title: Acellular scaffold implantation--no alternative to tissue engineering.
abstract: OBJECTIVE
  Degradation mechanisms of cardiovascular bioprostheses may play an important role in bioartificial implants. The fate of acellular implanted and cellular cardiovascular scaffolds was examined in an in vivo model.
  
  
  METHODS
  Decellularized or native ovine carotid artery (CA, n=42) and aorta (AO, n=42) were implanted subcutaneously into rats for 2, 4 and 8 weeks. Immunohistochemical methods were used to monitor repopulation. Desmin-vimentin, CD31-, CD4- and CD18-antibodies for myocytes, endothelium, and inflammatory cell-infiltration, respectively. Calcification was detected by von-Kossa staining. Cell density was quantified by DNA-isolation.
  
  
  RESULTS
  Acellular AO and CA matrices showed progressive calcification. Cellular AO and CA matrices trigger a strong inflammatory reaction which subsides after two weeks. CA scaffolds are revascularized progressively, whereas AO biocomposites degenerate. Calcification is less pronounced in cellular AO scaffolds and lacking in CA.
  
  
  CONCLUSIONS
  Acellular bioartificial implants demonstrate degradation mechanisms similar to currently applied cardiovascular bioprostheses. Cellularized viable implants are promising clinical alternatives.
authors.affiliation: Division of Thoracic and Cardiovascular Surgery, Hannover Medical School, Hannover, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Walles
authors.forename: C
authors.initials: C
authors.lastname: Puschmann
authors.forename: A
authors.initials: A
authors.lastname: Haverich
authors.forename: H
authors.initials: H
authors.lastname: Mertsching
mesh_terms: D000818:Animals; D001011:Aorta / Q000502:physiology; D001705:Bioprosthesis; D002339:Carotid Arteries / Q000502:physiology; D006350:Heart Valve Prosthesis; D023421:Models, Animal; D011474:Prosthesis Design / Q000379:methods*; D051381:Rats; D012756:Sheep; D023822:Tissue Engineering / Q000379:methods*