Proteomic approaches in kidney disease biomarker discovery

Biomarkers have the potential to greatly facilitate diagnosis and treatment of patients with various forms of kidney disease. State-of-the-art mass spectrometry-based methods possess the capability, on a proteome scale and in an unbiased manner, to detect alterations in protein abundances and/or posttranslational modifications in plasma, urine, or tissue. Such approaches can provide a large, unbiased database to facilitate identification of potential biomarkers. In the diagnosis of kidney diseases, urine is usually a more favorable specimen than plasma and kidney tissue due to its noninvasive collection and simplicity of processing. However, whether analysis of proteins in urine faithfully reflects their changes in the kidney tissue remains unclear. The use of proteomics to analyze kidney tissue samples collected during late-stage kidney diseases has also recently gathered pace. The goal of this minireview is to provide an overview of the proteomic technologies currently applied to studies of kidney and their limitations, present existing kidney and urine proteome databases, and highlight a few applications of such approaches in kidney disease biomarker discovery.