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Comparison of histopathologic criteria and skeletal muscle fixation techniques for the diagnosis of polysaccharide storage myopathy in horses.
Abstract: The purpose of the study reported here was to determine the effect of three methods of fixation of skeletal muscle biopsy specimens on the histopathologic appearance of muscle sections and to determine criteria that were most consistently associated with a diagnosis of polysaccharide storage myopathy (PSSM) in horses. Surgically excised semimembranosus muscle biopsy specimens were obtained from nine horses previously diagnosed with PSSM and from 15 control horses. Portions of each specimen were fixed in formalin, frozen immediately, and chilled for 24 hours prior to freezing. Sections stained with hematoxylin and eosin (HE), periodic acid-Schiff (PAS), and amylase-PAS were scored for histopathologic criteria by three investigators blinded to the sample origin. The presence of amylase-resistant, abnormal polysaccharide was found to be the most sensitive and specific diagnostic indicator for PSSM, and was readily detected regardless of the fixation technique or investigator. Other less-specific features associated with PSSM included atrophy and cytoplasmic and subsarcolemmal vacuoles; however, their histologic scores varied among fixation technique and investigators. Scores for subsarcolemmal and cytoplasmic amylase-sensitive glycogen in horses with PSSM were similar to those for control horses and varied among fixation techniques. In conclusion, PSSM is most accurately diagnosed in muscle biopsy specimens on the basis of appearance of amylase-resistant, abnormal polysaccharide, not amylase-sensitive glycogen, regardless of fixation technique. In general, frozen sections appeared to be better suited for studying myopathies because many histopathologic features of skeletal muscle were obscured by formalin fixation.
Publication Date: 2006-05-05 PubMed ID: 16672572DOI: 10.1354/vp.43-3-257Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article discusses a study exploring various methods of preserving muscle biopsy specimens and how these methods affect the diagnosis of polysaccharide storage myopathy (PSSM) in horses. The study defined the most accurate diagnostic indicator for PSSM to be the presence of amylase-resistant, abnormal polysaccharide, not amylase-sensitive glycogen, regardless of the preservation method applied.
Methods
- The research involved obtaining semimembranosus muscle biopsy specimens from nine horses previously diagnosed with PSSM and 15 control horses.
- The specimens were then subjected to three different methods of preservation: fixation in formalin, immediate freezing, and chilling for 24 hours before freezing.
Procedure
- The researchers then examined sections of the preserved specimens dyed with hematoxylin and eosin (HE), periodic acid-Schiff (PAS), and amylase-PAS.
- Three investigators scored the samples based on histopathologic criteria, without knowing the origin of the specimens.
Findings
- The study discovered that the presence of amylase-resistant, abnormal polysaccharide was the most consistent and sensitive diagnostic marker for PSSM, irrespective of the preservation method or investigator.
- Other less definitive features associated with PSSM include atrophy, and cytoplasmic and subsarcolemmal vacuoles, but their histologic scores varied depending on the preservation method and investigator.
- Scores for subsarcolemmal and cytoplasmic amylase-sensitive glycogen in horses with PSSM were similar to those for control horses and varied among fixation techniques.
Conclusion
- The research concluded that PSSM diagnosis is most accurate based on the appearance of amylase-resistant, abnormal polysaccharides, irrespective of the preservation method.
- Additionally, in most cases, it was found that frozen sections are more suitable for studying myopathies as many histopathologic features in skeletal muscles were obscured by formalin fixation.
Cite This Article
APA
Firshman AM, Valberg SJ, Bender JB, Annandale EJ, Hayden DW.
(2006).
Comparison of histopathologic criteria and skeletal muscle fixation techniques for the diagnosis of polysaccharide storage myopathy in horses.
Vet Pathol, 43(3), 257-269.
https://doi.org/10.1354/vp.43-3-257 Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA. Anna.Firshman@oregonstate.edu
MeSH Terms
- Animals
- Glycogen Storage Disease / diagnosis
- Glycogen Storage Disease / pathology
- Glycogen Storage Disease / veterinary
- Horse Diseases / diagnosis
- Horses
- Muscle, Skeletal / pathology
- Muscular Diseases / diagnosis
- Muscular Diseases / pathology
- Muscular Diseases / veterinary
- Polysaccharides / metabolism
- Tissue Fixation / methods
- Tissue Fixation / veterinary
Citations
This article has been cited 5 times.- Hannah WB, Derks TGJ, Drumm ML, Grünert SC, Kishnani PS, Vissing J. Glycogen storage diseases. Nat Rev Dis Primers 2023 Sep 7;9(1):46.
- Tan ET, Zochowski KC, Sneag DB. Diffusion MRI fiber diameter for muscle denervation assessment. Quant Imaging Med Surg 2022 Jan;12(1):80-94.
- Banse HE, Frank N, Kwong GP, McFarlane D. Relationship of oxidative stress in skeletal muscle with obesity and obesity-associated hyperinsulinemia in horses. Can J Vet Res 2015 Oct;79(4):329-38.
- Barrey E, Mucher E, Jeansoule N, Larcher T, Guigand L, Herszberg B, Chaffaux S, Guérin G, Mata X, Benech P, Canale M, Alibert O, Maltere P, Gidrol X. Gene expression profiling in equine polysaccharide storage myopathy revealed inflammation, glycogenesis inhibition, hypoxia and mitochondrial dysfunctions. BMC Vet Res 2009 Aug 7;5:29.
- Hansen S, Hopster-Iversen C, Berg L, Fjeldborg J, Massey C, Piercy RJ, Carstensen H. Chronic idiopathic myopathy in Icelandic horses: A case series. Equine Vet J 2025 Sep;57(5):1341-1346.
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