A Bio-inspired Latent TGF-beta Conjugated Scaffold for Patient-specific Cartilage Regeneration

用于患者特异性软骨再生的仿生潜在 TGF-β 共轭支架

• 批准号: 10631889
• 负责人: Michael B Albro
• 金额: $ 43.77万
• 依托单位: BOSTON UNIVERSITY (CHARLES RIVER CAMPUS)
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10631889
• 关键词: Acceleration; Anabolism; Animals; Autologous; Autologous Transplantation; Binding; Bioreactors; Cartilage; Cell Fraction; Cell physiology; Cells; Cellular Morphology; Chondrocytes; Clinical; Defect; Degenerative polyarthritis; Development; Diffuse; Diffusion; Dose; Encapsulated; Engineering; Environment; Enzymes; Equilibrium; Exhibits; Exposure to; Extracellular Matrix; Failure; Family suidae; Fibrocartilages; Fibrosis; Generations; Growth; Growth Factor; Health; Human; Hyaline Cartilage; Hyperplasia; Hypertrophy; Implant; In Situ; In Vitro; Integrins; Kinetics; Mechanics; Mediator; Methods; Modeling; Molecular; Morphology; Outcome; Pathogenicity; Pathologic; Pathology; Patients; Penetration; Performance; Phase; Phenotype; Physiological; Population; Process; Protocols documentation; Reaction; Regenerative Medicine; Residual state; Series; Site; Source; Stress; Supplementation; Synovial joint; Synovitis; System; Time; Tissue Engineering; Tissue Grafts; Tissue constructs; Tissues; Transforming Growth Factor beta; Transplantation; articular cartilage; bioscaffold; cartilage development; cartilage regeneration; cartilage repair; cartilaginous; chemical reaction; design; efficacy evaluation; expectation; experimental study; hydrogel scaffold; implantation; improved; in vivo; individual patient; innovation; mechanical properties; novel; osteochondral tissue; predictive modeling; repaired; scaffold; success; tissue repair; treatment strategy

Summary Transforming growth factor beta (TGF-) has become one of the most widely utilized mediators to promote cartilage growth in tissue engineering (TE) applications. Conventionally, for in vitro culture phases, TGF- is supplemented in the culture medium with the expectation that it will readily diffuse into tissues and promote the biosynthesis of a healthy cartilage ECM. However, a growing body of evidence brings to light a central paradox with this conventional TGF- delivery strategy: physiologic TGF- doses exhibit limited penetration into the tissue, giving rise to undesirable non-uniform growth, while the alternative use of higher, supraphysiologic TGF- doses promotes the formation of cartilage with compromised tissue quality (e.g., fibrosis, hypertrophy, hyperplasia). In contrast to conventional TE TGF- delivery strategies, the natural process of TGF- delivery in native cartilage occurs quite differently, where chondrocytes are surrounded by large stores of TGF- that are sequestered in an inactive form, termed latent TGF- (LTGF-). Chondrocytes activate LTGF- stores via integrins or secreted enzymes, leading to highly advantageous, need-based activity throughout the tissue, which allows for essential ECM biosynthesis while avoiding the induction of pathological tissue formation. This proposal capitalizes on this native regulatory mechanism by creating a bio-inspired TE strategy, whereby chondrogenic cells are encapsulated in a hydrogel scaffold conjugated with large stores of LTGF-, akin to the native environment. This platform allows cells to endogenously activate these LTGF- stores, giving rise to the highly beneficial delivery of uniform and moderated, near-physiologic TGF- doses to cells, which promote biosynthetic enhancements in the absence of tissue quality limitations. Further, a novel reaction-diffusion modeling framework is developed to predict the activity of TGF- exposed to cells in constructs while accounting for the critical patient-specific chemical reactions applied to TGF- in the tissue. These patient-specific models can guide optimal LTGF- design parameters, allowing for optimal activity doses and giving rise to improved TE cartilage quality and mitigation of pathogenic off-target desorption of TGF- from the construct. In the current project, we examine the efficacy of this bio-inspired LTGF- scaffold platform by assessing: 1) the capability of reaction-diffusion models to optimize growth outcomes in patient-specific cell populations (human chondrocytes and MSCs), 2) the capability of model-optimized LTGF- scaffolds to improve TE cartilage performance in the hostile mechanochemical environment of the OA synovial joint through use of an ex vivo synovial joint bioreactor, and 3) the capability of LTGF- scaffolds to improve TE cartilage performance in an in vivo porcine focal defect model.

概括 转化生长因子β（TGF-β）已成为最广泛使用的促进介质之一 组织工程（TE）应用中的软骨生长。传统上，对于体外培养阶段，TGF-β是 在培养基中补充，期望它很容易扩散到组织中并促进 健康软骨 ECM 的生物合成。然而，越来越多的证据揭示了一个核心问题 这种传统 TGF-β 递送策略的悖论：生理 TGF-β 剂量的渗透性有限 进入组织，导致不良的不均匀生长，而替代使用更高的， 超生理学 TGF-β 剂量会促进软骨的形成，但组织质量会受损（例如， 纤维化、肥大、增生）。与传统的 TE TGF-β 递送策略相比，自然 TGF-β 在天然软骨中的传递过程发生完全不同，其中软骨细胞被 大量 TGF-β 以非活性形式被隔离，称为潜在 TGF-β (LTGF-β)。软骨细胞 通过整合素或分泌酶激活 LTGF- 储存，从而产生高度有利的、基于需求的 整个组织的活性，这允许必要的 ECM 生物合成，同时避免诱导 病理组织形成。 该提案通过创建仿生 TE 策略来利用这种本地监管机制， 软骨形成细胞被封装在与大量 LTGF-β 结合的水凝胶支架中， 类似于原生环境。该平台允许细胞内源性激活这些 LTGF- 库， 产生高度有益的均匀、适度、接近生理的 TGF-β 剂量递送至细胞， 在没有组织质量限制的情况下促进生物合成的增强。 此外，开发了一种新的反应扩散模型框架来预测 TGF-β 的活性 暴露于构建体中的细胞，同时考虑到应用于关键的患者特异性化学反应 组织中的 TGF-β。这些针对患者的模型可以指导最佳的 LTGF- 设计参数，从而允许 最佳活动剂量，提高 TE 软骨质量并减轻致病性脱靶 TGF-β 从构建体中解吸。 在当前的项目中，我们通过评估以下方面来检查这种仿生 LTGF- 支架平台的功效： 1) 反应扩散模型优化患者特定细胞群生长结果的能力 （人软骨细胞和 MSC），2) 模型优化的 LTGF- 支架改善 TE 的能力 通过使用骨关节炎滑膜关节的恶劣机械化学环境中的软骨性能 离体滑膜关节生物反应器，以及 3) LTGF- 支架改善 TE 软骨性能的能力 在体内猪局灶性缺陷模型中。