Bone cytokines.
Cytokines and growth factors are important in bone tissue as mediators of cell-to-cell and matrix-to-cell communication. Cytokines also locally mediate the effects of several hormones on bone cells. Indeed, calciotropic hormones modulate the bone-cell production rate of these factors and, conversely, can change the number of receptors for these hormones on bone cells. Most cytokines are active in bone, but the existence of a bone-specific cytokine is still questioned. Recent work has searched for estradiol modulation of osteoblastic cytokine acting on osteoclast differentiation. In mice, increased interleukin-6 production by osteoblasts is responsible for increased bone resorption occurring after ovariectomy. Interleukin-6 could also be an autocrine or paracrine factor in the pathogenesis of increased resorption occurring in giant cell tumor or in Paget's disease. During osteoporosis and age-related bone changes, modifications of the production of insulin-like growth factor I or of one of its binding proteins could be responsible for low bone formation. Interrelationships between cytokines and hormones can affect the action of parathyroid hormone-related peptide on bone cells. The field of implication of cytokines in metabolic bone disease is growing.
Cellular and Molecular Biology of Bone and Cartilage Department, INSERM U349, Centre Viggo Petersen, Hôpital Lariboisiére, Paris, France.
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de Vernejoul
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Cohen-Solal
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Orcel
D000375:Aging / Q000097:blood; D001846:Bone Development; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism* / Q000502:physiology; D004958:Estradiol / Q000494:pharmacology; D006801:Humans; D009000:Monocytes / Q000378:metabolism; D010010:Osteoclasts / Q000378:metabolism; D010024:Osteoporosis / Q000097:blood; D010281:Parathyroid Hormone / Q000502:physiology; D013002:Somatomedins / Q000032:analysis
D016207:Cytokines; D010281:Parathyroid Hormone; D013002:Somatomedins; D004958:Estradiol