Raman spectroscopic platform for transcutaneous monitoring of bone quality

项目摘要 在没有严重创伤的情况下发生的骨脆性骨折通常与原发性或继发性骨折有关。 继发性骨质疏松症，并可能导致严重的患者发病率和死亡率增加。预测 骨折风险主要依赖于骨矿物质密度（BMD）的测量， 骨强度，但没有骨折风险。或者，拉曼光谱（RS），一种可以 提供矿物结晶度、成分和相对矿化度（矿物/基质）的信息 比例），以及胶原蛋白组成和交联，已经成为一种有前途的技术， 评估骨强度和骨折风险。我们最近发现RS可以检测生物化学物质， 在类风湿性关节炎（RA）、糖皮质激素（GC）诱导的骨质疏松症的小鼠模型中发生的变化 （GIOP）和成骨不全，与生物力学强度的独立测量相关 和断裂韧性。我们还开发了仪器，使第一个诊断敏感的 完整肢体上鼠骨的经皮拉曼测量，沿着复杂的算法， 减少覆盖软组织的光学贡献，但这些测量仅在体外进行， 组织标本在此应用中，我们将开发新的仪器和算法，以适应我们的 活体动物的经皮RS测量。更重要的是，根据未公布的数据， 证明骨端（骨骺）比骨干中段（骨干）表现出更明显的RS差异 地区，我们将重新设计我们的RS平台中的激发/收集光学器件，以提供更大范围的光源， 探测器分离，更大的多样性，在采样深度，并最终提高能力，以解决光谱 在解剖学和生物化学上更复杂的骨骺中， 区域（目标1）。然后，我们将经皮验证和关联区域（骨骺与骨干） 拉曼光谱测量与区域和整个骨力学（骨质测量）， 幼年、成年和老年小鼠（目标2）。最后，这些研究将表明，我们的 经皮RS平台具有检测小鼠骨质量纵向降低的灵敏度 随着时间的推移，RA和GIOP模型，以及抗吸收和 合成代谢治疗（目标3）。完成后，拟议的研究将验证一项颠覆性技术 用于骨脆性和骨折风险的临床前、非接触式光学评估， 标准度量，如BMD。虽然这项工作的成功完成将产生一个新的文书，在我们的 研究工具箱，以促进我们对骨质疏松症机制的理解，并评估新的 我们希望我们在这里取得的进展将允许这种非侵入性技术， 在不久的将来，它将被扩大并转化为临床上的实验性诊断工具。

Project Summary Bone fragility fractures that occur in the absence of significant trauma are often associated with primary or secondary osteoporosis, and can result in serious patient morbidity and increased mortality rates. Prediction of bone fracture risk primarily relies on measures of bone mineral density (BMD), which is strongly correlated with bone strength, but not with fracture risk. Alternatively, Raman spectroscopy (RS), an optical technique that can provide information on mineral crystallinity, composition, and relative degree of mineralization (mineral/matrix ratio), as well as collagen composition and cross-linking, has emerged as a promising technique for assessment of bone strength and fracture risk. We have recently shown that RS can detect biochemical changes that occur in mouse models of rheumatoid arthritis (RA), glucocorticoid (GC)-induced osteoporosis (GIOP), and osteogenesis imperfecta, which correlated with independent measures of biomechanical strength and fracture toughness. We have also developed instrumentation to enable the first diagnostically-sensitive transcutaneous Raman measurements of murine bone on intact limbs, along with sophisticated algorithms to reduce optical contributions from overlying soft tissue, but these measurements were only made ex vivo on tissue specimens. In this application, we will develop new instrumentation and algorithms to adapt our transcutaneous RS measurements on live animals. More importantly, based on unpublished data demonstrating that bone ends (epiphyses) exhibit more discriminate RS differences than mid-shaft (diaphysis) regions, we will redesign the excitation/collection optics in our RS platform to provide a larger range of source- detector separation, greater variety in sampling depth, and ultimately improve the ability to resolve the spectral contributions from interfering soft tissues in the more anatomically and biochemically complex epiphyses regions (Aim 1). We will then validate and correlate regional (epiphysis versus diaphysis) transcutaneous Raman spectroscopy measurements with regional and whole bone mechanics (measures of bone quality) in juvenile, skeletally mature, and aged mice (Aim 2). Finally, the studies will demonstrate that our transcutaneous RS platform has the sensitivity to detect longitudinal reductions in bone quality in mouse models of RA and GIOP over time, and improvements in bone quality in response to anti-resorptive and anabolic treatments (Aim 3). Upon completion, the proposed studies will have validated a disruptive technology for pre-clinical, non-contact optical assessment of bone fragility and fracture risk, which are undetectable by standard metrics such as BMD. While successful completion of this work will yield a new instrument in our research toolbox to advance our understanding of mechanisms of osteoporosis and to evaluate efficacy of new drugs in preclinical models, we hope that the progress we make here will allow this non-invasive technology to be scaled-up and translated in the not too distant future as an experimental diagnostic tool in the clinic.