Aligned Nanofibrillar Scaffolds Enhance Angiogenesis and Viability in Ischemia

对齐的纳米纤维支架增强缺血中的血管生成和活力

• 批准号: 9208640
• 负责人: Ngan F. Huang
• 金额: $ 47.18万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2021-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9208640
• 关键词: Address; Alpha Cell; Anatomy; Angiography; Animal Model; Animals; Apoptosis; Arterial Occlusive Diseases; Arteries; Biocompatible Materials; Biomimetics; Blood; Blood Vessels; Blood flow; Cell Survival; Cells; Clinical Trials; Collagen; Collagen Fibril; Cues; Cultured Cells; Data; Development; Disease model; Electrospinning; Endothelial Cells; Endothelium; Experimental Models; Fibrillar Collagen; Fluorescence; Gangrene; Goals; Growth Factor; Hindlimb; Histologic; Human; Hydrogels; Hypoxia; Image; Implant; In Vitro; Injectable; Ischemia; Kinetics; Lasers; Leg; Limb structure; Mechanics; Metabolic; Methods; Mind; Modeling; Natural regeneration; Nitric Oxide; Pain; Patients; Peripheral arterial disease; Positron-Emission Tomography; Process; Production; Property; Recovery; Reporter; Role; Secondary to; Signal Transduction; Spectrum Analysis; Stem cells; Structure; Testing; Tissues; Vascular blood supply; Vascularization; X-Ray Computed Tomography; angiogenesis; arm; base; bioluminescence imaging; blood perfusion; clinical efficacy; clinical translation; clinically translatable; cytokine; endothelial dysfunction; implantation; improved; in vivo; induced pluripotent stem cell; limb amputation; migration; minimally invasive; mouse model; nanopattern; nanoscale; novel strategies; paracrine; public health relevance; response; scaffold; stem cell therapy; treatment group; vascular endothelial dysfunction

 DESCRIPTION (provided by applicant): Over 8 million people in the US suffer from peripheral arterial disease (PAD), which is characterized by narrowing of the arteries that supply blood flow to the limbs, leading to tissue ischemia. A central feature of PAD is dysfunction of the vascular endothelial cells (ECs) that control vascular reactivity and angiogenesis. We previously demonstrated that ECs derived from human induced pluripotent stem cells (iPSC-ECs) can improve blood perfusion in animals with induced hindlimb ischemia, an experimental model of PAD. However, poor cell survival limited their angiogenic potential. To address this limitation, we seek to develop aligned nanofibrillar collagen scaffolds that mimic the crimped (wavy) structure of native collagen fibrils. In comparison to injectable scaffolds, which lack organized nano-scale structure and mechanical integrity, our preliminary data suggests that aligned nanofibrillar scaffolds provide structural support for guiding the organization of newly formed vessels, directing cell survival, and stimulating angiogenesis. The global hypothesis is that crimped aligned nanofibrillar scaffolds seeded with iPSC-ECs will enhance cell survival, accelerate vascular network formation, and induce angiogenesis in the ischemic limb in small and large animal PAD models. In this resubmission application, Specific Aim 1 will test the hypothesis that crimped aligned nanofibrillar scaffolds, in contrast to randomly oriented scaffolds, will enhance iPSC-EC survival and angiogenesis in vitro. For up to 14 days, cell viability and angiogenesis (migration, vascular network formation, and cytokine production) will be quantitatively compared between iPSC-ECs that are seeded on aligned or randomly oriented scaffolds under hypoxia (1% O2). To validate these findings in vivo, Specific Aim 2 will compare the temporal process of angiogenesis, arteriogenesis, and cell survival after implantation of the iPSC-EC-seeded aligned nanofibrillar scaffold into the ischemic limb. Over 28 days, cell survival, blood perfusion recovery, and formation of new microvasculature will be quantitatively assessed by bioluminescence imaging, laser Doppler blood spectroscopy, and micro computed tomography imaging, respectively, between cells seeded on aligned or randomly oriented scaffolds. Towards clinical translation, Specific Aim 3 will be an exploratory study in which iPSC-ECs seeded on aligned or randomly oriented scaffolds will be implanted into an ovine limb ischemia model. Cell survival will be tracked by. The temporal process of microvessel formation and blood perfusion recovery will be assessed by computed tomography and fluorescence assisted angiography, respectively. Anatomical tunneling of the scaffolds to the ischemic limb will also be examined as a clinically translatable minimally invasive delivery approach. Together, the results of these studies will lead to the development of biomimetic nanofibrillar scaffolds to improve the clinical efficacy of stem cell therapy to PAD patients. We have generated the preliminary scientific components and assembled the expertise to hopefully successfully achieve these goals.

 描述（由申请人提供）：在美国，超过800万人患有外周动脉疾病（PAD），其特征在于向肢体供应血流的动脉变窄，导致组织缺血。PAD的中心特征是控制血管反应性和血管生成的血管内皮细胞（EC）的功能障碍。我们以前证明，来自人诱导多能干细胞（iPSC-ECs）的ECs可以改善诱导后肢缺血动物（PAD的实验模型）的血液灌注。然而，较差的细胞存活限制了它们的血管生成潜力。为了解决这一限制，我们寻求开发模拟天然胶原原纤维的卷曲（波浪形）结构的对齐的纳米原纤维胶原支架。与缺乏有组织的纳米尺度结构和机械完整性的可注射支架相比，我们的初步数据表明，对齐的纳米纤维支架为引导新形成的血管的组织、指导细胞存活和刺激血管生成提供了结构支持。总体假设是，在小型和大型动物PAD模型中，接种有iPSC-EC的卷曲对齐的纳米纤维支架将增强细胞存活，加速血管网络形成，并诱导缺血肢体中的血管生成。 在这次重新提交申请中，具体目标1将测试卷曲排列的纳米纤维支架与随机取向的支架相比将增强iPSC-EC存活和体外血管生成的假设。在长达14天的时间内，将在缺氧（1% O2）下接种在对齐或随机定向支架上的iPSC-EC之间定量比较细胞活力和血管生成（迁移、血管网络形成和细胞因子产生）。为了在体内验证这些发现，Specific Aim 2将比较在将iPSC-EC接种的对齐纳米原纤支架植入缺血肢体后血管生成、动脉生成和细胞存活的时间过程。在28天内，将分别通过生物发光成像、激光多普勒血液光谱和微型计算机断层扫描成像来定量评估接种在对齐或随机定向支架上的细胞之间的细胞存活、血液灌注恢复和新微血管的形成。对于临床转化，Specific Aim 3将是一项探索性研究，其中将在对齐或随机定向的支架上接种的iPSC-EC植入绵羊肢体缺血模型中。细胞存活率将通过。将分别通过计算机断层扫描和荧光辅助血管造影术评估微血管形成和血液灌注恢复的时间过程。支架到缺血肢体的解剖隧道也将作为临床上可转化的微创递送方法进行检查。总之，这些研究的结果将导致仿生纳米纤维支架的开发，以提高干细胞治疗PAD患者的临床疗效。我们已经产生了初步的科学组成部分，并汇集了专业知识，希望能成功实现这些目标。