title: Complete dynamic repopulation of decellularized heart valves by application of defined physical signals-an in vitro study.
abstract: OBJECTIVE
  Cardiovascular tissue engineering is a novel concept to develop ideal heart valve substitutes. The objective of this study was to use decellularized porcine pulmonary valves, ovine cells and dynamic tissue culture to obtain viable and biomechanically stable constructs, resembling native aortic heart valves.
  
  
  METHODS
  Endothelial cells and myofibroblasts were obtained from ovine carotid arteries. Porcine pulmonary valves were decellularized enzymatically, reseeded and cultured using a hydrodynamic bioreactor system over a time period of 9 or 16 days. Controls were grown over an equivalent time period under static conditions. Specimens of each valve were examined biochemically (cell proliferation, DNA, collagen, 4-hydroxyproline, elastin and glycosaminoglycans), histologically (hematoxylin-eosin, Movat-pentachrome and immunostains) and mechanically (radial and circumferential strength).
  
  
  RESULTS
  Histology and biochemical assays demonstrated the removal of almost all cells after decellularization with preservation of the extracellular matrix. Recellularization under pulsatile conditions was significantly improved after 9 and 16 days compared to static conditions. Biochemical and mechanical analysis revealed a continuous increase of cell mass, collagen and elastin contents and strength under pulsatile culture conditions compared to significantly lower values in the static controls.
  
  
  CONCLUSIONS
  This study demonstrated the superiority of the hydrodynamic approach of cellular reseeding to replace decellularized porcine heart valves with ovine cells with almost complete preservation of extracellular matrix integrity.
authors.affiliation: Department of Cardiothoracic and Vascular Surgery, Friedrich-Schiller-University, Bachstrasse 18, 07743 Jena, Germany. katja.schenke@med.uni-jena.de
authors.forename: K
authors.initials: K
authors.lastname: Schenke-Layland
authors.forename: F
authors.initials: F
authors.lastname: Opitz
authors.forename: M
authors.initials: M
authors.lastname: Gross
authors.forename: C
authors.initials: C
authors.lastname: Döring
authors.forename: K J
authors.initials: KJ
authors.lastname: Halbhuber
authors.forename: F
authors.initials: F
authors.lastname: Schirrmeister
authors.forename: Th
authors.initials: T
authors.lastname: Wahlers
authors.forename: U A
authors.initials: UA
authors.lastname: Stock
mesh_terms: D000818:Animals; D001021:Aortic Valve; D019149:Bioreactors; D002339:Carotid Arteries; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000502:physiology; D005109:Extracellular Matrix / Q000502:physiology; D008855:Microscopy, Electron, Scanning; D032383:Myocytes, Cardiac / Q000502:physiology; D012756:Sheep; D018709:Statistics, Nonparametric; D013552:Swine; D023822:Tissue Engineering / Q000379:methods*