Mechanisms of ECM Scaffold Remodeling

描述（由申请人提供）： 这项修订提案的长期目标是发展组织工程策略，促进用于组织和器官重建的支架的建设性重塑和血管化。目前的四年计划将利用异种细胞外基质（ECM）来自猪膀胱（UB-ECM）作为测试支架材料和两个动物模型的食管重建作为临床前体内测试系统。将研究关于支架重塑机制的三个重要问题：1）有助于重塑过程的细胞来源，2）支架降解与血管化和组织重建的时间和空间关联，以及3）体外在支架内接种和培养细胞以促进随后的体内血管化和重塑的概念。有四个具体目标，每一个都通过一个受控的、精心设计的研究来解决。第一个具体目标将检查宿主骨髓源性细胞作为支架重塑的多潜能细胞来源的概念。该目标还将检查蛋白质交联对填充这些支架的细胞来源的影响。第二个特定目标将确定ECM支架降解的速率、降解产物的命运以及支架降解与重塑过程的关联。第三和第四个特定目的将分别研究在体内植入前在ECM支架内培养血管壁前体细胞或骨髓来源的内皮前体细胞对支架重塑的影响。所有研究都是基于广泛的初步数据和明确陈述的假设。这些研究旨在了解支架重塑的机制，并将学到的原理应用于更广泛的组织工程应用。这项工作将由一个经验丰富的跨学科科学家小组进行，并提出了完成这项工作的时间轴。

DESCRIPTION (provided by applicant): The long-term objective of this revised proposal is the development of tissue engineering strategies that will promote the constructive remodeling and vascularization of scaffolds used for tissue and organ reconstruction. The present four-year proposal would utilize xenogeneic extracellular matrix (ECM) derived from porcine urinary bladder (UB-ECM) as the test scaffold material and two animal models of esophageal reconstruction as the preclinical in vivo test system. Three important issues concerning the mechanisms of scaffold remodeling will be studied: 1) the source of cells that contribute to the remodeling process, 2) the temporal and spatial association of scaffold degradation with vascularization and tissue reconstruction, and 3) the concept of seeding and culturing cells within scaffolds in vitro to promote subsequent in vivo vascularization and remodeling. There are four Specific Aims, each of which is addressed by a controlled, carefully designed study. The first Specific Aim will examine the concept of host bone marrow-derived cells as a source of multi-potential cells for scaffold remodeling. This Aim will also examine the effect of protein cross-linking upon the source of cells that populate these scaffolds. The second Specific Aim will determine the rate of ECM scaffold degradation, the fate of degradation products, and the association of scaffold degradation with the remodeling process. The third and fourth Specific Aims will investigate the effect upon scaffold remodeling of culturing vascular mural precursor cells or marrow-derived endothelial precursor cells, respectively, within the ECM scaffold prior to in vivo implantation. All studies are based upon extensive preliminary data and upon clearly stated hypotheses. The studies are directed toward understanding the mechanisms of scaffold remodeling and applying the learned principles to broader tissue engineering applications. The work will be conducted by an experienced interdisciplinary team of scientists and a timeline is presented for completion of the work.