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Robinson A, Nkansah A, Bhat S, Karnik S, Jones S, Fairley A, Leung J, Wancura M, Sacks MS, Dasi LP, Cosgriff-Hernandez E. Hydrogel-polyurethane fiber composites with enhanced microarchitectural control for heart valve replacement. J Biomed Mater Res A 2024; 112:586-599. [PMID: 38018452 DOI: 10.1002/jbm.a.37641] [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: 06/08/2023] [Revised: 09/22/2023] [Accepted: 10/24/2023] [Indexed: 11/30/2023]
Abstract
Polymeric heart valves offer the potential to overcome the limited durability of tissue based bioprosthetic valves and the need for anticoagulant therapy of mechanical valve replacement options. However, developing a single-phase material with requisite biological properties and target mechanical properties remains a challenge. In this study, a composite heart valve material was developed where an electrospun mesh provides tunable mechanical properties and a hydrogel coating confers an antifouling surface for thromboresistance. Key biological responses were evaluated in comparison to glutaraldehyde-fixed pericardium. Platelet and bacterial attachment were reduced by 38% and 98%, respectively, as compared to pericardium that demonstrated the antifouling nature of the hydrogel coating. There was also a notable reduction (59%) in the calcification of the composite material as compared to pericardium. A custom 3D-printed hydrogel coating setup was developed to make valve composites for device-level hemodynamic testing. Regurgitation fraction (9.6 ± 1.8%) and effective orifice area (1.52 ± 0.34 cm2 ) met ISO 5840-2:2021 requirements. Additionally, the mean pressure gradient was comparable to current clinical bioprosthetic heart valves demonstrating preliminary efficacy. Although the hemodynamic properties are promising, it is anticipated that the random microarchitecture will result in suboptimal strain fields and peak stresses that may accelerate leaflet fatigue and degeneration. Previous computational work has demonstrated that bioinspired fiber microarchitectures can improve strain homogeneity of valve materials toward improving durability. To this end, we developed advanced electrospinning methodologies to achieve polyurethane fiber microarchitectures that mimic or exceed the physiological ranges of alignment, tortuosity, and curvilinearity present in the native valve. Control of fiber alignment from a random fiber orientation at a normalized orientation index (NOI) 14.2 ± 6.9% to highly aligned fibers at a NOI of 85.1 ± 1.4%. was achieved through increasing mandrel rotational velocity. Fiber tortuosity and curvilinearity in the range of native valve features were introduced through a post-spinning annealing process and fiber collection on a conical mandrel geometry, respectively. Overall, these studies demonstrate the potential of hydrogel-polyurethane fiber composite as a heart valve material. Future studies will utilize the developed advanced electrospinning methodologies in combination with model-directed fabrication toward optimizing durability as a function of fiber microarchitecture.
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Affiliation(s)
- Andrew Robinson
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Abbey Nkansah
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Sanchita Bhat
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Shweta Karnik
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Sarah Jones
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Ashauntee Fairley
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Jonathan Leung
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Megan Wancura
- Department of Chemistry, The University of Texas at Austin, Austin, Texas, USA
| | - Michael S Sacks
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, Austin, Texas, USA
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Lakshmi Prasad Dasi
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
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2
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Schwarz EL, Pegolotti L, Pfaller MR, Marsden AL. Beyond CFD: Emerging methodologies for predictive simulation in cardiovascular health and disease. BIOPHYSICS REVIEWS 2023; 4:011301. [PMID: 36686891 PMCID: PMC9846834 DOI: 10.1063/5.0109400] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 12/12/2022] [Indexed: 01/15/2023]
Abstract
Physics-based computational models of the cardiovascular system are increasingly used to simulate hemodynamics, tissue mechanics, and physiology in evolving healthy and diseased states. While predictive models using computational fluid dynamics (CFD) originated primarily for use in surgical planning, their application now extends well beyond this purpose. In this review, we describe an increasingly wide range of modeling applications aimed at uncovering fundamental mechanisms of disease progression and development, performing model-guided design, and generating testable hypotheses to drive targeted experiments. Increasingly, models are incorporating multiple physical processes spanning a wide range of time and length scales in the heart and vasculature. With these expanded capabilities, clinical adoption of patient-specific modeling in congenital and acquired cardiovascular disease is also increasing, impacting clinical care and treatment decisions in complex congenital heart disease, coronary artery disease, vascular surgery, pulmonary artery disease, and medical device design. In support of these efforts, we discuss recent advances in modeling methodology, which are most impactful when driven by clinical needs. We describe pivotal recent developments in image processing, fluid-structure interaction, modeling under uncertainty, and reduced order modeling to enable simulations in clinically relevant timeframes. In all these areas, we argue that traditional CFD alone is insufficient to tackle increasingly complex clinical and biological problems across scales and systems. Rather, CFD should be coupled with appropriate multiscale biological, physical, and physiological models needed to produce comprehensive, impactful models of mechanobiological systems and complex clinical scenarios. With this perspective, we finally outline open problems and future challenges in the field.
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Affiliation(s)
- Erica L. Schwarz
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Luca Pegolotti
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Martin R. Pfaller
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Alison L. Marsden
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
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3
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Salinas SD, Farra YM, Amini Khoiy K, Houston J, Lee CH, Bellini C, Amini R. The role of elastin on the mechanical properties of the anterior leaflet in porcine tricuspid valves. PLoS One 2022; 17:e0267131. [PMID: 35560311 PMCID: PMC9106221 DOI: 10.1371/journal.pone.0267131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 04/02/2022] [Indexed: 11/19/2022] Open
Abstract
Elastin is present in the extracellular matrix (ECM) of connective tissues, and its mechanical properties are well documented. In Marfan syndrome, however, the inability to properly code for the protein fibrillin-1 prematurely leads to the degradation and loss of elastin fiber integrity in the ECM. In this study, the role of elastin in the ECM of the anterior leaflet of the tricuspid valve was investigated by examining the biomechanical behavior of porcine leaflets before and after the application of the enzyme elastase. Five loading protocols were applied to the leaflet specimens in two groups (elastase-treated and control samples). The mechanical response following elastase application yielded a significantly stiffer material in both the radial and circumferential directions. At a physiological level of stress (85 kPa), the elastase group had an average strain of 26.21% and 6.32% in the radial and circumferential directions, respectively, at baseline prior to elastase application. Following elastase treatment, the average strain was 5.28% and 0.97% in the radial and circumferential directions, respectively. No statistically significant change was found in the control group following sham treatment with phosphate-buffered saline (PBS). Two-photon microscopy images confirmed that after the removal of elastin, the collagen fibers displayed a loss of undulation. With a significant reduction in radial compliance, the ability to withstand physiological loads may be compromised. As such, an extracellular matrix that is structurally deficient in elastin may hinder normal tricuspid valve function.
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Affiliation(s)
- Samuel D. Salinas
- Department of Bioengineering, Northeastern University, Boston, MA, United States of America
- Department of Biomedical Engineering, The University of Akron, Akron, OH, United States of America
| | - Yasmeen M. Farra
- Department of Bioengineering, Northeastern University, Boston, MA, United States of America
| | - Keyvan Amini Khoiy
- Department of Biomedical Engineering, The University of Akron, Akron, OH, United States of America
| | - James Houston
- Department of Psychology, Middle Tennessee State University, Murfreesboro, TN, United States of America
| | - Chung-Hao Lee
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK, United States of America
| | - Chiara Bellini
- Department of Biomedical Engineering, The University of Akron, Akron, OH, United States of America
| | - Rouzbeh Amini
- Department of Bioengineering, Northeastern University, Boston, MA, United States of America
- Department of Biomedical Engineering, The University of Akron, Akron, OH, United States of America
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, United States of America
- * E-mail:
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4
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Anisotropic elastic behavior of a hydrogel-coated electrospun polyurethane: Suitability for heart valve leaflets. J Mech Behav Biomed Mater 2022; 125:104877. [PMID: 34695661 PMCID: PMC8818123 DOI: 10.1016/j.jmbbm.2021.104877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/20/2021] [Accepted: 09/30/2021] [Indexed: 01/03/2023]
Abstract
Although xenograft biomaterials have been used for decades in replacement heart valves, they continue to face multiple limitations, including limited durability, mineralization, and restricted design space due to their biological origins. These issues necessitate the need for novel replacement heart valve biomaterials that are durable, non-thrombogenic, and compatible with transcatheter aortic valve replacement devices. In this study, we explored the suitability of an electrospun poly(carbonate urethane) (ES-PCU) mesh coated with a poly(ethylene glycol) diacrylate (PEGDA) hydrogel as a synthetic biomaterial for replacement heart valve leaflets. In this material design, the mesh provides the mechanical support, while the hydrogel provides the required surface hemocompatibility. We conducted a comprehensive study to characterize the structural and mechanical properties of the uncoated mesh as well as the hydrogel-coated mesh (composite biomaterial) over the estimated operational range. We found that the composite biomaterial was functionally robust with reproducible stress-strain behavior within and beyond the functional ranges for replacement heart valves, and was able to withstand the rigors of mechanical evaluation without any observable damage. In addition, the composite biomaterial displayed a wide range of mechanical anisotropic responses, which were governed by fiber orientation of the mesh, which in turn, was controlled with the fabrication process. Finally, we developed a novel constitutive modeling approach to predict the mechanical behavior of the composite biomaterial under in-plane extension and shear deformation modes. This model identified the existence of fiber-fiber mechanical interactions in the mesh that have not previously been reported. Interestingly, there was no evidence of fiber-hydrogel mechanical interactions. This important finding suggests that the hydrogel coating can be optimized for hemocompatibility independent of the structural mechanical responses required by the leaflet. This initial study indicated that the composite biomaterial has mechanical properties well-suited for replacement heart valve applications and that the electrospun mesh microarchitecture and hydrogel biological properties can be optimized independently. It also reveals that the structural mechanisms contributing to the mechanical response are more complicated than what was previously established and paves the pathway for more detailed future studies.
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What Can We Learn from the Past by Means of Very Long-Term Follow-Up after Aortic Valve Replacement? J Clin Med 2021; 10:jcm10173925. [PMID: 34501375 PMCID: PMC8432120 DOI: 10.3390/jcm10173925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/23/2021] [Accepted: 08/29/2021] [Indexed: 11/18/2022] Open
Abstract
Background: Studies on very long-term outcomes after aortic valve replacement are sparse. Methods: In this retrospective cohort study, long-term outcomes during 25.1 ± 2.8 years of follow-up were determined in 673 patients who underwent aortic valve replacement with or without concomitant coronary artery bypass surgery for severe aortic stenosis and/or regurgitation. Independent predictors of decreased long-term survival were determined. Cumulative incidence rates of major adverse events in patients with a mechanical versus those with a biologic prosthesis were assessed, as well as of major bleeding events in patients with a mechanical prosthesis under the age of 60 versus those above the age of 60. Results: Impaired left ventricular function, severe prosthesis–patient mismatch, and increased aortic cross-clamp time were independent predictors of decreased long-term survival. Left ventricular hypertrophy, a mechanical or biologic prosthesis, increased cardiopulmonary bypass time, new-onset postoperative atrial fibrillation, and the presence of symptoms did not independently predict decreased long-term survival. The risk of major bleeding events was higher in patients with a mechanical in comparison with those with a biologic prosthesis. Younger age (under 60 years) did not protect patients with a mechanical prosthesis against major bleeding events. Conclusions: Very long-term outcome data are invaluable for careful decision-making on aortic valve replacement.
