Perfusate Proteomes Provide Biological Insight Into Oxygenated Versus Standard Hypothermic Machine Perfusion in Kidney Transplantation.
Mulvey JF., Ul Shaheed S., Charles PD., Snashall C., Lo Faro ML., Sutton CW., Jochmans I., Pirenne J., van Kooten C., Leuvenink HG., Kaisar M., Ploeg RJ.
OBJECTIVE: Mass spectrometry profiling of perfusate samples collected during a phase-3 randomized double-blind paired clinical trial of hypothermic machine perfusion (HMP) with and without oxygen (COMPARE) aimed to provide mechanistic insight into key biological alterations of DCD kidneys during continuous perfusion and inform about future interventions. SUMMARY BACKGROUND DATA: Despite the clinical benefits of novel perfusion technologies aiming to better preserve donor organs, biological processes that may be altered during perfusion have remained largely unexplored. Collection of serial perfusate samples during the COMPARE clinical trial provided a unique resource to study perfusate proteomic profiles, with the hypothesis that in-depth profiling may reveal biologically meaningful information on how donor kidneys benefit from this intervention. METHODS: Multiplexed liquid chromatography tandem mass spectrometry was used to obtain a proteome profile of 210 perfusate samples. Partial least squares discriminant analysis and multivariate analysis involving clinical and perfusion parameters were used to identify associations between profiles and clinical outcomes. RESULTS: Identification and quantitation of 1716 proteins indicated that proteins released during perfusion originate from the kidney tissue and blood, with blood-based proteins being the majority. Data show that overall HMP duration associate with increasing levels of a subgroup of proteins. Notably, high-density lipoprotein and complement cascade proteins are associated with 12-month outcomes and blood-derived proteins are enriched in the perfusate of kidneys that developed acute rejection. CONCLUSIONS: Perfusate profiling by mass spectrometry was informative and revealed proteomic changes that are biologically meaningful and in-part explain the clinical observations of the COMPARE trial.