title: An Image-Based Model of Fluid Flow Through Lymph Nodes.
abstract: The lymphatic system returns fluid to the bloodstream from the tissues to maintain tissue fluid homeostasis. Lymph nodes distributed throughout the system filter the lymphatic fluid. The afferent and efferent lymph flow conditions of lymph nodes can be measured in experiments; however, it is difficult to measure the flow within the nodes. In this paper, we present an image-based modelling approach to investigating how the internal structure of the node affects the fluid flow pathways within the node. Selective plane illumination microscopy images of murine lymph nodes are used to identify the geometry and structure of the tissue within the node and to determine the permeability of the lymph node interstitium to lymphatic fluid. Experimental data are used to determine boundary conditions and optimise the parameters for the model. The numerical simulations conducted within the model are implemented in COMSOL Multiphysics, a commercial finite element analysis software. The parameter fitting resulted in the estimate that the average permeability for lymph node tissue is of the order of magnitude of [Formula: see text]. Our modelling shows that the flow predominantly takes a direct path between the afferent and efferent lymphatics and that fluid is both filtered and absorbed across the blood vessel boundaries. The amount that is absorbed or extravasated in the model is dependent on the efferent lymphatic lumen fluid pressure.
authors.affiliation: Faculty of Engineering and the Environment, University of Southampton, Highfield Campus, Southampton, SO17 1BJ, UK. laura.cooper@soton.ac.uk.|Institute for Life Sciences, University of Southampton, Southampton, UK. laura.cooper@soton.ac.uk.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Cooper
authors.affiliation: Faculty of Engineering and the Environment, University of Southampton, Highfield Campus, Southampton, SO17 1BJ, UK.
authors.forename: James P
authors.initials: JP
authors.lastname: Heppell
authors.affiliation: Faculty of Medicine, Southampton General Hospital, University of Southampton, Southampton, SO16 6YD, UK.|Institute for Life Sciences, University of Southampton, Southampton, UK.
authors.forename: Geraldine F
authors.initials: GF
authors.lastname: Clough
authors.affiliation: Faculty of Engineering and the Environment, University of Southampton, Highfield Campus, Southampton, SO17 1BJ, UK.|Institute for Life Sciences, University of Southampton, Southampton, UK.
authors.forename: Bharathram
authors.initials: B
authors.lastname: Ganapathisubramani
authors.affiliation: Faculty of Engineering and the Environment, University of Southampton, Highfield Campus, Southampton, SO17 1BJ, UK.|Institute for Life Sciences, University of Southampton, Southampton, UK.
authors.forename: Tiina
authors.initials: T
authors.lastname: Roose
mesh_terms: D000818:Animals; D020342:Finite Element Analysis; D006706:Homeostasis; D007091:Image Processing, Computer-Assisted; D008196:Lymph / Q000502:physiology*; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000502:physiology*; D042601:Lymphatic Vessels / Q000502:physiology; D055641:Mathematical Concepts; D051379:Mice; D008954:Models, Biological; D012984:Software
keywords: Finite element modelling; Image-based modelling; Lymph nodes; Porous media