Evaluation of cartilage tissue engineering strategies by IR imaging

描述(由申请人提供)： 当关节软骨因骨关节炎或损伤而受损时，组织有限 修复和再生的能力。因此，晚期骨关节炎的典型特征是广泛的软骨损伤，最终可导致关节置换术。人们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，但迄今收效甚微。一般说来，组织工程策略的目标是产生一种具有正常组织和分子结构并能承受负荷的软骨样组织。这种工程化结构的最佳发展需要在整个组织深度的宏观、微观和分子水平上了解组织的组成和结构。中红外光谱(MID-IR)是一种基于分子振动的技术，已被认为是评价软骨的一种重要方法。然而，中红外辐射的穿透深度被限制在~10微米以内，因此其应用仅限于表面评估。相比之下，同样基于分子振动的近红外光谱(NIRS)技术利用的是可以向上穿透组织的高频辐射 到几毫米的深度，因此有可能通过整个组织深度来监测体外工程组织的分子结构。为了实现这一目标，目前的提案试图将近红外光谱发展为一种在生长过程中评估工程软骨的方式。这将使工程化构建物能够在开发过程中根据需要使用适当的生长因子或机械输入进行修改，以优化组织结构。与这些研究相一致，这项建议的另一个目标是开发利用脉冲低强度超声(PLIUS)和生长因子形式的机械输入进行软骨组织工程和再生的策略，并使用近红外光谱和中红外光谱监测组织变化。我们将使用在中空纤维生物反应器中建立的软骨组织生长模型来进行大部分研究。总之，这些研究将证明，工程软骨基质可以成功地增强，并且利用近红外光谱模式的新应用，可以在体外监测基质分子成分的变化。 公共卫生相关声明(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工程组织在生长过程中的结构。近红外光谱评估可以提供监测组织体外生长的能力，从而允许对组织进行适当的干预 朝向所需的结构和成分终点改变组织的持续基础。因此，通过提供这种能力，这项技术的发展可能会在极其重要的组织工程领域发挥真正的核心作用。

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.