title: Recellularization of decellularized allograft scaffolds in ovine great vessel reconstructions.
abstract: BACKGROUND
  Decellularized allograft tissues have been identified as a potential extracellular matrix (ECM) scaffold on which to base recellularized tissue-engineered vascular and valvular substitutes. Decreased antigenicity and the capacity to recellularize suggest that such constructs may have favorable durability. Detergent/enzyme decellularization methods remove cells and cellular debris while leaving intact structural protein "scaffolds." Allograft pulmonary artery tissues decellularized with an anionic detergent/enzyme methodology were tested in a long-term implantation model that used arterial wall repairs in the great vessels of juvenile sheep.
  
  
  METHODS
  Twelve test sheep were implanted (n = 4) for each of three different scaffold protocols that compared traditional dimethylsulfoxide cryopreservation, cryopreservation followed by decellularization, and decellularization of fresh tissue. Four additional sheep served as controls (n = 2 sham, n = 2 fresh tissue). Patches were fashioned and implanted into pulmonary artery and aortic defects. Panel reactive antibodies (PRA) were measured over time (10 to 20 weeks). Explant histopathology determined recellularization morphology as well as calcium, collagen, and elastin distribution within explanted tissue.
  
  
  RESULTS
  Unlike traditionally cryopreserved tissues, the decellularized tissues contained no residual cells or cellular debris before implantation, which correlated with measurable reductions in PRA. Decellularized explants demonstrated time-dependent migration of recipient cells through matrix, typically staining positive for alpha-smooth muscle actin with no calcification.
  
  
  CONCLUSIONS
  The properties demonstrated seem consistent with characteristics necessary for implantable tissue-engineered scaffolds. The decellularization method described appears to create a biologically suitable ECM scaffold for in vivo migration of phenotypically appropriate cells while avoiding antigenicity and calcification.
authors.affiliation: Department of Cardiothoracic Surgery and the Collis Cardiac Surgical Laboratory, Brown University and Rhode Island Hospital, Providence, Rhode Island, USA.
authors.forename: Ara
authors.initials: A
authors.lastname: Ketchedjian
authors.forename: Alyce Linthurst
authors.initials: AL
authors.lastname: Jones
authors.forename: Paula
authors.initials: P
authors.lastname: Krueger
authors.forename: Elliot
authors.initials: E
authors.lastname: Robinson
authors.forename: Katrina
authors.initials: K
authors.lastname: Crouch
authors.forename: Lloyd
authors.initials: L
authors.lastname: Wolfinbarger
authors.forename: Richard
authors.initials: R
authors.lastname: Hopkins
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology* / Q000637:transplantation*; D011126:Polypropylenes; D011651:Pulmonary Artery / Q000166:cytology* / Q000637:transplantation*; D012756:Sheep; D013997:Time Factors; D014656:Vascular Surgical Procedures / Q000379:methods
chemical_list: D011126:Polypropylenes