Engineering Functional Lymphatic Networks in Vitro

描述(申请人提供)：这份为期两年的提案描述了功能性淋巴网络的发展以及它们在体外与人造真皮结构的整合。虽然已经开发了许多方法来形成适合于工程化组织灌流的微血管网络，但对于如何形成能够将多余的间质液体和蛋白质排出这些组织的结构还知之甚少。为了促进工程化血管构建中的淋巴功能，我们建议使用微流控胶原凝胶作为支架，并在体内操纵微环境条件以模拟自然淋巴引流条件。具体地说，在目标1中，我们打算研究跨壁压力和剪切力--淋巴循环中的两个极其微小的因素--如何影响体外功能成熟。然后，我们将使用一组优化的这些压力来形成包含血液和淋巴管微血管的混合结构，其中前者表现出紧密的屏障，而后者是漏水的。在目标2中，我们将整合这些设计参数，以形成适合排出1平方厘米皮肤组织的淋巴网络。这些网络将通过光刻方法形成，目标1中获得的条件将作为开发整个网络中淋巴功能的起点。这些构造物将包含一个独立的血管网络用于灌流。我们将确定淋巴管网络的几何形状如何提高其在基础和超滤条件下维持非水肿性状态的能力。我们期望拟议的工作将提供指导合理设计和工程淋巴网络功能的基本原则。这项工作将是向系统合成整合功能血液和淋巴管系统的真皮组织迈出的第一步。这项工作将研究如何构建淋巴管--将器官多余的液体排出的淋巴管。我们打算将这些血管结合到人造皮肤(真皮)中，并显示它们在完整的天然皮肤中的功能就像淋巴管一样。我们预计，这项工作将为工程化器官提供第一步，当移植到患者体内时，这些器官可以适当地排出。

DESCRIPTION (provided by applicant): This two-year proposal describes the development of functional lymphatic networks and their integration into artificial dermal constructs in vitro. While many methods have been developed to form microvascular networks suitable for perfusion of engineered tissues, much less is known about how to form structures that can drain these same tissues of excess interstitial fluid and proteins. To promote lymphatic function in engineered vascular constructs, we propose to use microfluidic collagen gels as scaffolds and to manipulate the microenvironmental conditions to mimic native lymphatic drainage conditions in vivo. Specifically, in Aim 1, we intend to examine how transmural pressure and shear stress - two factors that are extremely small in the lymphatic circulation - affect functional maturation in vitro. We will then use an optimized set of these stresses to form hybrid constructs that contain both blood and lymphatic microvessels, in which the former exhibits a tight barrier while the latter is leaky. In Aim 2, we will integrate these design parameters to form lymphatic networks suitable for draining a 1 cm2 area of dermal tissue. These networks will be formed by a lithographic method, and the conditions obtained in Aim 1 will serve as a starting point for the development of lymphatic function in entire networks. These constructs will contain an independent vascular network for perfusion. We will determine how the geometry of the lymphatic network promotes its ability to maintain a non-edematous state, both under basal and hyper-filtration conditions. We expect the proposed work to provide underlying principles that govern the rational design and function of engineered lymphatic networks. This work will serve as a first step towards the systematic synthesis of dermal tissue that integrates functional blood and lymphatic vascular systems. This work will study how to build lymphatic vessels - the vessels that drain organs of their excess fluids. We intend to incorporate these vessels into an artificial skin (dermis) and to show that they function as lymphatics do in intact, native skin. We anticipate that this work will provide a first step towards engineered organs that can drain properly when implanted into a patient.