title: Comparison and evaluation of biomechanical, electrical, and biological methods for assessment of damage to tissue collagen.
abstract: In regard to evaluating tissue banking methods used to preserve or otherwise treat (process) soft allograft tissue, current tests may not be sufficiently sensitive to detect potential damage inflicted before, during, and after processing. Using controlled parameters, we aim to examine the sensitivity of specific biomechanical, electrical, and biological tests in detecting mild damage to collagen. Fresh porcine pulmonary heart valves were treated with an enzyme, collagenase, and incubated using various times. Controls received no incubation. All valves were cryopreserved and stored at -135 °C until being rewarmed for evaluation using biomechanical, permeability, and cell viability tests. Statistically significant time dependent changes in leaflet ultimate stress, (p = 0.006), permeability (p = 0.01), and viability (p ≤ 0.02, four different days of culture) were found between heart valves subjected to 0-15 min of collagenase treatment (ANOVA). However, no statistical significance was found between the tensile modulus of treated and untreated valves (p = 0.07). Furthermore, the trends of decreasing and increasing ultimate stress and viability, respectively, were somewhat inconsistent across treatment times. These results suggest that permeability tests may offer a sensitive, quantitative assay to complement traditional biomechanical and viability tests in evaluating processing methods used for soft tissue allografts, or when making changes to current validated methods. Multiple test evaluation may also offer insight into the mechanism of potential tissue damage such as, as is the case here, reduced collagen content and increased tissue porosity.
authors.affiliation: Clemson-MUSC Joint Bioengineering Program, Department of Bioengineering, Clemson University, 173 Ashley Avenue MSC 508, Charleston, SC, 29425, USA.
authors.forename: R Glenn
authors.initials: RG
authors.lastname: Hepfer
authors.affiliation: Clemson-MUSC Joint Bioengineering Program, Department of Bioengineering, Clemson University, 173 Ashley Avenue MSC 508, Charleston, SC, 29425, USA.|Tissue Testing Technologies LLC, North Charleston, SC, USA.
authors.forename: Kelvin G M
authors.initials: KG
authors.lastname: Brockbank
authors.affiliation: Tissue Testing Technologies LLC, North Charleston, SC, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Tissue Testing Technologies LLC, North Charleston, SC, USA.
authors.forename: Elizabeth D
authors.initials: ED
authors.lastname: Greene
authors.affiliation: Tissue Testing Technologies LLC, North Charleston, SC, USA.
authors.forename: Lia H
authors.initials: LH
authors.lastname: Campbell
authors.affiliation: Clemson-MUSC Joint Bioengineering Program, Department of Bioengineering, Clemson University, 173 Ashley Avenue MSC 508, Charleston, SC, 29425, USA.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Wright
authors.affiliation: LifeNet Health, Virginia Beach, VA, USA.
authors.forename: Alyce
authors.initials: A
authors.lastname: Linthurst-Jones
authors.affiliation: Clemson-MUSC Joint Bioengineering Program, Department of Bioengineering, Clemson University, 173 Ashley Avenue MSC 508, Charleston, SC, 29425, USA. haiyao@clemson.edu.
authors.forename: Hai
authors.initials: H
authors.lastname: Yao
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003094:Collagen / Q000378:metabolism*; D055119:Elastic Modulus; D004553:Electric Conductivity; D055724:Electrophysiological Phenomena; D006351:Heart Valves / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D010539:Permeability; D013314:Stress, Mechanical; D034421:Sus scrofa; D013718:Tensile Strength; D023822:Tissue Engineering / Q000379:methods*; D014022:Tissue Survival
chemical_list: D003094:Collagen
keywords: Cell viability; Cryopreservation; Heart valve; Matrix permeability; Soft tissue; Tensile modulus