BACKGROUND: Optimized conditions for survival and function of @entity1 islets must be defined if sufficient islets are to be recovered from a single @entity1 donor pancreas to reverse type-1 @entity6 after isolation, cryopreservation, and transplantation. The objective of this study was to compare the cryoprotective effect of @entity10977 (EG) with the standard cryoprotectant, @entity3733 ( @entity3733 ), on isolated @entity1 islet survival and function. Furthermore, the effect of different addition protocols and equilibrium concentrations of the cryoprotectants were studied. METHODS: Islets were isolated from @entity1 pancreata by using standard techniques of collagenase digestion and discontinuous Ficoll gradient purification. Aliquots of freshly isolated @entity1 islets were cryopreserved in six groups by using @entity3733 or EG. Cryoprotectants were added stepwise to produce a final concentration of 1.5 or 2.0 M, or added in a single step to a concentration of 1.5 M. Islets were cryopreserved by using established protocols and cultured for 48 hr at 37 degrees C before assessment of percentage of recovery and in vitro viability. RESULTS: After cryopreservation, percentage of recovery of islets was significantly higher in the group treated with 1.5 M of @entity3733 added in a stepwise protocol (74+/-3%, mean+/-SEM) compared with the standard 2.0 M of @entity3733 (62+/-4%) (P<0.05, unpaired t test, n=6). There was no difference between the recovery of islets cryopreserved with either 1.5 M of @entity3733 stepwise (74+/-3%) or 1.5 M of @entity3733 one-step (69+/-3%). Islet recovery was higher in groups treated with @entity3733 compared with EG, regardless of concentration of cryoprotectant or addition protocol, although the difference was significant only when comparing @entity3733 and EG 1.5 M one-step. Furthermore, islets treated with 1.5 M of @entity3733 , added either stepwise (6.0+/-0.4) or in one-step (6.5+/-0.8), had significantly higher stimulation indices compared with islets treated with the standard cryoprotectant for @entity1 islets, 2.0 M of @entity3733 (4.5+/-0.5) (P<0.05). CONCLUSIONS: These results demonstrate that a lower concentration of @entity3733 (1.5 M) allows for the cryopreservation of @entity1 islets with superior survival and preservation of function post-culture compared with 2.0 M of @entity3733 and various concentrations of EG.

Novel approaches to cryopreservation of XXXX pancreatic islets.

@entity1 :: ('9606', 'Species') :: ['human'] @entity10977 :: ('MESH:D019855', 'Chemical') :: ['ethylene glycol'] @entity3733 :: ('MESH:D004121', 'Chemical') :: ['dimethyl sulfoxide', 'DMSO'] @entity6 :: ('MESH:D003920', 'Disease') :: ['diabetes']
@entity1 :: (9606,Species) :: ['human']
