title: The effect of cryopreservation on the immunogenicity of allogeneic cardiac valves.
abstract: A proportion of implanted cryopreserved allogeneic cardiac valves (ACV) fail due to tissue degeneration initiated by immunological reactions. This study was carried out in a rat model system [Brown Norway (BN; RT1(n)) to Lewis (RT1(l))] to determine the possibility of cryoimmunomodulation of ACV. The immunogenicity of fresh and cryopreserved (1 degrees, 5 degrees, 10 degrees, 30 degrees, and >100 degrees C/min) BN aortic valve conduits (AVC) was assessed using a mixed AVC cell/responder lymphocyte reaction. No significant differences (p > 0.05) in immunogenicity between fresh and cryopreserved (1 degrees C/min and 5 degrees C/min) AVC were observed between 120 and 168 h of co-culture. A significant reduction in immunogenicity was observed with AVC cryopreserved using cooling rates of 10 degrees, 30 degrees, and >100 degrees C/min. The viability of fresh and cryopreserved AVC was determined by a [3H]proline uptake assay. A decrease in viability was observed at cooling rates of more than 1 degrees C/min. The feasibility of cryoimmunomodulation of ACV with the maintenance of viability of a proportion of cells was demonstrated.
authors.affiliation: Department of Microbiology, University of Leeds, Leeds, United Kingdom.
authors.forename: N
authors.initials: N
authors.lastname: Ketheesan
authors.forename: J N
authors.initials: JN
authors.lastname: Kearney
authors.forename: E
authors.initials: E
authors.lastname: Ingham
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation*; D001705:Bioprosthesis; D015925:Cryopreservation; D005260:Female; D006350:Heart Valve Prosthesis; D066298:In Vitro Techniques; D007959:Lymphocyte Culture Test, Mixed; D008954:Models, Biological; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D014181:Transplantation Immunology; D014184:Transplantation, Homologous