Updated project metadata. To identify the main biological effects of the normothermic machine perfusion (NMP) in marginal kidneys, we measured, by mass spectrometry analysis, changes in the proteomic profile of kidney tissues and urines of eight organs reconditioned for 120 minutes (by a Kidney Assist device). Biopsy specimens were taken at the time of the pre-implantation histological evaluation (T-1), at the start of back table preparation (T0), and after 60 (T60) and 120(T120) minutes. Urine were collected at T0, T30, T60 and T120. Several bioinformatics/statistical algorithms (including SVM and PLS-DA) were used to select the most discriminative proteins. Bioinformatics analysis showed that, during NMP, a large number of proteins resulted down- or up-regulated in the kidneys (169 and 196, respectively). SVM and PLS-DA analysis restricted this panel to 50 top-discriminative proteins. Among these, 11 proteins resulted similarly up-regulated(LXN, ETFB, NUDT3, CYCS and UQCRC1)and down-regulated after NMP treatment (CFHR3, C1S, CFI, KNG1, SERPINC1, F9)in urine.Functional analysis, then, revealed that the most up-regulated proteins were involved in the oxidative phosphorylation system (OXPHOS) and ATPsynthesis, while thoseunder-expressed were implicated in the complement and coagulation cascade.Our proteomic analysis demonstrated that NMP (also for a brief period of time) may induce substantial metabolic and biochemical changes in marginal organs. This encourages use of this technology in clinic.