Trinity Centre for Bioengineering, School of Engineering, Trinity College Dublin, Ireland.
J Mech Behav Biomed Mater. 2012 Jul;11:102-11. doi: 10.1016/j.jmbbm.2011.09.004. Epub 2011 Sep 17.
MSCs from non-cartilaginous knee joint tissues such as the infrapatellar fat pad (IFP) and synovium possess significant chondrogenic potential and provide a readily available and clinically feasible source of chondroprogenitor cells. Fibroblast growth factor-2 (FGF-2) has been shown to be a potent mitotic stimulator during ex vivo expansion of MSCs, as well as regulating their subsequent differentiation potential. The objective of this study was to investigate the longer term effects of FGF-2 expansion on the functional development of cartilaginous tissues engineered using MSCs derived from the IFP. IFP MSCs were isolated and expanded to passage 2 in a standard media formulation with or without FGF-2 (5 ng/ml) supplementation. Expanded cells were encapsulated in agarose hydrogels, maintained in chondrogenic media for 42 days and analysed to determine their mechanical properties and biochemical composition. Culture media, collected at each feed, was also analysed for biochemical constituents. MSCs expanded in the presence of FGF-2 proliferated more rapidly, with higher cell yields and lower population doubling times. FGF-2 expanded MSCs generated the most mechanically functional tissue. Matrix accumulation was dramatically higher after 21 days for FGF-2 expanded MSCs, but decreased between day 21 and 42. By day 42, FGF-2 expanded MSCs had still accumulated ∼1.4 fold higher sGAG and ∼1.7 fold higher collagen compared to control groups. The total amount of sGAG synthesised (retained in hydrogels and released into the media) was ∼2.4 fold higher for FGF-2 expanded MSCs, with only ∼25% of the total amount generated being retained within the constructs. Further studies are required to investigate whether IFP derived MSCs have a diminished capacity to synthesise other matrix components important in the aggregation, assembly and retention of proteoglycans. In conclusion, expanding MSCs in the presence of FGF-2 rapidly accelerates chondrogenesis in 3D agarose cultures resulting in superior mechanical functionality.
从膝关节非软骨组织（如髌下脂肪垫和滑膜）中分离出来的间充质干细胞具有很强的软骨生成能力，并且是一种易于获得且具有临床可行性的软骨祖细胞来源。研究表明，成纤维细胞生长因子 2（FGF-2）在间充质干细胞的体外扩增过程中是一种有效的有丝分裂刺激物，同时也调节其随后的分化潜能。本研究旨在探讨 FGF-2 扩增对来源于髌下脂肪垫间充质干细胞的软骨组织工程的长期影响。将间充质干细胞分离并在标准培养基中扩增至第 2 代，培养基中添加或不添加 FGF-2（5ng/ml）。扩增后的细胞包被在琼脂糖水凝胶中，在软骨形成培养基中维持 42 天，并分析其力学性能和生化组成。还分析了每个饲料收集的培养基中的生化成分。在 FGF-2 存在下扩增的间充质干细胞增殖更快，细胞产量更高，倍增时间更短。FGF-2 扩增的间充质干细胞产生的组织力学功能最强。FGF-2 扩增的间充质干细胞在第 21 天的基质积累量显著增加，但在第 21 天至第 42 天之间减少。到第 42 天，FGF-2 扩增的间充质干细胞的 sGAG 仍累积了约 1.4 倍，胶原蛋白累积了约 1.7 倍，与对照组相比。FGF-2 扩增的间充质干细胞合成的 sGAG 总量（保留在水凝胶中和释放到培养基中）约为 2.4 倍，其中仅约 25%的总量保留在构建物中。需要进一步研究，以探讨来源于髌下脂肪垫的间充质干细胞是否具有合成其他在聚集、组装和保留蛋白聚糖方面重要的基质成分的能力下降。总之，在 FGF-2 的存在下扩增间充质干细胞可快速加速 3D 琼脂糖培养中的软骨生成，从而产生更好的力学功能。
