A 3D porous media liver lobule model: the importance of vascular septa and anisotropic permeability for homogeneous perfusion

Abstract

The hepatic blood circulation is complex, particularly at the microcirculatory level. Previously, 2D liver lobule models using porous media and a 3D model using real sinusoidal geometries have been developed. We extended these models to investigate the role of vascular septa (VS) and anisotropic permeability.The lobule was modelled as a hexagonal prism (with or without VS) and the tissue treated as a porous medium (isotropic or anisotropic permeability). Models were solved using computational fluid dynamics.VS inclusion resulted in more spatially homogeneous perfusion.Anisotropic permeability resulted in larger z-velocity components compared to isotropy. A parameter study revealed that results are most sensitive to the lobule size and radial pressure drop. Our model provides insight into hepatic microhemodynamics, and suggests that inclusion of VS in the model leads to perfusion patterns that are likely to reflect physiological reality. The model has potential for applications to unphysiological and pathological conditions.

Modeling function–perfusion behavior in liver lobules including tissue, blood, glucose, lactate and glycogen by use of a coupled two-scale PDE–ODE approach

“…In Debbaut et al (2014), the authors stated that in order to achieve homogenous sinusoidal perfusion vascular septa must be available-however, the direct morphologic proof is missing. The study of Teutsch (2005) could fill the gap.…”

“…This leads to an anisotropic permeability since the permeability parallel to the sinusoids is much higher than normal to the sinusoids. In Debbaut et al (2014), the influence of the transverse isotropic permeability and the vascular septum (vascular surfaces between adjacent lobules where part of the blood enters Hall (2006). The hepatic microcirculation was observed with an optical device using the technique of Orthogonal Polarization Spectral (OPS) Imaging (Cytoscan, Cytometrics, Inc., Philadelphia, PA, USA).…”

Closed-Loop Lumped Parameter Modeling of Hemodynamics During Cirrhogenesis in Rats

“…In fact, the sinusoidal network was merely represented by a single resistor in this model (the last generation of HV). More accurate 3D models of healthy and cirrhotic circulation have been proposed by [13,14,18,49]. Coupling our lobe-specific closed-loop model to a more detailed model of the microcirculation may facilitate to gain a better understanding of the altering microcirculatory hemodynamics during cirrhogenesis.…”

“…Debbaut et al [12] performed image-based CFD simulations of the human sinusoidal 3D network, thereby characterizing the permeability of healthy hepatic lobules. The permeability tensor was subsequently used to develop a generic 3D liver lobule model based on porous media [13]. Similar simulations were conducted to quantify the permeability tensor of the human hepatic microcirculation in the case of cirrhosis [14].…”

Unraveling liver complexity from molecular to organ level: Challenges and perspectives

“…This requires suitable models of perfusion and flow (Debbaut et al, 2014;Ricken et al, 2010;Schwen et al, 2014;Siggers et al, 2014) that will be integrated with the spatial-temporal models, and at the body scale, the contribution of external influences, for example transport of material from extra-hepatic sources into the liver, that is usually addressed by compartment models (Krauss et al, 2012).…”