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Gumpangseth T, Komutrattananont P, Palee P, Lekawanvijit S, Kanchai C, Prasitwattanaseree S, Mahakkanukrauh P. Collagen and elastic fibers assessment of the human heart valves for age estimation in Thais using image analysis. Forensic Sci Med Pathol 2024:10.1007/s12024-023-00775-3. [PMID: 38634992 DOI: 10.1007/s12024-023-00775-3] [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] [Accepted: 12/27/2023] [Indexed: 04/19/2024]
Abstract
The study investigated the relationship between the histological compositions of the tricuspid, pulmonary, mitral, and aortic valves, and age. All 85 fresh human hearts were obtained with an age range between 20 and 90 years. The central area of the valves was conducted to analyze the density of collagen and elastic fibers by using an image analysis program. Neural network function in MATLAB was used for classification data and accuracy test of the age predictive model. Overall, a gradual increase in the density of collagen and elastic fibers was demonstrated with age in all valve types. The pulmonary valve cusps had the least density of collagen and elastic contents, whereas the most dense of collagen was found in the mitral leaflets. A similarity was noted for the elastic fibers in the tricuspid, mitral, and aortic valves. The highest correlation between the collagen (r = 0.629) and elastic fibers (r = 0.713) and age was found in the noncoronary cusp of the aortic valve. The established predictive equations using collagen and elastic fibers in the noncoronary cusp provided the standard error of ± 14.0 and 12.5 years, respectively. A 60.9% of accuracy was found in all age groups using collagen, while accuracy in elastic fibers showed 70.0% in the classification process using the neural networks. The current study provided additional data regarding age-associated changes of collagen and elastic fibers in the human heart valves in Thais and the benefits and application in age forensic identification.
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Affiliation(s)
- Treerat Gumpangseth
- Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Excellence Center in Osteology Research and Training Center (ORTC), Chiang Mai University, Chiang Mai, 50200, Thailand
| | | | - Patison Palee
- College of Arts Media and Technology, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Suree Lekawanvijit
- Department of Pathology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Chaturong Kanchai
- Department of Forensic Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Sukon Prasitwattanaseree
- Department of Statistics, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Pasuk Mahakkanukrauh
- Excellence Center in Osteology Research and Training Center (ORTC), Chiang Mai University, Chiang Mai, 50200, Thailand.
- Department of Anatomy, Faculty of Medicine and Research Cluster in Osteology Research and Training Center (ORTC), Chiang Mai University, Chiang Mai, 50200, Thailand.
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2
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Ahmad F, Soe S, Albon J, Errington R, Theobald P. Quantifying the microstructural and biomechanical changes in the porcine ventricles during growth and remodelling. Acta Biomater 2023; 171:166-192. [PMID: 37797709 DOI: 10.1016/j.actbio.2023.09.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 09/19/2023] [Accepted: 09/26/2023] [Indexed: 10/07/2023]
Abstract
Cardiac tissue growth and remodelling (G & R) occur in response to the changing physiological demands of the heart after birth. The early shift to pulmonary circulation produces an immediate increase in ventricular workload, causing microstructural and biomechanical changes that serve to maintain overall physiological homoeostasis. Such cardiac G & R continues throughout life. Quantifying the tissue's mechanical and microstructural changes because of G & R is of increasing interest, dovetailing with the emerging fields of personalised and precision solutions. This study aimed to determine equibiaxial, and non-equibiaxial extension, stress-relaxation, and the underlying microstructure of the passive porcine ventricles tissue at four time points spanning from neonatal to adulthood. The three-dimensional microstructure was investigated via two-photon excited fluorescence and second-harmonic generation microscopy on optically cleared tissues, describing the 3D orientation, rotation and dispersion of the cardiomyocytes and collagen fibrils. The results revealed that during biomechanical testing, myocardial ventricular tissue possessed non-linear, anisotropic, and viscoelastic behaviour. An increase in stiffness and viscoelasticity was noted for the left and right ventricular free walls from neonatal to adulthood. Microstructural analyses revealed concomitant increases in cardiomyocyte rotation and dispersion. This study provides baseline data, describing the biomechanical and microstructural changes in the left and right ventricular myocardial tissue during G & R, which should prove valuable to researchers in developing age-specific, constitutive models for more accurate computational simulations. STATEMENT OF SIGNIFICANCE: There is a dearth of experimental data describing the growth and remodelling of left and right ventricular tissue. The published literature is fragmented, with data reported via different experimental techniques using tissues harvested from a variety of animals, with different gender and ages. This prevents developing a continuum of data spanning birth to death, so limiting the potential that can be leveraged to aid computational modelling and simulations. In this study, equibiaxial, non-equibiaxial, and stress-relaxation data are presented, describing directional-dependent material responses. The biomechanical data is consolidated with equivalent microstructural data, an important element for the development of future material models. Combined, these data describe microstructural and biomechanical changes in the ventricles, spanning G &R from neonatal to adulthood.
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Affiliation(s)
- Faizan Ahmad
- School of Engineering, Cardiff University, UK; School of Health Sciences, Birmingham City University, UK.
| | - Shwe Soe
- FET - Engineering, Design and Mathematics, University of West of England, UK
| | - Julie Albon
- School of Optometry and Vision Sciences, Cardiff University, UK; Viva Scientia Bioimaging Laboratories, Cardiff University, UK
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3
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Tang Q, McNair AJ, Phadwal K, Macrae VE, Corcoran BM. The Role of Transforming Growth Factor-β Signaling in Myxomatous Mitral Valve Degeneration. Front Cardiovasc Med 2022; 9:872288. [PMID: 35656405 PMCID: PMC9152029 DOI: 10.3389/fcvm.2022.872288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/12/2022] [Indexed: 02/03/2023] Open
Abstract
Mitral valve prolapse (MVP) due to myxomatous degeneration is one of the most important chronic degenerative cardiovascular diseases in people and dogs. It is a common cause of heart failure leading to significant morbidity and mortality in both species. Human MVP is usually classified into primary or non-syndromic, including Barlow’s Disease (BD), fibro-elastic deficiency (FED) and Filamin-A mutation, and secondary or syndromic forms (typically familial), such as Marfan syndrome (MFS), Ehlers-Danlos syndrome, and Loeys–Dietz syndrome. Despite different etiologies the diseased valves share pathological features consistent with myxomatous degeneration. To reflect this common pathology the condition is often called myxomatous mitral valve degeneration (disease) (MMVD) and this term is universally used to describe the analogous condition in the dog. MMVD in both species is characterized by leaflet thickening and deformity, disorganized extracellular matrix, increased transformation of the quiescent valve interstitial cell (qVICs) to an activated state (aVICs), also known as activated myofibroblasts. Significant alterations in these cellular activities contribute to the initiation and progression of MMVD due to the increased expression of transforming growth factor-β (TGF-β) superfamily cytokines and the dysregulation of the TGF-β signaling pathways. Further understanding the molecular mechanisms of MMVD is needed to identify pharmacological manipulation strategies of the signaling pathway that might regulate VIC differentiation and so control the disease onset and development. This review briefly summarizes current understanding of the histopathology, cellular activities, molecular mechanisms and pathogenesis of MMVD in dogs and humans, and in more detail reviews the evidence for the role of TGF-β.
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Affiliation(s)
- Qiyu Tang
- The Roslin Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew J. McNair
- The Roslin Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Kanchan Phadwal
- The Roslin Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Vicky E. Macrae
- The Roslin Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Brendan M. Corcoran
- The Roslin Institute, The University of Edinburgh, Edinburgh, United Kingdom
- Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Edinburgh, United Kingdom
- *Correspondence: Brendan M. Corcoran,
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4
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Mechanosensing dysregulation in the fibroblast: A hallmark of the aging heart. Ageing Res Rev 2020; 63:101150. [PMID: 32846223 DOI: 10.1016/j.arr.2020.101150] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/03/2020] [Accepted: 08/14/2020] [Indexed: 12/16/2022]
Abstract
The myofibroblast is a specialized fibroblast that expresses α-smooth muscle actin (α-SMA) and participates in wound contraction and fibrosis. The fibroblast to myofibroblast transition depends on chemical and mechanical signals. A fibroblast senses the changes in the environment (extracellular matrix (ECM)) and transduces these changes to the cytoskeleton and the nucleus, resulting in activation or inhibition of α-SMA transcription in a process called mechanosensing. A stiff matrix greatly facilitates the transition from fibroblast to myofibroblast, and although the aging heart is much stiffer than the young one, the aging fibroblast has difficulties in transitioning into the contractile phenotype. This suggests that the events occurring downstream of the matrix, such as activation or changes in expression levels of various proteins participating in mechanotransduction can negatively alter the ability of the aging fibroblast to become a myofibroblast. In this review, we will discuss in detail the changes in ECM, receptors (integrin or non-integrin), focal adhesions, cytoskeleton, and transcription factors involved in mechanosensing that occur with aging.
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5
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Gumpangseth T, Lekawanvijit S, Mahakkanukrauh P. Histological assessment of the human heart valves and its relationship with age. Anat Cell Biol 2020; 53:261-271. [PMID: 32727956 PMCID: PMC7527117 DOI: 10.5115/acb.20.093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/27/2020] [Accepted: 06/01/2020] [Indexed: 11/27/2022] Open
Abstract
The human heart valves are complex anatomical structures consisting of leaflets with many supporting structures. With advancing age, the microstructure of the components of the valves can change. Knowledge and understanding of the anatomical relationships between the different components of the heart valve structures and their relationship with age is crucial for the development and progression of treatment of valvular disease. The purpose of this study was to determine histological changes of the components of the heart valves and their relationship with age. Fifty hearts taken from cadavers were included to examine the histology of the tricuspid, mitral, pulmonary, and aortic valves. All specimens were stained with Elastic Van Gieson, and picrosirius red to enable the evaluation of elastic and collagen fibers, respectively. There was a gradual increase in elastic and collagen fibers with advancing age, particularly over 40 years, in all valve types. In the case of tricuspid and mitral valves increases in collagen and elastic fibers were observed starting in the fifth decade. Elastic fiber fragmentation was observed in specimens over 50 years. In the case of the pulmonary and the aortic valves, collagen fibers were denser and more irregular in the sixth to seventh decades when compared to younger ages while elastic fibers were significantly increased in the sixth decade. In addition, an increase in fat deposition had an association with aging. These findings provide additional basic knowledge in age-related morphological changes of the heart valves and will increase understanding concerning valvular heart diseases and treatment options.
