法检测丙二醛(MDA)含量,超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)和诱导型一氧化氮合酶(iNOS)活性的变化。结果与对照组相比,酒精组的细胞凋亡率、跖肌的MDA含量和iNOS活性升高,SOD和GSH-Px活性下降。EGB干预后,细胞凋亡率较酒精组下降,跖肌的MDA含量和iNOS活性降低下降,SOD、GSH-Px活性升高。EGB761预防配合治疗的效果优于单纯治疗的效果。结论EGB761对酒精所致大鼠骨骼肌损伤的保护及治疗作用的机制可能与其对骨骼肌细胞凋亡率,MDA,SOD,GSH-Px和iNOS的调节有关。     

Cardiac ankyrin repeat protein is preferentially induced in atrophic myofibers of congenital myopathy and spinal muscular atrophy

Cardiac ankyrin repeat protein (CARP), which is structurally characterized by the presence of four ankyrin repeat motifs in its central region, is believed to be localized in the nucleus and to participate in the regulation of cardiac-specific gene expression in cardiomyocytes. However, we recently found that CARP was induced in skeletal muscle by denervation, leading us to speculate that CARP may be induced under some pathological conditions. In the present study, we immunohistochemically analyzed the expression of CARP in 11 cases of spinal muscular atrophy (SMA) and 14 cases of congenital myopathy. In SMA, CARP was expressed selectively in severely atrophic myofibers, suggesting that CARP expression may reflect the status of muscle atrophy. Furthermore, in the congenital myopathies, the expression patterns of CARP were distinct among the subtypes, which included nemaline myopathy, myotubular myopathy, central core disease, and congenital fiber type disproportion. Although CARP was preferentially expressed in severely damaged myofibers in nemaline myopathy, it was not detected in central core disease. These findings suggest that immunohistochemical evaluation of CARP may be helpful in the diagnosis of SMA and the congenital myopathies.     

Chronic progressive external ophthalmoplegia with inflammatory myopathy

Chronic progressive external ophthalmoplegia is one of mitochondrial disorders, characterized by ptosis, limitation of eye movement, variably severe bulbar muscle weakness and proximal limb weakness. Chronic progressive external ophthalmoplegia complicated with acquired disease is extremely rare. We report a 44 years old male patient with more than 20 years of chronic progressive bilateral ptosis and limitation of eye movements manifested dysarthria, dysphagia and neck muscle weakness for 3 years. The first muscle biopsy showed red-ragged fibers and cytochrome c oxidase negative fibers as well as inflammatory cells infiltration. Electron microscopy revealed paracrystalline inclusions. Mitochondrial genetic analysis demonstrated a large-scale mtDNA deletion of m.8470_13446del4977. The patient was treated with prednisone. In a three-year follow-up study, the second biopsy was performed. Before the treatment, except bilateral ptosis and external ophthalmopelgia, this patient presented bulbar muscle weakness and neck muscle weakness. After treated with prednisone, the symptoms of dysphagia, dysarthria and neck muscle weakness were significantly improved, and the second biopsy showed only mitochondrial myopathy pathology but the inflammations disappeared. Here, we report a patient with chronic progressive external ophthalmoplegia complicated with inflammatory myopathy and after treated with prednisone as myositis, he had a significant therapeutic effect.     

Gain‐of‐Function Mutation in STIM1 (P.R304W) Is Associated with Stormorken Syndrome

Stormorken syndrome is a rare autosomal dominant disorder characterized by a phenotype that includes miosis, thrombocytopenia/thrombocytopathy with bleeding time diathesis, intellectual disability, mild hypocalcemia, muscle fatigue, asplenia, and ichthyosis. Using targeted sequencing and whole‐exome sequencing, we identified the c.910C > T transition in a STIM1 allele (p.R304W) only in patients and not in their unaffected family members. STIM1 encodes stromal interaction molecule 1 protein (STIM1), which is a finely tuned endoplasmic reticulum Ca²⁺ sensor. The effect of the mutation on the structure of STIM1 was investigated by molecular modeling, and its effect on function was explored by calcium imaging experiments. Results obtained from calcium imaging experiments using transfected cells together with fibroblasts from one patient are in agreement with impairment of calcium homeostasis. We show that the STIM1 p.R304W variant may affect the conformation of the inhibitory helix and unlock the inhibitory state of STIM1. The p.R304W mutation causes a gain of function effect associated with an increase in both resting Ca²⁺ levels and store‐operated calcium entry. Our study provides evidence that Stormorken syndrome may result from a single‐gene defect, which is consistent with Mendelian‐dominant inheritance.     

How much mutant protein is needed to cause a protein aggregate myopathy in vivo? Lessons from an exceptional desminopathy

