Toward Tissue Engineering of the Knee Meniscus

描述（由申请人提供）：申请的长期目标是使用一种有说服力的和全面的组织工程方法来成功地解决半月板再生问题，这仍然是肌肉骨骼医学中最难以捉摸的问题之一。该研究的主要假设是，半月板可以通过一系列步骤再生，包括使用带有生物活性剂、细胞、生物反应器、机械刺激和动物模型的支架。为了验证这一假设，我们提出了以下具体目标：1)设计、制造和表征半月板特异性生物可降解支架。2)设计半月板。3)在动物模型上测试半月板。该方法包括分析和合成阶段：在分析阶段，将使用生物力学、生物化学、超微结构方法和细胞培养来确定半月板的地形和空间特性。目的是确定“黄金标准”的性质，并与再生半月板的性质进行比较。在合成阶段，纤维软骨细胞将被植入半月板特异性支架并暴露在机械力下。支架由聚（富马酸丙烯-共乙二醇）制成，具有生物可吸收性，生物相容性，机械完整性，允许通过使用GRGD肽直接附着细胞，并通过使用生长因子提供生物合成信号。在低剪切环境下运行的流体动力聚焦生物反应器将用于增强营养物质的运输和调节机械信号。此外，还将使用定制的仪器检查静水压力和直接压缩/张力的影响。在不同的时间点，工程结构的性质将被量化，并与天然组织性质进行比较。组织工程构建体随后将被植入兔子体内，以评估新半月板的体内功能特征。由于半月板问题仍然是骨科中最令人烦恼的问题之一，因此本建议中所描述的方法的临床意义是巨大的。

DESCRIPTION (provided by applicant): The application's long-term objective is to use a cogent and comprehensive tissue engineering approach to successfully address meniscus regeneration, which remains one of the most elusive problems in musculoskeletal medicine. The study's main hypothesis is that the meniscus can be regenerated by a series of steps that involve the use of a scaffold with bioactive agents, cells, a bioreactor, mechanical stimuli, and an animal model. To test this hypothesis, we propose the following specific aims: 1) To design, fabricate, and characterize meniscus-specific biodegradable scaffolds. 2) To engineer the meniscus. 3) To test the meniscus in an animal model. The methodology involves an analysis and a synthesis phase: In the analysis phase, topographical and spatial properties of the meniscus will be identified using biomechanics, biochemistry, ultrastructural methods, and cell culture. The objective is to define 'gold standard' properties against which the properties of the regenerated meniscus will be compared. In the synthesis phase, fibrochondrocytes will be seeded onto meniscus-specific scaffolds and exposed to mechanical forces. The scaffolds, made of poly(propylene fumarate-co-ethylene glycol), are designed to be bioabsorbable, biocompatible, have mechanical integrity, allow for directed attachment of cells through the use of the GRGD peptide, and provide biosynthetic signals through the use of a growth factor. A hydrodynamic focusing bioreactor, operating in a low-shear environment, will then be used to enhance nutrient transport and to modulate mechanical signals. Furthermore, the effects of hydrostatic pressure and direct compression/tension will also be examined using custom-made instruments. At various time points, the properties of the engineered constructs will be quantified and compared to native tissue properties. The tissue engineered constructs will then be implanted in rabbits to evaluate the in vivo functional characteristics of the new meniscus. The clinical significance of the approach described in this proposal is enormous, since meniscal problems continue to be some of the most vexing in orthopaedics.