Department of Biomedical Engineering, Columbia University, New York, NY 10032, USA.
Osteoarthritis Cartilage. 2010 May;18(5):714-23. doi: 10.1016/j.joca.2010.01.008. Epub 2010 Feb 6.
The objective of the study was to investigate the combined effects of three sets of regulatory factors: cell pre-differentiation, soluble factors and medium perfusion on spatial control of human mesenchymal stem cell (hMSC) differentiation into cells forming the cartilaginous and bone regions in engineered osteochondral constructs.
Bone-marrow derived hMSCs were expanded in their undifferentiated state (UD) or pre-differentiated (PD) in monolayer culture, seeded into biphasic constructs by interfacing agarose gels and bone scaffolds and cultured for 5 weeks either statically (S) or in a bioreactor (BR) with perfusion of medium through the bone region. Each culture system was operated with medium containing either chondrogenic supplements (C) or a cocktail (Ck) of chondrogenic and osteogenic supplements.
The formation of engineered cartilage in the gel region was most enhanced by using undifferentiated cells and chondrogenic medium, whereas the cartilaginous properties were negatively affected by using pre-differentiated cells or the combination of perfusion and cocktail medium. The formation of engineered bone in the porous scaffold region was most enhanced by using pre-differentiated cells, perfusion and cocktail medium. Perfusion also enhanced the integration of bone and cartilage regions.
(1) Pre-differentiation of hMSCs before seeding on scaffold was beneficial for bone but not for cartilage formation. (2) The combination of medium perfusion and cocktail medium inhibited chondrogenesis of hMSCs. (3) Perfusion improved the cell and matrix distribution in the bone region and augmented the integration at the bone-cartilage interface. (4) Osteochondral grafts can be engineered by differentially regulating the culture conditions in the two regions of the scaffold seeded with hMSCs (hydrogel for cartilage, perfused porous scaffold for bone).
本研究旨在探讨三组调控因子（细胞预分化、可溶性因子和培养基灌注）对人骨髓间充质干细胞（hMSC）在工程化软骨-骨构建体中向软骨和骨区域细胞分化的空间控制的联合作用。
骨髓来源的 hMSC 在未分化状态（UD）或单层培养中预分化（PD）扩增，通过琼脂糖凝胶和骨支架的界面将其接种到双相构建体中，并在静态（S）或生物反应器（BR）中培养 5 周，培养基通过骨区域进行灌注。每个培养系统均使用含有软骨形成补充剂（C）或软骨形成和成骨补充剂鸡尾酒（Ck）的培养基进行操作。
使用未分化细胞和软骨形成培养基最能促进凝胶区域工程化软骨的形成，而使用预分化细胞或灌注和鸡尾酒培养基的组合则会对软骨特性产生负面影响。使用预分化细胞、灌注和鸡尾酒培养基最能促进多孔支架区域工程化骨的形成。灌注还增强了骨和软骨区域的整合。
（1）在接种支架之前对 hMSC 进行预分化有利于骨的形成，但不利于软骨的形成。（2）培养基灌注和鸡尾酒培养基的组合抑制了 hMSC 的软骨生成。（3）灌注改善了骨区域中细胞和基质的分布，并增强了骨-软骨界面的整合。（4）通过对接种 hMSC 的支架的两个区域（用于软骨的水凝胶、灌注的多孔支架用于骨）的培养条件进行差异调节，可以构建软骨-骨移植物。
