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Calcified Tissue International

, Volume 94, Issue 1, pp 5–24 | Cite as

Osteocytes: Master Orchestrators of Bone

  • Mitchell B. Schaffler
  • Wing-Yee Cheung
  • Robert Majeska
  • Oran Kennedy
Review

Abstract

Osteocytes comprise the overwhelming majority of cells in bone and are its only true “permanent” resident cell population. In recent years, conceptual and technological advances on many fronts have helped to clarify the role osteocytes play in skeletal metabolism and the mechanisms they use to perform them. The osteocyte is now recognized as a major orchestrator of skeletal activity, capable of sensing and integrating mechanical and chemical signals from their environment to regulate both bone formation and resorption. Recent studies have established that the mechanisms osteocytes use to sense stimuli and regulate effector cells (e.g., osteoblasts and osteoclasts) are directly coupled to the environment they inhabit—entombed within the mineralized matrix of bone and connected to each other in multicellular networks. Communication within these networks is both direct (via cell–cell contacts at gap junctions) and indirect (via paracrine signaling by secreted signals). Moreover, the movement of paracrine signals is dependent on the movement of both solutes and fluid through the space immediately surrounding the osteocytes (i.e., the lacunar–canalicular system). Finally, recent studies have also shown that the regulatory capabilities of osteocytes extend beyond bone to include a role in the endocrine control of systemic phosphate metabolism. This review will discuss how a highly productive combination of experimental and theoretical approaches has managed to unearth these unique features of osteocytes and bring to light novel insights into the regulatory mechanisms operating in bone.

Keywords

Osteocyte Biomechanics Mechanotransduction Intercellular communication 

Notes

Acknowledgments

This study was supported by Grants AR41210, AR57139, and AR60445 from the National Institute of Arthritis, Musculoskeletal and Skin Diseases.

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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Mitchell B. Schaffler
    • 1
  • Wing-Yee Cheung
    • 1
  • Robert Majeska
    • 1
  • Oran Kennedy
    • 2
  1. 1.Department of Biomedical EngineeringCity College of New YorkNew YorkUSA
  2. 2.Department of Orthopaedic SurgeryNew York UniversityNew YorkUSA

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