Advancing Raman spectroscopy toward the clinical assessment of bone quality

推动拉曼光谱应用于骨质量的临床评估

• 批准号: 9752446
• 负责人: Jeffry Stephen Nyman
• 金额: $ 17.34万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-30 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9752446
• 关键词: Address; Advanced Glycosylation End Products; Age; Amides; Anterior; Architecture; Basic Science; Biochemical; Biological Assay; Bone Density; Bone Diseases; Bone Matrix; Cadaver; Characteristics; Clinical; Clinical assessments; Collagen; Collagen Type I; Diagnostic; Disease; Distal; Dual-Energy X-Ray Absorptiometry; Emerging Technologies; Epidemiology; Evaluation; Excision; Extracellular Matrix; Fatigue; Femur; Fiber Optics; Fluorescence; Fracture; Geometry; Glucose; Goals; Hand; Head and neck structure; Human; Image; Imaging Techniques; Incubated; Individual; Laboratories; Light; Linear Models; Measurement; Measures; Mechanics; Medial; Mediating; Methods; Minerals; Modification; Multivariate Analysis; Nature; Optics; Patients; Periodicity; Phase; Porosity; Process; Proline; Property; Raman Spectrum Analysis; Research; Research Personnel; Resistance; Risk; Sampling; Shapes; Side; Site; Solubility; Specificity; Specimen; Spectrum Analysis; Structure; System; Techniques; Technology; Tensile Strength; Testing; Thick; Time; Translating; Water; Work; X-Ray Computed Tomography; base; bone; bone quality; clinical diagnostics; clinical imaging; cortical bone; crosslink; demineralization; density; efficacy study; fracture risk; inorganic phosphate; instrument; mechanical properties; mineralization; notch protein; polarized light; pre-clinical; preservation; soft tissue; substantia spongiosa; sugar; tibia; tool; trait

Fracture resistance depends on the shape of the whole bone with respect to loading, the microstructure of both cortical and trabecular bone, and the ultrastructure of the extracellular matrix or the inherent quality of the bone matrix. While advances in clinical imaging provide measurements of cortical thickness, cortical cross-sectional geometry, cortical porosity, trabecular micro-architecture, as well as volumetric mineral density and matrix- bound water (at distal sites), clinical tools are currently not available to assess the contribution of matrix composition and organization to fracture resistance. Raman spectroscopy (RS) is one technology well suited to fill this gap in clinical diagnostics of bone because it is i) relatively inexpensive and safe with rapid acquisition times, ii) sensitive to both the mineral phase and the organic matrix, and iii) easy-to-use in which a hand-held probe acquires the spectra. There are however several obstacles to overcome in order for RS to provide clinically meaningful assessments of bone matrix quality: i) identify the best strategy to acquire the Raman spectra from bone (transcutaneous vs. percutaneous with or without polarization preserving optics) and ii) determine how to analyze the spectra such that Raman measurements can assess fracture resistance (peak ratios vs. sub-band peak ratios vs. full spectrum analysis). Addressing these challenges, the project will assess the ability of RS to predict mechanical properties of human cortical bone and do so with respect to volumetric bone mineral density (vBMD) and age (Aim 1) and will identify the matrix factors that influence Raman spectroscopic properties of bone quality (Aim 2). For Aim 1, Raman spectra will be acquired from the medial side of the tibia mid-shaft near the anterior ridge (shin) using first a spatially offset RS probe, then using a small fiber optic Raman probe after soft tissue removal, and lastly using a confocal Raman instrument that preserves polarization of the light. Next, mechanical specimens will be extracted from each cadaveric mid-shaft as well as the femoral neck and head, imaged by micro-computed tomography to determine vBMD, and then subjected to tensile testing, fracture toughness testing, or compressive fatigue testing. General linear models will be used to determine whether Raman properties help age and vBMD explain the variance in strength, toughness, fracture toughness, and fatigue resistance (i.e., they add value). Based on preliminary work, we expect a sub-peak ratio within the Amide I to be a predictor of fracture resistance. For Aim 2, pieces of bone from the mechanical specimens (away from test region) will be demineralized and subjected to biochemical assays to determine collagen crosslink concentrations, fluorescent advanced glycation end-products (AGEs), percentage of denatured collagen, and degree of collagen solubility. In addition, Raman spectra will be acquired before and after AGE accumulation and fatigue loading using separate bone samples (mineralized). Since the shape of the Amide I band is reflective of the secondary structure of type 1 collagen, we expect sub- peak ratios to be sensitive to degree of AGE crosslinks and the degree to which the collagen is helical.

抗折性取决于整个骨骼在负载方面的形状、两者的微观结构 皮质骨和小梁骨，以及细胞外基质的超微结构或骨的内在质量 矩阵。虽然临床成像的进步提供了皮质厚度、皮质横截面的测量 几何形状、皮质孔隙度、小梁微结构以及体积矿物密度和基质 结合水（在远端部位），目前无法使用临床工具来评估基质的贡献 抗断裂性的成分和组织。拉曼光谱 (RS) 是一项非常适合 填补了骨临床诊断方面的这一空白，因为它 i) 相对便宜且安全，且采集速度快 次，ii) 对矿物相和有机基质均敏感，以及 iii) 易于使用，其中手持式 探针获取光谱。然而，为了让 RS 能够提供 对骨基质质量有临床意义的评估：i) 确定获取拉曼光谱的最佳策略 来自骨的光谱（经皮与经皮，有或没有保偏光学器件）和 ii) 确定如何分析光谱，以便拉曼测量可以评估断裂阻力（峰值 比率与子带峰值比率与全频谱分析）。为了应对这些挑战，该项目将评估 RS 预测人类皮质骨的机械特性并根据体积进行预测的能力 骨矿物质密度 (vBMD) 和年龄（目标 1），并将确定影响拉曼的基质因素 骨质量的光谱特性（目标 2）。对于目标 1，将从内侧获取拉曼光谱 首先使用空间偏置 RS 探头，然后使用靠近前脊（胫骨）的胫骨中轴一侧 软组织去除后使用小型光纤拉曼探头，最后使用共焦拉曼仪器 保持光的偏振。接下来，将从每具尸体中轴中提取机械标本 以及股骨颈和股骨头，通过微型计算机断层扫描成像以确定 vBMD，然后 进行拉伸试验、断裂韧性试验或压缩疲劳试验。一般线性模型 将用于确定拉曼特性是否有助于年龄和 vBMD 解释强度差异， 韧性、断裂韧性和抗疲劳性（即它们增加了价值）。在前期工作的基础上，我们 预期酰胺 I 内的亚峰比率可作为抗断裂性的预测指标。对于目标 2，骨头碎片 从机械样本（远离测试区域）中去除矿物质并进行生化处理 测定胶原交联浓度、荧光晚期糖基化终产物 (AGE)、 变性胶原蛋白的百分比和胶原蛋白溶解度。此外，拉曼光谱将 使用单独的骨样本（矿化）在 AGE 积累和疲劳负荷之前和之后获得。 由于酰胺 I 带的形状反映了 1 型胶原蛋白的二级结构，因此我们预计亚 峰值比率对 AGE 交联程度和胶原蛋白螺旋程度敏感。