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Vogl B, Sularz A, Ahn S, Gadhave R, Lilly S, Thourani V, Lindman B, Alkhouli M, Hatoum H. Analysis of Energy and Pressure in the Sinus with Different Blood Pressures after Bioprosthetic Aortic Valve Replacement. Ann Biomed Eng 2024:10.1007/s10439-024-03587-w. [PMID: 39103737 DOI: 10.1007/s10439-024-03587-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 07/11/2024] [Indexed: 08/07/2024]
Abstract
PURPOSE To investigate the effect of changing systolic and diastolic blood pressures (SBP and DBP, respectively) on sinus flow and valvular and epicardial coronary flow dynamics after TAVR and SAVR. METHODS SAPIEN 3 and Magna valves were deployed in an idealized aortic root model as part of a pulse duplicating left heart flow loop simulator. Different combinations of SBP and DBP were applied to the test setup and the resulting change in total coronary flow from baseline (120/60 mmHg), effective orifice area (EOA), and left ventricular (LV) workload, with each combination, was assessed. In addition, particle image velocimetry was used to assess the Laplacian of pressure (∇ 2 P ) in the sinus, coronary and main flow velocities, the energy dissipation rate (EDR) in the sinus and the LV workload. RESULTS This study shows that under an elevated SBP, there is an increase in the total coronary flow, EOA, LV workload, peak velocities downstream of the valve,∇ 2 P , and EDR. With an elevated DBP, there was an increase in the total coronary flow and∇ 2 P . However, EOA and LV workload decreased with an increase in DBP, and EDR increased with a decrease in DBP. CONCLUSIONS Blood pressure alters the hemodynamics in the sinus and downstream flow following aortic valve replacement, potentially influencing outcomes in some patients.
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Affiliation(s)
- Brennan Vogl
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA
| | - Agata Sularz
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Sunyoung Ahn
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA
| | - Rajat Gadhave
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA
| | - Scott Lilly
- Department of Cardiovascular Medicine, The Ohio State University, Columbus, OH, USA
| | - Vinod Thourani
- Department of Cardiovascular Surgery, Piedmont Heart Institute, Marcus Valve Center, Atlanta, GA, USA
| | - Brian Lindman
- Division of Cardiovascular Medicine, Structural Heart and Valve Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Mohamad Alkhouli
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Hoda Hatoum
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA.
- Health Research Institute, Center of Biocomputing and Digital Health and Institute of Computing and Cybersystems, Michigan Technological University, Houghton, MI, USA.
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2
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Iop L. Toward the Effective Bioengineering of a Pathological Tissue for Cardiovascular Disease Modeling: Old Strategies and New Frontiers for Prevention, Diagnosis, and Therapy. Front Cardiovasc Med 2021; 7:591583. [PMID: 33748193 PMCID: PMC7969521 DOI: 10.3389/fcvm.2020.591583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/08/2020] [Indexed: 12/18/2022] Open
Abstract
Cardiovascular diseases (CVDs) still represent the primary cause of mortality worldwide. Preclinical modeling by recapitulating human pathophysiology is fundamental to advance the comprehension of these diseases and propose effective strategies for their prevention, diagnosis, and treatment. In silico, in vivo, and in vitro models have been applied to dissect many cardiovascular pathologies. Computational and bioinformatic simulations allow developing algorithmic disease models considering all known variables and severity degrees of disease. In vivo studies based on small or large animals have a long tradition and largely contribute to the current treatment and management of CVDs. In vitro investigation with two-dimensional cell culture demonstrates its suitability to analyze the behavior of single, diseased cellular types. The introduction of induced pluripotent stem cell technology and the application of bioengineering principles raised the bar toward in vitro three-dimensional modeling by enabling the development of pathological tissue equivalents. This review article intends to describe the advantages and disadvantages of past and present modeling approaches applied to provide insights on some of the most relevant congenital and acquired CVDs, such as rhythm disturbances, bicuspid aortic valve, cardiac infections and autoimmunity, cardiovascular fibrosis, atherosclerosis, and calcific aortic valve stenosis.