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Goodwin RL, Kheradvar A, Norris RA, Price RL, Potts JD. Collagen Fibrillogenesis in the Mitral Valve: It's a Matter of Compliance. J Cardiovasc Dev Dis 2021; 8:jcdd8080098. [PMID: 34436240 PMCID: PMC8397013 DOI: 10.3390/jcdd8080098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 07/30/2021] [Accepted: 08/16/2021] [Indexed: 11/16/2022] Open
Abstract
Collagen fibers are essential structural components of mitral valve leaflets, their tension apparatus (chordae tendineae), and the associated papillary muscles. Excess or lack of collagen fibers in the extracellular matrix (ECM) in any of these structures can adversely affect mitral valve function. The organization of collagen fibers provides a sophisticated framework that allows for unidirectional blood flow during the precise opening and closing of this vital heart valve. Although numerous ECM molecules are essential for the differentiation, growth, and homeostasis of the mitral valve (e.g., elastic fibers, glycoproteins, and glycans), collagen fibers are key to mitral valve integrity. Besides the inert structural components of the tissues, collagen fibers are dynamic structures that drive outside-to-inside cell signaling, which informs valvular interstitial cells (VICs) present within the tissue environment. Diversity of collagen family members and the closely related collagen-like triple helix-containing proteins found in the mitral valve, will be discussed in addition to how defects in these proteins may lead to valve disease.
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Affiliation(s)
- Richard L. Goodwin
- Department of Biomedical Sciences, School of Medicine Greenville, University of South Carolina, Greenville, SC 29605, USA
- Correspondence:
| | - Arash Kheradvar
- Department of Biomedical Engineering, The Henry Samueli School of Engineering, University of California, Irvine, CA 92697, USA;
| | - Russell A. Norris
- Department of Regenerative Medicine, School of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA;
| | - Robert L. Price
- Department of Cell Biology and Anatomy, School of Medicine, University of South Carolina, Greenville, SC 29605, USA; (R.L.P.); (J.D.P.)
| | - Jay D. Potts
- Department of Cell Biology and Anatomy, School of Medicine, University of South Carolina, Greenville, SC 29605, USA; (R.L.P.); (J.D.P.)
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7
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Movileanu I, Harpa M, Al Hussein H, Harceaga L, Chertes A, Al Hussein H, Lutter G, Puehler T, Preda T, Sircuta C, Cotoi O, Nistor D, Man A, Cordos B, Deac R, Suciu H, Brinzaniuc K, Casco M, Sierad L, Bruce M, Simionescu D, Simionescu A. Preclinical Testing of Living Tissue-Engineered Heart Valves for Pediatric Patients, Challenges and Opportunities. Front Cardiovasc Med 2021; 8:707892. [PMID: 34490371 PMCID: PMC8416773 DOI: 10.3389/fcvm.2021.707892] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 07/05/2021] [Indexed: 12/02/2022] Open
Abstract
Introduction: Pediatric patients with cardiac congenital diseases require heart valve implants that can grow with their natural somatic increase in size. Current artificial valves perform poorly in children and cannot grow; thus, living-tissue-engineered valves capable of sustaining matrix homeostasis could overcome the current drawbacks of artificial prostheses and minimize the need for repeat surgeries. Materials and Methods: To prepare living-tissue-engineered valves, we produced completely acellular ovine pulmonary valves by perfusion. We then collected autologous adipose tissue, isolated stem cells, and differentiated them into fibroblasts and separately into endothelial cells. We seeded the fibroblasts in the cusp interstitium and onto the root adventitia and the endothelial cells inside the lumen, conditioned the living valves in dedicated pulmonary heart valve bioreactors, and pursued orthotopic implantation of autologous cell-seeded valves with 6 months follow-up. Unseeded valves served as controls. Results: Perfusion decellularization yielded acellular pulmonary valves that were stable, no degradable in vivo, cell friendly and biocompatible, had excellent hemodynamics, were not immunogenic or inflammatory, non thrombogenic, did not calcify in juvenile sheep, and served as substrates for cell repopulation. Autologous adipose-derived stem cells were easy to isolate and differentiate into fibroblasts and endothelial-like cells. Cell-seeded valves exhibited preserved viability after progressive bioreactor conditioning and functioned well in vivo for 6 months. At explantation, the implants and anastomoses were intact, and the valve root was well integrated into host tissues; valve leaflets were unchanged in size, non fibrotic, supple, and functional. Numerous cells positive for a-smooth muscle cell actin were found mostly in the sinus, base, and the fibrosa of the leaflets, and most surfaces were covered by endothelial cells, indicating a strong potential for repopulation of the scaffold. Conclusions: Tissue-engineered living valves can be generated in vitro using the approach described here. The technology is not trivial and can provide numerous challenges and opportunities, which are discussed in detail in this paper. Overall, we concluded that cell seeding did not negatively affect tissue-engineered heart valve (TEHV) performance as they exhibited as good hemodynamic performance as acellular valves in this model. Further understanding of cell fate after implantation and the timeline of repopulation of acellular scaffolds will help us evaluate the translational potential of this technology.
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Affiliation(s)
- Ionela Movileanu
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
- Institute of Cardiovascular Diseases and Transplant, Târgu Mureş, Romania
| | - Marius Harpa
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
- Institute of Cardiovascular Diseases and Transplant, Târgu Mureş, Romania
| | - Hussam Al Hussein
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
- Institute of Cardiovascular Diseases and Transplant, Târgu Mureş, Romania
| | - Lucian Harceaga
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
| | - Alexandru Chertes
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
| | - Hamida Al Hussein
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
| | - Georg Lutter
- Department for Experimental Cardiac Surgery and Heart Valve Replacement, School of Medicine, University of Kiel, Kiel, Germany
| | - Thomas Puehler
- Department for Experimental Cardiac Surgery and Heart Valve Replacement, School of Medicine, University of Kiel, Kiel, Germany
| | - Terezia Preda
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
| | - Carmen Sircuta
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
| | - Ovidiu Cotoi
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
| | - Dan Nistor
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
- Institute of Cardiovascular Diseases and Transplant, Târgu Mureş, Romania
| | - Adrian Man
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
| | - Bogdan Cordos
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
| | - Radu Deac
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
| | - Horatiu Suciu
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
- Institute of Cardiovascular Diseases and Transplant, Târgu Mureş, Romania
| | - Klara Brinzaniuc
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
- Institute of Cardiovascular Diseases and Transplant, Târgu Mureş, Romania
| | - Megan Casco
- Biocompatibility and Tissue Regeneration Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, United States
| | | | - Margarita Bruce
- Biocompatibility and Tissue Regeneration Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, United States
| | - Dan Simionescu
- Regenerative Medicine Laboratory, University of Medicine, Pharmacy, Science and Technology “George Emil Palade”, Târgu Mureş, Romania
- Biocompatibility and Tissue Regeneration Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, United States
| | - Agneta Simionescu
- Tissue Engineering Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, United States
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8
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Bui HT, Khair N, Yeats B, Gooden S, James SP, Dasi LP. Transcatheter Heart Valves: A Biomaterials Perspective. Adv Healthc Mater 2021; 10:e2100115. [PMID: 34038627 DOI: 10.1002/adhm.202100115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/23/2021] [Indexed: 11/11/2022]
Abstract
Heart valve disease is prevalent throughout the world, and the number of heart valve replacements is expected to increase rapidly in the coming years. Transcatheter heart valve replacement (THVR) provides a safe and minimally invasive means for heart valve replacement in high-risk patients. The latest clinical data demonstrates that THVR is a practical solution for low-risk patients. Despite these promising results, there is no long-term (>20 years) durability data on transcatheter heart valves (THVs), raising concerns about material degeneration and long-term performance. This review presents a detailed account of the materials development for THVRs. It provides a brief overview of THVR, the native valve properties, the criteria for an ideal THV, and how these devices are tested. A comprehensive review of materials and their applications in THVR, including how these materials are fabricated, prepared, and assembled into THVs is presented, followed by a discussion of current and future THVR biomaterial trends. The field of THVR is proliferating, and this review serves as a guide for understanding the development of THVs from a materials science and engineering perspective.
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Affiliation(s)
- Hieu T. Bui
- Department of Biomedical Engineering Georgia Institute of Technology 387 Technology Cir NW Atlanta GA 30313 USA
| | - Nipa Khair
- School of Advanced Materials Discovery Colorado State University 700 Meridian Ave Fort Collins CO 80523 USA
| | - Breandan Yeats
- Department of Biomedical Engineering Georgia Institute of Technology 387 Technology Cir NW Atlanta GA 30313 USA
| | - Shelley Gooden
- Department of Biomedical Engineering Georgia Institute of Technology 387 Technology Cir NW Atlanta GA 30313 USA
| | - Susan P. James
- School of Advanced Materials Discovery Colorado State University 700 Meridian Ave Fort Collins CO 80523 USA
| | - Lakshmi Prasad Dasi
- Department of Biomedical Engineering Georgia Institute of Technology 387 Technology Cir NW Atlanta GA 30313 USA
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9
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Gähwiler EKN, Motta SE, Martin M, Nugraha B, Hoerstrup SP, Emmert MY. Human iPSCs and Genome Editing Technologies for Precision Cardiovascular Tissue Engineering. Front Cell Dev Biol 2021; 9:639699. [PMID: 34262897 PMCID: PMC8273765 DOI: 10.3389/fcell.2021.639699] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 03/31/2021] [Indexed: 12/12/2022] Open
Abstract
Induced pluripotent stem cells (iPSCs) originate from the reprogramming of adult somatic cells using four Yamanaka transcription factors. Since their discovery, the stem cell (SC) field achieved significant milestones and opened several gateways in the area of disease modeling, drug discovery, and regenerative medicine. In parallel, the emergence of clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (CRISPR-Cas9) revolutionized the field of genome engineering, allowing the generation of genetically modified cell lines and achieving a precise genome recombination or random insertions/deletions, usefully translated for wider applications. Cardiovascular diseases represent a constantly increasing societal concern, with limited understanding of the underlying cellular and molecular mechanisms. The ability of iPSCs to differentiate into multiple cell types combined with CRISPR-Cas9 technology could enable the systematic investigation of pathophysiological mechanisms or drug screening for potential therapeutics. Furthermore, these technologies can provide a cellular platform for cardiovascular tissue engineering (TE) approaches by modulating the expression or inhibition of targeted proteins, thereby creating the possibility to engineer new cell lines and/or fine-tune biomimetic scaffolds. This review will focus on the application of iPSCs, CRISPR-Cas9, and a combination thereof to the field of cardiovascular TE. In particular, the clinical translatability of such technologies will be discussed ranging from disease modeling to drug screening and TE applications.
