title: Effects of cryopreservation, decellularization and novel extracellular matrix conditioning on the quasi-static and time-dependent properties of the pulmonary valve leaflet.
abstract: Decellularized allografts offer potential as heart valve substitutes and scaffolds for cell seeding. The effects of decellularization on the quasi-static and time-dependent mechanical behavior of the pulmonary valve leaflet under biaxial loading conditions have not previously been reported in the literature. In the current study, the stress-strain, relaxation and creep behaviors of the ovine pulmonary valve leaflet were investigated under planar-biaxial loading conditions to determine the effects of decellularization and a novel post-decellularization extracellular matrix (ECM) conditioning process. As expected, decellularization resulted in increased stretch along the loading axes. A reduction in relaxation was observed following decellularization. This was accompanied by a reduction in glycosaminoglycan (GAG) content. Based on previous implant studies, these changes may be of little functional consequence in the short term; however, the long term effects of decreased relaxation and GAG content remain unknown. Some restoration of relaxation was observed following ECM conditioning, especially in the circumferential specimen direction, which may help mitigate any detrimental effects due to decellularization. Regardless of processing, creep under biaxial loading was negligible.
authors.affiliation: Cardiac Surgery Research Laboratories of the Ward Family Center for Congenital Heart Disease, Children's Mercy Hospital and Clinics, Kansas City, MO 64108, USA. glconverse@cmh.edu
authors.forename: Gabriel L
authors.initials: GL
authors.lastname: Converse
authors.forename: Matt
authors.initials: M
authors.lastname: Armstrong
authors.forename: Rachael W
authors.initials: RW
authors.lastname: Quinn
authors.forename: Eric E
authors.initials: EE
authors.lastname: Buse
authors.forename: Michael L
authors.initials: ML
authors.lastname: Cromwell
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Moriarty
authors.forename: Gary K
authors.initials: GK
authors.lastname: Lofland
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Hilbert
authors.forename: Richard A
authors.initials: RA
authors.lastname: Hopkins
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology; D001807:Blood Vessel Prosthesis; D002152:Calorimetry, Differential Scanning; D015925:Cryopreservation / Q000379:methods*; D005109:Extracellular Matrix / Q000378:metabolism*; D066298:In Vitro Techniques; D008422:Materials Testing; D011664:Pulmonary Valve / Q000166:cytology* / Q000502:physiology*; D012756:Sheep; D013997:Time Factors