Recellularization mechanisms in mononuclear cell seeded tissue engineered valves

 描述(由申请人提供)：虽然组织工程学为许多疾病提供了改善临床治疗的前景，但在实现这一潜力之前，必须克服限制实验室成功转化为临床实践的障碍。组织工程心脏瓣膜(TEHV)也是如此，这是一种活的、正在生长的瓣膜替代品，将显著改善儿童先天性心脏病和成人退行性瓣膜疾病的治疗。然而，科学和监管方面的挑战限制了以前心脏瓣膜组织工程策略的实用性和吸引力。使用非一次性或患者特定的复杂生物反应器系统带来了必须克服的重大监管障碍。我们已经解决了这个问题，通过开发一种用于心脏瓣膜接种和调节的完全一次性、一次性的生物反应器，允许研究临床上可行的TEHV处理策略。支架的安全性也是一个主要问题，因为植入的结构必须从植入时起就完全起到瓣膜的作用。这种担忧可以通过使用脱细胞心脏瓣膜支架来缓解，这种支架有临床安全性的记录；然而，以前在脱细胞心脏瓣膜叶中引入亚表面细胞的困难抑制了人们对这种特殊的TEHV支架的热情。使用我们定制的生物反应器，我们克服了这一限制，成功地在该传单中创建了骨髓单个核细胞(BM-MNC)的试验性群体。该项目的目的是通过扩展的生物反应器处理来确定该试验性BM-MNC群体体外成熟的可能性，并评估随后对种子组织的体外炎症反应。为实现这些目标制定了两个具体目标。在第一个目标中，将利用扩展的生物反应器处理来确定试验BM-MNC群体在培养期间的增殖和分化程度。我们还将评估脱细胞支架改建的可能性。目的2将利用体外巨噬细胞细胞因子信号分析来评估对种植组织的炎症反应。这两个特定目标的实现将在心脏瓣膜组织工程的背景下阐明去细胞心脏瓣膜的再细胞化机制。

 DESCRIPTION (provided by applicant): While tissue engineering offers the promise of improved clinical treatment for numerous disorders, obstacles that have limited the translation of laboratory successes into clinical practice must be overcome before this potential is realized. This holds true for the tissue engineered heart valve (TEHV), a living, growing valve substitute that would significantly improve the treatment of congenital heart disorders in children and degenerative valve disorders in adults. However, scientific and regulatory challenges limit the practicality and attractiveness of previous heart valve tissue engineering strategies. The use of complex bioreactors systems that are not disposable or patient-specific introduces a substantial regulatory obstacle that must be overcome. We have addressed this issue through the development of a fully disposable, single-use bioreactor for heart valve seeding and conditioning, permitting the investigation of clinically feasible TEHV processing strategies. Scaffold safety is also of major concern, as the implanted construct must be fully functional as a valve from the time of implantation forward. This concern can be mitigated through the use of decellularized heart valve scaffolds, which have a record of clinical safety; however, previous difficulties in introducing sub-surface cells into the leaflet of the decellularized heart valve hae dampened enthusiasm for this particular TEHV scaffold. Using our custom bioreactor, we have overcome this limitation, successfully creating a pilot population of bone marrow mononuclear cells (BM-MNCs) within the leaflet. The objectives of this project are to determine the potential for ex vivo maturation of this pilot BM-MNC population through extended bioreactor processing and to evaluate the subsequent in vitro inflammatory response to the seeded tissue. Two Specific Aims have been formulated to accomplish these objectives. In the first Aim, extended bioreactor processing will be utilized to determine the extent to which the pilot BM-MNC population proliferates and differentiates during the culture period. We will also evaluate the potential for remodeling of the decellularized scaffold. Aim 2 will utilize an in vitro macrophage cytokine signaling assay to assess the inflammatory response to the seeded tissue. Accomplishing these two Specific Aims will elucidate the recellularization mechanisms of the decellularized heart valve in the context of heart valve tissue engineering.