Influences of Lymph Flow on the Lymphatic Pump

描述（由申请人提供）：淋巴系统在正常的身体功能中起着许多作用。它是体液和大分子稳态、脂质吸收和淋巴细胞循环的关键组分。为了完成这些任务，淋巴系统必须调节淋巴循环。淋巴管通常逆着压力梯度输送淋巴及其组分。它通过主动和被动淋巴泵和带瓣血管的参与来实现。许多淋巴细胞具有自发的周期性血管扩张活性，这对淋巴液流动的产生很重要。这种活跃的淋巴泵可以以类似于心动周期的方式进行分析。可以确定淋巴压、压力变化率、直径、直径变化率、收缩频率、射血分数、每搏输出量、流量，以分析淋巴收缩功能。已知许多外在因素影响活跃的淋巴泵，如神经递质、体液因子和炎症产物。淋巴管固有的影响，如跨壁压也已知会影响主动淋巴泵。然而，另一个重要的内在因素，流量的影响还不清楚。在正常淋巴功能期间，淋巴流动表现出复杂的模式，其表现出幅度的巨大变化以及方向的瞬时变化。如果淋巴收缩活动对剪切敏感，则淋巴流不仅是淋巴泵的主要结果，而且也可能是对这些血管的反馈影响。尽管流动对淋巴管收缩性的影响具有潜在的重要性，但只有少数报道表明施加的流动对活性淋巴泵的影响。我们已经表明，在孤立的淋巴管中，通过控制增加强加的流量，可以抑制收缩的幅度和频率。其他研究表明，由于流量增加，在离体大鼠髂动脉微血管中，收缩频率增加，淋巴管直径减小，收缩幅度减小。因此，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，关于流体力学中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.