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.
de Vernejoul
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MC
Cellular and Molecular Biology of Bone and Cartilage Department, INSERM U349, Centre Viggo Petersen, Hôpital Lariboisiére, Paris, France.
Cohen-Solal
M
M
Orcel
P
P
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