Engineering Developmental Microenvironments: Cartilage Formation and Maturation

工程发育微环境：软骨的形成和成熟

• 批准号: 7653444
• 负责人: Jason A Burdick
• 金额: $ 34.4万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-13 至 2013-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7653444
• 关键词: 3-Dimensional; Adopted; Adult; Animals; Architecture; Autologous; Binding; Biocompatible Materials; Biomedical Engineering; Bioreactors; Cartilage; Cell Survival; Cells; Chemicals; Chondrocytes; Chondrogenesis; Complex; Coupled; Coupling; Cues; Data; Degenerative polyarthritis; Deposition; Development; Diffusion; Disease; Doctor of Philosophy; Embryo; Encapsulated; Engineering; Environment; Extracellular Matrix; Funding; Future; Gel; Gene Expression; Growth; Growth Factor; Healed; Hyaluronic Acid; Hydrogels; Hydrolysis; In Vitro; Incidence; Investigation; Joints; K22 Award; Laboratories; Lead; Mechanics; Mesenchymal Stem Cells; Methods; Modeling; Molecular; Motion; Orthopedic Surgery procedures; Orthopedics; Pathologist; Patients; Pattern; Physiological; Process; Production; Property; Publications; Research; Research Project Grants; Signal Transduction; Skeletal Development; Slide; Staging; Structure; Surface; Surgeon; System; Techniques; Testing; Tissue Engineering; Tissues; Trauma; Treatment Protocols; United States National Institutes of Health; Variant; Weight-Bearing state; Work; abstracting; articular cartilage; base; career; cartilage development; cartilage regeneration; clinically relevant; conditioning; crosslink; density; design; healing; implantation; in vivo; innovation; joint injury; novel; novel strategies; preconditioning; public health relevance; receptor; receptor binding; repaired; response; scaffold; subcutaneous

DESCRIPTION (provided by applicant): Articular cartilage lines the surfaces of joints and transmits the forces generated with loading. Due to limitations in cartilage's natural healing capacity, and given the increasing incidence of osteoarthritis, there exists a growing demand for cell-based strategies for repair. Tissue engineering, and particularly those approaches based on autologous mesenchymal stem cells (MSCs), is evolving as a clinically relevant technique to promote cartilage regeneration. Yet, the mechanics and ECM organization of engineered constructs for implantation have yet to match those of the native tissue and are insufficient to support joint loading. Most cartilage tissue engineering efforts replicate early stages of cartilage development, sequestering a high density of cartilaginous ECM producing cells in a defined volume. However, significant differences exist between these early rapid stages of cartilage formation and the gradual remodelling (maturation) that enables its adult function. With load-bearing use, cartilage ECM is wholly remodelled into the unique composition and architecture of the adult tissue. This transformative process is driven by a multitude of temporal factors (chemical, mechanical, and soluble). Our approach to cartilage tissue engineering adopts concepts of this complex developmental paradigm (from embryo to adult) with a synthetic hydrogel based on a natural ECM component, which provides initial receptor-matrix binding, controlled mechanics, and tailored degradation profiles. These gels, coupled with physiologic loading and temporal application of relevant soluble factors will re-create developmental microenvironments that both enable and encourage functional cartilage production by MSCs in 3-D culture. In the first Aim, MSCs will be encapsulated in HA hydrogels previously investigated as chondrocyte carriers with a range of structures that can influence cell viability, receptor-binding, diffusion, and ultimately, neocartilage properties and cultured under a range of conditions (i.e., cellular density and temporal variations in soluble factors). In the second Aim, novel HA hydrogels recently developed in our laboratory that degrade via both hydrolytic and enzymatic mechanisms will be investigated as 3D networks to promote MSC chondrogenesis and construct maturation. Temporal changes in degradation will be altered through the type of degradable group, crosslinking density, and copolymerization with HA macromers without hydrolytically degradable groups. In the third Aim, a mechanical loading bioreactor that applies sliding contact to hydrogel constructs will be applied to MSC-laden hydrogels identified in Aims 1 and 2, recapitulating normal physiologic loading patterns of cartilage. Mechanical preconditioning parameters will be evaluated in the short term (gene expression) and long term (matrix production, organization, and mechanics). These Aims were designed to allow the testing of our hypotheses that control over the MSC microenvironment and inclusion of signals present during normal development that are both permissive and instructive for cartilage formation and maturation will lead to final constructs with properties akin to native tissue. PUBLIC HEALTH RELEVANCE: This project develops a clinically-relevant approach to cartilage repair using MSC-laden hydrogels with temporally controlled structures subjected to physiologic mechanical conditioning to mimic the developmental paradigm of tissue formation and maturation that occurs from the embryo to adulthood. This biomaterial system provides receptor-matrix interactions, controlled mechanics, and tailored degradation profiles to enhance the differentiation of encapsulated MSCs and the accumulation and distribution of formed extracellular matrix (ECM). If successful, this approach would surmount a major hurdle in cartilage tissue engineering to provide a more structurally relevant ECM with enhanced mechanical properties to support the intense loads found in the joint. This cartilage tissue engineering technique could aid in the treatment of millions of patients afflicted with debilitating cartilage loss and degeneration due to trauma or disease.

