Engineering Functional Lymphatic Networks in Vitro

描述（由申请人提供）：这个为期两年的提案描述了功能性淋巴网络的发展及其在体外人工真皮结构中的整合。虽然已经开发了许多方法来形成适合工程组织灌注的微血管网络，但对于如何形成能够排出这些组织中多余的间质液和蛋白质的结构知之甚少。为了促进淋巴在工程血管结构中的功能，我们建议使用微流控胶原凝胶作为支架，并操纵微环境条件来模拟体内天然淋巴排水条件。具体来说，在目的1中，我们打算研究跨壁压力和剪切应力-两个在淋巴循环中非常小的因素-如何影响体外功能成熟。然后，我们将使用一组优化的这些应力来形成包含血液和淋巴微血管的混合结构，其中前者表现出紧密的屏障，而后者则是泄漏的。在Aim 2中，我们将整合这些设计参数，形成适合引流1 cm2面积的真皮组织的淋巴网络。这些网络将通过光刻方法形成，Aim 1中获得的条件将作为整个网络中淋巴功能发展的起点。这些结构将包含一个独立的血管网络进行灌注。我们将确定淋巴网络的几何形状如何促进其在基础和超滤条件下维持非水肿状态的能力。我们期望所提出的工作能够提供支配工程淋巴网络的合理设计和功能的基本原则。这项工作将作为系统合成真皮组织的第一步，整合功能性血液和淋巴血管系统。这项工作将研究如何建立淋巴管——排泄器官多余液体的血管。我们打算将这些血管整合到人造皮肤（真皮层）中，并证明它们的功能与完整的天然皮肤中的淋巴管一样。我们预计这项工作将为移植到病人体内后能够正常排出的工程器官迈出第一步。

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.