In-vitro assessment of the functional performance of the decellularized intact porcine aortic root.
OBJECTIVE
Tissue-engineered heart valves offer the potential to deliver a heart valve replacement that will develop with the young patient. The present authors' approach is to use decellularized aortic heart valves reseeded in vitro or in vivo with the patient's own cells. It has been reported that treatment of porcine aortic valve leaflets with 0.1% (w/v) sodium dodecyl sulfate (SDS) in hypotonic buffer produced complete leaflet acellularity without affecting tissue strength. The present study aim was to investigate the effect of an additional treatment incorporating 1.25% (w/v) trypsin and 0.1% (w/v) SDS on the biomechanics and hydrodynamics of the aortic root. This treatment has been shown to produce decellularization of both the aorta and valve leaflets.


METHODS
Fresh porcine aortic roots were treated to reduce the thickness of their aortic wall, and incubated in hypotonic buffer for 24 h. The leaflets were masked with agarose gel, and the aorta was treated with 1.25% (w/v) trypsin for 4 h at 37 degrees C. The trypsin and agarose were removed and the roots incubated with 0.1% (w/v) SDS in hypotonic buffer for 24 h. Fresh and treated circumferential and axial aortic specimens were subjected to uniaxial tensile testing, while intact porcine aortic roots were subjected to dilation and pulsatile flow testing.


RESULTS
Decellularized aortic wall specimens demonstrated significantly decreased elastin phase slope and increased transition strain compared to the fresh control. However, the treatment did not impair tissue strength. Decellularized intact roots presented complete leaflet competence under systemic pressures, increased dilation and effective orifice areas, reduced pressure gradients, physiological leaflet kinematics and reduced leaflet deformation.


CONCLUSIONS
The excellent leaflet kinematics and hydrodynamic performance of the decellularized roots, coupled with the excellent biomechanical characteristics of their aortic wall, form a promising platform for the creation of an acellular valve scaffold with adequate mechanical strength and functionality to accommodate dynamic cell repopulation in vitro or in vivo. This approach can be used for both allogeneic and xenogeneic tissue matrices.
Korossis
Sotirios A
SA
Institute of Medical and Biological Engineering, University of Leeds, Leeds, UK. s.korossis@leeds.ac.uk
Wilcox
Helen E
HE
Watterson
Kevin G
KG
Kearney
John N
JN
Ingham
Eileen
E
Fisher
John
J
D000818:Animals; D001021:Aortic Valve; D001696:Biomechanical Phenomena; D001705:Bioprosthesis; D004106:Dilatation; D006350:Heart Valve Prosthesis; D007038:Hypotonic Solutions; D008422:Materials Testing; D011312:Pressure; D011673:Pulsatile Flow; D012212:Rheology; D012967:Sodium Dodecyl Sulfate; D013501:Surface-Active Agents; D013552:Swine; D013718:Tensile Strength; D023822:Tissue Engineering / Q000379:methods; D014021:Tissue Preservation / Q000379:methods*; D014357:Trypsin
D007038:Hypotonic Solutions; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D014357:Trypsin