title: Decellularization does not eliminate thrombogenicity and inflammatory stimulation in tissue-engineered porcine heart valves.
abstract: OBJECTIVE
  In tissue engineering of heart valves using decellularized xenogenic valves, it has been suggested that cell elimination would result in a biologically inert matrix. The aim of this in-vitro investigation was to evaluate different decellularization methods in regard to the completeness of cell removal, inflammatory response, and thrombocyte activation.
  
  
  METHODS
  Decellularized porcine Synergraft valves were compared with porcine pulmonary conduits decellularized with Triton X-100, sodium deoxycholate, Igepal CA-630 and ribonuclease. Completeness of decellularization was evaluated with staining for nuclei and alpha-Gal epitope. Decellularized heart valves with and without seeding with endothelial cells (ECs) were incubated with human platelet-rich plasma and stained for CD41 and PAC-1 to evaluate thrombocyte activation. Samples were processed for laser scanning microscopy (LSM) and scanning electron microscopy (SEM). Migration of human monocytic cells towards extracted valve proteins was tested.
  
  
  RESULTS
  In contrast to the Synergraft, complete cell removal and elimination of the alpha-gal epitope was achieved with the new decellularization method. Numerous adherent and activated platelets were found on the decellularized matrix. This was inhibited by seeding with ECs. Even in completely cell-free valve tissue extracellular matrix proteins attracted human monocytic cells as in early inflammation, depending on whether porcine or human tissue was used.
  
  
  CONCLUSIONS
  Important differences were found in the decellularization efficacy of treatment methods. However, even complete elimination of cells and their remnants did not result in a biologically inert matrix. The decellularized porcine heart valve matrix has the potential to attract inflammatory cells and to induce platelet activation. These findings suggest that it will be important to control the different inflammation-stimulating factors if porcine tissues are to be used successfully in tissue engineering.
authors.affiliation: Department of Cardiothoracic Surgery, Medical University of Vienna, Vienna, Austria.
authors.forename: Marie-Theres
authors.initials: MT
authors.lastname: Kasimir
authors.forename: Erwin
authors.initials: E
authors.lastname: Rieder
authors.forename: Gernot
authors.initials: G
authors.lastname: Seebacher
authors.forename: Anneliese
authors.initials: A
authors.lastname: Nigisch
authors.forename: Barbara
authors.initials: B
authors.lastname: Dekan
authors.forename: Ernst
authors.initials: E
authors.lastname: Wolner
authors.forename: Guenter
authors.initials: G
authors.lastname: Weigel
authors.forename: Paul
authors.initials: P
authors.lastname: Simon
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000187:drug effects; D003840:Deoxycholic Acid / Q000494:pharmacology; D003902:Detergents / Q000494:pharmacology; D004195:Disease Models, Animal; D006349:Heart Valve Diseases / Q000473:pathology / Q000601:surgery; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects*; D018613:Microscopy, Confocal; D017830:Octoxynol / Q000494:pharmacology; D015539:Platelet Activation / Q000187:drug effects; D011092:Polyethylene Glycols / Q000494:pharmacology; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control; D011474:Prosthesis Design; D011664:Pulmonary Valve / Q000187:drug effects / Q000601:surgery / Q000648:ultrastructure; D012260:Ribonucleases / Q000494:pharmacology; D013552:Swine; D013927:Thrombosis / Q000209:etiology / Q000517:prevention & control*; D016610:Tissue Embedding / Q000379:methods*
chemical_list: D003902:Detergents; D003840:Deoxycholic Acid; D011092:Polyethylene Glycols; D017830:Octoxynol; C010615:Nonidet P-40; D012260:Ribonucleases