PROTEOMIC ANALYSIS OF MACHINE PERFUSION SOLUTION FROM BRAIN DEAD DONOR KIDNEYS REVEALS THAT COMPLEMENT ACTIVATION IS ASSOCIATED WITH 1-YEAR OUTCOME

Current strategies to assess donor kidney quality are based on clinical scores or require biopsies for histological assessment. Non-invasive strategies to identify and predict graft outcome at an early stage are therefore needed. Our aim was to evaluate the secretome in non-oxygenated hypothermic machine perfusion (HMP) perfusate of donation after brain death (DBD) kidneys by comparing proteomic profiles of good outcome (GO) and ¬suboptimal outcome (SO) 1-year post transplantation. Samples taken 15 minutes after start of HMP (T1) and before termination of HMP (T2) were analysed using liquid chromatography tandem mass spectrometry (LC MS/MS). Hierarchical clustering of the 100 most abundant proteins showed discrimination between grafts with a GO and SO at T1. Upregulated expression of proteins involved in classical complement activation at both T1 and T2, and downregulated expression lipid metabolism at T1 and of cytoskeletal proteins at T2 in GO vs. SO was observed. ATP-citrate synthase and fatty acid binding protein 5 (T1) and immunoglobulin heavy variable 2-26 and Desmoplakin (T2) showed 91% and 86% predictive values respectively for transplant outcome. This study shows that the secretome of DBD kidneys can distinguish between outcome 1-year post transplantation. Furthermore, it provides insights into mechanisms that could play a role in post- transplant outcomes.

当前评估供肾质量的策略多基于临床评分，或需通过活检开展组织学评估，因此亟需能够早期识别并预测移植物预后的非侵入性策略。本研究旨在通过比较脑死亡后捐献（DBD）肾脏在无氧低温机器灌注（HMP）期间的灌注液分泌组，分析移植后1年时良好预后（GO）与欠佳预后（SO）组的蛋白质组谱差异。我们对灌注开始后15分钟（T1）及灌注终止前（T2）采集的样本，采用液相色谱-串联质谱（LC MS/MS）进行分析。对丰度最高的100种蛋白质进行层级聚类后发现，T1时间点即可区分GO与SO组移植物。相较于SO组，GO组在T1与T2时间点均存在经典补体激活相关蛋白的表达上调，且T1时间点脂质代谢相关蛋白表达下调、T2时间点细胞骨架蛋白表达下调。ATP-柠檬酸合酶与脂肪酸结合蛋白5（T1时间点）、免疫球蛋白重链可变区2-26与桥粒斑蛋白（T2时间点）分别对移植预后展现出91%与86%的预测价值。本研究证实，DBD肾脏的分泌组可区分移植后1年的预后结局，同时为移植后预后相关机制的研究提供了新见解。