PRECLINICAL EVALUATION OF NANOPARTICULATE MINERALIZED COLLAGEN GLYCOSAMINOGLYCAN MATERIALS IN CALVARIAL REGENERATION

项目摘要/摘要 颅骨的缺陷经常发生在创伤、中风、癌症和先天性畸形中，导致 严重的神经、心理、社会和职业负担。当前临床选择的局限性 用于颅骨缺损重建，如自体骨和自体骨中组织可用性和供区发病率 异形材料的挤出、感染和成本，提供了开发特定方法的动力 以颅骨再生为目标。尽管进行了数十年的研究，当代的再生战略 由支架材料提供的由扩增的干细胞和生长因子组成的鸡尾酒没有 由于手术不切实际、成本、时间消耗和 生长因子超生理剂量的不良反应。随着人们对这一问题的了解不断增加 细胞外基质的指导性功能，我们以前证明了细胞外基质的功效 纳米粒矿化胶原糖胺聚糖(MC-GAG)组成的基质诱导材料 无体外扩增祖细胞或外源性生长因子的颅骨大段缺损的再生 补充。进一步揭示了MC-GAG诱导成骨分化的机制。 是由于骨形态发生蛋白受体(BMPR)信号通路的自激活。 我们以前的工作建立了MC-GAG的概念，作为一种仅限材料的再生策略。然而， 有三个问题需要进一步调查。首先，MC-GAG有哪些特性可以诱导 成骨和它们能被提炼吗？其次，使用MC-是否有任何不良副作用- 恶作剧？第三，由于大脑保护在临床相关的缺陷中是最重要的，而再生并不能提供 保护直到治疗完成，MC-GAG是否会表现出与 与临床可用的可吸收材料的复合材料用于脑保护？在目标1中，我们将确定 钙和磷诱导的信号转导和机械硬度在MC-GAG介导中的作用 人骨髓间充质干细胞的成骨作用。我们假设钙和磷离子信号 可能是MC-GAG成骨分化的主要触发因素，连接了 材料、自体BMPR信号、基质矿化和骨愈合。在目标2中，我们将评估一个 MC-GAG与聚D，L-丙交酯网片复合的临床可吸收颅骨成形术 材料，在兔颅骨缺损模型中进行生物力学特性、血管、炎症、骨 治愈，以及局部和全身安全。我们假设MC-GAG/PDLLA复合材料会产生骨 再生相当于单独使用MC-GAG，并在再生过程中增加了脑保护的维度。 我们建议的研究统一在颅骨再生技术开发的目标上。海流 该提案将使我们能够了解MC-GAG和祖细胞之间的机制相互作用，以进一步 改进材料，并为向FDA提交的IDE应用程序生成临床前安全性和性能数据。

PROJECT SUMMARY/ABSTRACT Defects of the cranial skeleton occur frequently in trauma, stroke, cancer, and congenital anomalies resulting in significant neurological, psychological, social, and vocational burdens. The limitations of current clinical options for cranial defect reconstruction, such as tissue availability and donor site morbidity in autologous bone and extrusion, infection, and cost in alloplastic materials, provide an impetus to develop methods that specifically target calvarial bone regeneration. Despite decades of research, contemporary regenerative strategies consisting of expanded stem cells and growth factor cocktails delivered by scaffolding materials have not attained clinical translation secondary to the drawbacks of surgical impracticality, cost, time consumption, and the untoward effects of supraphysiologic dosages of growth factors. With the increasing knowledge of the instructive capabilities of the extracellular matrix, we previously demonstrated the efficacy of an extracellular matrix-inspired material composed of nanoparticulate mineralized collagen glycosaminoglycan (MC-GAG) for regeneration of massive calvarial defects without ex vivo progenitor cell expansion or exogenous growth factor supplementation. We further showed that the mechanistic basis for MC-GAG induced osteogenic differentiation was due to an autogenous activation of the bone morphogenetic protein receptor (BMPR) signaling pathway. Our previous work established the concept of MC-GAG as a materials-only regenerative strategy. However, three questions require further investigation. First, what are the properties of MC-GAG that induce osteogenesis and can they be refined? Second, are there any untoward side effects with the usage of MC- GAG? Third, as cerebral protection is paramount in clinically relevant defects and regeneration offers no protection until healing is complete, would MC-GAG demonstrate the same amount of regeneration as a composite with a clinically available resorbable material for cerebral protection? In Aim 1, we will determine the contributions of calcium and phosphate-induced signaling and mechanical stiffness in MC-GAG-mediated osteogenesis in human mesenchymal stem cells. We hypothesize that calcium and phosphate ion signaling may be the primary triggers for osteogenic differentiation on MC-GAG, bridging the connection between the material, autogenous BMPR signaling, matrix mineralization, and bone healing. In Aim 2, we will evaluate a composite of MC-GAG with poly-D,L-lactide (PDLLA) mesh, a clinically available resorbable cranioplasty material, in a rabbit calvarial defect model for biomechanical properties, vascularity, inflammation, bone healing, and local and systemic safety. We hypothesize that MC-GAG/PDLLA composites would result in bone regeneration equivalent to MC-GAG alone and add the dimension of cerebral protection during regeneration. Our proposed studies are unified in the goal of calvarial regenerative technology development. The current proposal will allow us to understand mechanistic interactions between MC-GAG and progenitor cells to further refine the material and to generate preclinical safety and performance data for an IDE application to the FDA.