July 29, 2012
BMP, bFGF, has long been studies have shown that bone formation in two very important cytokines. BMP has long been proved to have a strong osteoinductive capacity. From bone cells themselves synthesized bFGF in an autocrine or paracrine in the bone matrix, combining bFGF and osteoblast-like cell surface receptor can promote its conversion to osteogenic cells. In vitro experiments confirmed that of bFGF can directly stimulate rat calvaria bone cells increased DNA synthesis, thereby increasing the number of osteoblasts the synthesis of collagen. Recently, studies have found that BMP, bFGF, and VEGF secretion and expression of the existence of a very close relationship. This experiment on the basis of the results of previous studies, observation of VEGF, respectively, in the application of rhBMP-2 expression and distribution of bFGF stimulation of bone marrow stromal cells, and the corresponding performance for osteogenesis do a comparison and found that in vitro application of rhBMP-2 and bFGF can indeed promote the expression of important mediators of VEGF to promote vascular endothelial cell proliferation, while increasing osteoblast performance. The joint application of these two cytokines can not only accelerate the bone marrow stromal cell proliferation and promote cell conversion to osteoblasts direction, so as to achieve better osteogenesis. First of bFGF to promote the proliferation of bone marrow stromal cells and then apply to promote the expression of osteogenic phenotype rhBMP-2, then the effect on the proliferation of bFGF and rhBMP-2 to promote differentiation are unaffected, which can play two cytokines in maximum biological effectiveness.
VEGF is a multifunctional cytokine secreted by platelets, megakaryocytes, endothelial cells and osteoblasts, and its role throughout human reproduction, development, tissue regeneration, repair, and tumor pathophysiological process. Many recent studies have shown that also play an important role of VEGF in bone formation and repair, the expression level directly affect the future into the bone's blood supply, affect the speed and quality of the osteoblast.
VEGF was the introduction of bone tissue engineering technology is bound to promote new bone formation, increase the speed and quality of new bone. Exogenous VEGF in vivo half-life is short, and expensive, its application bring great inconvenience. Bone marrow stromal cells is a commonly used seed cells for bone tissue engineering, it contains many cells such as endothelial cells into fiber cells, macrophages, etc. can be secreted expression of VEGF in. How to stimulate the bone marrow stromal cells to promote the secretion of VEGF is another important means of expression of VEGF
In the early stage of fracture, soft tissue defects, systemic disease causes new blood vessels will lead to delayed union or nonunion. Bone after transplantation, the activity of vascular granulation tissue ingrowth of bone grafts, bone graft is absorbed, take the initiative to the formation of new bone. However, in the large segment of bone grafts, this process slow and incomplete. The key to these problems lies in the revascularization of bone problems that plagued mankind for a long time.
Angiogenesis is an important part of the fracture healing process, a good blood supply to the fracture site of great significance in fracture repair. Vascular endothelial growth factor (vascular endothelial growth factor, VEGF) is a multifunctional cytokine, one of the most directly promotion of angiogenesis research has shown to play an important role of VEGF in bone formation and bone metabolism, the role is mainly by promoting angiogenesis involved in bone development in the form. Many recent studies have shown that VEGF is mainly derived from vascular endothelial cells is an important mediator of angiogenesis induced by multiple cytokines. On the other hand, increased expression levels of these cytokines will lead to increased expression of VEGF or synthetic. Various cytokines to promote bone efficacy and VEGF expression in varied ways, better application of what kind of cytokines, or combined with the feasibility of a variety of cytokines, there is no clear conclusion.
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