The effect of ouabain (inhibitor of an ATP-dependent Na+/K+ pump) on the pancreas graft during preservation by the two-layer method.

To clarify how synthesized ATP is utilized to maintain cellular integrity during preservation by the two-layer method, we examined the effect of ouabain, inhibitor of ATP dependent Na+/K+ pump, on ATP tissue levels, graft weight, and vascular endothelial cells during 48 hr preservation by the two-layer method and pancreatic tissue perfusion and graft survival after transplantation in a canine model. Ouabain treatment did not affect ATP production but prevented its utilization by the sodium pump, and actually significantly increased ATP levels and decreased the weight loss of the graft. In addition, ouabain caused a significant increase of nuclear trypan-blue staining in vascular endothelial cells and a significant decrease of pancreatic tissue perfusion at reperfusion. Consequently, the grafts did not survive. We conclude that the two-layer method allows sufficient synthesis of ATP to drive the sodium pump and maintains membrane integrity of parenchymal cells and vascular endothelial cells, thus extending the period of preserved pancreatic viability.