31P NMR spectroscopy for in vitro viability testing of porcine pancreatic islets.
The quality of pancreatic islets prepared by an intraductal pancreas collagenase perfusion technique was tested using three independent methods: 31P NMR spectroscopy, an insulin secretion test, and a staining method. The viability of pancreatic islet tissue was evaluated using the ratio of phosphate diester to phosphate monoester (PDE/PME) as a new criterion obtained by 31P NMR spectroscopy. According to this criterion, three types of tissue fragments could be characterized: vital (PDE/PME 0.5-0.9), damaged (PDE/PME less than 0.2), and necrotic (no PDE, no PME). The findings in the three different groups could be correlated to three trends of insulin secretion of the preparations following glucose challenge: good response to the glucose challenge, continuous decrease of insulin production, and no insulin secretion. We feel that 31P NMR spectroscopy offers a rapid and suitable method for classifying the viability of isolated pancreatic islets.