Two-dimensional electrophoresis of urine specimens from patients with renal disease.

In an effort to develop non-invasive markers capable of characterizing renal disease with greater sensitivity and specificity than those currently available, urinary proteins were studied by high-resolution two-dimensional electrophoresis in order to catalog those proteins which appeared to be most affected by a variety of renal diseases. Urine specimens were prepared by high-pressure liquid chromatography and subjected to two-dimensional gel electrophoresis. Proteins were visualized with silver stain. Gels from 17 patients were analyzed in detail and compared to standard maps of human urinary proteins and plasma. The two-dimensional gels displayed approximately 100 times the number of proteins demonstrated by high resolution agarose electrophoresis. We have identified 34 proteins whose urinary concentrations were most affected by renal disease. Twenty seven were of plasma origin, based upon comigration with plasma samples (17 of unknown identity and function). Seven proteins were observed in normal urine but not present in plasma. These proteins, which may represent kidney tissue proteins, were not apparent in the urine of patients with proteinuria, most likely due to dilutional effects.