Engineering a Self-assembled, multi-tissue Tracheal Replacement

摘要 目前还没有成功的治疗长段气管狭窄的方法，最常见的原因是 长时间插管或气管切开。现有的治疗方案不足以预防再狭窄 而且经常需要连续的手术。组织工程气管有潜力满足这一需求。一个 功能性气管置换必须(1)具有径向刚性，(2)具有血管化或鼓励性 血管化和(3)含有呼吸上皮以恢复开放的呼吸道，同时避免再狭窄， 细菌感染和缺血性坏死。这项提案寻求开发一种气管替代物， 通过将组织环融合到由多个细胞组成的复合组织管中来满足这些功能要求 类型与受控的、本地化的生长因子呈现，并评估其作为 兔在体气道缺陷模型中的气管置换。这项工作的假设是，一个多- 细胞型、无支架的新气管可以用重要的细胞组织和关键的 通过以时空受控的方式将生物活性因子递送到模块化组织单元的功能 由自我组装的人类细胞组成。通过利用自定义装配系统，我们将集成 组织环单元组成复合管状气管结构。具体地说，该提案旨在(1)设计 具有定义尺寸和所需机械性能的软骨环和管状结构 高密度培养的人骨髓间充质干细胞作为新气管内的放射状支持，(2)工程软骨预防血管 具有交替的软骨和血管组织环以支持血管的复合管结构 在新气管中形成，(3)在软骨管上设计管腔上皮衬里，用于接口 与外部环境的关系以及(4)测试工程气管恢复呼吸道的能力 动物缺陷模型中的功能。这项工作试图设计出一种替代人类气管的方法 在体内植入时支持血管化和上皮化的放射状刚性。这种自下而上的自我 结合局部生物活性因子呈现的组合式高细胞密度策略是一种新颖的模块化方法 为慢性阻塞性肺疾病患者设计一种多组织、功能恢复的呼吸系统器官 巨大的、目前无法治愈的气管缺陷。这一平台技术也有可能成为 用于在体内再生其他复杂的组织和器官。

Abstract There is currently no successful treatment for long-segment tracheal stenosis, most commonly a result of prolonged intubation or tracheostomy. Available treatment options are inadequate in preventing restenosis and often require successive surgeries. A tissue engineered trachea has the potential to fill this need. A functional tracheal replacement must (1) have radial rigidity, (2) be vascularized or encourage vascularization and (3) contain respiratory epithelium to restore an open airway while avoiding restenosis, bacterial infections and ischemic necrosis. This proposal seeks to develop a tracheal replacement with these functional requirements by fusing tissue rings into a composite tissue tube comprised of multiple cell types with controlled, localized growth factor presentation, and to evaluate its ability to serve as a tracheal replacement in a rabbit airway defect model in vivo. The hypothesis of this work is that a multi- cell type, scaffold-free neotrachea can be engineered with vital cellular organization and critical functionality by delivering bioactive factors in a spatiotemporally controlled manner to modular tissue units comprised of self-assembled human cells. By utilizing a custom assembly system, we will integrate the tissue ring units into a composite tubular tracheal construct. Specifically, the proposal aims to (1) engineer cartilaginous ring and tubular structures with defined dimensions and requisite mechanical properties using high-density hMSC culture to serve as radial support in the neotrachea, (2) engineer cartilage-prevascular composite tubular constructs with alternating cartilage and vascular tissue rings to support blood vessel formation in the neotrachea, (3) engineer a luminal epithelial lining on cartilaginous tubes for interfacing with the external environment and (4) test the capacity of the engineered tracheas to restore airway functionality in an animal defect model. This work seeks to engineer a replacement human trachea with radial rigidity that supports vascularization and epithelialization when implanted in vivo. This bottom-up, self- assembled high-cell density strategy with localized bioactive factor presentation is a novel, modular approach to engineer a multi-tissue, function-restoring organ of the respiratory system for patients suffering from large and currently untreatable tracheal defects. This platform technology also has the potential to be employed to regenerate other complex tissues and organs in the body.