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Affiliation(s)
- Eric K. N. Gähwiler
- Institute for Regenerative Medicine (IREM), University of Zurich, Zurich, Switzerland
| | - Sarah E. Motta
- Institute for Regenerative Medicine (IREM), University of Zurich, Zurich, Switzerland
- Wyss Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Marcy Martin
- Division of Pediatric Cardiology, Department of Pediatrics, Stanford School of Medicine, Stanford, CA, United States
- Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford School of Medicine, Stanford, CA, United States
- Stanford Cardiovascular Institute, Stanford School of Medicine, Stanford, CA, United States
| | - Bramasta Nugraha
- Molecular Parasitology Lab, Institute of Parasitology, University of Zurich, Zurich, Switzerland
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism, R&D BioPharmaceuticals, AstraZeneca, Gothenburg, Sweden
| | - Simon P. Hoerstrup
- Institute for Regenerative Medicine (IREM), University of Zurich, Zurich, Switzerland
- Wyss Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Maximilian Y. Emmert
- Institute for Regenerative Medicine (IREM), University of Zurich, Zurich, Switzerland
- Wyss Zurich, University and ETH Zurich, Zurich, Switzerland
- Department of Cardiovascular Surgery, Charité Universitätsmedizin Berlin, Berlin, Germany
- Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, Berlin, Germany
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10
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Guo R, Zhou Y, Liu S, Li C, Lu C, Yang G, Nie J, Wang F, Dong NG, Shi J. Anticalcification Potential of POSS-PEG Hybrid Hydrogel as a Scaffold Material for the Development of Synthetic Heart Valve Leaflets. ACS APPLIED BIO MATERIALS 2021; 4:2534-2543. [PMID: 35014371 DOI: 10.1021/acsabm.0c01544] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Calcification of bioprosthetics is a primary challenge in the field of artificial heart valves and a main reason for biological heart valve prostheses failure. Recent advances in nanomaterial science have promoted the development of polymers with advantageous properties that are likely suitable for artificial heart valves. In this work, we developed a nanocomposite polymeric biomaterial POSS-PEG (polyhedral oligomeric silsesquioxane-polyethylene glycol) hybrid hydrogel, which not only has improved mechanical and surface properties but also excellent biocompatibility. The results of atomic force microscopy and in vivo animal experiments indicated that the content of POSS in the PEG matrix plays an important role on the surface and contributes to its biological properties, compared to the decellularized porcine aortic valve scaffold. Additionally, this modification leads to enhanced protection of the hydrogel from thrombosis. Furthermore, the introduction of POSS nanoparticles also gives the hydrogel a better calcification resistance efficacy, which was confirmed through in vitro tests and animal experiments. These findings indicate that POSS-PEG hybrid hydrogel is a potential material for functional heart valve prosthetics, and the use of POSS nanocomposites in artificial valves may offer potential long-term performance and durability advantages.
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Affiliation(s)
- Renqi Guo
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
| | - Ying Zhou
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Siju Liu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
| | - Chuang Li
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
| | - Cuifen Lu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
| | - Guichun Yang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
| | - Junqi Nie
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
| | - Feiyi Wang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
| | - Nian-Guo Dong
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jiawei Shi
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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11
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Roseen MA, Lee R, Post AD, Wancura M, Connell JP, Cosgriff-Hernandez E, Grande-Allen KJ. Poly(ethylene glycol)-Based Coatings for Bioprosthetic Valve Tissues: Toward Restoration of Physiological Behavior. ACS APPLIED BIO MATERIALS 2020; 3:8352-8360. [PMID: 35019607 DOI: 10.1021/acsabm.0c00550] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bioprosthetic valves (BPVs) have a limited lifespan in the body necessitating repeated surgeries to replace the failed implant. Early failure of these implants has been linked to various surface properties of the valve. Surface properties of BPVs are significantly different from physiological valves because of the fixation process used when processing the xenograft tissue. To improve the longevity of BPVs, efforts need to be taken to improve the surface properties and shield the implant from the bodily interactions that degrade it. Toward this goal, we evaluated the use of hydrogel coatings to attach to the BPV tissue and impart surface properties that are close to physiological. Hydrogels are well characterized for their biocompatibility and highly tunable surface characteristics. Using a previously published coating method, we deposited hydrogel coatings of poly(ethylene glycol)diacrylate (PEGDA) and poly(ethylene glycol)diacrylamide (PEGDAA) atop BPV samples. Coated samples were evaluated against the physiological tissue and uncoated glutaraldehyde-fixed tissue for deposition of hydrogel, surface adherence, mechanical properties, and fixation properties. Results showed both PEGDA- and PEGDAA-deposited coatings were nearly continuous across the valve leaflet surface. Further, the PEGDA- and PEGDAA-coated samples showed restoration of physiological levels of protein adhesion and mechanical stiffness. Interestingly, the coating process rather than the coating itself altered the material behavior yet did not alter the cross-linking from fixation. These results show that the PEG-based coatings for BPVs can successfully alter surface properties of BPVs and help promote physiological characteristics without interfering with the necessary fixation.
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Affiliation(s)
- Madeleine A Roseen
- Department of Bioengineering, Rice University, Houston 77005, Texas, United States
| | - Romi Lee
- Department of Bioengineering, Rice University, Houston 77005, Texas, United States
| | - Allison D Post
- Department of Biomedical Engineering, University of Texas at Austin, Austin 78712, Texas, United States
| | - Megan Wancura
- Department of Chemistry, University of Texas at Austin, Austin 78712, Texas, United States
| | - Jennifer P Connell
- Department of Bioengineering, Rice University, Houston 77005, Texas, United States
| | | | - K Jane Grande-Allen
- Department of Bioengineering, Rice University, Houston 77005, Texas, United States
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12
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Lan X, Zhao Q, Zhang J, Lei Y, Wang Y. A combination of hydrogen bonding and chemical covalent crosslinking to fabricate a novel swim-bladder-derived dry heart valve material yields advantageous mechanical and biological properties. Biomed Mater 2020; 16:015014. [DOI: 10.1088/1748-605x/abb616] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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13
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Chandika P, Heo SY, Kim TH, Oh GW, Kim GH, Kim MS, Jung WK. Recent advances in biological macromolecule based tissue-engineered composite scaffolds for cardiac tissue regeneration applications. Int J Biol Macromol 2020; 164:2329-2357. [DOI: 10.1016/j.ijbiomac.2020.08.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/01/2020] [Accepted: 08/06/2020] [Indexed: 12/11/2022]
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14
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In Vitro Durability and Stability Testing of a Novel Polymeric Transcatheter Aortic Valve. ASAIO J 2020; 66:190-198. [PMID: 30845067 DOI: 10.1097/mat.0000000000000980] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Transcatheter aortic valve replacement (TAVR) has emerged as an effective therapy for the unmet clinical need of inoperable patients with severe aortic stenosis (AS). Current clinically used tissue TAVR valves suffer from limited durability that hampers TAVR's rapid expansion to younger, lower risk patients. Polymeric TAVR valves optimized for hemodynamic performance, hemocompatibility, extended durability, and resistance to calcific degeneration offer a viable solution to this challenge. We present extensive in vitro durability and stability testing of a novel polymeric TAVR valve (PolyNova valve) using 1) accelerated wear testing (AWT, ISO 5840); 2) calcification susceptibility (in the AWT)-compared with clinically used tissue valves; and 3) extended crimping stability (valves crimped to 16 Fr for 8 days). Hydrodynamic testing was performed every 50M cycles. The valves were also evaluated visually for structural integrity and by scanning electron microscopy for evaluation of surface damage in the micro-scale. Calcium and phosphorus deposition was evaluated using micro-computed tomography (μCT) and inductive coupled plasma spectroscopy. The valves passed 400M cycles in the AWT without failure. The effective orifice area kept stable at 1.8 cm with a desired gradual decrease in transvalvular pressure gradient and regurgitation (10.4 mm Hg and 6.9%, respectively). Calcium and phosphorus deposition was significantly lower in the polymeric valve: down by a factor of 85 and 16, respectively-as compared to a tissue valve. Following the extended crimping testing, no tears nor surface damage were evident. The results of this study demonstrate the potential of a polymeric TAVR valve to be a viable alternative to tissue-based TAVR valves.
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15
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Amadeo F, Barbuto M, Bernava G, Savini N, Brioschi M, Rizzi S, Banfi C, Polvani G, Pesce M. Culture Into Perfusion-Assisted Bioreactor Promotes Valve-Like Tissue Maturation of Recellularized Pericardial Membrane. Front Cardiovasc Med 2020; 7:80. [PMID: 32478099 PMCID: PMC7235194 DOI: 10.3389/fcvm.2020.00080] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/15/2020] [Indexed: 11/13/2022] Open
Abstract
Derivation of tissue-engineered valve replacements is a strategy to overcome the limitations of the current valve prostheses, mechanical, or biological. In an effort to set living pericardial material for aortic valve reconstruction, we have previously assessed the efficiency of a recellularization strategy based on a perfusion system enabling mass transport and homogenous distribution of aortic valve-derived "interstitial" cells inside decellularized pericardial material. In the present report, we show that alternate perfusion promoted a rapid growth of valve cells inside the pericardial material and the activity of a proliferation-supporting pathway, likely controlled by the YAP transcription factor, a crucial component of the Hippo-dependent signaling cascade, especially between 3 and 14 days of culture. Quantitative mass spectrometry analysis of protein content in the tissue constructs showed deposition of valve proteins in the decellularized pericardium with a high variability at day 14 and a reproducible tissue maturation at 21 days. These results represent a step forward in the definition of strategies to produce a fully engineered tissue for replacing the calcified leaflets of failing aortic valves.
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Affiliation(s)
- Francesco Amadeo
- Unità di Ingegneria Tissutale Cardiovascolare, Centro Cardiologico Monzino, IRCCS, Milan, Italy
| | - Marianna Barbuto
- Unità di Ingegneria Tissutale Cardiovascolare, Centro Cardiologico Monzino, IRCCS, Milan, Italy
| | - Giacomo Bernava
- Unità di Ingegneria Tissutale Cardiovascolare, Centro Cardiologico Monzino, IRCCS, Milan, Italy
| | - Nicla Savini
- Unità di Ingegneria Tissutale Cardiovascolare, Centro Cardiologico Monzino, IRCCS, Milan, Italy
| | - Maura Brioschi
- Unità di Proteomica, Centro Cardiologico Monzino, IRCCS, Milan, Italy
| | - Stefano Rizzi
- Unità di Ingegneria Tissutale Cardiovascolare, Centro Cardiologico Monzino, IRCCS, Milan, Italy
| | - Cristina Banfi
- Unità di Proteomica, Centro Cardiologico Monzino, IRCCS, Milan, Italy
| | - Gianluca Polvani
- Dipartimento di Scienze Cliniche e di Comunità, Università degli studi di Milano, Milan, Italy
| | - Maurizio Pesce
- Unità di Ingegneria Tissutale Cardiovascolare, Centro Cardiologico Monzino, IRCCS, Milan, Italy
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16
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Abstract
Heart valve diseases are common disorders with five million annual diagnoses being made in the United States alone. All heart valve disorders alter cardiac hemodynamic performance; therefore, treatments aim to restore normal flow. This paper reviews the state-of-the-art clinical and engineering advancements in heart valve treatments with a focus on hemodynamics. We review engineering studies and clinical literature on the experience with devices for aortic valve treatment, as well as the latest advancements in mitral valve treatments and the pulmonic and tricuspid valves on the right side of the heart. Upcoming innovations will potentially revolutionize treatment of heart valve disorders. These advancements, and more gradual enhancements in the procedural techniques and imaging modalities, could improve the quality of life of patients suffering from valvular disease who currently cannot be treated.
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Affiliation(s)
- Gil Marom
- School of Mechanical Engineering, Tel Aviv University, Tel Aviv Israel
- To whom correspondence should be addressed. E-mail:
| | - Shmuel Einav
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
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17
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In Vivo Stability of Polyurethane-Based Electrospun Vascular Grafts in Terms of Chemistry and Mechanics. Polymers (Basel) 2020; 12:polym12040845. [PMID: 32272564 PMCID: PMC7240619 DOI: 10.3390/polym12040845] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 12/31/2022] Open
Abstract
The biostability of the polyurethanes Tecoflex EG-80A and Pellethane 2363-80A, used as basic polymers of the vascular grafts (VGs) produced by electrospinning, as well as the tensile strength of Tecoflex VGs, are studied. Solutions of Tecoflex or Pellethane with gelatin and bivalirudin in 1,1,1,3,3,3-hexafluoroisopropanol are used for VG production. After 1, 12, and 24 weeks of VG implantation in the infrarenal position of the abdominal aorta of Wistar rats, VGs are explanted, fixed in formalin, freed from outer tissues, dialyzed, and dried. The polyurethanes are extracted from VGs by dispersion/extraction in tetrahydrofuran (THF) and freed from the excess of THF-insoluble biopolymers. The stability of polyurethanes is assessed by IR spectroscopy and gel permeation chromatography. Pellethane has emerged to be stable at all experimental points. Tecoflex loses approximately 10% of its molecular weight (both Mn and Mw) after 3 months and restored its initial value within 6 months of its functioning as a graft. Mechanical testing demonstrates a 30% reduction in the tensile strength after 3 months in VG and a 10% increase after 6 months. The stability and mechanical properties of polyurethane-based VGs demonstrate their utility for the reconstitution of damaged arteries.
