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Dietrich E Birnbaum - One of the best experts on this subject based on the ideXlab platform.
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development of endothelium denuded human Umbilical Veins as living scaffolds for tissue engineered small calibre vascular grafts
Journal of Tissue Engineering and Regenerative Medicine, 2013Co-Authors: Markus Hoenicka, Siegfried Schrammel, Georgine Huber, Christof Schmid, Jiri Bursa, Holger Bronger, Dietrich E BirnbaumAbstract:Tissue-engineered small-calibre vessel grafts may help to alleviate the lack of graft material for coronary and peripheral bypass grafting in an increasing number of patients. This study explored the use of endotheliumdenuded human Umbilical Veins (HUVs) as scaffolds for vascular tissue engineering in a perfusion bioreactor. Vessel diameter (1.2 � 0.4mm), wall thickness (0.38 � 0.09mm), uniaxial ultimate failure stress (8029 � 1714 kPa) and burst pressure (48.4 � 20.2 kPa, range 28.4–83.9 kPa) were determined in native samples. The effects of endothelium removal from HUVs by enzymatic digestion, hypotonic lysis and dehydration were assessed. Dehydration did not significantly affect contractile function, tetrazolium dye reduction, mechanical strength and vesselstructure,whereas the other methods failed in at leastone of these parameters. Denudation by dehydration retained laminin, fibronectin, collagen and elastic fibres. Denuded HUVs were seeded in a perfusion bioreactor with either allogeneic HUVs endothelial cells or with saphenous vein endothelial cells harvested from patients with coronary artery disease. Seeding in a perfusion bioreactor resulted in a confluent monolayer of endothelial cells from both sources, as judged by histology and scanning electron microscopy. Seeded cells contained von Willebrand factor and CD31. In conclusion, denuded HUVs should be considered an alternative to decellularized blood vessels, as the process keeps the smooth muscle layer intact and functional, retains proteins relevant for biomechanic properties and for cell attachment and provides a suitable scaffold for seeding an autologous and flow-resistant endothelium. Copyright © 2012 John Wiley & Sons, Ltd.
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tissue engineering of small caliber vessel grafts from human Umbilical Veins
2009Co-Authors: Markus Hoenicka, Siegfried Schrammel, Volker R Jacobs, Georgine Huber, Christof Schmid, Dietrich E BirnbaumAbstract:Human Umbilical Veins (HUV) have recently been suggested as a starting material for vascular tissue engineering. HUV possess a functional smooth muscle layer and could be turned into an immunologically inert graft with contractile properties by creating a neoendothelium from the recipient’s own cells. This study investigated methods to remove the native endothelium without impairing the contractile function of the smooth muscle layer. These denuded HUV were then seeded with endothelial cells in a perfusion bioreactor, demonstrating the creation of a confluent, shear-resistant neoendothelium.
Leonard W Seymour - One of the best experts on this subject based on the ideXlab platform.
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use of a phage display library to identify oligopeptides binding to the lumenal surface of polarized endothelium by ex vivo perfusion of human Umbilical Veins
Journal of Drug Targeting, 2003Co-Authors: Fukuto Maruta, Alan L Parker, Kerry Fisher, D J Kerr, Paul G Murray, Leonard W SeymourAbstract:Human endothelial-specific targeting peptides were identified by biopanning within freshly-obtained human Umbilical cords. Umbilical Veins were cleaned in situ and M13 phage display libraries were passed through the cords. Tightly bound phage were recovered following isolation of endothelial cells by collagenase digestion and homogenisation, allowing production of enriched phage libraries for subsequent rounds of panning. After five rounds of biopanning, five promising sequences were selected and the binding of the corresponding phage clones was compared in perfused Umbilical Veins. Each of these peptides showed substantial binding, although the clone encoding the heptapeptide KPSGLTY showed the greatest, some 89-times greater than insertless phage. Binding of this phage clone was examined to cells in vitro, where it demonstrated at least five-times greater binding to isolated human Umbilical vein endothelial cells than to 911, SKOV3, B16F10 and Cos7 cells. These initial peptides may prove useful targeting agents for endothelial-selective delivery, and this powerful approach should be readily applicable to biopanning in a broad range of human vessels ex vivo.
