Dorcemus Deborah L, George Eve O, Dealy Caroline N, Nukavarapu Syam P
1 Department of Biomedical Engineering, University of Connecticut , Storrs, Connecticut.
2 Institute for Regenerative Engineering, UCONN Health , Farmington, Connecticut.
Tissue Eng Part A. 2017 Aug;23(15-16):719-737. doi: 10.1089/ten.tea.2016.0439. Epub 2017 Mar 24.
Over the last decade, engineered structures have been developed for osteochondral (OC) tissue regeneration. While the optimal structure design is yet to be determined, these scaffolds require in vitro evaluation before clinical use. However, the means by which complex scaffolds, such as OC scaffolds, can be tested are limited. Taking advantage of a mesenchymal stem cell's (MSC's) ability to respond to its surrounding we harness external cues, such as the cell's mechanical environment and delivered factors, to create an in vitro culture system for OC tissue engineering with a single cell source on a gradient yet integrated scaffold system. To do this, the effect of hydrogel stiffness on the expression of human MSCs (hMSCs) chondrogenic differentiation was studied using histological analysis. Additionally, hMSCs were also cultured in different combinations of chondrogenic and osteogenic media to develop a co-differentiation media suitable for OC lineage differentiation. A uniquely graded (density-gradient matrix) OC scaffold with a distal cartilage hydrogel phase specifically tailored to support chondrogenic differentiation was cultured using a newly developed "simulated in vivo culture method." The scaffold's culture in co-differentiation media models hMSC infiltration into the scaffold and subsequent differentiation into the distal cartilage and proximal bone layers. Cartilage and bone marker staining along with specific matrix depositions reveal the effect of external cues on the hMSC differentiation. As a result of these studies a model system was developed to study and culture OC scaffolds in vitro.
在过去十年中，已开发出用于骨软骨（OC）组织再生的工程结构。虽然最佳结构设计尚未确定，但这些支架在临床应用前需要进行体外评估。然而，测试复杂支架（如OC支架）的方法有限。利用间充质干细胞（MSC）对其周围环境作出反应的能力，我们利用外部线索，如细胞的机械环境和递送因子，在梯度但一体化的支架系统上创建一个具有单一细胞来源的用于OC组织工程的体外培养系统。为此，使用组织学分析研究了水凝胶硬度对人MSC（hMSC）软骨分化表达的影响。此外，hMSC还在软骨生成和成骨培养基的不同组合中培养，以开发适合OC谱系分化的共分化培养基。使用新开发的“模拟体内培养方法”培养一种独特的分级（密度梯度基质）OC支架，其远端软骨水凝胶相经过专门设计以支持软骨分化。在共分化培养基中培养该支架可模拟hMSC浸润到支架中并随后分化为远端软骨层和近端骨层。软骨和骨标志物染色以及特定的基质沉积揭示了外部线索对hMSC分化的影响。这些研究的结果是开发了一个用于体外研究和培养OC支架的模型系统。
