Advanced Glycation End Products Effects on Bone Biomechanics

描述(申请人提供)：将在小鼠模型中研究晚期糖基化终末产物(AGE)对皮质骨生物力学特性的影响。众所周知，AGE形成的交联会损害骨骼的生物力学特性。AGE随着年龄的增长而积累，也可以在某些疾病中发现，包括1型和2型糖尿病。该项目将采用独特的工具组合：生物力学测量、拉曼光谱和固态魔角旋转核磁共振波谱(MAS核磁共振)，将提供有关骨矿物微晶晶体结构和骨机械加载时胶原蛋白二级结构中材料特性变化的详细信息。一种定制设计的转子将用于弹性变形MAS核磁共振实验，其中包括施加压缩载荷的规定。外部加载将用于研究屈服点以外材料性质的化学结构相关性。我们假设，矿物质的变化将包括矿物质的压缩和基质胶原链的扭曲，因为交联键被扭曲，这些变化可以跟随骨骼的核磁共振和拉曼光谱的变化。核糖孵育将用于在小鼠皮质骨中产生AGE非酶交联物。孵化时间的变化将被用来改变交联链的丰度，并将为进一步研究提供背景信息。有了这一背景信息，将对年龄依赖性进行研究。我们假设矿物质压缩和胶原扭曲会随着年龄的增长而增加。接下来，我们将研究1型糖尿病小鼠模型NOD皮质骨的年龄效应。我们预计会看到与老龄化研究中的变化类似的变化，但它们将在更早的年龄开始。我们还将发展年龄水平和全骨特性之间的相关性，以及核磁共振产生的超微结构水平成分数据和全骨特性之间的相关性，为超微结构变化如何转化为全骨功能提供重要的见解，并作为骨骼脆性的预测因子。最后，我们将在MAS核磁共振提供的详细结构信息和拉曼光谱提供的不太详细的信息之间建立关联。这些相关性将被用来增加从其他拉曼光谱研究中获得的信息，特别是对骨骼疾病的非侵入性诊断。 公共卫生相关性：晚期糖基化终末产物随着年龄和包括1型和2型糖尿病在内的许多疾病的进展而积累。AGE会导致骨骼更脆弱，骨折风险更大，因此，重要的是准确了解AGE的运作方式，以便开发将损害降至最低的治疗方法和早期发现AGE存在的诊断方法。我们的项目将提供这些信息。

DESCRIPTION (provided by applicant): The effect of advanced glycation end products (AGE's) on the biomechanical properties of cortical bone will be studied in murine models. It is known that AGE's form cross-links that compromise bone biomechanical properties. AGE's accumlate with age and are also found in certain disorders, including type 1 and type 2- diabetes. The project will employ a unique combination of tools: biomechanical measurements, Raman spectroscopy and solid state magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) that will provide detailed information on material property changes in the crystal structure of bone mineral crystallites and in the collagen secondary structure as the bone is mechanically loaded. A custom-designed rotor that includes provision for applying compressive load will be used for elastic deformation MAS NMR experiments. External loading will be used to study chemical structure correlates of material properties beyond the yield point. We hypothesize that changes in the mineral will include mineral compression and distortion of the matrix collagen chain as cross-links are distorted and that these changes can be followed as changes in both NMR and Raman spectra of the bone. Ribose incubation will be used to generate AGE non-enzymatic cross-links in murine cortical bone. Variations in incubation time will be used to vary the cross-link abundance and will provide background information for further studies. With this background information, a study of age- dependence will be undertaken. We hypothesize that mineral compression and collagen distortion will increase with age. Next, we will study the AGE effects in NOD cortical bone, a mouse model for type 1 diabetes. We expect to see changes similar to those in the aging study, but that they will begin at earlier ages. We will also develop correlations between AGE levels and whole bone properties and between ultrastructural level composition data generated by NMR and whole bone properties, providing important insights into how ultrastructural changes translate into whole bone function and serve as predictors of skeletal fragility. Finally, we will develop correlations between the detailed structural information provided by MAS NMR and the less detailed information provided by Raman spectroscopy. These correlations will be used to increase the information gained from other Raman spectroscopic studies, especially non-invasive diagnostics for bone disorders. PUBLIC HEALTH RELEVANCE: Advanced glycation end products accumulate with age and with progression of many disorders including type 1 and type 2-diabetes. AGE's lead to weaker bones and greater fracture risk, so it is important to understand exactly how AGE's operate in order to develop treatments that minimize the damage and diagnostic methods for early detection of their presence. Our project will provide this information.