Related Experiment Videos
Ultrastructure and composition of asteroid bodies
1Department of Ophthalmology, Medical University of Lübeck, Germany. jorgw@yahoo.com
Investigative Ophthalmology & Visual Science
|March 29, 2001
Summary
Asteroid bodies in the vitreous are composed of hydroxyapatite, similar to bone mineral. Glycosaminoglycans regulate the biomineralization process in this eye condition.
Area of Science:
- Ophthalmology
- Biochemistry
- Materials Science
Background:
- Asteroid hyalosis is characterized by asteroid bodies in the vitreous.
- The composition and formation of asteroid bodies are not fully understood.
Purpose of the Study:
- Investigate the ultrastructure of asteroid bodies.
- Identify inorganic and organic components of asteroid bodies.
Main Methods:
- Electron energy loss spectroscopy and transmission electron microscopy for elemental analysis.
- Lectin and antibody conjugates for glycosaminoglycan localization.
- Cationic colloidal gold for detecting anionic sites.
- Fast Fourier transform analysis for ultrastructural details.
Main Results:
- Asteroid bodies show homogeneous distribution of calcium, phosphorus, and oxygen, similar to hydroxyapatite.
- Chondroitin-6-sulfate is present at the periphery, and hyaluronic acid in the inner matrix.
- Ultrastructure reveals 7-nm periodicity lamellar stacks.
Conclusions:
- Asteroid bodies share structural and elemental similarities with hydroxyapatite.
- Proteoglycans and glycosaminoglycans regulate the biomineralization process in asteroid hyalosis.