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18
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Roseen MA, Fahrenholtz MM, Connell JP, Grande-Allen KJ. Interfacial Coating Method for Amine-Rich Surfaces using Poly(ethylene glycol) Diacrylate Applied to Bioprosthetic Valve Tissue Models. ACS APPLIED BIO MATERIALS 2020; 3:1321-1330. [PMID: 35021626 DOI: 10.1021/acsabm.9b00911] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Bioprosthetic heart valve implants are beset by calcification and failure due to the interactions between the body and the transplant. Hydrogels can be used as biological blank slates that may help to shield implants from these interactions; however, traditional light-based hydrogel polymerization is impeded by tissue opacity and topography. Therefore, new methods must be created to bind hydrogel to implant tissues. To address these complications, a two-step surface-coating method for bioprosthetic valves was developed. A previously developed bioprosthetic valve model (VM) was used to investigate and optimize the coating method. Generally, this coating is achieved by first reacting surface amine groups with an NHS-PEG-acrylate while also allowing glucose to absorb into the bulk. Then, glucose oxidase, poly(ethylene glycol) diacrylate (PEGDA), and iron ions are added to the system to initiate free-radical polymerization that bonds the PEGDA hydrogel to the acrylates sites on the surface. Results showed a thin (∼8 μm), continuous coating on VM samples that is capable of repelling protein adhesion (2% surface fouling versus 20% on uncoated samples) and does not significantly affect the surface mechanical properties. Based on this success, the coating method was translated to glutaraldehyde-fixed valve tissue samples. Results showed noncontinuous but evident coating on the surface, which was further improved by adjusting the coating solution. These results demonstrate the feasibility of the proposed two-step surface coating method for modifying the surface of bioprosthetic valve replacements.
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Affiliation(s)
- Madeleine A Roseen
- Rice University, Department of Bioengineering, 6100 Main St, Houston, Texas 77035, United States
| | - Monica M Fahrenholtz
- Rice University, Department of Bioengineering, 6100 Main St, Houston, Texas 77035, United States.,Texas Children's Hospital, Department of Surgery, 6621 Fannin St, Houston, Texas 77030, United States
| | - Jennifer P Connell
- Rice University, Department of Bioengineering, 6100 Main St, Houston, Texas 77035, United States
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19
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Hong JK, Gao L, Singh J, Goh T, Ruhoff AM, Neto C, Waterhouse A. Evaluating medical device and material thrombosis under flow: current and emerging technologies. Biomater Sci 2020; 8:5824-5845. [DOI: 10.1039/d0bm01284j] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review highlights the importance of flow in medical device thrombosis and explores current and emerging technologies to evaluate dynamic biomaterial Thrombosis in vitro.
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Affiliation(s)
- Jun Ki Hong
- School of Chemistry
- The University of Sydney
- Australia
- School of Medical Sciences
- Faculty of Medicine and Health
| | - Lingzi Gao
- Heart Research Institute
- Newtown
- Australia
- The University of Sydney Nano Institute
- The University of Sydney
| | - Jasneil Singh
- Heart Research Institute
- Newtown
- Australia
- The Charles Perkins Centre
- The University of Sydney
| | - Tiffany Goh
- Heart Research Institute
- Newtown
- Australia
- The Charles Perkins Centre
- The University of Sydney
| | - Alexander M. Ruhoff
- Heart Research Institute
- Newtown
- Australia
- The Charles Perkins Centre
- The University of Sydney
| | - Chiara Neto
- School of Chemistry
- The University of Sydney
- Australia
- The University of Sydney Nano Institute
- The University of Sydney
| | - Anna Waterhouse
- School of Medical Sciences
- Faculty of Medicine and Health
- The University of Sydney
- Australia
- Heart Research Institute
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20
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Animal Surgery and Care of Animals. Biomater Sci 2020. [DOI: 10.1016/b978-0-12-816137-1.00060-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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21
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Zhang BL, Bianco RW, Schoen FJ. Preclinical Assessment of Cardiac Valve Substitutes: Current Status and Considerations for Engineered Tissue Heart Valves. Front Cardiovasc Med 2019; 6:72. [PMID: 31231661 PMCID: PMC6566127 DOI: 10.3389/fcvm.2019.00072] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/13/2019] [Indexed: 12/14/2022] Open
Abstract
Tissue engineered heart valve (TEHV) technology may overcome deficiencies of existing available heart valve substitutes. The pathway by which TEHVs will undergo development and regulatory approval has several challenges. In this communication, we review: (1) the regulatory framework for regulation of medical devices in general and substitute heart valves in particular; (2) the special challenges of preclinical testing using animal models for TEHV, emphasizing the International Standards Organization (ISO) guidelines in document 5840; and (3) considerations that suggest a translational roadmap to move TEHV forward from pre-clinical to clinical studies and clinical implementation.
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Affiliation(s)
- Benjamin L Zhang
- Department of Surgery, University of Minnesota, Minneapolis, MN, United States
| | - Richard W Bianco
- Department of Surgery, University of Minnesota, Minneapolis, MN, United States
| | - Frederick J Schoen
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
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22
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Boyd R, Parisi F, Kalfa D. State of the Art: Tissue Engineering in Congenital Heart Surgery. Semin Thorac Cardiovasc Surg 2019; 31:807-817. [PMID: 31176798 DOI: 10.1053/j.semtcvs.2019.05.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 05/28/2019] [Indexed: 12/17/2022]
Abstract
Congenital heart disease is the leading cause of death secondary to congenital abnormalities in the United States and the incidence has increased significantly over the last 50 years. For those defects requiring surgical repair, bioprosthetic xenografts, allografts, and synthetic materials have traditionally been used. However, none of these modalities offer the potential for growth and accommodation within the pediatric population. Tissue engineering has been an area of great interest in a variety of cardiac applications as an innovative solution to create a product that can grow and regenerate within the body over time. Over the last 30 years, the original tissue engineering paradigm of a scaffold seeded with cells and cultured in a bioreactor has been expanded upon to include innovative methods of decellularization and production of "off-the-shelf" tissue-engineered products capable of in situ host cell repopulation. Despite progress in conceptual design and promising clinical results, widespread use of tissue-engineered products remains limited due to both regulatory and ongoing scientific challenges. Here, we describe the current state of the art with regards to in vitro, in vivo, and in situ tissue engineering as applicable within the field of congenital heart surgery and provide a brief overview of challenges and future directions.
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Affiliation(s)
- Rebekah Boyd
- Division of Cardiac, Thoracic and Vascular Surgery, Section of Pediatric and Congenital Cardiac Surgery, New-York Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, New York, New York
| | - Frank Parisi
- Division of Cardiac, Thoracic and Vascular Surgery, Section of Pediatric and Congenital Cardiac Surgery, New-York Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, New York, New York
| | - David Kalfa
- Division of Cardiac, Thoracic and Vascular Surgery, Section of Pediatric and Congenital Cardiac Surgery, New-York Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, New York, New York.
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23
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Bui HT, Prawel DA, Harris KL, Li E, James SP. Development and Fabrication of Vapor Cross-Linked Hyaluronan-Polyethylene Interpenetrating Polymer Network as a Biomaterial. ACS APPLIED MATERIALS & INTERFACES 2019; 11:18930-18941. [PMID: 31063346 DOI: 10.1021/acsami.9b03437] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Flexible heart valve leaflets made from hyaluronan-enhanced linear low-density polyethylene interpenetrating polymeric network (HA-LLDPE IPN) films have been shown to provide good hemodynamics, but the resulting surfaces were not consistent; therefore, the present work tries to mitigate this problem by developing a vapor cross-linked HA-LLDPE IPN. Herein, the HA-LLDPE fabrication process is studied, and its parameters are varied to assess their effects on the IPN formation. Thermal analysis and gas chromatography-mass spectrometry were used to quantify the effects of different treatment conditions on material properties. Water contact angle goniometry, infrared spectroscopy, and toluidine blue O (TBO) staining were used to characterize the surface of the HA-LLDPE IPN. The results show that a hydrophilic surface is formed on HA-LLDPE, which is indicative of HA. HA surface density data from TBO staining show consistent HA distribution on the surface. The IPN fabrication process does not affect the tensile properties that make LLDPE an attractive material for use in flexible heart valve leaflets. The 28 day in vitro biological assays show HA-LLDPE to be noncytotoxic and resistant to enzymatic degradation. The HA-LLDPE showed less platelet adhesion and caused less platelet activation than the plain LLDPE or tissue culture polystyrene. All of the results indicate that vapor cross-linked HA-LLDPE IPN is a promising material for use as flexible leaflets for heart valve replacements.
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24
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Dai J, Qiao W, Shi J, Liu C, Hu X, Dong N. Modifying decellularized aortic valve scaffolds with stromal cell-derived factor-1α loaded proteolytically degradable hydrogel for recellularization and remodeling. Acta Biomater 2019; 88:280-292. [PMID: 30721783 DOI: 10.1016/j.actbio.2019.02.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 02/06/2023]
Abstract
Decellularized matrix is of great interest as a scaffold for the tissue engineering heart valves due to its naturally three-dimensional structure and bioactive composition. A primary challenge of tissue engineered heart valves based on decellularized matrix is to grow a physiologically appropriate cell population within the leaflet tissue. In this study, a composite scaffold was fabricated by the combination of a porous matrix metalloproteinase (MMP) degradable poly (ethylene glycol) (PEG) hydrogel that were loaded with stromal cell-derived factor-1α (SDF-1α) and a mechanically supportive decellularized porcine aortic valve. Results demonstrated that the modified scaffold enhanced bone marrow mesenchymal stem cells (BMSC) adhesion, viability and proliferation, and promoted BMSC differentiate into valve interstitial-like cells. Furthermore, these modifications lead to enhanced protection of the scaffold from thrombosis. In vivo assessment by rat subdermal model showed the modified scaffold was highly biocompatible with tissue remodeling characterized by promoting mesenchymal stem cells recruitment and facilitating M2 macrophage phenotype polarization. The surface layers of PEG hydrogel not only could provide a niche for cell migration, proliferation and differentiation, but also protect the scaffolds from rapid degeneration, inflammation and calcification. The intermediate layer of decellularized valve could maintain the organization of the scaffold and perform the valve function. The promising results emphasize the potential of our scaffolds to improve recellularization and promote remodeling of implanted decellularized valves. These findings suggest that the SDF-1α loaded MMP degradable PEG hydrogel modification could be an efficient approach to develop functional decellularized heart valve. STATEMENT OF SIGNIFICANCE: A composite scaffold was fabricated by the combination of a porous matrix metalloproteinase (MMP) degradable poly (ethylene glycol) (PEG) hydrogel that were loaded with SDF-1α and a mechanically supportive decellularized porcine aortic valve. The surface layers of PEG hydrogel not only could provide a niche for cell migration, proliferation and differentiation, but also protect the scaffolds from rapid degeneration, inflammation and calcification. The intermediate layer of decellularized valve could maintain the organization of the scaffold and perform the valve function. The promising results emphasize the ability of our scaffolds to improve recellularization and promote remodeling of implanted decellularized valves. This suggests that the extracellular matrix-based valve scaffolds have potential for clinical applications.
