Bioactive Scaffold for TMJ Disc Regeneration by Endogenous Stem/Progenitor Cells

项目总结 据NIDCR估计，颞下颌关节紊乱病(TMJDS)影响着1000多万美国人。 总共有80%-90%的症状性TMJDS患者有内部排列紊乱(ID)，也称为椎间盘 移位，这与骨关节炎(OA)高度相关，可能需要手术治疗。 以前用同种异体和/或合成移植物替换TMJ盘的尝试都失败了，导致进一步 关节退化。因此，最近出现了TMJ盘的再生，作为克服 目前治疗TMJ障碍的局限性。在我们之前的研究中，我们发现了解剖学上的正确性。 3D打印的聚己内酯(PCL)支架具有天然的各向异性微纤维取向。要设计 类天然异质纤维软骨，结缔组织生长因子(CTGF；促纤维化线索)和 将转化生长因子β3(转化生长因子β3；软骨生成线索)以空间方式嵌入支架中 聚乳酸-羟基乙酸共聚微球(PLGA)(μS)。结缔组织生长因子的时空释放 和转化生长因子β-3引导的TMJ-syMSCs的募集，随后空间控制的纤维软骨分化 兔和小型猪TMJ的再生。尽管体内结果很有希望，但我们的CTGF/转化生长因子β3 μS嵌入的支架在颞下颌关节盘再生方面遇到的翻译挑战很少， 包括PLGA降解衍生的酸性环境，体内显著的物种间差异 支架的降解率，以及过度生理剂量的生长因子的潜在副作用。致信地址 这些问题，我们在这里建议开发和验证一种新型的药物小分子组合 取代CTGF和转化生长因子β3作为生物活性支架材料，将体内降解率细化为 通过我们先进的成像方式与新生组织形成保持平衡，然后促进 临床前大型动物模型中TMJ盘的再生。我们的初步研究确定了小说Small 安全、高效、特异促进TMJ纤维软骨分化的分子- 来源的间充质干细胞。我们还实现了对3D打印TMJ光盘中小分子的精确控制输送 采用自组装多结构域多肽(MDP)水凝胶作为载体构建支架。我们也 设计了一种高效和可靠的成像方式，能够跟踪体内支架的降解和 新的组织形成。我们将对小分子和小分子进行全面的比较研究 细胞生长因子/转化生长因子β-3作为对照，在我们的支架中传递，研究局部/组织的pH变化，细胞毒性，降解 并在我们的TMJ椎间盘工程模型中进行体外组织形成。我们将进行一项全面的体内研究 平衡支架降解和组织再生。降解率将通过施药控制 表面微孔，体内跟踪支架的降解以及纤维软骨的再生 通过我们的微创成像设备实现。

Project summary Temporomandibular joint disorders (TMJDs) are estimated to affect over 10 million Americans as per NIDCR. Total 80 - 90% of symptomatic TMJDs patients have internal derangement (ID), also referred to as disc displacement, which is highly associated with osteoarthritis (OA) that may necessitate surgical treatment. Previous attempts to replace the TMJ disc with alloplastic and/or synthetic grafts have failed, resulting in further joint degradation. Thus, regeneration of TMJ disc has recently emerged as an alternative approach to overcome limitations of current treatments for TMJ disorders. In our preceding studies, we developed anatomically correct 3D-printed polycaprolactone (PCL) scaffolds with native-like anisotropic microfiber orientation. To engineer the native-like heterogeneous fibrocartilage, connective tissue growth factor (CTGF; profibrogenic cue) and transforming growth factor beta 3 (TGFβ3; chondrogenic cue) were spatially embedded in the scaffolds as encapsulated in poly(lactic-co-glycolic acids) (PLGA) microspheres (μS). The spatiotemporal release of CTGF and TGFβ3 guided recruitment of TMJ syMSCs, followed by spatially controlled fibrocartilaginous differentiation toward regeneration of TMJ in rabbits and mini-pigs. Despite the promising in vivo outcome, our CTGF/TGFβ3 μS-embedded scaffolds encountered few outstanding translational challenges for TMJ discs regeneration, including PLGA degradation-derived acidic environment, a notable interspecies variance in the in vivo degradation rate of scaffolds, and potential side effect of over-physiological dose of growth factor. To address these issues, here we propose to develop and validate a novel combination of pharmaceutical small molecules to replace CTGF and TGFβ3 as incorporated in bioactive scaffolds, to refine the in vivo degradation rate as balanced with de novo tissue formation through our advanced imaging modality, and then to promote regeneration of TMJ discs in a pre-clinical large animal model. Our preliminary study identified novel small molecules that are safe and highly efficient and specific for promoting fibrocartilaginous differentiation of TMJ- derived syMSCs. We also achieved a precisely controlled delivery of the small molecules in 3D-printed TMJ disc scaffolds by adopting a self-assembling multi-domain peptide (MDP) hydrogel as a delivery vehicle. We also devised a highly efficient and reliable imaging modality that will enable to track in vivo scaffold degradation and new tissue formation. We will perform a comprehensive comparative study between small molecules and CTGF/TGFβ3 as control-delivered in our scaffolds regarding local/tissue pH change, cytotoxicity, degradation and tissue formation in our TMJ disc engineering model in vitro. We will conduct a comprehensive in vivo study to balance scaffold degradation with tissue regeneration. The degradation rate will be controlled by applying surface micro-porosity, and in vivo tracking of scaffold degradation as well as fibrocartilage regeneration will be achieved via our minimally invasive imaging modality.