Scaffold for Soft Tissue to Bone Integration

描述（由申请人提供）：前交叉韧带（ACL）是最常见的膝关节韧带损伤，在美国每年进行约75，000例韧带手术。自体骨-髌腱-骨移植物和腘绳肌腱移植物是ACL重建手术中最常用的移植物。在术后早期愈合阶段，骨隧道中的移植物接触部位是机械上最薄弱的部位。因此，ACL重建手术的临床成功取决于移植物固定和骨与软组织之间功能界面的形成。 原生ACL-骨附着区由四个不同区域组成：韧带、非矿化纤维软骨、矿化纤维软骨和骨。我们的方法工程的功能接口是通过新的共培养成骨细胞和韧带成纤维细胞的多相支架系统与梯度的结构和功能特性，模仿那些本地插入区。之所以选择这些设计参数，是因为在整个插入区都观察到多种类型的细胞和矿物质含量的固有增加。我们的假设是，成骨细胞和韧带成纤维细胞在具有仿生磷酸钙（Ca-P）组合物的多相支架上的共培养将导致支架中纤维软骨样界面区的形成。为了检验这一假设，本提案的具体目标是： 目标1。表征自体ACL-骨界面的矿物质含量（Ca-P分布、Ca/P比）。 目标2.开发具有Ca-P仿生成分变化的多相支架，并检查成骨细胞-韧带成纤维细胞共培养物对该支架上界面区特异性标记物（蛋白聚糖，II型和X型胶原）形成的影响。 我们的方法的全局假设是，天然组织中的组成和结构分布与功能相关。ACL-骨界面的拟议评价将提供以前无法获得的对插入区组织特征的深入了解，并确定具有受控不均匀性的支架的设计目标。通过将成骨细胞-成纤维细胞共培养和适当的矿物质含量的区域依赖性变化实施到多相支架的设计中，我们试图为开发能够促进愈合并促进体内软组织移植和骨整合的功能仿生支架奠定基础。

DESCRIPTION (provided by applicant): The anterior cruciate ligament (ACL) is the most frequently injured knee ligament, with approximately 75,000 ligament surgeries performed annually in the United States. The autologous bone-patellar tendon- bone graft and the hamstring tendon graft are the most commonly utilized grafts for ACL reconstruction surgeries. In the early post-operative healing period, the site of graft contact in the bone tunnels represents the weakest point mechanically. Therefore, the clinical success of ACL reconstructive surgeries depends on graft fixation and the formation of a functional interface between bone and soft tissue. The native ACL-bone insertion zone is comprised of four different regions: ligament, non-mineralized fibrocartilage, mineralized fibrocartilage, and bone. Our approach to engineering a functional interface is through the novel co-culture of osteoblasts and ligament fibroblasts on a multi-phased scaffold system with a gradient of structural and functional properties that mimic those of the native insertion zones. These design parameters are chosen because multiple types of cells and an inherent increase in mineral content are both observed across the insertion zone. Our hypothesis is that the co-culture of osteoblasts and ligament fibroblasts on a multi-phased scaffold with a biomimetic calcium phosphate (Ca-P) composition will result in the formation of a fibrocartilage-like interracial zone in the scaffold. To test this hypothesis, the specific aims of this proposal are: Aim 1. To characterize the mineral content (Ca-P distribution, Ca/P ratio) across the native ACL-bone interface. Aim 2. To develop a multi-phased scaffold with a biomimetic compositional variation of Ca-P and to examine the effects of osteoblast-ligament fibroblast co-culture on the development of interfacial zone specific markers (proteoglycan, types II & X collagen) on this scaffold. The global hypothesis of our approach is that the compositional and structural distributions in the native tissue are correlated with functionality. The proposed evaluation of the ACL-bone interface will provide previously unavailable insight into the organizational characteristics at the insertion zone, and identify design objectives for scaffolds with controlled inhomogeneity. By implementing both osteoblast- fibroblast co-culture and the appropriate zonal dependent variations in mineral content into the design of multi-phased scaffolds, we seek to lay the foundation for the development of functional biomimetic scaffolds which can promote healing and facilitate soft tissue graft and bone integration in vivo.