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Affiliation(s)
- Jinchi Dai
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Weihua Qiao
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Jiawei Shi
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Chungen Liu
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Xingjian Hu
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Nianguo Dong
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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25
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Gomel MA, Lee R, Grande-Allen KJ. Comparing the Role of Mechanical Forces in Vascular and Valvular Calcification Progression. Front Cardiovasc Med 2019; 5:197. [PMID: 30687719 PMCID: PMC6335252 DOI: 10.3389/fcvm.2018.00197] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 12/20/2018] [Indexed: 01/07/2023] Open
Abstract
Calcification is a prevalent disease in most fully developed countries and is predominantly observed in heart valves and nearby vasculature. Calcification of either tissue leads to deterioration and, ultimately, failure causing poor quality of life and decreased overall life expectancy in patients. In valves, calcification presents as Calcific Aortic Valve Disease (CAVD), in which the aortic valve becomes stenotic when calcific nodules form within the leaflets. The initiation and progression of these calcific nodules is strongly influenced by the varied mechanical forces on the valve. In turn, the addition of calcific nodules creates localized disturbances in the tissue biomechanics, which affects extracellular matrix (ECM) production and cellular activation. In vasculature, atherosclerosis is the most common occurrence of calcification. Atherosclerosis exhibits as calcific plaque formation that forms in juxtaposition to areas of low blood shear stresses. Research in these two manifestations of calcification remain separated, although many similarities persist. Both diseases show that the endothelial layer and its regulation of nitric oxide is crucial to calcification progression. Further, there are similarities between vascular smooth muscle cells and valvular interstitial cells in terms of their roles in ECM overproduction. This review summarizes valvular and vascular tissue in terms of their basic anatomy, their cellular and ECM components and mechanical forces. Calcification is then examined in both tissues in terms of disease prediction, progression, and treatment. Highlighting the similarities and differences between these areas will help target further research toward disease treatment.
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26
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Jover E, Fagnano M, Angelini G, Madeddu P. Cell Sources for Tissue Engineering Strategies to Treat Calcific Valve Disease. Front Cardiovasc Med 2018; 5:155. [PMID: 30460245 PMCID: PMC6232262 DOI: 10.3389/fcvm.2018.00155] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/10/2018] [Indexed: 12/15/2022] Open
Abstract
Cardiovascular calcification is an independent risk factor and an established predictor of adverse cardiovascular events. Despite concomitant factors leading to atherosclerosis and heart valve disease (VHD), the latter has been identified as an independent pathological entity. Calcific aortic valve stenosis is the most common form of VDH resulting of either congenital malformations or senile “degeneration.” About 2% of the population over 65 years is affected by aortic valve stenosis which represents a major cause of morbidity and mortality in the elderly. A multifactorial, complex and active heterotopic bone-like formation process, including extracellular matrix remodeling, osteogenesis and angiogenesis, drives heart valve “degeneration” and calcification, finally causing left ventricle outflow obstruction. Surgical heart valve replacement is the current therapeutic option for those patients diagnosed with severe VHD representing more than 20% of all cardiac surgeries nowadays. Tissue Engineering of Heart Valves (TEHV) is emerging as a valuable alternative for definitive treatment of VHD and promises to overcome either the chronic oral anticoagulation or the time-dependent deterioration and reintervention of current mechanical or biological prosthesis, respectively. Among the plethora of approaches and stablished techniques for TEHV, utilization of different cell sources may confer of additional properties, desirable and not, which need to be considered before moving from the bench to the bedside. This review aims to provide a critical appraisal of current knowledge about calcific VHD and to discuss the pros and cons of the main cell sources tested in studies addressing in vitro TEHV.
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Affiliation(s)
- Eva Jover
- Bristol Medical School (Translational Health Sciences), Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Marco Fagnano
- Bristol Medical School (Translational Health Sciences), Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Gianni Angelini
- Bristol Medical School (Translational Health Sciences), Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Paolo Madeddu
- Bristol Medical School (Translational Health Sciences), Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
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Feng L, Qi N, Gao H, Sun W, Vazquez M, Griffith BE, Luo X. On the chordae structure and dynamic behaviour of the mitral valve. IMA JOURNAL OF APPLIED MATHEMATICS 2018; 83:1066-1091. [PMID: 30655652 PMCID: PMC6328065 DOI: 10.1093/imamat/hxy035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 06/29/2018] [Accepted: 07/29/2018] [Indexed: 05/07/2023]
Abstract
We develop a fluid-structure interaction (FSI) model of the mitral valve (MV) that uses an anatomically and physiologically realistic description of the MV leaflets and chordae tendineae. Three different chordae models-complex, 'pseudo-fibre' and simplified chordae-are compared to determine how different chordae representations affect the dynamics of the MV. The leaflets and chordae are modelled as fibre-reinforced hyperelastic materials, and FSI is modelled using an immersed boundary-finite element method. The MV model is first verified under static boundary conditions against the commercial finite element software ABAQUS and then used to simulate MV dynamics under physiological pressure conditions. Interesting flow patterns and vortex formulation are observed in all three cases. To quantify the highly complex system behaviour resulting from FSI, an energy budget analysis of the coupled MV FSI model is performed. Results show that the complex and pseudo-fibre chordae models yield good valve closure during systole but that the simplified chordae model leads to poorer leaflet coaptation and an unrealistic bulge in the anterior leaflet belly. An energy budget analysis shows that the MV models with complex and pseudo-fibre chordae have similar energy distribution patterns but the MV model with the simplified chordae consumes more energy, especially during valve closing and opening. We find that the complex chordae and pseudo-fibre chordae have similar impact on the overall MV function but that the simplified chordae representation is less accurate. Because a pseudo-fibre chordal structure is easier to construct and less computationally intensive, it may be a good candidate for modelling MV dynamics or interaction between the MV and heart in patient-specific applications.
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Affiliation(s)
- Liuyang Feng
- School of Mathematics and Statistics, University of Glasgow, UK
| | - Nan Qi
- Institute of Marine Science and Technology, Shandong University, Shandong, China and School of Mathematics and Statistics, University of Glasgow, UK
| | - Hao Gao
- School of Mathematics and Statistics, University of Glasgow, UK
| | - Wei Sun
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - Boyce E Griffith
- Departments of Mathematics, Applied Physical Sciences, and Biomedical Engineering and McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
| | - Xiaoyu Luo
- School of Mathematics and Statistics, University of Glasgow, UK
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Rotman OM, Bianchi M, Ghosh RP, Kovarovic B, Bluestein D. Principles of TAVR valve design, modelling, and testing. Expert Rev Med Devices 2018; 15:771-791. [PMID: 30318937 PMCID: PMC6417919 DOI: 10.1080/17434440.2018.1536427] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Transcatheter aortic valve replacement (TAVR) has emerged as an effective minimally-invasive alternative to surgical valve replacement in medium- to high-risk, elderly patients with calcific aortic valve disease and severe aortic stenosis. The rapid growth of the TAVR devices market has led to a high variety of designs, each aiming to address persistent complications associated with TAVR valves that may hamper the anticipated expansion of TAVR utility. AREAS COVERED Here we outline the challenges and the technical demands that TAVR devices need to address for achieving the desired expansion, and review design aspects of selected, latest generation, TAVR valves of both clinically-used and investigational devices. We further review in detail some of the up-to-date modeling and testing approaches for TAVR, both computationally and experimentally, and additionally discuss those as complementary approaches to the ISO 5840-3 standard. A comprehensive survey of the prior and up-to-date literature was conducted to cover the most pertaining issues and challenges that TAVR technology faces. EXPERT COMMENTARY The expansion of TAVR over SAVR and to new indications seems more promising than ever. With new challenges to come, new TAV design approaches, and materials used, are expected to emerge, and novel testing/modeling methods to be developed.
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Affiliation(s)
- Oren M. Rotman
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Matteo Bianchi
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Ram P. Ghosh
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Brandon Kovarovic
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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29
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Rotman OM, Kovarovic B, Chiu WC, Bianchi M, Marom G, Slepian MJ, Bluestein D. Novel Polymeric Valve for Transcatheter Aortic Valve Replacement Applications: In Vitro Hemodynamic Study. Ann Biomed Eng 2018; 47:113-125. [PMID: 30194551 DOI: 10.1007/s10439-018-02119-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/17/2018] [Indexed: 11/30/2022]
Abstract
Transcatheter aortic valve replacement (TAVR) is a minimally-invasive approach for treating severe aortic stenosis. All clinically-used TAVR valves to date utilize chemically-fixed xenograft as the leaflet material. Inherent limitation of the tissue (e.g., calcific degeneration) motivates the search for alternative leaflet material. Here we introduce a novel polymeric TAVR valve that was designed to address the limitations of tissue-valves. In this study, we experimentally evaluated the hemodynamic performance of the valve and compared its performance to clinically-used valves: a gold standard surgical tissue valve, and a TAVR valve. Our comparative testing protocols included: (i) baseline hydrodynamics (ISO:5840-3), (ii) complementary patient-specific hydrodynamics in a dedicated system, and (iii) thrombogenicity. The patient-specific testing system facilitated comparing TAVR valves performance under more realistic conditions. Baseline hydrodynamics results at CO 4-7 L/min showed superior effective orifice area (EOA) for the polymer valve, most-notably as compared to the reference TAVR valve. Regurgitation fraction was higher in the polymeric valve, but within the ISO minimum requirements. Thrombogenicity trends followed the EOA results with the polymeric valve being the least thrombogenic, and clinical TAVR being the most. Hemodynamic-wise, the results strongly indicate that our polymeric TAVR valve can outperform tissue valves.
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Affiliation(s)
- Oren M Rotman
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA
| | - Brandon Kovarovic
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA
| | - Wei-Che Chiu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA
| | - Matteo Bianchi
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA
| | - Gil Marom
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA.,School of Mechanical Engineering, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Marvin J Slepian
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, 85721, USA
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA.
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Kheradvar A, Zareian R, Kawauchi S, Goodwin RL, Rugonyi S. Animal Models for Heart Valve Research and Development. ACTA ACUST UNITED AC 2018; 24:55-62. [PMID: 30631375 DOI: 10.1016/j.ddmod.2018.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Valvular heart disease is the third-most common cause of heart problems in the United States. Malfunction of the valves can be acquired or congenital and each may lead either to stenosis or regurgitation, or even both in some cases. Heart valve disease is a progressive disease, which is irreversible and may be fatal if left untreated. Pharmacological agents cannot currently prevent valvular calcification or help repair damaged valves, as valve tissue is unable to regenerate spontaneously. Thus, heart valve replacement/repair is the only current available treatment. Heart valve research and development is currently focused on two parallel paths; first, research that aims to understand the underlying mechanisms for heart valve disease to emerge with an ultimate goal to devise medical treatment; and second, efforts to develop repair and replacement options for a diseased valve. Studies that focus on developmental malformation, genetic and disease epigenetics usually employ small animal models that are easy to access for in vivo imaging that minimally disturbs their environment during early stages of development. Alternatively, studies that aim to develop novel device for replacement and repair of diseased valves often employ large animals whose heart size and anatomy closely replicate human's. This paper aims to briefly review the current state-of-the-art animal models, and justification to use an animal model for a particular heart valve related project.
