Alterations in plasma metabolome and correlation with urinary metabolome in cardiac surgery-associated acute kidney injury using ultra high-performance liquid chromatography-high resolution mass spectrometry

Cardiac surgery-associated acute kidney injury (CSA-AKI) may be related to an increase in mortality in patients in the intensive care unit; therefore, developing potential candidate molecule is particularly important for disease prediction and early diagnosis. This exploratory study investigated the alteration of the plasma metabolome profiles and possible links with the urinary metabolome in six patients with CSA-AKI at different time points, which could screen out the differential plasma metabolites for statistical analysis and altered metabolic pathways. After performing receiver operating characteristic analysis to obtain potential candidate molecules, the differential plasma metabolites with Level 1 were used for correlation analysis with the urinary metabolome. The plasma metabolome of the AKI group could be clearly separated from that of the uninjured kidney or recovered groups, but the plasma samples from recovered and uninjured groups could not be distinguished using statistical analysis. Compared with the uninjured kidney group, significant changes in the plasma metabolome were observed in such patients with CSA-AKI, especially regarding amino acid metabolism, spermidine and spermine biosynthesis, and sulfate/sulfite metabolism. The potential candidate molecules in the plasma metabolome, such as carnitines, exhibited a significantly positive correlation, while carnitines and organic acids in the plasma were involved in the correlation with the urinary metabolome. Plasma metabolic disorders were observed when CSA-AKI occurred, and the systemic status of recovered patients returned to normal after treatment. This exploratory investigation suggests potential candidate molecules in plasma and possible links to the urinary metabolome in CSA-AKI.