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Autophagic vacuoles with sarcolemmal features delineate Danon disease and related myopathies

Kazuma Sugie1, Satoru Noguchi, Yoshimichi Kozuka

  • 1Department of Neuromuscular Research, National Institute of Neuroscience, National Hospital for Mental Nervous and Muscular Disorders, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.

Journal of Neuropathology and Experimental Neurology
|June 28, 2005
PubMed

Insights

Autophagic vacuolar myopathies (AVMs) with sarcolemmal features (AVSF) represent a distinct subgroup. AVSF are autolysosomes with a secondary sarcolemma-like structure, aiding in AVM classification.

Area of Science:

  • Neuropathology
  • Muscle Diseases
  • Cell Biology

Background:

  • Autophagic vacuolar myopathies (AVMs) encompass diverse muscle disorders.
  • A subset of AVMs is characterized by autophagic vacuoles with sarcolemmal features (AVSF).
  • The diagnostic significance and formation mechanism of AVSF remain unclear.

Purpose of the Study:

  • To elucidate the detailed morphologic features of AVSF in AVMs.
  • To investigate the relationship between AVSF and autolysosomes.
  • To understand the formation process of AVSF.

Main Methods:

  • Histologic and ultrastructural examination of muscle biopsies from patients with AVMs.
  • Light microscopy to identify autophagic vacuoles and AVSF.
  • Electron microscopy to analyze the ultrastructure of vacuoles and surrounding membranes.
  • Immunohistochemistry for sarcolemmal proteins and acetylcholinesterase activity.

Main Results:

  • AVSF were identified as autolysosomes enclosed by membranes containing sarcolemmal proteins and acetylcholinesterase.
  • In Danon disease, AVSF increased with age, while autolysosomes decreased, suggesting secondary formation.
  • AVSF formation appeared to occur in situ, forming enclosed spaces, distinct from other AVMs.

Conclusions:

  • AVSF with acetylcholinesterase activity represent a specific type of autolysosome with a secondary intracytoplasmic sarcolemma-like structure.
  • AVSF delineate a distinct subgroup of autophagic vacuolar myopathies.
  • Understanding AVSF aids in the classification and diagnosis of specific AVMs.

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