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Affiliation(s)
- Laura Iop
- Department of Cardiac Thoracic Vascular Sciences, and Public Health, University of Padua Medical School, Padua, Italy
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Zabirnyk A, Perez MDM, Blasco M, Stensløkken KO, Ferrer MD, Salcedo C, Vaage J. A Novel Ex Vivo Model of Aortic Valve Calcification. A Preliminary Report. Front Pharmacol 2020; 11:568764. [PMID: 33390945 PMCID: PMC7773652 DOI: 10.3389/fphar.2020.568764] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 11/16/2020] [Indexed: 12/27/2022] Open
Abstract
Background: No pharmacological treatment exists to prevent or stop the calcification process of aortic valves causing aortic stenosis. The aim of this study was to develop a robust model of induced calcification in whole aortic valve leaflets which could be suitable for studies of the basic mechanisms and for testing potentially inhibitory drugs. Methods: Pig hearts were obtained from a commercial abattoir. The aortic valve leaflets were dissected free and randomized between experimental groups. Whole leaflets were cultured in individual wells. Two growth media were used for cultivation: standard growth medium and an antimyofibroblastic growth medium. The latter was employed to inhibit contraction of the leaflet into a ball-like structure. Calcification was induced in the growth medium by supplementation with an osteogenic medium. Leaflets were cultivated for four weeks and medium was changed every third day. To block calcification, the inhibitor SNF472 (a formulation of the hexasodium salt of myo-inositol hexaphosphate hexasodium salt) was used at concentrations between 1 and 100 µM. After cultivation for four weeks the leaflets were snap frozen in liquid nitrogen and kept at −80 °C until blind assessment of the calcium amount in leaflets by inductively coupled plasma optical emission spectroscopy. For statistical analysis, a Kruskal–Wallis test with Dunn’s post-test was applied. Results: Osteodifferentiation with calcium accumulation was in principle absent when standard medium was used. However, when the antimyofibroblastic medium was used, a strong calcium accumulation was induced (p = 0.006 compared to controls), and this was blocked in a dose-dependent manner by the calcification inhibitor SNF472 (p = 0.008), with an EC50 of 3.3 µM. Conclusion: A model of experimentally induced calcification in cultured whole leaflets from porcine aortic valves was developed. This model can be useful for studying the basic mechanisms of valve calcification and to test pharmacological approaches to inhibit calcification.
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Affiliation(s)
- Arsenii Zabirnyk
- Division of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Research & Development, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway
| | | | - Marc Blasco
- Sanifit Therapeutics, Palma de Mallorca, Spain
| | - Kåre-Olav Stensløkken
- Division of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | | | | | - Jarle Vaage
- Division of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Research & Development, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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4
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Biomechanical Cues Direct Valvulogenesis. J Cardiovasc Dev Dis 2020; 7:jcdd7020018. [PMID: 32438610 PMCID: PMC7345189 DOI: 10.3390/jcdd7020018] [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: 04/01/2020] [Revised: 04/27/2020] [Accepted: 05/12/2020] [Indexed: 12/30/2022] Open
Abstract
The vertebrate embryonic heart initially forms with two chambers, a ventricle and an atrium, separated by the atrioventricular junction. Localized genetic and biomechanical information guides the development of valves, which function to ensure unidirectional blood flow. If the valve development process goes awry, pathology associated with congenital valve defects can ensue. Congenital valve defects (CVD) are estimated to affect 1–2% of the population and can often require a lifetime of treatment. Despite significant clinical interest, molecular genetic mechanisms that direct valve development remain incompletely elucidated. Cells in the developing valve must contend with a dynamic hemodynamic environment. A growing body of research supports the idea that cells in the valve are highly sensitive to biomechanical forces, which cue changes in gene expression required for normal development or for maintenance of the adult valve. This review will focus on mechanotransductive pathways involved in valve development across model species. We highlight current knowledge regarding how cells sense physical forces associated with blood flow and pressure in the forming heart, and summarize how these changes are transduced into genetic and developmental responses. Lastly, we provide perspectives on how altered biomechanical cues may lead to CVD pathogenesis.