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use of a phage display library to identify oligopeptides binding to the lumenal surface of polarized endothelium by ex vivo perfusion of human Umbilical Veins
Journal of Drug Targeting, 2003Co-Authors: Fukuto Maruta, Alan L Parker, Kerry Fisher, D J Kerr, Paul G Murray, Leonard W SeymourAbstract:Human endothelial-specific targeting peptides were identified by biopanning within freshly-obtained human Umbilical cords. Umbilical Veins were cleaned in situ and M13 phage display libraries were passed through the cords. Tightly bound phage were recovered following isolation of endothelial cells by collagenase digestion and homogenisation, allowing production of enriched phage libraries for subsequent rounds of panning. After five rounds of biopanning, five promising sequences were selected and the binding of the corresponding phage clones was compared in perfused Umbilical Veins. Each of these peptides showed substantial binding, although the clone encoding the heptapeptide KPSGLTY showed the greatest, some 89-times greater than insertless phage. Binding of this phage clone was examined to cells in vitro, where it demonstrated at least five-times greater binding to isolated human Umbilical vein endothelial cells than to 911, SKOV3, B16F10 and Cos7 cells. These initial peptides may prove useful targeting agents for endothelial-selective delivery, and this powerful approach should be readily applicable to biopanning in a broad range of human vessels ex vivo.
Harry S Dweck - One of the best experts on this subject based on the ideXlab platform.
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release of superoxide dismutase activity from human Umbilical Veins by heparin
Journal of Perinatology, 1999Co-Authors: Zaheer A Gill, Ana Marie A Castillo, Louis Rosenfeld, Harry S DweckAbstract:OBJECTIVE: This study evaluated superoxide dismutase activity released from human Umbilical Veins incubated with different doses of heparin and examined at different time points. STUDY DESIGN: Umbilical Veins of fresh cords from full term babies were incubated with 175 or 1 U/ml of heparin at one end while the other end was incubated without heparin as control. Specimens were obtained at 10 minutes and 24 hours (high-dose) or at 10 minutes and 60 minutes (low-dose). Superoxide dismutase activity was measured by the cytochrome c method. Results were analyzed using Student’s paired t test. RESULTS: A time-dependent release of superoxide dismutase activity into the buffer was observed in both heparin specimens as well as in control specimens. The difference in release in the presence of heparin was of statistical significance, compared with the controls. CONCLUSION: Because heparin is routinely used as an anticoagulant to maintain the patency of Umbilical catheters, we conclude that this usage may alter a newborn’s response to oxygen free radical damage by changes in superoxide dismutase activity.
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release of superoxide dismutase from Umbilical Veins by low dose heparin used in intraarterial infusions 890
Pediatric Research, 1997Co-Authors: Zaheer A Gill, Ana Marie A Castillo, Harry S Dweck, Louis RosenfeldAbstract:Antioxidants such as superoxide dismutase (SOD) protect tissues from injury by inactivating oxygen free radicals. Extracellular SOD (EC-SOD) is bound to heparan sulfate, a structural component of the vascular extracellular matrix(ECM). In adults, high doses of heparin (H) competitively release EC-SOD from the vascular matrix into the blood, where it is rapidly degraded. In our previous study we showed that a high dose of H (175 units/ml) releases SOD from Umbilical Veins. The purpose of this study is to determine whether SOD is released by a lower dose of H (1 unit/ml), routinely used for catheter patency.
Markus Hoenicka - One of the best experts on this subject based on the ideXlab platform.
