Morphology and ultrastructure of osteoid-osteocytes were studied in serial thin sections (700–800 Å thick) of periosteal woven bone in tibiae of 15-day-old chick embryos. The three-dimensional shapes of 21 partially, and of one fully sectioned cell were reconstructed manually and by means of a computer-assisted image analyser.
Osteoid-osteocytes are active cells engaged in organic matrix secretion and calcification. Like osteoblasts, their activity seems to be polarized towards the mineralization front, as shown by the presence of cytoplasmic processes on their mineral-facing side and by the position of the nucleus toward the vascular side of the cytoplasm. Cellular processes directed towards blood vessels appear only at a later stage, i.e. when the mineralization starts to spread all round the cell.
The asynchrony in formation, together with the observed differences in morphology suggest the hypothesis that the cellular processes of the mineral-facing side are mainly involved in bone formation and those of the vascular side in cell nutrition.
|2009||McNamara LM, Majeska RJ, Weinbaum S, Friedrich V, Schaffler MB. Attachment of osteocyte cell processes to the bone matrix. Anat Rec. March 2009;292(3):355-363.|
|2004||You L, Weinbaum S, Cowin SC, Schaffler MB. Ultrastructure of the osteocyte process and its pericellular matrix. Anat Rec. June 2004;278A(2):505-513.|
|1990||Palumbo C, Palazzini S, Marotti G. Morphological study of intercellular junctions during osteocyte differentiation. Bone. 1990;11(6):401-406.|
|2001||Kamioka H, Honjo T, Takano-Yamamoto T. A three-dimensional distribution of osteocyte processes revealed by the combination of confocal laser scanning microscopy and differential interference contrast microscopy. Bone. February 2001;28(2):145-149.|
|1993||Marotti G. A new theory of bone lamellation. Calcif Tiss Int. February 1993;53(suppl 1):S47-S56.|
|2014||Schaffler MB, Cheung W-Y, Majeska R, Kennedy O. Osteocytes: master orchestrators of bone. Calcif Tiss Int. January 2014;94(1):5-24.|
|2006||Franz-Odendaal TA, Hall BK, Witten PE. Buried alive: how osteoblasts become osteocytes. Dev Dyn. January 2006;235(1):176-190.|
|2013||Dallas SL, Prideaux M, Bonewald LF. The osteocyte: an endocrine cell … and more. Endocr Rev. October 2013;34(4):658-690.|
|2004||Knothe Tate ML, Adamson JR, Tami AE, Bauer TW. The osteocyte. Int J Biochem Cell Biol. January 2004;36(1):1-8.|
|1990||Marotti G, Cane V, Palazzini S, Palumbo C. Structure-function relationships in the osteocyte. Ital J Min Electrol Metabol. 1990;4(2):93-106.|
|1994||Weinbaum S, Cowin SC, Zeng Y. A model for the excitation of osteocytes by mechanical loading-induced bone fluid shear stresses. J Biomech. March 1994;27(3):339-360.|
|1995||Cowin SC, Weinbaum S, Zeng Y. A case for bone canaliculi as the anatomical site of strain generated potentials. J Biomech. November 1995;28(11):1281-1297.|
|1991||Cowin SC, Moss-Salentijn L, Moss ML. Candidates for the mechanosensory system in bone. J Biomech Eng. May 1991;113(2):191-197.|
|1994||Aarden EM, Burger EH, Nijweide PJ. Function of osteocytes in bone. J Cell Biochem. July 1994;55(3):287-299.|
|2021||Palumbo C, Ferretti M. The osteocyte: from "prisoner" to "orchestrator". J Funct Morphol Kinesiol. 2021;6(1):28.|
|2015||Scully N. Differentiation of Osteoblasts to Osteocytes in 3D Type I Collagen Gels: A Novel Tool to Study Osteocyte Responses to Mechanical Loading [PhD thesis]. Cardiff, UK: Cardiff University; April 2015.|
|2002||You L. A New View of Mechanotransduction in Bone Cells [PhD thesis]. New York, NY: The City University of New York; 2002.|
|2005||Beno T. Investigating the Role of Microstructure in Bone Permeability [PhD thesis]. New York, NY: The City University of New York; 2005.|
|2019||Ilas DC. The Role of Mesenchymal Stem Cells and Osteocytes in Subchondral Bone Changes in Hip Osteoarthritis [PhD thesis]. University of Leeds; May 2019.|
|2007||Malone AMD. Mechanotransduction Mechanisms in Bone Cells [PhD thesis]. Stanford University; August 2007.|