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Beta-amyloid formation by myocytes of leptomeningeal vessels

H M Wisniewski1, J Wegiel

  • 1Department of Pathological Neurobiology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314.

Acta Neuropathologica
|January 1, 1994
PubMed

Insights

Smooth muscle cells in Alzheimer's disease (AD) leptomeningeal vessels produce beta-amyloid deposits. These cells secrete beta-protein, which forms amyloid in the vessel wall, leading to cell death and vascular damage.

Area of Science:

  • Neuropathology
  • Vascular Biology
  • Alzheimer's Disease Research

Background:

  • Alzheimer's disease (AD) is characterized by beta-amyloid (Aβ) accumulation in the brain.
  • The role of vascular pathology in AD pathogenesis is increasingly recognized.
  • Leptomeningeal vessels are crucial for brain homeostasis and are affected in AD.

Purpose of the Study:

  • To investigate the cellular origin of beta-amyloid deposits in leptomeningeal vessels in Alzheimer's disease.
  • To elucidate the mechanism of amyloid formation within the vascular media.

Main Methods:

  • Ultrastructural analysis of leptomeningeal vessels from three Alzheimer's disease subjects.
  • Immunohistochemical staining to detect beta-amyloid.

Main Results:

  • Beta-amyloid deposits in the media of arteries and arterioles are produced by smooth muscle cells.
  • Smooth muscle cells secrete soluble beta-protein via sarcolemmal vesicles, which polymerizes into amyloid fibrils in the basal lamina.
  • Myocytes degenerate and die within amyloid deposits, leading to vascular media damage.

Conclusions:

  • Amyloid formation by smooth muscle cells in leptomeningeal vessels follows a secretory pathway.
  • Smooth muscle cells secrete nonfibrillar beta-protein or peptides, which convert to fibrillar beta-amyloid in the basement membrane environment.
  • This mechanism contributes to vascular pathology in Alzheimer's disease.

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