Important factors in islet cell transplantation: the role of pancreatic fragments' size, pH, potassium concentration and length of intraportal infusion

Cold preservation of rat pancreatic islets just above the freezing point using University of Wisconsin solution

AIMS

To confirm whether rat islets stored at a temperature just above the freezing point using University of Wisconsin (UW) solution would remain viable for the short term.

METHODOLOGY

Rat islets were stored for 24 hours in UW solution, either at 4 degrees C or at -0.6 degrees C (just above the specific freezing point of the UW solution). After cold storage, the islets were assessed for in vitro viability by static incubation and for in vivo viability by a transplantation study. One thousand islets preserved under different conditions were injected intraportally into a streptozotocin-induced diabetic rat as an isograft. Four weeks after the transplantation, an intravenous glucose tolerance test was performed.

RESULTS

Islets stored at -0.6 degrees C showed higher insulin secretion rates than those stored at 4 degrees C on a static challenge. The interval from transplantation to the achievement of normoglycemia was also shorter in the -0.6 degrees C group than in the 4 degrees C group. After islet transplantation, the daily nonfasting plasma glucose concentration was higher in the 4 degrees C group than in the -0.6 degrees C group. When compared with the 4 degrees C group, the -0.6 degrees C group showed lower blood glucose values during all investigational periods on an intravenous glucose tolerance test.

CONCLUSION

Islet preservation at -0.6 degrees C using UW solution is more advantageous for short term.

Successful treatment of streptozotocin diabetes of the rat by transplantation of the islets from a single donor pancreas

A new digestion chamber was developed which made it possible to isolate 500 islets from the pancreas of one adult rat. The mesh chamber enabled us to remove islets out of the collagenase solution as soon as they are separated from pancreatic tissue. The islet injury due to collagenase was diminished, and the time of warm ischemia during digestion was considerably reduced. With this method it was possible to treat the diabetes successfully in eight of 14 rats. The condition of the remaining six rats was considerably improved, and no animal died due to diabetes during 90 days of surveillance as compared to a 50% death rate in the diabetic control group. A cataract did not occur in any transplanted rat, whereas it was observed in all surviving animals of the diabetic control group. If the complete separation of endocrine and exocrine tissue in a density gradient was abandoned the transplantation results improved significantly.