Cold-Preservation of Pancreatic Beta Cells

Abstract

Clinical islet transplantation requires graft preservation conditions with a minimal loss in viable beta cells. The present study examines whether rat pancreatic beta cells survive a 96 h storage period at 4°C. In a single cell viability assay, less than 20% viable cells were counted after 48 h storage in physiological HAM's F10 medium; cell survival was better in the high potassium solutions UW or Collins and further improved by supplementing Collins with albumin and benzamidine (CAB - 77% viability after 96 h). Suspended beta cell aggregates were also well preserved during 4 days in CAB-4°C as judged from DNA recovery and electron microscopy. After cold-storage in CAB, beta cells exhibited a higher insulin content than after culture in HAM's F10 at 20° or 37°C, but their capacity for subsequent insulin synthesis and release was comparable. When isolated islets were stored in CAB-4°C for 96 h, they yielded slightly higher numbers of dissociated cells than after culture in HAM's F10 at 20°C. Implantation of cold stored islets from 2 donor pancreata corrected hyperglycemia in streptozotocin-diabetic rats. It is concluded that rat beta cells can be stored in a supplemented Collins solution for at least 4 days at 4°C, with preservation of initial cell number, hormone content and glucose responsiveness. During short-term periods, this new storage condition is at least equivalent to cultures at 20° or 37°C. Further studies are needed to assess any advantage for long-term storage of islet cell grafts.