The Role of Tissue Matrix in the Fracture Resistance of Diabetic Bone

组织基质在糖尿病骨抗骨折中的作用

• 批准号: 9317431
• 负责人: Jeffry Stephen Nyman
• 金额: $ 17.38万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-18 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9317431
• 关键词: Address; Advanced Glycosylation End Products; Affect; Age; Amides; Architecture; Binding; Binding Proteins; Biochemical; Biomechanics; Bone Density; Bone Matrix; Bone Tissue; Cadaver; Carbonates; Characteristics; Clinical; Collagen; Collagen Type I; Defect; Diabetes Mellitus; Diabetic mouse; Diagnostic; Diagnostic Procedure; Dual-Energy X-Ray Absorptiometry; Elderly; Enzymes; Femur; Fracture; Goals; Human; Hydrogen Bonding; Hydroxylation; Hydroxylysine; Hydroxyproline; Individual; Knowledge; Linear Models; Mass Spectrum Analysis; Measurement; Measures; Mechanics; Mediating; Minerals; Modification; Modulus; Molecular; Mus; N(6)-carboxymethyllysine; Non-Insulin-Dependent Diabetes Mellitus; Nuclear Magnetic Resonance; Osteocalcin; Pathogenicity; Population; Porosity; Post-Translational Modification Alteration; Post-Translational Protein Processing; Predictive Value; Property; Raman Spectrum Analysis; Research; Resistance; Risk; Role; Sampling; Series; Shapes; Site; Stress; Structure; Techniques; Technology; Testing; Tissues; Water; Work; X-Ray Computed Tomography; analytical tool; base; bone; bone fragility; bone quality; bone strength; carboxylation; clinical diagnostics; clinically relevant; clinically translatable; cortical bone; crosslink; crystallinity; density; diabetic; diabetic patient; fracture risk; glycosylation; improved; liquid chromatography mass spectrometry; mechanical properties; mouse model; new therapeutic target; non-diabetic; novel; novel diagnostics; novel strategies; pentosidine; pre-clinical; prevent; tool

Project Summary The increasing risk of bone fracture with the progression of diabetes is not solely due to reduced bone mineral density (BMD). Since BMD is seemingly normal or even elevated among those with type 2 diabetes, lowering fracture risk among type 2 diabetics requires an understanding of what aspects within the bone tissue matrix contribute to the increase in fracture risk. In addressing this clinically relevant problem, we propose i) to identify pathogenic changes in the bone tissue matrix that contribute to bone fragility as diabetes progresses and ii) to determine how well clinically translatable diagnostic tools (sensitive to the matrix and the mineral of the bone) reflect the diabetes-related changes in fracture resistance. We hypothesize that i) a decrease in the bound water within the bone matrix contributes significantly to the increased fragility of the diabetic bone, ii) a decrease in the matrix bound water is due to diabetes-induced changes in post-translational modifications (PTMs) within bone matrix, and iii) tools capable of measuring bound water in the bone, secondary structure of collagen, and tissue indentation resistance can be used to assess fracture resistance in diabetes. In Aim 1, we will identify molecular differences in PTMs of collagen and osteocalcin between non- diabetic and diabetic bone in mice (model of type 2 diabetes) and in humans (cadaveric tissue from non-insulin dependent diabetics and non-diabetics). Specifically, using liquid chromatography and mass spectrometry, the relative abundance of modifications at individual sites will be quantified for enzyme-mediated hydroxylation and glycosylation of collagen I and carboxylation of osteocalcin and for non-enzymatic PTMs such as carboxymethyllysine and pentosidine, which have been associated with fracture risk. These PTMs potentially affect hydrogen bonding with water and/or the secondary structural organization of collagen. In Aim 2, we will determine whether 1H nuclear magnetic resonance (NMR), Raman spectroscopy (RS), and reference point indentation (RPI) can assess characteristics that differentiate non-diabetic from diabetic bone in mice and in humans. These techniques are chosen for their sensitivity to bound water within bone tissue matrix (NMR), to matrix maturity ratio (RS), and to mechanical consequence of diabetic changes to the matrix and possibly cortical porosity, respectively. Along with areal BMD, micro-computed tomography will be used to quantify volumetric bone and tissue mineral density as well as micro-structure of cortical bone. Mechanical testing will be used to quantify differences in several material properties of bone contributing to the diabetes-related difference in fracture resistance. With correlation analysis and general linear models, we will determine how well RS-, RPI- or NMR-derived values predict the type 2 diabetes-related decrease in the fracture resistance of bone. Moreover, we will determine whether PTMs can explain the possible changes in bound water and matrix maturity ratio in diabetes, thereby providing a potential underlying mechanism.

项目概要 随着糖尿病的进展，骨折的风险增加不仅仅是由于骨质减少 矿物质密度（BMD）。由于 2 型糖尿病患者的 BMD 看似正常甚至升高， 降低 2 型糖尿病患者的骨折风险需要了解骨组织的哪些方面 基质有助于增加骨折风险。在解决这个临床相关问题时，我们建议 i) 确定随着糖尿病进展导致骨脆性的骨组织基质的致病性变化 ii) 确定临床可转化诊断工具的效果（对基质和矿物质敏感） 骨）反映了与糖尿病相关的抗骨折能力的变化。我们假设 i) 的减少 骨基质内的结合水显着增加糖尿病骨的脆性，ii)a 基质结合水的减少是由于糖尿病引起的翻译后修饰的变化 (PTM) 位于骨基质内，以及 iii) 能够测量骨中结合水、骨的二级结构的工具 胶原蛋白和组织抗压痕性可用于评估糖尿病的抗骨折性。 在目标 1 中，我们将确定非非胶原蛋白和骨钙蛋白 PTM 的分子差异。 小鼠（2 型糖尿病模型）和人类（来自非胰岛素的尸体组织）的糖尿病和糖尿病骨 依赖糖尿病患者和非糖尿病患者）。具体来说，利用液相色谱和质谱分析， 各个位点修饰的相对丰度将被量化以用于酶介导的羟基化和 I 型胶原蛋白的糖基化和骨钙素的羧化以及非酶 PTM，例如 羧甲基赖氨酸和戊糖苷，它们与骨折风险相关。这些 PTM 可能 影响与水的氢键和/或胶原蛋白的二级结构组织。 在目标 2 中，我们将确定 1H 核磁共振 (NMR)、拉曼光谱 (RS)、 参考点压痕（RPI）可以评估区分非糖尿病和糖尿病的特征 小鼠和人类的骨骼。选择这些技术是因为它们对骨内结合水的敏感性 组织基质（NMR）、基质成熟度比（RS）以及糖尿病改变的机械后果 分别是基质和可能的皮质孔隙度。与面 BMD 一起，微型计算机断层扫描将 用于量化体积骨和组织矿物质密度以及皮质骨的微观结构。 机械测试将用于量化骨骼的几种材料特性的差异，这些差异有助于 糖尿病相关的抗骨折能力差异。通过相关分析和一般线性模型，我们将 确定 RS、RPI 或 NMR 导出值预测 2 型糖尿病相关的糖尿病相关降低的效果如何 骨的抗骨折能力。此外，我们将确定 PTM 是否可以解释可能的变化 糖尿病中的结合水和基质成熟度比率，从而提供了潜在的潜在机制。