Laryngotracheal Reconstruction with Engineered Cartilage

项目摘要/摘要 严重的声门下狭窄，声带正下方的呼吸道变窄，是对 在美国，每年有近10%的早产儿接受插管治疗。严重情况下需要 喉-气管重建术，外科医生将环状软骨切开，并添加一块自体患者- 衍生的软骨可以扩张呼吸道，恢复正常的气流。然而，在儿童中，成功率是 低至50%，再狭窄发生率高，需要翻修手术。移植物的失败直接与缺乏 儿童足够大小的自体软骨，组织工程学已经被提出要发展 可供选择的儿童LTR移植选择。一些方法，包括我们以前的一些工作，已经 在生产功能性软骨方面是有效的，但构建匹配所需的总体时间框架 天然软骨的力学性能(24周)与临床移植(8周)不相容。 此外，目前的细胞来源，如扩增的自体软骨细胞和间充质干细胞 通常会导致组织肥大和钙化。我们的目标是设计一种新型的软骨 植入物由患者细胞填充，机械上可行，适合临床上的LTR 相关的时间框架。我们的方法使用具有90%以上孔隙率的微结构聚合物支架，并且 具有足够的机械性能和独特的孔结构，能够促进软骨的形成 干细胞。此外，软骨前体细胞被认为是一种快速增殖、高度 软骨细胞来源。为了利用这些细胞，我们开发了一种微创活组织检查程序 取耳软骨祖细胞(ECCs)。我们最重要的假设是，微结构 聚合物支架与ECCs结合将产生具有适当机械强度的软骨植入物， 尺寸，和表型稳定性的个性化，微创的LTR。我们建议确定 实现最大软骨生成的微观结构和特定的作用机制。容量 产生强健的软骨表型，潜在地比耳软骨细胞更好和更少 容易钙化的，也将进行研究。最后，从种植的内皮细胞中获得的工程化软骨 该微孔支架将在猪LTR模型上进行测试。我们预计，我们的发现将带来一个重大的 在治疗声门下狭窄方面的创新，为长期的临床前安全性研究和 儿童呼吸道重建术的临床转译。

PROJECT SUMMARY/ABSTRACT Severe subglottic stenosis, the narrowing of the airway just below the vocal folds, develops as a response to intubation in close to 10% of the > 20,000 premature births per year in the United States. Severe cases require laryngotracheal reconstruction (LTR), in which surgeons split the cricoid and add a piece of autologous patient- derived cartilage to expand the airway and restore proper airflow. However, in children, the success rate is as low as 50% with a high incidence of restenosis requiring revision surgery. Graft failure is tied directly to the lack of sufficiently sized autologous cartilage in the child, and tissue engineering has been proposed to develop alterative grafting options for pediatric LTR. Some approaches, including some of our previous work, have been effective in producing functional cartilage, but the overall timeframe required for the construct to match the mechanical properties of native cartilage (>24 weeks) is not compatible with clinical translation (<8 weeks). Furthermore, current cell sources such as expanded autologous chondrocytes and mesenchymal stem cells frequently result in hypertrophic and calcified tissue. Our objective is to engineer a new type of cartilage implant that is populated with patients’ cells, mechanically viable and suitable for LTR within a clinically relevant timeframe. Our approach uses a microstructured polymeric scaffold with over 90% porosity and sufficient mechanical properties and with a pore structure uniquely capable of enhancing chondrogenesis of stem cells. Furthermore, cartilage progenitor cells have been proposed as a rapidly proliferating, highly chondrogenic cell source. To harness these cells, we have developed a minimally invasive biopsy procedure to harvest ear Cartilage Progenitor Cells (eCPCs). Our overarching hypothesis is that the microstructured polymeric scaffold combined with eCPCs will create cartilage implants with suitable mechanical strength, dimensions, and phenotypic stability for personalized, minimally invasive LTR. We propose to identify the microstructure that achieves the maximum chondrogenesis and the specific mechanism of action. The capacity of eCPCs to produce a robust cartilage phenotype, potentially better than that of ear chondrocytes and less prone to calcification, will also be studied. Finally, the engineered cartilage derived from the eCPCs seeded in the microporous scaffold will be test in a porcine LTR model. We expect that our findings will introduce a major innovation in the treatment of subglottic stenosis, laying the basis for long term pre-clinical safety studies and clinical translation in airway reconstructive surgery in children.