The cast of clasts: catabolism and vascular invasion during bone growth, repair, and disease by osteoclasts, chondroclasts, and septoclasts

摘要: Three named cell types degrade and remove skeletal tissues during growth, repair, or disease: osteoclasts, chondroclasts, septoclasts. A fourth type, unnamed less understood, removes nonmineralized cartilage development of secondary ossification centers. "Osteoclasts," best known studied, are polykaryons formed by fusion monocyte precursors under the influence colony stimulating factor 1 (CSF)-1 (M-CSF) RANKL. They resorb bone remodeling, disease. "Chondroclasts," originally described as highly similar in cytological detail to reside on mineralized cartilage. may be identical osteoclasts since date there no distinguishing markers for them. Because also consume cores along with term "chondroclast" might reserved cells attached only "Septoclasts" studied appreciated. mononuclear perivascular rich cathepsin B. extend a cytoplasmic projection ruffled membrane last transverse septum hypertrophic growth plate, permitting capillaries bud into it. To do this, antiangiogenic signals must give way vascular trophic factors, mainly endothelial (VEGF). The final type excavates canals invasion articular "clasts" considered context fracture repair diseases such arthritis tumor metastasis. Many observations support an essential role chondrocytes recruiting septoclasts osteoclasts/chondroclasts supplying VEGF intimate relationship between blood vessels turnover is examined.