Urine Protein Analysis May Help Spot Diabetic Nephropathy

Dr. Loreto Gesualdo and colleagues used a noninvasive method that reliably differentiated between diabetic and non-diabetic nephropathy and chronic kidney disease (CKD).

Using urine protein patterns generated via surface enhanced laser desorption/ionization time-of-flight mass spectrometry, the researchers from the University of Foggia, Italy, sought to distinguish biopsy-proven diabetic nephropathy from other forms of CKD in non-diabetic and diabetic patients.

Accordingly, the team examined urine proteins from 20 healthy subjects and 20 normoalbuminuric and 18 microalbuminuric diabetic patients. Also included were 65 patients with diabetic nephropathy, 10 diabetics with CKD and 57 non-diabetic patients with CKD.

Application of the approach and subsequent analysis allowed the generation of a robust multi-parametric panel of mass peaks. When applied to a blinded testing set, the approach correctly identified 75% of normoalbuminuric and 87.5% of microalbuminuric diabetics. It also identified 87.5% of cases of diabetic nephropathy.

Two proteins, ubiquitin and beta2-microglobulin, were identified and validated as being the best predictors.

Dr. Gesualdo stated that, "These findings, if confirmed in larger cohorts of diabetic patients … encourage the use of supervised learning approaches for the analysis of urine proteomic profiles" to achieve a non-invasive differential diagnosis of renal lesions in diabetics.

"The appraisal of their possible predictive power," he concluded, "demands longitudinal studies."

Diabetes Care. Posted online July 29, 2010. Abstract