Comparative Skeletal Muscle Histopathologic and Ultrastructural Features in Two Forms of Polysaccharide Storage Myopathy in Horses
Comparative Skeletal Muscle Histopathologic and Ultrastructural Features in Two Forms of Polysaccharide Storage Myopathy in Horses
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DOI：
10.1354/vp.08-vp-0177-m-fl
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发表时间：
2009-11-01
影响因子：
2.4
通讯作者：
Valberg, S. J.
中科院分区：
文献类型：
--
作者：
McCue, M. E.;Armien, A. G.;Valberg, S. J.
多糖储存性肌病（PSSM）已经在超过35种不同的马品种中发现，通过在肌肉活检中鉴定异常储存或多糖。糖原合成酶I基因（GYS1）的显性突变在至少17个品种的PSSM病例中占相当大的比例，包括四分之一马，但一些通过肌肉组织病理学分析诊断为PSSM的马对该突变呈阴性。我们假设在gys1阴性的PSSM马中存在第二种不同形式的糖原储存病。本研究的目的是比较gys1阴性的四分之一马及相关品种的PSSM与gys1阳性的PSSM的组织病理学特征、多糖的超微结构、信号、历史和症状。53匹gys1阴性马的骨骼肌冷冻切片用苏木精和伊红、周期性酸希夫（PAS）和淀粉酶-PAS染色的总组织病理学评分与52匹gys1阳性马的组织病理学评分没有差异。异常多糖在外观上呈细颗粒状或均匀（49/53;92%），通常是淀粉酶敏感（28/53;53%），在gys1阴性的马中更常位于肌膜下，由β糖原颗粒组成。然而，在gys1阳性的马中，异常多糖通常为粗颗粒状（50/52;96%），淀粉酶抗性（51/52;98%），更常见的是细胞质，由β糖原颗粒组成，或者在一些肌纤维中，由β糖原颗粒包围的丝状物质组成。回顾性分析发现，gys1阴性的马（n = 43）在出现时更年轻（4.9 +/- 0.6岁，而gys1阳性的马为6.7 +/- 0.3岁），并且比gys1阳性的马（n = 160）更可能是完整的雄性。我们认为PSSM存在两种形式，并且通常具有独特的异常多糖。然而，由于对多糖的组织学表现的评估是主观的，并受年龄的影响，目前诊断PSSM的金标准似乎是对GYS1突变进行检测，然后对那些突变阴性的马进行肌肉活检，以检查其特征性异常多糖。
Polysaccharide storage myopathy (PSSM) has been found in more than 35 different horse breeds through identification of abnormal storage or polysaccharide in muscle biopsies. A dominant mutation in the glycogen synthase I gene (GYS1) accounts for a substantial proportion of PSSM cases in at least 17 breeds, including Quarter Horses, but some horses diagnosed with PSSM by muscle histopathologic analysis are negative For the mutation. We hypothesized that a second distinct form of glycogen storage disease exists in GYS1-negative horses with PSSM. The objectives of this Study were to compare the histopathologic features, ultrastructure of polysaccharide, signalment, history, and presenting complaints of GYS1-negative Quarter Horses and related breeds with PSSM to those of GYS1-positive horses with PSSM. The total histopathologic score in frozen sections of skeletal muscle stained with hematoxylin and eosin, periodic acid Schiff (PAS) and amylase-PAS stains from 53 GYS1-negative horses did not differ from that of 52 GYS1-positive horses. Abnormal polysaccharide was fine granular or homogenous in appearance (49/53; 92%), often amylase-sensitive (28/53; 53%), more commonly located under the sarcolemma, and consisting of beta glycogen particles in GYS1-negative horses. However, in GYS1-positive horses, abnormal polysaccharide was usually coarse granular (50/52; 96%), amylase-resistant (51/52; 98%), more commonly cytoplasmic, and consisting of beta glycogen particles or, in some myofibers, filamentous material surrounded by beta glycogen particles. Retrospective analysis found that GYS1-negative horses (n = 43) were younger at presentation (4.9 +/- 0.6 years vs. 6.7 +/- 0.3 years for GYS1-positive horses) and were more likely to be intact males than GYS1-positive horses (n = 160). We concluded that 2 forms of PSSM exist and often have distinctive abnormal polysaccharide. However, because evaluation of the histologic appearance of polysaccharide call be subjective and affected by age, the gold standard for diagnosis of PSSM at present would appear to be testing for the GYS1 mutation followed by evaluating muscle biopsy For characteristic abnormal polysaccharide in those horses that are negative for the mutation.