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5
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Quaglino D, Boraldi F, Lofaro FD. The biology of vascular calcification. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 354:261-353. [PMID: 32475476 DOI: 10.1016/bs.ircmb.2020.02.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Vascular calcification (VC), characterized by different mineral deposits (i.e., carbonate apatite, whitlockite and hydroxyapatite) accumulating in blood vessels and valves, represents a relevant pathological process for the aging population and a life-threatening complication in acquired and in genetic diseases. Similarly to bone remodeling, VC is an actively regulated process in which many cells and molecules play a pivotal role. This review aims at: (i) describing the role of resident and circulating cells, of the extracellular environment and of positive and negative factors in driving the mineralization process; (ii) detailing the types of VC (i.e., intimal, medial and cardiac valve calcification); (iii) analyzing rare genetic diseases underlining the importance of altered pyrophosphate-dependent regulatory mechanisms; (iv) providing therapeutic options and perspectives.
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Affiliation(s)
- Daniela Quaglino
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy.
| | - Federica Boraldi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
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Vashistha R, Kumar P, Dangi AK, Sharma N, Chhabra D, Shukla P. Quest for cardiovascular interventions: precise modeling and 3D printing of heart valves. J Biol Eng 2019; 13:12. [PMID: 30774709 PMCID: PMC6366048 DOI: 10.1186/s13036-018-0132-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 12/11/2018] [Indexed: 12/12/2022] Open
Abstract
Digitalization of health care practices is substantially manifesting itself as an effective tool to diagnose and rectify complex cardiovascular abnormalities. For cardiovascular abnormalities, precise non-invasive imaging interventions are being used to develop patient specific diagnosis and surgical planning. Concurrently, pre surgical 3D simulation and computational modeling are aiding in the effective surgery and understanding of valve biomechanics, respectively. Consequently, 3D printing of patient specific valves that can mimic the original one will become an effective outbreak for valvular problems. Printing of these patient-specific tissues or organ components is becoming a viable option owing to the advances in biomaterials and additive manufacturing techniques. These additive manufacturing techniques are receiving a full-fledged support from burgeoning field of computational fluid dynamics, digital image processing, artificial intelligence, and continuum mechanics during their optimization and implementation. Further, studies at cellular and molecular biomechanics have enriched our understanding of biomechanical factors resulting in valvular heart diseases. Hence, the knowledge generated can guide us during the design and synthesis of biomaterials to develop superior extra cellular matrix, mimicking materials that can be used as a bioink for 3D printing of organs and tissues. With this notion, we have reviewed current opportunities and challenges in the diagnosis and treatment of heart valve abnormalities through patient-specific valve design via tissue engineering and 3D bioprinting. These valves can replace diseased valves by preserving homogeneity and individuality of the patients.
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Affiliation(s)
- Rajat Vashistha
- Optimization and Mechatronics Laboratory, Department of Mechanical Engineering, University Institute of Engineering and Technology, Maharshi Dayanand University, Rohtak, Haryana India
| | - Prasoon Kumar
- Department of Medical Devices, National Institute of Pharmaceutical Education and Research Ahmadabad, Gandhinagar, Gujarat 382355 India
| | | | - Naveen Sharma
- Department of Cardiology, Shalby Hospitals, Jabalpur, India
| | - Deepak Chhabra
- Optimization and Mechatronics Laboratory, Department of Mechanical Engineering, University Institute of Engineering and Technology, Maharshi Dayanand University, Rohtak, Haryana India
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana 124001 India
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Rutkovskiy A, Malashicheva A, Sullivan G, Bogdanova M, Kostareva A, Stensløkken KO, Fiane A, Vaage J. Valve Interstitial Cells: The Key to Understanding the Pathophysiology of Heart Valve Calcification. J Am Heart Assoc 2017; 6:e006339. [PMID: 28912209 PMCID: PMC5634284 DOI: 10.1161/jaha.117.006339] [Citation(s) in RCA: 187] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Arkady Rutkovskiy
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway
- Centre for Heart Failure Research, University of Oslo, Norway
- Department of Emergency Medicine and Intensive Care, Oslo University Hospital, Oslo, Norway
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway
- ITMO University, St. Petersburg, Russia
| | - Anna Malashicheva
- Almazov National Medical Research Centre, St. Petersburg, Russia
- ITMO University, St. Petersburg, Russia
| | - Gareth Sullivan
