Spatial Distribution of Bax and Bcl‐2 in Osteocytes After Bone Fatigue: Complementary Roles in Bone Remodeling Regulation?

@article{Verborgt2002SpatialDO,
  title={Spatial Distribution of Bax and Bcl‐2 in Osteocytes After Bone Fatigue: Complementary Roles in Bone Remodeling Regulation?},
  author={Olivier Verborgt and Nadine A. Tatton and Robert J. Majeska and Mitchell B. Schaffler},
  journal={Journal of Bone and Mineral Research},
  year={2002},
  volume={17}
}
Osteocyte apoptosis appears to play a key role in the mechanism by which osteoclastic resorption activity targets bone for removal, because osteocyte apoptosis occurs in highly specific association with microdamage and subsequent remodeling after fatigue. However, beyond terminal deoxynucleotidyl transferase (TdT)‐mediated deoxyuridine triphosphate (dUTP)‐biotin nick end labeling (TUNEL) assay, little is known about the mechanisms controlling osteocyte apoptosis in vivo. In the current studies… 
Activation of resorption in fatigue-loaded bone involves both apoptosis and active pro-osteoclastogenic signaling by distinct osteocyte populations.
TLDR
It is demonstrated that while osteocyte apoptosis triggers the bone remodeling response to microdamage, the neighboring non-apoptotic osteocytes are the major source of pro-osteoclastogenic signals.
Osteocyte Apoptosis Caused by Hindlimb Unloading is Required to Trigger Osteocyte RANKL Production and Subsequent Resorption of Cortical and Trabecular Bone in Mice Femurs
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A STUDY OF OSTEOCYTE APOPTOSIS BY REGION AND QUADRANT IN MURINE CORTICAL BONE
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Osteocytes make up the largest cell population in bone and are believed to be the main mechanosensory bone cells. During mechanical disuse and overuse, osteocyte viability is compromised and is found
Quantitative regional associations between remodeling, modeling, and osteocyte apoptosis and density in rabbit tibial midshafts.
TLDR
It was found that osteocyte density and osteocyte lacunar density did not significantly correlate with modeling or remodeling parameters, suggesting that cell viability should be examined in studies correlating bone turnover parameters with the functional role of osteocytes in bone adaptation.
Evidence for the role of osteocytes in the initiation of targeted remodeling.
TLDR
It was demonstrated that damaged osteocytes locally affect osteoclast precursors by secreting osteoclineogenic factors, and thus can have a role in the initiation of resorption in bone remodelling, which strongly supports the idea that damage to osteocyte cellular network has the potential to stimulate osteoclastic proliferation and therefore the activation of Basic Multicellular Units (BMUs).
Osteocyte apoptosis is mechanically regulated and induces angiogenesis in vitro
TLDR
The results suggest that osteocyte apoptosis is flow‐regulated and promotes angiogenesis in a VEGF‐mediated manner.
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