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Affiliation(s)
- Treerat Gumpangseth
- PhD Degree Program in Anatomy, Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Suree Lekawanvijit
- Department of Pathology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Pasuk Mahakkanukrauh
- Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Excellence in Osteology Research and Training Center (ORTC), Chiang Mai University, Chiang Mai, Thailand
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6
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Fletcher AJ, Singh T, Syed MBJ, Dweck MR. Imaging aortic valve calcification: significance, approach and implications. Clin Radiol 2020; 76:15-26. [PMID: 32446601 DOI: 10.1016/j.crad.2020.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 04/16/2020] [Indexed: 12/18/2022]
Abstract
Aortic stenosis is the most prevalent valvular heart disease worldwide, and rates are increasing with the growing and more elderly population. Although the precise mechanisms that underpin aortic valve stenosis are incompletely understood, pathological valvular calcification has emerged as a key instigator in mediating the biomechanical stiffening that can lead to symptoms, the need for aortic valve replacement, and death if left untreated. Here, we review the currently understood processes leading to aortic valve calcification, summarise the contemporary imaging assessments of valve calcification, and highlight how these might improve patient care and accelerate our pathological understanding and the development of an effective medical therapy.
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Affiliation(s)
- A J Fletcher
- University of Edinburgh Centre for Cardiovascular Science, Chancellor's Building, Royal Infirmary of Edinburgh, UK
| | - T Singh
- University of Edinburgh Centre for Cardiovascular Science, Chancellor's Building, Royal Infirmary of Edinburgh, UK
| | - M B J Syed
- University of Edinburgh Centre for Cardiovascular Science, Chancellor's Building, Royal Infirmary of Edinburgh, UK
| | - M R Dweck
- University of Edinburgh Centre for Cardiovascular Science, Chancellor's Building, Royal Infirmary of Edinburgh, UK.
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7
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Markby GR, Macrae VE, Summers KM, Corcoran BM. Disease Severity-Associated Gene Expression in Canine Myxomatous Mitral Valve Disease Is Dominated by TGFβ Signaling. Front Genet 2020; 11:372. [PMID: 32395121 PMCID: PMC7197751 DOI: 10.3389/fgene.2020.00372] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/26/2020] [Indexed: 12/21/2022] Open
Abstract
Myxomatous mitral valve disease (MMVD) is the most common acquired canine cardiovascular disease and shares many similarities with human mitral valvulopathies. While transcriptomic datasets are available for the end-stage disease in both species, there is no information on how gene expression changes as the disease progresses, such that it cannot be stated with certainty if the changes seen in end-stage disease are casual or consequential. In contrast to humans, the disease in dogs can be more readily examined as it progresses, and this allows an opportunity for insight into disease pathogenesis relevant to both species. The aim of this study was to identify changes in valve gene expression as canine MMVD advances over an entire life-time, from normal (grade 0) to severely affected (grade 4), and differences in gene expression comparing normal and disease areas of the same valve. Transcriptomic profiling identified 1002 differentially expressed genes (DEGs) across all four disease grades when compared with normal valves with the greatest number of DEGs in grade 3 (673) and grade 4 (507). DEGs were associated with a large number of gene families, including genes encoding cytoskeletal filaments, peptidases, extra-cellular matrix (ECM) proteins, chemokines and integrins. Gene enrichment analysis identified significant grade-dependent changes in gene clustering, with clusters trending both up and down as disease progressed. Significant grade-dependent changes in hallmark disease gene expression intensity were identified, including ACTA2, HTR2B, MMP12, and CDKN2A. Gene Ontology terms were dominated by terms for ECM and inflammation with TGFβ1, TNF, IFGN identified as the top up-stream regulators in both whole and dissected diseased valve samples. These data show that while disease progression in MMVD is associated with increasing numbers of DEGs, TGFβ appears to be the dominant signaling pathway controlling pathogenesis irrespective of disease severity.
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Affiliation(s)
- Greg R Markby
- The Roslin Institute, University of Edinburgh, Scotland, United Kingdom
| | - Vicky E Macrae
- The Roslin Institute, University of Edinburgh, Scotland, United Kingdom
| | - Kim M Summers
- The Roslin Institute, University of Edinburgh, Scotland, United Kingdom
| | - Brendan M Corcoran
- The Roslin Institute, University of Edinburgh, Scotland, United Kingdom.,Royal Dick, School of Veterinary Studies, University of Edinburgh, Scotland, United Kingdom
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8
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Gumpangseth T, Mahakkanukrauh P, Das S. Gross age-related changes and diseases in human heart valves. Anat Cell Biol 2019; 52:25-33. [PMID: 30984448 PMCID: PMC6449582 DOI: 10.5115/acb.2019.52.1.25] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/13/2018] [Accepted: 09/27/2018] [Indexed: 12/18/2022] Open
Abstract
Cardiac valves are highly complex structures optimizing their function during the cardiac cycle. They open and close directed by blood flow under different pressure conditions in the dynamic environment in the heart. It is acknowledged that the aging process affects the structure and functions of the heart valves. With regard to morphometry, age-related changes of the heart valve can be found in valve circumference, thickness of the leaflet, luminal area at the sinotubular junction, valve diameter, orifice area, and leaflet size in circumferential and radial direction. In addition, there are differences between male and female hearts in some features. Moreover, there are studies the qualitative and quantitative assessment of histological compositions, echocardiography study to investigate the annular circumference and diameter in the human heart valves related with age. Studies into the detailed anatomy of the changes in heart valves with age are important and the correlation between valve morphology and age may be used as an age indicator. This study reviews the basic anatomical structure of the heart valves, age-related changes of valve morphometry, heart valve diseases, and general treatment of valvular diseases in humans. Detailed knowledge of the anatomical features of the morphology of the human heart valve is useful for any treatments of valve pathology.
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Affiliation(s)
- Treerat Gumpangseth
- Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Pasuk Mahakkanukrauh
- Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Forensic Osteology Research Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Excellence in Osteology Research and Training Center (ORTC), Chiang Mai University, Chiang Mai, Thailand
| | - Srijit Das
- Department of Anatomy, Universiti Kebangsaan Malaysia Medical Centre, Cheras, Kuala Lumpur, Malaysia
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9
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Dallard J, Labrosse MR, Sohmer B, Beller CJ, Boodhwani M. Investigation of raphe function in the bicuspid aortic valve and its influence on clinical criteria-A patient-specific finite element study. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3117. [PMID: 29905015 DOI: 10.1002/cnm.3117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/05/2018] [Indexed: 06/08/2023]
Abstract
The aortic valve is normally composed of 3 cusps. In one common lesion, 2 cusps are fused together. The conjoined area of the fused cusps is termed raphe. Occurring in 1% to 2% of the population, the bicuspid aortic valve (BAV) is the most common congenital cardiac malformation. The majority of BAV patients eventually require surgery. There is a lack in the literature regarding modeling of the raphe (geometry and material properties), its role and its influence on BAV function. The present study aims to propose improvements on these aspects. Three patient-specific finite element models of BAVs were created based on 3D trans-esophageal echocardiography measurements, and assuming age-dependent material properties. The raphe was initially given the same material properties as its underlying cusps. Two levels of validation were performed; one based on the anatomical validation of the pressurized geometry in diastole (involving 7 anatomical measures), as simulated starting from the unpressurized geometry, and the other based on a functional assessment using clinical measurements in both systole and diastole (involving 16 functional measures). The pathology was successfully reproduced in the FE models of all 3 patients. To further investigate the role of the raphe, 2 additional scenarios were considered; (1) the raphe was considered as almost rigid, (2) the raphe was totally removed. The results confirmed the interpretation of the raphe as added stiffness in the fused cusp's rotation with respect to the aortic wall, as well as added support for stress distribution from the fused cusps to the aortic wall.
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Affiliation(s)
- Jérémy Dallard
- Department of Mechanical Engineering, University of Ottawa, Ottawa, Ontario, Canada
| | - Michel R Labrosse
- Department of Mechanical Engineering, University of Ottawa, Ottawa, Ontario, Canada
| | - Benjamin Sohmer
- Division of Cardiac Anesthesiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Carsten J Beller
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Munir Boodhwani
- Division of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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Growth and remodeling play opposing roles during postnatal human heart valve development. Sci Rep 2018; 8:1235. [PMID: 29352179 PMCID: PMC5775310 DOI: 10.1038/s41598-018-19777-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/03/2018] [Indexed: 01/13/2023] Open
Abstract
Tissue growth and remodeling are known to govern mechanical homeostasis in biological tissue, but their relative contributions to homeostasis remain unclear. Here, we use mechanical models, fueled by experimental findings, to demonstrate that growth and remodeling have different effects on heart valve stretch homeostasis during physiological postnatal development. Two developmental stages were considered: early-stage (from infant to adolescent) and late-stage (from adolescent to adult) development. Our models indicated that growth and remodeling play opposing roles in preserving tissue stretch and with time. During early-stage development, excessive tissue stretch was decreased by tissue growth and increased by remodeling. In contrast, during late-stage development tissue stretch was decreased by remodeling and increased by growth. Our findings contribute to an improved understanding of native heart valve adaptation throughout life, and are highly relevant for the development of tissue-engineered heart valves.
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11
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Malischewski A, Moreira R, Hurtado L, Gesché V, Schmitz-Rode T, Jockenhoevel S, Mela P. Umbilical cord as human cell source for mitral valve tissue engineering - venous vs. arterial cells. ACTA ACUST UNITED AC 2017; 62:457-466. [PMID: 28453437 DOI: 10.1515/bmt-2016-0218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 03/01/2017] [Indexed: 11/15/2022]
Abstract
Around 2% of the population in developed nations are affected by mitral valve disease and available valvular replacements are not designed for the atrioventricular position. Recently our group developed the first tissue-engineered heart valve (TEHV) specifically designed for the mitral position - the TexMi valve. The valve recapitulates the main components of the native valve, i.e. annulus, asymmetric leaflets and the crucial chordae tendineae. In the present study, we evaluated the human umbilical cord as a clinically applicable cell source for the TexMi valve. Valves produced with cells isolated from human umbilical cord veins (HUVs) and human umbilical cord arteries (HUAs) were conditioned for 21 days in custom-made bioreactors and evaluated in terms of extracellular matrix (ECM) composition and mechanical properties. In addition, static cell-laden fibrin discs were molded to investigate cell-mediated tissue contraction and differences in ECM production. HUA and HUV cells were able to deliver functional valves with a rich ECM composed mainly of collagen. Particularly noteworthy was the synthesis of elastin, which has been observed rarely in TEHV. The elastin synthesis was significantly higher in TexMi valves produced with HUV cells and therefore the HUV is considered to be the preferred cell source.
