Influences of Lymph Flow on the Lymphatic Pump

描述(申请人提供)：淋巴系统在正常的身体功能中有许多作用。它是维持体液和大分子动态平衡、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。淋巴管通常在压力梯度的作用下运输淋巴及其成分。它通过主动和被动淋巴泵和带瓣血管的参与来做到这一点。许多淋巴管已被证明具有自发的周期性血管运动活动，这已被证明是重要的淋巴流的产生。这种主动淋巴泵可以用类似于心脏周期的方式进行分析。淋巴压力、压力变化率、直径、直径变化率、收缩频率、射血分数、每搏输出量、流量，均可用于分析淋巴收缩功能。已知许多外在因素影响主动淋巴泵，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，也是已知的影响主动淋巴泵。然而，另一个重要的内在因素--流动的影响尚不清楚。淋巴流动在正常淋巴功能过程中表现出复杂的模式，表现为大小和方向的短暂变化。如果淋巴管收缩活动对剪切力敏感，则淋巴流量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的影响具有潜在的重要性，但关于施加流动对主动淋巴泵的影响的报道很少。我们已经显示了抑制收缩的幅度和频率，这是由于在分离的淋巴管中施加的流量的控制增加所引起的。其他研究表明，由于血流增加，分离的大鼠髂微淋巴管收缩频率增加，淋巴管直径缩小，收缩幅度降低。因此，目前还不清楚血流大小的变化是否和/或如何调节不同淋巴管的收缩能力。此外，关于淋巴管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.