Innervation of dystrophic muscle after muscle stem cell therapy

Introduction: Duchenne muscular dystrophy (DMD) is caused by loss of the structural protein, dystrophin, resulting in muscle fragility. Muscle stem cell (MuSC) transplantation is a potential therapy for DMD. It is unknown whether donor‐derived muscle fibers are structurally innervated. Methods: Green fluorescent protein (GFP)–expressing MuSCs were transplanted into the tibials anterior of adult dystrophic mdx/mTR mice. Three weeks later the neuromuscular junction was labeled by immunohistochemistry. Results: The percent overlap between pre‐ and postsynaptic immunolabeling was greater in donor‐derived GFP⁺ myofibers, and fewer GFP⁺ myofibers were identified as denervated compared with control GFP^– fibers (P = 0.001 and 0.03). GFP⁺ fibers also demonstrated acetylcholine receptor fragmentation and expanded endplate area, indicators of muscle reinnervation (P = 0.008 and 0.033). Conclusion: It is unclear whether GFP⁺ fibers are a result of de novo synthesis or fusion with damaged endogenous fibers. Either way, donor‐derived fibers demonstrate clear histological innervation. Muscle Nerve 54 : 763–768, 2016     

Imaging Flow Cytometry Analysis to Identify Differences of Survival Motor Neuron Protein Expression in Patients With Spinal Muscular Atrophy

BackgroundSpinal muscular atrophy is a neurodegenerative disorder caused by the deficient expression of survival motor neuron protein in motor neurons. A major goal of disease-modifying therapy is to increase survival motor neuron expression. Changes in survival motor neuron protein expression can be monitored via peripheral blood cells in patients; therefore we tested the sensitivity and utility of imaging flow cytometry for this purpose.MethodsAfter the immortalization of peripheral blood lymphocytes from a human healthy control subject and two patients with spinal muscular atrophy type 1 with two and three copies of SMN2 gene, respectively, we used imaging flow cytometry analysis to identify significant differences in survival motor neuron expression. A bright detail intensity analysis was used to investigate differences in the cellular localization of survival motor neuron protein.ResultsSurvival motor neuron expression was significantly decreased in cells derived from patients with spinal muscular atrophy relative to those derived from a healthy control subject. Moreover, survival motor neuron expression correlated with the clinical severity of spinal muscular atrophy according to SMN2 copy number. The cellular accumulation of survival motor neuron protein was also significantly decreased in cells derived from patients with spinal muscular atrophy relative to those derived from a healthy control subject.ConclusionsThe benefits of imaging flow cytometry for peripheral blood analysis include its capacities for analyzing heterogeneous cell populations; visualizing cell morphology; and evaluating the accumulation, localization, and expression of a target protein. Imaging flow cytometry analysis should be implemented in future studies to optimize its application as a tool for spinal muscular atrophy clinical trials.     

Spinal muscular atrophy with respiratory distress syndrome (SMARD1): Case report and review of literature

Spinal muscular atrophy with respiratory distress syndrome (SMARD1) is a rare cause of early infantile respiratory failure and death. No cases have been currently described from India. Two low-birth-weight infants presented prior to 6 months of age with recurrent apnea and respiratory distress. Both required prolonged ventilation, and had distal arthrogryposis and diaphragmatic eventration. Nerve conduction study revealed motor sensory axonopathy. Genetic testing confirmed mutations in immunoglobulin mu binding protein (IGHMBP2). These two cases establish presence of SMARD1 in our population. Both infants died on discontinuation of ventilation. Antenatal diagnoses done in one pregnancy. Though rare, high index of suspicion is essential in view of poor outcome and aid antenatal counseling.     

肯尼迪病3个家系的临床、基因型和遗传特征分析

目的分析3个肯尼迪病(Kennedy disease,KD)家系的临床、基因及遗传特征。方法收集3个KD家系患者的详细病史、体格检查、血生化及电生理检查等资料,用基因分析的方法测定先证者及家族成员雄性激素受体(androgen receptor,AR)基因的CAG重复序列拷贝数。结果 3个家系发现的5例KD患者主要临床表现为四肢肌肉萎缩、无力和肢体震颤,舌肌萎缩、纤颤;实验室检查发现肌酸激酶升高;肌电图检查可见失神经电位;神经传导速度检查提示感觉神经受损。KD患者AR基因CAG重复次数在42~49。3个家系的遗传方式符合X连锁隐性遗传。结论 KD主要影响男性患者,病情缓慢进展,主要表现为脊髓和延髓肌肉的萎缩和无力。基因检测有助确诊,并可检测出携带者,以进行家系遗传分析。     

Kennedy病的临床、电生理和遗传学特点

目的探讨Kennedy病的临床、电生理及遗传学特点。方法对4例Kennedy病患者的临床资料进行回顾性分析。结果 4例患者均为中年男性,缓慢起病。首发症状为双下肢无力2例,咀嚼肌无力2例。主要临床表现为四肢进行性无力,肌肉萎缩,下肢相对较重,进展缓慢;4例患者均有肌束震颤,舌肌萎缩;乳房女性化3例,性功能减退2例。4例均有血清肌酸激酶增高,3例血脂增高、性激素水平升高,1例甲状腺功能异常。EMG表现为广泛的神经源性损害。4例患者的雄激素受体基因第一外显子CAG重复数为45~52。结论 Kennedy病是相对进展缓慢的四肢近端、延髓肌受累,以及内分泌和代谢异常的遗传性神经系统变形疾病,本病的确诊有赖于雄激素受体基因第一外显子CAG重复数的检测。     