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12
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Sohmer B, Jafar R, Patel P, Chamberland MÈ, Labrosse MR, Boodhwani M. Aortic Valve Cusp Coaptation Surface Area Using 3-Dimensional Transesophageal Echocardiography Correlates with Severity of Aortic Valve Insufficiency. J Cardiothorac Vasc Anesth 2017; 32:344-351. [PMID: 29128482 DOI: 10.1053/j.jvca.2017.08.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Indexed: 12/14/2022]
Abstract
OBJECTIVE The aim of this study was to test both in humans and using finite element (FE) aortic valve (AV) models whether the coaptation surface area (CoapSA) correlates with aortic insufficiency (AI) severity due to dilated aortic roots to determine the validity and utility of 3-dimensional transesophageal echocardiographic-measured CoapSA. DESIGN Two-pronged, clinical and computational approach. SETTING Single university hospital. PARTICIPANTS The study comprised 10 patients with known AI and 98 FE simulations of increasingly dilated human aortic roots. INTERVENTIONS The CoapSA was calculated using intraoperative 3-dimensional transesophageal echocardiography data of patients with isolated AI and compared with established quantifiers of AI. In addition, the CoapSA and effective regurgitant orifice area (EROA) were determined using FE simulations. MEASUREMENTS AND MAIN RESULTS In the 10 AI patients, regurgitant fraction (RF) increased with EROA (R2 = 0.77, p = 0.0008); CoapSA decreased with RF (R2 = 0.72, p = 0.0020); CoapSA decreased with EROA (R2 = 0.71, p = 0.0021); and normalized CoapSA (CoapSA / [Ventriculo-Aortic Junction × Sinotubular Junction]) decreased with EROA (R2 = 0.60, p = 0.0088). In the 98 FE simulations, normalized CoapSA decreased with EROA (R2 = 0.50, p = 0.0001). CONCLUSIONS In both human and FE AV models, CoapSA was observed to be inversely correlated with AI severity, EROA, and RF, thereby supporting the validity and utility of 3D TEE-measured CoapSA. A clinical implication is the expectation that high values of CoapSA, measured intraoperatively after AV repairs, would correlate with better long-term outcomes of those repairs.
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Affiliation(s)
- Benjamin Sohmer
- Division of Cardiac Anesthesiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
| | - Reza Jafar
- Division of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, Ontario, Canada; Department of Mechanical Engineering, University of Ottawa, Ottawa, Ontario, Canada
| | - Prakash Patel
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA
| | - Marie-Ève Chamberland
- Division of Cardiac Anesthesiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Michel R Labrosse
- Department of Mechanical Engineering, University of Ottawa, Ottawa, Ontario, Canada
| | - Munir Boodhwani
- Division of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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13
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Markby GR, Summers KM, MacRae VE, Corcoran BM. Comparative Transcriptomic Profiling and Gene Expression for Myxomatous Mitral Valve Disease in the Dog and Human. Vet Sci 2017; 4:vetsci4030034. [PMID: 29056693 PMCID: PMC5644653 DOI: 10.3390/vetsci4030034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 06/02/2017] [Accepted: 06/06/2017] [Indexed: 12/28/2022] Open
Abstract
Myxomatous mitral valve disease is the single most important mitral valve disease in both dogs and humans. In the case of the dog it is ubiquitous, such that all aged dogs will have some evidence of the disease, and for humans it is known as Barlow's disease and affects up to 3% of the population, with an expected increase in prevalence as the population ages. Disease in the two species show many similarities and while both have the classic myxomatous degeneration only in humans is there extensive fibrosis. This dual pathology of the human disease markedly affects the valve transcriptome and the difference between the dog and human is dominated by changes in genes associated with fibrosis. This review will briefly examine the comparative valve pathology and then, in more detail, the transcriptomic profiling and gene expression reported so far for both species.
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Affiliation(s)
- Greg R Markby
- Roslin Institute, The University of Edinburgh, Easterbush Veterinary Centre, Roslin, Scotland EH25 9RG, UK.
- Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easterbush Veterinary Centre, Roslin, Scotland EH25 9RG, UK.
| | - Kim M Summers
- Roslin Institute, The University of Edinburgh, Easterbush Veterinary Centre, Roslin, Scotland EH25 9RG, UK.
- Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easterbush Veterinary Centre, Roslin, Scotland EH25 9RG, UK.
| | - Vicky E MacRae
- Roslin Institute, The University of Edinburgh, Easterbush Veterinary Centre, Roslin, Scotland EH25 9RG, UK.
- Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easterbush Veterinary Centre, Roslin, Scotland EH25 9RG, UK.
| | - Brendan M Corcoran
- Roslin Institute, The University of Edinburgh, Easterbush Veterinary Centre, Roslin, Scotland EH25 9RG, UK.
- Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easterbush Veterinary Centre, Roslin, Scotland EH25 9RG, UK.
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Myxomatous Degeneration of the Canine Mitral Valve: From Gross Changes to Molecular Events. J Comp Pathol 2017; 156:371-383. [PMID: 28408040 DOI: 10.1016/j.jcpa.2017.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/10/2017] [Accepted: 01/13/2017] [Indexed: 11/22/2022]
Abstract
Myxomatous mitral valve disease (MMVD) is the single most common acquired heart disease of the dog, but is also of emerging importance in human medicine, with some features of the disease shared between both species. There has been increased understanding of this disease in recent years, with most research aiming to elucidate the cellular and molecular events of disease pathogenesis. For gross and histological changes, much of our understanding is based on historical studies and there has been no comprehensive reappraisal of the pathology of MMVD. This paper reviews the gross, histological, ultrastructural, cellular and molecular changes in canine MMVD.
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15
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Sapp MC, Krishnamurthy VK, Puperi DS, Bhatnagar S, Fatora G, Mutyala N, Grande-Allen KJ. Differential cell-matrix responses in hypoxia-stimulated aortic versus mitral valves. J R Soc Interface 2016; 13:20160449. [PMID: 28003526 PMCID: PMC5221519 DOI: 10.1098/rsif.2016.0449] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 11/25/2016] [Indexed: 01/17/2023] Open
Abstract
Tissue oxygenation often plays a significant role in disease and is an essential design consideration for tissue engineering. Here, oxygen diffusion profiles of porcine aortic and mitral valve leaflets were determined using an oxygen diffusion chamber in conjunction with computational models. Results from these studies revealed the differences between aortic and mitral valve leaflet diffusion profiles and suggested that diffusion alone was insufficient for normal oxygen delivery in mitral valves. During fibrotic valve disease, leaflet thickening due to abnormal extracellular matrix is likely to reduce regional oxygen availability. To assess the impact of low oxygen levels on valve behaviour, whole leaflet organ cultures were created to induce leaflet hypoxia. These studies revealed a loss of layer stratification and elevated levels of hypoxia inducible factor 1-alpha in both aortic and mitral valve hypoxic groups. Mitral valves also exhibited altered expression of angiogenic factors in response to low oxygen environments when compared with normoxic groups. Hypoxia affected aortic and mitral valves differently, and mitral valves appeared to show a stenotic, rheumatic phenotype accompanied by significant cell death. These results indicate that hypoxia could be a factor in mid to late valve disease progression, especially with the reduction in chondromodulin-1 expression shown by hypoxic mitral valves.
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Affiliation(s)
- Matthew C Sapp
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | | | - Daniel S Puperi
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Saheba Bhatnagar
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Gabrielle Fatora
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Neelesh Mutyala
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
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16
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Brioschi M, Baetta R, Ghilardi S, Gianazza E, Guarino A, Parolari A, Polvani G, Tremoli E, Banfi C. Normal human mitral valve proteome: A preliminary investigation by gel-based and gel-free proteomic approaches. Electrophoresis 2016; 37:2633-2643. [PMID: 27450324 DOI: 10.1002/elps.201600081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 06/27/2016] [Accepted: 07/14/2016] [Indexed: 12/24/2022]
Abstract
The mitral valve is a highly complex structure which regulates blood flow from the left atrium to the left ventricle (LV) avoiding a significant forward gradient during diastole or regurgitation during systole. The integrity of the mitral valve is also essential for the maintenance of normal LV size, geometry, and function. Significant advances in the comprehension of the biological, functional, and mechanical behavior of the mitral valve have recently been made. However, current knowledge of protein components in the normal human mitral valve is still limited and complicated by the low cellularity of this tissue and the presence of high abundant proteins from the extracellular matrix. We employed here an integrated proteomic approach to analyse the protein composition of the normal human mitral valve and reported confident identification of 422 proteins, some of which have not been previously described in this tissue. In particular, we described the ability of pre-MS separation technique based on liquid-phase IEF and SDS-PAGE to identify the largest number of proteins. We also demonstrated that some of these proteins, e.g. αB-Crystallin, septin-11, four-and-a-half LIM domains protein 1, and dermatopontin, are synthesised by interstitial cells isolated from human mitral valves. These initial results provide a valuable basis for future studies aimed at analysing in depth the mitral valve protein composition and at investigating potential pathogenetic molecular mechanisms. Data are available via ProteomeXchange with identifier PXD004397.
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Affiliation(s)
| | | | | | | | - Anna Guarino
- Centro Cardiologico Monzino, IRCCS, Milan, Italy.,Banca Tessuti Cardiovascolari Regione Lombardia, Centro Cardiologico Monzino IRCCS Milan, Milan, Italy
| | - Alessandro Parolari
- Dipartimento di Chirurgia cardiaca, IRCCS Policlinico San Donato, Milan, Italy
| | - Gianluca Polvani
- Centro Cardiologico Monzino, IRCCS, Milan, Italy.,Università degli Studi di Milano, Dipartimento di Scienze Cliniche e di Comunità, Sezione Cardiovascolare, Milan, Italy
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17
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van Geemen D, Soares ALF, Oomen PJA, Driessen-Mol A, Janssen-van den Broek MWJT, van den Bogaerdt AJ, Bogers AJJC, Goumans MJTH, Baaijens FPT, Bouten CVC. Age-Dependent Changes in Geometry, Tissue Composition and Mechanical Properties of Fetal to Adult Cryopreserved Human Heart Valves. PLoS One 2016; 11:e0149020. [PMID: 26867221 PMCID: PMC4750936 DOI: 10.1371/journal.pone.0149020] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 01/26/2016] [Indexed: 11/18/2022] Open
Abstract
There is limited information about age-specific structural and functional properties of human heart valves, while this information is key to the development and evaluation of living valve replacements for pediatric and adolescent patients. Here, we present an extended data set of structure-function properties of cryopreserved human pulmonary and aortic heart valves, providing age-specific information for living valve replacements. Tissue composition, morphology, mechanical properties, and maturation of leaflets from 16 pairs of structurally unaffected aortic and pulmonary valves of human donors (fetal-53 years) were analyzed. Interestingly, no major differences were observed between the aortic and pulmonary valves. Valve annulus and leaflet dimensions increase throughout life. The typical three-layered leaflet structure is present before birth, but becomes more distinct with age. After birth, cell numbers decrease rapidly, while remaining cells obtain a quiescent phenotype and reside in the ventricularis and spongiosa. With age and maturation-but more pronounced in aortic valves-the matrix shows an increasing amount of collagen and collagen cross-links and a reduction in glycosaminoglycans. These matrix changes correlate with increasing leaflet stiffness with age. Our data provide a new and comprehensive overview of the changes of structure-function properties of fetal to adult human semilunar heart valves that can be used to evaluate and optimize future therapies, such as tissue engineering of heart valves. Changing hemodynamic conditions with age can explain initial changes in matrix composition and consequent mechanical properties, but cannot explain the ongoing changes in valve dimensions and matrix composition at older age.
