The Ultrastructure of the Osteoclast and its Functional Implications

  title={The Ultrastructure of the Osteoclast and its Functional Implications},
  author={Marijke E. Holtrop and Gregory J. King},
  journal={Clinical Orthopaedics and Related Research},
Recent findings on the ultrastructure of the osteoclast indicate that special attention should be given to the ruffled border, clear zone, and the vacuoles and vesicles of the cell and their significance for the mechanism of breakdown of bone matrix. The ruffled border is seen as an extensive area of cell surface where secretion of enzymes as well as uptake of matrix components takes place. The clear zone encircles the ruffled border completely and thus forms an integral part of the resorbing… Expand
New knowledge on the origin, function and fate of osteoclasts.
  • E. Bonucci
  • Medicine
  • Clinical orthopaedics and related research
  • 1981
Osteoclast nuclei are continuously incorporated and shed, so that individual cells are continuously renewed, which makes the life-span of the osteoclast extremely difficult to determine. Expand
Osteoclasts: structure and function.
Scanning electron microscopy not only demonstrated the surface appearance of osteoclasts, and their predilection for spreading on various substratum components, but has also been used as an adjunct in resorption assays in which areas of Resorption lacunae are measured as indicators of cell activity. Expand
The main determinants of the biology of the osteoclast are first its attachment to the bone matrix, leading to the formation of the sealed-off bone resorbing compartment and, second, the polarized acidification of, and secretion of enzymes into, this compartment. Expand
Cytoskeletal changes in osteoclasts during the resorption cycle.
Osteoclasts are large, multinucleated cells which change their shape and polarity according to their resorptive activity. At least in vitro, nonresorbing osteoclasts move on the bone surface and doExpand
A new specialized cell-matrix interaction in actively resorbing osteoclasts.
The results indicate that the net concentration of secreted and resorbed components is a balance between generation rate and limited diffusion rather than the presence of an impermeable barrier as previously suggested. Expand
Distinctive Subdomains in the Resorbing Surface of Osteoclasts
The chloride/proton antiporter ClC-7 might serve not only to provide the counter-ions that enable proton pumping, but also to facilitate resorption by acting as a ‘functional sealing zone’. Expand
Histochemical Studies of Lysosomal Forming System in Osteoclasts with Calcitonin Treatment: Acid Phosphatase and Glucose-6-Phosphatase
To evaluate whether calcitonin influences the lysosomal forming system in osteoclasts, acid phosphatase (ACPase) and glucose-6-phosphatase (G6Pase) were examined in cells with and without hormonalExpand
Effects of the proteinase inhibitors leupeptin and E-64 on osteoclastic bone resorption
The in vitro effects of leupeptin and E-64 in certain respects resemble ultrastructural features of pycnodysostosis, an osteopetrosislike bone disorder, in line with the hypothesis that this disease is caused by insufficient activity of osteoclastic cysteine-proteinases. Expand
Intracellular membrane trafficking in bone resorbing osteoclasts
Details of specific membrane transport processes in the osteoclasts, e.g., the formation of the sealing zone and transcytosis of bone degradation products from the resorption lacuna to the functional secretory domain remain to be clarified. Expand
The distribution of podosomes in osteoclasts cultured on bone laminae: Effect of retinol
A comparative transmission electron microscopy study of osteoclasts adhering on bone laminae in vitro or in vivo indicates that podosomes with identical features are present in the clear zone of the osteoclast in either condition. Expand