Tissue Vascularization Using Blood- or Bone-Marrow-derived Progenitor Cells

描述（由申请人提供）： 我们的目标是从人内皮祖细胞（EPCs）和平滑肌祖细胞（SMPCs）构建血管网络，以重建受损的组织和器官。我们和其他人已经表明，人EPCs和SMPCs可以从血液或骨髓中获得，并在实验室中扩增没有困难。我们发表的和初步的数据表明，这些细胞在体内使用基质胶模型和免疫缺陷小鼠的血管生成能力。在未来，我们设想使用患者自己的EPCs和SMPCs的各种组织工程（TE）的应用和原位再生缺血组织中的血管网络。对于组织工程（TE），将由EPC/SMPC产生的血管网络在体外并入组织工程构建体中，使得在体内植入后，与宿主循环的血管化迅速发生以建立血流.对于原位组织再生，EPC/SMPC将被递送到体内部位，在那里它们将经历血管发生，正如我们已经证明的那样，可以在体内Matrigel模型中发生。我们的总体假设是，EPCs和SMPCs应用于组织工程（TE）器官或原位缺血组织将建立足够的血液供应，从而促进驻留细胞进行适当的组织发育和再生。在本提案中，我们将使用我们用人EPCs和SMPCs建立的体内模型确定关键参数，以加速血管生成过程至24-48小时的时间范围。接下来，我们将测试在生物可降解支架内体外预形成的血管网络在体内植入后与宿主循环形成血管网的能力。最后，我们将测试EPC/SMPCs是否会在缺血心肌中进行血管生成，如果是这样，评估对心脏恢复的影响。总之，我们设想我们的双细胞系统作为一种使能技术，可以应用于许多不同的组织/器官，其中需要功能性血管。我们还将基于细胞的再生方法视为一个连续体-从TE，其中接种到支架材料上的自体细胞通过生物化学和机械力刺激以形成组织，到原位组织再生，其中内源性细胞修复过程通过许多不同的机制增强。沿着这个连续体，血管化的时机和程度将是重建复杂组织的关键组成部分。 公共卫生相关性声明（由申请方提供）：我们的目标是确定由血液或骨髓来源的内皮和平滑肌祖细胞创建的血管网络是否会缓解缺血并促进组织修复。本质上，我们正在测试用两种高度纯化和确定的细胞类型启动血管化过程是否会增加和/或加速内源性修复和再生机制。我们认为，这种双细胞系统是一种使能技术，可以应用于许多不同的组织和器官，其中需要功能性血管。这项建议将集中在缺血心肌的修复，但我们设想，我们的组织血管化的策略将适用于组织工程和再生医学的许多方面。

DESCRIPTION (provided by applicant): Our goal is to build vascular networks from human endothelial progenitor cells (EPCs) and smooth muscle progenitor cells (SMPCs) to re-build damaged tissues and organs. We and others have shown that human EPCs and SMPCs can be obtained from blood or bone marrow and expanded in the laboratory without difficulty. Our published and preliminary data demonstrate the vasculogenic capability of these cells in vivo using a Matrigel model and immunodeficient mice. In the future, we envision use of a patient's own EPCs and SMPCs for a variety of tissue-engineering (TE) applications and for in situ regeneration of vascular networks in ischemic tissue. For tissue- engineering (TE), vascular networks created from EPCs/SMPCs would be incorporated into tissue- engineered constructs in vitro such that upon implantation in vivo, anastomoses with the host circulation occur rapidly to establish blood flow. For tissue regeneration in situ, EPCs/SMPCs would be delivered to the site in vivo where they will undergo vasculogenesis, as we have demonstrated can occur in an in vivo Matrigel model. Our overall hypothesis is that EPCs and SMPCs applied to either a tissue-engineered (TE) organ or in situ to ischemic tissue will establish an adequate blood supply and thereby promote resident cells to undergo appropriate tissue development and regeneration. In this proposal, we will determine key parameters to accelerate the vasculogenic process to a time frame of 24-48 hours using the in vivo model we have established with human EPCs and SMPCs. Next, we will test the ability of vascular networks preformed in vitro within biodegradable scaffolds to form anastomoses with the host circulation upon implantation in vivo. Finally, we will test whether EPC/SMPCs will undergo vasculogenesis in ischemic myocardium and if so, evaluate the effect on recovery of the heart. In summary, we envision our two-cell system as an enabling technology that can be applied to many different tissues/organs wherein functional blood vessels are needed. We also view cell-based regenerative approaches as a continuum - from TE in which autologous cells seeded onto scaffold materials are stimuated by biochemical and mechanical forces to form tissue, to in situ tissue regeneration in which endogenous cellular repair processes are enhanced by a number of different mechanisms. Along this continuum, the timing and degree of vascularization will be a critical component for rebuilding complex tissues. Public Health Relevance Statement (provided by applicant): Our goal is to determine if vascular networks created from blood- or bone marrow-derived endothelial and smooth muscle progenitor cells will alleviate ischemia and promote tissue repair. In essence we are testing whether jump-starting the vascularization process with two highly purified and defined cell types will augment and/or accelerate the endogenous repair and regenerative mechanisms. We propose that this two-cell system is an enabling technology that can be applied to many different tissues and organs wherein functional blood vessels are needed. This proposal will focus on repair of ischemic myocardium, but we envision that our strategy for tissue vascularization will be applicable to tissue-engineering and to many aspects of regenerative medicine.