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31
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Cardiovascular tissue engineering: From basic science to clinical application. Exp Gerontol 2018; 117:1-12. [PMID: 29604404 DOI: 10.1016/j.exger.2018.03.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/26/2018] [Indexed: 12/20/2022]
Abstract
Valvular heart disease is an increasing population health problem and, especially in the elderly, a significant cause of morbidity and mortality. The current treatment options, such as mechanical and bioprosthetic heart valve replacements, have significant restrictions and limitations. Considering the increased life expectancy of our aging population, there is an urgent need for novel heart valve concepts that remain functional throughout life to prevent the need for reoperation. Heart valve tissue engineering aims to overcome these constraints by creating regenerative, self-repairing valve substitutes with life-long durability. In this review, we give an overview of advances in the development of tissue engineered heart valves, and describe the steps required to design and validate a novel valve prosthesis before reaching first-in-men clinical trials. In-silico and in-vitro models are proposed as tools for the assessment of valve design, functionality and compatibility, while in-vivo preclinical models are required to confirm the remodeling and growth potential of the tissue engineered heart valves. An overview of the tissue engineered heart valve studies that have reached clinical translation is also presented. Final remarks highlight the possibilities as well as the obstacles to overcome in translating heart valve prostheses into clinical application.
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32
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Drach A, Khalighi AH, Sacks MS. A comprehensive pipeline for multi-resolution modeling of the mitral valve: Validation, computational efficiency, and predictive capability. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:10.1002/cnm.2921. [PMID: 28776326 PMCID: PMC5797517 DOI: 10.1002/cnm.2921] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/26/2017] [Accepted: 07/28/2017] [Indexed: 05/18/2023]
Abstract
Multiple studies have demonstrated that the pathological geometries unique to each patient can affect the durability of mitral valve (MV) repairs. While computational modeling of the MV is a promising approach to improve the surgical outcomes, the complex MV geometry precludes use of simplified models. Moreover, the lack of complete in vivo geometric information presents significant challenges in the development of patient-specific computational models. There is thus a need to determine the level of detail necessary for predictive MV models. To address this issue, we have developed a novel pipeline for building attribute-rich computational models of MV with varying fidelity directly from the in vitro imaging data. The approach combines high-resolution geometric information from loaded and unloaded states to achieve a high level of anatomic detail, followed by mapping and parametric embedding of tissue attributes to build a high-resolution, attribute-rich computational models. Subsequent lower resolution models were then developed and evaluated by comparing the displacements and surface strains to those extracted from the imaging data. We then identified the critical levels of fidelity for building predictive MV models in the dilated and repaired states. We demonstrated that a model with a feature size of about 5 mm and mesh size of about 1 mm was sufficient to predict the overall MV shape, stress, and strain distributions with high accuracy. However, we also noted that more detailed models were found to be needed to simulate microstructural events. We conclude that the developed pipeline enables sufficiently complex models for biomechanical simulations of MV in normal, dilated, repaired states.
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Affiliation(s)
- Andrew Drach
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Amir H Khalighi
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Michael S Sacks
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
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33
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Khalighi AH, Drach A, Gorman RC, Gorman JH, Sacks MS. Multi-resolution geometric modeling of the mitral heart valve leaflets. Biomech Model Mechanobiol 2017; 17:351-366. [PMID: 28983742 DOI: 10.1007/s10237-017-0965-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
Abstract
An essential element of cardiac function, the mitral valve (MV) ensures proper directional blood flow between the left heart chambers. Over the past two decades, computational simulations have made marked advancements toward providing powerful predictive tools to better understand valvular function and improve treatments for MV disease. However, challenges remain in the development of robust means for the quantification and representation of MV leaflet geometry. In this study, we present a novel modeling pipeline to quantitatively characterize and represent MV leaflet surface geometry. Our methodology utilized a two-part additive decomposition of the MV geometric features to decouple the macro-level general leaflet shape descriptors from the leaflet fine-scale features. First, the general shapes of five ovine MV leaflets were modeled using superquadric surfaces. Second, the finer-scale geometric details were captured, quantified, and reconstructed via a 2D Fourier analysis with an additional sparsity constraint. This spectral approach allowed us to easily control the level of geometric details in the reconstructed geometry. The results revealed that our methodology provided a robust and accurate approach to develop MV-specific models with an adjustable level of spatial resolution and geometric detail. Such fully customizable models provide the necessary means to perform computational simulations of the MV at a range of geometric accuracies in order to identify the level of complexity required to achieve predictive MV simulations.
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Affiliation(s)
- Amir H Khalighi
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Andrew Drach
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael S Sacks
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA.
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Gao H, Qi N, Feng L, Ma X, Danton M, Berry C, Luo X. Modelling mitral valvular dynamics-current trend and future directions. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33:e2858. [PMID: 27935265 PMCID: PMC5697636 DOI: 10.1002/cnm.2858] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 09/30/2016] [Accepted: 11/26/2016] [Indexed: 05/19/2023]
Abstract
Dysfunction of mitral valve causes morbidity and premature mortality and remains a leading medical problem worldwide. Computational modelling aims to understand the biomechanics of human mitral valve and could lead to the development of new treatment, prevention and diagnosis of mitral valve diseases. Compared with the aortic valve, the mitral valve has been much less studied owing to its highly complex structure and strong interaction with the blood flow and the ventricles. However, the interest in mitral valve modelling is growing, and the sophistication level is increasing with the advanced development of computational technology and imaging tools. This review summarises the state-of-the-art modelling of the mitral valve, including static and dynamics models, models with fluid-structure interaction, and models with the left ventricle interaction. Challenges and future directions are also discussed.
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Affiliation(s)
- Hao Gao
- School of Mathematics and StatisticsUniversity of GlasgowUK
| | - Nan Qi
- School of Mathematics and StatisticsUniversity of GlasgowUK
| | - Liuyang Feng
- School of Mathematics and StatisticsUniversity of GlasgowUK
| | | | - Mark Danton
- Department of Cardiac SurgeryRoyal Hospital for ChildrenGlasgowUK
| | - Colin Berry
- Institute of Cardiovascular and Medical SciencesUniversity of GlasgowUK
| | - Xiaoyu Luo
- School of Mathematics and StatisticsUniversity of GlasgowUK
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35
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Usprech J, Romero DA, Amon CH, Simmons CA. Combinatorial screening of 3D biomaterial properties that promote myofibrogenesis for mesenchymal stromal cell-based heart valve tissue engineering. Acta Biomater 2017; 58:34-43. [PMID: 28532900 DOI: 10.1016/j.actbio.2017.05.044] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/16/2017] [Accepted: 05/18/2017] [Indexed: 01/13/2023]
Abstract
The physical and chemical properties of a biomaterial integrate with soluble cues in the cell microenvironment to direct cell fate and function. Predictable biomaterial-based control of integrated cell responses has been investigated with two-dimensional (2D) screening platforms, but integrated responses in 3D have largely not been explored systematically. To address this need, we developed a screening platform using polyethylene glycol norbornene (PEG-NB) as a model biomaterial with which the polymer wt% (to control elastic modulus) and adhesion peptide types (RGD, DGEA, YIGSR) and densities could be controlled independently and combinatorially in arrays of 3D hydrogels. We applied this platform and regression modeling to identify combinations of biomaterial and soluble biochemical (TGF-β1) factors that best promoted myofibrogenesis of human mesenchymal stromal cells (hMSCs) in order to inform our understanding of regenerative processes for heart valve tissue engineering. In contrast to 2D culture, our screens revealed that soft hydrogels (low PEG-NB wt%) best promoted spread myofibroblastic cells that expressed high levels of α-smooth muscle actin (α-SMA) and collagen type I. High concentrations of RGD enhanced α-SMA expression in the presence of TGF-β1 and cell spreading regardless of whether TGF-β1 was in the culture medium. Strikingly, combinations of peptides that maximized collagen expression depended on the presence or absence of TGF-β1, indicating that biomaterial properties can modulate MSC response to soluble signals. This combination of a 3D biomaterial array screening platform with statistical modeling is broadly applicable to systematically identify combinations of biomaterial and microenvironmental conditions that optimally guide cell responses. STATEMENT OF SIGNIFICANCE We present a novel screening platform and methodology to model and identify how combinations of biomaterial and microenvironmental conditions guide cell phenotypes in 3D. Our approach to systematically identify complex relationships between microenvironmental cues and cell responses enables greater predictive power over cell fate in conditions with interacting material design factors. We demonstrate that this approach not only predicts that mesenchymal stromal cell (MSC) myofibrogenesis is promoted by soft, porous 3D biomaterials, but also generated new insights which demonstrate how biomaterial properties can differentially modulate MSC response to soluble signals. An additional benefit of the process includes utilizing both parametric and non parametric analyses which can demonstrate dominant significant trends as well as subtle interactions between biochemical and biomaterial cues.
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36
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Gao H, Feng L, Qi N, Berry C, Griffith BE, Luo X. A coupled mitral valve-left ventricle model with fluid-structure interaction. Med Eng Phys 2017; 47:128-136. [PMID: 28751011 PMCID: PMC6779302 DOI: 10.1016/j.medengphy.2017.06.042] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 06/13/2017] [Accepted: 06/24/2017] [Indexed: 12/16/2022]
Abstract
Understanding the interaction between the valves and walls of the heart is important in assessing and subsequently treating heart dysfunction. This study presents an integrated model of the mitral valve (MV) coupled to the left ventricle (LV), with the geometry derived from in vivo clinical magnetic resonance images. Numerical simulations using this coupled MV-LV model are developed using an immersed boundary/finite element method. The model incorporates detailed valvular features, left ventricular contraction, nonlinear soft tissue mechanics, and fluid-mediated interactions between the MV and LV wall. We use the model to simulate cardiac function from diastole to systole. Numerically predicted LV pump function agrees well with in vivo data of the imaged healthy volunteer, including the peak aortic flow rate, the systolic ejection duration, and the LV ejection fraction. In vivo MV dynamics are qualitatively captured. We further demonstrate that the diastolic filling pressure increases significantly with impaired myocardial active relaxation to maintain a normal cardiac output. This is consistent with clinical observations. The coupled model has the potential to advance our fundamental knowledge of mechanisms underlying MV-LV interaction, and help in risk stratification and optimisation of therapies for heart diseases.
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Affiliation(s)
- Hao Gao
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK.
| | - Liuyang Feng
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
| | - Nan Qi
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
| | - Colin Berry
- Institute of Cardiovascular and Medical Science, University of Glasgow, Glasgow, UK
| | - Boyce E Griffith
- Departments of Mathematics and Biomedical Engineering and McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
| | - Xiaoyu Luo
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
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37
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Luraghi G, Wu W, De Gaetano F, Rodriguez Matas JF, Moggridge GD, Serrani M, Stasiak J, Costantino ML, Migliavacca F. Evaluation of an aortic valve prosthesis: Fluid-structure interaction or structural simulation? J Biomech 2017; 58:45-51. [PMID: 28454910 PMCID: PMC5473331 DOI: 10.1016/j.jbiomech.2017.04.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/23/2017] [Accepted: 04/09/2017] [Indexed: 01/31/2023]
Abstract
Bio-inspired polymeric heart valves (PHVs) are excellent candidates to mimic the structural and the fluid dynamic features of the native valve. PHVs can be implanted as prosthetic alternative to currently clinically used mechanical and biological valves or as potential candidate for a minimally invasive treatment, like the transcatheter aortic valve implantation. Nevertheless, PHVs are not currently used for clinical applications due to their lack of reliability. In order to investigate the main features of this new class of prostheses, pulsatile tests in an in-house pulse duplicator were carried out and reproduced in silico with both structural Finite-Element (FE) and Fluid-Structure interaction (FSI) analyses. Valve kinematics and geometric orifice area (GOA) were evaluated to compare the in vitro and the in silico tests. Numerical results showed better similarity with experiments for the FSI than for the FE simulations. The maximum difference between experimental and FSI GOA at maximum opening time was only 5%, as compared to the 46.5% between experimental and structural FE GOA. The stress distribution on the valve leaflets clearly reflected the difference in valve kinematics. Higher stress values were found in the FSI simulations with respect to those obtained in the FE simulation. This study demonstrates that FSI simulations are more appropriate than FE simulations to describe the actual behaviour of PHVs as they can replicate the valve-fluid interaction while providing realistic fluid dynamic results.
