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Uiterwijk M, Coolen B, Rijswijk van JW, Söntjens S, van Houtem M, Szymczyk W, Rijns L, Janssen H, Wal van der A, Mol de B, Bouten C, Strijkers G, Dankers P, Kluin J. BALANCING SCAFFOLD DEGRADATION AND NEO-TISSUE FORMATION IN IN-SITU TISSUE ENGINEERED VASCULAR GRAFTS. Tissue Eng Part A 2024. [PMID: 38420632 DOI: 10.1089/ten.tea.2023.0019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024] Open
Abstract
An essential aspect of cardiovascular in situ tissue engineering (TE) is to ensure balance between scaffold degradation and neo-tissue formation. We evaluated the degradation velocity and neo-tissue formation of three electrospun supramolecular bisurea-based biodegradable scaffolds that differ in their soft-block backbone compositions only. Scaffolds were implanted as interposition grafts in the abdominal aorta in rats, and evaluated at different time points (t = 1, 6, 12, 24 and 40 weeks) on function, tissue formation, strength and scaffold degradation. The fully carbonate-based biomaterial showed minor degradation after 40 weeks in vivo, while the other two ester-containing biomaterials showed (near) complete degradation within 6 to 12 weeks. Local dilatation was only observed in these faster degrading scaffolds. All materials showed to some extent calcifications, at early as well as late time points. Histological evaluation showed equal and non-native like neo-tissue formation after total degradation. The fully carbonate based scaffolds lagged in neo-tissue formation, presumably as its degradation was (far from) complete at 40 weeks. A significant difference in vessel wall contrast enhancement was observed by MRI between grafts with total compared to minimal degraded scaffolds.
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Affiliation(s)
- Marcelle Uiterwijk
- Amsterdam UMC Location AMC, 26066, Cardiothoracic surgery, Meibergdreef 9, Amsterdam, Netherlands, 1105 AZ;
| | - Bram Coolen
- Amsterdam UMC Locatie AMC, 26066, Department of Biomedical Engineering & Physics, Amsterdam, Netherlands;
| | | | - Serge Söntjens
- Eindhoven University of Technology, 3169, Symochem b.v., Eindhoven, Netherlands;
| | - Michel van Houtem
- Eindhoven University of Technology, 3169, Symochem b.v. , Eindhoven, Netherlands;
| | - Wojciech Szymczyk
- Eindhoven University of Technology, 3169, Department of Biomedical Engineering, Eindhoven, Netherlands;
| | - Laura Rijns
- Eindhoven University of Technology, 3169, Biomedical Engineering, Eindhoven, Netherlands
- Eindhoven University of Technology, 3169, Institute for Complex Molecular Systems, Eindhoven, Netherlands;
| | - Henk Janssen
- Eindhoven University of Technology, 3169, Symochem b.v. , Eindhoven, Noord-Brabant, Netherlands;
| | | | - Bas Mol de
- Amsterdam UMC Location AMC, 26066, Cardiothoracic surgery, Amsterdam, Netherlands;
| | - Carlijn Bouten
- Eindhoven University of Technology, 3169, Biomedical Engineering, Eindhoven, Netherlands
- Eindhoven University of Technology, 3169, Institute for Complex Molecular Systems, Eindhoven, Netherlands;
| | - Gustav Strijkers
- Amsterdam UMC Locatie AMC, 26066, Biomedical Engineering and Physics, Amsterdam, Netherlands;
| | - Patricia Dankers
- Eindhoven University of Technology, 3169, Biomedical Engineering, Eindhoven, Netherlands
- Eindhoven University of Technology, 3169, Institute for Complex Molecular Systems, Eindhoven, Netherlands;
| | - Jolanda Kluin
- Erasmus Medical Center, 6993, Cardiothoracic surgery, Rotterdam, Netherlands;
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2
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Jansen I, Crielaard H, Wissing T, Bouten C, Gijsen F, Akyildiz AC, Farrell E, van der Heiden K. A tissue-engineered model of the atherosclerotic plaque cap: Toward understanding the role of microcalcifications in plaque rupture. APL Bioeng 2023; 7:036120. [PMID: 37786532 PMCID: PMC10541963 DOI: 10.1063/5.0168087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 09/18/2023] [Indexed: 10/04/2023] Open
Abstract