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development of endothelium denuded human Umbilical Veins as living scaffolds for tissue engineered small calibre vascular grafts
Journal of Tissue Engineering and Regenerative Medicine, 2013Co-Authors: Markus Hoenicka, Siegfried Schrammel, Georgine Huber, Christof Schmid, Jiri Bursa, Holger Bronger, Dietrich E BirnbaumAbstract:Tissue-engineered small-calibre vessel grafts may help to alleviate the lack of graft material for coronary and peripheral bypass grafting in an increasing number of patients. This study explored the use of endotheliumdenuded human Umbilical Veins (HUVs) as scaffolds for vascular tissue engineering in a perfusion bioreactor. Vessel diameter (1.2 � 0.4mm), wall thickness (0.38 � 0.09mm), uniaxial ultimate failure stress (8029 � 1714 kPa) and burst pressure (48.4 � 20.2 kPa, range 28.4–83.9 kPa) were determined in native samples. The effects of endothelium removal from HUVs by enzymatic digestion, hypotonic lysis and dehydration were assessed. Dehydration did not significantly affect contractile function, tetrazolium dye reduction, mechanical strength and vesselstructure,whereas the other methods failed in at leastone of these parameters. Denudation by dehydration retained laminin, fibronectin, collagen and elastic fibres. Denuded HUVs were seeded in a perfusion bioreactor with either allogeneic HUVs endothelial cells or with saphenous vein endothelial cells harvested from patients with coronary artery disease. Seeding in a perfusion bioreactor resulted in a confluent monolayer of endothelial cells from both sources, as judged by histology and scanning electron microscopy. Seeded cells contained von Willebrand factor and CD31. In conclusion, denuded HUVs should be considered an alternative to decellularized blood vessels, as the process keeps the smooth muscle layer intact and functional, retains proteins relevant for biomechanic properties and for cell attachment and provides a suitable scaffold for seeding an autologous and flow-resistant endothelium. Copyright © 2012 John Wiley & Sons, Ltd.
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tissue engineering of small caliber vessel grafts from human Umbilical Veins
2009Co-Authors: Markus Hoenicka, Siegfried Schrammel, Volker R Jacobs, Georgine Huber, Christof Schmid, Dietrich E BirnbaumAbstract:Human Umbilical Veins (HUV) have recently been suggested as a starting material for vascular tissue engineering. HUV possess a functional smooth muscle layer and could be turned into an immunologically inert graft with contractile properties by creating a neoendothelium from the recipient’s own cells. This study investigated methods to remove the native endothelium without impairing the contractile function of the smooth muscle layer. These denuded HUV were then seeded with endothelial cells in a perfusion bioreactor, demonstrating the creation of a confluent, shear-resistant neoendothelium.
Zaheer A Gill - One of the best experts on this subject based on the ideXlab platform.
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release of superoxide dismutase activity from human Umbilical Veins by heparin
Journal of Perinatology, 1999Co-Authors: Zaheer A Gill, Ana Marie A Castillo, Louis Rosenfeld, Harry S DweckAbstract:OBJECTIVE: This study evaluated superoxide dismutase activity released from human Umbilical Veins incubated with different doses of heparin and examined at different time points. STUDY DESIGN: Umbilical Veins of fresh cords from full term babies were incubated with 175 or 1 U/ml of heparin at one end while the other end was incubated without heparin as control. Specimens were obtained at 10 minutes and 24 hours (high-dose) or at 10 minutes and 60 minutes (low-dose). Superoxide dismutase activity was measured by the cytochrome c method. Results were analyzed using Student’s paired t test. RESULTS: A time-dependent release of superoxide dismutase activity into the buffer was observed in both heparin specimens as well as in control specimens. The difference in release in the presence of heparin was of statistical significance, compared with the controls. CONCLUSION: Because heparin is routinely used as an anticoagulant to maintain the patency of Umbilical catheters, we conclude that this usage may alter a newborn’s response to oxygen free radical damage by changes in superoxide dismutase activity.
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release of superoxide dismutase from Umbilical Veins by low dose heparin used in intraarterial infusions 890
Pediatric Research, 1997Co-Authors: Zaheer A Gill, Ana Marie A Castillo, Harry S Dweck, Louis RosenfeldAbstract:Antioxidants such as superoxide dismutase (SOD) protect tissues from injury by inactivating oxygen free radicals. Extracellular SOD (EC-SOD) is bound to heparan sulfate, a structural component of the vascular extracellular matrix(ECM). In adults, high doses of heparin (H) competitively release EC-SOD from the vascular matrix into the blood, where it is rapidly degraded. In our previous study we showed that a high dose of H (175 units/ml) releases SOD from Umbilical Veins. The purpose of this study is to determine whether SOD is released by a lower dose of H (1 unit/ml), routinely used for catheter patency.