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Affiliation(s)
- Daphne van Geemen
- Soft Tissue Biomechanics & Engineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Ana L. F. Soares
- Soft Tissue Biomechanics & Engineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Pim J. A. Oomen
- Soft Tissue Biomechanics & Engineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Anita Driessen-Mol
- Soft Tissue Biomechanics & Engineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, Netherlands
| | | | - Antoon J. van den Bogaerdt
- Heart Valve Bank Rotterdam, Department of Cardio-Thoracic Surgery, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Ad J. J. C. Bogers
- Heart Valve Bank Rotterdam, Department of Cardio-Thoracic Surgery, Erasmus University Medical Center, Rotterdam, Netherlands
- Department of Cardio-Thoracic Surgery, Erasmus University Medical Center, Rotterdam, Netherlands
| | | | - Frank P. T. Baaijens
- Soft Tissue Biomechanics & Engineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Carlijn V. C. Bouten
- Soft Tissue Biomechanics & Engineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, Netherlands
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18
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Cells and extracellular matrix interplay in cardiac valve disease: because age matters. Basic Res Cardiol 2016; 111:16. [PMID: 26830603 DOI: 10.1007/s00395-016-0534-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 12/27/2015] [Accepted: 01/19/2016] [Indexed: 12/18/2022]
Abstract
Cardiovascular aging is a physiological process affecting all components of the heart. Despite the interest and experimental effort lavished on aging of cardiac cells, increasing evidence is pointing at the pivotal role of extracellular matrix (ECM) in cardiac aging. Structural and molecular changes in ECM composition during aging are at the root of significant functional modifications at the level of cardiac valve apparatus. Indeed, calcification or myxomatous degeneration of cardiac valves and their functional impairment can all be explained in light of age-related ECM alterations and the reciprocal interplay between altered ECM and cellular elements populating the leaflet, namely valvular interstitial cells and valvular endothelial cells, is additionally affecting valve function with striking reflexes on the clinical scenario. The initial experimental findings on this argument are underlining the need for a more comprehensive understanding on the biological mechanisms underlying ECM aging and remodeling as potentially constituting a pharmacological therapeutic target or a basis to improve existing prosthetic devices and treatment options. Given the lack of systematic knowledge on this topic, this review will focus on the ECM changes that occur during aging and on their clinical translational relevance and implications in the bedside scenario.
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19
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Carthy JM, Abraham T, Meredith AJ, Boroomand S, McManus BM. Versican localizes to the nucleus in proliferating mesenchymal cells. Cardiovasc Pathol 2015; 24:368-74. [PMID: 26395512 DOI: 10.1016/j.carpath.2015.07.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 07/29/2015] [Accepted: 07/29/2015] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE Versican is a versatile and highly interactive chondroitin sulfate proteoglycan that is found in the extracellular matrix (ECM) of many tissues and is a major component of developing and developed lesions in atherosclerotic vascular disease. In this paper, we present data to indicate that versican may have important intracellular functions in addition to its better known roles in the ECM. METHODS AND RESULTS Rat aortic smooth muscle cells were fixed and immunostained for versican and images of fluorescently labeled cells were obtained by confocal microscopy. Intracellular versican was detected in the nucleus and cytosol of vascular smooth muscle cells. The use of a synthetic neutralizing peptide eliminated versican immunostaining, demonstrating the specificity of the antibody used in this study. Western blot of pure nuclear extracts confirmed the presence of versican in the nucleus, and multifluorescent immunostaining showed strong colocalization of versican and nucleolin, suggesting a nucleolar localization of versican in nondividing cells. In dividing valve interstitial cells, a strong signal for versican was observed in and around the condensed chromosomes during the various stages of mitosis. Multifluorescent immunostaining for versican and tubulin revealed versican aggregated at opposing poles of the mitotic spindle during metaphase. Knockdown of versican expression using siRNA disrupted the organization of the mitotic spindle and led to the formation of multipolar spindles during metaphase. CONCLUSIONS Collectively, these data suggest an intracellular function for versican in vascular cells where it appears to play a role in mitotic spindle organization during cell division. These observations open a new avenue for studies of versican, suggesting even more diverse roles in vascular health and disease.
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Affiliation(s)
- Jon M Carthy
- UBC James Hogg Research Centre, Institute for Heart+Lung Health, Department of Pathology and Laboratory Medicine, University of British Columbia, Providence Health Care, Vancouver, BC, Canada
| | - Thomas Abraham
- UBC James Hogg Research Centre, Institute for Heart+Lung Health, Department of Pathology and Laboratory Medicine, University of British Columbia, Providence Health Care, Vancouver, BC, Canada
| | - Anna J Meredith
- UBC James Hogg Research Centre, Institute for Heart+Lung Health, Department of Pathology and Laboratory Medicine, University of British Columbia, Providence Health Care, Vancouver, BC, Canada
| | - Seti Boroomand
- UBC James Hogg Research Centre, Institute for Heart+Lung Health, Department of Pathology and Laboratory Medicine, University of British Columbia, Providence Health Care, Vancouver, BC, Canada
| | - Bruce M McManus
- UBC James Hogg Research Centre, Institute for Heart+Lung Health, Department of Pathology and Laboratory Medicine, University of British Columbia, Providence Health Care, Vancouver, BC, Canada.
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20
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Labrosse MR, Beller CJ, Boodhwani M, Hudson C, Sohmer B. Subject-specific finite-element modeling of normal aortic valve biomechanics from 3D+t TEE images. Med Image Anal 2015; 20:162-72. [DOI: 10.1016/j.media.2014.11.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 07/25/2014] [Accepted: 11/07/2014] [Indexed: 01/16/2023]
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21
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Sider KL, Zhu C, Kwong AV, Mirzaei Z, de Langé CFM, Simmons CA. Evaluation of a porcine model of early aortic valve sclerosis. Cardiovasc Pathol 2014; 23:289-97. [PMID: 24998316 DOI: 10.1016/j.carpath.2014.05.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 05/05/2014] [Accepted: 05/28/2014] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND Calcific aortic valve disease (CAVD) is associated with significant cardiovascular morbidity. While late-stage CAVD is well-described, early pathobiological processes are poorly understood due to the lack of animal models that faithfully replicate early human disease. Here we evaluated a hypercholesterolemic porcine model of early diet-induced aortic valve sclerosis. METHODS Yorkshire swine were fed either a standard or high-fat/high-cholesterol diet for 2 or 5 months. Right coronary aortic valve leaflets were excised and analyzed (immuno)histochemically. RESULTS Early human-like proteoglycan-rich onlays formed between the endothelial layer and elastic lamina in the fibrosa layer of valve leaflets, with accelerated formation associated with hypercholesterolemia (P<.05). Lipid deposition was more abundant in hypercholesterolemic swine (P<.001), but was present in a minority (28%) of onlays. No myofibroblasts, MAC387-positive macrophages, or fascin-positive dendritic cells were detected in 2-month onlays, with only scarce myofibroblasts present at 5 months. Cells that expressed osteochondral markers Sox9 and Msx2 were preferentially found in dense proteoglycan-rich onlays (P<.05) and with hypercholesterolemia (P<.05). Features of more advanced human CAVD, including calcification, were not observed in this necessarily short study. CONCLUSIONS Early aortic valve sclerosis in hypercholesterolemic swine is characterized by the formation of proteoglycan-rich onlays in the fibrosa, which can occur prior to significant lipid accumulation, inflammatory cell infiltration, or myofibroblast activation. These characteristics mimic those of early human aortic valve disease, and thus the porcine model has utility for the study of early valve sclerosis.
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Affiliation(s)
- Krista L Sider
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, Canada, M5S 3G9
| | - Cuilan Zhu
- Department of Animal and Poultry Science, University of Guelph, 50 Stone Road East, Building #70, Guelph, Ontario, Canada, N1G 2W1
| | - Andrea V Kwong
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, Canada, M5S 3G9
| | - Zahra Mirzaei
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, Canada, M5S 3G9
| | - Cornelius F M de Langé
- Department of Animal and Poultry Science, University of Guelph, 50 Stone Road East, Building #70, Guelph, Ontario, Canada, N1G 2W1
| | - Craig A Simmons
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, Canada, M5S 3G9; Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada, M5S 3G8.
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22
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Matsumaru I, Eishi K, Hashizume K, Kawano H, Tsuneto A, Hayashi T. Clinical and pathological features of degenerative mitral valve disease: billowing mitral leaflet versus fibroelastic deficiency. Ann Thorac Cardiovasc Surg 2013; 20:987-94. [PMID: 24284503 DOI: 10.5761/atcs.oa.13-00168] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
PURPOSE Degenerative mitral valve disease is distinguished with billowing mitral leaflet (BML) or fibroelastic deficiency (FED). The purpose of this study is to evaluate the clinical characteristics and the pathohistological differences between BML and FED. METHODS A total of 73 patients who diagnosed as degenerative mitral valve disease pathologically after mitral valve surgery for severe mitral regurgitation were enrolled. On the basis of echocardiographic features and gross appearances, they were classified as BML (9 cases) and FED (64 cases). RESULTS In the BML group, multiple segments of the leaflet showed billowing with elongated chordae. Therefore excessive valve tissue needed to be removed by multiple resection and suture. The FED patients had focal myxomatous changes with ruptured chordae, a single resection and suture was frequently employed. In pathological examination, the valve thickness of the BML was nearly twice as thick as the FED, and the mucopolysaccharide accumulation of the Spongiosa in the BML was over 50%, while 30% in the FED. CONCLUSION BML presents the characteristic valve thickening due to its abnormal production of mucopolysaccharide. Since excessive tissue was voluminous in the BML, high-grade plasty techniques, such as combination of multiple resection and chordal reconstruction were required.
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Affiliation(s)
- Ichiro Matsumaru
- Department of Cardiovascular Surgery, Nagasaki University Hospital, Nagasaki, Nagasaki, Japan
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23
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Kochtebane N, Choqueux C, Michel JB, Jacob MP. [Aortic stenosis and extracellular matrix remodeling]. Biol Aujourdhui 2012; 206:135-43. [PMID: 22748051 DOI: 10.1051/jbio/2012015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Indexed: 11/14/2022]
Abstract
Valvular heart diseases represent an important public health burden. With the decrease in the incidence of rheumatic heart disease, calcific aortic stenosis has now become the most common valvular disease in Western countries. Its prevalence increases with age, such that its affects about 4% of the elderly population and it is the most common motive for valve replacement. Several tissue abnormalities were observed in aortic valves from patients suffering from aortic stenosis: presence of large calcium deposits, inflammatory cells, lipids, and neocapillaries as well as extracellular matrix remodeling. The aortic valves show three characteristic layers: the fibrosa composed mainly of collagen bundles, the spongiosa which consists of a proteoglycan matrix, and the ventricularis which contains several elastic lamellae. The components of the extracellular matrix are synthesized by valvular mesenchymal cells. The turn-over of collagen and elastic fibers is low; the other macromolecules are more rapidly synthesized and hydrolysed. Serine proteases such as enzymes of the fibrinolytic system and matrix metalloproteinases play a role in the remodeling of the extracellular matrix. The hydrolysis of adhesive proteins, such as fibronectin, by plasmin triggers the apoptosis of valvular (myo)fibroblasts, a biological process named anoikis. Cellular events and extracellular matrix remodeling thus participate to the evolution of aortic valves towards aortic stenosis.