Rupture of the cap of an atherosclerotic plaque can lead to thrombotic cardiovascular events. It has been suggested, through computational models, that the presence of microcalcifications in the atherosclerotic cap can increase the risk of cap rupture. However, the experimental confirmation of this hypothesis is still lacking. In this study, we have developed a novel tissue-engineered model to mimic the atherosclerotic fibrous cap with microcalcifications and assess the impact of microcalcifications on cap mechanics. First, human carotid plaque caps were analyzed to determine the distribution, size, and density of microcalcifications in real cap tissue. Hydroxyapatite particles with features similar to real cap microcalcifications were used as microcalcification mimics. Injected clusters of hydroxyapatite particles were embedded in a fibrin gel seeded with human myofibroblasts which deposited a native-like collagenous matrix around the particles, during the 21-day culture period. Second harmonic multiphoton microscopy imaging revealed higher local collagen fiber dispersion in regions of hydroxyapatite clusters. Tissue-engineered caps with hydroxyapatite particles demonstrated lower stiffness and ultimate tensile stress than the control group samples under uniaxial tensile loading, suggesting increased rupture risk in atherosclerotic plaques with microcalcifications. This model supports previous computational findings regarding a detrimental role for microcalcifications in cap rupture risk and can further be deployed to elucidate tissue mechanics in pathologies with calcifying soft tissues.
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Affiliation(s)
- Imke Jansen
- Department of Biomedical Engineering, Thorax Center Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Hanneke Crielaard
- Department of Biomedical Engineering, Thorax Center Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Tamar Wissing
- Department of Biomedical Engineering, Thorax Center Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | | | | | | | - Eric Farrell
- Department of Oral and Maxillofacial Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Kim van der Heiden
- Department of Biomedical Engineering, Thorax Center Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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3
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Koch SE, Verhaegh FLP, Smink S, Mihăilă SM, Bouten C, Smits A. Donor Heterogeneity in the Human Macrophage Response to a Biomaterial under Hyperglycemia in vitro. Tissue Eng Part C Methods 2022; 28:440-456. [PMID: 35658619 DOI: 10.1089/ten.tec.2022.0066] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Macrophages have a commanding role in scaffold-driven in situ tissue regeneration. Depending on their polarization state, macrophages mediate the formation and remodeling of new tissue by secreting growth factors and cytokines. Therefore, successful outcomes of material-driven in situ tissue vascular tissue engineering depends largely on the immuno-regenerative potential of the recipient. A large cohort of patients requiring vascular replacements suffers from systemic multifactorial diseases, like diabetes, which gives rise to a hyperglycemic and aggressive oxidative inflammatory environment that is hypothesized to hamper a well-balanced regenerative process. Here, we aimed to fundamentally explore the effects of hyperglycemia, as one of the hallmarks of diabetes, on the macrophage response to 3D electrospun synthetic biomaterials for in situ tissue engineering, in terms of inflammatory profile and tissue regenerative capacity. To simulate the early phases of the in situ regenerative cascade, we used a bottom-up in vitro approach. Primary human macrophages (n=8 donors) and (myo)fibroblasts in mono- or co-culture were seeded in 2D, as well as in a 3D electrospun resorbable polycaprolactone bisurea (PCL-BU) scaffold and exposed to normoglycemic (5.5 mM glucose), hyperglycemic (25 mM glucose) and osmotic control conditions (5.5 mM glucose, 19.5 mM mannitol). The results showed that macrophage polarization by biochemical stimuli was effective under all glycemic conditions and that the polarization states dictated expression of the receptors SCL2A1 (glucose transporter 1) and CD36 (fatty acid transporter). In 3D, the macrophage response to hyperglycemic conditions was strongly donor-dependent in terms of phenotype, cytokine secretion profile, and metabolic receptor expression. When co-cultured with (myo)fibroblasts, hyperglycemic conditions led to an increased expression of fibrogenic markers (ACTA2, COL1, COL3, IL-1β). Together, these findings show that the hyperglycemic and hyperosmotic conditions may indeed influence the process of macrophage-driven in situ tissue engineering, and that the extent of this is likely to be patient-specific.
