Introduction Kidneys from donation after circulatory death (DCD) donors are more susceptible to cold storage (CS) injury and have a high risk of delayed graft function (DGF). This trial is the first to compare normothermic machine perfusion (NMP) to conventional CS in DCD kidney transplantation. Methods In a multicentre randomised control trial, DCD kidneys were randomised to either NMP or CS. NMP kidneys were perfused for 60min with an oxygenated red-cell-based solution (36.0°C) The primary end point was DGF defined as the requirement for dialysis in the first 7days post-transplant. Secondary outcome measures included renal function up to 12 months posttransplant and patient/ graft survival. For all outcome measures a logistic regression model was used adjusted for cold ischaemic time, donor age, left/right kidney and centre. Results February 2016-March 2020, 338 kidneys were randomised into the trial. Twenty-five kidneys did not undergo NMP due to logistical/technical difficulties but were included in an intention-to-treat analysis. Twenty-seven kidneys in the NMP and 21 in the CS group where not transplanted and excluded; 143 NMP and 147 CS kidneys were analysed. There was no significant difference in the rate of DGF (NMP 61% vs CS 58%; P=0.624). Secondary outcome measures demonstrated a significantly higher creatinine reduction ratio day 2(CRR2) (P=0.035) and significantly lower levels of serum creatinine across all timepoints in the NMP group (P=0.024). Conclusion A short end period of NMP did not reduce rates of DGF in DCD kidneys. Secondary outcome measures suggest that NMP may improve renal function. Take-home message This is the first randomised controlled trial of normothermic machine perfusion (NMP) in clinical transplantation. The results suggest that NMP may improve the renal function of DCD kidneys.

Recent changes in surgical training coupled with increased specialisation of surgeons have led to reduced exposure for trainees to general and emergency surgery. We conducted a survey of all current general surgical trainees in the East of England to ascertain levels of experience and extent of training in dealing with major intra-operative haemorrhage during surgery. The findings confirmed that trainees lack exposure to and training in this area. Respondents were keen to see improvements in the existing training pathway and the majority were supportive of the establishment of a live large animal course in the UK as part of the solution.

Introduction Normothermic machine perfusion (NMP) of kidneys, using an oxygenated red blood cell (RBC) based solution has been developed to restore cellular metabolism and minimise effects of cold ischaemia. During NMP RBCs become damaged releasing haem activating inflammatory signalling pathways. This study aimed to measure levels of haem during NMP and determine the association with perfusion parameters and transcriptional changes in gene expression. Methods Levels of haem were measured in the perfusate before and after 1h NMP in 43 transplanted and 15 research human kidneys. Levels of haem were correlated with the age of RBCs and parameters during NMP. Human research kidneys were used to examine the changes in transcriptional gene expression using Nanostring nCounter technology. Results In transplanted and research kidneys, levels of haem increased significantly (P <0.05) during NMP. Older units of pRBCs were associated with higher levels of haem, pre-/post-NMP. High levels of haem were associated with higher levels of potassium and lactate but not functional parameters during NMP. NanoString analysis demonstrated significant upregulation of 17 differentially expressed genes including those associated with apoptosis, inflammation and oxidative stress. qPCR analysis of targeted genes demonstrated increased expression of FOS (P<0.0001), IL-6 (P=0.0001), JUN (P=0.0001) and TLR-4 (P=0.035). Conclusion Older units of RBCs contain high levels of haem which increases during NMP. Although, this did not affect perfusion parameters, transcriptional analysis demonstrated significant upregulation of genes involved with apoptotic, inflammatory and oxidative pathways. Activation of these pathways may be associated with high levels of haem. Take-home message Older units of packed red blood cells release increased levels of haem during normothermic machine perfusion of kidneys. Higher levels of haem are linked to increased activation of damage pathways.

Introduction A novel strategy to overcome the constraints of ABO compatibility in solid organ transplantation is the enzymatic removal of blood group antigens using an alpha-galactosidase enzyme from Bacteroides fragilis during ex-vivo normothermic machine perfusion (NMP). Methods Human kidneys rejected for transplantation and offered for research were used in this study which was approved by the National Research Ethics committee and Research and Development office (NRES: 15/NE/0408). Blood group antigen removal using the alpha-galactosidase enzyme GH110B from B. fragilis was first investigated on formalin-fixed paraffin-embedded (FFPE) cortex sections from human kidneys of blood group B (n=5). Immunofluorescence co-staining of the blood group B antigens (isolectin GSIB4) and vascular endothelium (CD-31) was completed. A human kidney of blood group B was then treated with 0.0025mg/ml of alpha-galactosidase during 6hrs of NMP using an acellular perfusate solution. Serial biopsies taken throughout perfusion were stained and analysed for antigen removal. Results Alpha-galactosidase treatment of FFPE sections at all concentrations examined (0.0013mg/ml 0.5mg/ml) caused significant reduction of the Pearson correlation coefficient for B antigen and CD-31 co-localisation compared to the untreated control (p<0.001). Following NMP of the treated B kidney, the Pearson correlation coefficient dropped from 0.182±0.042 (pre-treatment level) to a minimum of 0.017±0.102 after 6hrs (p<0.0001), indicating a near-complete loss of the blood group antigens. Conclusion This is the first example of the enzymatic removal of type B blood group antigens from a human kidney during NMP. This strategy may have the potential to increase the pool of ABO compatible donor kidneys for transplantation. Take-home message We have shown that an alpha-galactosidase enzyme added during ex-vivo normothermic machine perfusion can be used to enzymatically remove the blood group B antigens from human kidneys, providing the first example of whole organ conversion in humans. This strategy has the potential to massively increase the pool of ABO compatible donor kidneys for transplantation.