Orthotopic replacement of the aortic valve with decellularized allograft in a sheep model.
Tissue engineered (TE) allografts have been successfully applied in pulmonary circulation. The behavior of TE valves based on decellularized scaffolds in systemic circulation remains unexplored. We investigated the function, histological changes, potential of in-vivo re-endothelialization of decellularized aortic valve allografts in orthotopic position in sheep. Ovine aortic valve conduits (n=12) were decellularized with detergents and implanted as an aortic root in lambs (35-45kg). For controls, fresh native ovine aortic valve conduits (n=6) were implanted. The valves were explanted at 3 and 9 months. In the experimental group, the valves exhibited trivial regurgitation and normal morphology with no signs of graft dilatation, degeneration or rejection. In some animals (n=2), we documented minimal calcification in the area of arterial anastomosis and in one, microthrombi formation on the leaflet surface. The luminal sides of the grafts were partially covered with an endothelial cell monolayer, neovasculogenesis was observed at the adventitial side. The valves in the control group appeared thickened, shrunken with marked calcification/degeneration signs, and advanced valve insufficiency. Detergent decellularized aortic valve allografts satisfy the higher requirements of the systemic circulation in sheep. As valve conduits become repopulated by endothelial and interstitial cells, they may re-gain the potential for growth.
Baraki
Hassina
H
Department of Cardio-Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
Tudorache
Igor
I
Braun
Maike
M
Höffler
Klaus
K
Görler
Adelheid
A
Lichtenberg
Artur
A
Bara
Christopher
C
Calistru
Alex
A
Brandes
Gudrun
G
Hewicker-Trautwein
Marion
M
Hilfiker
Andres
A
Haverich
Axel
A
Cebotari
Serghei
S
D000818:Animals; D001021:Aortic Valve / Q000166:cytology* / Q000648:ultrastructure; D004452:Echocardiography; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D007150:Immunohistochemistry; D018625:Microscopy, Atomic Force; D012756:Sheep; D023822:Tissue Engineering / Q000379:methods; D014184:Transplantation, Homologous