title: Size of pancreatic islets of Langerhans: a key parameter for viability after cryopreservation.
abstract: Large amounts and excellent viabilities of pancreatic islets are prerequisites for recent advances in islet transplantation. Cryopreservation has been shown to enlarge transplanted cell mass, but has been accompanied by reduced viability. In this study rat pancreatic islets were differentiated into small (<200 micro m), medium (200-400 micrometers) and large (>400 micrometers) categories and their susceptibilities to different freezing conditions were evaluated: concentration of cryoprotectant (0.7-3.1 M), equilibration (15 vs. 45 min, 22 degrees C vs. on ice) and post-thaw removal of cryoprotectant (15 vs. 30 min, stepwise vs. one-step). The most prominent finding was a negative correlation between islet size and viability observed in non-frozen islets to a minor degree (r=-0.44) and significantly enhanced after cryopreservation (r<-0.8). The concentration of cryoprotectant showed the most significant influence on viability affecting small, medium and large islets. Different techniques of equilibration with the cryoprotectant resulted in significant changes of islet viability of medium islets, whereas small and large islets were unaffected. For different techniques of removal of the cryoprotectant, no significant influence on viabilities was found. We conclude that large islets represented a highly susceptible population concerning damage due to cryopreservation.
authors: Second Medical Department, University of Mainz, Germany.
authors: M A
authors: MA
authors: von Mach
authors: J
authors: J
authors: Schlosser
authors: M
authors: M
authors: Weiland
authors: P J
authors: PJ
authors: Feilen
authors: M
authors: M
authors: Ringel
authors: J G
authors: JG
authors: Hengstler
authors: L S
authors: LS
authors: Weilemann
authors: J
authors: J
authors: Beyer
authors: P
authors: P
authors: Kann
authors: S
authors: S
authors: Schneider
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D048429:Cell Size; D002470:Cell Survival; D015925:Cryopreservation / Q000379:methods*; D007515:Islets of Langerhans / Q000166:cytology* / Q000378:metabolism; D008297:Male; D010179:Pancreas / Q000166:cytology / Q000502:physiology; D010180:Pancreatectomy; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D014021:Tissue Preservation
chemical_list: D000255:Adenosine Triphosphate