Application of a new steroid-free immunosuppressive protocol has markedly improved outcomes in pancreatic islet transplantation (PIT). However, large numbers of islets are required to achieve insulin-independence. While approximately 1 million islets exist in the adult human pancreas, the current pancreas preservation and islet isolation techniques recover fewer than 50% of the islets. Furthermore, additional loss of islet mass occurs in the peritransplant period. Our recent studies indicate that brain-death (BD) is associated with significant reduction in human and rat islet recovery functionality, and engraftment. Islets recovered from BD-donors presented higher NF-lappaB, and JNK nuclear transcriptional activity compared with non BD-donors. In addition, hyperexpression of Bax has been demonstrated. These factors have been identified also as critical mediators of islet cell death during exposure to PIC, oxidative, ischemic, osmotic, and mechanical stress, all inherent of PIT. Unfortunately, until today, no studies have been conducted to prevent/decrease deleterious effects of BD on PIT. One of the most recent and promising technologies available to manipulate gene expression is RNA interference, a technique that allows specific silencing of genes by delivering highly homologous RNA into the cell. The efficacy of this technology has been demonstrated in vitro in different cell types including islets, and more recently in vivo. Therefore, we hypothesize that down-regulation of islet specific expression of NF-kappaB, JNK, and Bax RNA before pancreas procurement will decrease the deleterious effects of BD on PIT. In view of this, we propose to evaluate if in situ specific islet inhibition of NF-kappaB, JNK-1, and Bax before pancreas procurement using siRNA will enhance rat isolated islet recovery, functionality, and engraftment from brain-death donors. The proposed studies are expected to yield novel information about the effects of BD on isolated islet biology and to develop potential targets for therapeutic intervention, thereby enhancing the efficacy of PIT as a cure for diabetes.
