Development of HLA engineered universal vascular grafts from human iPSCs

获得现成的小直径（2-4 mm）血管移植物是以下患者未满足的需求 外周动脉损伤或外周动脉粥样硬化。虽然假体或自体移植物可以 用于此目的，假体移植物中感染或血栓形成的潜在风险和有限的 由于疾病、既往使用或尺寸不匹配而引起的患者亚组中的自体血管可用性， 受伤的船只限制了它们的应用。脱细胞组织工程血管移植物（TEVG）来源于 人诱导多能干细胞（hiPSC）提供了自体或合成移植物的有希望的替代物。 这些hiPSC-TEVG可以由血管平滑肌细胞（VSMC）和内皮细胞（ECs）构建。 (ECs)来源于hiPSC，并且先前已显示具有与天然的HiPSC相当的机械性能。 临床旁路手术中使用的血管。hiPSC-TEVG提供了优于其他血管移植物的几个优点， 值得注意的是，hiPSC自我更新和分化成体内几乎每种细胞类型的能力允许其在体内生长。 可再生的来源，从中获得VSMC，以可再生地创建TEVG。关键的是，hiPSC-TEVG可以 可用于解决外周动脉的现成小直径血管移植物的未满足需求 损伤或动脉粥样硬化通过TEVG的脱细胞化随后内皮化。而非细胞 TEVG可以直接实施为较大直径的血管移植物，小直径的移植物需要血管移植物。 内皮细胞，以防止血管中的血栓形成。这一事实进一步增加了hiPSC技术的价值 这是因为成功地衍生出了用于此目的的低免疫原性的“通用”EC。低免疫原性 hiPSC是通过调节人白细胞抗原（HLA）的表达来产生的，以避免 通过宿主免疫系统的破坏，同时为小直径移植物提供健康的内皮。创作 和研究生物材料和细胞相互作用的机械鲁棒性，低免疫原性， 内皮化的hiPSC-TEVG形成了这一提议的基础，这里的成功将增加经济和 通过提高短期储存能力和达到可扩展的 患者人群。为了实现这一目标，将对低免疫原性， 通用EC分化以产生用于移植工程化的功能和机械稳健的EC。 还将产生脱细胞的、低免疫原性的内皮化hiPSC-TEVG，并且hiPSC-TEVG的生物相容性也将提高。 将评估血小板-和全血-管腔表面相互作用。此外，体内免疫相容性和 将在人源化大鼠主动脉间置移植物中评价通用hiPSC-TEVG的治疗功效 模型从这一提案中收集的信息将表明普遍适用的 hiPSC-TEVG技术，并为未来非人灵长类动物，并最终临床利用铺平道路 这些移植物用于外周动脉损伤或动脉粥样硬化的患者。

Access to readily available small diameter (2-4 mm) vascular grafts presents an unmet need to patients following peripheral arterial injury or peripheral arterial atherosclerosis. Although prosthetic or autologous grafts could be utilized for this purpose, the potential risk of infection or thrombus formation in prosthetic grafts and the limited autologous vessel availability in a subset of patients arising from disease, prior utilization, or size mismatch to the injured vessel restricts their application. Acellular tissue engineered vascular grafts (TEVGs) derived from human induced pluripotent stem cells (hiPSCs) provide a promising alternative to autologous or synthetic grafts. These hiPSC-TEVGs can be constructed from vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) derived from hiPSCs and have previously been shown to have mechanical properties comparable to native vessels used in clinical bypass surgeries. hiPSC-TEVGs offer several advantages over other vascular grafts, notably the ability for hiPSCs to self-renew and differentiate into almost every cell type in the body allows for a replenishable source from which to derive VSMCs to reproducibly create TEVGs. Critically, hiPSC-TEVGs could be utilized to address the unmet needs of readily available small diameter vascular grafts for peripheral arterial injury or atherosclerosis through decellularization followed by endothelialization of the TEVG. Whereas acellular TEVGs could directly be implemented as larger diameter vascular grafts, small diameter grafts require an endothelium to prevent thrombosis in the vessel. This fact further increases the value of the hiPSC technology due to the successful derivation of hypoimmunogenic, “universal” ECs for this purpose. Hypoimmunogenic hiPSCs are created through modulating the expression of human leukocyte antigens (HLAs) so as to avoid destruction by the host immune system, while providing a healthy endothelium to small diameter grafts. Creation and investigation of the biomaterial and cellular interactions of mechanically robust, hypoimmunogenic, endothelialized hiPSC-TEVGs forms the basis of this proposal, and success here will increase the economic and practical impact of the product through enhancing short term storage capability and reaching an expansive patient populace. In pursuit of this, expansive validation and characterization will be done on hypoimmunogenic, universal EC differentiation to produce functionally and mechanically robust ECs for graft engineering. Decellularized, hypoimmunogenic endothelialized hiPSC-TEVGs will also be generated and biocompatibility of platelet- and whole blood-luminal surface interactions will be assessed. Further, in vivo immunocompatibility and therapeutic efficacy of universal hiPSC-TEVGs will be evaluated in a humanized rat aortic interposition graft model. Information gleaned from this proposal will demonstrate the diversity and practicality of the universal hiPSC-TEVG technology, and pave the way for future non-human primate, and ultimately clinical utilization of these grafts for patients with peripheral arterial injury or atherosclerosis.