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Affiliation(s)
- Suzanne E Koch
- Eindhoven Univeristy of Technology, Department of Biomedical Engineering, Eindhoven, Netherlands;
| | - Franka L P Verhaegh
- Eindhoven Univeristy of Technology, Department of Biomedical Engineering, Eindhoven, Netherlands;
| | - Simone Smink
- Eindhoven Univeristy of Technology, Department of Biomedical Engineering, Eindhoven, Netherlands;
| | - Silvia M Mihăilă
- Utrecht University Department of Pharmaceutical Sciences, 84898, Utrecht, Utrecht, Netherlands;
| | - Carlijn Bouten
- Eindhoven University of Technology, Biomedical Engineering, Eindhoven University of Technology, Department of Biomedical Engineering, P.O.Box 513, Eindhoven, Netherlands, 5600MB.,Netherlands;
| | - Anthal Smits
- Eindhoven Univeristy of Technology, Department of Biomedical Engineering, Den Dolech 2, Gemini-Zuid 3.116, Eindhoven, Netherlands, 5612AZ;
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Schenk P, Inderson A, Bouten C, Rotteveel W, Didden J, Buurman S, Cobbaert C. W271 Creatinine and kidney function in icteric patients – Automated reflex protocol including cystatin C. Clin Chim Acta 2022. [DOI: 10.1016/j.cca.2022.04.397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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5
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Driessen R, Zhao F, Hofmann S, Bouten C, Sahlgren C, Stassen O. Computational Characterization of The Dish-In-A-Dish, A High Yield Culture Platform for Endothelial Shear Stress Studies on the Orbital Shaker. Micromachines (Basel) 2020; 11:mi11060552. [PMID: 32486105 PMCID: PMC7345652 DOI: 10.3390/mi11060552] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/25/2020] [Accepted: 05/27/2020] [Indexed: 12/18/2022]
Abstract
Endothelial cells sense and respond to shear stress. Different in vitro model systems have been used to study the cellular responses to shear stress, but these platforms do not allow studies on high numbers of cells under uniform and controllable shear stress. The annular dish, or dish-in-a-dish (DiaD), on the orbital shaker has been proposed as an accessible system to overcome these challenges. However, the influence of the DiaD design and the experimental parameters on the shear stress patterns is not known. In this study, we characterize different designs and experimental parameters (orbit size, speed and fluid height) using computational fluid dynamics. We optimize the DiaD for an atheroprotective flow, combining high shear stress levels with a low oscillatory shear index (OSI). We find that orbit size determines the DiaD design and parameters. The shear stress levels increase with increasing rotational speed and fluid height. Based on our optimization, we experimentally compare the 134/56 DiaD with regular dishes for cellular alignment and KLF2, eNOS, CDH2 and MCP1 expression. The calculated OSI has a strong impact on alignment and gene expression, emphasizing the importance of characterizing shear profiles in orbital setups.
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Affiliation(s)
- Rob Driessen
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; (R.D.); (F.Z.); (S.H.); (C.B.); (C.S.)
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Feihu Zhao
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; (R.D.); (F.Z.); (S.H.); (C.B.); (C.S.)
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Zienkiewicz Centre for Computational Engineering, College of Engineering, Swansea University, Swansea SA1 8EN, UK
| | - Sandra Hofmann
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; (R.D.); (F.Z.); (S.H.); (C.B.); (C.S.)
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Carlijn Bouten
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; (R.D.); (F.Z.); (S.H.); (C.B.); (C.S.)
