HLS-Self-endothelializing off-the-shelf vascular grafts

摘要 HLS16-07-我们建议开发完全脱细胞的现成组织工程血管移植物(TEVG) 用于治疗心血管疾病。作为基础支架生物材料，我们将使用小肠 粘膜下层(SIS)，FDA批准用于其他医学适应症(Cook Biotech)。这些无细胞组织 工程移植物将利用结合到SIS和自身的肝素来实现抗血栓功能 结合肝素结合域的血管内皮生长因子(VEGF)内皮化。这个 目前TEVG的最先进技术包括在漫长的制造过程中进行预细胞化，这是 由于培养时间较长，涉及细胞扩增和生物反应器预适应。此外，单元格 从患有合并症的患者身上采集和随后的培养增加了TEVG制造的时间和风险。 一些现有的技术通过利用生物反应器培养来开发移植物来部分解决这个问题 同种异体细胞来源，然后在储存和植入前脱细胞。然而，7-10周 仍然需要培养时间，小直径的移植物也需要内皮化 患者在植入前自己的细胞，这是一个很大的限制。相比之下，我们的技术克服了 使用固定在移植物管腔内的肝素/血管内皮生长因子来传递抗血栓形成的主要局限性 属性以及吸引患者自己的细胞来填充移植物，从而消除了 细胞。在我们的初步研究中，这些移植物在绵羊颈动脉模型中进行了测试，在那里他们证明了 良好的通畅性，在术后1个月内在管腔内形成完全融合的内皮层 植入。在目前的提案中，我们的目标是开发这些用于儿科外科应用的脱细胞移植物。 通过在青春期绵羊生长模型中评估它们3个月和6个月来评估TEVG生长， 通畅性、重塑和功能。6个月的时间段大约相当于人类的5年(绵羊 寿命~8年)，在此期间动物的大小和体重翻了一番，因此，这是一种合适的 评估移植物生长、长期重塑和功能的时间。特异型脱细胞移植物的进一步检测 儿科应用将在第二阶段进行，以及储存、稳定性和无菌，这将提供 临床试验的“现成”产品。

ABSTRACT HLS16-07 - We propose to develop completely acellular off-the-shelf tissue engineered vascular grafts (TEVG) for the treatment of cardiovascular disease. As base scaffold biomaterial we will use small intestinal submucosa (SIS), FDA approved for other medical indications (Cook Biotech). These acellular tissue engineered grafts will be functionalized to be anti-thrombotic utilizing heparin bound to the SIS and self- endothelializing with vascular endothelial growth factor (VEGF) bound to the heparin-binding domain. The current state-of the-art for TEVG involves pre-cellularization in a lengthy manufacturing process, which is limiting due to long culture times involved in cell expansion and bioreactor pre-conditioning. Further, cell harvest and subsequent culturing from patients with comorbidities adds time and risk to TEVG manufacture. Some existing technologies partially address this problem by utilizing bioreactor culture to develop grafts from allogeneic cell sources, and then decellularizing them before storage and implantation. However, 7-10 weeks of culture time are still required and smaller diameter grafts also require the lumen to be endothelialized with the patients’ own cells prior to implantation, a significant limitation. In contrast, our technology overcomes these major limitations by using heparin/VEGF immobilized in the graft lumen to impart anti-thrombogenic properties as well as to attract the patients’ own cells to populate the graft, thereby eliminating the need for cells. In our preliminary studies, these grafts were tested in an ovine carotid model, where they demonstrated excellent patency and developed a completely confluent endothelial layer in the lumen within 1 month post implantation. In the current proposal, we aim to develop these acellular grafts for pediatric surgical applications by evaluating them in an adolescent ovine growth model for 3 and 6 months to evaluate TEVG growth, patency, remodeling and function. The 6 month time period is equivalent to about 5 human years (sheep lifespan ~ 8 years), during which the size and weight of the animals double and therefore, it is an appropriate time to evaluate graft growth, long-term remodeling and function. Further testing of acellular grafts for specific pediatric applications will be performed in Phase II, as well, storage, stability and sterility which will provide a “off-the-shelf” product for clinical trials.