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Affiliation(s)
- Najlah Kochtebane
- INSERM UMR 698, Hématologie, Bio-Ingénierie et Remodelage Cardiovasculaire, Université Paris 7 Denis Diderot, Hôpital Bichat-Claude Bernard, 46 rue Henri Huchard, 75877 Paris Cedex 18, France
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24
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Martin C, Sun W. Biomechanical characterization of aortic valve tissue in humans and common animal models. J Biomed Mater Res A 2012; 100:1591-9. [PMID: 22447518 DOI: 10.1002/jbm.a.34099] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 01/20/2012] [Accepted: 01/24/2012] [Indexed: 12/26/2022]
Abstract
Aortic valve disease develops in an escalating fashion in elderly patients. Current treatments including total valve replacement and valve repair techniques are still suboptimal. A thorough understanding of the animal and human valve tissue properties, particularly their differences, is crucial for the establishment of preclinical animal models and strategies for evaluating new valve treatment techniques, such as transcatheter valve intervention and tissue engineered valves. The goal of this study was to characterize and compare the biomechanical properties and histological structure of healthy ovine, porcine, and human aortic valve leaflets. The biaxial mechanical properties of the aortic valve leaflets of 10 ovine (∼1 year), 10 porcine (6-9 months), and 10 aged human (80.6 ± 8.34) hearts were quantified. Tissue microstructure was analyzed via histological techniques. Aged human aortic valve leaflets were significantly less compliant than both ovine and porcine leaflets, with the ovine leaflets being the most compliant. Histological analysis revealed structural differences between the species: the human and porcine leaflets contained more collagen and elastin than the ovine leaflets. Significant mechanical and structural differences in the aortic valve tissues of 6- to 9-month-old porcine models and 1-year-old ovine models with respect to those of aged humans, suggest that these animal models may not be representative of the typical patient undergoing aortic valve replacement.
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Affiliation(s)
- Caitlin Martin
- Tissue Mechanics Laboratory, Biomedical Engineering Program and Mechanical Engineering Department, University of Connecticut, Storrs, Connecticut 06269, USA
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25
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Differentiating the aging of the mitral valve from human and canine myxomatous degeneration. J Vet Cardiol 2012; 14:31-45. [PMID: 22364720 DOI: 10.1016/j.jvc.2011.11.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 11/16/2011] [Accepted: 11/30/2011] [Indexed: 12/11/2022]
Abstract
During the course of both canine and human aging, the mitral valve remodels in generally predictable ways. The connection between these aging changes and the morbidity and mortality that accompany pathologic conditions has not been made clear. By exploring work that has investigated the specific valvular changes in both age and disease, with respect to the cells and the extracellular matrix found within the mitral valve, heretofore unexplored connections between age and myxomatous valve disease can be found. This review addresses several studies that have been conducted to explore such age and disease related changes in extracellular matrix, valvular endothelial and interstitial cells, and valve innervation, and also reviews attempts to correlate aging and myxomatous disease. Such connections can highlight avenues for future research and help provide insight as to when an individual diverts from an aging pattern into a diseased pathway. Recognizing these patterns and opportunities could result in earlier intervention and the hope of reduced morbidity and mortality for patients.
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26
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Corcoran TB, Hillyard S. Cardiopulmonary aspects of anaesthesia for the elderly. Best Pract Res Clin Anaesthesiol 2011; 25:329-54. [DOI: 10.1016/j.bpa.2011.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 07/12/2011] [Indexed: 02/03/2023]
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Patient-to-patient variability in autologous pericardial matrix scaffolds for cardiac repair. J Cardiovasc Transl Res 2011; 4:545-56. [PMID: 21695575 DOI: 10.1007/s12265-011-9293-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Accepted: 06/10/2011] [Indexed: 01/15/2023]
Abstract
The pursuit of alternate therapies for end-stage heart failure post-myocardial infarction has led to the development of a variety of in situ gelling materials to be used as cellular or acellular scaffolds for cardiac repair. Previously, a protocol was established to decellularize human and porcine pericardia and process the extracellular matrix (ECM) into an injectable form. The resulting gels were found to retain components of the native extracellular matrix; cell infiltration was facilitated in vivo, and neovascularization was observed by 2 weeks. However, the assertion that an injectable form of human pericardial tissue could be a potentially autologous scaffold for myocardial tissue engineering requires assessment of the patient-to-patient variability. With this work, seven human pericardia from a relevant patient demographic are processed into injectable matrix materials that gel when brought to physiologic conditions. The resulting materials are compared with respect to their protein composition, glycosaminoglycan content, in vitro degradation, in vivo gelation, and microstructure. It is observed that a diminished collagen content in a subset of samples prevents in vitro gelation but not in vivo gelation at lower ECM concentrations. The structure is similarly fibrous and porous across all samples, implying the cell infiltration may be similarly facilitated. The biochemical composition as characterized by tandem mass spectrometry is comparable; basic ECM components are conserved across all samples, and the presence of a wide variety of ECM proteins and glycoproteins demonstrate the retention of biochemical complexity post-processing. It is concluded that the variability within human pericardial tissue specimens does not prevent them from being processed into injectable scaffolds; therefore, pericardial tissue offers a promising source as an autologous, injectable biomaterial scaffold.
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28
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Stephens EH, de Jonge N, McNeill MP, Durst CA, Grande-Allen KJ. Age-related changes in material behavior of porcine mitral and aortic valves and correlation to matrix composition. Tissue Eng Part A 2010; 16:867-78. [PMID: 19814589 DOI: 10.1089/ten.tea.2009.0288] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Recent studies showing significant changes in valvular matrix composition with age offer design criteria for age-specific tissue-engineered heart valves. However, knowledge regarding aging-related changes in valvular material properties is limited. Therefore, 6-week, 6-month, and 6-year-old porcine aortic valves (AV) and mitral valves (MV) were subjected to uniaxial tensile testing. In addition to standard material parameters, the radius of transition curvature (RTC) was measured to assess the acuteness of the transition region of the tension-strain curve. Radially, the MV had greater stiffness and a smaller RTC compared with the AV. Circumferentially, the center of the MV anterior leaflet (MVAC) had the highest stiffness (MVAC > AV > MV free edge [MVF]), greater stress relaxation (MVAC > MVF/AV), lowest extensibility (MVAC < AV < MVF), and smaller RTC compared with MVF (AV < MVAC < MVF). AV and MV radial strips had a larger RTC compared with circumferential strips. Aging elevated stiffness for MV and AV radial and circumferential strips, elevated stress relaxation in AV and MVF circumferential strips, and increased RTC for MV radial and MVF circumferential strips. In conclusion, there are significant age-related differences in the material properties of heart valves, which parallel differences in tissue composition and structure, likely impact valve function, and highlight the need for age-specific design goals for tissue-engineered heart valves.
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29
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Stephens EH, Post AD, Laucirica DR, Grande-Allen KJ. Perinatal changes in mitral and aortic valve structure and composition. Pediatr Dev Pathol 2010; 13:447-58. [PMID: 20536360 PMCID: PMC4667799 DOI: 10.2350/09-11-0749-oa.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
At birth, the mechanical environment of valves changes radically as fetal shunts close and pulmonary and systemic vascular resistances change. Given that valves are reported to be mechanosensitive, we investigated remodeling induced by perinatal changes by examining compositional and structural differences of aortic and mitral valves (AVs, MVs) between 2-day-old and 3rd fetal trimester porcine valves using immunohistochemistry and Movat pentachrome staining. Aortic valve composition changed more with birth than the MV, consistent with a greater change in AV hemodynamics. At 2 days, AV demonstrated a trend of greater versican and elastin (P = 0.055), as well as greater hyaluronan turnover (hyaluronan receptor for endocytosis, P = 0.049) compared with the 3rd-trimester samples. The AVs also demonstrated decreases in proteins related to collagen synthesis and fibrillogenesis with birth, including procollagen I, prolyl 4-hydroxylase, biglycan (all P ≤ 0.005), and decorin (P = 0.059, trend). Both AVs and MVs demonstrated greater delineation between the leaflet layers in 2-day-old compared with 3rd-trimester samples, and AVs demonstrated greater saffron-staining collagen intensity, suggesting more mature collagen in 2-day-old compared with 3rd-trimester samples (each P < 0.05). The proportion of saffron-staining collagen also increased in AV with birth (P < 0.05). The compositional and structural changes that occur with birth, as noted in this study, likely are important to proper neonatal valve function. Furthermore, normal perinatal changes in hemodynamics often do not occur in congenital valve disease; the corresponding perinatal matrix maturation may also be lacking and could contribute to poor function of congenitally malformed valves.
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Affiliation(s)
| | - Allison D. Post
- Department of Bioengineering, Rice University, Houston, TX, USA
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Droogmans S, Roosens B, Cosyns B, Degaillier C, Hernot S, Weytjens C, Garbar C, Caveliers V, Pipeleers-Marichal M, Franken PR, Lahoutte T, Schoors D, Van Camp G. Cyproheptadine prevents pergolide-induced valvulopathy in rats: an echocardiographic and histopathological study. Am J Physiol Heart Circ Physiol 2009; 296:H1940-8. [PMID: 19346455 DOI: 10.1152/ajpheart.01177.2008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Serotonergic drugs, such as pergolide, have been associated with the development of cardiac valvular myxoid thickening and regurgitation in humans and more recently in rats. These effects are potentially mediated by the 5-hydroxytryptamine (5-HT)(2B) receptor (5-HT(2B)R). Therefore, we sought to determine whether cyproheptadine, a 5-HT(2B)R antagonist, might prevent toxic valvulopathy in an animal model of pergolide-induced valvular heart disease. For this purpose, 50 male Wistar rats received daily intraperitoneal injections of pergolide (0.5 mg/kg, n = 14), pergolide (0.5 mg/kg) combined with cyproheptadine (10 mg/kg, n = 12), cyproheptadine (10 mg/kg, n = 12), or no injections (control, n = 12) for 20 wk. Echocardiography was performed blindly at baseline and at 10 and 20 wk followed by pathology. At baseline, no differences between groups were found with echocardiography. At 20 wk, aortic regurgitation was present in all pergolide-treated animals, whereas it was less frequently observed in the other groups (P < 0.0001). For the other valves, this difference was less pronounced. On histopathology, not only aortic but also mitral valves were thicker, myxoid, and exhibited more 5-HT(2B)R-positive cells in pergolide-treated animals compared with the other groups. Moreover, regurgitant aortic and mitral valves were thicker than nonregurgitant aortic and mitral valves. In conclusion, we found that cyproheptadine prevented pergolide-induced valvulopathy in rats, which was associated with a reduced number of 5-HT(2B)R-positive valvular cells. This may have important clinical implications for the prevention of serotonergic drug-induced valvular heart disease.
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Affiliation(s)
- Steven Droogmans
- Departmnet of Cardiology, Universitair Ziekenhuis Brussel, Brussels 1090, Belgium.
