Decellularized aortic conduits: could their cryopreservation affect post-implantation outcomes? A morpho-functional study on porcine homografts.
Decellularized porcine aortic valve conduits (AVCs) implanted in a Vietnamese Pig (VP) experimental animal model were matched against decellularized and then cryopreserved AVCs to assess the effect of cryopreservation on graft hemodynamic performance and propensity to in vivo repopulation by host's cells. VPs (n = 12) underwent right ventricular outflow tract substitution using AVC allografts and were studied for 15-month follow-up. VPs were randomized into two groups, receiving AVCs treated with decellularization alone (D; n = 6) or decellularization/cryopreservation (DC; n = 6), respectively. Serial echocardiography was carried out to follow up hemodynamic function. All explanted AVCs were processed for light and electron microscopy. No signs of dilatation, progressive stenosis, regurgitation, and macroscopic calcification were echocardiographically observed in both D and DC groups. Explanted D grafts exhibited near-normal features, whereas the presence of calcification, inflammatory infiltrates, and disarray of elastic lamellae occurred in some DC grafts. In the unaltered regions of AVCs from both groups, almost complete re-endothelialization was observed for both valve cusps and aorta walls. In addition, side-by-side repopulation by recipient's fibroblasts, myofibroblasts, and smooth muscle cells was paralleled by ongoing tissue remodeling, as revealed by the ultrastructural identification of typical canals of collagen fibrillogenesis and elastogenesis-related features. Incipient neo-vascularization and re-innervation of medial and adventitial tunicae of grafted aortic walls were also detected for both D and DC groups. Cryopreservation did not affect post-implantation AVC hemodynamic behavior and was topically propensive to cell repopulation and tissue renewal, although graft deterioration including calcification was present in several areas. Thus, these preliminary data provide essential information on feasibility of decellularization and cryopreservation coupling in the perspective of treatment optimization and subsequent clinical trials using similarly treated human allografts as innovative heart valve substitutes.
Division of Cardiac Surgery, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Via Giustiniani 2, 35128, Padua, Italy. michelegallo@hotmail.co.uk.
Michele
M
Gallo
Department of Experimental and Clinical Medicine, University of Udine, Udine, Italy.
Antonella
A
Bonetti
Department of Animal Medicine, Productions and Health, University of Padua, Legnaro, Italy.
Helen
H
Poser
Division of Cardiac Surgery, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Via Giustiniani 2, 35128, Padua, Italy.
Filippo
F
Naso
Division of Cardiac Surgery, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Via Giustiniani 2, 35128, Padua, Italy.
Tomaso
T
Bottio
Division of Cardiac Surgery, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Via Giustiniani 2, 35128, Padua, Italy.
Roberto
R
Bianco
Tissue Bank of Veneto Region, Treviso Regional Hospital, Treviso, Italy.
Adolfo
A
Paolin
Department of Animal Medicine, Productions and Health, University of Padua, Legnaro, Italy.
Paolo
P
Franci
Department of Animal Medicine, Productions and Health, University of Padua, Legnaro, Italy.
Roberto
R
Busetto
Department of Cardiac, Thoracic and Vascular Sciences, Biostatistics, Epidemiology and Public Health Unit, University of Padua, Padua, Italy.
Anna Chiara
AC
Frigo
Department of Cardiothoracic Surgery, Royal Children's Hospital, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Australia.
Edward
E
Buratto
Department of Biomedical Sciences, University of Padua, Padua, Italy.
Michele
M
Spina
Department of Experimental and Clinical Medicine, University of Udine, Udine, Italy.
Maurizio
M
Marchini
Department of Experimental and Clinical Medicine, University of Udine, Udine, Italy.
Fulvia
F
Ortolani
Division of Cardiac Surgery, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Via Giustiniani 2, 35128, Padua, Italy.|Cardiovascular Regenerative Medicine, Venetian Institute of Molecular Medicine (VIMM), Biomedical Campus Pietro d'Abano, Padua, Italy.
Laura
L
Iop
Division of Cardiac Surgery, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Via Giustiniani 2, 35128, Padua, Italy.|Cardiovascular Regenerative Medicine, Venetian Institute of Molecular Medicine (VIMM), Biomedical Campus Pietro d'Abano, Padua, Italy.
Gino
G
Gerosa
D064591:Allografts; D000818:Animals; D001011:Aorta / Q000503:physiopathology / Q000637:transplantation* / Q000648:ultrastructure; D001021:Aortic Valve / Q000503:physiopathology / Q000637:transplantation* / Q000648:ultrastructure; D001705:Bioprosthesis; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D049109:Cell Proliferation; D015925:Cryopreservation; D004452:Echocardiography; D006085:Graft Survival; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D006439:Hemodynamics; D046529:Microscopy, Electron, Transmission; D023421:Models, Animal; D011183:Postoperative Complications / Q000473:pathology / Q000503:physiopathology; D013552:Swine; D013997:Time Factors
Bioengineering; Cryopreservation; Decellularization; Echocardiography; Heart valve; Preclinical model