Cryopreserved Heart Valves with Repaired Matrix Metabolism

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 13671392
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Thoracic surgery
• Research Institution: The University of Tokushima
• Principal Investigator: KITAGAWA Tetsuya The University of Tokushima University Hospital, Professor, 医学部附属病院, 教授 (80240886)
• Co-Investigator(Kenkyū-buntansha): KITAICHI Takashi The University of Tokushima University Hospital, Research Associate, 医学部附属病院, 助手 (20335813) ; HORI Takaki The University of Tokushima University Hospital, Associate Professor, 医学部附属病院, 助教授 (20263832)
• Project Period (FY): 2001 – 2002
• Keywords: cryopreserved / matrix / metabolism / fibroblast / endothelium / culture / mitochondrial debydrogenase activity / cytosolic esterase activity

Research Abstract

Backgrounds: Durability oh the cryopreserved valves has heard of depending on the fibroblast viability, which can remodel the matrix assembly. Our previous study suggests the possibility that the cryopreervation and thawing process cause the inevitable damage of endothelium and fibroblast, the collagenoltic activation and the latent degradation of collagen synthesis in a cryopreserved valve,which lead to the destruction of the valve matrix.
Objective: The present investigation was to undertaken to examine whether the tissue culture of cryopreserved allograft valves after thawing would recover the cellular viability and matrix matabolism of them at the level of fresh valves or not.
Methods: Human umbilical vein endothelial cells (HUVECs) and the porcine semilunar valves were frozen with a programmed freezer, and then immediately immersed in the vapor phase of a liquid nitrogen freezer (-196℃), After 1-14 days of storage, the specimens were thawed immediately,and cultured for 1-14 days. Th e specimens were analyzed based on the cytosolic esterase activity, the mitochondria dehydrogenase activity, and the nitric oxide production. The valves were observed by confocal laser microscopic scanning.
Results: 1. Cryopreserved sparsely populated HUVECs in a dish spread all over after 2-week culture, and the mitochondrial dehydrogenase activity and nitric oxide production of cultured HUVECs were recovered at the level of those of fresh HUVECs. 2. Rich viable cells were observed in the cultured porcine valves by confocal laser microscopic scanning, and the mitochondrial dehydrogenase activity of the cultured valves was recovered.
Conclusion: This study demonstrated that the heart valve damaged seriously during the cryopreservation and thawing process was repaired for 2-week tissue culture and became viable as same as fresh valves. Further examination for the antithrombogenicity and the immunogenicity of the repaired viable valve after implantation will be necessary to improve the allograft preservation for better clinical use.