Patricia M Taylor

Imperial College London, London, ENG, United Kingdom

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Publications (26)98.26 Total impact

  • Journal of Molecular and Cellular Cardiology - J MOL CELL CARDIOL. 01/2006; 40(6):1014-1015.
  • Journal of Molecular and Cellular Cardiology - J MOL CELL CARDIOL. 01/2006; 40(6):947-947.
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    ABSTRACT: The pattern of expression and distribution of extracellular matrix (ECM) components in human cardiac leaflets was analyzed. Additionally, interstitial cells (ICs) from the four different leaflets were isolated and studied. Immunohistochemistry and immunocytochemistry were used for localization, and flow cytometric analysis to quantify the expression of specific markers on these ICs; the synthesis and expression of ECM components was assessed. Elastin was found predominantly on the inflow layer, but fine fibers were also present in the central and outflow layers. Collagen I was predominantly on the outflow layer but permeated throughout the leaflets. Collagen III was expressed ubiquitously. Proteoglycan expression was throughout the leaflet, but was predominant in the central layer. Fibronectin and vitronectin were expressed strongly in the inflow layer, moderately in the central layer, and weakly in the outflow layer. Biglycan expression was ubiquitous, with strong filamentous strands in the central layer. Keratan sulfate and decorin were ubiquitous. Chondroitin-4-sulfate and chondroitin-6-sulfate were strongly expressed in the outer layers, and laminin was restricted to the basal lamina of the endothelial cells. Cultured ICs showed synthesis and expression of various ECM components. This study of the pattern of expression of ECM components may provide a basis for a fingerprint on which to base future valve alternatives. The results provide useful information for valve tissue engineering and an understanding of the structural basis of some sophisticated functions of the valves.
    The Journal of heart valve disease 04/2005; 14(2):218-27. · 1.07 Impact Factor
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    ABSTRACT: Cardiac valve interstitial cells (ICs) are a heterogeneous and dynamic population of specific cell types that have many unique characteristics. They are responsible for maintaining the extracellular scaffold that provides the mechanical characteristics vital for sustaining the unique dynamic behaviour of the valve. A number of cellular phenotypes can be distinguished: some are sparsely arranged throughout the valve leaflets, whilst others are arranged in thin bundles. These cells express molecular markers similar to those of skeletal, cardiac and smooth muscle cells (SMCs) and in particular, many ICs express smooth muscle (SM) alpha-actin, a marker of myofibroblasts. In this respect, these cells exhibit a profile unlike skin fibroblasts, which may allude to their role in valve function.
    The International Journal of Biochemistry & Cell Biology 03/2003; 35(2):113-8. · 4.15 Impact Factor
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    ABSTRACT: Tissue turnover is one of many factors involved in the operational longevity of heart valves. An understanding of how valves remodel their matrix in response to the hemodynamic environment in health and disease is crucial to the design and biological responsiveness of tissue-engineered valve substitutes. Matrix metalloproteinases (MMPs) are proteolytic enzymes involved in matrix remodeling in several tissues, and include interstitial collagenase (MMP-1, MMP-13), the gelatinases (MMP-2, MMP-9) and stromelysin (MMP-3). Expression of MMPs and their tissue inhibitors (TIMPs) in human aortic, mitral, tricuspid and pulmonary valves from unused donor or transplant recipient hearts was determined by immunohistochemical staining using antibodies against human MMP-1, MMP-2, MMP-3 and MMP-9 and their inhibitors TIMP-1, TIMP-2, TIMP-3. Cell identification was achieved using antibodies against CD31(endothelial cells), smooth muscle alpha-actin (microfilaments) and CD68 (macrophages). MMP-1 was expressed in all valves, whereas MMP-2 was only expressed in aortic and pulmonary leaflets. MMP-3 and MMP-9 were not expressed. TIMP-1 and TIMP-2 were expressed in all leaflets, whereas TIMP-3 was observed only in tricuspid leaflets. Valves have a specific pattern of expression of MMPs and TIMPs, which appears to vary in different heart valves. The functional implications and central mechanisms responsible require further study. These findings have important implications in understanding the dynamic nature of valve remodeling and in aiding the development of tissue-engineered valves.
    The Journal of heart valve disease 12/2002; 11(6):875-80; discussion 880. · 1.07 Impact Factor
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    ABSTRACT: The use of a biological, biodegradable scaffold remodeled by cells to resemble a valve leaflet is an attractive approach to tissue engineering. The study aim was to evaluate the suitability of a three-dimensional biodegradable collagen sponge for maintenance of cell viability, proliferation and phenotype of cultured human cardiac valve interstitial cells (ICs). Pieces of valve leaflets were snap-frozen, sectioned and stained by immunoperoxidase. Interstitial cells were cultured from cardiac valves and plated onto glass coverslips or seeded in collagen sponge, then stained by immunofluorescence or immunoperoxidase. A panel of antibodies was used to determine cell phenotype. Cell viability was assessed using a dye-based cell proliferation assay, and cell death by lactate dehydrogenase measurement. ICs variably expressing the phenotypic markers were found throughout the native valve leaflet, but particularly on the ventricular side. Cultured ICs either on coverslips or in collagen sponge expressed vimentin, a fibroblast surface antigen and variable amounts of smooth muscle (SM) alpha-actin. Expression of the other phenotypic markers, SM myosin, desmin and prolyl 4-hydroxylase differed: interestingly, the ratio of cells in collagen sponge expressing these markers reflected that found in the native valve leaflet. Confocal microscopy of ICs in the collagen sponge revealed the presence of cells with long interconnecting extensions indicating cell communication. Cell proliferation and cell death assays established that cells were not only viable after four weeks in the sponge, but were also proliferating. This study demonstrates that collagen sponge is a suitable biodegradable scaffold that can maintain viable valve ICs and appears to enhance the capacity of the cell to express its original phenotype.
    The Journal of heart valve disease 06/2002; 11(3):298-306; discussion 306-7. · 1.07 Impact Factor

Publication Stats

675 Citations
98.26 Total Impact Points

Institutions

  • 2005–2012
    • Imperial College London
      • • Institute of Biomedical Engineering (IBME)
      • • Cardiovascular Sciences
      London, ENG, United Kingdom
  • 2010
    • I.R.C.C.S. Policlinico San Donato
      Milano, Lombardy, Italy
  • 2007–2010
    • The Heart Lung Center
      Londinium, England, United Kingdom
  • 2002–2007
    • National Heart, Lung, and Blood Institute
      Maryland, United States