Preliminary study on application of urine amino acids profiling for monitoring of renal tubular injury using GLC-MS.

Abstract

The early diagnosis of the nephrotoxic effect of xenobiotics and drugs is still an unsolved problem. Recent studies suggest a correlation between the nephrotoxic activity of xenobiotics and increased concentration of amino acids in urine. The presented study was focused on the application of GLC-MS method for amino acids profiling in human urine as a noninvasive method for monitoring of kidney condition and tubular injury level. The analytic method is based on the conversion of the amino acids present in the sample to tert-butyldimethylsilyl (TBDMS) derivatives and their analysis by gas-liquid chromatography-mass spectrometry (GLC-MS). The procedure of urine sample preparation for chromatographic analysis was optimized. The presence of 12 amino acids in most of the tested healthy human urine samples was detected. The significant differences in the levels of particular amino acids between patients with tubular injury and healthy controls were found, especially for lysine, valine, serine, alanine and leucine (on average 30.0, 7.5, 3.6, 2.9 and 0.5 fold respectively). We found that this approach based on GLC-MS detection can be used in nephrotoxicity studies for urine amino acids monitoring in exposure to xenobiotics and drugs.