|Budget Amount *help
¥5,300,000 (Direct Cost : ¥5,300,000)
Fiscal Year 1997 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1996 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1995 : ¥3,300,000 (Direct Cost : ¥3,300,000)
For clinical islet cell transplantation, short term sotrage of islet cell is likely to be necessary, and it is imperative that islet cell keeps to be as viable as possible during the period. However, there are little data on which preservative solutions are most suitable for the storage of islet cell after isolation or before transplantation.
We noticed c-AMP is a fundamental second messenger in all mammalian cells, and measured c-AMP production of islet cell using a newly developed fluorometric assay under basal and stimulated conditions as a functional marker of cell viability.
Islets prepared from Lewis rat were stored for different periods of time (fresh, 3,16,24,48,96 hours) and in different preservative solutions. The stimulated adenylylcyclase activities of UW (University of Wisconsin) solution were 60.8(]SY.+-。[)13.8,86.6(]SY.+-。[)17.5,77.5(]SY.+-。[)16.2,69.8(]SY.+-。[)17.8,45.5(]SY.+-。[)18.8, and 33.5(]SY.+-。[)15.7 fmol/min/islet, respectively. Stimulated adenylylcyclase activiti
es of isolated islets stored with Euro-Collins (EC) and Lactate-Ringer (LR) solutions for 3 hours were 63.3(]SY.+-。[)20.3 and 53.3(]SY.+-。[)16.8 fmol/min/islet, respectively. Adenylylcyclase activity of UW solution was significantly higher than that of EC and LR solutions through the different periods of those preservation times.
Approximately 1,000 islet cells in each preservation group of UW solution were transplanted per streptozotocin induced diabetes rat. Transplant success rate was evaluated by measuring blood glucose level and body weight. Three weeks after the transplant, all rats recovered euglycemia. Preoperative adenylylcyclase activity was correlated well with post-transplant islet cell function in a rat model of diabetes. The result suggests that differences in islet preservation time (0,3,16,24 hours) do not effect post-transplant islet cell function, and there is a good correlation between the preoperative adenylylcyclase activity and recovery rate of plasma glucose. Additional studies showed it was feasible to measure adenylylcyclase activity in human islet cells.
We conclude that the activity of adenylylcyclase can be a useful marker of islet cell viability, both experimentally and clinically. Less