The Functional Mechanical Properties Of The Mouse Pulmonary Heart Valve
Xinzeng Feng1, Yifei Liu2, Hao Liu1, Christopher Breuer3, David McComb2, Michael Sacks1.
1University of Texas at Austin, Austin, TX, USA, 2The Ohio State University, Columbus, OH, USA, 3Nationwide Children's Hospital, Columbus, OH, USA.
Genetically modified mouse animal model of heart valve disease provides an efficient platform to study heart valve disease and test potential treatments. However, mouse heart valves are less understood compared to other animal models due to their small size. In this study, we presented an integrated imaging/computational approach to estimate the functional nonlinear mechanical properties of mouse pulmonary valves (PV) based on the representative geometry of mouse PVs obtained at multiple transvalvular pressure (TVP).
Data Acquisition: PVs from thirteen 1-year old C57BL/6 mice were excised, hydrostatically pressurized (TVP = 0, 10, 20, 30mmHg) and chemically fixed before ÁCT imaging was performed on a Thermo Scientific HeliScan microscope. Data Analysis: Each mouse PV was manually segmented in Simpleware ScanIP and geometrically characterized (Figure 1a). The measured geometric quantities together with the NURBS-derived cross sectional profiles of the leaflets (Figure 1b) were used to develop a regularized geometric model for each individual PV. Combining all available mouse PV geometric models at the same TVP, we then derived a representative geometry of mouse PVs with consistency to all measured geometric information (Figure 1c). Computationally, we used a customized finite element program to simulate the closing of PVs and match the representative geometry at each TVP (Figure 1d). From optimization, we were able to estimate the effective nonlinear stress-strain behavior of mouse PV leaflets.
We were able to develop a consistent representative geometry for mouse PVs at different TVP. Our computational model also well matched the representative geometry at each TVP.
Our study provides the first estimate for the representative geometry and nonlinear mechanical properties of mouse PVs. The technique detailed here will facilitate the use of mouse models in the studies for congenital heart valve diseases.
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