TY - JOUR
T1 - Osteocyte-directed bone demineralization along canaliculi
AU - Nango, Nobuhito
AU - Kubota, Shogo
AU - Hasegawa, Tomoka
AU - Yashiro, Wataru
AU - Momose, Atsushi
AU - Matsuo, Koichi
N1 - Funding Information:
We thank Akihisa Takeuchi, Yoshio Suzuki and Naoto Yagi at the Japan Synchrotron Radiation Research Institute (JASRI/SPring-8) for help with synchrotron X-ray microscopy, and Elise Lamar for critical reading of the manuscript. This work was supported by JSPS KAKENHI Grant Numbers 25293327 and 26670674 to KM, and 19350027 to AM, and in part by the Network Joint Research Center for Materials and Devices. Experiments were performed with approval of the SPring-8 committee (Proposal No. 2009A1195, 2009A1871, 2010B1438, 2012B1316, 2013B1213, 2013B1425).
Publisher Copyright:
© 2015 The Authors.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2016/3/1
Y1 - 2016/3/1
N2 - The mammalian skeleton stores calcium and phosphate ions in bone matrix. Osteocytes in osteocyte lacunae extend numerous dendrites into canaliculi less than a micron in diameter and which are distributed throughout bone matrix. Although osteoclasts are the primary bone-resorbing cells, osteocytes also reportedly dissolve hydroxyapatite at peri-lacunar bone matrix. However, robust three-dimensional evidence for peri-canalicular bone mineral dissolution has been lacking. Here we applied a previously reported Talbot-defocus multiscan tomography method for synchrotron X-ray microscopy and analyzed the degree of bone mineralization in mouse cortical bone around the lacuno-canalicular network, which is connected both to blood vessels and the peri- and endosteum. We detected cylindrical low mineral density regions spreading around canaliculi derived from a subset of osteocytes. Transmission electron microscopy revealed both intact and demineralized bone matrix around the canaliculus. Peri-canalicular low mineral density regions were also observed in osteopetrotic mice lacking osteoclasts, indicating that osteoclasts are dispensable for peri-canalicular demineralization. These data suggest demineralization can occur from within bone through the canalicular system, and that peri-canalicular demineralization occurs not uniformly but directed by individual osteocytes. Blockade of peri-canalicular demineralization may be a therapeutic strategy to increase bone mass and quality.
AB - The mammalian skeleton stores calcium and phosphate ions in bone matrix. Osteocytes in osteocyte lacunae extend numerous dendrites into canaliculi less than a micron in diameter and which are distributed throughout bone matrix. Although osteoclasts are the primary bone-resorbing cells, osteocytes also reportedly dissolve hydroxyapatite at peri-lacunar bone matrix. However, robust three-dimensional evidence for peri-canalicular bone mineral dissolution has been lacking. Here we applied a previously reported Talbot-defocus multiscan tomography method for synchrotron X-ray microscopy and analyzed the degree of bone mineralization in mouse cortical bone around the lacuno-canalicular network, which is connected both to blood vessels and the peri- and endosteum. We detected cylindrical low mineral density regions spreading around canaliculi derived from a subset of osteocytes. Transmission electron microscopy revealed both intact and demineralized bone matrix around the canaliculus. Peri-canalicular low mineral density regions were also observed in osteopetrotic mice lacking osteoclasts, indicating that osteoclasts are dispensable for peri-canalicular demineralization. These data suggest demineralization can occur from within bone through the canalicular system, and that peri-canalicular demineralization occurs not uniformly but directed by individual osteocytes. Blockade of peri-canalicular demineralization may be a therapeutic strategy to increase bone mass and quality.
KW - Demineralization/remineralization
KW - Mineral metabolism
KW - Osteocyte canaliculus
KW - Osteocytic osteolysis
KW - Synchrotron radiation
KW - Talbot-defocus multiscan tomography
UR - http://www.scopus.com/inward/record.url?scp=84955474709&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84955474709&partnerID=8YFLogxK
U2 - 10.1016/j.bone.2015.12.006
DO - 10.1016/j.bone.2015.12.006
M3 - Article
C2 - 26709236
AN - SCOPUS:84955474709
SN - 8756-3282
VL - 84
SP - 279
EP - 288
JO - Bone
JF - Bone
ER -