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Stephens EH, Chu CK, Grande-Allen KJ. Valve proteoglycan content and glycosaminoglycan fine structure are unique to microstructure, mechanical load and age: Relevance to an age-specific tissue-engineered heart valve. Acta Biomater 2008; 4:1148-60. [PMID: 18448399 PMCID: PMC10615646 DOI: 10.1016/j.actbio.2008.03.014] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 02/01/2008] [Accepted: 03/20/2008] [Indexed: 02/02/2023]
Abstract
This study characterized valve proteoglycan and glycosaminoglycan composition during development and aging. This knowledge is important for the development of age-specific tissue-engineered heart valves as well as treatments for age-specific valvulopathies. Aortic valves and mitral valves from first-third trimester, 6-week, 6-month and 6-year-old pigs were examined using immunohistochemistry for versican, biglycan, decorin and hyaluronan, as well as elastin and fibrillin. The fine structure of glycosaminoglycans was examined by fluorophore-assisted carbohydrate electrophoresis. Decorin expression was strongest in the 6-year-old valves, particularly in the aortic valve spongiosa. The quantity of iduronate was also highest in the 6-year-old valves. The central tensile-loading region of the anterior mitral leaflet demonstrated reduced glycosaminoglycan content, chain length and hydration and a larger fraction of 4-sulfated iduronate and lower fraction of 6-sulfation. With age, the anterior leaflet center showed a further increase in 4-sulfated iduronate and decrease in 6-sulfation. In contrast, the anterior leaflet free edge showed decreased iduronate and 4-sulfated glucuronate content with age. The young aortic valve was similar to the mitral valve free edge with a higher concentration of glycosaminoglycans and 6-rather than 4-sulfation, but aged to resemble the mitral anterior leaflet center, with an increase in 4-sulfated iduronate content and a decrease in the 6-sulfation fraction. Elastin and fibrillin often co-localized with the proteoglycans studied, but elastin co-localized most specifically with versican. In conclusion, composition and fine structure changes in valve proteoglycans and glycosaminoglycans with age are complex and distinct within valve type, histological layers and regions of different mechanical loading.
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Affiliation(s)
- Elizabeth H Stephens
- Department of Bioengineering, Rice University, P.O. Box 1892 - MS142, Houston, TX 77251-1892, USA
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Abundance and location of proteoglycans and hyaluronan within normal and myxomatous mitral valves. Cardiovasc Pathol 2008; 18:191-7. [PMID: 18621549 DOI: 10.1016/j.carpath.2008.05.001] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 04/21/2008] [Accepted: 05/05/2008] [Indexed: 11/20/2022] Open
Abstract
INTRODUCTION Extracellular matrix changes occur in many heart valve pathologies. For example, myxomatous mitral valves are reported to contain excess proteoglycans and hyaluronan. However, it is unknown which specific proteoglycans are altered in myxomatous valves. Because proteoglycans perform varied functions in connective tissues, this study was designed to identify and localize three matrix-associated proteoglycans, as well as hyaluronan and the hyaluronan receptor for endocytosis, within myxomatous and normal mitral valves. METHODS Human mitral posterior leaflets (control, n=6-9; myxomatous, n=14-21; mean age, 61 years for all groups) were histochemically stained for proteoglycan core proteins, hyaluronan, and the hyaluronan receptor for endocytosis. Stain intensity was semiquantitatively graded to determine differences in marker abundance between normal and myxomatous valves. The proteoglycans were localized to different regions of the leaflet by correspondence to parallel Movat-stained sections. RESULTS The proteoglycans decorin, biglycan, and versican were more abundant in myxomatous valves than in normal controls (P<.03). There was a gender effect on proteoglycan presence, but no age-related trends were observed. Hyaluronan and the hyaluronan receptor for endocytosis were distributed throughout all valves. There was no significant difference in hyaluronan between groups, but expression of the hyaluronan receptor for endocytosis was reduced in myxomatous valves compared to normal controls (P<.002). CONCLUSION Excess decorin, biglycan, and versican may be associated with the remodeling of other matrix components in myxomatous mitral valves. Decreased expression of the hyaluronan receptor for endocytosis in myxomatous valves suggests that hyaluronan metabolism could be altered in myxomatous mitral valve disease. These findings contribute towards elucidating the pathogenesis of myxomatous mitral valve disease and developing potential new therapies.
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Migneco F, Hollister SJ, Birla RK. Tissue-engineered heart valve prostheses: ‘state of the heart’. Regen Med 2008; 3:399-419. [DOI: 10.2217/17460751.3.3.399] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In this article, we will review the current state of the art in heart valve tissue engineering. We provide an overview of mechanical and biological replacement options, outlining advantages and limitations of each option. Tissue engineering, as a field, is introduced, and specific aspects of valve tissue engineering are discussed (e.g., biomaterials, cells and bioreactors). Technological hurdles, which need to be overcome for advancement of the field, are also discussed.
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Affiliation(s)
- Francesco Migneco
- Section of Cardiac Surgery, the University of Michigan, B560 Medical Science Research Building II, 1150 West Medical Center Drive, Ann Arbor, MI 48109-2110, USA
| | - Scott J Hollister
- Department of Biomedical Engineering, the University of Michigan, Ann Arbor, MI 48109-2110, USA
| | - Ravi K Birla
- Section of Cardiac Surgery, the University of Michigan, B560 Medical Science Research Building II, 1150 West Medical Center Drive, Ann Arbor, MI 48109-2110, USA
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Donnelly KB. Cardiac Valvular Pathology: Comparative Pathology and Animal Models of Acquired Cardiac Valvular Diseases. Toxicol Pathol 2008; 36:204-17. [DOI: 10.1177/0192623307312707] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recent voluntary withdrawal of the ergoline-derivative Alzheimers’ drug Pergolide (Permax) resulting from demonstrated risk of cardiac valve injury illustrates the increased importance of valve injury in pharmaceutical toxicology. Following the 2001 landmark discovery of cardiac valve injury associated with the widely prescribed anti-obesity drug combination fenfluramine-phentermine, and subsequent withdrawal, the need to understand and assess cardiac valve biology and pathology both preclinically and clinically has been accentuated. Unique aspects of the developmental biology, anatomy, and physiology of cardiac valves compared to main cardiac tissue have been discovered, and key elements of the pathophysiology of various valvular injury mechanisms have been described. Although general clinical cardiac valvular disease in humans has been well characterized, animal modeling of valvular injury has proved to be difficult and undersubscribed. Additionally, both the preclinical, pharmaceutical, toxicologic assessment of valvular injury and the understanding of species-comparative valvular pathology have been limited. As discoveries and awareness grows, the purpose of this paper is to review the structure and function of cardiac valves, mechanisms, and outcomes of the common acquired human cardiac valve diseases, including those that are drug-related; to summarize comparative laboratory animal valvular pathology; and to review the literature of contemporary animal models of valvular injury.
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Affiliation(s)
- Kevin B. Donnelly
- Lilly Research Laboratories, Eli Lilly and Co., Greenfield, Indiana, USA
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Liang W, McDonald P, McManus B, van Breemen C, Wang X. P2Y2 Receptor-Mediated Ca2+ Signaling and Spontaneous Ca2+ Releases in Human Valvular Myofibroblasts. Int Heart J 2008; 49:221-36. [DOI: 10.1536/ihj.49.221] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Willmann Liang
- School of Biological Sciences, Nanyang Technological University
| | - Paul McDonald
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia
| | - Bruce McManus
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia
| | - Cornelis van Breemen
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia
| | - Xiaodong Wang
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia
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Blevins TL, Peterson SB, Lee EL, Bailey AM, Frederick JD, Huynh TN, Gupta V, Grande-Allen KJ. Mitral valvular interstitial cells demonstrate regional, adhesional, and synthetic heterogeneity. Cells Tissues Organs 2007; 187:113-22. [PMID: 17851228 PMCID: PMC3513383 DOI: 10.1159/000108582] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Because various regions of the mitral valve contain distinctive extracellular matrix enabling the tissues to withstand diverse mechanical environments, we investigated phenotype and matrix production of porcine valvular interstitial cells (VICs) from different regions. METHODS VICswere isolated from the chordae (MCh), the center of the anterior leaflet (AlCtr), and the posterior leaflet free edge (PlFree), then assayed for metabolic, growth, and adhesion rates; collagen and glycosaminoglycan (GAG) production, and phenotype using biochemical assays, flow cytometry, and immunocytochemistry. RESULTS The AlCtr VICs exhibited the fastest metabolism but slowest growth. PlFree cells grew the fastest, but demonstrated the least smooth muscle alpha-actin, vimentin, and internal complexity. AlCtr VICs secreted less collagen into the culture medium but more 4-sulfated GAGs than other cells. Adhesion-based separation resulted in altered secretion of sulfated GAGs by MCh and AlCtr cells but not by the PlFree cells. CONCLUSIONS VICs isolated from various regions of the mitral valve demonstrate phenotypic differences in culture, corresponding to the ability of the mitral valve to accommodate the physical stresses or altered hemodynamics that occur with injury or disease. Further understanding of VIC and valve mechanobiology could lead to novel medical or tissue engineering approaches to treat valve diseases.
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Affiliation(s)
- Tracy L. Blevins
- Rice University, Department of Bioengineering, Houston, TX 77005
| | | | - Elaine L. Lee
- Case Western Reserve University, Department of Biomedical Engineering, Cleveland, OH, 44106
| | - Annie M. Bailey
- Howard University, Department of Biology, Washington, DC, 20059
| | | | - Thanh N. Huynh
- Rice University, Department of Bioengineering, Houston, TX 77005
| | - Vishal Gupta
- Rice University, Department of Bioengineering, Houston, TX 77005
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Przybyło M, Stepień E, Pfitzner R, Lityńska A, Sadowski J. Age Effect on Human Aortic Valvular Glycoproteins. Arch Med Res 2007; 38:495-502. [PMID: 17560454 DOI: 10.1016/j.arcmed.2007.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Accepted: 02/02/2007] [Indexed: 10/23/2022]
Abstract
BACKGROUND The aortic valve has been the subject of many hemodynamic studies but, to our knowledge, posttranslational modification of human valve proteins has not yet been studied. Thus, the aim of this study was to determine whether any age-related changes in the protein composition of normal human aortic valves and their glycosylation pattern could be observed. METHODS Aortic valves harvested from male cadaveric donors free of cardiovascular diseases were divided into four age groups: I, mean age 21 years; II, 30 years; III, 41 years; IV, 51 years. Proteins were separated by SDS-PAGE and transferred to PVDF membranes. Identification of monosaccharide moieties or oligosaccharide units was performed with the use of eight lectins of narrow specificity: Galantus nivalis agglutinin, Sambucus nigra agglutinin, Maackia amurensis agglutinin, Datura stramonium agglutinin, Aleuria aurantia agglutinin, Arachis hypogeae agglutinin, Phaseolus vulgaris agglutinin, and Lycopersicon esculentum agglutinin. RESULTS Isolated proteins showed no age-related changes in SDS-PAGE protein profile, contrary to their glycosylation. Protein sialylation, number of tri/tetraantennary complex glycans, proteins having terminal galactose and polylactosaminyl units increased with age, whereas protein fucosylation showed the opposite relationship. Moreover, groups III and IV possessed a larger number of proteins bearing high-mannose and/or hybrid-type glycans, and the quantity of these structures seemed to change, in particular proteins, with the age of donors. CONCLUSIONS Our results clearly demonstrate that glycosylation profile in human aortic proteins is associated with the age of the donor.