- Division of Biochemistry, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway
- Hybrid Technology Hub-Centre of Excellence, Institute of Basic Medical Sciences, University of Oslo, Norway
- Institute of Immunology, Oslo University Hospital, Oslo, Norway
- Norwegian Center for Stem Cell Research, Oslo, Norway
| | - Maria Bogdanova
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway
| | - Anna Kostareva
- Almazov National Medical Research Centre, St. Petersburg, Russia
- ITMO University, St. Petersburg, Russia
| | - Kåre-Olav Stensløkken
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway
- Centre for Heart Failure Research, University of Oslo, Norway
| | - Arnt Fiane
- Institute of Clinical Medicine, University of Oslo, Norway
- Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
| | - Jarle Vaage
- Institute of Clinical Medicine, University of Oslo, Norway
- Department of Emergency Medicine and Intensive Care, Oslo University Hospital, Oslo, Norway
- ITMO University, St. Petersburg, Russia
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8
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Understanding the structural features of symptomatic calcific aortic valve stenosis: A broad-spectrum clinico-pathologic study in 236 consecutive surgical cases. Int J Cardiol 2016; 228:364-374. [PMID: 27866029 DOI: 10.1016/j.ijcard.2016.11.180] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/06/2016] [Indexed: 11/20/2022]
Abstract
BACKGROUND With age, aortic valve cusps undergo varying degrees of sclerosis which, sometimes, can progress to calcific aortic valve stenosis (AVS). To perform a retrospective clinico-pathologic investigation in patients with calcific AVS. METHODS We characterized and graded the structural remodeling in 236 aortic valves (200 tricuspid and 36 bicuspid) from patients with calcific AVS (148 males; average 72years); possible relationships between general/clinical/echocardiographic characteristics and the histopathologic changes were explored. Twenty autopsy aortic valves served as controls. In 40 cases, we also tested the immunohistochemical expression of metalloproteinases and cytokines, and characterized the inflammatory infiltrate. In 5 cases, we cultured cusp stem cells and explored their potential to differentiate into osteoblasts/adipocytes. RESULTS AVS cusps showed structural remodeling as severe fibrosis (100%), calcific nodules (100%), neoangiogenesis (81%), inflammation (71%), bone metaplasia with or without hematopoiesis (6% and 53%, respectively), adipose metaplasia (16%), and cartilaginous metaplasia (7%). At multivariate analysis, AVS degree and interventricular septum thickness were the only predictors of remodeling (barring inflammation). All the tested metalloproteinases (except MMP-13) and cytokines were expressed in AVS cusps. Inflammation mainly consisted of B and T lymphocytes (CD4+/CD8+ cell ratio 3:1) and plasma cells. AVS changes were mostly different from typical atherosclerosis. Cultured mesenchymal cusp stem cells could differentiate into osteoblasts/adipocytes. CONCLUSIONS Structural remodeling in AVS is peculiar and considerable, and is related to the severity of the disease. However, the different newly formed tissues-where "valvular interstitial cells" play a key role-and their well-known slow turnover suggest a reverse structural remodeling improbable.
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9
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Tsang HG, Rashdan NA, Whitelaw CBA, Corcoran BM, Summers KM, MacRae VE. Large animal models of cardiovascular disease. Cell Biochem Funct 2016; 34:113-32. [PMID: 26914991 PMCID: PMC4834612 DOI: 10.1002/cbf.3173] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 01/26/2016] [Accepted: 01/27/2016] [Indexed: 12/12/2022]
Abstract
The human cardiovascular system is a complex arrangement of specialized structures with distinct functions. The molecular landscape, including the genome, transcriptome and proteome, is pivotal to the biological complexity of both normal and abnormal mammalian processes. Despite our advancing knowledge and understanding of cardiovascular disease (CVD) through the principal use of rodent models, this continues to be an increasing issue in today's world. For instance, as the ageing population increases, so does the incidence of heart valve dysfunction. This may be because of changes in molecular composition and structure of the extracellular matrix, or from the pathological process of vascular calcification in which bone-formation related factors cause ectopic mineralization. However, significant differences between mice and men exist in terms of cardiovascular anatomy, physiology and pathology. In contrast, large animal models can show considerably greater similarity to humans. Furthermore, precise and efficient genome editing techniques enable the generation of tailored models for translational research. These novel systems provide a huge potential for large animal models to investigate the regulatory factors and molecular pathways that contribute to CVD in vivo. In turn, this will help bridge the gap between basic science and clinical applications by facilitating the refinement of therapies for cardiovascular disease.
