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Arterial Circulation

The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform

Thomas Gries – 1st expert on this subject based on the ideXlab platform

  • fibrin polylactide based tissue engineered vascular graft in the Arterial Circulation
    Biomaterials, 2010
    Co-Authors: Sabine Koch, Thomas C Flanagan, Joerg S Sachweh, Fadwa Tanios, Heike Schnoering, Thorsten Deichmann, Ville Ella, Minna Kellomaki, Nina Gronloh, Thomas Gries

    Abstract:

    There is a clear clinical requirement for the design and development of living, functional, small-calibre Arterial grafts. Here, we investigate the potential use of a small diameter, tissue-engineered artery in a pre-clinical study in the carotid artery position of sheep. Small-calibre (∼5 mm) vascular composite grafts were molded using a fibrin scaffold supported by a poly(L/D)lactide 96/4 (P(L/D)LA 96/4) mesh, and seeded with autologous Arterial-derived cells prior to 28 days of dynamic conditioning. Conditioned grafts were subsequently implanted for up to 6 months as interposed carotid artery grafts in the same animals from which the cells were harvested. Explanted grafts (n = 6) were patent in each of the study groups (1 month, 3 months, 6 months), with a significant stenosis in one explant (3 months). There was a complete absence of thrombus formation on the luminal surface of grafts, with no evidence for aneurysm formation or calcification after 6 months in vivo. Histological analyses revealed remodeling of the fibrin scaffold with mature autologous proteins, and excellent cell distribution within the graft wall. Positive vWf and eNOS staining, in addition to scanning electron microscopy, revealed a confluent monolayer of endothelial cells lining the luminal surface of the grafts. The present study demonstrates the successful production and mid-term application of an autologous, fibrin-based small-calibre vascular graft in the Arterial Circulation, and highlights the potential for the creation of autologous implantable Arterial grafts in a number of settings.

Wei Wu – 2nd expert on this subject based on the ideXlab platform

  • appropriate density of pcl nano fiber sheath promoted muscular remodeling of pgs pcl grafts in Arterial Circulation
    Biomaterials, 2016
    Co-Authors: Xin Yang, Wei Wu

    Abstract:

    Abstract Cell-free approach represents a philosophical shift from the prevailing focus on cells in vascular tissue engineering. Porous elastomeric grafts made of poly(glycerol sebacate) (PGS) enforced with polycaprolactone (PCL) nano-fibers degrade rapidly and yield neoarteries nearly free of foreign materials in rat abdominal aorta. However, considering the larger variation of blood pressure and slower host remodeling in human body than in rat, it is important to investigate the in vivo performance of PGS-PCL graft with enhanced mechanical properties, so that optimized Arterial grafts could be developed for clinical translation. We acquired increasingly compacted sheath by prolonging the electrospinning period of PCL appropriately, which significantly enforced whole grafts. The rational design of sheath density significantly decreased the risk of dilation, rupture as well as enabling the long-term muscular remodeling. Since 3–12 months after implantation, the PGS grafts with rationally strengthened sheath were remodeled into neoarteries resembled native arteries in the following aspects: high patency rate and even vessel wall thickness; a confluent endothelium and contractile smooth muscle layers; expression of elastin, collagen and glycosaminoglycan; tough and compliant mechanical properties. Although loose sheath may result in rupture of vessel wall, adequate porosity was proved to be essential for sheath structure and directly determined muscular remodeling through M2 macrophage involved constructive remodeling. Therefore, this study confirmed that adequate density of PCL sheath in PGS grafts could initiate stable and high-quality muscular remodeling, which contributes to long-term success in Arterial Circulation before clinical translation.

  • Appropriate density of PCL nano-fiber sheath promoted muscular remodeling of PGS/PCL grafts in Arterial Circulation.
    Biomaterials, 2016
    Co-Authors: Xin Yang, Wei Wu

    Abstract:

    Abstract Cell-free approach represents a philosophical shift from the prevailing focus on cells in vascular tissue engineering. Porous elastomeric grafts made of poly(glycerol sebacate) (PGS) enforced with polycaprolactone (PCL) nano-fibers degrade rapidly and yield neoarteries nearly free of foreign materials in rat abdominal aorta. However, considering the larger variation of blood pressure and slower host remodeling in human body than in rat, it is important to investigate the in vivo performance of PGS-PCL graft with enhanced mechanical properties, so that optimized Arterial grafts could be developed for clinical translation. We acquired increasingly compacted sheath by prolonging the electrospinning period of PCL appropriately, which significantly enforced whole grafts. The rational design of sheath density significantly decreased the risk of dilation, rupture as well as enabling the long-term muscular remodeling. Since 3–12 months after implantation, the PGS grafts with rationally strengthened sheath were remodeled into neoarteries resembled native arteries in the following aspects: high patency rate and even vessel wall thickness; a confluent endothelium and contractile smooth muscle layers; expression of elastin, collagen and glycosaminoglycan; tough and compliant mechanical properties. Although loose sheath may result in rupture of vessel wall, adequate porosity was proved to be essential for sheath structure and directly determined muscular remodeling through M2 macrophage involved constructive remodeling. Therefore, this study confirmed that adequate density of PCL sheath in PGS grafts could initiate stable and high-quality muscular remodeling, which contributes to long-term success in Arterial Circulation before clinical translation.

Christopher K Breuer – 3rd expert on this subject based on the ideXlab platform

  • characterization of evolving biomechanical properties of tissue engineered vascular grafts in the Arterial Circulation
    Journal of Biomechanics, 2014
    Co-Authors: Brooks V Udelsman, Ramak Khosravi, Kristin S Miller, Ethan W Dean, Matthew R Bersi, Kevin A Rocco, Tai Yi, Jay D Humphrey, Christopher K Breuer

    Abstract:

    Abstract We used a murine model to assess the evolving biomechanical properties of tissue engineered vascular grafts (TEVGs) implanted in the Arterial Circulation. The initial polymeric tubular scaffold was fabricated from poly(lactic acid)(PLA) and coated with a 50:50 copolymer of poly(caprolactone) and poly(lactic acid)(P[PC/LA]). Following seeding with syngeneic bone marrow derived mononuclear cells, TEVGs (n=50) were implanted as aortic interposition grafts in wild-type mice and monitored serially using ultrasound. A custom biaxial mechanical testing device was used to quantify the in vitro circumferential and axial mechanical properties of grafts explanted at 3 or 7 months. At both times, TEVGs were much stiffer than native tissue in both directions. Repeated mechanical testing of some TEVGs treated with elastase or collagenase suggested that elastin did not contribute significantly to the overall stiffness whereas collagen did contribute. Traditional histology and immunostaining revealed smooth muscle cell layers, significant collagen deposition, and increasing elastin production in addition to considerable scaffold at both 3 and 7 months, which likely dominated the high stiffness seen in mechanical testing. These results suggest that PLA has inadequate in vivo degradation, which impairs cell-mediated development of vascular neotissue having properties closer to native arteries. Assessing contributions of individual components, such as elastin and collagen, to the developing neovessel is needed to guide computational modeling that may help to optimize the design of the TEVG.