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Affiliation(s)
- Małgorzata Przybyło
- Department of Glycoconjugate Biochemistry, Institute of Zoology, Jagiellonian University, Kraków, Poland.
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Balguid A, Rubbens MP, Mol A, Bank RA, Bogers AJJC, van Kats JP, de Mol BAJM, Baaijens FPT, Bouten CVC. The Role of Collagen Cross-Links in Biomechanical Behavior of Human Aortic Heart Valve Leaflets—Relevance for Tissue Engineering. ACTA ACUST UNITED AC 2007; 13:1501-11. [PMID: 17518750 DOI: 10.1089/ten.2006.0279] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A major challenge in tissue engineering of functional heart valves is to determine and mimic the dominant tissue structures that regulate heart valve function and in vivo survival. In native heart valves, the anisotropic matrix architecture assures sustained and adequate functioning under high-pressure conditions. Collagen, being the main load-bearing matrix component, contributes significantly to the biomechanical strength of the tissue. This study investigates the relationship between collagen content, collagen cross-links, and biomechanical behavior in human aortic heart valve leaflets and in tissue-engineered constructs. In the main loading direction (circumferential) of native valve leaflets, a significant positive linear correlation between modulus of elasticity and collagen cross-link concentration was found, whereas no correlation between modulus of elasticity and collagen content was found. Similar findings were observed in tissue-engineered constructs, where cross-link concentration was higher for dynamically strained constructs then for statically cultured controls. These findings suggest a dominant role for collagen cross-links over collagen content with respect to biomechanical tissue behavior in human heart valve leaflets. They further suggest that dynamic tissue straining in tissue engineering protocols can enhance cross-link concentration and biomechanical function.
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Affiliation(s)
- Angelique Balguid
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
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Pedersen LG, Offenberg H, Moesgaard SG, Thomsen PD, Pedersen HD, Olsen LH. Transcription levels of endothelin-1 and endothelin receptors are associated with age and leaflet location in porcine mitral valves. ACTA ACUST UNITED AC 2007; 54:113-8. [PMID: 17381672 DOI: 10.1111/j.1439-0442.2007.00894.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aim of the study was to investigate the expression levels of endothelin-1 (ET-1) and ET(A) and ET(B) receptors (ET(A)-R and ET(B)-R) in porcine mitral valves and associate the transcription levels to age, leaflet location and deposition of mucopolysaccharides (MPS). Tissue samples from the chordal and inter-chordal insertion area of the anterior mitral valve leaflet from 11 sows (> or = 2 years of age) and 10 slaughter pigs (approximately 6 months old) were obtained and the relative gene expression levels of ET-1, ET(A)-R and ET(B)-R measured by semi-quantitative real-time PCR. A separate tissue sample was taken for histopathological grading of MPS deposition. The transcription levels of ET-1 (P < 0.0001) and ET(A)-R (P < 0.0004) were significantly higher in leaflets from the sows compared with slaughter pigs. The gene expression of ET(B)-R was not associated to age (P = 0.38), but increased in chordal insertion areas compared with inter-chordal areas (P = 0.01). The expression of ET-1 and ET(A)-R mRNA did not differ significantly between the two leaflet locations. The valve leaflets from sows had a significantly increased degree of MPS deposition compared with slaughter pigs upon histological examination (P = 0.04). In conclusion, an age-related valvular degeneration is observed in porcine mitral valve leaflets and ET-1 is suggested to be involved through action of both ET(A) and ET(B) receptors.
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Affiliation(s)
- L G Pedersen
- Department of Basic Animal and Veterinary Sciences, The Royal Vetinary and Agricultural University, Copenhagen, Denmark
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Abstract
Degenerative processes result in changes in both the aortic and mitral valves. For example, degenerative changes may lead to significant aortic stenosis or myxomatous mitral valves. Flows through each valve are determined not only by the properties of the valve itself, but also by the properties of proximal and distal chambers, which also undergo changes with age and diseases associated with the elderly, such as hypertension and coronary artery disease. Assessment of valvular performance should consider the effects of atrial-ventricular coupling (for the mitral valve) or ventricular-arterial coupling (for the aortic valve). Design of therapy or intervention should accordingly consider effects on the system as a whole.
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Affiliation(s)
- Michael D VanAuker
- Department of Chemical Engineering, Biomedical Engineering Program, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620, USA.
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Elangbam CS, Wehe JG, Barton JC, Krull DL, Nyska A, Crabbs T, Kissling GE. Evaluation of glycosaminoglycans content and 5-hydroxytryptamine 2B receptor in the heart valves of Sprague-Dawley rats with spontaneous mitral valvulopathy – A possible exacerbation by dl-amphetamine sulfate in Fischer 344 rats? ACTA ACUST UNITED AC 2006; 58:89-99. [PMID: 16996724 DOI: 10.1016/j.etp.2006.08.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Accepted: 08/09/2006] [Indexed: 10/24/2022]
Abstract
Spontaneous valvulopathy has been described as nodular or segmental thickenings composed of fibromyxoid tissue in the subendocardium of various valve-leaflets in aging rats, but its pathogenesis and significance are incompletely understood. In this study, we examined the 5-hydroxytryptamine 2B receptor (5HT2BR) expression and characterization of extracellular matrix (ECM) components, and related these to the presence of valvulopathy in the mitral valve-leaflet (spontaneous mitral valvulopathy, SMV) of Sprague-Dawley (SD) rats. We also examined hearts from Fischer 344 (F344) rats treated with dl-amphetamine sulfate for 103 weeks to further explore the potential for drug-induced exacerbation of SMV. In SD rats, valve-leaflets with SMV exhibited a greater valve thickness, a higher amount of glycosaminoglycans, a lower amount of collagen and increased number of 5HT2BR-positive cells. Our data on morphology and ECM changes showed a striking similarity between SMV in SD rats and anorexigen-associated valvulopathy in humans, and increased 5HT2BR-positive cells in SMV implies that 5HT2BR may play a role in pathogenesis. Further, increased incidence and severity of SMV in F344 rats by treatment with dl-amphetamine suggest that a drug-induced exacerbation of SMV may exist in rats. However, additional research is needed to confirm a role for 5HT2BR in the pathogenesis of SMV in SD rats, and to further characterize the relationship between dl-amphetamine treatment and exacerbation of SMV in F344 rats.
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Edwards MB, Draper ERC, Hand JW, Taylor KM, Young IR. Mechanical testing of human cardiac tissue: some implications for MRI safety. J Cardiovasc Magn Reson 2006; 7:835-40. [PMID: 16353445 DOI: 10.1080/10976640500288149] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
PURPOSE The effects of aging on tissue strength and its ability to withstand forces associated with MRI have not been investigated. This study aimed to determine the forces required to cause partial or total detachment of a heart valve prosthesis in patients with age-related degenerative diseases exposed to MRI. METHODS Eighteen tissue samples excised during routine heart valve replacement surgery were subjected to a suture pull-out test using a tensile materials testing machine. Five preconditioning cycles were applied before commencing the final destructive test. The test was complete when the sample ruptured and the suture was pulled completely free from the tissue. Results were compared with previously calculated magnetically induced forces at 4.7 T. RESULTS All tissue samples displayed a basic failure pattern. Mean forces required to cause initial yield and total rupture were 4.0 N (+/- 3.3 N) and 4.9 N (+/- 3.6 N), respectively. Significant factors determining initial yield were stenosed calcific tissue (p < .01), calcific degeneration (single pathology) (p < .04) and tissue stiffness (p < .01). Calcific degeneration (p < .03) and tissue stiffness (p < .03) were also significant in determining maximum force required to cause total rupture. CONCLUSION Specific age-related degenerative cardiac diseases stiffen and strengthen tissue resulting in significant forces being required to pull a suture through valve annulus tissue. These forces are significantly greater than magnetically induced < 4.7 T. Therefore, patients with degenerative valvular diseases are unlikely to be at risk of valve dehiscence during exposure to static magnetic field < or = 4.7 T.
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Affiliation(s)
- Maria-Benedicta Edwards
- United Kingdom Heart Valve Registry, Department of Cardiothoracic Surgery, Hammersmith Hospital, UK
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Otto S, Baum T, Keller F. Sex-dependence of the relative number of elastic fibres in human heart valves. Ann Anat 2006; 188:153-8. [PMID: 16551012 DOI: 10.1016/j.aanat.2005.08.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The aim of the current study was to find out whether there are sex-dependent differences in the relative number of elastic fibres in human heart valves. Twenty-six aortic valves, 26 mitral valves, 33 pulmonary valves and 28 tricuspid valves of both sexes were obtained at autopsy from newborn to 89-year-old patients who died of noncardiac diseases. The quantitatively morphometric investigations were carried out on conventionally stained (Resorcinfuchsin) histological sections. The results were qualitatively examined with immuno-histochemically marked (anti-elastin antibodies) histological sections. Earlier examinations by Leutert [1976. Z. Gesamte Inn. Med. 31, 97-104] showed that the atrioventricular valves have the following layers: endothelium, atrial fibroelastic tissue (S1), fibrous tissue, ventricular fibroelastic tissue (S2) and endothelium. In our study, the ventricular side of the semilunar valves corresponds to side S1, whereas the vessel side corresponds to side S2. Three regions of interest were examined on each side of the valves: base, mid and tip. The number of elastic fibres per measuring area for all four human heart valves was significantly higher (p < 0,001) in fibroelastic tissue of side S1 than in fibroelastic tissue of side S2. Neither on side S1 nor on side S2 were there significant gender-related differences in the relative number of elastic fibres per measuring area. The results suggest a characteristic distribution of the elastic fibre system which is not sex-dependent but closely related to the function of the heart valves.
