Microengineered Osteoinductive and Vasculogenic Scaffold

微工程骨诱导和血管生成支架

基本信息

批准号：
8722953
负责人：
Esmaiel Jabbari
金额：
$ 32.83万
依托单位：
UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-09-01 至 2015-08-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The major challenge in reconstruction of large bone defects is that the maturation of osteogenic and vasculogenic cells require complementary microenvironments. The aim of this project is to develop a 3D multilayer cell-laden composite construct with spatially organized microchannels to mimic the "osteoblastic- vascular" niche in the bone marrow, and to address the issues of tissue architecture and cell microenvironment. In bone tissue, the soft permissive vasculoinductive microenvironment of the marrow stroma supports vasculogenesis while the osteoinductive endosteal layer bound to the osseous tissue supports mineralization and bone formation. The hypotheses are: a) an osteoinductive high modulus hydrogel with and long-degradation time (SPELA gel) provides a microenvironment for mineralization of marrow stromal cells (MSCs); b) a high compliance hydrogel with short degradation (GelMA gel) provides a permissive microenvironment for vascularization of endothelial progenitor cells (EPCs); c) microchannels of the soft GelMA gel patterned in the SPELA gel provide a permissive and instructive "osteoblastic-vascular" niche for concurrent vascularization and mineralization in the composite matrix; and d) the micropatterning process can be repeated to produce a 3D multilayer construct. We propose the following aims to engineer and evaluate the cellular constructs for regeneration of bone segments. In Aim 1.1, we will synthesize the SPELA hydrogel with short lactide segments as a degradable matrix with robust compressive modulus to support encapsulation and mineralization of MSCs. In Aim 1.2, we will supplement the SPELA hydrogel with osteoinductive rhBMP-2 protein grafted to self-assembled nanoparticles to prevent migration of the protein and confine its osteoinductivity to the SPELA matrix. In Aim 1.3, we will synthesize a gelatin-based GelMA hydrogel as a permissive matrix to support vasculogenic differentiation and maturation of bone marrow derived EPCs and MSCs and vessel formation. In Aim 2.1, we will fabricate microchannels of EPC/MSC- seeded GelMA gel in MSC-seeded SPELA hydrogel to form a "gel-in-gel" tissue layer with spatially organized microvessels in the mineralizing SPELA hydrogel. In Aim 2.2, we will engineer macroporous tissue layers, integrate the layers into 3D multilayer constructs with spatially organized microchannels, and determine viability of the embedded cells in the central part of the construct. In Aim 2.3, we will evaluate the 3D multilayer cell-laden constructs with respect to mineralization and vascularization in vitro. In Aim 3, the patterned cell-laden 3D constructs will be evaluated in vivo in rat segmental femur defect for the extent of bone formation and healing. This is a clinically viable approach as MSCs and EPCs can be isolated from the bone marrow of the patient and embedded in the construct prior to implantation in a large bone defect.

描述（由申请人提供）：大骨缺损重建的主要挑战是成骨细胞和血管生成细胞的成熟需要互补的微环境。该项目的目的是开发一种具有空间组织微通道的 3D 多层充满细胞的复合结构，以模拟骨髓中的“成骨细胞-血管”生态位，并解决组织结构和细胞微环境的问题。在骨组织中，骨髓基质的柔软的允许血管诱导微环境支持血管生成，而与骨组织结合的骨诱导内膜层支持矿化和骨形成。假设是：a）具有长降解时间的骨诱导高模量水凝胶（SPELA 凝胶）为骨髓基质细胞（MSC）矿化提供微环境； b) 具有短降解能力的高顺应性水凝胶（GelMA 凝胶）为内皮祖细胞（EPC）的血管化提供了良好的微环境； c) SPELA 凝胶中图案化的软 GelMA 凝胶的微通道为复合基质中同时的血管化和矿化提供了允许和指导性的“成骨细胞-血管”生态位； d) 可以重复微图案化过程以产生 3D 多层构造。我们提出以下目标来设计和评估用于骨段再生的细胞结构。在目标 1.1 中，我们将合成具有短丙交酯片段的 SPELA 水凝胶作为具有强大压缩模量的可降解基质，以支持 MSC 的封装和矿化。在目标 1.2 中，我们将用移植到自组装纳米颗粒上的骨诱导性 rhBMP-2 蛋白补充 SPELA 水凝胶，以防止蛋白质迁移并将其骨诱导性限制在 SPELA 基质中。在目标 1.3 中，我们将合成一种基于明胶的 GelMA 水凝胶作为允许基质，以支持骨髓来源的 EPC 和 MSC 的血管生成分化和成熟以及血管形成。在目标 2.1 中，我们将在接种 MSC 的 SPELA 水凝胶中制造接种 EPC/MSC 的 GelMA 凝胶的微通道，以在矿化 SPELA 水凝胶中形成具有空间组织微血管的“凝胶中凝胶”组织层。在目标 2.2 中，我们将设计大孔组织层，将这些层集成到具有空间组织微通道的 3D 多层结构中，并确定结构中心部分嵌入细胞的活力。在目标 2.3 中，我们将评估 3D 多层充满细胞的构建体的体外矿化和血管化。在目标 3 中，将在大鼠股骨节段缺损体内评估图案化的充满细胞的 3D 构建体的骨形成和愈合程度。这是一种临床上可行的方法，因为 MSC 和 EPC 可以从患者的骨髓中分离出来，并在植入大骨缺损之前嵌入到构建体中。