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Affiliation(s)
- H G Tsang
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, SCT, UK
| | - N A Rashdan
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, SCT, UK
| | - C B A Whitelaw
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, SCT, UK
| | - B M Corcoran
- Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, SCT, UK
| | - K M Summers
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, SCT, UK
| | - V E MacRae
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, SCT, UK
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10
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MacGrogan D, Luxán G, Driessen-Mol A, Bouten C, Baaijens F, de la Pompa JL. How to make a heart valve: from embryonic development to bioengineering of living valve substitutes. Cold Spring Harb Perspect Med 2014; 4:a013912. [PMID: 25368013 DOI: 10.1101/cshperspect.a013912] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Cardiac valve disease is a significant cause of ill health and death worldwide, and valve replacement remains one of the most common cardiac interventions in high-income economies. Despite major advances in surgical treatment, long-term therapy remains inadequate because none of the current valve substitutes have the potential for remodeling, regeneration, and growth of native structures. Valve development is coordinated by a complex interplay of signaling pathways and environmental cues that cause disease when perturbed. Cardiac valves develop from endocardial cushions that become populated by valve precursor mesenchyme formed by an epithelial-mesenchymal transition (EMT). The mesenchymal precursors, subsequently, undergo directed growth, characterized by cellular compartmentalization and layering of a structured extracellular matrix (ECM). Knowledge gained from research into the development of cardiac valves is driving exploration into valve biomechanics and tissue engineering directed at creating novel valve substitutes endowed with native form and function.
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Affiliation(s)
- Donal MacGrogan
- Program of Cardiovascular Developmental Biology, Department of Cardiovascular Development and Repair, Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Guillermo Luxán
- Program of Cardiovascular Developmental Biology, Department of Cardiovascular Development and Repair, Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Anita Driessen-Mol
- Biomedical Engineering/Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Carlijn Bouten
- Biomedical Engineering/Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Frank Baaijens
- Biomedical Engineering/Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - José Luis de la Pompa
- Program of Cardiovascular Developmental Biology, Department of Cardiovascular Development and Repair, Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
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11
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Defining the role of fluid shear stress in the expression of early signaling markers for calcific aortic valve disease. PLoS One 2013; 8:e84433. [PMID: 24376809 PMCID: PMC3871675 DOI: 10.1371/journal.pone.0084433] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/22/2013] [Indexed: 12/14/2022] Open
Abstract
Calcific aortic valve disease (CAVD) is an active process presumably triggered by interplays between cardiovascular risk factors, molecular signaling networks and hemodynamic cues. While earlier studies demonstrated that alterations in fluid shear stress (FSS) on the fibrosa could trigger inflammation, the mechanisms of CAVD pathogenesis secondary to side-specific FSS abnormalities are poorly understood. This knowledge could be critical to the elucidation of key CAVD risk factors such as congenital valve defects, aging and hypertension, which are known to generate FSS disturbances. The objective of this study was to characterize ex vivo the contribution of isolated and combined abnormalities in FSS magnitude and frequency to early valvular pathogenesis. The ventricularis and fibrosa of porcine aortic valve leaflets were exposed simultaneously to different combinations of sub-physiologic/physiologic/supra-physiologic levels of FSS magnitude and frequency for 24, 48 and 72 hours in a double cone-and-plate device. Endothelial activation and paracrine signaling were investigated by measuring cell-adhesion molecule (ICAM-1, VCAM-1) and cytokine (BMP-4, TGF-β1) expressions, respectively. Extracellular matrix (ECM) degradation was characterized by measuring the expression and activity of the proteases MMP-2, MMP-9, cathepsin L and cathepsin S. The effect of the FSS treatment yielding the most significant pathological response was examined over a 72-hour period to characterize the time-dependence of FSS mechano-transduction. While cytokine expression was stimulated under elevated FSS magnitude at normal frequency, ECM degradation was stimulated under both elevated FSS magnitude at normal frequency and physiologic FSS magnitude at abnormal frequency. In contrast, combined FSS magnitude and frequency abnormalities essentially maintained valvular homeostasis. The pathological response under supra-physiologic FSS magnitude peaked at 48 hours but was then maintained until the 72-hour time point. This study confirms the sensitivity of valve leaflets to both FSS magnitude and frequency and suggests the ability of supra-physiologic FSS levels or abnormal FSS frequencies to initiate CAVD mechanisms.
