Evaluation of cartilage tissue engineering strategies by IR imaging

描述（由申请人提供）： 当关节软骨由于骨关节炎或损伤而受损时，该组织具有有限的 修复和再生能力。因此，晚期OA的典型特征是广泛的软骨损伤，最终可能导致关节成形术。已经对修复受损软骨的技术进行了广泛的研究，包括开发工程化软骨结构作为替代组织，迄今为止成功有限。一般来说，组织工程策略的目标是产生具有正常组织和分子结构并且能够承受负荷的软骨样组织。这种工程化构建体的最佳开发需要通过整个组织深度在宏观、微观和分子水平上了解组织的组成和结构。中红外（中红外）光谱，一种基于分子振动的技术，以前已被确立为软骨评估的重要方法。然而，中红外辐射的穿透深度仅限于~10微米，因此其使用仅限于表面评估。相比之下，近红外光谱（NIRS），一种也基于分子振动的技术，利用更高频率的辐射，可以穿透组织向上， 到几毫米的深度，因此具有通过整个组织深度在体外监测工程组织的分子结构的潜力。为了实现这一目标，目前的建议旨在发展近红外光谱作为一种模式，以评估工程软骨生长过程中。这将使工程化的构建体能够在开发期间根据需要用适当的生长因子或机械输入进行修饰，以优化组织结构。与这些研究相一致，本提案的另一个目标是开发软骨组织工程和再生的策略，使用机械输入的形式，脉冲低强度超声（CIMUS）和生长因子，并监测组织的变化，使用近红外光谱和中红外光谱。我们将使用一个既定的模型，软骨组织生长在中空纤维生物反应器的大部分研究。总之，这些研究将证明，工程软骨基质可以成功地被增强，并且可以利用NIRS模式的新应用在体外监测基质分子组分的变化。 公共卫生相关性声明（由申请人提供）：在为受损软骨生成替代组织方面取得进展的一个重大障碍是无法评估生长期间工程组织的结构。近红外光谱评估可以提供在体外监测组织生长的能力，从而允许对组织进行适当的干预。 一个持续的基础，以修改组织向所需的结构和组成的终点。因此，这项技术的发展可能会发挥真正的核心作用，在非常重要的领域组织工程提供这种能力。

DESCRIPTION (provided by applicant): When articular cartilage is damaged as a result of osteoarthritis or injury, the tissue has limited capacity for repair and regeneration. As such, advanced stages of OA are typically characterized by extensive cartilage damage that can eventually lead to joint arthroplasty. There has been extensive research into techniques to repair damaged cartilage, including development of engineered cartilage constructs as replacement tissues, with limited success to date. In general, the goal of tissue engineering strategies is to produce a cartilage-like tissue that has a normal organization and molecular structure, and can sustain load. The optimal development of such engineered constructs requires knowledge of the composition and structure of the tissue at the macroscopic, microscopic and molecular levels through the full tissue depth. Mid-infrared (mid-IR) spectroscopy, a technique based on molecular vibrations, has previously been established as an important approach for cartilage evaluation. However, the penetration depth of mid-IR radiation is limited to ~10 microns, so that its use is restricted to surface evaluation. In contrast, near infrared spectroscopy (NIRS), a technique also based on molecular vibrations, utilizes higher frequency radiation that can penetrate tissue up to several millimeters in depth, and therefore has the potential to monitor the molecular structure of engineered tissue in vitro through the full tissue depth. Towards this goal, the current proposal seeks to develop NIRS as a modality to assess engineered cartilage during growth. This would enable engineered constructs to be modified with appropriate growth factors or mechanical input as required during development to optimize tissue structure. In concert with these studies, a further goal of this proposal is to develop strategies for cartilage tissue engineering and regeneration using mechanical input in the form of pulsed low intensity ultrasound (PLIUS) and growth factors, and to monitor the tissue changes using both NIRS and mid-IR. We will use an established model of cartilage tissue growth in a hollow fiber bioreactor for the majority of the studies. Together, these studies will demonstrate that engineered cartilage matrix can successfully be augmented, and that the changes in molecular components of the matrix can be monitored in vitro utilizing the novel application of the NIRS modality. Public Health Relevance Statement (provided by applicant): A significant impediment to advances in generating replacement tissues for damaged cartilage is the inability to assess the structure of an engineered tissue during growth. Near-infrared spectroscopic assessment could offer the ability to monitor tissue growth in vitro, and thus permit appropriate interventions to be undertaken on an ongoing basis to modify the tissue towards desired structural and compositional endpoints. Therefore, the development of this technique may play a truly central role in the exceedingly important field of tissue engineering by offering this capability.