Abstract: SA-PO036
Computational Fluid Dynamics Modeling (CFD) of Wall Strain in a Murine Glomerular Capillary Segment
Session Information
- Engineering-Based Approaches to Problems in Nephrology
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Bioengineering
- 300 Bioengineering
Authors
- Fissell, William Henry, Vanderbilt University, Nashville, Tennessee, United States
- Davenport, John Bernard, University of Manchester, Manchester, United Kingdom
- Goodin, Mark S., SimuTech Group, Hudson, Ohio, United States
- Lennon, Rachel, University of Manchester, Manchester, United Kingdom
Background
Mechanical forces such as pressure and stress in the glomerular capillary tuft have been proposed to mediate hyperfiltration and podocyte injury and detachment, leading to irreversible glomerular disease. However, the actual forces imposed by blood flow in the tuft are incompletely defined. Simple tube models poorly capture the complex anatomy of the tuft. We undertook to model fluid flow through an actual capillary tuft to understand the feasibility of applying CFD to glomerukar physiology.
Methods
Mouse kidneys were cut into 1 mm cubes and fixed wiht glutaraldehyde and prepared for electron microscopy with osmium. Tissue was mounted onto an aluminim cryo pin using cyanoacrylate and all block surfaces trimmed. A gold coating was applied to the block to create a conductive surface. The block was placed in the Quanta 250 FEG/Gatan 3view system and a 41 x 41 field of view was imaged at an approximate pixel size of 10 nm and section thickness of 50 nm.
MIMICS (Materialise, Ann Arbor, MI) image reconstruction software was used to create a 3D surface representation of the capillary segment. The flow through the capillary segment was then modeled using ANSYS-Fluent (ANSYS, Canonsburg, PA) CFD software. Steady-state, laminar flow conditions were modeled and a pressure differential across the section was applied to provide the desired velocities within the capillary lumen. Estimates of desired fluid velocity in the capillary were drawn from 2-photon intravital microscopy experiments.
Results
The CFD solution predicted values of fluid shear stress, fluid streamlines, and wall strain along the glomerular capillary segment.
Conclusion
End-to-end estimation of physical forces at the glomerular capillary wall is possible by computational modling of flow through structures imaged via serial block section EM. Further work is needed to capture unsteady flow and the influence of blood cells on local wall strain.
Funding
- Clinical Revenue Support