title: Immunological and histological evaluation of decellularized allograft in a pig model: comparison with cryopreserved allograft.
abstract: OBJECTIVE
  The remodeling process of the decellularized allograft after implantation remains unclear. Herein, the hemodynamics, recellularization and immunological response of the decellularized allograft were evaluated at four weeks after implantation in a mini-pig model, and compared with a cryopreserved allograft.
  
  
  METHODS
  Six porcine pulmonary allografts were harvested from mini-pigs, and cryopreserved for four weeks. In two pigs, the grafts were decellularized with Triton X solution, after which static reseeding of the valve surface was performed for 48 h with autologous endothelial cells harvested from a leg artery. Decellularization, but not reseeding, was carried out in two mini-pigs, and cryopreservation alone in two mini-pigs. Whilst under right heart bypass, the right ventricular outflow tract was replaced in six minipigs. The grafts were explanted after four weeks; analysis included direct pressure measurement, echocardiography, macroscopy, light microscopy with hematoxylin and eosin staining, and immunohistochemical studies to identify macrophages, T lymphocytes, and endothelial cells.
  
  
  RESULTS
  Hemodynamically and macroscopically, there were no major differences between the three groups. In the cryopreservation-only group, immunohistochemistry showed an influx of macrophages, and T lymphocytes at the cusps. Endothelial cell coverage was found in the decellularized and decellularized + cell-seeded groups, but no macrophages and T lymphocytes were found at the cusps.
  
  
  CONCLUSIONS
  Decellularization of the cryopreserved allograft may reduce the inflammatory response and improve its long-term durability.
authors.affiliation: Department of Cardiovascular Surgery, National Cardiovascular Center, Osaka, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Numata
authors.forename: Toshiya
authors.initials: T
authors.lastname: Fujisato
authors.forename: Kazuo
authors.initials: K
authors.lastname: Niwaya
authors.forename: Hatsue
authors.initials: H
authors.lastname: Ishibashi-Ueda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakatani
authors.forename: Soichiro
authors.initials: S
authors.lastname: Kitamura
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D015925:Cryopreservation; D004452:Echocardiography; D042783:Endothelial Cells / Q000378:metabolism; D007150:Immunohistochemistry; D007249:Inflammation; D023421:Models, Animal; D011664:Pulmonary Valve / Q000166:cytology / Q000276:immunology / Q000473:pathology / Q000637:transplantation*; D011665:Pulmonary Valve Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology; D011669:Pulmonary Wedge Pressure; D013552:Swine; D013556:Swine, Miniature; D016378:Tissue Transplantation; D014184:Transplantation, Homologous