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Maes L, Vervenne T, Hendrickx A, Estrada AC, Van Hoof L, Verbrugghe P, Rega F, Jones EAV, Humphrey JD, Famaey N. Cell signaling and tissue remodeling in the pulmonary autograft after the Ross procedure: A computational study. J Biomech 2024; 171:112180. [PMID: 38906711 DOI: 10.1016/j.jbiomech.2024.112180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/20/2024] [Accepted: 05/31/2024] [Indexed: 06/23/2024]
Abstract
In the Ross procedure, a patient's pulmonary valve is transplanted in the aortic position. Despite advantages of this surgery, reoperation is still needed in many cases due to excessive dilatation of the pulmonary autograft. To further understand the failure mechanisms, we propose a multiscale model predicting adaptive processes in the autograft at the cell and tissue scale. The cell-scale model consists of a network model, that includes important signaling pathways and relations between relevant transcription factors and their target genes. The resulting gene activity leads to changes in the mechanical properties of the tissue, modeled as a constrained mixture of collagen, elastin and smooth muscle. The multiscale model is calibrated with findings from experiments in which seven sheep underwent the Ross procedure. The model is then validated against a different set of sheep experiments, for which a qualitative agreement between model and experiment is found. Model outcomes at the cell scale, including the activity of genes and transcription factors, also match experimentally obtained transcriptomics data.
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Affiliation(s)
- Lauranne Maes
- BioMechanics, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium.
| | - Thibault Vervenne
- BioMechanics, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Amber Hendrickx
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Ana C Estrada
- Department of Biomedical Engineering, Yale University, New Haven CT, USA
| | - Lucas Van Hoof
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Peter Verbrugghe
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Filip Rega
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Elizabeth A V Jones
- Centre for Molecular and Vascular Biology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium; CARIM School for Cardiovascular Diseases, Department of Cardiology, Maastricht University, Maastricht, Netherlands
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven CT, USA
| | - Nele Famaey
- BioMechanics, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
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Vervenne T, Maes L, Van Hoof L, Rega F, Famaey N. Drivers of vascular growth and remodeling: A computational framework to promote benign adaptation in the Ross procedure. J Mech Behav Biomed Mater 2023; 148:106170. [PMID: 37852088 DOI: 10.1016/j.jmbbm.2023.106170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/04/2023] [Accepted: 10/09/2023] [Indexed: 10/20/2023]
Abstract
In the sixties, Dr Donald Ross designed a surgical solution for young patients with aortic valve disease by using the patients' own pulmonary valve. The Ross procedure is the only aortic valve replacement technique that can restore long-term survival and preserve quality of life. The main failure mode of the Ross procedure is wall dilatation, potentially leading to valve regurgitation and leakage. Dilatation occurs due to the inability of the pulmonary autograft to adapt to the sudden increase in loading when exposing to aortic pressures. Previous experimental data has shown that a permanent external support wrapped around the artery can prevent the acute dilatation of the arterial wall. However, the textile support leads to stress-shielding phenomena due to the loss of mechanical wall compliance. We present a pragmatic and modular computational framework of arterial growth and remodeling predicting the long-term outcomes of cardiovascular tissue adaptation, with and without textile wrapping. The model integrates mean, systolic and diastolic pressures and assumes the resulting wall stresses to drive the biological remodeling rules. Rather than a single mean pressure or stress deviation from the homeostatic state, we demonstrate that only pulsatile stresses can predict available experimental results. Therefore, we suggest that a biodegradable external support could induce benign remodeling in the Ross procedure. Indeed, a biodegradable textile wrapped around the autograft fulfills the trade-off between prevention of acute dilatation on the one hand and recovery of arterial wall compliance on the other hand. After further validation, the computational framework can set the basis for the development of an actual biodegradable external support for the Ross procedure with optimized polymer mechanical properties and degradation behavior.
