Pancreas and islet transplantation31-Phosphorus Magnetic Resonance Spectroscopy for Dynamic Assessment of Adenosine Triphosphate Levels in Pancreas Preserved by the Two-Layer Method

Cold preservation injury influences islet graft function. Reliable tools for real-time assessment of pancreas viability before islet isolation are lacking. Phosphorus magnetic resonance spectroscopy (31P-MRS) was used immediately after organ harvest to study rat pancreases at 4°C to 6°C in five randomized preservation groups: Marshall's solution, static two-layer method (TLM), continuous TLM with oxygen perfused at 0.5 L/min, and static TLM or continuous TLM both the latter following 30 minutes of warm ischemia (WI). 31P spectra were analyzed for phosphomonoesters, inorganic phosphate (Pi) and α-, β-and γ-nucleotide triphosphate. Intergroup rates of change of [γ-adenosine triphosphate (ATP)]/[Pi] and [β-ATP]/[Pi] throughout preservation period were significantly different. For continuous TLM there was an increase relative to baseline (0.043 (SD0.033) h−1 and 0.029 (0.029) h−1, respectively) but a decrease for both static TLM (−0.023 (0.016) h−1 and 0.015 (0.026), P < .001 and < .05, respectively) and Marshall's (−0.049 (0.025) h−1 and −0.036 (0.019) h−1, respectively, both P < .001) with respect to continuous TLM. Rate of decrease was similar for the Marshall's and static TLM groups. [γ-ATP]/[Pi] and [β-ATP]/[Pi] increased with WI continuous TLM (0.008 [0.009] h−1 and 0.007 [0.008] hr−1, respectively) but decreased for WI static TLM (−0.018 (0.008) h−1 and −0.014 (0.004) hr−1, respectively, P < .001). 31P-MRS is an effective tool for noninvasive assessment of pancreas bioenergetics. Continuous TLM preserves cellular bioenergetics and is superior to current non-perfluorocar bone based solutions for pancreas preservation.