Bio-printing stem cell based and oxygen releasing tissue grafts for myocardial in

描述（由申请人提供）：估计有8000万美国成年人（三分之一）患有一种或多种心血管疾病（CVD）；790万人有心肌梗塞史（美国心脏协会）。干细胞治疗是一种很有前途的心肌梗死修复方法，使用干细胞修复受损心脏是目前心脏研究的主流。不幸的是，到目前为止，将干细胞直接注射到梗死心脏的纤维化区域取得的成功有限，这可能是由于干细胞在坏死区域的保留率和存活率较低，以及宿主心脏组织内递送细胞的心源性分化和功能整合有限。为了解决这些问题，最近提出了一种组织工程支架方法，包括使用人工合成的组织支架，将干细胞植入生物工程移植物框架中。然而，由于合成支架与干细胞结合的经验不足，以及如何改善支架的几何形状和组成以促进血管重建和改善移植物微环境以提高干细胞的活力、生长和分化，因此取得的成功有限。我们的建议通过结合使用可生物降解弹性体和氧气释放支架用于间充质干细胞治疗的新策略来解决这些局限性。为此，我们将使用聚合物静电纺丝和微喷射细胞打印的混合生物打印技术来制造一个耐用的基于干细胞的多层3d心脏贴片。在这种生物工程结构中，支架作为一种有效的干细胞载体和3-D弹性物理结构，用于肌细胞生长和机电耦合。在我们的支架中包含过氧化钙氧释放纳米颗粒，改善了微环境，增强了干细胞的存活和它们与受损心脏组织的整合。因此，我们提出4个具体目标：制备和表征心脏贴片支架材料。2. 优化氧释放颗粒入支架的最大氧气输送和最小的毒性。3. 采用混合制备生物技术制备复合心脏贴片。4. 对生物工程心脏贴片进行体外评价。总之，拟议的项目将通过为细胞提供稳定的递送载体和可调节的局部环境来增强和调节细胞增殖和分化，从而改善当前心肌梗死的干细胞治疗。此外，通过生物打印关键信号肽和其他用于修复软组织损伤的支架的分子，这一努力保证了未来方法的改进。

DESCRIPTION (provided by applicant): An estimated 80,000,000 American adults (one in three) have one or more types of cardiovascular disease (CVD); 7,900,000 have a history of myocardial infarction (American Heart Association). Stem cell therapy is a promising approach for myocardial infarction repair, and the use of stem cells to repair a damaged heart is now mainstream in current cardiac research. Unfortunately, thus far direct injection of stem cells into the fibrotic area of infarcted hearts has met with limited success, probably due to the low retention and survival of stem cells in the necrotic areas, together with the limited cardiogenic differentiation and functional integration of delivered cells within the host heart tissue. To solve these problems, a tissue engineered scaffolding method has recently been proposed, involving the use of synthetic tissue scaffoldings with stem cells seeded and subsequently embedded within the bioengineered graft framework. However, limited success has been achieved due to inadequate experience in combining synthetic scaffolds with stem cells and limited knowledge of how to improve the geometry and composition of scaffolding to favor revascularization and improve the graft microenvironment for enhanced viability, growth, and differentiation of stem cells. Our proposal addresses these limitations with a new strategy that combines use of biodegradable elastomeric and oxygen-releasing scaffoldings for mesenchymal stem cell therapy. To this aim, we will use our hybrid bio-printing technology of polymer electrospinning and microjet cell printing to fabricate a durable stem cell based multilayered 3-D cardiac patch. In this bioengineered construct, the scaffold serves as an efficient stem cell carrier and 3-D elastomeric physical structure for myocyte growth and electro-mechanical coupling. The inclusion of calcium peroxide oxygen-releasing nanoparticles in our scaffoldings improves the microenvironment for enhanced survival of stem cells and their integration with the injured cardiac tissue. Therefore, we propose 4 Specific Aims: 1. Prepare and characterize scaffold materials for a cardiac patch. 2. Optimize incorporation of oxygen releasing particles into scaffolds for maximum oxygen delivery and minimal toxicity. 3. Fabricate a composite cardiac patch by using the hybrid fabrication biotechnology. 4. Conduct in vitro evaluation of the bio- engineered cardiac patch. Taken together, the proposed project will improve current stem cell therapy for myocardial infarct by providing cells with a stable delivery vehicle and an amenable local environment that enhances and regulates their proliferation and differentiation for cell-based tissue regeneration and repair. In addition, this effort promises future methodological improvements by bio-printing critical signaling peptides and other molecules for use in scaffolds designed to repair soft tissue injuries. PUBLIC HEALTH RELEVANCE: An estimated 80,000,000 American adults (one in three) have one or more types of cardiovascular disease (CVD); 7,900,000 have a history of myocardial infarction (American Heart Association). Stem cell therapy is a promising approach for myocardial infarction repair, and the use of stem cells to repair a damaged heart is now mainstream in current cardiac research. The proposed project will improve current stem cell therapy for myocardial infarct by providing cells with a stable delivery vehicle and an amenable local environment that enhances and regulates their proliferation and differentiation for cell-based tissue regeneration and repair.