PHYSIOLOGY OF HUMAN LYMPHATIC CONTRACTILITY: A HISTORICAL PERSPECTIVE

Abstract

The lymphatic system is a transport system that has important roles in fluid/macromoleculehomeostasis, lipid absorption, metastasis and immune function. It accomplishes these roles viathe generation of a regulated lymph circulation which is dependent upon valves and pumps toovercome the normal fluid pressure gradients. Lymphatic contractility plays crucial roles in theregulation and generation of lymph transport. Whereas our understanding of lymphaticcontractility in humans is somewhat limited, a number of studies both in situ and in vitro haveprovided important insights into the presence and modulation of lymphatic contractility. Thesestudies have clearly demonstrated that lymphatic vessels from a number of different humantissues possess both tonic and phasic changes in contractility. These changes in contractility arepresumably involved in the generation and regulation of lymph flow. It has been shown thathuman lymphatic contractility can be influenced by a number of neural and humoral agents as ameans to control lymph transport. However our understanding of the physical and chemicalfactors which regulate both the spontaneous pumping activity and the vessel tone are morelimited. An understanding of the factors which regulate human lymph transport could providevaluable information on human biology that could be of benefit to the treatment and preventionof diseases.