Urinary Proteome Profiling to Search for Biomarkers in Steroid-Resistant Nephrotic Syndrome

Long-term outcomes for patients with nephrotic syndrome (NS) correlate closely with the degree of steroid responsiveness. There are currently no diagnostic tests that accurately predict steroid responsiveness in NS. In children in particular, a prolonged course of daily, high-dose corticosteroid therapy is as much a diagnostic maneuver as it is a treatment. Urine proteomics has been emerging as a potentially rich source of noninvasive yet informative biomarkers of drug responsiveness in NS. In this review, we discuss some of the initial studies of the nephrotic urinary proteome as well as some ongoing and future challenges, including defining the normal urinary proteome, and extracting valuable urinary protein data from an abundance of urinary albumin.