Modelling the glycocalyx-endothelium-erythrocyte interaction in the microcirculation: a computational study

Area of Science:

• Computational fluid dynamics
• Biomedical engineering
• Hemodynamics

Background:

• Microvascular circulation involves complex interactions between blood components and vessel walls.
• Existing models often require complex computational frameworks, limiting their efficiency.
• The endothelial glycocalyx layer plays a crucial role in microvessel function but is challenging to model accurately.

Purpose of the Study:

• To present a novel, coarse-grained, single-framework Eulerian model for microvascular blood flow.
• To investigate the combined effects of endothelial cell shape, glycocalyx layer properties, and blood's particulate nature on flow dynamics.
• To provide a computationally efficient method for simulating microcirculatory hemodynamics.

Main Methods:

• Developed a fully coupled, single Eulerian computational framework for blood flow simulation.
• Modeled blood as a two-component fluid (plasma and deformable droplets) within a lattice Boltzmann method.
• Incorporated a coarse-grained endothelial glycocalyx layer with variable porosity and repulsive forces.
• Represented endothelial cells using a sub-lattice 'wavy wall' closure.

Main Results:

• The model successfully reproduced key microvessel flow features, including particulate deformability and the Fahraeus-Lindqvist effect.
• Simulations demonstrated the significant influence of endothelial cell wall undulation, glycocalyx compression/repulsion, and blood's particulate nature on flow properties.
• Quantified the impact of the glycocalyx layer on flow rate and wall shear stress variations.

Conclusions:

• The novel Eulerian model offers an efficient and accurate approach to simulating microvascular blood flow.
• Accurate modeling of the endothelial glycocalyx layer is essential for understanding microcirculatory hemodynamics.
• The study highlights the importance of considering the coupled effects of vessel wall morphology, glycocalyx, and blood composition.