Peritubular dentin, a vertebrate apatitic mineralized tissue without collagen: role of a phospholipid-proteolipid complex
| Autor: | Arthur Veis, Bat Ami Gotliv |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Endocrinology
Diabetes and Metabolism Proteolipids Molecular Sequence Data Phospholipid Spectrometry Mass Secondary Ion Apatite Glycosaminoglycan chemistry.chemical_compound Endocrinology stomatognathic system Phosphatidylcholine Dentin medicine Animals Orthopedics and Sports Medicine Amino Acid Sequence Phospholipids Phosphatidylserine stomatognathic diseases Tubule Odontoblast medicine.anatomical_structure Biochemistry chemistry visual_art Biophysics visual_art.visual_art_medium Microscopy Electron Scanning Cattle Electrophoresis Polyacrylamide Gel Chromatography Thin Layer |
| Zdroj: | Calcified tissue international. 81(3) |
| ISSN: | 0171-967X |
| Popis: | Peritubular dentin (PTD), a highly mineralized annular ring surrounding each odontoblastic process within the dentin, is an enigmatic component in vertebrate teeth. To characterize its structure and composition, we have coupled in situ scanning electron microscopic (SEM) and time-of-flight secondary ion mass spectrometric (TOF-SIMS) analysis of the surface composition of intact bovine coronal dentin with the isolation of intact PTD from hypochlorite-treated dentin and its subsequent TOF-SIMS and direct chemical analysis. The isolated PTD is shown to be a mineralized but porous structure complexed with a high-molecular mass calcium-proteolipid-phospholipid-phosphate complex, which cannot be extracted from the dentin prior to demineralization. The TOF-SIMS and direct amino acid analysis data confirm that the PTD protein is rich in glutamic acid but does not contain collagen. Phosphatidylcholine, phosphatidylserine, and phosphatidylinositol are present, along with a mannose-rich glycan and chondroitin-4- and chondroitin-6-sulfate glycosaminoglycans. PTD apatite, well described in the literature, must therefore form in this noncollagenous proteolipid-phospholipid complex without the intervention of collagen; nevertheless, as shown by SEM, the apatite is formed in small platy crystals, as in the bulk of the intertubular dentin (ITD). We hypothesize that the porous nature of the PTD and its proteolipid-phospholipid complexes may be involved in regulating communication between the ITD and internal PTD tubule fluids and the odontoblasts, similar to the involvement of such lipid complexes in neural, brain, and nuclear transport functions. Thus, the PTD should not be considered solely as a passive structural element in some teeth but as part of the system that allows for the vital function of the dentin. |
| Databáze: | OpenAIRE |
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