Use of serum and urine metabolome analysis for the detection of metabolic changes in patients with stage 1-2 chronic kidney disease

Background: chronic kidney disease (ckd) is a major health problem throughout the world, and understanding the pathological condition of ckd has become increas- ingly important. the recent development of advanced metabolomic assay techniques now allows the human metabolic condition to be evaluated sensitively and compre- hensively. objectives: the aim of this study was to use metabolomic analysis to perform a prelimi- nary survey of metabolic changes occurring in patients with stage 1-2 ckd. patients and methods: serum and urine metabolomic profiles of 15 patients with stage 1-2 ckd were analyzed using our previously reported capillary electrophoresis time-of- flight mass spectrometry (ce-tofms) systems, and compared to 7 healthy volunteers. results: the ce-tofms systems in three different modes for cation, anion, and nucle- otide analyses detected multiple metabolites in serum and urine samples. in cation analysis mode, several increases in nonessential amino acids were identified in pa- tients with stage 1-2 ckd, similar to those reported for end-stage renal disease (esrd). free-radical scavengers carnosine and hypotaurine were decreased in the urine, whereas serum hypotaurine and taurine were increased, consistent with changes in renal and/or systemic oxidative stress. moreover, the cardiotoxin hypoxanthine was markedly increased in the serum, whereas serum and urine adenosine and urine gua- nine were decreased, suggesting changes in purine nucleotide metabolism which could affect cardiovascular prognosis. changes in other unidentified metabolites were also detected. conclusions: these results suggest that multiple changes in the metabolism are al- ready detectable in stage 1-2 ckd using metabolome analysis. further studies on these metabolic changes may result in new strategies to prevent cardiovascular events and progression to esrd in patients with ckd.