Bicuspid valve aortopathy is associated with distinct patterns of matrix degradation



Chim, Ya Hua, Davies, Hannah, Mason, David ORCID: 0000-0002-8773-5274, Nawaytou, Omar, Field, Mark, Madine, Jillian ORCID: 0000-0001-9963-5871 and Akhtar, Riaz ORCID: 0000-0002-7963-6874
(2019) Bicuspid valve aortopathy is associated with distinct patterns of matrix degradation. The Journal of Thoracic and Cardiovascular Surgery.

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Abstract

Objective To explore the micromechanical, biochemical and microstructural differences between BAV-A (bicuspid aortic valve aneurysm) and TAV (tricuspid aortic valve) idiopathic degenerative aneurysm (DA), compared to normal aorta. Methods Aortic tissue was obtained from patients undergoing aneurysmal repair surgery (BAV-A; n=15 and DA; n=15). Control tissue was obtained from aortic punch biopsies during coronary artery by-pass graft surgery (CABG; n=9). Nanoindentation was used to determine the elastic modulus (E) on the medial layer. Glycosaminoglycan (GAG), collagen and elastin levels were measured using biochemical assays. Verhoeff Van Gieson-stained cross-sections were imaged for elastin microstructural quantification. Results E was over 20% higher for BAV-A relative to control and DA (signifying a loss of compliance). No significance difference between control and DA were observed. Collagen levels for BAV-A (36.9±7.4μg/mg) and DA (49.9±10.9μg/mg) were higher compared to the control (30.2±13.1μg/mg). GAG and elastin levels were not significant between the groups. Elastin segments were uniform throughout the control. Aneurysmal tissues had less elastin segments close to the intima and adventitia layers. Both BAV-A and DA had elastin segments compacted in the media, however, elastin segments were highly fragmented in DA. Conclusion BAV-A has a greater loss of aortic wall compliance relative to DA and the control. Although elastin levels were equal for all groups, spatial distribution of elastin provided a unique profile of matrix degradation for BAV-A. Elastin compaction within the media of BAV-A may have resulted from the altered haemodynamic pressure against the wall, which could explain for the stiffness of the tissue.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 03 Oct 2019 14:53
Last Modified: 29 Oct 2020 14:11
DOI: 10.1016/j.jtcvs.2019.08.094
Open Access URL: https://doi.org/10.1016/j.jtcvs.2019.08.094
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URI: http://livrepository.liverpool.ac.uk/id/eprint/3056908