Myofibrillar myopathies are caused by mutations in desmin, B‐crystallin, myotilin, ZASP, and filamin genes. Since the vast majority of myofibrillar myopathy causing mutations are heterozygous single amino acid substitutions or small in‐frame deletions, the pathogenic role of mutant versus wild‐type protein cannot be assessed in human skeletal muscle by standard immunodetection techniques. We report on an exceptional desminopathy due to a heterozygous c.735G>C mutation. Immunoblotting detected full‐length 53desmin and a truncated 50variant in skeletal muscle from three affected patients of two different families. RT‐PCR identified three desmin mRNA species encoding for wild‐type and two mutant proteins, p.Glu245Asp and p.Asp214_Glu245del. Since previous functional studies on the p.Glu245Asp mutant showed biological properties identical to wild‐type desmin, the truncated p.Asp214_Glu245del desmin is the disease‐causing mutant. Semiquantitative RT‐PCR established a fraction of the truncated desmin mRNA species in a range from 24% to 37%. Initial quantification of corresponding desmin proteins in the muscle biopsy of the index patient of one family indicated a fraction of only 10% of the truncated species. However, serial analyses of different sections from each muscle biopsy revealed a high intra‐ and interindividual variability of the truncated desmin protein level within a range from 5% to 43%. Desmin assembly studies in vitro have established clear‐cut pathogenic ratios of mutant versus wild‐type proteins. However, our findings point out a far more complex situation in human skeletal muscle. The heterogeneously distributed mutation load within and between individual specimens, which reflects local differences in the expression and/or turnover of the mutant protein in different areas containing multiple myonuclear domains, renders it impossible to define an exact pathogenic threshold of a specific mutant in vivo. © 2008 Wiley‐Liss, Inc.     

Mutation analysis of the GNE gene in Korean patients with distal myopathy with rimmed vacuoles

Distal myopathy with rimmed vacuoles (DMRV; MIM 605820) is an autosomal recessive neuromuscular disorder characterized by weakness of the anterior compartment of the lower limbs, sparing the quadriceps muscles. Recently, mutations in the UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE) gene have been identified as the genetic basis of DMRV. To investigate the mutation spectrum of the GNE gene in Korean patients with DMRV, we performed clinical and genetic analysis of nine unrelated patients suspected to have DMRV. Direct sequencing analysis revealed that eight out of nine patients (88.9%) were either homozygous or compound heterozygous for GNE gene mutations, including three known (C13S, R129Q, and V572L) and two novel mutations (M29T and A591P). The allelic frequencies of the V572L and C13S mutations were 68.8% (11/16) and 12.5% (2/16), respectively. These results suggest that screening for GNE gene mutations in patients suspected to have DMRV would be helpful for molecular diagnosis of DMRV in the Korean population. An erratum to this article can be found at     

Autopsy case of desminopathy involving skeletal and cardiac muscle

Desminopathy is a familial or sporadic skeletal and cardiac muscular dystrophy caused by mutation in the desmin gene. Desmin-reactive deposits in the affected muscles are the morphological hallmarks of this disease. Herein is reported an autopsy case of a 57-year-old Japanese man with adult-onset skeletal muscle weakness and atrioventricular (A-V) conducting block, with a missense A337P mutation in exon 5 of the desmin gene. Disease onset occurred when the patient was 45 years old. The initial presentation was lower limb weakness, and the weakness progressed to the upper limbs. When the patient was 51 years old, a cardiac pacemaker was implanted due to complete A-V block. When the patient was 53 years old, respiratory insufficiency occurred due to weakness of respiratory muscles, and the patient died at the age of 57 years. On autopsy, intrasarcoplasmic desmin-immunoreactive deposits were identified in the skeletal and cardiac muscle, and abnormal accumulations of granulofilamentous material were identified at the ultrastructural level. In the cardiac conducting system, calcification was observed at the bundle of His, and sporadic calcium deposits were observed at the left and right bundle branches.     

Tubular aggregate myopathy and Stormorken syndrome: Mutation spectrum and genotype/phenotype correlation

Calcium (Ca²⁺) acts as a ubiquitous second messenger, and normal cell and tissue physiology strictly depends on the precise regulation of Ca²⁺ entry, storage, and release. Store‐operated Ca²⁺ entry (SOCE) is a major mechanism controlling extracellular Ca²⁺ entry, and mainly relies on the accurate interplay between the Ca²⁺ sensor STIM1 and the Ca²⁺ channel ORAI1. Mutations in STIM1 or ORAI1 result in abnormal Ca²⁺ homeostasis and are associated with severe human disorders. Recessive loss‐of‐function mutations impair SOCE and cause combined immunodeficiency, while dominant gain‐of‐function mutations induce excessive extracellular Ca²⁺ entry and cause tubular aggregate myopathy (TAM) and Stormorken syndrome (STRMK). TAM and STRMK are spectra of the same multisystemic disease characterized by muscle weakness, miosis, thrombocytopenia, hyposplenism, ichthyosis, dyslexia, and short stature. To date, 42 TAM/STRMK families have been described, and here we report five additional families for which we provide clinical, histological, ultrastructural, and genetic data. In this study, we list and review all new and previously reported STIM1 and ORAI1 cases, discuss the pathomechanisms of the mutations based on the known functions and the protein structure of STIM1 and ORAI1, draw a genotype/phenotype correlation, and delineate an efficient screening strategy for the molecular diagnosis of TAM/STRMK.     

Immune-mediated statin myopathy

Statin-induced necrotizing autoimmune myopathy (SINAM) is associated with a unique clinical 5 phenotype of severe proximal muscle weakness during or after exposure to statins in patients with high creatine kinase (CK) levels. Electromyography (EMG) and muscle biopsy reveal features of a necrotizing myopathy and the anti-HMGCR autoantibody is frequently detected. Treatment requires a combination of statin discontinuation as well as immunomodulatory or immunosuppressive therapy. HLA typing (HLADRB1*1101) is strongly associated with anti-10 HMGCR autoantibody positivity in statin-exposed patients. It is well documented that statin triggers autoimmune disease in those with a genetic susceptibility. With the commercial availability of an accurate ELISA test, the natural history of the disease and its phenotypic features are becoming increasingly understood.