Tissue engineering of cardiac valve prostheses II: biomechanical characterization of decellularized porcine aortic heart valves.
OBJECTIVE
For both young patients with congenital heart disease and young, growing adults there is a need for replacement heart valves that will develop with the patient. Tissue-engineered heart valves coupled with in-vitro recellularization have this potential. One approach is to use acellular tissue matrices, but the decellularization treatment must not affect the biomechanical integrity of the valvular matrix. This study investigated the effect of 0.03% (w/v) and 0.1% (w/v) sodium dodecyl sulfate (SDS) on the mechanical integrity of porcine aortic valve leaflets.


METHODS
Left coronary porcine leaflets were treated with SDS (0.03% or 0.1%, w/v) in hypotonic or isotonic buffer and buffer alone. SDS in hypotonic buffer produced accellularity. Circumferential and radial specimens of treated leaflets were subjected to uniaxial tensile testing, and the effect of the buffer on leaflet morphology was assessed. Whole porcine aortic roots were also treated with 0.1% (w/v) SDS and subjected to function testing.


RESULTS
SDS treatment significantly increased extensibility of the leaflet specimens, which was greater in the circumferential than radial direction. This was seen as a significantly decreased slope of both the elastic and collagen phases of the stress-strain behavior. The ultimate tensile strength and transition stress were not affected significantly; nor was there any significant difference between hypotonic buffer and hypotonic buffer + SDS treatments. Study of the leaflet morphology suggested that the increased extensibility was due to shrinkage as well as to increased hydration of the treated leaflets caused by the hypotonic buffer.


CONCLUSIONS
SDS treatment produced a more extensible tissue with equal strength compared with the fresh aortic valve. Functionality experiments with SDS-treated whole aortic roots showed complete valve leaflet competence under physiological pressures (120 mmHg) as well as physiological leaflet kinematics.
Korossis
Sotiris A
SA
School of Mechanical Engineering, University of Leeds, UK.
Booth
Catherine
C
Wilcox
Helen E
HE
Watterson
Kevin G
KG
Kearney
John N
JN
Fisher
John
J
Ingham
Eileen
E
D000818:Animals; D001021:Aortic Valve / Q000166:cytology*; D001696:Biomechanical Phenomena; D001705:Bioprosthesis; D002478:Cells, Cultured; D006350:Heart Valve Prosthesis; D023421:Models, Animal; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013552:Swine; D013718:Tensile Strength; D023822:Tissue Engineering / Q000379:methods*