title: Evaluation of the biological behavior of decellularized pulmonary homografts: an experimental sheep model.
abstract: BACKGROUND
  The cryopreserved homograft is a good valve substitute due attributes like excellent hemodynamics, low incidence of thromboembolic events, infection resistance and good mid-term durability. However, progressive homograft degeneration and fibrocalcification may occur, particularly in the childhood and young adults. Their antigenicity triggers an immunological reaction that plays an important role in their degeneration and failure. The decellularization process was proposed to decrease this antigenicity. By the action of detergents and enzymes, this process removes all cellular components from the homograft matrix, diminishing immunogenicity and probably delaying its degeneration.
  
  
  OBJECTIVE
  The objective of this experimental and descriptive study is to evaluate the biological and functional behavior of decellularized pulmonary homografts (Decell-H), treated by a sodium dodecil sulfate solution (0.1%), developed in our University (Pontifícia Universidade Católica do Paraná). For the characterization of Decell-H performance, parameters like recellularization, calcification, and echocardiographic data will be analyzed.
  
  
  METHODS
  Eight juvenile sheep were submitted to the implantation of the Decell-H sutured into orthotopic position, through a left thoracotomy and with cardiopulmonary bypass support. They were followed-up clinically and by periodical echocardiograms until the explantation, which were performed in different time for every two sheep: seven, 30, 90 and 180 postoperative days. For histological analysis we used Hematoxilin-eosin, Movat and Alizarin-Red staining.
  
  
  RESULTS
  The sheep reached their follow-up period in a good clinical state. There was no valve regurgitation or stenonis by the echocardiogram. The animals submitted to the explantation in 90 and 180 days had a significant somatic growth and these Decell-H(s) had a diameter increase, without central valve insufficiency. Histologically, all homografts preserved their extra-cellular matrix organization and were progressively recellularized, without calcification.
  
  
  CONCLUSIONS
  In this experimental model, the Decell-H behaved as an excellent valve substitute.
authors.affiliation: SBCCV, Hospital Pequeno Príncipe of Curitiba, PR, Brazil. fabiobnavarro@gmail.com
authors.forename: Fábio Binhara
authors.initials: FB
authors.lastname: Navarro
authors.forename: Francisco Diniz Affonso da
authors.initials: FD
authors.lastname: Costa
authors.forename: Leonardo Andrade
authors.initials: LA
authors.lastname: Mulinari
authors.forename: Gustavo Klug
authors.initials: GK
authors.lastname: Pimentel
authors.forename: João Gabriel
authors.initials: JG
authors.lastname: Roderjan
authors.forename: Eduardo Discher
authors.initials: ED
authors.lastname: Vieira
authors.forename: Lúcia de
authors.initials: Ld
authors.lastname: Noronha
authors.forename: Nelson Itiro
authors.initials: NI
authors.lastname: Miyague
mesh_terms: D000818:Animals; D004452:Echocardiography; D005260:Female; D008297:Male; D023421:Models, Animal; D011664:Pulmonary Valve / Q000187:drug effects / Q000473:pathology / Q000637:transplantation*; D012756:Sheep; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology*; D013501:Surface-Active Agents / Q000494:pharmacology*; D023822:Tissue Engineering / Q000379:methods*; D014184:Transplantation, Homologous
chemical_list: D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate