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Physiochemical characterization of cardiovascular calcified deposits. I. Isolation, purification and instrumental
B B Tomazic1, W E Brown, L A Queral
1Paffenbarger Research Center, American Dental Association Health Foundation, National Bureau of Standards, Gaithersburg, MD 20899.
Insights
Pathologic cardiovascular deposits, including atherosclerotic and bioprosthetic ones, share similar chemical structures. These mineral deposits are primarily carbonate-substituted apatite, differing from hydroxyapatite.
Area of Science:
- Biomaterials Science
- Cardiovascular Research
- Materials Chemistry
Background:
- Cardiovascular diseases involve pathological mineral deposits on host surfaces.
- Bioprosthetic devices can also accumulate mineral deposits.
- Understanding these deposits is crucial for improving cardiovascular health and device longevity.
Purpose of the Study:
- To compare the physicochemical properties of calcified human aortic atherosclerotic deposits and calf ventricular assist device (CVAD) bioprosthetic deposits.
- To identify compositional and structural similarities between these two types of pathological mineral deposits.
- To elucidate the formation mechanism of cardiovascular deposits.
Main Methods:
- Isolation and deproteination of pathological deposits using hydrazine treatment.
- Comprehensive chemical and instrumental analyses (e.g., X-ray diffraction, spectroscopy) for detailed characterization.
- Morphological and structural evaluation of the microcrystalline deposit materials.
Main Results:
- Both atherosclerotic and CVAD deposits are morphologically heterogeneous microcrystalline materials.
- Chemically, these deposits can be classified as carbonate-substituted apatite.
- The identified apatite composition exhibits properties distinct from pure hydroxyapatite.
- Evidence suggests octacalcium phosphate hydrolysis as a precursor in the formation mechanism.
Conclusions:
- Cardiovascular mineral deposits, regardless of their origin (atherosclerotic or bioprosthetic), share fundamental chemical and structural similarities.
- The composition is primarily carbonate-substituted apatite, not simple hydroxyapatite.
- The formation mechanism likely involves octacalcium phosphate, providing insights into calcification processes.
Abstract:
Calcified human aortic atherosclerotic deposits and calf ventricular assist device bioprosthetic deposits were isolated and deproteinated by hydrazine treatment. Detailed chemical and instrumental analyses were applied to gain comprehensive physicochemical information which makes possible establishing compositional and structural similarities between the 2 types of pathologic mineral deposits which form on different host surfaces. These microcrystalline deposit materials are morphologically very heterogeneous and can be represented chemically as carbonate substituted apatite which, in some of its properties, significantly differs from hydroxyapatite. It is indicated that the mechanism for the formation of cardiovascular deposits proceeds through hydrolysis of octacalcium phosphate precursor.