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Affiliation(s)
- Giulia Luraghi
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Wei Wu
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Francesco De Gaetano
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Josè Felix Rodriguez Matas
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Geoff D Moggridge
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Marta Serrani
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Joanna Stasiak
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Maria Laura Costantino
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Francesco Migliavacca
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy.
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38
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Sanders B, Driessen-Mol A, Bouten CVC, Baaijens FPT. The Effects of Scaffold Remnants in Decellularized Tissue-Engineered Cardiovascular Constructs on the Recruitment of Blood Cells<sup/>. Tissue Eng Part A 2017; 23:1142-1151. [PMID: 28314377 PMCID: PMC5652973 DOI: 10.1089/ten.tea.2016.0503] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Decellularized tissue-engineered heart valves (DTEHVs) showed remarkable results in translational animal models, leading to recellularization within hours after implantation. This is crucial to enable tissue remodeling. To investigate if the presence of scaffold remnants before implantation is responsible for the fast recellularization of DTEHVs, an in vitro mesofluidic system was used. Human granulocyte and agranulocyte fractions were isolated, stained, brought back in suspension, and implemented in the system. Three different types of biomaterials were exposed to the circulating blood cells, consisting of decellularized tissue-engineered constructs (DTECs) with or without scaffold remnants or only bare scaffold. After 5 h of testing, the granulocyte fraction depleted faster from the circulation than the agranulocyte fraction. However, only granulocytes infiltrated into the DTEC with scaffold, migrating toward the scaffold remnants. The agranulocyte population, on the other hand, was only observed on the outer surface. Active cell infiltration was associated with increased levels of matrix metalloproteinase-1 secretion in the DTEC, including scaffold remnants. Proinflammatory cytokines such as interleukin (IL)-1α, IL-6, and tumor necrosis factor alpha (TNFα) were significantly upregulated in the DTEC without scaffold remnants. These results indicate that scaffold remnants can influence the immune response in DTEC, being responsible for rapid cell infiltration.
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Affiliation(s)
- Bart Sanders
- 1 Department of Biomedical Engineering, Eindhoven University of Technology , Eindhoven, The Netherlands .,2 Institute for Complex Molecular Systems, Eindhoven University of Technology , Eindhoven, The Netherlands
| | - Anita Driessen-Mol
- 1 Department of Biomedical Engineering, Eindhoven University of Technology , Eindhoven, The Netherlands .,2 Institute for Complex Molecular Systems, Eindhoven University of Technology , Eindhoven, The Netherlands
| | - Carlijn V C Bouten
- 1 Department of Biomedical Engineering, Eindhoven University of Technology , Eindhoven, The Netherlands .,2 Institute for Complex Molecular Systems, Eindhoven University of Technology , Eindhoven, The Netherlands
| | - Frank P T Baaijens
- 1 Department of Biomedical Engineering, Eindhoven University of Technology , Eindhoven, The Netherlands .,2 Institute for Complex Molecular Systems, Eindhoven University of Technology , Eindhoven, The Netherlands
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39
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Wang ZC, Yuan Q, Zhu HW, Shen BS, Tang D. Computational Modeling for Fluid–Structure Interaction of Bioprosthetic Heart Valve with Different Suture Density: Comparison with Dynamic Structure Simulation. INT J PATTERN RECOGN 2017. [DOI: 10.1142/s0218001417570075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this paper, a parametric geometry model based on elliptic and conic surfaces was developed for bioprosthetic heart valve (BHV) simulation. The valve material was modeled by a hyperelastic nonlinear anisotropic solid model. Different suture densities could be substituted by various bonded points between artery vessel and the leaflets as boundary conditions in the computational modeling. Besides these two assumptions that dynamic structure (DS) and fluid–structure interaction (FSI) both shared, the latter need incompressible viscous Newton fluid model to depict bloodstream passing through the BHV. Immersed boundary (IB) method was introduced to solve the FSI simulation. In addition, the DS analysis applied transvalvular pressure on the valve while FSI had left ventricular pressure on fluid inlet as initials. There was inconsistency between the moments of the maximum deformation and the maximum loading in both simulations. Although a similar trend of deformation lagging the load was viewed, the extent of delay in FSI was much smaller compared with that in DS simulation. The deformed profiles in cross-sectional views were shown in one picture to illustrate different dynamic responses caused by distinct assumptions. Percent of open area at the moments when the maximum deformation occurred was defined to show which calculation achieved better approximation for precise hemodynamics. Fixed point was given as boundaries between BHV and artery in the modeling part. Calculations showed that the more the fixed points in this bonded contact, the lower the principal stress was. The maximum shear stress showed a different trend. It had a different trend. Stress concentration in the conjunction area made it high-risk to be teared. Different suture densities had significant impaction in FSI simulations. With that analysis our work achieved a more comprehensive simulation to describe true hemodynamics of a BHV implanted in artery. The artery vessel had particular dynamic response under such assumptions, gradient existed in the maximum principal stress distribution diagram, from inner wall through which blood passing to the outer wall. Results showed a large suture density was suggested in BHV implantation.
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Affiliation(s)
- Z. C. Wang
- School of Mechanical Engineering Shandong University, Key Laboratory of High-efficiency and Clean Mechanical Manufacture, (Shandong University) Ministry of Education, Jinan, P. R. China
| | - Q. Yuan
- School of Mechanical Engineering Shandong University, Key Laboratory of High-efficiency and Clean Mechanical Manufacture, (Shandong University) Ministry of Education, Jinan, P. R. China
| | - H. W. Zhu
- School of Mechanical Engineering Shandong University, Key Laboratory of High-efficiency and Clean Mechanical Manufacture, (Shandong University) Ministry of Education, Jinan, P. R. China
| | - B. S. Shen
- School of Mechanical Engineering Shandong University, Key Laboratory of High-efficiency and Clean Mechanical Manufacture, (Shandong University) Ministry of Education, Jinan, P. R. China
| | - D. Tang
- School of Mechanical Engineering Shandong University, Key Laboratory of High-efficiency and Clean Mechanical Manufacture, (Shandong University) Ministry of Education, Jinan, P. R. China
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40
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Fioretta ES, Dijkman PE, Emmert MY, Hoerstrup SP. The future of heart valve replacement: recent developments and translational challenges for heart valve tissue engineering. J Tissue Eng Regen Med 2017; 12:e323-e335. [PMID: 27696730 DOI: 10.1002/term.2326] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 07/25/2016] [Accepted: 09/26/2016] [Indexed: 12/18/2022]
Abstract
Heart valve replacement is often the only solution for patients suffering from valvular heart disease. However, currently available valve replacements require either life-long anticoagulation or are associated with valve degeneration and calcification. Moreover, they are suboptimal for young patients, because they do not adapt to the somatic growth. Tissue-engineering has been proposed as a promising approach to fulfil the urgent need for heart valve replacements with regenerative and growth capacity. This review will start with an overview on the currently available valve substitutes and the techniques for heart valve replacement. The main focus will be on the evolution of and different approaches for heart valve tissue engineering, namely the in vitro, in vivo and in situ approaches. More specifically, several heart valve tissue-engineering studies will be discussed with regard to their shortcomings or successes and their possible suitability for novel minimally invasive implantation techniques. As in situ heart valve tissue engineering based on cell-free functionalized starter materials is considered to be a promising approach for clinical translation, this review will also analyse the techniques used to tune the inflammatory response and cell recruitment upon implantation in order to stir a favourable outcome: controlling the blood-material interface, regulating the cytokine release, and influencing cell adhesion and differentiation. In the last section, the authors provide their opinion about the future developments and the challenges towards clinical translation and adaptation of heart valve tissue engineering for valve replacement. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Emanuela S Fioretta
- Institute for Regenerative Medicine (IREM), University of Zurich, Switzerland
| | - Petra E Dijkman
- Institute for Regenerative Medicine (IREM), University of Zurich, Switzerland
| | - Maximilian Y Emmert
- Institute for Regenerative Medicine (IREM), University of Zurich, Switzerland.,Heart Center Zurich, University Hospital Zurich, Switzerland.,Wyss Translational Center Zurich, Switzerland
| | - Simon P Hoerstrup
- Institute for Regenerative Medicine (IREM), University of Zurich, Switzerland.,Wyss Translational Center Zurich, Switzerland.,Department of Biomedical Engineering, Eindhoven University of Technology, The Netherlands
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41
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Wu S, Duan B, Qin X, Butcher JT. Living nano-micro fibrous woven fabric/hydrogel composite scaffolds for heart valve engineering. Acta Biomater 2017; 51:89-100. [PMID: 28110071 DOI: 10.1016/j.actbio.2017.01.051] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/27/2016] [Accepted: 01/17/2017] [Indexed: 02/07/2023]
Abstract
Regeneration and repair of injured or diseased heart valves remains a clinical challenge. Tissue engineering provides a promising treatment approach to facilitate living heart valve repair and regeneration. Three-dimensional (3D) biomimetic scaffolds that possess heterogeneous and anisotropic features that approximate those of native heart valve tissue are beneficial to the successful in vitro development of tissue engineered heart valves (TEHV). Here we report the development and characterization of a novel composite scaffold consisting of nano- and micro-scale fibrous woven fabrics and 3D hydrogels by using textile techniques combined with bioactive hydrogel formation. Embedded nano-micro fibrous scaffolds within hydrogel enhanced mechanical strength and physical structural anisotropy of the composite scaffold (similar to native aortic valve leaflets) and also reduced its compaction. We determined that the composite scaffolds supported the growth of human aortic valve interstitial cells (HAVIC), balanced the remodeling of heart valve ECM against shrinkage, and maintained better physiological fibroblastic phenotype in both normal and diseased HAVIC over single materials. These fabricated composite scaffolds enable the engineering of a living heart valve graft with improved anisotropic structure and tissue biomechanics important for maintaining valve cell phenotypes. STATEMENT OF SIGNIFICANCE Heart valve-related disease is an important clinical problem, with over 300,000 surgical repairs performed annually. Tissue engineering offers a promising strategy for heart valve repair and regeneration. In this study, we developed and tissue engineered living nano-micro fibrous woven fabric/hydrogel composite scaffolds by using textile technique combined with bioactive hydrogel formation. The novelty of our technique is that the composite scaffolds can mimic physical structure anisotropy and the mechanical strength of natural aortic valve leaflet. Moreover, the composite scaffolds prevented the matrix shrinkage, which is major problem that causes the failure of TEHV, and better maintained physiological fibroblastic phenotype in both normal and diseased HAVIC. This work marks the first report of a combination composite scaffold using 3D hydrogel enhanced by nano-micro fibrous woven fabric, and represents a promising tissue engineering strategy to treat heart valve injury.
