Modelling Lymph Propulsion in a 3D Model of Murine Collecting Vessel with Three Lymphangions in Series

Abstract

The lymphatic system maintains tissue homeostasis by transporting the excess fluid from the interstitium and ultimately returning it to the venous circulation against an adverse pressure gradient and gravitational force. The spontaneous contractions of lymphangions, the building blocks of collecting vessels, and the secondary lymphatic valves play key roles in lymph propulsion. The aim of this study was to investigate lymph propulsion in a series of three contracting lymphangions in a 3D reconstructed model segmented from micro-CT scans of the collecting lymphatics in the hind limb of mice. Computational Fluid Dynamics and Fluid–Structure Interaction were used to study the behavior of flow within the collecting vessel, as well as the behavior and deformations of the vessel wall and the poroelastic interstitium. The secondary valves were modelled as porous membranes with closed or open states depending on their permeability. A sensitivity study revealed that the parameters having the most impact on the total volume of lymph propelled by active contraction of the lymphangions were the elastic modulus of the interstitium and the permeability of the secondary valves during the open states.