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.

INTRODUCTION:Organ preservation quality impacts porcine islet cell isolation and transplantation success. Among several preservation methods, the two-layer method is promising, but technically demanding and fails to deliver sufficient oxygen. The use of hyperbaric oxygenation may be an easier, more effective method to supply high partial pressure of oxygen (pO(2)) for organ storage. Therefore, the aim of this study was to test the capability of preoxygenation of various preservation solutions with HBO to maintain high pO(2) levels.METHODS:University of Wisconsin (UW), Custodiol, Perfadex, or Celsior solutions were preoxygenated in a pressure chamber. NaCl served as the control. pO(2) levels were measured at defined times. The oxygen storage capability was evaluated by leaving the storage bottles open for 2 minutes.RESULTS:It was feasible to preoxygenate preservation solutions. The best solution to maintain high pO(2) tensions was Perfadex, followed by Celsior, and UW.DISCUSSION:The greater the amount of oxygen in the preservation solution, the more oxygen can be delivered to the preserved pancreas. Further studies on the influence of preoxygenated preservation solutions on the porcine pancreas are warranted to improve organ quality, porcine islet cell isolation, and transplantation success.

Introduction. Mechanical stress and reagents used during the isolation and purification process as well as digestion time and temperature can alter the success of porcine islet cell (PIC) isolation. This study aimed to characterize the occurrence of isoprostanes during PIC isolation using a modified automated Ricordi method and to evaluate their influence on PIC isolation outcome.Methods. Porcine pancreatic tissue was harvested at the local slaughter house, and 10 PIC isolations were performed using a modified automated Ricordi method. As positive controls for tissue damage-associated oxidative stress, six consecutive PIC isolations were performed in the presence of 1 mu g lipopolysaccharide (LPS). PLC were purified by density gradient centrifugation using the Lymphoprep density gradient. Isoprostane measurement was performed using enzyme-linked immunosorbent assay.Results. The final yield of viable and pure PICs in the experimental group was 3479 +/- 542 IEQ/g pancreas, and the LPS group yielded lower cell numbers compared to the experimental group. Isoprostane levels were significantly elevated in the LPS group as compared to the experimental group at all time points during the isolation from the beginning of the digestion process.Discussion. PIC isolation and purification results significantly differed in the two experimental groups, underlining the negative effects of oxidative stress on PIC viability and purity, which impact negatively on PIC transplantation success.

Introduction. Several studies have been carried out investigating different preservation methods and preservation solutions for the pancreata of various species. Attention has to be drawn to the extreme vulnerability of porcine pancreata (PP) to oxidative stress due to the lack of endogenous antioxidants. This study sought to evaluate the influence of cannulation and infusion of different volumes of University of Wisconsin (UW) solution immediately after organ retrieval on PP organ quality.Methods. PP from 24 slaughterhouse pigs were harvested with immediate cannulation of the pancreatic duct for infusion of 10 mL, 20 mL, 50 mL, or 100 mL UW solution. The organs were stored in cold UW solution. Control organs were only stored in UW. After 6 hours of cold ischemia, tissue and supernate samples were analyzed for markers of oxidative cell damage, adenosine triphosphate (ATP) levels, and occurrence of apoptosis.Results. The fewest apoptotic cells were detected in the PP infused with 50 mL UW via the pancreatic duct (PP 50) as compared with all other groups. Oxidative cell damage was lowest and ATP levels were highest in the PP 50 group.Discussion. Because PP 50 showed significantly better results when compared with all other groups, we suggest that infusion of 50 mL UW via the pancreatic duct immediately after organ retrieval may be useful to minimize oxidative cell damage and cell death in PP.