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The Formation of Calcified Nanospherites during Micropetrosis Represents a Unique Mineralization Mechanism in Aged Human Bone |
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| Authors: | Petar Milovanovic Elizabeth A Zimmermann Annika vom Scheidt Björn Hoffmann George Sarau Timur Yorgan Michaela Schweizer Michael Amling Silke Christiansen Björn Busse |
| Affiliation: | 1. Institute for Osteology and Biomechanics, University Medical Center Hamburg‐Eppendorf, Hamburg, Germany;2. Laboratory for Anthropology, Institute of Anatomy, Faculty of Medicine, University of Belgrade, Belgrade, Serbia;3. Christiansen Research Group, Max Planck Institute for the Science of Light, Erlangen, Germany;4. Institute of Optics, Information and Photonics, Friedrich‐Alexander‐Universit?t Erlangen‐Nürnberg (FAU), Erlangen, Germany;5. Center of Molecular Neurobiology, University Medical Center Hamburg‐Eppendorf, Hamburg, Germany;6. Institute of Nano‐architectures for Energy Conversion, Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany;7. Physics Department, Freie Universit?t Berlin, Berlin, Germany;8. Materials Sciences Division, Lawrence Berkeley National Laboratory/University of California‐Berkeley, CA, USA |
| Abstract: | Osteocytes—the central regulators of bone remodeling—are enclosed in a network of microcavities (lacunae) and nanocanals (canaliculi) pervading the mineralized bone. In a hitherto obscure process related to aging and disease, local plugs in the lacuno‐canalicular network disrupt cellular communication and impede bone homeostasis. By utilizing a suite of high‐resolution imaging and physics‐based techniques, it is shown here that the local plugs develop by accumulation and fusion of calcified nanospherites in lacunae and canaliculi (micropetrosis). Two distinctive nanospherites phenotypes are found to originate from different osteocytic elements. A substantial deviation in the spherites' composition in comparison to mineralized bone further suggests a mineralization process unlike regular bone mineralization. Clearly, mineralization of osteocyte lacunae qualifies as a strong marker for degrading bone material quality in skeletal aging. The understanding of micropetrosis may guide future therapeutics toward preserving osteocyte viability to maintain mechanical competence and fracture resistance of bone in elderly individuals. |
| Keywords: | biomineralization bone cells lacuno‐canalicular network nanospherites osteocytes |