Vitrification of human islets of Langerhans.

Cryopreservation of human islets of Langerhans by vitrification was studied. Isolated islets were divided into four groups: (1) control islets which were cultured for 6 days, (2) islets which were vitrified after 2 days of culture, (3) control islets which were cultured for 10-13 days, and (4) islets which were vitrified after 6-9 days of culture. After warming, islets from groups 2 and 4 were cultured for 4 days. The thus treated islets were investigated with respect to insulin secretion in the presence of 2.5 or 25 mM glucose, capacity to survive during postwarming culture, and morphology. The insulin secretion in islets from all groups could be stimulated by an increase of the concentration of glucose from 2.5 to 25 mM. No significant differences were observed between the insulin secretions of the vitrified and control islets or between the islets vitrified after 2 and 6-9 days of culture. It is concluded that human islets of Langerhans cryopreserved by vitrification are functional in vitro.