Normothermic machine perfusion of ischaemically damaged porcine kidneys with autologous, allogeneic porcine and human red blood cells

Abstract

In porcine kidney auto-transplant models, red blood cells (RBCs) are required for ex-vivo normothermic machine perfusion (NMP). As large quantities of RBCs are needed for NMP, utilising autologous RBCs would imply lethal exsanguination of the pig that is donor and recipient-to-be in the same experiment. The purpose of this study was to determine if an isolated porcine kidney can also be perfused with allogeneic porcine or human RBCs instead. Porcine kidneys, autologous and allogeneic blood were obtained from a local slaughterhouse. Human RBCs (O-pos), were provided by our transfusion laboratory. Warm ischaemia time was standardised at 20 minutes and subsequent hypothermic machine perfusion lasted 1.5-2.5 hours. Next, kidneys underwent NMP at 37˚C during 7 hours with Williams' Medium E and washed, leukocyte depleted RBCs of either autologous, allogeneic, or human origin (n = 5 per group). During perfusion all kidneys were functional and produced urine. No macroscopic adverse reactions were observed. Creatinine clearance during NMP was significantly higher in the human RBC group in comparison with the allogeneic group (P = 0.049) but not compared to the autologous group. The concentration of albumin in the urine was significantly higher in the human RBC group (P <0.001) compared to the autologous and allogeneic RBC group. Injury marker aspartate aminotransferase was significantly higher in the human RBC group in comparison with the allogeneic group (P = 0.040) but not in comparison with the autologous group. Renal histology revealed glomerular and tubular damage in all groups. Signs of pathological hyperfiltration and microvascular injury were only observed in the human RBC group. In conclusion, perfusion of porcine kidneys with RBCs of different origin proved technically feasible. However, laboratory analysis and histology revealed more damage in the human RBC group compared to the other two groups. These results indicate that the use of allogeneic RBCs is preferable to human RBCs in a situation where autologous RBCs cannot be used for NMP.

Prolonged ex-vivo normothermic kidney perfusion: The impact of perfusate composition

“…The measured albumin concentration in the perfusate decreased over time during perfusion. This decrease is most likely caused by the adherence of albumin to the plastic perfusion circuit tubing and only a small amount can be attributed to the loss in the produced urine, which is also observed in other NMP studies [24]. This urinary loss of albumin may be explained by warm ischaemia-induced damage to endothelial cells with a disruption of the filter diaphragms resulting in proteinuria, which is in line with our observed levels of albuminuria during NMP [25].…”

Real-time visualization of renal microperfusion using laser speckle contrast imaging

“…The setup of the normothermic machine perfusion (NMP) was described in detail elsewhere, 13 using a centrifugal pump head (Deltastream DP3 ® , MEDOS Medizintechnik AG, Heilbronn, Germany) controlled by in-house developed software (Sophistikate ® , Labview, National Instruments, Austin, United States). 14 The software not only enables both flow and pressure directed perfusion but also allows to switch between pulsatile sinusoidal and constant flow. The temperature was regulated using a Jubalo water heating system and set at 37°C.…”

Renal Delivery of Pharmacologic Agents During Machine Perfusion to Prevent Ischaemia-Reperfusion Injury: From Murine Model to Clinical Trials

“…In order to mimic the physiologic renal IRI, pre-clinical ex vivo perfusion experiments have been carried out with whole blood. However, in the human clinical setting an NMP perfusate could never be composed of whole blood ( 171 ). Firstly, human whole blood is not easily available.…”