The effect of cryopreservation on parathyroid cell viability and function.
BACKGROUND
Higher failure rates have been reported with cryopreserved versus fresh parathyroid autografts. The purpose of this study was to investigate the effects of cryopreservation on live cell yield and to determine if freezing tissue as dispersed cells could improve functional outcome.


METHODS
Live cell yield and cytosolic calcium (Ca[i]) and parathyroid hormone (PTH) responses to extracellular calcium were investigated prior to and after 1 to 52 weeks of cryopreservation of bovine parathyroid tissue fragments (group I) or dispersed cells (group II). Tissue was frozen using a liquid nitrogen freezer.


RESULTS
A 70% to 90% reduction in live cell yield was observed in groups I and II (P > 0.05), and this was unrelated to duration of cryopreservation. Cytosolic calcium and PTH responses to extracellular calcium in group I were similar to controls. In group II, transient Ca(i) responses were abolished, steady-state Ca(i) responses were blunted (P < 0.05), and PTH secretion was higher than in controls (P < 0.05).


CONCLUSIONS
Cryopreservation decreases live cell yield independent of length of storage. Freezing dispersed parathyroid cells produces functional abnormalities in Ca(i) and PTH regulation. Maximizing the amount of tissue for cryopreservation may improve the yield of live cells and the success rate of cryopreserved parathyroid autografts.
McHenry
C R
CR
Department of Surgery, MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio 44109-1998, USA.
Stenger
D B
DB
Calandro
N K
NK
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D015925:Cryopreservation; D006085:Graft Survival; D006801:Humans; D010280:Parathyroid Glands / Q000166:cytology / Q000502:physiology / Q000637:transplantation; D010281:Parathyroid Hormone / Q000378:metabolism; D013997:Time Factors; D014182:Transplantation, Autologous
D010281:Parathyroid Hormone; D002118:Calcium