An Evaluation of Serum Based Indices to Assess Fracture Healing

摘要 骨折是人类最常见的大器官、创伤和骨质疏松相关的骨折。 老龄化是增长最快的医疗保健问题。虽然手术后的骨折修复通常是最佳的，但 据估计，在美国每年发生的约800万至1000万起骨折中，有10%至10%的人 愈合延迟或受损(Praemer等人，1992)。目前，放射学评估，减少了 痊愈并发症和患者报告的无痛负重和恢复的结果 功能是评估骨折愈合进程的主要诊断工具。然而，这些都不是 目前的评估要么定义了与疾病进展相关的潜在生物学过程 骨折愈合，或者它们预示着延迟愈合或骨不连。因此，有一个巨大的和 迫切需要确定客观的可量化的生物标记：1)与潜在的生物标记有关的标记 骨组织愈合过程：2)指示骨组织愈合进程的过程：3) 将预示着骨骼组织愈合的缺陷。这种化验方法的发展将是一个 极大的好处：1)提供有关延迟愈合和失败愈合的潜在原因的信息；2)在临床上使用 评估促进骨愈合的生物或药物疗法的疗效的试验：3) 确定哪些患者将从生物或药物治疗干预中受益 促进骨愈合。我们的假设是，将会有一组血清标志物可以用来 定义骨折愈合的生物学进程，我们将能够将其中的一个或多个联系起来 确定愈合进程的结构、功能和临床特征的标记物。两个具体的 提出了目标。目标1将确定血清蛋白质组中那些显示变化的水平的蛋白质 相对于未骨折的骨，在骨折愈合的时间进程中的表达。在这一目标中，有两个方法 将使用：质谱学方法和更有针对性的基于适体的新型多路蛋白质组 技术这一目标是为了识别和提供可以被 与定义骨折愈合的时间进程的各种生物过程有关。在目标2中，我们 将测试这些蛋白质的子集，以确定它们与软骨发育和吸收的统计相关性， 软骨决定骨和骨痂组织矿化的发育和重塑 增强对比度和标准µCT。我们将测试特定蛋白质表达的统计相关性 特定的生物力学功能(硬度、强度、功到失效)。最后，我们将测试愈伤组织结构， 功能测量和特定蛋白标记物与当前临床使用的放射学骨折愈合相关 胫骨(锈迹)骨折愈合评分(Whelan等人，2010)，用于评估人类的进展 长骨愈合。如果成功，这项研究将确定一组可用于人体试验的蛋白质 用于跟踪骨折愈合的诊断效果以及对延迟或失败愈合的预后效果。

ABSTRACT Fractures are the most common large-organ, traumatic injuries in humans, and osteoporosis-related fractures are the fastest growing health care problem of aging. While fracture repair after surgery is usually optimal, up to 10% percent of the estimated ~8 to 10 million fractures that occur annually in the United States show delayed or impaired healing (Praemer et al., 1992). Currently, radiographic assessment, with reduction in healing complication and validated patient reported outcomes of regain of pain free weight bearing and function are the primary diagnostic tools to assess the progression of fracture healing. However none of these current assessments either define underlying biological processes that are related to the progression of fracture healing or are they prognostic for delayed healing or non-unions. Thus, there is an immense and immediate need to identify objective quantifiable biological markers: 1) that relate to the underlying biological processes of skeletal tissue healing: 2) that are indicative of the progression of skeletal tissue healing:3) that would be prognostic of deficiencies in skeletal tissue healing. The development of such an assay would be an immense benefit to: 1) be informative to the underlying causes for delayed and failed healing: 2) use in clinical trials that assess the efficacy of biological or pharmacological therapies that promote bone healing and: 3) identify those patients that would benefit from biological or pharmacological therapeutic interventions to promote bone healing. Our hypothesis is that there will be a combination of serum markers that can be used to define the biological progression of fracture healing and that we will be able to relate one or more of these markers to structural, functional and clinical characteristics that define the progression of healing. Two specific aims are proposed. Aim 1 will identify those proteins in the serum proteome that show changed levels of expression across the time course of fracture healing relative to unfractured bone. In this aim, two approaches will be used: a mass spectrometry approach and a more targeted novel aptamer-based multiplexed proteomic technology. This aim is will identify and provide preliminary quantification of a subset of proteins that can be related to various biological processes that define the temporal progression of fracture healing. In Aim 2, we will test a subset of these proteins for their statistical correlation to the development and resorption of cartilage, development and remodeling of bone and callus tissue structure mineralization as determined by both cartilage contrast enhanced and standard µCT. We will test for statistical correlation of specific protein expression to specific biomechanical functions (stiffness, strength, work to failure). Finally, we will test how callus structure, function measurements and specific protein markers correlate to current clinically used Radiographic Union Score for Tibial (RUST) fracture healing (Whelan et al., 2010) that is used to assess the progression of human long bone healing. If successful this study will identify a set of proteins that can be used in a human trial to test for their diagnostic efficacy to follow fracture healing and their prognostic efficacy for delayed or failed healing.