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Macro- and Micro-mechanical Properties of the Ovine Aorta: Correlation with Regional Variations in Collagen, Elastin and Glycosaminoglycan Levels

Artery Research volume 25, pages 27–36 (2019)Cite this article

Abstract

Aortic diseases are a significant cardiovascular health problem and occur in different ways across the vascular tree. Investigation of the mechanical properties of the aorta is important for better understanding of aortic diseases. In this study, the biomechanical and biochemical properties of the ovine aorta have been comprehensively mapped across different regions from the ascending to the abdominal aorta. We have determined the mechanical properties at the macro- (via tensile testing) and at the micro-scale (via oscillatory nanoindentation). Uniaxial tensile testing was conducted on circumferential strips for the ascending, upper thoracic region and upper abdominal region to determine physiological elastic modulus, tangent modulus at 0.5 strain, and the maximum elastic modulus. Nanoindentation was conducted on the medial layer (tissue cross-section) and intimal and adventitial face (longitudinal orientation) to determine the shear storage (G′) and shear loss modulus (G″). All of the measured mechanical properties increased with distance from the heart. For example, G′ increased by 237.1% and 275.3% for the intimal face and adventitial face, respectively. In parallel, collagen, glycosaminoglycans (GAG) and elastin levels were also measured across the entire length of the ovine aorta. The mechanical properties correlated with increasing collagen, and decreasing GAG and elastin. Collagen increased by 147.2% whereas GAG (−120.3%) and elastin decreased (−78.2%). These findings have relevance for developing mechanistic insight into aortic aneurysms and dissections.

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Authors and Affiliations

  1. Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, The Quadrangle Brownlow Hill, Liverpool, L69 3GH, UK

    Phakakorn Panpho, Ya Hua Chim & Riaz Akhtar

  2. Faculty of Science and Technology, Pibulsongkram Rajabhat University, Phitsanulok, 65000, Thailand

    Phakakorn Panpho

  3. Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L69 3BX, UK

    Brendan Geraghty

  4. Liverpool Centre for Cardiovascular Sciences, University of Liverpool, Liverpool, UK

    Hannah A. Davies, Mark L. Field, Jillian Madine & Riaz Akhtar

  5. Institute of Integrative Biology, University of Liverpool, Biosciences Building, Liverpool, L69 7ZB, UK

    Hannah A. Davies & Jillian Madine

  6. Department of Cardiac Surgery, Liverpool Heart and Chest Hospital, Thomas Drive, Liverpool, L14 3PE, UK

    Mark L. Field

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  1. Phakakorn Panpho
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  2. Brendan Geraghty
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  7. Riaz Akhtar
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Correspondence to Riaz Akhtar.

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Peer review under responsibility of the Association for Research into Arterial Structure and Physiology

Data availability statement: Data available on request. Additional data is provided in the supplementary information.

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This is an open access article distributed under the CC BY-NC 4.0 license (http://creativecommons.org/licenses/by-nc/4.0/).

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Panpho, P., Geraghty, B., Chim, Y.H. et al. Macro- and Micro-mechanical Properties of the Ovine Aorta: Correlation with Regional Variations in Collagen, Elastin and Glycosaminoglycan Levels. Artery Res 25, 27–36 (2019). https://doi.org/10.2991/artres.k.191114.003

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  • DOI: https://doi.org/10.2991/artres.k.191114.003

Keywords

Artery Research

ISSN: 1876-4401

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