Scalable Units for Building Vascularized Cardiac Graft

描述(申请人提供)：最近在心肌组织工程学方面的研究表明，结合弹性和强度的机械坚固的微制生物材料，以及基于细胞的策略，可以提高移植心脏和/或干细胞的存活率和血管整合。然而，创造能够有组织收缩功能的心肌移植物，以及在植入后快速血管化厚壁心肌移植物的方法仍然是尚未解决的问题，这些问题目前限制了新的心肌再生技术的尺寸和临床应用。构建由心脏细胞、内皮细胞和可缓慢生物降解的弹性支架组成的血管化心脏移植物的可扩展单元将是因缺血或先天性心脏病而失去功能的心肌再生的范式转变。这项拟议工作的目标是：(I)设计弹性支架，为培养和排列心脏细胞提供实质性空间，(Ii)将这些构建块与可灌流的通道网络相结合，为培养内皮细胞提供血管内空间，以及(Iii)显示所产生的心肌移植物可以提供机械支持，并在啮齿动物模型中提供可行的心肌梗死后移植的心脏细胞。在目标1中，我们将用聚庚二酸甘油和弹性蛋白创建弹性支架，并测试支架结构特征(即长方形毛孔与排列的弹性蛋白微纤维相结合)将指导培养的心脏细胞伸长、排列和收缩的假设。在目标2中，我们将结合构建块(即，具有培养的心脏细胞的弹性支架)和可灌流的通道网络，以形成由血管内和实质空间组成的可扩展单元。我们将验证这样的假设，即血管内间隙的灌流将增强实质间隙中心脏细胞的存活，我们将在体外将通道与内皮细胞连接。在目标3中，我们将使用四个实验组来评估手术诱导的心肌梗死后的啮齿类动物的心肌移植：(I)含有血管内皮细胞和实质心脏细胞的弹性支架；(Ii)仅含有心脏细胞的弹性支架；(Iii)不含任何细胞的弹性支架；以及(Iv)未处理的心肌梗死。我们将验证弹性支架将保留心肌梗死后的心功能，外源性心肌细胞将存活并与宿主心肌机电结合，内皮化的通道将与宿主血管形成功能性吻合的假设。这项工作的主要创新是设计和演示：(I)用于组织工程和再生医学的弹性构建块支架，(Ii)由血管内和实质隔室组成的层状可伸缩单元，用于再生高度血管化的组织(例如，心脏、骨骼和平滑肌、肝脏、肾脏)，以及(Iii)用于再生其他各向异性承载组织(例如，血管、韧带、肌腱、软骨和骨骼)的各向异性支架。

DESCRIPTION (provided by applicant): Recent research in myocardial tissue engineering has demonstrated the promise of mechanically robust microfabricated biomaterials that combine elasticity and strength, and cell-based strategies that enhance the survival and vascular integration of transplanted heart and/or stem cells. However, creation of myocardial grafts capable of organized contractile function, and a means to rapidly vascularize thick myocardial grafts upon implantation remain unsolved problems that currently limit the dimensions and clinical translation of new myocardial regenerative technologies. Scalable units for building vascularized cardiac grafts comprised of heart cells, endothelial cells, and slowly biodegradable elastomeric scaffolds would be a paradigm shift in the regeneration of myocardium rendered non-functional by ischemia or congenital heart disease. The goals of the proposed work are to: (i) design elastomeric scaffolds that provide parenchymal spaces for culturing and aligning heart cells, (ii) combine these building blocks with perfusable channel networks that provide intravascular spaces for culturing endothelial cells, and (iii) show that the resulting myocardial grafts can provide mechanical support and viable, transplanted heart cells after myocardial infarction (MI) in a rodent model. In Aim 1, we will create elastomeric scaffolds from poly (glycerol-sebacate) and elastin, and test the hypothesis that scaffold structural features (i.e., rectangular pores combined with aligned elastin microfibers) will guide the elongation, alignment, and contractility of cultured heart cells. In Aim 2, we will combine building blocks (i.e., elastomeric scaffolds with cultured heart cells) and perfusable channel networks to form scalable units comprised of intravascular and parenchymal spaces. We will test the hypotheses that perfusion of the intravascular spaces will enhance heart cell survival in the parenchymal spaces, and we will line the channels with endothelial cells in vitro. In Aim 3, we will evaluate the myocardial grafts in rodents after surgically induced MI by using four experimental groups: (i) elastomeric scaffolds with intravascular endothelial cells and parenchymal heart cells; (ii) elastomeric scaffolds with only heart cells, (iii) elastomeric scaffolds without any cells, and (iv) untreated MI. We will test the hypotheses that elastomeric scaffolds will preserve ventricular function post-MI, exogenous heart cells will survive and integrate electromechanically with host myocardium, and endothelialized channels will form functional anastomoses with host vessels. The main novelties of this work are the design and demonstration of: (i) elastomeric building-block scaffolds for tissue engineering and regenerative medicine, (ii) lamellar scalable units comprised of intravascular and parenchymal compartments for regenerating highly vascularized tissues (e.g., cardiac, skeletal and smooth muscle, liver, kidney), and (iii) anisotropic scaffolds for regenerating other anisotropic, load-bearing tissues (e.g., blood vessel, ligament, tendon, cartilage, and bone).