Proton NMR spectroscopy as a novel approach to the monitoring of citrate and trimethylamine-N-oxide excretion after kidney preservation

Abstract HIGH resolution protin nuclear magnetic resonance (NMR) spectroscopy can be used for the rapid multicomponent analysis of low molecular weight metabolites in biologic fluids such as plasma and urine. Citrate (Cit) is an organic acid normally found in human urine. Reduced urinary Cit excretion has been described in HgCl 2 and p -aminophenol intoxication. 1 The mechanism is impairment of the Krebs cycle. Trimethylamine-N-oxide (TMAO) is an osmolyte molecule synthesized in the medullar cells of the kidney. 2 In plasma and urine, TMAO is not usually detected. Its excretion may be related to leakage from the renal medulla cells after intense medullar ischemia. The aim of this study was to assess Cit and TMAO excretion after prolonged cold storage (CS) with two standard solutions. These markers are precisely detected by proton NMR spectroscopy.