Author
G. Weigel
Bio: G. Weigel is an academic researcher from University of Vienna. The author has contributed to research in topics: Endothelium & Mycophenolic acid. The author has an hindex of 6, co-authored 14 publications receiving 905 citations.
Papers
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TL;DR: The xenogenic collagen matrix of the Synergraft valve elicits a strong inflammatory response in humans which is non-specific early on and is followed by a lymphocyte response, which may indicate manufacturing problems.
Abstract: Objectives: The first tissue engineered decellularized porcine heart valve, Synergrafte (Cryolife Inc., USA) was introduced in Europe as an alternative to conventional biological valves. This is the first report of the rapid failure of these new grafts in a small series. Materials and methods: In 2001, 2 model 500 and 2 model 700 Synergrafte valves were implanted in four male children (age 2.5‐ 11 years) in the right ventricular outflow tract as a root. Two patients had a Ross operation and two had a homograft replacement. Results: The cryopreserved Synergrafte valves appeared macroscopically unremarkable at implantation. Recovery from surgery was uneventful and good valve function was demonstrated postoperatively. Three children died, two suddenly with severely degenerated Synergrafte valves 6 weeks and 1 year after implantation. The third child died on the 7th day due to Synergrafte rupture. Subsequently the fourth graft was explanted prophylactically 2 days after implantation. Macroscopically all four grafts showed severe inflammation starting on the outside (day 2 explant) leading to structural failure (day 7 explant) and severe degeneration of the leaflets and wall (6 weeks and 1 year explant). Histology demonstrated severe foreign body type reaction dominated by neutrophil granulocytes and macrophages in the early explants and a lymphocytic reaction at 1 year. In addition significant calcific deposits were demonstrated at all stages. Surprisingly pre-implant samples of the Synergrafte revealed incomplete decellularization and calcific deposits. No cell repopulation of the porcine matrix occurred. Conclusion: The xenogenic collagen matrix of the Synergrafte valve elicits a strong inflammatory response in humans which is non-specific early on and is followed by a lymphocyte response. Structural failure or rapid degeneration of the graft occurred within 1 year. Calcific deposits before implantation and incomplete decellularization may indicate manufacturing problems. The porcine Synergrafte treated heart valves should not be implanted at this stage and has been stopped. q 2003 Elsevier Science B.V. All rights reserved.
623 citations
TL;DR: Techniques of decellularization are highly variable in efficiency and matrix preservation and was best achieved in this study with Triton-X100® and sodium deoxycholate.
Abstract: BackgroundTissue engineering of heart valves should avoid the disadvantages of conventional prostheses. In this study we tested different decellularization procedures for their potential of cell re...
210 citations
TL;DR: In this patient group, statistical analysis failed to show a direct correlation between duration of circulatory interruption and neurologic outcome, and the incidence of permanent neurologic dysfunction as well as the mortality rate are predominantly related to the age of the patient.
41 citations
TL;DR: Using antioxidants, the modulating function of reactive oxygen species on the eicosanoid metabolism in endothelial cells was verified and could contribute to the reduction of the protective function of the endothelium in hemostasis and vascular tone.
31 citations
TL;DR: It appears that one mechanism of the clinically observed effectiveness of aprotinin lies in the altered ratio of 6-keto-prostaglandin F1 alpha: thromboxane B2 in endothelial cells, which leads to enhanced platelet aggregation and improved vessel sealing.
21 citations
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TL;DR: Tissue decellularization with preservation of ECM integrity and bioactivity can be optimized by making educated decisions regarding the agents and techniques utilized during processing.
2,677 citations
TL;DR: It is shown that, in the vast majority of circumstances, the sole requirement for biocompatibility in a medical device intended for long-term contact with the tissues of the human body is that the material shall do no harm to those tissues, achieved through chemical and biological inertness.
2,219 citations
TL;DR: The ability of pore size and porosity of scaffolds to direct cellular responses and alter the mechanical properties of scaffold will be reviewed, followed by a look at nature's own scaffold, the extracellular matrix.
Abstract: Tissue engineering applications commonly encompass the use of three-dimensional (3D) scaffolds to provide a suitable microenvironment for the incorporation of cells or growth factors to regenerate ...
2,075 citations
TL;DR: The most commonly used decellularization methods are described, and consideration give to the effects of these methods upon the biologic scaffold material.
2,007 citations
TL;DR: An overview of the composition and structure of selected ECM scaffolding materials, the effects of manufacturing methods upon the structural properties and resulting mechanical behavior of the scaffold materials, and the in vivo degradation and remodeling of ECm scaffolds with an emphasis on tissue function is provided.
1,345 citations