NMR Spectral Markers of Cartilage Degeneration in Osteoarthritis

描述(由申请人提供)：骨关节炎(OA)是一个主要的健康问题，治疗选择非常有限。了解骨关节炎软骨的生化和分子变化可以为新的治疗靶点提供线索。此外，显然需要活体成像技术，能够非侵入性和批判性地评估新治疗方法的治疗效果。磁共振成像(MRI)已被用于研究软骨退变，通过观察水分含量、松弛和扩散的变化。然而，这些变化是退行性软骨中蛋白多糖(PG)/胶原基质变化的间接副产品，并不提供生化变化的直接衡量标准。这就是我们的研究想要填补的空白。高分辨率魔角旋转(HRMAS)光谱学是一种独特的非破坏性体外技术，可以提供对组织生化变化的直接测量。然而，HRMAS在人软骨中的应用研究非常有限，而且HRMAS测量的生化变化与软骨退变之间的关系尚未建立。我们的长期目标是开发早期软骨退变的非侵入性成像标记物。这项建议的目的是开发和验证体外HRMAS技术，以评估与骨关节炎相关的软骨基质的生化变化。核心假设是HRMAS的非破坏性成像能力将导致识别早期软骨退变的光谱标记物，这些标记物可能与骨关节炎软骨基质中的分子变化有关，如PG/胶原降解。这项研究是开发一种新的、活体的、非侵入性的诊断工具的必要的第一步，该工具可以为早期OA提供直接的软骨生化测量。具体地说，我们将1)建立和优化人类软骨的HRMAS采集协议；2)使用HRMAS识别与软骨退变相关的生化变化。软骨样本将从接受全膝关节置换术的OA患者和身体膝关节(对照组)中获取。软骨退行性变将通过组织学进行评估。将比较对照组和骨性关节炎样本之间的HRMAS测量，并识别软骨退变的HRMAS光谱标记。HRMAS测定将与PG和胶原测定定量以及聚集素和胶原裂解新表位的免疫组织化学分析相关联。该项目在开发和应用体外HRMAS技术来表征人骨关节炎软骨的生化变化方面具有新颖性。这项研究的临床意义和激动人心之处在于，这项研究未来将扩展到活体磁共振光谱学。公共卫生相关性：骨关节炎(OA)影响着2500多万美国人，是导致残疾的主要原因之一。目前对骨性关节炎的治疗非常有限，早期软骨退变的诊断仍然是一个挑战。该建议旨在开发一种新的体外核磁共振方法，以探索骨关节炎软骨退变的光谱标记物。这项研究是开发一种新的、非侵入性的诊断工具的关键的第一步，该工具可以为早期OA提供直接的软骨生化测量，这将显著改善OA的患者管理和临床护理。

DESCRIPTION (provided by applicant): Osteoarthritis (OA) is a major health concern with very limited treatment options. Understanding biochemical and molecular changes in OA cartilage can provide clues for new therapeutic targets. Furthermore, there is clearly a need for in vivo imaging techniques that can non-invasively and critically evaluate the therapeutic efficacy of new treatment methods. Magnetic resonance imaging (MRI) has been used to study cartilage degeneration by observing the changes in water content, relaxation and diffusion. However, these changes are indirect by-products of alterations in proteoglycan (PG)/collagen matrix in degenerative cartilage, and do not provide direct measures of biochemical changes. This is the gap our research is intended to fill. High Resolution - Magic Angle Spinning (HRMAS) spectroscopy is a unique non-destructive ex vivo technique that can provide direct measurement of biochemical changes in tissues. However, studies using HRMAS in human cartilage are very limited and no relationship between biochemical changes measured by HRMAS and cartilage degeneration has been established. Our long-term goal is to develop non-invasive imaging markers for early degeneration of cartilage. The goal of this proposal is to develop and validate ex vivo HRMAS techniques for evaluating biochemical changes in cartilage matrix associated with OA. The central hypothesis is that the non-destructive imaging capability of HRMAS will lead to identification of spectroscopic markers of early cartilage degeneration that can be related to the molecular changes in osteoarthritic cartilage matrix such as PG/collagen degradation. This research is an essential first step in the development of a novel, in vivo, non-invasive diagnostic tool that provides direct measurement of cartilage biochemistry for early OA. Specifically, we will 1) establish and optimize HRMAS acquisition protocols in human cartilage; 2) identify biochemical changes associated with cartilage degeneration using HRMAS. Cartilage samples will be harvested from OA patients who undergo total knee replacement and cadaver knees (controls). Cartilage degeneration will be evaluated using histology. HRMAS measurement between control and OA samples will be compared and HRMAS spectral markers for cartilage degeneration will be identified. HRMAS measurement will be correlated with PG and collagen assay quantitation as well as with immnohistochemical analysis on aggrecan and collagen cleavage neoepitopes. This project is novel in developing and applying ex vivo HRMAS techniques to characterize biochemical changes in human OA cartilage. The future extension of this to in vivo MR spectroscopy is what makes this study clinically significant and exciting. PUBLIC HEALTH RELEVANCE: Osteoarthritis (OA) affects more than 25 million Americans and is one of the leading causes of disability. Current treatment to OA is very limited and diagnosis of early cartilage degeneration remains a challenge. This proposal aims at developing a novel ex vivo NMR method to explore spectral markers for cartilage degeneration in OA. This research is an essential first step in the development of a novel, non-invasive, diagnostic tool that provides direct measurement of cartilage biochemistry for early OA, which will significantly improve patient management and clinical care of OA.