Wang Yongzhong, Blasioli Dominick J, Kim Hyeon-Joo, Kim Hyun Suk, Kaplan David L
Department of Chemical and Biological Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA.
Biomaterials. 2006 Sep;27(25):4434-42. doi: 10.1016/j.biomaterials.2006.03.050. Epub 2006 May 4.
Adult cartilage tissue has poor capability of self-repair, especially in case of severe cartilage damage due to trauma or age-related degeneration. Autologous cell-based tissue engineering using three-dimensional (3-D) porous scaffolds has provided an option for the repair of full thickness defects in adult cartilage tissue. Mesenchymal stem cells (MSCs) and chondrocytes are the two major cell sources for cartilage tissue engineering. Silk fibroin as a naturally occurring degradable fibrous protein with unique mechanical properties, excellent biocompatibility and process-ability has demonstrated strong potential for skeletal tissue engineering. The present study combined adult human chondrocytes (hCHs) with aqueous-derived porous silk fibroin scaffolds for in vitro cartilage tissue engineering. The results were compared with a previous study using the same scaffolds but using MSCs to generate the cartilage tissue outcomes. Culture-expanded hCHs attached to, proliferated and re-differentiated in the scaffolds in a serum-free, chemically defined medium containing TGF-beta1, based on cell morphology, levels of cartilage-related gene transcripts, and the presence of a cartilage-specific ECM. Cell density was critical for the redifferentiation of culture-expanded hCHs in the 3-D aqueous-derived silk fibroin scaffolds. The level of cartilage-related transcripts (AGC, Col-II, Sox 9 and Col-II/Col-I ratio) and the deposition of cartilage-specific ECM were significantly upregulated in constructs initiated with higher seeding density. The hCH-based constructs were significantly different than those formed from MSC-based constructs with respect to cell morphology, zonal structure and initial seeding density needed to successfully generate engineered cartilage-like tissue. These results suggest fundamental differences between stem cell-based (MSC) and primary cell-based (hCH) tissue engineering, as well as the importance of suitable scaffold features, in the optimization of cartilage-related outcomes in vitro. The present work diversifies cell sources in combination with silk fibroin-based tissue engineering applications. Together with our previous studies, the present results show great promise for engineered 3-D silk fibroin scaffolds in autologous cell-based skeletal tissue engineering.
成人软骨组织的自我修复能力较差，尤其是在因创伤或与年龄相关的退变导致严重软骨损伤的情况下。使用三维（3-D）多孔支架的基于自体细胞的组织工程为成人软骨组织全层缺损的修复提供了一种选择。间充质干细胞（MSCs）和软骨细胞是软骨组织工程的两种主要细胞来源。丝素蛋白作为一种天然存在的可降解纤维蛋白，具有独特的机械性能、优异的生物相容性和可加工性，已在骨骼组织工程中显示出强大的潜力。本研究将成人人类软骨细胞（hCHs）与水相衍生的多孔丝素蛋白支架相结合，用于体外软骨组织工程。将结果与先前一项使用相同支架但使用MSCs生成软骨组织结果的研究进行了比较。在含有转化生长因子-β1的无血清、化学成分明确的培养基中，培养扩增的hCHs基于细胞形态、软骨相关基因转录本水平以及软骨特异性细胞外基质（ECM）的存在，附着在支架上、增殖并重新分化。细胞密度对于培养扩增的hCHs在三维水相衍生丝素蛋白支架中的重新分化至关重要。在以较高接种密度起始构建的结构体中，软骨相关转录本（AGC、Ⅱ型胶原、Sox 9和Ⅱ型胶原/Ⅰ型胶原比率）水平和软骨特异性ECM的沉积显著上调。基于hCH的结构体在细胞形态、区域结构和成功生成工程化软骨样组织所需的初始接种密度方面与基于MSC的结构体显著不同。这些结果表明基于干细胞（MSC）和基于原代细胞（hCH）的组织工程之间存在根本差异，以及合适的支架特性在体外优化软骨相关结果中的重要性。本研究结合基于丝素蛋白的组织工程应用使细胞来源多样化。与我们之前的研究一起，目前的结果表明工程化三维丝素蛋白支架在基于自体细胞的骨骼组织工程中具有巨大潜力。
