Scalable Units for Building Vascularized Cardiac Graft

描述（由申请人提供）：心肌组织工程的最新研究已经证明，结合了联合收割机弹性和强度的机械坚固的微制造生物材料，以及增强移植心脏和/或干细胞的存活和血管整合的基于细胞的策略的前景。然而，能够有组织的收缩功能的心肌移植物的产生，以及在植入时使厚的心肌移植物快速血管化的手段仍然是未解决的问题，这些问题目前限制了新的心肌再生技术的尺寸和临床转化。用于构建由心脏细胞、内皮细胞和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缺血或先天性心脏病导致无功能的心肌再生的范式转变。所提出的工作的目标是：（i）设计弹性支架，提供实质空间的培养和对齐的心脏细胞，（ii）联合收割机这些构件与灌注通道网络，提供血管内空间培养内皮细胞，和（iii）表明，所得的心肌移植物可以提供机械支持和可行的，移植的心脏细胞心肌梗死（MI）后，在啮齿动物模型。在目标1中，我们将从聚（甘油-癸二酸酯）和弹性蛋白产生弹性支架，并测试支架结构特征（即，与排列的弹性蛋白微纤维结合的矩形孔）将引导培养的心脏细胞的伸长、排列和收缩。在目标2中，我们将联合收割机构建模块（即，具有培养的心脏细胞的弹性支架）和可灌注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。我们将检验血管内空间的灌注将增强实质空间中的心脏细胞存活的假设，并且我们将在体外用内皮细胞内衬通道。在目标3中，我们将通过使用四个实验组来评估手术诱导的MI后啮齿动物中的心肌移植物：（i）具有血管内内皮细胞和实质心脏细胞的弹性体支架;（ii）仅具有心脏细胞的弹性体支架;（iii）不具有任何细胞的弹性体支架;和（iv）未处理的MI。我们将测试的假设，弹性支架将保持心肌梗死后的心室功能，外源性心脏细胞将生存和整合机电与宿主心肌，内皮化的通道将形成功能性血管内皮。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体构建块支架，（ii）由血管内和实质隔室组成的层状可扩展单元，用于再生高度血管化的组织（例如，心脏、骨骼和平滑肌、肝、肾），和（iii）用于再生其它各向异性的、承重组织的各向异性支架（例如，血管、韧带、腱、软骨和骨）。

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).