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Cecilia Sahlgren
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; (R.D.); (F.Z.); (S.H.); (C.B.); (C.S.)
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Faculty of Science and Engineering, Biosciences, Åbo Akademi University, 20500 Turku, Finland
- Turku Bioscience Centre, Åbo Akademi University and University of Turku, 20520 Turku, Finland
| | - Oscar Stassen
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; (R.D.); (F.Z.); (S.H.); (C.B.); (C.S.)
- Faculty of Science and Engineering, Biosciences, Åbo Akademi University, 20500 Turku, Finland
- Turku Bioscience Centre, Åbo Akademi University and University of Turku, 20520 Turku, Finland
- Correspondence: or
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6
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Hutcheson JD, Goettsch C, Bertazzo S, Maldonado N, Ruiz JL, Goh W, Yabusaki K, Faits T, Bouten C, Franck G, Quillard T, Libby P, Aikawa M, Weinbaum S, Aikawa E. Genesis and growth of extracellular-vesicle-derived microcalcification in atherosclerotic plaques. Nat Mater 2016; 15:335-43. [PMID: 26752654 PMCID: PMC4767675 DOI: 10.1038/nmat4519] [Citation(s) in RCA: 254] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 11/24/2015] [Indexed: 05/26/2023]
Abstract
Clinical evidence links arterial calcification and cardiovascular risk. Finite-element modelling of the stress distribution within atherosclerotic plaques has suggested that subcellular microcalcifications in the fibrous cap may promote material failure of the plaque, but that large calcifications can stabilize it. Yet the physicochemical mechanisms underlying such mineral formation and growth in atheromata remain unknown. Here, by using three-dimensional collagen hydrogels that mimic structural features of the atherosclerotic fibrous cap, and high-resolution microscopic and spectroscopic analyses of both the hydrogels and of calcified human plaques, we demonstrate that calcific mineral formation and maturation results from a series of events involving the aggregation of calcifying extracellular vesicles, and the formation of microcalcifications and ultimately large calcification areas. We also show that calcification morphology and the plaque's collagen content-two determinants of atherosclerotic plaque stability-are interlinked.
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Affiliation(s)
- Joshua D. Hutcheson
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Claudia Goettsch
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Sergio Bertazzo
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
| | - Natalia Maldonado
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Jessica L. Ruiz
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Wilson Goh
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Katsumi Yabusaki
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Tyler Faits
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Carlijn Bouten
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Gregory Franck
- Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Thibaut Quillard
- Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Peter Libby
- Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Masanori Aikawa
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
- Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Sheldon Weinbaum
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Elena Aikawa
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
- Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
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7
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MacGrogan D, Luxán G, Driessen-Mol A, Bouten C, Baaijens F, de la Pompa JL. How to make a heart valve: from embryonic development to bioengineering of living valve substitutes. Cold Spring Harb Perspect Med 2014; 4:a013912. [PMID: 25368013 DOI: 10.1101/cshperspect.a013912] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Cardiac valve disease is a significant cause of ill health and death worldwide, and valve replacement remains one of the most common cardiac interventions in high-income economies. Despite major advances in surgical treatment, long-term therapy remains inadequate because none of the current valve substitutes have the potential for remodeling, regeneration, and growth of native structures. Valve development is coordinated by a complex interplay of signaling pathways and environmental cues that cause disease when perturbed. Cardiac valves develop from endocardial cushions that become populated by valve precursor mesenchyme formed by an epithelial-mesenchymal transition (EMT). The mesenchymal precursors, subsequently, undergo directed growth, characterized by cellular compartmentalization and layering of a structured extracellular matrix (ECM). Knowledge gained from research into the development of cardiac valves is driving exploration into valve biomechanics and tissue engineering directed at creating novel valve substitutes endowed with native form and function.
