Network for Earthquake Engineering Simulation

Normothermic machine perfusion (NMP) has emerged as technology for organ preservation and assessment. While NMP has been widely adopted for liver, lung, and heart transplantation, kidney NMP has faced slower clinical integration. Normothermic perfusion may potentially improve kidney transplant through improved preservation, graft viability assessment, mitigation of ischemia reperfusion injury, and treatment prior to transplant. The purpose of this review is to highlight the applications of NMP in kidney transplantation. Kidney NMP has been proven well tolerated and feasible in multiple studies. Two recent randomized controlled trials did not demonstrate a benefit of NMP compared to cold storage. The use of NMP may increase utilization through improved logistics. Graft assessment during perfusion may allow for well tolerated transplantation of marginal kidneys. Successful long-term perfusion up to 4 days of discarded kidneys has been performed. Gene therapies and treatments, including immune modification, have been carried out during kidney NMP. Normothermic perfusion has several applications to kidney transplantation including preservation, assessment, and treatment. Perfusion protocols viability criteria need to be defined. A portable, commercially available device is needed to increase clinical use. Further studies are needed to compare NMP to current preservation methods.

Abstract Achieving efficient mRNA delivery and expression in intact solid organs beyond the liver remains a major challenge for advancing mRNA therapeutics. Normothermic machine perfusion (NMP) provides a clinically relevant ex vivo platform for targeted intervention during donor organ preservation, minimizing systemic exposure and enabling organ-confined mRNA delivery. Here, we demonstrate that intra-arterial infusion of lipid nanoparticles (LNPs) encapsulating reporter mRNAs during kidney NMP enables robust, organ-wide protein expression in human-sized porcine donor kidneys. Engineered LNP formulations were first evaluated for stability and efficacy in kidney cell lines, where LNPs pegylated with TPGS (D-α-tocopherol polyethylene glycol 1000 succinate) achieved the highest reporter protein expression levels. Next, the LNP-encapsulated mRNAs were introduced into porcine kidneys via a 5-minute infusion during NMP. mCherry and human erythropoietin (hEPO) mRNAs were delivered via the renal artery, serving as intracellular and secreted reporters, respectively. The perfusion was continued for 6-12h after LNP-mRNA infusion with the erythrocyte-based perfusate at 37 °C. LNP-mRNA administration resulted in widespread parenchymal mRNA uptake and rapid, robust reporter protein expression that continued to increase over the perfusion period. hEPO protein was detected in perfusate and urine, while mCherry expression localized to endothelial and tubular cells within the renal parenchyma. Consistent with the in vitro data, TPGS-LNPs produced the highest expression during NMP. Importantly, LNP-mediated mRNA delivery during NMP did not affect perfusion parameters or histological integrity. These findings demonstrate successful mRNA-driven protein expression in intact donor kidneys, establishing NMP as a clinically relevant route for organ-specific RNA delivery and protein expression modulation. One sentence summary Using a clinically compatible normothermic machine perfusion model, we demonstrate that lipid nanoparticle-mediated mRNA delivery enables rapid, organ-wide protein expression in human-sized porcine donor kidneys.