title: Cryoprotective Effect and Optimal Concentration of Trehalose on Aortic Valve Homografts.
abstract: OBJECTIVE
  Cryopreservation allows for the long-term storage of aortic homografts, but a high risk of calcification and degeneration is often observed following their transplantation. The study aim was to investigate the cryoprotective effect of trehalose on aortic valve homografts preserved in liquid nitrogen, and to determine the optimal trehalose concentration for such purpose.
  
  
  METHODS
  Aortic valve homografts obtained from New Zealand White rabbits were processed using different protectants. Samples were assigned at random to four groups: a control group treated with dimethyl sulfoxide (DMSO; 0.1 mol/l), and test groups A, B and C, which were treated with 0.1 mol/l trehalose + 0.1 mol/l DMSO, 0.2 mol/l trehalose + 0.1 mol/l DMSO, or 0.3 mol/l trehalose + 0.1 mol/l DMSO, respectively, as protectant. Samples in each group were allocated randomly to three subgroups and cryopreserved for 12, 15, and 18 months, respectively. After thawing, apoptosis of the cryopreserved homograft samples was evaluated using immunohistochemistry, semi-quantitative RT-PCR and Western blotting methods. The viability of the tissue cells was assessed by monitoring glucose utilization capacity.
  
  
  RESULTS
  The apoptosis assay showed that, among the four groups and at all time points, the expression of caspase-3 was lowest in test groups A and B and highest in the DMSO group. In comparison, the glucose metabolic rates of test groups A and B were highest, while rates for test group C and the control (DMSO) group ranked second and third.
  
  
  CONCLUSIONS
  When aortic homografts are preserved in liquid nitrogen, the cryoprotective effect of trehalose combined with DMSO was superior to that of DMSO alone. The optimal trehalose concentration to cryoprotect rabbit aortic homografts was between 0.1 and 0.2 mol/l.
authors.forename: Qing
authors.initials: Q
authors.lastname: Chang
authors.forename: C Chen
authors.initials: CC
authors.lastname: Cheng
authors.forename: Hui
authors.initials: H
authors.lastname: Jing
authors.forename: C Jian
authors.initials: CJ
authors.lastname: Sheng
authors.forename: T Yi
authors.initials: TY
authors.lastname: Wang
mesh_terms: D064591:Allografts; D000818:Animals; D001021:Aortic Valve / Q000187:drug effects* / Q000378:metabolism / Q000637:transplantation / Q000648:ultrastructure; D017209:Apoptosis / Q000187:drug effects; D001705:Bioprosthesis; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D019610:Cytoprotection; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004734:Energy Metabolism / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation; D011817:Rabbits; D013997:Time Factors; D014022:Tissue Survival / Q000187:drug effects; D014199:Trehalose / Q000494:pharmacology*
chemical_list: D003451:Cryoprotective Agents; D014199:Trehalose; D053148:Caspase 3; D005947:Glucose; D004121:Dimethyl Sulfoxide