描述（由申请人提供）：关节软骨排列在关节表面并传递负载时产生的力。由于软骨自然愈合能力的限制，以及骨关节炎发病率的增加，对基于细胞的修复策略的需求不断增长。组织工程，特别是基于自体间充质干细胞（MSC）的方法，正在发展成为一种促进软骨再生的临床相关技术。然而，用于植入的工程结构的力学和 ECM 组织尚未与天然组织相匹配，并且不足以支持关节负荷。大多数软骨组织工程工作复制了软骨发育的早期阶段，在一定体积内隔离高密度的软骨 ECM 产生细胞。然而，软骨形成的早期快速阶段和实现其成年功能的逐渐重塑（成熟）之间存在显着差异。通过承载使用，软骨 ECM 被完全重塑为成体组织的独特组成和结构。这一转变过程是由多种时间因素（化学、机械和可溶性）驱动的。我们的软骨组织工程方法采用了这种复杂的发育模式（从胚胎到成人）的概念，以及基于天然 ECM 成分的合成水凝胶，可提供初始受体-基质结合、受控力学和定制的降解曲线。这些凝胶与相关可溶性因子的生理负荷和时间应用相结合，将重新创建发育微环境，从而促进并鼓励 MSC 在 3D 培养中产生功能性软骨。在第一个目标中，间充质干细胞将被封装在HA水凝胶中，该水凝胶先前被研究为软骨细胞载体，具有一系列可以影响细胞活力、受体结合、扩散以及最终新软骨特性的结构，并在一系列条件下培养（即细胞可溶性因子的密度和时间变化）。在第二个目标中，我们实验室最近开发的新型 HA 水凝胶可通过水解和酶促机制降解，将作为 3D 网络进行研究，以促进 MSC 软骨形成和结构成熟。降解的时间变化将通过可降解基团的类型、交联密度以及与不含水解可降解基团的HA大分子的共聚来改变。在第三个目标中，将滑动接触应用于水凝胶结构的机械负载生物反应器将应用于目标 1 和 2 中确定的负载 MSC 的水凝胶，重现软骨的正常生理负载模式。将在短期（基因表达）和长期（基质产生、组织和力学）中评估机械预处理参数。这些目标旨在测试我们的假设，即控制 MSC 微环境，并纳入正常发育过程中存在的信号，这些信号对于软骨形成和成熟既是允许的又是指导性的，将导致最终的构建体具有类似于天然组织的特性。公共健康相关性：该项目开发了一种临床相关的软骨修复方法，使用含有间充质干细胞的水凝胶，该水凝胶具有受生理机械调节的时间控制结构，以模拟从胚胎到成年发生的组织形成和成熟的发育模式。该生物材料系统提供受体-基质相互作用、受控力学和定制的降解曲线，以增强封装的 MSC 的分化以及形成的细胞外基质 (ECM) 的积累和分布。如果成功，这种方法将克服软骨组织工程中的主要障碍，提供结构更相关的 ECM，具有增强的机械性能，以支撑关节中的强烈负载。这种软骨组织工程技术可以帮助治疗数百万因创伤或疾病而遭受软骨损失和退化的患者。