Incidence of polysaccharide storage myopathy in draft horse-related breeds: a necropsy study of 37 horses and a mule.
Abstract: Skeletal muscle samples from 38 draft horse-related animals 1-23 years of age were evaluated for evidence of aggregates of glycogen and complex polysaccharide characteristic of equine polysaccharide storage myopathy (EPSSM). Cardiac muscle from 12 of these horses was also examined. Antemortem serum levels of creatine kinase (CK) and aspartate aminotransferase (AST) from 9 horses with EPSSM and 5 horses without EPSSM were compared. Skeletal muscle from 17 horses contained inclusions of periodic acid-Schiff (PAS)-positive, amylase-resistant complex polysaccharide. Similar inclusions were also present in the cardiac muscle of 1 horse. A vacuolar myopathy with aggregates of PAS-positive, amylase-sensitive glycogen was seen in 8 other horses, and these findings are also considered diagnostic for EPSSM. Antemortem serum activities of CK and AST were often higher in EPSSM horses than in horses without EPSSM. Using the presence of amylase-resistant complex polysaccharide as the criterion for diagnosis of EPSSM, the incidence in this population was 45%. Inclusion of horses with aggregates of glycogen but no amylase-resistant complex polysaccharide as representative of the range of pathologic findings in horses with EPSSM resulted in a 66% incidence in this population.
Publication Date: 2001-03-13 PubMed ID: 11243365DOI: 10.1177/104063870101300112Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Aspartate Aminotransferase (AST)
- Clinical Pathology
- Creatine Kinase
- Diagnosis
- Diagnostic Technique
- Disease
- Disease Diagnosis
- Draft Horses
- Epidemiology
- Equine Diseases
- Equine Health
- Glycogen
- Horses
- Mule
- Muscle
- Musculoskeletal System
- Necropsy
- Pathology
- Polysaccharide Storage Myopathy
- Veterinary Medicine
- Veterinary Research
Summary
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The study investigates the occurrence of equine polysaccharide storage myopathy (EPSSM), a muscle disease in horses, in 38 draft horse-related animals, comparing the antemortem serum levels of certain enzymes in affected and non-affected horses. It is found that polysaccharide storage myopathy has up to a 66% incidence in the studied population.
Objective of The Research
- The research aimed to evaluate the occurrence of equine polysaccharide storage myopathy (EPSSM) in a select group of draft horse-related animals. EPSSM is a muscle disease in horses characterized by the accumulation of abnormal glycogen (storage form of glucose) and other complex polysaccharides in muscle cells.
Research Methodology
- The study utilized skeletal muscle samples from 38 animals, ranging from 1-23 years of age, associated with draft horses.
- For some animals, cardiac muscle was also examined.
- To differentiate between horses with and without EPSSM, the antemortem serum levels (levels of certain substances in the blood before death) of creatine kinase (CK) and aspartate aminotransferase (AST), both of which are enzymes, were compared.
- The researchers based their EPSSM diagnoses on the presence of an amylase-resistant complex polysaccharide—a type of carbohydrate that does not break down with the enzyme amylase.
Findings
- Of the horses studied, 17 showed inclusions of amylase-resistant complex polysaccharides in their skeletal muscles.
- A vacuolar myopathy, another form of muscle disorder characterized by aggregates of glycogen, was found in 8 different horses. These findings were also marked as diagnostic for EPSSM.
- Often, the serum activities of CK and AST were higher in horses with EPSSM than in horses without the disease.
Conclusion
- Using the presence of amylase-resistant complex polysaccharides as the metric for diagnosis, the incidence of EPSSM in the studied draft horse-related population was 45%.
- Upon the inclusion of horses that had aggregates of glycogen but no amylase-resistant complex polysaccharides, as indicative of a range of pathological outcomes in EPSSM horses, the incidence rate rose to 66%.
Cite This Article
APA
Valentine BA, Habecker PL, Patterson JS, Njaa BL, Shapiro J, Holshuh HJ, Bildfell RJ, Bird KE.
(2001).
Incidence of polysaccharide storage myopathy in draft horse-related breeds: a necropsy study of 37 horses and a mule.
J Vet Diagn Invest, 13(1), 63-68.
https://doi.org/10.1177/104063870101300112 Publication
Researcher Affiliations
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis 97331, USA.
MeSH Terms
- Amylases / analysis
- Amylases / metabolism
- Animals
- Autopsy / veterinary
- Carbohydrate Metabolism
- Carbohydrate Metabolism, Inborn Errors / epidemiology
- Carbohydrate Metabolism, Inborn Errors / pathology
- Carbohydrate Metabolism, Inborn Errors / veterinary
- Female
- Glycogen / analysis
- Glycogen / metabolism
- Horse Diseases / pathology
- Horses
- Incidence
- Male
- Muscle, Skeletal / pathology
- Muscular Diseases
Citations
This article has been cited 2 times.- McCue ME, Valberg SJ, Miller MB, Wade C, DiMauro S, Akman HO, Mickelson JR. Glycogen synthase (GYS1) mutation causes a novel skeletal muscle glycogenosis. Genomics 2008 May;91(5):458-66.
- Lindsay-McGee V, Massey C, Li YT, Clark EL, Psifidi A, Piercy RJ. Characterisation of phenotypic patterns in equine exercise-associated myopathies. Equine Vet J 2025 Mar;57(2):347-361.
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