Bone Water & Mineralization: Nuclear Magnetic Resonance

骨水

• 批准号: 6941298
• 负责人: Felix W Wehrli
• 金额: $ 30.26万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-09 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6941298
• 关键词: bone density; bone development; bone imaging /visualization /scanning; laboratory rabbit; laboratory rat; mathematical model; normal ossification; nuclear magnetic resonance spectroscopy; osteocytes; osteoporosis; photon absorptiometry; substantia spongiosa

DESCRIPTION (provided by applicant): The mechanical competence of bone is determined by the amount of bone per unit volume (also referred to as apparent density), its structural arrangement and its chemical make-up. Age and osteoporosis-related deterioration of the bone has typically been attributed to a net loss of bone mass and architectural impairment but it has been widely assumed that the bone's intrinsic material properties remain invariant. This notion is in conflict with a substantial body of literature indicating significant decreases in the degree of mineralization of bone (DMB) following ovariectomy and increased DMB in response to antiresorptive treatment. Such a behavior is plausible since the bone turnover rate determines the average age of the bone and younger bone is known to be hypomineralized. Paralleling changes in DMB are the bone's biomechanical properties in that decreased DMB is associated with decreased static strength and Young's modulus. The extent to which mechanical failure in the form of fractures is related to changes in the bone's mineral content is not known. Unfortunately, DMB cannot currently be measured noninvasively. However, since DMB is related to the bone's osteoid water content, information on mineral density can be obtained indirectly. There is evidence that during mineralization some of the matrix water is displaced and its space taken by mineral in such a manner that osteoid volume remains constant. In this proposal we advance the hypothesis that there is an inverse relationship between osteoid water and bone mineral volume and that a measure of DMB can be obtained indirectly by quantitative proton magnetic resonance of solid bone. We provide evidence in preliminary work that decreased mineralization is associated with higher water content and that the matrix water can be imaged with appropriate imaging techniques in intact bone. In two disease models in which DMB is expected to be altered (rabbit osteomalacia and rat ovariectomy) we test the hypothesis using proton and 31P NMR that changes in DMB occur at the expense of a commensurate change in bone water and further that increased bone water decreases static strength and elastic modulus. The long-term goal of this project is to provide a noninvasive method for probing the intrinsic properties of bone in laboratory animals and ultimately in humans.

描述（由申请人提供）： 骨的机械能力由每单位体积的骨的量（也称为表观密度）、其结构排列和其化学组成决定。年龄和骨质疏松相关的骨退化通常归因于骨量的净损失和结构损伤，但人们普遍认为骨的内在材料特性保持不变。这一观点与大量文献相矛盾，这些文献表明卵巢切除术后骨矿化程度（DMB）显著降低，抗吸收治疗后DMB增加。这种行为是合理的，因为骨转换率决定了骨的平均年龄，并且已知较年轻的骨矿化不足。DMB的显著变化是骨的生物力学性质，因为DMB的降低与静态强度和杨氏模量的降低相关。骨折形式的机械故障与骨矿物质含量变化的相关程度尚不清楚。不幸的是，DMB目前无法无创测量。然而，由于DMB与骨的类骨质水含量有关，因此可以间接获得有关矿物质密度的信息。有证据表明，在矿化过程中，一些基质水被置换，其空间被矿物质占据，使得类骨质体积保持恒定。在这个建议中，我们提出的假设，有一个成反比的关系，类骨质水和骨矿物质的体积和DMB的措施，可以间接获得定量质子磁共振固体骨。我们在初步工作中提供的证据表明，矿化减少与较高的含水量有关，基质水可以在完整骨中用适当的成像技术成像。在两种疾病模型，其中DMB预计将被改变（兔骨软化症和大鼠卵巢切除术），我们测试的假设，使用质子和31 P NMR，DMB的变化发生在骨水的相应变化的代价，并进一步增加骨水降低静态强度和弹性模量。该项目的长期目标是提供一种非侵入性的方法，用于探测实验室动物和最终人类骨骼的内在特性。