PANCREAS STORAGE FOR ISLET ISOLATION

Using a large (outbred dog) and small (inbred rat) animal model and the most appropriate preservation solution (University of Wisconsin [UW] solution), we have investigated the relationship between pancreas preservation interval and islet yield and viability. Following a standard vascular flush and hypothermic storage, we found that dog islet yields were reduced by 50% after 12 hours of cold storage and that intrasplenic autograft success rates were poor. Similarly, in the rat, islet yields were reduced by more than 50% after as little as 3 hours of cold storage. However, when UW solution was delivered intraductally into the pancreas at the time of organ procurement along with the appropriate dose of collagenase islet yields could be maintained at control levels in both the dog and rat models for at least 24 hours. In addition, the intrasplenic autograft success rate at 24 hours in the dog was 100% (n=7) and the intrahepatic isograft success rate in the rat was 83% (n=7). Continuation of the preservation for 48 hours resulted in a reduction in islet yield and autograft success rate in the dog model whereas in the rat model, while there was no demonstrable reduction in islet yield, no isografts were successful. Despite the satisfactory transplant outcomes after 24 hr of cold storage using the adjusted flushing technique, there was some evidence of islet injury which was more apparent in the rat model. We conclude that standard techniques of cold storage may not be suitable for pancreatic preservation prior to islet isolation.