Improved preservation and microcirculation with POLYSOL after transplantation in a porcine kidney autotransplantation model.

Background. The most widely used preservation method for kidney grafts is cold static storage (CS) using the University of Wisconsin (UW) solution. To date, new preservation solutions have not been able to significantly improve preservation quality of grafts. The aim of this study was to compare POLYSOL, a recently developed low viscosity preservation solution, and the UW solution for CS of porcine kidney grafts. Methods. In a porcine autotransplantation model, real-time parameters of the renal microcirculation were evaluated using the novel oxygen-to-see (O2C) combined laser Doppler and flowmetry system. Thereafter, kidneys were retrieved and washed out with POLYSOL or UW followed by 20-h CS. After the preservation period, the contralateral kidneys were removed and the preserved kidneys autotransplanted. The microcirculation was re-assessed at 10 min after reperfusion and at 7 days posttransplant, prior to removal of the grafts for histological evaluation. Results. POLYSOL was able to better preserve the microcirculation compared to UW as expressed by higher values of capillary blood flow, blood flow velocity and tissue oxygen saturation values. In addition, CS using POLYSOL resulted in improved functional recovery demonstrated by lower posttransplant serum creatinine and blood urea values in comparison to the UW group. Also, structural integrity was better preserved in the POLYSOL group, compared to UW. Conclusions. This study in a clinically relevant large animal model showed that a new preservation solution, POLYSOL, resulted in improved preservation quality of kidney grafts compared to the UW solution.