Influences of Lymph Flow on the Lymphatic Pump

描述（申请人提供）：淋巴系统在正常身体功能中有许多作用。它是体液和大分子稳态、脂质吸收和淋巴细胞循环的关键成分。为了完成这些任务，淋巴系统必须调节淋巴循环。淋巴管通常沿压力梯度输送淋巴液及其成分。它是通过主动和被动淋巴泵和有瓣血管的参与来实现的。许多淋巴管已被证明具有自发的周期性血管舒缩活动，这已被证明是重要的产生淋巴流。这种活跃的淋巴泵可以用类似于心脏周期的方式来分析。淋巴压力，压力变化率，直径，直径变化率，收缩频率，射血分数，行程体积，流量，可以确定分析淋巴收缩功能。已知许多外在因素会影响活跃淋巴泵，如神经递质、体液因子和炎症产物。淋巴管固有的影响，如跨壁压力，也会影响活性淋巴泵。然而，另一个重要的内在因素——流动的影响并不清楚。在正常淋巴功能中，淋巴流动表现出复杂的模式，其大小变化很大，方向也有短暂的变化。如果淋巴收缩活动对剪切敏感，那么淋巴液流动不仅是淋巴泵的主要结果，也可能是对这些血管的反馈影响。尽管流动对淋巴收缩性的影响具有潜在的重要性，但只有少数关于施加流动对主动淋巴泵的影响的报道。我们已经证明，在孤立的淋巴管中，通过控制施加流量的增加，可以抑制收缩的幅度和频率。其他研究显示，由于流量增加，离体大鼠髂微淋巴管收缩频率增加，淋巴管直径减小，收缩幅度减小。因此，目前尚不清楚流量大小的变化是否和/或如何调节不同淋巴管的收缩性。此外，关于淋巴管流动条件变化的影响的其他几个问题的答案也仍然不清楚。

DESCRIPTION (provided by applicant): The lymphatic system has many roles in normal body function. It is a key component to body fluid and macromolecular homeostasis, lipid absorption, and lymphocyte circulation. To accomplish these tasks the lymphatic system must regulate lymph circulation. The lymphatics normally transport lymph and its components against pressure gradients. It does so through the involvement of active and passive lymphatic pumps and valved vessels. Many lymphatics have been shown to possess spontaneous cyclical vasomotor activity, which has been shown to be important to the generation of lymph flow. This active lymph pump can be analyzed in a fashion analogous to the cardiac cycle. Lymph pressure, rate of pressure change, diameter, rate of diameter change, contraction frequency, ejection fraction, stroke volume, flow, can be determined to analyze lymphatic contractile function. Many extrinsic factors are known to influence the active lymph pump, such as neurotransmitters, humoral factors, and inflammatory products. Influences intrinsic to the lymphatic vessel such as transmural pressure are also known to influence the active lymph pump. However the effect of another important intrinsic factor, flow is not clear. Lymph flow exhibits a complicated pattern during normal lymphatic function that shows great changes in magnitude and also transient changes in direction. If the lymphatic contractile activity is sensitive to shear, lymph flow is not only the main result of the lymph pumps but it may also be a feedback influence on these vessels. In spite of the potential importance of the effects of flow on lymphatic contractility, there are only a few reports of the influence of imposed flow on an active lymph pump. We have shown an inhibition of the amplitude and frequency of contractions induced by a controlled increase in imposed flow in isolated lymphatic vessels. Others have shown increases in the contraction frequency, reductions in lymphatic diameters and decreases in the amplitude of contractions in isolated rat iliac microlymphatics as a result of increases in flow. So, it is not clearly understood if and/or how changes in the magnitude of flow can modulate the contractility of different lymphatic vessels. Additionally the answers to several more questions concerning the influence of changes in flow conditions in lymphatics are also still unclear.