Cell viability in cryopreserved heart valves (abstract)

Authors: Armiger LC
Publication: New Zealand Veterinary Journal, Volume 41, Issue 1, pp 43, Mar 1993
Publisher: Taylor and Francis

Animal type: Human
Subject Terms: Circulatory system/haematology, Cell biology, Surgery
Article class: Abstract

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Abstract: The clinical life of heart valve grafts appears to be limited primarily by the lack of a cell population which can maintain the connective tissue of the cusps, or leaflets, in good condition. Whether this problem can be overcome in allografts by ensuring that the original donor cell population is kept alive during the disinfection and storage of valves intended for grafting has long been a controversial issue.
It is generally assumed that cryopreservation will result in a “live” or “viable” implant. To establish whether this is so for valve grafts prepared by the methods currently in use at Green Lane Hospital, two series of investigations were carried out. The first was an autoradiographic study of the “viability” of cryopreserved valves immediately following the thawing process used prior to implantation. This employed tritiated glucosamine as a label to demonstrate the distribution within the valve leaflet of cells still able to synthesise proteoglycan matrix material. In 34 valves examined, label was detected only in the basal or “hinge” area of leaflets and in the adjacent supporting tissues.
The second was a detailed morphologic study of cryopreserved grafts removed from patients after 4-8 years of implantation. Most of these explanted cryopreserved valves showed some foci of active fibroblastic growth in one or more leaflets. They occurred both in the hinge area, where their origin was consistent with either donor or recipient derivation, and in distal parts of the leaflet, where they were frequently associated with infiltrates of macrophages.
These observations indicate that the fibroblasts seen in the explanted cryopreserved allograft are not solely of donor origin and are likely to be more often derived from recipient sources. Hence, pre-implantation cell viability appears not to be of major importance in valve grafting.

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