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Affiliation(s)
- Thibault Vervenne
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300, Leuven, 3001, Belgium.
| | - Lauranne Maes
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300, Leuven, 3001, Belgium
| | - Lucas Van Hoof
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, UZ Herestraat 49, Leuven, 3000, Belgium
| | - Filip Rega
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, UZ Herestraat 49, Leuven, 3000, Belgium
| | - Nele Famaey
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300, Leuven, 3001, Belgium
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Maes L, Vervenne T, Van Hoof L, Jones EAV, Rega F, Famaey N. Computational modeling reveals inflammation-driven dilatation of the pulmonary autograft in aortic position. Biomech Model Mechanobiol 2023; 22:1555-1568. [PMID: 36764979 DOI: 10.1007/s10237-023-01694-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 01/17/2023] [Indexed: 02/12/2023]
Abstract
The pulmonary autograft in the Ross procedure, where the aortic valve is replaced by the patient's own pulmonary valve, is prone to failure due to dilatation. This is likely caused by tissue degradation and maladaptation, triggered by the higher experienced mechanical loads in aortic position. In order to further grasp the causes of dilatation, this study presents a model for tissue growth and remodeling of the pulmonary autograft, using the homogenized constrained mixture theory and equations for immuno- and mechano-mediated mass turnover. The model outcomes, compared to experimental data from an animal model of the pulmonary autograft in aortic position, show that inflammation likely plays an important role in the mass turnover of the tissue constituents and therefore in the autograft dilatation over time. We show a better match and prediction of long-term outcomes assuming immuno-mediated mass turnover, and show that there is no linear correlation between the stress-state of the material and mass production. Therefore, not only mechanobiological homeostatic adaption should be taken into account in the development of growth and remodeling models for arterial tissue in similar applications, but also inflammatory processes.
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Affiliation(s)
- Lauranne Maes
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300 box 2419, 3001, Leuven, Belgium.
| | - Thibault Vervenne
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300 box 2419, 3001, Leuven, Belgium
| | - Lucas Van Hoof
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, UZ Herestraat 49 box 276, 3000, Leuven, Belgium
| | - Elizabeth A V Jones
- Centre for Molecular and Vascular Biology, KU Leuven, UZ Herestraat 49 box 911, 3000, Leuven, Belgium
| | - Filip Rega
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, UZ Herestraat 49 box 276, 3000, Leuven, Belgium
| | - Nele Famaey
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300 box 2419, 3001, Leuven, Belgium
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Van Hoof L, Verbrugghe P, Jones EAV, Humphrey JD, Janssens S, Famaey N, Rega F. Understanding Pulmonary Autograft Remodeling After the Ross Procedure: Stick to the Facts. Front Cardiovasc Med 2022; 9:829120. [PMID: 35224059 PMCID: PMC8865563 DOI: 10.3389/fcvm.2022.829120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 01/17/2022] [Indexed: 12/12/2022] Open
Abstract
The Ross, or pulmonary autograft, procedure presents a fascinating mechanobiological scenario. Due to the common embryological origin of the aortic and pulmonary root, the conotruncus, several authors have hypothesized that a pulmonary autograft has the innate potential to remodel into an aortic phenotype once exposed to systemic conditions. Most of our understanding of pulmonary autograft mechanobiology stems from the remodeling observed in the arterial wall, rather than the valve, simply because there have been many opportunities to study the walls of dilated autografts explanted at reoperation. While previous histological studies provided important clues on autograft adaptation, a comprehensive understanding of its determinants and underlying mechanisms is needed so that the Ross procedure can become a widely accepted aortic valve substitute in select patients. It is clear that protecting the autograft during the early adaptation phase is crucial to avoid initiating a sequence of pathological remodeling. External support in the freestanding Ross procedure should aim to prevent dilatation while simultaneously promoting remodeling, rather than preventing dilatation at the cost of vascular atrophy. To define the optimal mechanical properties and geometry for external support, the ideal conditions for autograft remodeling and the timeline of mechanical adaptation must be determined. We aimed to rigorously review pulmonary autograft remodeling after the Ross procedure. Starting from the developmental, microstructural and biomechanical differences between the pulmonary artery and aorta, we review autograft mechanobiology in relation to distinct clinical failure mechanisms while aiming to identify unmet clinical needs, gaps in current knowledge and areas for further research. By correlating clinical and experimental observations of autograft remodeling with established principles in cardiovascular mechanobiology, we aim to present an up-to-date overview of all factors involved in extracellular matrix remodeling, their interactions and potential underlying molecular mechanisms.
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Affiliation(s)
- Lucas Van Hoof
- Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Peter Verbrugghe
- Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | | | - Jay D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
| | - Stefan Janssens
- Department of Cardiology, University Hospitals Leuven, Leuven, Belgium
| | - Nele Famaey
- Biomechanics Section, KU Leuven, Leuven, Belgium
| | - Filip Rega
- Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
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