Acellular Perfusion of Porcine Kidneys: Lessons Learned.

Introduction Hypothermic machine perfusion (HMP) represents the standard of care for preservation of DCD kidneys. However, during HMP kidneys remain O2 deprived and cold temperatures are injurious. Ex-vivo normothermic machine perfusion (NMP) is an emerging technology given that providing the graft with O2 and nutrients at physiologic temperatures can prevent both cold temperatures and hypoxia. The aim of this study is to describe our initial results of ex-vivo NMP in a porcine model using an acellular plasma-like perfusate (Steen solution, SS). Methods Six kidneys underwent cold and warm ischemia times ranging from 30-180 and 15-35 min, respectively. Organs were connected to a circuit comprised of a roller pump, an oxygenator, a heat exchanger and heater set at 39°C. Nutrients and anticoagulation were provided. The circuit was run with SS (n=2) for 8 hrs, or SS with packed RBCs (n=4) for 12 hrs. Hemodynamics were monitored, and biopsies obtained at regular intervals. Results Perfusion with SS ± pRBCs showed physiologic flows during perfusion, with low resistance. Target physiologic flows were reached at subphysiologic perfusion pressures (<50mmHg).Figure: No Caption available.Histology at the end of perfusion indicates better preservation in the SS group compared to the SS+pRBC group. After 8hrs of NMP with SS intact tubular cells and a preserved brush border was seen. At the end of the 12-hr perfusion with SS+pRBCs several cells were missing nuclei. Several necrotic nuclei were also present and the tubules were beginning to lose their morphology.Figure: No Caption available.Conclusion NMP with SS ± pRBCs is capable of maintaining physiologic flows with low resistance. Furthermore, kidneys perfused with SS show satisfactory renal architecture. Organ preservation with SS could serve as a powerful platform for organ preservation and resuscitation.