An Ex-Vivo Model for Hypothermic Pulsatile Perfusion of Porcine Pancreata: Hemodynamic and Morphologic Characteristics

Abstract

Objectives: Hypothermic machine perfusion is a well-established preservation method for kidneys that allows for better preservation over longer periods and pretransplant assessment of graft viability. This technique has only sporadically been used for pancreatic grafts. The aim of this study was to establish a hypothermic machine perfusion model for porcine pancreas perfusion.

Materials and Methods: Fifteen porcine pancreata were subjected to 25 minutes of warm ischemia and 149 minutes of cold ischemia before undergoing meticulous bench work preparation and perfusion, via an aortic segment, on the RM3 perfusion machine with University of Wisconsin (Barr Laboratories Inc., Pomona, NY, USA) solution. Perfusion variables (°C, temperature; mm Hg, systolic perfusion pressure; mL/min, flow volume; mm Hg/mL/min, resistance) were recorded every 30 minutes. Tissue samples were assessed for each pancreas preperfusion and postperfusion using a semiquantitative scoring scale to grade histopathologic changes: acinar cell damage (0-4), islet cell damage (0-3), inflammation (0-3), and edema (0-3).

Results: Hypothermic machine perfusion time was set at 315 minutes, and all grafts were maintained between 4-10°C. The results were as follows (range, mean ± SD): systolic perfusion pressures were 5-13 mm Hg (9.61 ± 3.25 mm Hg) during the first 60 minutes (priming), and 15-23 mm Hg (21.07 ± 4.26 mm Hg) during the maintenance period. Target flow volumes reached 141-152 mL/min (147.6 ± 8.969 mL/min) at 60 pulses per minute. Intrapancreatic resistance decreased throughout priming to 0.03-0.09 mm Hg/mL/min (0.083 ± 0.042 mm Hg/mL/min), and remained unchanged until completion of perfusion. Pancreatic weight increase varied from 3.2% to 18.3% (13.36% ± 4.961%). There was significant postperfusion reduction in islet and acinar cell damage (P = .001 and P = .01 respectively).

Conclusions: We have developed a model of machine perfusion for porcine pancreata which is simple, reliable, and protects graft histopathologic integrity. The model can be used in further studies to improve the quality of pancreas preservation, and assess and improve the viability of the condition of borderline pancreatic grafts.