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Dasi LP, Hatoum H, Kheradvar A, Zareian R, Alavi SH, Sun W, Martin C, Pham T, Wang Q, Midha PA, Raghav V, Yoganathan AP. On the Mechanics of Transcatheter Aortic Valve Replacement. Ann Biomed Eng 2017; 45:310-331. [PMID: 27873034 PMCID: PMC5300937 DOI: 10.1007/s10439-016-1759-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/03/2016] [Indexed: 01/22/2023]
Abstract
Transcatheter aortic valves (TAVs) represent the latest advances in prosthetic heart valve technology. TAVs are truly transformational as they bring the benefit of heart valve replacement to patients that would otherwise not be operated on. Nevertheless, like any new device technology, the high expectations are dampened with growing concerns arising from frequent complications that develop in patients, indicating that the technology is far from being mature. Some of the most common complications that plague current TAV devices include malpositioning, crimp-induced leaflet damage, paravalvular leak, thrombosis, conduction abnormalities and prosthesis-patient mismatch. In this article, we provide an in-depth review of the current state-of-the-art pertaining the mechanics of TAVs while highlighting various studies guiding clinicians, regulatory agencies, and next-generation device designers.
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Affiliation(s)
- Lakshmi P Dasi
- Department of Biomedical Engineering, Dorothy Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Avenue, Columbus, OH, 43210, USA.
| | - Hoda Hatoum
- Department of Biomedical Engineering, Dorothy Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Avenue, Columbus, OH, 43210, USA
| | - Arash Kheradvar
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology, Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA
| | - Ramin Zareian
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology, Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA
| | - S Hamed Alavi
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology, Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA
| | - Wei Sun
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Caitlin Martin
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Thuy Pham
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Qian Wang
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Prem A Midha
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Vrishank Raghav
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Ajit P Yoganathan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
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Xue Y, Sant V, Phillippi J, Sant S. Biodegradable and biomimetic elastomeric scaffolds for tissue-engineered heart valves. Acta Biomater 2017; 48:2-19. [PMID: 27780764 DOI: 10.1016/j.actbio.2016.10.032] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 10/13/2016] [Accepted: 10/22/2016] [Indexed: 01/04/2023]
Abstract
Valvular heart diseases are the third leading cause of cardiovascular disease, resulting in more than 25,000 deaths annually in the United States. Heart valve tissue engineering (HVTE) has emerged as a putative treatment strategy such that the designed construct would ideally withstand native dynamic mechanical environment, guide regeneration of the diseased tissue and more importantly, have the ability to grow with the patient. These desired functions could be achieved by biomimetic design of tissue-engineered constructs that recapitulate in vivo heart valve microenvironment with biomimetic architecture, optimal mechanical properties and possess suitable biodegradability and biocompatibility. Synthetic biodegradable elastomers have gained interest in HVTE due to their excellent mechanical compliance, controllable chemical structure and tunable degradability. This review focuses on the state-of-art strategies to engineer biomimetic elastomeric scaffolds for HVTE. We first discuss the various types of biodegradable synthetic elastomers and their key properties. We then highlight tissue engineering approaches to recreate some of the features in the heart valve microenvironment such as anisotropic and hierarchical tri-layered architecture, mechanical anisotropy and biocompatibility. STATEMENT OF SIGNIFICANCE Heart valve tissue engineering (HVTE) is of special significance to overcome the drawbacks of current valve replacements. Although biodegradable synthetic elastomers have emerged as promising materials for HVTE, a mature HVTE construct made from synthetic elastomers for clinical use remains to be developed. Hence, this review summarized various types of biodegradable synthetic elastomers and their key properties. The major focus that distinguishes this review from the current literature is the thorough discussion on the key features of native valve microenvironments and various up-and-coming approaches to engineer synthetic elastomers to recreate these features such as anisotropic tri-layered architecture, mechanical anisotropy, biodegradability and biocompatibility. This review is envisioned to inspire and instruct the design of functional HVTE constructs and facilitate their clinical translation.
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44
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Rahmani B, Tzamtzis S, Sheridan R, Mullen MJ, Yap J, Seifalian AM, Burriesci G. In Vitro Hydrodynamic Assessment of a New Transcatheter Heart Valve Concept (the TRISKELE). J Cardiovasc Transl Res 2016; 10:104-115. [PMID: 28028692 PMCID: PMC5437138 DOI: 10.1007/s12265-016-9722-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 11/21/2016] [Indexed: 11/01/2022]
Abstract
This study presents the in vitro hydrodynamic assessment of the TRISKELE, a new system suitable for transcatheter aortic valve implantation (TAVI), aiming to mitigate the procedural challenges experienced with current technologies. The TRISKELE valve comprises three polymeric leaflet and an adaptive sealing cuff, supported by a novel fully retrievable self-expanding nitinol wire frame. Valve prototypes were manufactured in three sizes of 23, 26, and 29 mm by automated dip-coating of a biostable polymer, and tested in a hydrodynamic bench setup in mock aortic roots of 21, 23, 25, and 27 mm annulus, and compared to two reference valves suitable for equivalent implantation ranges: Edwards SAPIEN XT and Medtronic CoreValve. The TRISKELE valves demonstrated a global hydrodynamic performance comparable or superior to the controls with significant reduction in paravalvular leakage. The TRISKELE valve exhibits enhanced anchoring and improved sealing. The valve is currently under preclinical investigation.
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Affiliation(s)
- Benyamin Rahmani
- Cardiovascular Engineering Laboratory, UCL Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Spyros Tzamtzis
- Cardiovascular Engineering Laboratory, UCL Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Rose Sheridan
- Cardiovascular Engineering Laboratory, UCL Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Michael J Mullen
- Barts Health NHS Trust, University College London Hospital, London, UK
| | - John Yap
- Barts Health NHS Trust, University College London Hospital, London, UK
| | | | - Gaetano Burriesci
- Cardiovascular Engineering Laboratory, UCL Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK. .,Ri.MED Foundation, Bioengineering Group, Palermo, Italy.
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45
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A Tri-Leaflet Nitinol Mesh Scaffold for Engineering Heart Valves. Ann Biomed Eng 2016; 45:413-426. [DOI: 10.1007/s10439-016-1778-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 12/09/2016] [Indexed: 01/03/2023]
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46
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Serrani M, Brubert J, Stasiak J, De Gaetano F, Zaffora A, Costantino ML, Moggridge GD. A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis. J Biomech Eng 2016; 138:061001. [PMID: 27018454 DOI: 10.1115/1.4033178] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Indexed: 11/08/2022]
Abstract
Styrene-based block copolymers are promising materials for the development of a polymeric heart valve prosthesis (PHV), and the mechanical properties of these polymers can be tuned via the manufacturing process, orienting the cylindrical domains to achieve material anisotropy. The aim of this work is the development of a computational tool for the optimization of the material microstructure in a new PHV intended for aortic valve replacement to enhance the mechanical performance of the device. An iterative procedure was implemented to orient the cylinders along the maximum principal stress direction of the leaflet. A numerical model of the leaflet was developed, and the polymer mechanical behavior was described by a hyperelastic anisotropic constitutive law. A custom routine was implemented to align the cylinders with the maximum principal stress direction in the leaflet for each iteration. The study was focused on valve closure, since during this phase the fibrous structure of the leaflets must bear the greatest load. The optimal microstructure obtained by our procedure is characterized by mainly circumferential orientation of the cylinders within the valve leaflet. An increase in the radial strain and a decrease in the circumferential strain due to the microstructure optimization were observed. Also, a decrease in the maximum value of the strain energy density was found in the case of optimized orientation; since the strain energy density is a widely used criterion to predict elastomer's lifetime, this result suggests a possible increase of the device durability if the polymer microstructure is optimized. The present method represents a valuable tool for the design of a new anisotropic PHV, allowing the investigation of different designs, materials, and loading conditions.
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47
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Liberski AR, Raynaud CM, Ayad N, Wojciechowska D, Sathappan A. Valve Tissue Engineering with Living Absorbable Threads. Macromol Biosci 2016; 17. [PMID: 27615551 DOI: 10.1002/mabi.201600196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/04/2016] [Indexed: 11/10/2022]
Abstract
Tissue engineering (TE) depends on the population of scaffolds with appropriate cells, arranged in a specific physiological direction using a variety of techniques. Here, a novel technique of creating "living threads" is described based on thin (poly(ε-caprolactone) fibers of different diameters (23-243 μm). The fibers readily attract human mesenchymal stem cells (MSCs), which are firmly adhered. These versatile fibers can be used to produce dimensional shapes identical in shape to the cup-like structure of a normal human valve, while preserving the specific orientation of both the cells and the fibers. The MSCs on leaflets and the cells cultured in flask shown similar epitopes expression when analyzed by fluorescence activated cell sorting. Together, these characteristics have important functional implications as living absorbable fibers can be a valuable resource in TE of living tissues, including heart valves.
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Affiliation(s)
| | | | - Nadia Ayad
- Mechanical Engineering and Material Science Department, Military Institute of Engineering (IME), Rio de Janeiro, RJ, 22291-270, Brazil
| | - Dorota Wojciechowska
- Department of Material and Commodity Sciences and Textile Metrology, Lodz University of Technology, ul. Zeromskiego 116, 90-924, Lodz, Poland
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48
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Coombs KE, Leonard AT, Rush MN, Santistevan DA, Hedberg-Dirk EL. Isolated effect of material stiffness on valvular interstitial cell differentiation. J Biomed Mater Res A 2016; 105:51-61. [DOI: 10.1002/jbm.a.35864] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 08/05/2016] [Indexed: 01/03/2023]
Affiliation(s)
- Kent E. Coombs
- Center for Biomedical Engineering; University of New Mexico; Albuquerque New Mexico
- Biomedical Sciences Graduate Program; University of New Mexico; Albuquerque New Mexico
| | - Alexander T. Leonard
- Center for Biomedical Engineering; University of New Mexico; Albuquerque New Mexico
- Department of Chemical and Biological Engineering; University of New Mexico; Albuquerque New Mexico
| | - Matthew N. Rush
- Center for Biomedical Engineering; University of New Mexico; Albuquerque New Mexico
- Nanoscience and Microsystems Engineering; University of New Mexico; Albuquerque New Mexico
| | - David A. Santistevan
- Center for Biomedical Engineering; University of New Mexico; Albuquerque New Mexico
| | - Elizabeth L. Hedberg-Dirk
- Center for Biomedical Engineering; University of New Mexico; Albuquerque New Mexico
- Department of Chemical and Biological Engineering; University of New Mexico; Albuquerque New Mexico
- Nanoscience and Microsystems Engineering; University of New Mexico; Albuquerque New Mexico
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49
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Tissue-Engineered Tubular Heart Valves Combining a Novel Precontraction Phase with the Self-Assembly Method. Ann Biomed Eng 2016; 45:427-438. [DOI: 10.1007/s10439-016-1708-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/04/2016] [Indexed: 11/25/2022]
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50
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Schoen FJ. Morphology, Clinicopathologic Correlations, and Mechanisms in Heart Valve Health and Disease. Cardiovasc Eng Technol 2016; 9:126-140. [PMID: 27502286 DOI: 10.1007/s13239-016-0277-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 07/28/2016] [Indexed: 10/21/2022]
Abstract
The clinical and pathological features of the most frequent intrinsic structural diseases that affect the heart valves are well established, but heart valve disease mechanisms are poorly understood, and effective treatment options are evolving. Major advances in the understanding of the structure, function and biology of native valves and the pathobiology, biomaterials and biomedical engineering, and the clinical management of valvular heart disease have occurred over the past several decades. This communication reviews contemporary considerations relative to the pathology of valvular heart disease, including (1) clinical significance and epidemiology of valvular heart disease; (2) functional and dynamic valvular macro-, micro- and ultrastructure; (3) causes, morphology and mechanisms of human valvular heart disease; and (4) pathologic considerations in valve replacement, repair and, potentially, regeneration of the heart valves.
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Affiliation(s)
- Frederick J Schoen
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA.
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