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Matrix vesicles mediate mineralization of human thyroid cartilage
1Department of Anatomy and Histology, School of Dental Medicine, University of Pennsylvania, Philadelphia 19104, USA.
Calcified Tissue International
|April 1, 2000
Summary
The study identifies matrix vesicles as key initiators of human thyroid cartilage mineralization. These vesicles contain essential components like alkaline phosphatase and annexins, facilitating calcium and phosphate deposition.
Area of Science:
- Biochemistry
- Histology
- Biomineralization
Background:
- Thyroid cartilage mineralization and ossification mechanisms remain poorly understood.
- This process begins post-adolescence, after skeletal ossification and epiphyseal plate closure.
Purpose of the Study:
- To investigate the mechanisms of human thyroid cartilage mineralization.
- To identify the cellular and molecular components involved in this process.
Main Methods:
- Ultrastructural analysis of human thyroid cartilage.
- Isolation of matrix vesicles via enzymatic digestion and ultracentrifugation.
- Biochemical and immunoblot analyses of isolated matrix vesicles.
Main Results:
- Mineralization initiates near cartilage canals, associated with asbestoid collagen fibers.
- Matrix vesicles, containing Ca2+-Pi complexes, alkaline phosphatase, annexins II, V, VI, and collagens II and X, were isolated.
- These vesicles are implicated in initiating and mediating calcium-phosphate deposition.
Conclusions:
- Isolated matrix vesicles from human thyroid cartilage possess all necessary components for initiating mineralization.
- Annexins and collagen interactions within matrix vesicles facilitate calcium influx and crystal formation.
- Matrix vesicles are central to the biomineralization of human thyroid cartilage.