Readily Available Stem Cell-Based Vascular Grafts for Emergent Surgical Care

因穿透(例如冲击伤)或钝性(例如骨折)而遭受血管损伤的患者 和交通事故造成的挫伤)创伤通常会对其小直径外周造成严重损害 动脉(2-4 mm，例如胫动脉或臂动脉)，需要手术干预以搭桥或替换伤者 血管节段。由于血管损伤患者的隐静脉可及性可能较低 因爆炸伤或严重交通意外而严重受伤或失去一条以上的肢体；以及 人工血管移植物的应用可能会受到传染性感染的潜在风险的阻碍。 由于这些类型损伤的性质，迫切需要一种替代的血管移植来源。脱细胞组织工程 因此，血管移植物(TEVGs)可以为急诊患者提供一种现成的治疗方法 血管创伤。虽然从原代培养中可以培养出机械强度很大的TEVG 人血管平滑肌细胞(VSMCs)脱细胞后，这个平台有几个障碍 这阻止了它最终为血管创伤的受害者提供服务。有限的可扩展性，有限的可访问性， 原代VSMC之间供体之间的功能差异可能会阻碍TEVG的生产效率。 此外，由于小直径TEVGs在植入前需要自体内皮细胞(EC)涂层以避免 血液衣物，病人内皮细胞因高龄或疾病而可能出现的功能障碍，以及 衍生和扩大患者的自体内皮细胞需要大量的时间，这可能会阻碍治疗的适用性 急性血管损伤。人诱导多能干细胞(HiPSCs)是一种体细胞来源的自我更新细胞 通过干细胞因子的异位表达，为解决并发症提供了极好的替代方案 基于原始细胞的TEVG。因为HiPSCs几乎可以分化成任何体细胞类型，包括 VSMCs和ECs(hiPSC-VSMCs和hiPSC-ECs)，这些细胞为获取血管提供了无限的细胞来源 细胞构建质量相当的TEVGs(hiPSC-TEVGs)。此外，通过工程表达 可以建立人类白细胞抗原(HLA)蛋白、非免疫原性或低免疫原性通用HiPSCs， 使HiPSC-TEVGs适合植入任何患者体内。通过利用HiPSC平台，TEVGS 对于血管创伤患者，可以大规模地开发，并且具有可预测性和可重复性 机械强度。此外，通过培养和冷冻保存同种异体通用HiPSC-ECs， 这些细胞可以立即应用于TEVGs的内皮化，用于小直径血管介入。vbl.使用 HIPSC-VSMCs，我们已经成功地研制出机械强度接近于 大隐静脉是血管损伤修复中常见的天然移植物。因此，要实现这一未来的应用 对于HiPSC-TEVGs，至关重要的是建立有效地去细胞HiPSC-TEVGs的方法， 一层管腔的HiPSC-ECs，并在体内评估随后的机械性能的临床前疗效 在这项提案中有详细说明。

Patients who have undergone vascular trauma resulting from penetrating (e.g. blast injury) or blunt (e.g. fracture and contusion from a traffic accident) trauma often experience severe damage to their small-diameter peripheral arteries (2-4mm, e.g. tibial or brachial arteries) and require surgical intervention to bypass or replace the injured vessel segments. As the accessibility of saphenous veins may be low in patients of vascular trauma due to severe injuries or loss of more than one lower extremity as a result of blast injury or severe traffic accident, and the application of synthetic vascular grafts can be hindered by the potential risk of infection due to the contagious nature of these types of injuries, an alternative source of vascular graft is in dire need. Acellular tissue engineered vascular grafts (TEVGs) therefore may offer a readily available treatment for emergency care for patients of vascular trauma. Although TEVGs of significant mechanical strength can be developed from culturing primary human vascular smooth muscle cells (VSMCs) followed by decellularization, this platform has several obstacles which prevent it from ultimately serving victims of vascular trauma. The finite expandability, limited accessibility, and donor-to-donor functional variations among primary VSMCs may hinder the efficiency of TEVG production. Further, as small-diameter TEVGs require autologous endothelial cell (EC) coating prior to implantation to avoid blood clothing, potential dysfunction of patient ECs due to either advanced age or disease, as well as the significant time required to derive and expand the patient's autologous ECs, could prevent applicability in treating acute vascular injury. Human induced pluripotent stem cells (hiPSCs), self-renewable cells derived from somatic cells by the ectopic expression of stem cell factors, provide an excellent alternative to address the complications of primary cell based TEVGs. As hiPSCs can be differentiated into virtually any somatic cell type, including VSMCs and ECs (hiPSC-VSMCs and hiPSC-ECs), these cells provide an unlimited cell source to obtain vascular cells to construct TEVGs of comparable quality (hiPSC-TEVGs). Further, by engineering the expression of human leukocyte antigen (HLA) proteins, non- or low-immunogenic universal hiPSCs could be established, making the hiPSC-TEVGs suitable for implantation into any patient. Through utilizing the hiPSC platform, TEVGs for patients of vascular trauma can be developed on a massive scale, and of predictable and reproducible mechanical strength. Additionally, through developing and cryopreserving allogeneic universal hiPSC-ECs, these cells could be immediately applied to endothelialize TEVGs for small-diameter vascular intervention. Using hiPSC-VSMCs, we have successfully developed TEVGs with mechanical strength approaching that of saphenous veins, the common native grafts in vascular injury repair. Therefore, to achieve this future application of hiPSC-TEVGs, it is essential to establish the approach to efficiently decellularize the hiPSC-TEVGs, provide a luminal layer of hiPSC-ECs, and assess subsequent mechanical properties in vivo for preclinical efficacy as detailed in this proposal.