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）：重建大骨缺陷的主要挑战是成骨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具有空间有组织的微通道的3D多层细胞复合构建体，以模仿骨髓中的“成骨细胞血管”小裂，并解决组织结构和细胞微环境的问题。在骨组织中，骨髓基质的柔软允许性血管诱导微环境支持血管生成，而与骨组织结合的骨诱导的内骨层则支持矿化和骨形成。假设是：a）骨诱导的高模量水凝胶，并具有长度降解时间（SPELA凝胶）提供了一种微环境，可用于矿物质的骨髓基质细胞（MSC）； b）具有短降解（GELMA凝胶）的高依从性水凝胶为内皮祖细胞的血管形成（EPC）提供了宽松的微环境； c）在SPELA凝胶中图案的软凝胶凝胶的微通道提供了一种允许和启发性的“成骨细胞 - 血管 - 血管生态”，用于复合基质中的同时血管化和矿化； d）可以重复微观图案过程以产生3D多层构建体。我们提出以下旨在设计和评估骨骼段再生的细胞构建体。在AIM 1.1中，我们将用短乳酸片段将SPELA水凝胶合成为具有稳健压缩模量的可降解基质，以支持MSC的封装和矿化。在AIM 1.2中，我们将用移植到自组装的纳米颗粒中的骨诱导RHBMP-2蛋白来补充Spela水凝胶，以防止蛋白质迁移并将其骨诱导限制在Spela基质中。在AIM 1.3中，我们将合成一个基于明胶的胶凝水凝胶作为宽敞的基质，以支持血管生成分化和骨髓衍生的EPCS，MSC和血管形成的成熟。在AIM 2.1中，我们将在MSC种子的SPELA水凝胶中制造EPC/MSC种子凝胶的微通道，以形成一个“凝胶中的凝胶”组织层，并在矿化的spela水凝胶中使用空间有组织的微量固定。在AIM 2.2中，我们将设计大孔组织层，将层与空间有组织的微通道整合到3D多层构建体中，并确定构造中心部分中嵌入式细胞的可行性。在AIM 2.3中，我们将根据体外矿化和血管化评估3D多层细胞构建体。在AIM 3中，将在大鼠节股股骨缺陷中评估带有图案的含有细胞的3D构建体，以实现骨形成和愈合的程度。这是一种临床上可行的方法，因为可以从患者的骨髓中分离出MSC和EPC，并在植入大骨缺陷之前嵌入构造中。