Influences of Lymph Flow on the Lymphatic Pump

描述（由申请人提供）：淋巴系统在体液循环、大分子稳态、脂肪吸收和免疫中起重要作用。 水肿是一种常见的淋巴功能障碍，表现为弥散性，并导致显著的发病率。淋巴水肿可能与长时间的淋巴液流动增强有关。 到目前为止，关于流动介导的淋巴反应及其影响的信息非常有限。 因此，研究调节淋巴液流动的机制对于发现水肿的发病机制和有效治疗至关重要。 该提案的总体目标是研究淋巴流量对淋巴收缩功能的影响，并评估这些影响所涉及的机制。 拟开展的研究主要集中在：1）定性和定量评价不同条件下原位淋巴管中淋巴流和淋巴速度的模式和大小。 我们将在对照条件下以及通过低渗容量输注增强淋巴形成/流动期间测量大鼠肠系膜淋巴管的淋巴直径、淋巴压和速度。 在这些研究中将使用伺服零微压力，光学测速和视频定格技术。2)研究孤立淋巴管中血流介导的淋巴管收缩功能改变的定量和时间模式。 我们将确定所需的压力分布在孤立的淋巴，以模拟在原位观察到的淋巴压力和速度的范围，然后评估的时间模式的流量介导的影响淋巴收缩泵功能的各个方面在几分钟到几个小时的过程。 计算机伺服控制泵和乳胶微球（直径约5 μ m）纳入灌注系统将用于控制淋巴压力和速度。 3)研究细胞和分子机制，负责对淋巴收缩功能的流量的影响。 在孤立的淋巴实验中，我们将验证是否流量介导的事件是依赖于一个完整的内皮。 然后，研究将集中在3个可能的内皮依赖性途径（一氧化氮，前列腺素类和内皮依赖性超极化因子）的流量介导的反应的血管紧张素。 将使用这3种途径的各种阻断剂进行研究，以确定这些途径是否以及在多大程度上可能参与血流介导的淋巴收缩功能改变。 这些实验的终点将包括测量分离的淋巴管中淋巴管内皮细胞和肌细胞的细胞内钙以及淋巴压、流量、速度、剪切力、壁张力和淋巴直径。

DESCRIPTION (provided by applicant): The lymphatic system plays important roles in body fluid circulation, macromolecular homeostasis, fat absorption, and immunity. A common lymphatic dysfunction, lymphedema is diversely expressed, and results in significant morbidity. Lymphedema can be associated with the long periods of enhanced lymph flow. Until now, very limited information about flow-mediated lymphatic responses and their impact has been available. Thus investigation of the mechanisms regulating lymph flow is extremely important to ongoing attempts to discover the pathogenesis and the effective treatment of lymphedema. The general objectives of proposal are to investigate the effects of lymph flow on lymphatic contractile function and to evaluate the mechanisms involved in these effects. The proposed studies will focus on: 1) Qualitatively and quantitatively evaluate the patterns and magnitudes of lymph flow and velocity in lymphatics under differing conditions in situ. We will measure lymphatic diameter, lymph pressures and velocities in rat mesenteric lymphatics under control conditions as well as during periods of enhanced lymph formation/flow by hypotonic volumeinfusion. Servo-null micropressure, optical velocimetry and video freeze-frame techniques will be used in these studies. 2) Investigate the quantitative and temporal patterns of flow-mediated alterations in lymphatic contractile function in isolated lymphatics. We will determine the pressure profiles needed in the isolated lymphatic to simulate the range of lymph pressures and velocities observed in situ and then evaluate the temporal pattern of flow-mediated effects on various aspects of lymphatic contractile pump function over the course of minutes to hours. Computerized servo controlled pumps and latex microspheres (about 5 mu m diameter) incorporated into perfusion system will be used to control the lymph pressure and velocities. 3) Investigate the cellular and molecular mechanisms that are responsible for the effects of flow on lymphatic contractile function. In isolated lymphatic experiments we will verify if the flow-mediated events are dependent upon an intact endothelium. Studies will then focus on 3 likely endothelial-dependent pathways (nitric oxide, prostanoid, and endothelial-dependent hyperpolarization factor) of the flow-mediated responses of lymphatics. Studies will be conducted using various blockers of these 3 pathways to determine if and to what degree these pathways might be involved in flow-mediated alteration of lymphatic contractile function. Endpoints of these experiments will include measurement of intracellular calcium of lymphatic endothelial and muscle cells in isolated lymphatics as well as lymph pressure, flow, velocity, shear, wall tension and lymphatic diameter.