title: In vivo cellularization of a cross-linked matrix by intraperitoneal implantation: a new tool in heart valve tissue engineering.
abstract: OBJECTIVE
  To use in vivo instead of in vitro cell seeding in heart valve tissue engineering.
  
  
  RESULTS
  Intraperitoneally preseeded, photo-oxidized bovine pericardial pulmonary valve constructs (group 1) were compared with non-preseeded constructs (group 2) implanted in sheep. All valves functioned normally and were macroscopically intact at explantation [1 week (n = 6) and 1 month (n = 6) in each group], except for one thrombosed leaflet in a group-2 valve at 1 month. Almost 10-fold higher neomatrix deposition and doubling of the leaflet thickness were found in group 1 vs. 2 (P < 0.05). A concomitant significant decrease in leaflet length (15%) was found at 1 month in group 1. The total cross-sectional surface and total amount of collagen of the original matrix remained unchanged in both groups at all times. Immunohistochemistry showed a low immune response, stem/progenitor cell infiltration, appropriated differentiation, and spontaneous endothelialization of the valves. Significantly, increased re-cellularization was found after IP preseeding compared with spontaneous seeding: cell coverage of the leaflet was 71-100 vs. 8-26% (P < 0.05), respectively.
  
  
  CONCLUSIONS
  Complete re-cellularization can be obtained by IP preseeding of an acellularized cross-linked matrix. Well-functioning valve constructs show cellularization and differentiation into myofibroblast phenotype and concomitant neomatrix deposition.
authors.affiliation: Laboratory for Experimental Cardiac Surgery, Department of Cardiovascular Diseases, Katholieke Universiteit Leuven, Minderbroedersstraat 17, 3000 Leuven, Belgium. geofrey.devisscher@med.kuleuven.be
authors.forename: Geofrey
authors.initials: G
authors.lastname: De Visscher
authors.forename: Ilse
authors.initials: I
authors.lastname: Vranken
authors.forename: An
authors.initials: A
authors.lastname: Lebacq
authors.forename: Christiaan
authors.initials: C
authors.lastname: Van Kerrebroeck
authors.forename: Javier
authors.initials: J
authors.lastname: Ganame
authors.forename: Erik
authors.initials: E
authors.lastname: Verbeken
authors.forename: Willem
authors.initials: W
authors.lastname: Flameng
mesh_terms: D000818:Animals; D001705:Bioprosthesis; D002452:Cell Count; D003432:Cross-Linking Reagents; D046508:Culture Techniques; D005260:Female; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000379:methods; D007150:Immunohistochemistry; D012756:Sheep; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D003432:Cross-Linking Reagents