Urinary 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'- deoxyguanosine (8-oxodGuo) are considered biomarkers of oxidative stress, and patients with nephrotic syndrome have been reported to have increased oxidative stress levels. In this study, we aimed to assess the value of 8-oxoGuo and 8-oxodGuo as novel biomarkers to evaluate the severity of nephrotic syndrome. In total, 107 patients with nephrotic syndrome and 116 healthy controls were recruited for this study. The concentrations of urinary 8-oxoGuo and 8-oxodGuo were measured using isotope-labeled liquid chromatography with tandem mass spectrometry. Urinary creatinine was used to regulate 8-oxoGuo and 8-oxodGuo concentrations. Urinary 8-oxoGuo and 8-oxoGuo/Cr levels in patients with nephrotic syndrome were significantly higher than those in healthy control participants. 8-oxoGuo/Cr showed a positive correlation with the 24 h urinary total protein (UTP) and UTP levels and negative correlations with serum total protein and albumin levels. After treatment, urinary 8-oxoGuo and 8-oxoGuo/Cr levels were significantly lower in the group with a low 24 h-UTP value (<3.5 g/d) than in the high value group. 8-oxoGuo can be used as a feasible and reliable biomarker for the assessment of nephrotic syndrome.HighlightsUrinary 8-oxoGuo level was significantly increased in patients with nephrotic syndrome.Urinary 8-oxoGuo level increased with an increase in plasma protein and a decrease in urine protein.Urinary 8-oxoGuo level decreased with nephrotic syndrome remission when urinary microalbumin showed no significant change.Urinary 8-oxoGuo level can be used as novel biomarkers of nephrotic syndrome.
Keywords: 8-oxoGuo; biomarker; nephrotic syndrome; oxidative stress.