title: Long-term viability of cryopreserved cultured epithelial grafts.
abstract: Human cultured epithelial grafts are frozen for long-term preservation. To assess the viability of these stored grafts, their cell survival rate and colony-forming efficiency of grafts cryopreserved at -135 degrees C and at -80 degrees C were followed over time. Flow cytometry showed that the cell survival rate of the grafts cryopreserved at -135 degrees C for 1 month, 6 months and 1 year averaged 89.3%, 61.7% and 61.6%. Cryopreservation at -80 degrees C maintained cell survival rate as well for 1 month, but after 6 months of cryopreservation survival was reduced at -80 degrees C (35.2%) compared with that of -135 degrees C. In histological examination, the cell structure and basal layer were very well preserved after 6 months of storage at -135 degrees C, but not at -80 degrees C. Cell survival rate at -135 degrees C was also assessed by colony-forming efficiency. Colony-forming efficiency of the grafts cryopreserved for 1 month, 6 months and 1 year averaged 66.1%, 58.5% and 55.1% of control (noncryopreserved) grafts. These findings suggest that, even when cultured epithelial grafts are subjected to long-term cryopreservation, cell viability remains sufficient, reculturing is possible, and that graft banking could be used for clinical applications.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Kurume University School of Medicine, Kurume City, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Udoh
authors.forename: H
authors.initials: H
authors.lastname: Yanaga
authors.forename: Y
authors.initials: Y
authors.lastname: Tai
authors.forename: K
authors.initials: K
authors.lastname: Kiyokawa
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D002470:Cell Survival; D015925:Cryopreservation; D046508:Culture Techniques; D004848:Epithelium / Q000033:anatomy & histology / Q000637:transplantation*; D013997:Time Factors