Application of steroid-free immunosuppressive protocols has markedly improved outcomes in pancreatic isle 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 only 20-50% of the islets. In addition, a significant reduction of islet mass occurs in the peritransplant period. Presently, cadaver donors remain the sole source of pancreatic tissue for PIT. Unfortunately no studies have been conducted to date to determine the biological effects of BD on isolated human islets. Moreover by recommendation of the American Society of Transplant Surgeons, multiorgan donors receive triiodothyronine vasopressin, cortisol and insulin. However, no information is available regarding beneficial or detrimental effects oft human islets. Our recent studies indicate that brain-death (BD) is associated with decreased isolated islet recovery functionality, and engraftment after transplantation. Deleterious effects of BD on isolated islets could explain the major differences observed in clinical PIT outcomes compared with results routinely obtained in experimental animals. Based on the anti-inflammatory, anti-apopototic, and anti-oxidant properties of 17beta-estradiol, we previously demonstrated significant reduction of proinflammatory cytokine-mediated human islet death. In addition, our preliminary data demonstrate that estradiol administration to BD-donors increases islet recovery in rats. It is conceivable to postulate that reduction of deleterious effects of BD by 17beta-estradiol treatment to human BD donor; would mitigate islet loss, improve islet functionality and engraftment after transplantation. Our studies will examine the hypothesis that BD is associated with decreased human islet yields, viability, functionality and engraftment. To this end, islets obtained from BD-donors will be compared with islets recovered from human patients subjected to pancreatectomy for benign pancreatic tumors. In addition, we will analyze islet preparations obtained from BD-donors treated with either vehicle, estradiol or """"""""hormonal therapy"""""""". Extensive molecular studies including islet gene expression profiles using microarrays, islet protein kinases using multi-immunoblotting techniques will provide information about the molecular mechanisms involved in detrimental effects of BD and will identify potential therapeutic targets. Overall, these studies will bring novel information about human islet biology and will provide c potential therapeutic strategy to enhance the therapeutic efficacy of PIT as a cure for diabetes.
| Kelpke, Stacey S; Chen, Bo; Bradley, Kelley M et al. (2012) Sodium nitrite protects against kidney injury induced by brain death and improves post-transplant function. Kidney Int 82:304-13 |
