Kidney-specific metabolomic profiling in machine perfusate.

Given their accessibility and relevance to established clinical workflows, blood and urine have been the major focus of investigation in metabolomics studies of human kidney disease. In this issue, Liu et al. describe the application of metabolomics to perfusate from donor kidneys subjected to hypothermic machine perfusion. In addition to providing an elegant model for investigating kidney metabolism, this study highlights the limitations of allograft quality assessment and identifies metabolites of interest in kidney ischemia.