Osteoclast modulatory biomaterials for skull regeneration

项目摘要/摘要 颅骨缺陷继发于创伤、中风、癌症和先天性畸形，导致显著的 神经、心理、社会和职业负担。目前颅骨成形术或颅骨成形术的临床选择 重建，受到自体骨移植的可用性和发病率以及并发症和成本的限制 同种异形材料。这些缺点提供了一个机会来开发专门针对 颅骨再生。尽管经过了几十年的研究，当代的再生战略包括 由支架材料输送的扩增干细胞和生长因子鸡尾酒尚未达到临床 由于手术不切实际、成本、时间消耗和安全考虑而导致的翻译。不断增长的 细胞外基质(ECM)在细胞命运决定中的指导能力的知识提供了一种 再生的另一种范例。我们演示了一种受ECM启发的材料，由 纳米粒矿化胶原糖胺聚糖(MC-GAG)可再生高达60%的矿化 无体外祖细胞负载或外源性生长的天然颅骨的生物力学特性 因子补充剂。同时，MC-GAG抑制破骨细胞的激活和吸收，而不影响 破骨细胞通过直接材料与细胞相互作用提供的旁分泌成骨特性 间接通过诱导骨祖细胞分泌骨保护素(OPG)，OPG是一种内源性抑制因子 破骨细胞激活。随着外源性OPG的加入，这种成骨作用从 破骨细胞的生成得到加强。总而言之，这些数据提供了一个原则证据，即 MC-GAG和OPG(MCGO)材料以时间受限的方式交付可能是一种潜在的 颅骨再生的材料。为了开发临床翻译的MCGO材料，有三个 必须回答的问题：1.破骨细胞通过与 由于破骨细胞的吸收能力是骨重建和成熟所必需的， OPG应该在系统中存在多长时间？3.OPG应该被洗脱还是固定在物质上？回答 针对这些问题，我们开发了两种通过非共价和共价掺入OPG的MCGO材料 从而得到高浓度、快速释放和低浓度、缓释的MCGO材料， 分别进行了分析。在目标1中，我们将阐明MC-GAG和MGAG诱导的抗破骨细胞形成的机制。 MCGO材料。我们假设MC-GAG和两种MCGO材料将对HOC产生不同的影响 活化和再吸收。在目的2中，我们将评估两种MCGO材料与MC-GAG在兔体内的比较 颅骨再生为MCGO材料产生临床前疗效、安全性和性能数据 与MC-GAG相比。我们建议的研究统一在颅骨再生技术的目标上 发展。在拟议的研究结束时，我们预计已经积累了大量的临床前研究 支持向FDA提交MCGO材料的IDE应用程序的数据。

PROJECT SUMMARY/ABSTRACT Skull defects occur secondary to trauma, stroke, cancer, and congenital anomalies resulting in significant neurological, psychological, social, and vocational burdens. Current clinical options for cranioplasty, or calvarial reconstruction, are limited by availability and morbidity in autologous bone grafts and complications and cost in alloplastic materials. Such drawbacks provide an opportunity 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 due to surgical impracticality, cost, time consumption, and safety concerns. The increasing knowledge of instructive capabilities of the extracellular matrix (ECM) in cell fate determination has provided an alternative paradigm for regeneration. We demonstrated that an ECM-inspired material composed of nanoparticulate mineralized collagen glycosaminoglycan (MC-GAG) regenerates up to 60% the mineralization and biomechanical properties of native calvarium without ex vivo progenitor cell loading or exogenous growth factor supplementation. Simultaneously, MC-GAG inhibits osteoclast activation and resorption without affecting the paracrine osteoinductive properties offered by osteoclasts via direct material to cell interactions as well as indirectly by inducing osteoprogenitors to secrete osteoprotegerin (OPG), an endogenous inhibitor for osteoclast activation. With the addition of exogenous OPG, this uncoupling of osteogenesis from osteoclastogenesis is augmented. In combination, these data provided a proof of principle that a composite material of MC-GAG and OPG (MCGO) delivered in a temporospatially-limited manner may be a potential material for calvarial regeneration. In order to develop the MCGO material for clinical translation, three questions must be answered: 1. What are the mechanisms activated in osteoclasts by direct interactions with MC-GAG? 2. As the resorptive abilities of osteoclasts are necessary for remodeling and maturation of bone, how long should OPG exist in the system? 3. Should OPG be eluted or anchored to the material? To answer these questions, we have developed two MCGO materials via non-covalent and covalent incorporation of OPG resulting in a high concentration, fast release and a low concentration, extended release MCGO material, respectively. In Aim 1, we will elucidate the anti-osteoclastogenic mechanisms induced by MC-GAG and MCGO materials. We hypothesize that MC-GAG and the two MCGO materials will differentially affect hOC activation and resorption. In Aim 2, we will evaluate the two MCGO materials compared to MC-GAG in rabbit calvarial regeneration to generate preclinical efficacy, safety, and performance data for MCGO materials compared to MC-GAG. Our proposed studies are unified in the goal of calvarial regenerative technology development. At the conclusion of the proposed studies, we expect to have amassed significant preclinical data to support an IDE application for MCGO materials to the FDA.