Abstract:
Kidney stone disease or urolithiasis is a common urologic disease in elderly worldwide. It is well-recognized that familial members of urolithiasis patients have higher risk for stone development than normal population. Our previous study showed that the urolithiasis descendants had higher urinary lithogenic (calcium), lower anti-lithogenic (citrate) and elevated proteinuria level than normal population. These abnormalities were also observed in urolithiasis patients. The present study aimed to analyze the type of urinary proteins which were increased in urolithiasis descendants and identify a biomarker protein for the risk of stone development in urolithiasis family. Urine samples from 30 urolithiasis descendants (G1) and 30 descendant controls (G2) were used. The samples were separated by one-dimensional polyacrylamide gel electrophoresis (1D-PAGE) and the protiens were identified by nanoscale liquid chromatography coupled to tandem mass spectrometry (nanoLC-MS/MS). Total 349 proteins were identified in the urine of urolithiasis and control descendants. Among these, 18 proteins were significantly higher (all 3-pair comparison between) urolithiasis than control descendants, including 17 proteins plasma-derived and only one protein that is plasma-derived and kidney-derived. We used the urinary albumin as a candidate protein for the increased risk of stone formation in urolithiasis family. G1 had higher albumin levels than G2 (5.92±10.48 mg/day and 0.41±0.78 mg/day respectively, p-value=0.006*). The levels of the urinary albumin in urolithiasis patients was also higher than normal (16.85 ±33.41 mg/day and 0.26±0.71 mg/day respectively, p value < 0.001). However, we could not identified the correlation between supersaturation levels, indicated by Ogawas index, and the urinary albumin excretion in all groups.