RECONSTRUCTIVE UROLOGY

Engineering of a vascularized scaffold for artificial tissue and organ generation
Mertsching H, Walles T, Hofmann M, Schanz J, Knapp WH
Fraunhofer Institute for Interfacial Engineering and Biotechnology, Stuttgart, Germany, Tissue Engineering Network, Hannover Medical School, 30659 Hannover, Germany
Biomaterials 2005 Jun 22; [Epub ahead of print]

• Tissue engineering is an emerging field in regenerative medicine to overcome the problem of end-stage organ failure. However, complex tissues and organs need a vascular supply to guaranty graft survival and render bioartificial organ function. Here we developed methods to decellularize porcine small bowl segments and repopulate the remaining venous and arterial tubular structures within these matrices with allogeneic porcine endothelial progenitor cells. Cellular adherence and vitality was characterized by quantitative 2-[(18)F]-fluoro-2'-desoxy-glucose (FDG) positron emission tomography (PET) and subsequent immunohistological work up. The generated matrices showed insulin-dependent FDG uptake predominantly in the region of the former vascular structures. Stain for vitality and the specific endothelial markers CD31, VE-Cadherin and Flk-1 matched this functional finding. Providing evidence for vitality up to 3 weeks post reconstitution and typical endothelial differentiation, these results indicate that our generated matrix allows the generation of complex bioartificial tissues and organs for experimental and future clinical application.
  
  
• Editorial Comment
  So far, one of the limiting factors in using cultivated tissue flaps or in vitro generation of whole organs was vascularization. Bioartificial grafts will usually become necrotic in the centre before sufficient revascularization takes place whenever a graft is implanted into the donor organism. The authors referring their results from Stuttgart, Germany and belong to one of the most advanced institutions dealing with biomaterials for regenerative medicine. They have shown that by using allogeneic porcine endothelial progenitor cells vascularization of acellular tissue flaps became possible. The achievements of this study were twofold: The authors were able to show that an endothelial differentiation was possible from their progenitor cells, and that with the help of progenitor cells differentiating into endothelial cells revascularization became possible as well. Once we achieve the goal of a “fast-track” revascularization of artificially cultivated flaps, we will be able to use much larger tissues and only then, we will be able to think about urinary bladder off the shelf.

Dr. Arnulf Stenzl
Professor and Chairman of Urology
Eberhard-Karls-University Tuebingen
Tuebingen, Germany