CKD Urine Metabolomics: Modern Concepts and Approaches

Abstract

One of the primary challenges regarding chronic kidney disease (CKD) diagnosis is the absence of reliable methods to detect early-stage kidney damage. A metabolomic approach is expected to broaden the current diagnostic modalities by enabling timely detection and making the prognosis more accurate. Analysis performed on urine has several advantages, such as the ease of collection using noninvasive methods and its lower protein and lipid content compared with other bodily fluids. This review highlights current trends in applied analytical methods, major discoveries concerning pathways, and investigated populations in the context of urine metabolomic research for CKD over the past five years. Also, we are presenting approaches, instrument upgrades, and sample preparation modifications that have improved the analytical parameters of methods. The onset of CKD leads to alterations in metabolism that are apparent in the molecular composition of urine. Recent works highlight the prevalence of alterations in the metabolic pathways related to the tricarboxylic acid cycle and amino acids. Including diverse patient cohorts, using numerous analytical techniques with modifications and the appropriate annotation and explanation of the discovered biomarkers will help develop effective diagnostic models for different subtypes of renal injury with clinical applications.

Keywords: biomarkers; chronic kidney disease; mass spectrometry; metabolomic; nuclear magnetic resonance.

Figure 1

The “vicious circle” of CKD. Pathogenetic mechanisms underlying chronic kidney disease inevitably form a circle, leading to major organ damage. The direction of the red arrows shows the up- or down-regulation of processes or the increase/decrease in the number of cells or other functional units.