Exocytotic process as a novel model for mineralization by osteoblasts in vitro and in vivo determined by electron microscopic analysis.

2.50
Hdl Handle:
http://hdl.handle.net/10033/19432
Title:
Exocytotic process as a novel model for mineralization by osteoblasts in vitro and in vivo determined by electron microscopic analysis.
Authors:
Rohde, Manfred ( 0000-0003-0522-3580 ) ; Mayer, H
Abstract:
The process of biomineralization has been examined during osteoblastic differentiation of bone marrow stroma cells (BMSCs) from embryonic chick in culture and in periosteum itself by a number of different techniques including transmission and scanning electron microscopy. In cell culture of BMSCs at days 20-25, crystals were accumulated extracellularly in the collagen matrix, resulting in large plate-like crystallites and noncollagen associated on the culture disk surface. In contrast, up to days 10-18, mainly intracellular mineralization was visible by numerous needle-like crystal structures in the cell cytoplasm and in vacuoles. After 20-30 days, the crystal content of these vacuoles is released, most probably by membrane fusion to the outside of the cells. Energy-dispersive X-ray analysis (EDX), electron spectroscopic imaging, and electron energy loss spectroscopy demonstrated that Ca, O, and P are located in the intra- and extracellular needle-like crystals. From EDX spectra a Ca/P ratio of 1.3 was estimated for the intracellular structures and a Ca/P ratio of 1.5, for the extracellular material (for comparison, the Ca/P ratio in tibiae is 1.6). X-ray diffraction and quantitative infrared spectral analyses also demonstrated an increase of crystalline bone apatite along the mineralization process. In addition to the finding in vitro, the presence of intracellular needle-like crystals in vacuoles could be demonstrated in vivo in osteoblastic cells of the periosteum in tibia of day 11. The results are in favor of a novel model for mineralization by osteoblasts, in which amorphous Ca/P material is directly secreted via an exocytotic process from vacuoles of the osteoblast, deposited extracellularly, propagated into the collagen fibril matrix, and matured to hydroxyapatite.
Affiliation:
Department of Microbial Pathogenesis, Helmholtz Center for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig, Germany. manfred.rohde@helmholtz-hzi.de
Citation:
Exocytotic process as a novel model for mineralization by osteoblasts in vitro and in vivo determined by electron microscopic analysis. 2007, 80 (5):323-36 Calcif. Tissue Int.
Journal:
Calcified tissue international
Issue Date:
May-2007
URI:
http://hdl.handle.net/10033/19432
DOI:
10.1007/s00223-007-9013-5
PubMed ID:
17406769
Type:
Article
Language:
en
ISSN:
0171-967X
Appears in Collections:
Publications of Dept. Medizinische Mikrobiologie (MMIK)

Full metadata record

DC FieldValue Language
dc.contributor.authorRohde, Manfreden
dc.contributor.authorMayer, Hen
dc.date.accessioned2008-02-29T12:42:20Zen
dc.date.available2008-02-29T12:42:20Zen
dc.date.issued2007-05en
dc.identifier.citationExocytotic process as a novel model for mineralization by osteoblasts in vitro and in vivo determined by electron microscopic analysis. 2007, 80 (5):323-36 Calcif. Tissue Int.en
dc.identifier.issn0171-967Xen
dc.identifier.pmid17406769en
dc.identifier.doi10.1007/s00223-007-9013-5en
dc.identifier.urihttp://hdl.handle.net/10033/19432en
dc.description.abstractThe process of biomineralization has been examined during osteoblastic differentiation of bone marrow stroma cells (BMSCs) from embryonic chick in culture and in periosteum itself by a number of different techniques including transmission and scanning electron microscopy. In cell culture of BMSCs at days 20-25, crystals were accumulated extracellularly in the collagen matrix, resulting in large plate-like crystallites and noncollagen associated on the culture disk surface. In contrast, up to days 10-18, mainly intracellular mineralization was visible by numerous needle-like crystal structures in the cell cytoplasm and in vacuoles. After 20-30 days, the crystal content of these vacuoles is released, most probably by membrane fusion to the outside of the cells. Energy-dispersive X-ray analysis (EDX), electron spectroscopic imaging, and electron energy loss spectroscopy demonstrated that Ca, O, and P are located in the intra- and extracellular needle-like crystals. From EDX spectra a Ca/P ratio of 1.3 was estimated for the intracellular structures and a Ca/P ratio of 1.5, for the extracellular material (for comparison, the Ca/P ratio in tibiae is 1.6). X-ray diffraction and quantitative infrared spectral analyses also demonstrated an increase of crystalline bone apatite along the mineralization process. In addition to the finding in vitro, the presence of intracellular needle-like crystals in vacuoles could be demonstrated in vivo in osteoblastic cells of the periosteum in tibia of day 11. The results are in favor of a novel model for mineralization by osteoblasts, in which amorphous Ca/P material is directly secreted via an exocytotic process from vacuoles of the osteoblast, deposited extracellularly, propagated into the collagen fibril matrix, and matured to hydroxyapatite.en
dc.language.isoenen
dc.subject.meshAnimalsen
dc.subject.meshCalcification, Physiologicen
dc.subject.meshCell Differentiationen
dc.subject.meshCells, Cultureden
dc.subject.meshChick Embryoen
dc.subject.meshCollagenen
dc.subject.meshDurapatiteen
dc.subject.meshExocytosisen
dc.subject.meshMicroscopy, Electron, Scanningen
dc.subject.meshMicroscopy, Electron, Transmissionen
dc.subject.meshModels, Biologicalen
dc.subject.meshOsteoblastsen
dc.subject.meshStromal Cellsen
dc.titleExocytotic process as a novel model for mineralization by osteoblasts in vitro and in vivo determined by electron microscopic analysis.en
dc.typeArticleen
dc.contributor.departmentDepartment of Microbial Pathogenesis, Helmholtz Center for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig, Germany. manfred.rohde@helmholtz-hzi.deen
dc.identifier.journalCalcified tissue internationalen

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