Development and assessment of a natural bio scafold for vascular reconstruction

描述(申请人提供)：小直径血管移植失败的原因有很多。显然，工作中的移植物必须包括细胞成分，因为惰性材料无法与周围组织适当地相互作用。人体对植入材料的反应是通过启动一系列复杂的生物反应来实现的，这些反应大致分为血栓、免疫原性和增生性反应。事实上，即使移植物含有细胞成分，这些负面的生物反应也会发生，导致移植物失败。我们的假设是，是组织工程化血管移植物的细胞成分无法做出适当的反应，从而导致移植物失败。因此，确定和测量改善移植物性能所需的内皮细胞和平滑肌细胞(SMC)功能的特定方面是至关重要的。在过去的几年里，我们的实验室已经开发了几种创新的方法来开发小直径组织工程血管。我们使用脱细胞的人脐静脉(Huv)作为可改建的支架。这种支架与组织机械隔离，形成具有统一机械性能的长管状支架。我们开发了一种水凝胶“收缩包裹”技术，可以将高密度的人SMC快速种植到血管的开通表面。这些初步调查表明，Huv脚手架具有很好的改建能力。我们这个项目的目标是将HUV完全发展为小直径血管，然后表征和定义导致细胞表型的条件，将对血栓形成和炎症信号的不适当反应降至最低。我们的具体目标是：1)全面评估人脐静脉(HUV)支架是否具有有利于早期平滑肌细胞再生的环境。2)确定促进人内皮细胞在HUV支架管腔上附着、生长和功能(体内类似)的条件。3)测试流体机械环境的细节在使内皮细胞采用最大限度地减少血栓形成和炎症反应的表型方面至关重要的假设。4)检验假设，即将平滑肌细胞暴露在低氧条件下不会严重损害全氧内皮细胞的功能 我们的目标是开发用于心脏和外周血管重建的功能性血管。独一无二的 采用的方法是使用从人脐静脉中提取的生物支架，这些人脐静脉是从 脐带，以产生机械均匀，生物相容的材料。建议进行的调查 这里的目的是定义促进血管壁再生以赋予生物功能的条件。 此外，我们将研究调节不良细胞功能的参数，如伤口愈合 相信，这种使用人脐静脉的独特方法与这里描述的技术相结合， 可以开发出可行的替代方案来缓解这种临床需求。

DESCRIPTION (provided by applicant): Numerous factors have contributed to the failure to produce a successful small diameter vascular graft. It is clear that a working graft must include a cellular component since inert materials are unable to interact appropriately with the surrounding tissue. The body responds to implanted materials by initiating a complex series of biological reactions, broadly grouped as thrombotic, immunogenic and hyperplastic responses. In fact, even with grafts that include a cellular component, these negative biological responses occur leading to graft failure. It is our hypothesis that it is the inability of the cellular component of a tissue engineered vascular graft to respond appropriately that leads to graft failure. Therefore it is essential to define and measure specific aspects of endothelial and smooth muscle cell (SMC) function that are required to improve graft performance. Over the last several years, our laboratory has developed several innovative approaches for the development of a small diameter tissue engineered blood vessel. We use a decellurized human umbilical vein (HUV) as a remodelable scaffold. This scaffold is mechanically isolated from the tissue resulting in a long, tubular scaffold with uniform mechanical properties. We have developed a hydrogel 'shrink-wrapping' technique for rapidly seeding high densities of human SMC onto the abluminal surface of the vessel. These preliminary investigations have shown the HUV scaffold to have an excellent capacity to remodel. Our goal with this project is to fully develop the HUV as a small diameter blood vessel, then characterize and define conditions leading to a cell phenotype that minimizes inappropriate responses to thrombogenic and inflammatory signals. Our specific aims are 1) comprehensively assess the human umbilical vein (HUV) scaffold as an environment favorable for early regenerative events of smooth muscle cells. 2) Identify conditions promoting attachment, growth, and function (in vivo-like) of human endothelial cells on the lumen of the HUV scaffold. 3) Test the hypothesis that details of the fluid mechanical environment are critical in causing endothelial cells to adopt a phenotype that minimizes thrombosis and an inflammatory response. 4) Test the hypothesis that exposing the smooth muscle cells to hypoxic conditions does not severely impair the function of the fully oxygenated endothelial cells Narrative Our aim to develop functional blood vessels for cardiac and peripheral vascular reconstruction. A unique approach is taken using a bioscaffold derived from the human umbilical veins that have been ¿machined¿ from umbilical cords to yield a mechanically uniform, biologically compatible material. The investigations proposed herein aim to defined conditions that promote regeneration of the vascular wall to confer biological functionality. Further, we will investigate parameters that modulate undesirable cell function, such as wound healing We believe, this unique approach using the human umbilical vein in concert with technologies described herein, a viable alternative can be developed to alleviate this clinical demand.