Mesenchymal Stromal Cell Treatment of Kidneys During Normothermic Machine Perfusion is Safe and Feasible with Effective Traceability after Transplantation

Lohmann 1/M. Pool 2, K. Rozenberg 3, M. Eijken 4, U. Møldrup 5, B.K. Møller 6, J.M. Sierra Parraga 7, M. Hoogduijn 7, L. Lo Faro 3, C. Moers 2, J. Hunter 3, A.K. Keller 1, H. Leuvenink 2, C.C. Baan 7, R.J. Ploeg 3, B. Jespersen 1 Department of Clinical Medicine, Aarhus University, Aarhus, Denmark Department of Surgery, University Medical Center Groningen, Groningen, The Netherlands Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark Department of Urology, Aarhus University Hospital, Aarhus, Denmark Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark Department of Internal Medicine, Nephrology and Transplantation, Erasmus MC, University Medical Center, Rotterdam, the Netherlands Introduction Marginal kidneys are increasingly being accepted to decrease waiting time for a transplant. Normothermic machine perfusion (NMP) is a technique that allows delivery of therapies that may help condition or repair the organ prior to transplantation. Mesenchymal stromal cells (MSC) may be able to ameliorate ischaemia reperfusion injury as they possess potent anti-inflammatory and regenerative properties. We investigated the safety and effect of MSCs administered during ex vivo NMP prior to transplantation in a pig auto-transplant model of donation after circulatory death. Methods  Porcine kidneys subjected to 75 min warm ischaemia were retrieved and preserved for 14h by oxygenated HMP (oxHMP) and 4h NMP and then auto-transplantation. Kidneys were randomised to three different intervention strategies (n=7 per group): following 1h NMP, either a vehicle (NMP), 10 million pig MSC (NMP+pMSC) or 10 million human MSC (NMP+hMSC) were intra-arterially infused. The NMP groups were all compared to a control group, where kidneys were only preserved with oxHMP. The pig was re-anaesthetised, the contralateral kidney was removed and the treated kidney was auto-transplanted and the animals were recovered for 14 days. Results Renal blood flow during NMP was no different between the groups (p=0.0685). Post-transplant plasma creatinine increased in all groups but there were no significant differences between the groups (p=0.517). Plasma kidney injury biomarker NGAL was significantly higher in the NMP+pMSC group compared to the NMP (p=0.003) and NMP+hMSC (p=0.017) groups at day 14. On day 14, mGFR significantly improved in the NMP group compared to the control (55 ± 3 vs 42 ± 12 ml/min, p=0.025). No differences in GFR were observed on day 14 in the other groups (NMP+pMSC, p=0.090 and NMP+hMSC, p=0.387). MSC were detectable in biopsies of MSC treated kidney after NMP and post-transplantation. Conclusion NMP alone improved renal graft function compared to oxHMP of DCD kidneys post-transplant. The method of MSC administration during NMP proved to be safe, however in this model MSC treatment did not improve renal function. Nevertheless viable MSC remained detectable in the transplanted kidney at postoperative day 14 which may have an effect on longer term outcomes.