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12
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Arjunon S, Rathan S, Jo H, Yoganathan AP. Aortic valve: mechanical environment and mechanobiology. Ann Biomed Eng 2013; 41:1331-46. [PMID: 23515935 DOI: 10.1007/s10439-013-0785-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 03/02/2013] [Indexed: 01/11/2023]
Abstract
The aortic valve (AV) experiences a complex mechanical environment, which includes tension, flexure, pressure, and shear stress forces due to blood flow during each cardiac cycle. This mechanical environment regulates AV tissue structure by constantly renewing and remodeling the phenotype. In vitro, ex vivo and in vivo studies have shown that pathological states such as hypertension and congenital defect like bicuspid AV (BAV) can potentially alter the AV's mechanical environment, triggering a cascade of remodeling, inflammation, and calcification activities in AV tissue. Alteration in mechanical environment is first sensed by the endothelium, which in turn induces changes in the extracellular matrix, and triggers cell differentiation and activation. However, the molecular mechanism of this process is not understood very well. Understanding these mechanisms is critical for advancing the development of effective medical based therapies. Recently, there have been some interesting studies on characterizing the hemodynamics associated with AV, especially in pathologies like BAV, using different experimental and numerical methods. Here, we review the current knowledge of the local AV mechanical environment and its effect on valve biology, focusing on in vitro and ex vivo approaches.
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Affiliation(s)
- Sivakkumar Arjunon
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Room 2119 U. A. Whitaker Building, 313 Ferst Drive, Atlanta, GA 30332-0535, USA
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13
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Masoumi N, Jean A, Zugates JT, Johnson KL, Engelmayr GC. Laser microfabricated poly(glycerol sebacate) scaffolds for heart valve tissue engineering. J Biomed Mater Res A 2012; 101:104-14. [PMID: 22826211 DOI: 10.1002/jbm.a.34305] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 05/01/2012] [Accepted: 05/22/2012] [Indexed: 02/04/2023]
Abstract
Microfabricated poly(glycerol sebacate) (PGS) scaffolds may be applicable to tissue engineering heart valve leaflets by virtue of their controllable microstructure, stiffness, and elasticity. In this study, PGS scaffolds were computationally designed and microfabricated by laser ablation to match the anisotropy and peak tangent moduli of native bovine aortic heart valve leaflets. Finite element simulations predicted PGS curing conditions, scaffold pore shape, and strut width capable of matching the scaffold effective stiffnesses to the leaflet peak tangent moduli. On the basis of simulation predicted effective stiffnesses of 1.041 and 0.208 MPa for the scaffold preferred (PD) and orthogonal, cross-preferred (XD) material directions, scaffolds with diamond-shaped pores were microfabricated by laser ablation of PGS cured 12 h at 160°C. Effective stiffnesses measured for the scaffold PD (0.83 ± 0.13 MPa) and XD (0.21 ± 0.03 MPa) were similar to both predicted values and peak tangent moduli measured for bovine aortic valve leaflets in the circumferential (1.00 ± 0.16 MPa) and radial (0.26 ± 0.03 MPa) directions. Scaffolds cultivated with fibroblasts for 3 weeks accumulated collagen (736 ± 193 μg/g wet weight) and DNA (17 ± 4 μg/g wet weight). This study provides a basis for the computational design of biomimetic microfabricated PGS scaffolds for tissue-engineered heart valves.
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Affiliation(s)
- Nafiseh Masoumi
- Department of Bioengineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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