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Nuclear membrane proteins are present within rimmed vacuoles in inclusion-body myositis

Steven A Greenberg1, Jack L Pinkus, Anthony A Amato

  • 1Department of Neurology, Division of Neuromuscular Disease, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. sagreenberg@partners.org

Muscle & Nerve
|July 11, 2006
PubMed

Insights

Rimmed vacuoles in inclusion-body myositis (IBM) originate from myonuclear breakdown. This study confirms that IBM

Area of Science:

  • Neurology
  • Cell Biology
  • Muscle Pathology

Background:

  • Rimmed vacuoles in inclusion-body myositis (IBM) are of uncertain origin.
  • Two hypotheses exist: abnormal lysosomal function or myonuclear breakdown.
  • Investigating the origin of these vacuoles is crucial for understanding IBM.

Purpose of the Study:

  • To test the hypothesis that rimmed vacuoles in IBM form due to myonuclear breakdown.
  • To differentiate the pathogenesis of IBM from other inflammatory myopathies.

Main Methods:

  • Studied muscle samples from 14 IBM patients and 18 controls.
  • Utilized immunohistochemistry for nuclear membrane proteins.
  • Performed semithin section analysis and electron microscopy.

Main Results:

  • IBM muscle vacuoles showed immunoreactivity for inner nuclear membrane proteins emerin and lamin A/C.
  • Fragmented or absent myonuclear membranes were observed in IBM muscle.
  • Confirmed the association of nuclear membrane proteins with rimmed vacuoles.

Conclusions:

  • Rimmed vacuoles in IBM are definitively linked to myonuclear pathology.
  • Inclusion-body myositis exhibits prominent myonuclear abnormalities, distinguishing it from other inflammatory myopathies.

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