The mechanism of action of the two-layer (Euro-Collins' solution/perfluorochemical) cold storage method in canine pancreas preservation.

Abstract

To clarify the mechanism of action of a two-layer [Euro-Collins' solution (EC)/perfluorochemical (PFC)] cold storage method in the preservation of the pancreas, pancreatic viability and tissue concentrations of adenosine triphosphate (ATP) were examined in the canine model of pancreatic autotransplantation after preservation for 24 and 48 h by simple cold storage in EC (group 1), the two-layer, EC/PFC, method (group 2) and the two-layer, EC+2, 4 dinitrophenol (DNP)/PFC, method (group 3). DNP is an uncoupler of oxidative phosphorylation. Maintenance of normoglycemia for at least 5 days after transplantation was considered a successful preservation. After preservation for 24 h, the functional success rates of groups 1, 2 and 3 were 100% (4/4), 100% (5/5) and 80% (4/5) respectively. One of five dogs in group 3 died of a cause unrelated to the pancreas. ATP tissue concentrations in group 2 were significantly higher than in group 1 (7.47 +/- 0.47 micromol/g dry weight vs 1.41 +/- 0.53 micromol/g dry weight, P < 0.01) and ATP tissue concentrations in group 3 were significantly lower than in group 2 (1.25 +/- 0.37 micromol/g dry weight vs 7.47 +/- 0.47 micromol/g dry weight, P < 0.01). It was apparent that ATP was not an essential factor for successful 24-hour preservation of the canine pancreas in EC because all the pancreatic grafts except one of five grafts in group 3 remained viable after preservation for 24 h, regardless of ATP tissue concentrations. On the other hand, after preservation for 48 h, the functional success rates for groups 1, 2 and 3 were 0% (0/4), 100% (4/4) and 0% (0/3) respectively. ATP tissue concentrations in group 2 were significantly higher than in group 1 (7.91 +/- 1.21 micromol/g dry weight vs 1.21 +/- 0.31 micromol/g dry weight, P < 0.01) and ATP tissue concentrations in group 3 were significantly lower than in group 2 (0.61 +/- 0.07 micromol/g dry weight vs 7.91 +/- 1.21 micromol/g dry weight, P < 0.01). It was clear that preservation of the pancreas for 48 h was unsuccessful by simple cold storage in EC (group 1) and the two-layer method (group 2) made preservation for 48 h possible by increasing ATP tissue concentrations. However, DNP (group 3) inhibited the synthesis of ATP and the effectiveness of the two-layer method for 48-hour preservation of the pancreas. It was clear that maintenance of high ATP tissue concentrations during preservation was essential for the successful preservation of the canine pancreas in EC by the two-layer method for more than 48 h. We concluded that an adequate supply of oxygen to the pancreas during preservation by the two-layer method led to sufficient production of ATP to maintain cellular integrity and permitted the improvement of pancreatic preservation.