Summary
Implantation of mineral-containing bone fragments into calvarial defects in rats initiates a rapid and reproducible resorption of the bone matrix. After 7 days, a dense tissue develops with mononucleated as well as multinucleated cells surrounding and between the bone fragments. Electron microscopy revealed that these cells belong to the mononuclear phagocytic system; they were identified as macrophages, epithelioid cells, foreign body giant cells, and Langerhans cells. In addition to the common ultrastructural characteristics, these cells had electron-dense, focal specializations along their cell membrane with a coating on the exterior, corresponding to subplasmalemmal linear densities. Small, unidentified cells with electron-dense ground cytoplasm were often seen in close proximity to more differentiated cells. No halisteresis had occurred on the surfaces of the bone fragments. Indentations resembling Howship's lacunae were frequent; these contained mononucleated as well as multinucleated cells. Some surfaces were frayed and collagen fibers were exposed, but the cells apposed to these surfaces did not have ruffled borders as are seen in osteoclasts. Some bone fragments were broken up and cell processes had penetrated deep into the cracks, separating pieces of matrix. Small matrix particles were phagocytosed by macrophages, but not by epithelioid cells or giant cells. It appears that enzymes capable of degrading bone matrix components were secreted by the more differentiated cells of the mononuclear phagocytic system. They eroded the bone surface in a way reminiscent of osteoclastic bone resorption. They also entered the canaliculi to act from within the bone fragment, a process possible only in dead bone. We suggest a possible relationship of these cells with osteoclasts.
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Mundy GR, Altman AJ, Gondek MD, Bandelin JG (1977) Direct resorption of bone by human monocytes. Science 196:1109–1111
Kahn AJ, Stewart CC, Teitelbaum SL (1978) Contact-mediated bone resorption by human monocytes in vitro. Science 199:988–990
Teitelbaum SL, Stewart CC, Kahn AJ (1979) Rodent peritoneal macrophages as bone resorbing cells. Calcif Tissue Int 27:255–261
Walker DG (1975) Control of bone resorption by hematopoietic tissue: The induction and reversal of congenital osteopetrosis in mice through use of bone marrow and splenic transplants. J Exp. Med 142:651–663
Owen M (1978) Histogenesis of bone cells. Calcif Tissue Res 25:205–207
Ash P, Loutit JF, Townsend KMS (1980) Osteoclasts derived from haematopoietic stem cells. Nature 283:669–670
Heersche JNM (1978) Mechanism of osteoclastic bone resorption: A new hypothesis. Calcif Tissue Res 26:81–84
Glowacki J, Altobelli D, Mulliken JB (1981) Fate of mineralized and demineralized osseous implants in cranial defects. Calcif Tissue Int 33:71–76
Holtrop ME, Raisz LG, Simmons HA (1974) The effect of parathyroid hormone, colchicine and calcitonin on the ultrastructure and the activity of osteoclasts in organ culture. J Cell Biol 60:346–355
Sutton JS, Weiss L (1966) Transformation of monocytes in tissue culture into macrophages, epithelioid cells, and multinucleated giant cells: An electron microscope study. J Cell Biol 28:303–332
Fedorko M, Hirsch JG (1970) Structure of monocytes and macrophages. Semin Hematol 7:109–124
Adams DO (1974) The structure of mononuclear phagocytes differentiatingin vivo. I. Sequential fine and histologic studies of the effect of Bacillus Calmette-Guerin (BCG). Am J Pathol 76:17–48
Papadimitriou JM, Spector WG (1971) The origin, properties and fate of epithelioid cells. J Pathol 105:187–203
Spector WG, Mariano M (1973) Macrophage behaviour in experimental granulomas. In R. van Furth (ed): Mononuclear Phagocytes in Immunity, Infection, and Pathology. Blackwell Scientific, Oxford, pp 927–938
Mariano M, Spector WG (1974) The formation and properties of macrophage polykaryons (inflammatory giant cells). J Pathol 113:1–19
Spector WG (1975) The dynamics of granulomas and the significance of epithelioid cells. Pathol Biol 23:437–439
Yoneda T, Mundy GR (1979) Monocytes regulate osteoclast-activating factor production by releasing prostaglandins. J Exp Med 150:338–350
Kawanami O, Ferrans VJ, Crystal RG (1980) Subplasmalemmal linear densities in cells of the mononuclear phagocyte system in lung. Am J Pathol 100:131–150
Rifkin BR, Baker RL, Coleman SJ (1979) An ultrastructural study of macrophage-mediated resorption of calcified tissue. Cell Tissue Res 202:125–132
Nathan CF, Murray HW, Cohn ZA (1980) The macrophage as an effector cell. N Engl J Med 303:622–626
Werb Z, Gordon S (1975) Secretion of a specific collagenase by stimulated macrophages. J Exp Med 142:346–360
Werb Z, Banda MJ, Jones PA (1980) Degradation of connective tissue matrices by macrophages. I. Proteolysis of elastin, glycoproteins, and collagen by proteinases isolated from macrophages. J Exp Med 152:1340–1457
Mundy GR, Varani J, Orr W, Gondek MD, Ward PA (1978) Resorbing bone is chemotactic for monocytes. Nature 275:132–135
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Holtrop, M.E., Cox, K.A. & Glowacki, J. Cells of the mononuclear phagocytic system resorb implanted bone matrix: A histologic and ultrastructural study. Calcif Tissue Int 34, 488–494 (1982). https://doi.org/10.1007/BF02411290
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DOI: https://doi.org/10.1007/BF02411290