α-Sarcoglycanopathy的临床和病理学特征(附2例报告)

目的探讨α-Sarcoglycanopathy的临床和病理学特征。方法回顾性分析2例α-Sarcoglycanopathy患者的临床资料。结果本组2例患者均表现为近端肌肉无力,进行性加重。肌肉活检均可见肌间结缔组织及脂肪组织增生,肌纤维萎缩,偶见肌纤维变性、坏死和吞噬现象,未见炎细胞浸润;免疫组化染色示抗α-Sarcoglycan蛋白完全缺失,抗β、γ、δ-sacogiycan蛋白和抗dystrophin蛋白部分缺失。结论α-Sarcoglycanopathy临床表现较其他类型肌营养不良无特异性,病理学特征为免疫组化染色示抗α-Sarcoglycan蛋白完全缺失。     

关节挛缩伴强直脊柱综合征1例报道并文献复习

目的报道1例以关节挛缩伴强直脊柱综合征为主要表现的肢带型肌营养不良2A(LGMD2A)病例,提高对以关节挛缩及强直脊柱综合征为主要表型的肌肉疾病的认识。方法收集1例以关节挛缩伴强直脊柱综合征为表征最终确诊为LGMD2A患者的临床资料、肌肉活检(病理染色、Western blot)、基因检测和肌肉影像学等资料,结合文献复习进行分析。结果患者除早期出现的全身关节挛缩伴强直脊柱外,合并有四肢近端肌肉萎缩、无力,明显翼状肩。家族史提示常染色体隐性或X连锁隐性遗传可能;肌肉MRI示大腿后群、内侧群,小腿后群显著受累;肌肉病理检查示肌营养不良表现;Western blot检测示calpain-3条带完全缺失,CAPN3基因检测示患者携带c.534AG(I178M)及c.411dupC(C137fs)双杂合突变,并均为新发突变。最终诊断为LGMD2A。结论临床中对于早发关节挛缩伴强直脊柱综合征的患者,需考虑LGMD2A可能,肌肉MRI可为LGMD2A的诊断和鉴别诊断提供重要线索。     

The potential of psychological interventions to improve quality of life and mood in muscle disorders

Quality of life (QoL) and mood are reduced in many patients with muscle disorders. Psychological variables appear to be contributors to both QoL and mood, suggesting that psychological interventions could improve these outcomes, yet research in this area is sparse. We review the roles of psychological variables, plus context and disease severity, in explaining QoL. A cognitive‐behavioral model of disease self‐management, with acceptance as the central component, is discussed. This model is then used to describe how psychological interventions derived from cognitive behavioral therapy (CBT), in particular Acceptance and Commitment Therapy (ACT), might be applied to address the issues of distress, nonadherence to treatments, pain, and fatigue in people with muscle disorders. Muscle Nerve 52 : 131–136, 2015     

Outcome reliability in non‐Ambulatory Boys/Men with duchenne muscular dystrophy

Introduction: Therapeutic trials in Duchenne muscular dystrophy (DMD) often exclude non‐ambulatory individuals. Here we establish optimal and reliable assessments in a multicenter trial. Methods: Non‐ambulatory boys/men with DMD (N = 91; 16.7 ± 4.5 years of age) were assessed by trained clinical evaluators. Feasibility (percentage completing task) and reliability [intraclass correlation coefficients (ICCs) between morning and afternoon tests] were measured. Results: Forced vital capacity (FVC), assessed in all subjects, showed a mean of 47.8 ± 22% predicted (ICC 0.98). Brooke Upper Extremity Functional Rating (Brooke) and Egen Klassifikation (EK) scales in 100% of subjects showed ICCs ranging from 0.93 to 0.99. Manual muscle testing, range of motion, 9‐hole peg test, and Jebsen‐Taylor Hand Function Test (JHFT) demonstrated varied feasibility (99% to 70%), with ICCs ranging from 0.99 to 0.64. We found beneficial effects of different forms of corticosteroids for the Brooke scale, percent predicted FVC, and hand and finger strength. Conclusions: Reliable assessment of non‐ambulatory boys/men with DMD is possible. Clinical trials will have to consider corticosteroid use. Muscle Nerve 51: 522–532, 2015     

AANEM news and comments

Introduction: With clinical trials underway, our objective was to construct a composite score of global function that could discriminate among people with spinal muscular atrophy (SMA). Methods: Data were collected from 126 participants with SMA types 2 and 3. Scores from the Hammersmith Functional Motor Scale—Expanded and Upper Limb Module were expressed as a percentage of the maximum score and 6‐minute walk test as percent of predicted normal distance. A principal component analysis was performed on the correlation matrix for the 3 percentage scores. Results: The first principal component yielded a composite score with approximately equal weighting of the 3 components and accounted for 82% of the total variability. The SMA functional composite score, an unweighted average of the 3 individual percentage scores, correlated almost perfectly with the first principal component. Conclusions: This combination of measures broadens the spectrum of ability that can be quantified in type 2 and 3 SMA patients. Muscle Nerve 52 : 942–947, 2015