title: Percutaneous pulmonary valve replacement: autologous tissue-engineered valved stents.
abstract: OBJECTIVE
  Percutaneous implantation has already been used clinically and is a great option for treating young patients. The use of autologous tissue-engineered valved stents might solve the problem of degeneration and limited durability of biological heart valves.
  
  
  RESULTS
  Porcine pulmonary heart valves and small intestinal submucosa were obtained from a slaughterhouse. The intestinal submucosa was used to cover the inside of the porcine pulmonary valved stents. Endothelial cells (ECs) and autologous myofibroblasts (MFs) were used from carotid artery segments of juvenile sheep. After MF seeding, constructs were placed in a dynamic bioreactor system and cultured for 16 days. After additional EC seeding, tissue-engineered valved stents were percutaneously deployed into the annulus of the pulmonary valve (n = 9). Angiography was performed at implantation and 4-week follow-up. Constructs were analysed radiographically, by post-mortem examination, and microscopically. In all but one case, orthotopic positioning of the stents (n = 6) at the time of implantation and explantation was observed angiographically, macroscopically, and by computer tomography scan and demonstrated normal valve function (n = 7). Gross morphology confirmed excellent opening and closure characteristics of all leaflets after 4 weeks (n = 7). Strong expression of α-smooth muscle actin in neo-interstitial cells and of von Willebrand factor and PECAM-1 in ECs was revealed by immunocytochemistry.
  
  
  CONCLUSIONS
  Good functioning and morphological characteristics were observed after percutaneous tissue-engineered valved stent implantation with autologous cells. This implantation of autologous tissue-engineered valved stents will become a valid future option in adolescents.
authors.affiliation: Department of Cardiovascular Surgery, School of Medicine, Christian-Albrechts-University of Kiel, Arnold-Heller-Str. 7, D-24105 Kiel, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Metzner
authors.forename: Ulrich A
authors.initials: UA
authors.lastname: Stock
authors.forename: Kenji
authors.initials: K
authors.lastname: Iino
authors.forename: Gunther
authors.initials: G
authors.lastname: Fischer
authors.forename: Tim
authors.initials: T
authors.lastname: Huemme
authors.forename: Jessica
authors.initials: J
authors.lastname: Boldt
authors.forename: Jan Hinrich
authors.initials: JH
authors.lastname: Braesen
authors.forename: Berthold
authors.initials: B
authors.lastname: Bein
authors.forename: Jochen
authors.initials: J
authors.lastname: Renner
authors.forename: Jochen
authors.initials: J
authors.lastname: Cremer
authors.forename: Georg
authors.initials: G
authors.lastname: Lutter
mesh_terms: D000497:Alloys; D000792:Angiography; D000818:Animals; D002478:Cells, Cultured; D004452:Echocardiography; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation / Q000379:methods*; D007413:Intestinal Mucosa / Q000166:cytology; D023421:Models, Animal; D058628:Myofibroblasts / Q000166:cytology; D011664:Pulmonary Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D012756:Sheep; D015607:Stents; D013552:Swine; D023822:Tissue Engineering; D014183:Transplantation, Heterologous
chemical_list: D000497:Alloys; C013616:nitinol