Selection of Therapeutic Agents for Articular Cartilage Repair

描述（由申请人提供）： 关节软骨是关节的滑动面。关节软骨的损失，通过创伤或骨关节炎，是疼痛和残疾的主要原因。目前的治疗方法解决了软骨损失引起的症状。需要治疗，纠正软骨损失本身。理论上，实现这一点的一种方法是用细胞调节分子如成纤维细胞生长因子-2（FGF-2）和胰岛素样生长因子-I（IGF-I）刺激软骨细胞。第二种方法是使用软骨结构分子，如胶原蛋白和聚集蛋白聚糖，用它们来构建新的软骨。目前还不知道这些替代方法如何相互比较，或者它们是否可以合并。本建议旨在回答这些问题。这些研究将在软骨修复的离体模型中采用基于细胞的基因治疗来测试以下假设。目标1：确定成纤维细胞生长因子-2（FGF-2）的基因治疗是否可以诱导促进修复的活性，而不会诱导促进损伤的活性。 假设1A：过表达的FGF-2的修复促进和损伤促进作用由特定的FGF-2同种型选择性介导，因此特定的FGF-2同种型将优先增加新的软骨形成。 假设1B：FGF-2亚型的作用机制涉及亚型的不同亚细胞定位。目的2：确定使用基质基因的基因治疗是否增强关节软骨修复。 假设2A：II型胶原蛋白或聚集蛋白聚糖的过度表达增加新的软骨形成。 假设2B：II型胶原和聚集蛋白聚糖两者的过表达在产生新的软骨形成方面优于单独的任一者的过表达。目标三：确定在改善关节软骨修复方面，生长因子基因和基质基因联合使用的基因治疗是否优于单独使用任何一类药物的基因治疗上级。 假设3A：选择的FGF-2同种型和IGF-I基因与胶原蛋白和聚集蛋白聚糖基质基因一起递送比单独的任一类试剂更大程度地增加新软骨形成假设3B：人关节软骨细胞以类似于牛关节软骨细胞的方式对基因转移作出反应。将使用组织学、生物化学和分子生物学参数评估修复。这些研究的长期目标是选择适合临床应用的软骨修复基因治疗剂。 公共卫生相关性： 项目叙述和退伍军人健康的相关性关节软骨损失是美国退伍军人的一个未解决的问题。它影响年轻的退伍军人谁遭受创伤和老年退伍军人谁发展关节炎。退伍军人管理局国家患者护理数据库1999财政年度确定了超过260，000名患有骨关节炎的退伍军人（Jones A等人，2005）。尽管有大量不同的治疗方法用于治疗软骨损伤，但问题越来越严重。据估计，由于目前治疗缺乏疗效，到2030年，仅膝关节将有85%的关节置换术（Mamlin LA等，1998）。目前的治疗方法能够减少软骨损失引起的症状，但缺乏可以纠正软骨损失本身的治疗方法。该研究项目旨在确定哪些潜在的治疗药物是关节软骨基因治疗的良好候选者。

DESCRIPTION (provided by applicant): Articular cartilage is the gliding surface of diarthrodial joints. The loss of articular cartilage, through trauma or osteoarthritis, is a major cause of pain and disability. Current treatments address the symptoms that result from cartilage loss. Treatments are needed that correct the cartilage loss itself. One approach to accomplishing this is, in theory, to stimulate the cartilage cells with cell-regulatory molecules such as fibroblast growth factor-2 (FGF-2) and insulin-like growth factor-I (IGF-I). A second approach is to employ cartilage structural molecules, such as collagen and aggrecan, with which to build new cartilage. It is not known how these alternative approaches compare with each other, or whether they can be combined. This proposal seeks to answer these questions. The studies will employ cell-based gene therapy in an ex vivo model of cartilage repair to test the following hypotheses. Objective 1: Determine whether gene therapy with fibroblast growth factor-2 (FGF-2) can induce repair-promoting activity without also inducing damage-promoting activity. Hypothesis 1A: The repair-promoting and damage-promoting actions of overexpressed FGF-2 are selectively mediated by specific FGF-2 isoforms and therefore specific FGF-2 isoforms will preferentially augment new cartilage formation. Hypothesis 1B: The mechanism of FGF-2 isoform action involves differential subcellular localization of the isoforms. Objective 2: Determine whether gene therapy using matrix genes augments articular cartilage repair. Hypothesis 2A: Overexpression of type II collagen or of aggrecan increases new cartilage formation. Hypothesis 2B: Overexpression of both type II collagen and aggrecan is superior to overexpression of either alone in generating new cartilage formation. Objective 3: Determine whether gene therapy with growth factor genes and matrix genes in concert is superior to gene therapy employing either class of agent alone in improving articular cartilage repair. Hypothesis 3A: Delivery of selected FGF-2 isoform and IGF-I genes together with collagen and aggrecan matrix genes increases new cartilage formation to a greater degree than either class of agent alone Hypothesis 3B: Human articular chondrocytes respond to gene transfer in a fashion similar to that of bovine articular chondrocytes. Repair will be assessed using histological, biochemical, and molecular biological parameters. The long-term goal of these studies is to select gene therapy agents for cartilage repair that are suitable for clinical application. PUBLIC HEALTH RELEVANCE: Project Narrative and Relevance to Veterans' Health Articular cartilage loss is an unsolved problem for American veterans. It affects young veterans who have sustained trauma and aging veterans who develop arthritis. The Veterans Administration National Patient Care Database for fiscal year 1999 identified over 260,000 veterans with osteoarthritis (Jones A et al, 2005). Despite the large and diverse number of therapeutic options being used to treat cartilage damage, the problem is getting worse. It has been estimated that, for knee joints alone, there will be an 85% in joint replacements by 2030 due to the lack of efficacy of current treatments (Mamlin LA et al, 1998). Current therapies are able to decrease the symptoms that result from cartilage loss, but treatments are lacking that can correct the cartilage loss itself. This research project is designed to determine which potential therapeutic agents are good candidates for articular cartilage gene therapy.