Light and electron microscopic localization of beta-amyloid protein in muscle biopsies of patients with inclusion-body myositis
In 11 of 11 inclusion-body myositis (IBM) patients, including one hereditary case, vacuolated muscle fibers contained large and multiple small inclusions immunoreactive for beta-amyloid protein (beta AP). All IBM muscle biopsies had characteristic cytoplasmic tubulo-filaments (CTFs) by electron micr...
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Published in | The American journal of pathology Vol. 141; no. 1; pp. 31 - 36 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Bethesda, MD
ASIP
01.07.1992
American Society for Investigative Pathology |
Subjects | |
Online Access | Get full text |
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Summary: | In 11 of 11 inclusion-body myositis (IBM) patients, including one hereditary case, vacuolated muscle fibers contained large and multiple small inclusions immunoreactive for beta-amyloid protein (beta AP). All IBM muscle biopsies had characteristic cytoplasmic tubulo-filaments (CTFs) by electron microscopy. None of 14 control muscle biopsies contained the beta AP immunoreactive (IR) inclusions characteristic of IBM. On the light microscopy level, beta AP-IR inclusions colocalized with ubiquitin immunoreactivity. By immunogold electronmicroscopy, beta AP immunoreactivity was localized to a) amorphous, poorly defined structures, b) dense floccular material, c) clusters of loosely packed amyloidlike fibrils 6-8 nm in diameter, and d) poorly defined loose fibrillar structures 6-8 nm in diameter. beta AP immunoreactive structures were often in proximity to CTFs, but CTFs themselves never contained beta AP-IR. Our study provides the first demonstration of beta AP accumulations in abnormal human muscle. This finding suggests that in addition to Alzheimer's disease, Down syndrome, and Dutch-type hereditary cerebrovascular amyloidosis, beta AP may play an important role in the pathogenesis of other diseases, including ones outside the central nervous system, for example, IBM. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0002-9440 1525-2191 |