Farhadi Jian, Jaquiery Claude, Barbero Andrea, Jakob Marcel, Schaeren Stefan, Pierer Gerhard, Heberer Michael, Martin Ivan
Department of Surgery, University Hospital Basel, Basel, Switzerland.
Plast Reconstr Surg. 2005 Oct;116(5):1379-86. doi: 10.1097/01.prs.0000182355.67397.5a.
Bone tissue formation by bone marrow stromal cells may be supported and enhanced by multiple growth factors, particularly in cases of a compromised local microenvironment. In this study, the authors hypothesized that fibroblast growth factor (FGF)-2 can stimulate the production by human bone marrow stromal cells of osteogenic [i.e., bone morphogenetic protein (BMP)-2 and transforming growth factor (TGF)-beta1] and angiogenic [i.e., vascular endothelial growth factor (VEGF)] factors.
Human bone marrow stromal cells from six donors were expanded for two passages (expansion phase) and subsequently cultivated in osteogenic medium containing ascorbic acid, beta-glycerophosphate, and dexamethasone (differentiation phase). After each phase, cells were transferred into serum-free medium with or without FGF-2 at different concentrations and for different times, and the expression of BMP-2, TGF-beta1, and VEGF was quantified at the mRNA level by real-time quantitative reverse-transcriptase polymerase chain reaction. The amounts of TGF-beta1 and VEGF released in the culture medium were assessed using enzyme-linked immunosorbent assay kits and normalized to the DNA content.
In response to 5 ng/ml FGF-2 for 24 hours, the mRNA expression of VEGF increased at both culture phases (up to 6.1 fold), whereas that of BMP-2 and TGF-beta1 significantly increased only after the expansion (3.1-fold) or differentiation phase (2.1-fold), respectively. Similar trends were observed in the amounts of proteins measured in the culture medium.
The authors' results indicate that FGF-2 up-regulates the expression of BMP-2, TGF-beta1, and VEGF in human bone marrow stromal cells, in a pattern dependent on the cell-differentiation stage. These findings prompt for in vivo investigations on the delivery of FGF-2 for the temporally/functionally regulated enhancement of bone marrow stromal cell-based bone induction.
骨髓基质细胞形成骨组织的过程可能受到多种生长因子的支持和促进，尤其是在局部微环境受损的情况下。在本研究中，作者假设成纤维细胞生长因子（FGF）-2可刺激人骨髓基质细胞产生成骨因子[即骨形态发生蛋白（BMP）-2和转化生长因子（TGF）-β1]以及血管生成因子[即血管内皮生长因子（VEGF）]。
从6名供体获取的人骨髓基质细胞传代扩增2次（扩增阶段），随后在含有抗坏血酸、β-甘油磷酸和地塞米松的成骨培养基中培养（分化阶段）。在每个阶段后，将细胞转移至含或不含不同浓度FGF-2的无血清培养基中培养不同时间，通过实时定量逆转录聚合酶链反应在mRNA水平定量检测BMP-2、TGF-β1和VEGF的表达。使用酶联免疫吸附测定试剂盒评估培养基中释放的TGF-β1和VEGF量，并根据DNA含量进行标准化。
在两个培养阶段，5 ng/ml FGF-2作用24小时后，VEGF的mRNA表达均增加（高达6.1倍），而BMP-2和TGF-β1的mRNA表达仅在扩增阶段（3.1倍）或分化阶段（2.1倍）后显著增加。在培养基中检测的蛋白量也观察到类似趋势。
作者的结果表明，FGF-2上调人骨髓基质细胞中BMP-2、TGF-β1和VEGF的表达，其模式依赖于细胞分化阶段。这些发现促使对FGF-2递送进行体内研究，以在时间/功能上调节增强基于骨髓基质细胞的骨诱导。
