title: Preclinical testing of tissue-engineered heart valves re-endothelialized under simulated physiological conditions.
abstract: BACKGROUND
  The in vivo regeneration capacity of decellularized heart valve grafts is still controversial. The aim of this study was to evaluate function, morphological changes, and cellular composition of decellularized versus re-endothelialized ovine pulmonary valves (PV) after implantation into lambs for 1 or 3 months.
  
  
  RESULTS
  PV (n=21) were decellularized using detergents. Twelve PV were repopulated with autologous jugular veins endothelial cells (ECs) in a dynamic pulsatile bioreactor under simulated physiological conditions. Morphological evaluation before implantation included histological stainings (H&E, Movat-pentachrome, von-Kossa, DAPI), immunostainings (anti-perlecan, anti-eNOS, anti-procollagen-I, anti-SM-alpha-actin), electron microscopy (EM), and DNA extraction. Decellularization led to cell-free scaffolds with preserved extracellular matrix (ECM) including basement membrane. Reseeded PV (n=5) were completely covered with ECs expressing endothelial nitric oxide synthase (eNOS) and von Willebrand factor (vWF). The function of orthotopically implanted decellularized and re-endothelialized PV (n=7, each) was analyzed after 1 and 3 months by echocardiography and revealed no differences in competence between both groups. A confluent EC monolayer expressing eNOS/vWF was only found in re-endothelialized PV but not in decellularized PV, whereas the valve matrices were comparable repopulated with interstitial cells expressing SM-alpha-actin and procollagen-I. More thrombotic and neointima formations were observed in decellularized PV. No signs of calcification were detected in both PV types.
  
  
  CONCLUSIONS
  In vitro re-endothelialization of detergent-decellularized valves with autologous ECs under simulated physiological conditions significantly improves total EC valve coverage 3 months after implantation, whereas the valve repopulation with interstitial cells in vivo occurs most likely by cell migration inside the scaffold.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Medical School Hannover, Hannover, Germany. lichtenberg.artur@mh-hannover.de
authors.forename: Artur
authors.initials: A
authors.lastname: Lichtenberg
authors.forename: Igor
authors.initials: I
authors.lastname: Tudorache
authors.forename: Serghei
authors.initials: S
authors.lastname: Cebotari
authors.forename: Mark
authors.initials: M
authors.lastname: Suprunov
authors.forename: Greta
authors.initials: G
authors.lastname: Tudorache
authors.forename: Heidi
authors.initials: H
authors.lastname: Goerler
authors.forename: Joon-Keun
authors.initials: JK
authors.lastname: Park
authors.forename: Denise
authors.initials: D
authors.lastname: Hilfiker-Kleiner
authors.forename: Stefanie
authors.initials: S
authors.lastname: Ringes-Lichtenberg
authors.forename: Matthias
authors.initials: M
authors.lastname: Karck
authors.forename: Gudrun
authors.initials: G
authors.lastname: Brandes
authors.forename: Andres
authors.initials: A
authors.lastname: Hilfiker
authors.forename: Axel
authors.initials: A
authors.lastname: Haverich
mesh_terms: D000818:Animals; D001705:Bioprosthesis; D019149:Bioreactors; D002114:Calcinosis / Q000209:etiology; D003902:Detergents / Q000494:pharmacology; D042783:Endothelial Cells / Q000166:cytology*; D004730:Endothelium, Vascular / Q000166:cytology; D005109:Extracellular Matrix / Q000637:transplantation*; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D006965:Hyperplasia; D020007:Implants, Experimental; D007601:Jugular Veins / Q000166:cytology; D008855:Microscopy, Electron, Scanning; D011183:Postoperative Complications / Q000209:etiology; D011312:Pressure; D011664:Pulmonary Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D012756:Sheep; D013927:Thrombosis / Q000209:etiology; D023822:Tissue Engineering / Q000295:instrumentation / Q000379:methods*; D014182:Transplantation, Autologous; D017539:Tunica Intima / Q000473:pathology; D014463:Ultrasonography
chemical_list: D003902:Detergents