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Turčanová M, Fischer J, Hermanová M, Bednařík Z, Skácel P, Burša J. Biaxial stretch can overcome discrepancy between global and local orientations of wavy collagen fibres. J Biomech 2023; 161:111868. [PMID: 37976938 DOI: 10.1016/j.jbiomech.2023.111868] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 09/20/2023] [Accepted: 11/09/2023] [Indexed: 11/19/2023]
Abstract
Most frequently used structure-based constitutive models of arterial wall apply assumptions on two symmetric helical (and dispersed) fibre families which, however, are not well supported with histological findings where two collagen fibre families are seldom found. Moreover, bimodal distributions of fibre directions may originate also from their waviness combined with ignoring differences between local and global fibre orientations. In contrast, if the model parameters are identified without histological information on collagen fibre directions, the resulting mean angles of both fibre families are close to ±45°, which contradicts nearly all histologic findings. The presented study exploited automated polarized light microscopy for detection of collagen fibre directions in porcine aorta under different biaxial extensions and approximated the resulting histograms with unimodal and bimodal von Mises distributions. Their comparison showed dominantly circumferential orientation of collagen fibres. Their concentration parameter for unimodal distributions increased with circumferential load, no matter if acting uniaxially or equibiaxially. For bimodal distributions, the angle between both dominant fibre directions (chosen as measure of fibre alignment) decreased similarly for both uniaxial and equibiaxial loads. These results indicate the existence of a single family of wavy circumferential collagen fibres in all layers of the aortic wall. Bimodal distributions of fibre directions presented sometimes in literature may come rather from waviness of circumferentially arranged fibres than from two symmetric families of helical fibres. To obtain a final evidence, the fibre orientation should be analysed together with their waviness.
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Affiliation(s)
- Michaela Turčanová
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno 616 69, Czech Republic.
| | - Jiří Fischer
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno 616 69, Czech Republic
| | - Markéta Hermanová
- 1st Department of Pathology, St. Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Pekařská 664/53, 656 91 Brno, Czech Republic
| | - Zdeněk Bednařík
- 1st Department of Pathology, St. Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Pekařská 664/53, 656 91 Brno, Czech Republic
| | - Pavel Skácel
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno 616 69, Czech Republic
| | - Jiří Burša
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno 616 69, Czech Republic
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Cheng H, Li G, Dai J, Zhang K, Xu T, Wei L, Zhang X, Ding D, Hou J, Li J, Zhuang J, Tan K, Guo R. A fluid-structure interaction model accounting arterial vessels as a key part of the blood-flow engine for the analysis of cardiovascular diseases. Front Bioeng Biotechnol 2022; 10:981187. [PMID: 36061431 PMCID: PMC9438578 DOI: 10.3389/fbioe.2022.981187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
According to the classical Windkessel model, the heart is the only power source for blood flow, while the arterial system is assumed to be an elastic chamber that acts as a channel and buffer for blood circulation. In this paper we show that in addition to the power provided by the heart for blood circulation, strain energy stored in deformed arterial vessels in vivo can be transformed into mechanical work to propel blood flow. A quantitative relationship between the strain energy increment and functional (systolic, diastolic, mean and pulse blood pressure) and structural (stiffness, diameter and wall thickness) parameters of the aorta is described. In addition, details of blood flow across the aorta remain unclear due to changes in functional and other physiological parameters. Based on the arterial strain energy and fluid-structure interaction theory, the relationship between physiological parameters and blood supply to organs was studied, and a corresponding mathematical model was developed. The findings provided a new understanding about blood-flow circulation, that is, cardiac output allows blood to enter the aorta at an initial rate, and then strain energy stored in the elastic arteries pushes blood toward distal organs and tissues. Organ blood supply is a key factor in cardio-cerebrovascular diseases (CCVD), which are caused by changes in blood supply in combination with multiple physiological parameters. Also, some physiological parameters are affected by changes in blood supply, and vice versa. The model can explain the pathophysiological mechanisms of chronic diseases such as CCVD and hypertension among others, and the results are in good agreement with epidemiological studies of CCVD.
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Affiliation(s)
- Heming Cheng
- Department of Mechanics, Kunming University of Science and Technology, Kunming, China
- *Correspondence: Heming Cheng, ; Ke Zhang,
| | - Gen Li
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, China
| | - Jifeng Dai
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, China
| | - Ke Zhang
- Department of Mechanics, Kunming University of Science and Technology, Kunming, China
- Department of Hydraulic Engineering, Kunming University of Science and Technology, Kunming, China
- *Correspondence: Heming Cheng, ; Ke Zhang,
| | - Tianrui Xu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Liuchuang Wei
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, China
| | - Xue Zhang
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, China
| | - Dongfang Ding
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, China
| | - Jie Hou
- Department of Mechanics, Kunming University of Science and Technology, Kunming, China
| | - Jianyun Li
- Department of Mechanics, Kunming University of Science and Technology, Kunming, China
| | - Jiangping Zhuang
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, China
| | - Kaijun Tan
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, China
| | - Ran Guo
- Department of Mechanics, Kunming University of Science and Technology, Kunming, China
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