Hyperbaric oxygenation of UW solution positively impacts on the energy state of porcine pancreatic tissue

BACKGROUND: Pancreatic islet transplantation is a promising option for the treatment of diabetic patients; xenotransplantation of porcine islet cells would be a possibility to overcome the shortage of donor organs. Usually the donor pancreas is preserved with University of Wisconsin (UW) solution. A large number of reports have shown that the two-layer method (TLM), which employs oxygenated perfluorochemical and UW solution, is superior to simple cold storage. However, the extensive use of TLM is cost intensive and there is evidence that TLM only oxygenates small parts of the organ preserved. Another possibility to increase the oxygen supply during organ preservation would be the use of hyperbaric oxygenation (HBO) which increases the oxygen tension in fluids. The aim of this study was to evaluate the effect of pre-oxygenation of different preservation solutions on organ quality in terms of high energy phosphate levels as well as the occurrence of apoptosis and the induction of heat shock proteins and nitrosative stress induced cell death in porcine pancreatic tissue. METHODS: Porcine pancreatic tissue was preserved in different preservation solutions with or without pre-oxygenation for 6 hours of cold ischemic time (CIT). Then, tissue specimens were harvested and high energy phosphate levels were determined by HPLC. Moreover, immunohistochemistry was performed in order to detect occurrence of apoptosis, heat shock protein 70 (HSP70) as well as nitrosative stress induced cell death. RESULTS: Organs stored in pre-oxygenated UW solution showed best results in terms of high energy phosphate levels; apoptotic cells per islet as well as HSP70 positivity were significantly less when compared to simple UW storage and all other organ preservation solutions with or without pre-oxygenation. CONCLUSIONS: Pre-oxygenation of UW solution is a simple and promising method to improve islet cell quality after cold organ storage. However, further in vitro experiments have to be performed in order to confirm these findings.