Shear Force Effects on Superficial Cartilage Regeneration

肌肉骨骼疾病和损伤通常会导致关节软骨的损伤。这些软骨缺损几乎没有固有的修复能力。目前的临床治疗是不充分的，因为它们经常导致纤维软骨形成和关节疼痛。本研究的目的是培养专门用于浅层软骨再生的软骨细胞。这一策略的前提是为临床医生提供一种早期干预方法，同时也可以防止形成更多的使人衰弱的缺陷。该小组最近证明了从原代间充质干细胞（MSCs）中获得骨软骨祖细胞（OPCs）的能力，并表明这些OPCs对胰岛素样生长因子-1 （IGF-1）有反应，IGF-1是一种与功能性关节软骨相关的合成代谢生长因子。研究表明，透明质酸（HA）可导致软骨细胞表面带蛋白（SZP）的表达上调，而SZP是浅表带软骨细胞的关键表型标志物。这些结果导致了以下假设的发展。据推测，人间充质干细胞在软骨培养基中的动态培养将为软骨细胞的快速分化提供一个有利的环境。具体而言，动态培养条件所提供的氧气和营养物质运输的增强将促进hMSC的活力和增殖，而tgf - β 3的传递和灌注成软骨培养基所赋予的剪切力将促进软骨细胞分化。为了检验这一假设，将开发动态培养参数，以指导MSC分化为OPCs。其次，据推测，IGF-1向骨软骨祖细胞的受控递送会促进其成熟为分化的浅表带软骨细胞，PRG4和II型胶原的表达上调证明了这一点。此外，我们还假设工程化浅层软骨可以有效地治疗大鼠关节软骨浅层缺损。为了验证这些假设，将在TPS生物反应器环境中将外源性IGF-1输送到骨软骨祖细胞中，并评估其向浅层软骨细胞的成熟程度，如PRG4和II型胶原生成所示，然后利用这种工程构建物在大鼠模型中再生浅层软骨。更广泛的影响这个项目的更广泛的影响包括工程组织的发展和再生医学新策略和技术的阐明。此外，在多个教育层面加强生物医学工程研究是这项工作影响的一个关键方面。与该提案相关的关键活动将是开发和执行与马里兰大学工程世界卫生（EWH）章节相关的一系列新项目。世卫组织的目标是创造并向发展中国家分发易于实施的生物医学技术。在2011-2012年的第一年，PI与马里兰州EWH分会合作实现了这些目标。PI还将继续开展许多影响本科和研究生教育的活动。例如，PI目前指导本科生建模生理系统和实验室课程，以及本科生/研究生组织工程课程。自2007年以来，PI一直指导本科生分子细胞生物工程研究经验网站。到目前为止，分子细胞生物工程REU站点已经吸引了大约60名来自全国各地的学生到Fischell生物工程系的相关教师实验室工作。最后，PI目前担任Fischell生物工程系的副主席和本科研究主任。在这个职位上，PI在培养本科生物工程教育的课程、项目和研究水平上有直接的影响。由生物医学工程（CBET）和生物研究仪器开发（BIO理事会）联合资助

PI: John P FisherAward ID: 1264517Intellectual MeritMusculoskeletal disease and injury can commonly result in damage to articular cartilage. These cartilage defects have little inherent ability to repair. Current clinical treatments are inadequate as they often lead to fibrocartilage formation and joint pain. The goal of this proposal is to develop chondrocytes specifically for superficial zone cartilage regeneration. The premise of this strategy is to provide clinicians with an early stage intervention approach, and one that would also prevent the formation of more debilitating defects. This group has recently demonstrated the ability to derive osteochondroprogentior cells (OPCs) from primary mesenchymal stem cells (MSCs) and shown these OPCs to be responsive to insulin-like growth factor-1 (IGF-1), an anabolic growth factor associated with functional articular cartilage. It has been shown that hyaluronic acid (HA) can lead to up-regulate chondrocytic expression of superficial zone protein (SZP), a key phenotypic marker for superficial zone chondrocytes. These results led to the development of the following hypotheses. It is hypothesized that the dynamic culture of human mesenchymal stem cells within chondrogenic media will provide an environment conducive for rapid chondrocytic differentiation. Specifically, enhanced oxygen and nutrient transport, provided by the dynamic culture conditions, will promote hMSC viability and proliferation, while TGF-beta3 delivery and shear forces imparted the by perfusing chondrogenic media will promote chondrocytic differentiation. To examine this hypothesis, dynamic culture parameters will be developed so as to direct MSC differentiation into OPCs. Second, it is hypothesized that controlled delivery of IGF-1 to osteochondroprogenitor cells will encourage their maturation to differentiated superficial zone chondrocytes, as demonstrated by up-regulated PRG4 and type II collagen expression. In addition, it is hypothesized that engineered superficial zone cartilage can effectively treat superficial articular cartilage defects in a rat model. To examine these hypotheses, delivery exogenous IGF-1 to osteochondroprogenitor cells within the TPS bioreactor environment will be performed and their maturation into superficial zone chondrocytes will be assessed as well, as indicated by PRG4 and type II collagen production, and then utilize this engineered construct to regenerate superficial zone cartilage in a rat model.Broader ImpactsThe broader impacts of this project include the development of an engineered tissue and the elucidation of new strategies and technologies within regenerative medicine. In addition, enhancing biomedical engineering research at multiple education levels is a key aspect of the work's impact. The key activity related to this proposal will be the development and execution of a new series of projects associated with the Engineering World Health (EWH) chapter at the University of Maryland. EWH aims to create and distribute readily implementable biomedical technologies to developing countries. The PI has worked with the EWH chapter at Maryland during it inaugural year in 2011-2012 to realize these goals. The PI will also continue many activities that impact undergraduate and graduate education. For example, the PI currently instructs an undergraduate Modeling Physiological Systems and Laboratory course, and an undergraduate / graduate Tissue Engineering course. Since 2007, the PI has directed the Molecular & Cellular Bioengineering Research Experiences for Undergraduates Site. To date, the Molecular & Cellular Bioengineering REU site has brought approximately 60 students from around the country to work in the laboratories of faculty associated with the Fischell Department of Bioengineering. Finally, the PI currently acts as the Associate Chair and Director of Undergraduate Studies in the Fischell Department of Bioengineering. In this position, the PI has a direct influence in fostering undergraduate bioengineering education at the curriculum, program, and research levels.Jointly funded by Biomedical Engineering (CBET) and Instrument Development for Biological Research (BIO Directorate)