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Affiliation(s)
- Donal MacGrogan
- Program of Cardiovascular Developmental Biology, Department of Cardiovascular Development and Repair, Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Guillermo Luxán
- Program of Cardiovascular Developmental Biology, Department of Cardiovascular Development and Repair, Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Anita Driessen-Mol
- Biomedical Engineering/Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Carlijn Bouten
- Biomedical Engineering/Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Frank Baaijens
- Biomedical Engineering/Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - José Luis de la Pompa
- Program of Cardiovascular Developmental Biology, Department of Cardiovascular Development and Repair, Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
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Bernaert N, Van Droogenbroeck B, Bouten C, De Paepe D, Van Bockstaele E, De Clercq H, Stewart D, De Loose M. The antioxidant capacity of leek (Allium ampeloprasum var. porrum). Commun Agric Appl Biol Sci 2011; 76:173-176. [PMID: 21539224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- N Bernaert
- Department of Plant Production, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
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9
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Baaijens F, Bouten C, Hoerstrup S, Mol A, Driessen N, Boerboom R. Functional tissue engineering of the aortic heart valve. Clin Hemorheol Microcirc 2005; 33:197-9. [PMID: 16215285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- Frank Baaijens
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
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Delhaas T, Van Engeland S, Broers J, Bouten C, Kuijpers N, Ramaekers F, Snoeckx LHEH. Quantification of cytoskeletal deformation in living cells based on hierarchical feature vector matching. Am J Physiol Cell Physiol 2002; 283:C639-45. [PMID: 12107074 DOI: 10.1152/ajpcell.00535.2001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The cytoskeleton is a dynamic scaffold in living cells even in the absence of externally imposed forces. In this study on cytoskeletal deformation, the applicability of hierarchical feature vector matching (HFVM), a new matching method, currently applied in space research and three-dimensional surface reconstruction, was investigated. Stably transfected CHO-K1 cells expressing green fluorescent protein (GFP) coupled to vimentin were used to visualize spontaneous movement of the vimentin cytoskeleton of individual cells using a confocal laser scanning system. We showed that, with proper parameter and configuration settings, HFVM could recognize and trace 60-70% of all image points in artificially translated, rotated, or deformed images. If only points belonging to the cytoskeleton were selected for matching purposes, the percentage of matched points increased to 98%. This high percentage of recognition also could be reached in a time series of images, in which a certain degree of bleaching of the fluorescence over the recording time of 30 min was inevitable. In these images, HFVM allowed the detection as well as the quantification of spontaneous cytoskeletal movements of up to 10% of the cell width. Therefore, HFVM appears to be a reliable method of quantifying dynamic cytoskeletal behavior in living cells.
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Affiliation(s)
- Tammo Delhaas
- Department of Physiology, Cardiovascular Research Institute, Maastricht University, University Hospital Maastricht, The Netherlands.
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Abstract
OBJECTIVE To give a descriptive analysis of aerobic capacity among elite wheelchair athletes in association with various personal characteristics and sprint or anaerobic capacity. DESIGN Sixty-eight wheelchair athletes who participated in the World Games and Championships for the Disabled were included. Parameters for aerobic capacity were evaluated in a standardized wheelchair exercise test on a computer-controlled wheelchair ergometer at the games. The ergometer setting was individually tuned according to standardized procedures. RESULTS Mean maximum power output was 72.2 +/- 36.7 W. Peak oxygen uptake showed similar strong variations among different subject groups. High values were seen in a group of six subjects with amputations. Results stressed that, apart from sex, functionality and training status had a strong influence on aerobic capacity. Anaerobic and aerobic capacity were strongly associated. CONCLUSIONS Functionality, training status, and sex are important determinants of aerobic capacity. The functional classification used at international sports events is represented in the data, and further study into the possible contribution of standardized exercise tests within the issue of classification must be considered. The use of standardized exercise tests for the evaluation of training and for rehabilitation progress must be advocated, with power output being an important outcome measure at the level of ability, whereas oxygen uptake represents outcome at the level of organ systems.
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Affiliation(s)
- L H V van der Woude
- Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
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