Abstract:
The lymphatic system is a highly complex biological system that facilitates the drainage of
excess fluid in body tissues. In addition, it is an integral part of the immunological control
system. Understanding the mechanisms of fluid absorption from the interstitial space and
flow through the initial lymphatics is essential to treat several pathological conditions.
The main focus of this study is to model the lymphatic drainage from the interstitial space
computationally. The model has been developed to consider a 3D lymphatic network,
and biological data has been used to inform the creation of realistic geometries for the
lymphatic capillary networks. We approximate the interstitial space as a porous region
and the lymphatic vessel walls as permeable surfaces. The dynamics of the flow is approximated
by Darcy-Brinkman equation in the interstitium and the Stokes equation in the
lymphatic capillary lumen. The proposed model examines lymph drainage as a function
of pressure gradients. Also, the effects of interstitial and lymphatic wall permeabilities on
the lymph drainage and the solute transportation in the model have been examined. The
computational results are in accordance with the available experimental measurements.
In addition, the interstitium is a poroelastic medium. The interstitium undergoes deformation
due to filtration, and according to the physiological data, the interstitial fluid volume
is a function of interstitial pressure. The interstitial permeability depends on the interstitial
hydration. Hence, the interstitial permeability can be considered as a pressure-dependent
quantity. Using the Carman-Kozency correlation, we have introduced pressure-dependent
permeability into the interstitium, and the computational results are presented to portray
the influence of poroelastic properties.