Ex vivo experimental characterizations for understanding the interrelationship between tissue mechanics and collagen microstructure of porcine mitral valve leaflets.

Autor: Fitzpatrick DJ; Biomechanics & Biomaterials Design Lab, School of Aerospace & Mechanical Eng., University of Oklahoma, USA., Pham K; Biomechanics & Biomaterials Design Lab, School of Aerospace & Mechanical Eng., University of Oklahoma, USA., Ross CJ; Biomechanics & Biomaterials Design Lab, School of Aerospace & Mechanical Eng., University of Oklahoma, USA., Hudson LT; Biomechanics & Biomaterials Design Lab, School of Aerospace & Mechanical Eng., University of Oklahoma, USA., Laurence DW; Biomechanics & Biomaterials Design Lab, School of Aerospace & Mechanical Eng., University of Oklahoma, USA., Yu Y; Department of Mathematics, Lehigh University, USA., Lee CH; Biomechanics & Biomaterials Design Lab, School of Aerospace & Mechanical Eng., University of Oklahoma, USA. Electronic address: ch.lee@ou.edu.
Jazyk: angličtina
Zdroj: Journal of the mechanical behavior of biomedical materials [J Mech Behav Biomed Mater] 2022 Oct; Vol. 134, pp. 105401. Date of Electronic Publication: 2022 Aug 01.
DOI: 10.1016/j.jmbbm.2022.105401
Abstrakt: Unidirectional blood flow in the left side of the heart is regulated by the mitral valve. To better understand the mitral valve function, researchers have examined the structural and mechanical properties of the mitral valve leaflets; however, limitations of the previous studies include the use of mechanics- and structure-altering tissue modifications (e.g., optical clearing) that limit the ability to quantify the unique load-dependent reorientation and realignment of the collagen fibers as well as their interrelation with the valve tissue mechanics. Herein, we aimed to circumvent these limitations by utilizing an integrated polarized-light imaging and biaxial testing system for understanding the mechanics-microstructure interrelationship for porcine mitral valve leaflets. We further performed constitutive modeling and evaluated the accuracy of the affine fiber kinematics theory. From the tissue mechanics perspective, the posterior leaflet was more extensible in the radial direction than the anterior leaflet (14.2% difference in radial tissue stretch), while exhibiting smaller collagen and elastin moduli based on the determined constitutive model parameters. From the collagen microstructure's standpoint, the posterior leaflet had smaller increases in optical anisotropy (closely related to the degree of fiber alignment) than the anterior leaflet (32.8±7.7% vs. 50.0±19.7%). Further, the leaflets were found to possess two distinct fiber families - one family oriented along the circumferential tissue direction, and another more disperse family with a 30°-40° offset from the first fiber family. Finally, affine fiber kinematics consistently underpredicted the collagen fiber reorientations Overall, this study improved our understanding of the mitral valve leaflets that is essential for facilitating tissue-emulated valve replacement and cardiac valve modeling frameworks.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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