Mohan S, Baylink D J
Department of Medicine, Loma Linda University, CA.
Clin Orthop Relat Res. 1991 Feb(263):30-48.
Bone volume is determined by the relative rates of bone formation and bone resorption. Recent research in several laboratories suggests that growth factors may act locally to modulate bone formation by stimulating osteoblast proliferation and activity. A number of bone-derived growth factors have been isolated and characterized from bone matrix extracts and from media conditioned by bone cells and bone organs in culture. The growth factors found in bone matrix include insulinlike growth factors I and II, transforming growth factor-beta, acidic and basic fibroblast growth factor, platelet-derived growth factor, and bone morphogenetic proteins. Conditioned medium from bone cells contains several of these growth factors and also hematopoietic factors. These bone matrix-derived growth factors have different biologic activities, including mitogenic, differentiating, chemotactic, and osteolytic activities. Evidence suggests that bone cells produce substantial quantities of growth factors for extracellular storage in bone matrix. Apart from being produced for extracellular storage, it is possible that growth factors secreted by bone cells have acute effects on their neighboring osteoblastic cells, i.e., paracrine action, or on themselves, i.e., autocrine action. The release of matrix-stored growth factors by bone resorption may mean that growth factors act as delayed paracrine agents, e.g., osteoblasts deposit growth factors in bone and later when these growth factors are released from bone via bone resorption, the growth factors stimulate osteoblast precursors to proliferate. The findings that bone is a storehouse for growth factors and that bone cells in culture produce and respond to bone growth factors suggest bone growth factors may act as potential determinants of local bone formation. This review is focused on the structure, regulation, and biologic actions of the known bone growth factors.
骨体积由骨形成和骨吸收的相对速率决定。多个实验室最近的研究表明，生长因子可能通过刺激成骨细胞增殖和活性在局部调节骨形成。已从骨基质提取物以及培养的骨细胞和骨器官所产生的培养基中分离并鉴定出多种骨源性生长因子。在骨基质中发现的生长因子包括胰岛素样生长因子I和II、转化生长因子-β、酸性和碱性成纤维细胞生长因子、血小板衍生生长因子以及骨形态发生蛋白。来自骨细胞的条件培养基含有这些生长因子中的几种以及造血因子。这些骨基质衍生的生长因子具有不同的生物学活性，包括促有丝分裂、分化、趋化和溶骨活性。有证据表明，骨细胞产生大量生长因子以在骨基质中进行细胞外储存。除了为细胞外储存而产生外，骨细胞分泌的生长因子可能对其相邻的成骨细胞有急性作用，即旁分泌作用，或对其自身有作用，即自分泌作用。通过骨吸收释放基质储存的生长因子可能意味着生长因子作为延迟的旁分泌因子起作用，例如，成骨细胞将生长因子沉积在骨中，随后当这些生长因子通过骨吸收从骨中释放出来时，它们刺激成骨细胞前体增殖。骨是生长因子的储存库以及培养的骨细胞产生并对骨生长因子作出反应的这些发现表明，骨生长因子可能是局部骨形成的潜在决定因素。本综述聚焦于已知骨生长因子的结构、调节和生物学作用。