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Affiliation(s)
- S Otto
- Institute of Anatomy, University of Leipzig, Liebigstrasse 13, D-04103 Leipzig
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Qiu Q, Dunmore-Buyze J, Boughner DR, Lacefield JC. Evaluation of an algorithm for semiautomated segmentation of thin tissue layers in high-frequency ultrasound images. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2006; 53:324-34. [PMID: 16529107 DOI: 10.1109/tuffc.2006.1593371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
An algorithm consisting of speckle reduction by median filtering, contrast enhancement using top- and bottom-hat morphological filters, and segmentation with a discrete dynamic contour (DDC) model was implemented for nondestructive measurements of soft tissue layer thickness. Algorithm performance was evaluated by segmenting simulated images of three-layer phantoms and high-frequency (40 MHz) ultrasound images of porcine aortic valve cusps in vitro. The simulations demonstrated the necessity of the median and morphological filtering steps and enabled testing of user-specified parameters of the morphological filters and DDC model. In the experiments, six cusps were imaged in coronary perfusion solution (CPS) then in distilled water to test the algorithm's sensitivity to changes in the dimensions of thin tissue layers. Significant increases in the thickness of the fibrosa, spongiosa, and ventricularis layers, by 53.5% (p < 0.001), 88.5% (p < 0.001), and 35.1% (p = 0.033), respectively, were observed when the specimens were submerged in water. The intraobserver coefficient of variation of repeated thickness estimates ranged from 0.044 for the fibrosa in water to 0.164 for the spongiosa in CPS. Segmentation accuracy and variability depended on the thickness and contrast of the layers, but the modest variability provides confidence in the thickness measurements.
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Affiliation(s)
- Qiang Qiu
- University of Western Ontario, London, Ontario, N6A 5B9, Canada
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Merryman WD, Youn I, Lukoff HD, Krueger PM, Guilak F, Hopkins RA, Sacks MS. Correlation between heart valve interstitial cell stiffness and transvalvular pressure: implications for collagen biosynthesis. Am J Physiol Heart Circ Physiol 2006; 290:H224-31. [PMID: 16126816 DOI: 10.1152/ajpheart.00521.2005] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It has been speculated that heart valve interstitial cells (VICs) maintain valvular tissue homeostasis through regulated extracellular matrix (primarily collagen) biosynthesis. VICs appear to be phenotypically plastic, inasmuch as they transdifferentiate into myofibroblasts during valve development, disease, and remodeling. Under normal physiological conditions, transvalvular pressures (TVPs) on the right and left side of the heart are vastly different. Hence, we hypothesize that higher left-side TVPs impose larger local tissue stress on VICs, which increases their stiffness through cytoskeletal composition, and that this relation affects collagen biosynthesis. To evaluate this hypothesis, isolated ovine VICs from the four heart valves were subjected to micropipette aspiration to assess cellular stiffness, and cytoskeletal composition and collagen biosynthesis were quantified by using the surrogates smooth muscle α-actin (SMA) and heat shock protein 47 (HSP47), respectively. VICs from the aortic and mitral valves were significantly stiffer ( P < 0.001) than those from the pulmonary and tricuspid valves. Left-side isolated VICs contained significantly more ( P < 0.001) SMA and HSP47 than right-side VICs. Mean VIC stiffness correlated well ( r = 0.973) with TVP; SMA and HSP47 also correlated well ( r = 0.996) with one another. Assays were repeated for VICs in situ, and, as with in vitro results, left-side VIC protein levels were significantly greater ( P < 0.05). These findings suggest that VICs respond to local tissue stress by altering cellular stiffness (through SMA content) and collagen biosynthesis. This functional VIC stress-dependent biosynthetic relation may be crucial in maintaining valvular tissue homeostasis and also prove useful in understanding valvular pathologies.
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Affiliation(s)
- W David Merryman
- Dept. of Bioengineering, Univ. of Pittsburgh, Pittsburgh, PA 15219, USA
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Fondard O, Detaint D, Iung B, Choqueux C, Adle-Biassette H, Jarraya M, Hvass U, Couetil JP, Henin D, Michel JB, Vahanian A, Jacob MP. Extracellular matrix remodelling in human aortic valve disease: the role of matrix metalloproteinases and their tissue inhibitors. Eur Heart J 2005; 26:1333-41. [PMID: 15827062 DOI: 10.1093/eurheartj/ehi248] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
AIMS Aortic valve diseases are characterized by pathological remodelling of valvular tissue but the cellular and molecular effectors involved in these processes are not well known. The role of matrix metalloproteinase (MMP)-2, MMP-9, MMP-3, MMP-7, and tissue inhibitor of matrix metalloproteinase (TIMP)-1 and TIMP-2 are investigated here. METHODS AND RESULTS Histological analysis of pathological valves [aortic stenosis (AS) (n=49), aortic regurgitation (AR) (n=23)] and control valves (n=8) was performed. The main tissue abnormalities (calcification, inflammatory cells, and capillaries) observed in AS were less severe or absent in AR. However, both groups of pathological valves displayed similar histological signs of extracellular matrix (ECM) remodelling. Biochemical analysis of MMPs and TIMPs (gelatin and casein zymography and ELISA) was performed on valve extracts. MMP-2 activity was not significantly different in control and pathological valves. Increases in MMP-9 and MMP-3 in AS demonstrated an inflammatory state. Finally, there was a four- to seven-fold increase of TIMP-1 in pathological valves. TIMP-1, TIMP-2, and MMP-2 were synthesized by the valvular interstitial cells in primary culture. CONCLUSION This study demonstrates the involvement of the MMP/TIMP system in ECM remodelling of both AS and AR. These findings provide evidence of inflammatory injury more severe in AS than in AR and involvement of mesenchymal cell response.
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Affiliation(s)
- Olivier Fondard
- INSERM U 460, Bâtiment 13, Hôpital Bichat-Claude Bernard, 46 rue Henri Huchard, 75877 Paris Cedex 18, France
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Merryman WD, Huang HYS, Schoen FJ, Sacks MS. The effects of cellular contraction on aortic valve leaflet flexural stiffness. J Biomech 2005; 39:88-96. [PMID: 16271591 DOI: 10.1016/j.jbiomech.2004.11.008] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2004] [Accepted: 11/01/2004] [Indexed: 10/26/2022]
Abstract
The aortic valve (AV) leaflet contains a heterogeneous interstitial cell population composed predominantly of myofibroblasts, which contain both fibroblast and smooth muscle cell characteristics. The focus of the present study was to examine aortic valve interstitial cell (AVIC) contractile behavior within the intact leaflet tissue. Circumferential strips of porcine AV leaflets were mechanically tested under flexure, with the AVIC maintained in the normal, contracted, and contraction-inhibited states. Leaflets were flexed both with (WC) and against (AC) the natural leaflet curvature, both before and after the addition of 90 mM KCl to elicit cellular contraction. In addition, a natural basal tonus was also demonstrated by treating the leaflets with 10 microM thapsigargin to completely inhibit AVIC contraction. Results revealed a 48% increase in leaflet stiffness with AVIC contraction (from 703 to 1040 kPa, respectively) when bent in the AC direction (p=0.004), while the WC direction resulted only in 5% increase (from 491 to 516.5 kPa, respectively--not significant) in leaflet stiffness in the active state. Also, the loss of basal tonus of the AVIC population with thapsigargin treatment resulted in 76% (AC, p=0.001) and 54% (WC, p=0.036) decreases in leaflet stiffness at 5 mM KCl levels, while preventing contraction with the addition of 90 mM KCl as expected. We speculate that the observed layer dependent effects of AVIC contraction are primarily due to varying ECM mechanical properties in the ventricularis and fibrosa layers. Moreover, while we have demonstrated that AVIC contractile ability is a significant contributor to AV leaflet bending stiffness, it most likely serves a role in maintaining AV leaflet tissue homeostasis that has yet to be elucidated.
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Affiliation(s)
- W David Merryman
- Engineered Tissue Mechanics Laboratory, Department of Bioengineering, and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA 15219, USA
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Lacefield JC, Weaver J, Spence JR, Dunmore-Buyze J, Boughner DR. Three-dimensional visualization and thickness estimation of aortic valve cusps using high-frequency ultrasound. Physiol Meas 2003; 25:27-36. [PMID: 15005302 DOI: 10.1088/0967-3334/25/1/003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
High-frequency ultrasound techniques are introduced for three-dimensional imaging and thickness estimation of fresh heart valve cusps. Images of porcine aortic valve specimens were acquired within a 12 x 8 x 8 mm3 volume using a VisualSonics VS40 micro-imaging system operating at a 40 MHz centre frequency. Two image volumes were obtained from each of six left coronary cusps. One volume was acquired with the specimen submerged in distilled water and the second volume was acquired through either Hanks physiologic solution or coronary perfusion solution (CPS). The fibrosa, spongiosa and ventricularis were most readily distinguished when the specimen was imaged in distilled water. Colour thickness maps were computed from B-mode image data, and the mean and standard deviations of the thickness were determined for each cusp. In 11 of 12 trials, the image analysis algorithm yielded valid thickness estimates over greater than 98% of the region examined. Mean thickness estimates obtained with specimens submerged in Hanks solution or CPS ranged from 0.66 to 1.03 mm, and submersion in distilled water increased the mean thickness by 20-40%. This observation suggests that the cusps osmotically absorbed water. Information provided by high-frequency ultrasound is expected be valuable for characterizing the morphological properties of heart valves.
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Affiliation(s)
- James C Lacefield
- Department of Electrical and Computer Engineering, University of Western Ontario, 3002 Engineering Building, London, ON N6A 5B9, Canada.
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Response to the letter to the Editor. Cardiovasc Pathol 2003. [DOI: 10.1016/s1054-8807(03)00040-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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McDonald PC, Wilson JE, Gao M, McNeill S, Spinelli JJ, Williams OD, Harji S, Kenyon J, McManus BM. Quantitative analysis of human heart valves: does anorexigen exposure produce a distinctive morphological lesion? Cardiovasc Pathol 2002; 11:251-62. [PMID: 12361835 DOI: 10.1016/s1054-8807(02)00110-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The need for more detail regarding the clinical and morphological features of human heart valves has become evident due to recent controversy regarding anorexigen-associated valvular dysfunction. In the present study, we used quantitative digital image analysis of geometric and compositional features to compare the histopathology of cardiac valves excised from patients treated with anorexigens as compared to normal, floppy, rheumatic and carcinoid valves. Anorexigen-exposed valves had the greatest number of onlays/valve (P<.0001), while rheumatic valves showed the greatest average onlay size and thickness of the comparison groups studied (P=.01). The valve onlays from anorexigen-exposed, carcinoid and floppy valves contained a greater percentage of glycosaminoglycans (GAGs) as compared to normal and rheumatic valves (P=.01). The anorexigen-exposed valve propers contained more GAGs than any other comparison group (P=.02). Vessels were prominent in both onlay and valve proper regions of carcinoid valves, in the anorexigen-exposed valve onlays and in rheumatic valve propers. Thus, the number of onlays, their size, the degree of GAG deposition, and the presence and location of vessels and leukocytes were important features distinguishing anorexigen-exposed valves from normal valves. Discriminant analyses, based on geometry, color composition or color composition, and vessel and leukocyte counts combined, were able to separate the valves into distinguishable groups. Our findings demonstrate that specific microscopic features can be used to separate anorexigen-associated heart valve lesions from normal valves and valve lesions associated with other pathologies, and suggest that a distinctive pathological process may exist in many anorexigen-exposed valves.
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Affiliation(s)
- Paul C McDonald
- University of British Columbia, McDonald Research Laboratories, Room 292, 1081 Burrard Street, Vancouver, BC, Canada, V6Z1Y6
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