RNA oxidation and albuminuria in type 1 diabetes patients

We examined the relationship between urinary excretion of the RNA oxidation marker 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and kidney injury comparing type 1 diabetes patients with different levels of albuminuria (normoalbuminuria: N=58, microalbuminuria: N = 46, macroalbuminuria: N =46) and a nondiabetic control group (N=57). Urinary 8-oxoGuo was measured in spot urine samples using ultraperformance liquid chromatography and tandem mass spectrometry. Urinary 8-oxoGuo was significantly higher in the patients [2.85 (2.45-3.33) vs. 2.49 (2.12-2.96)nmol/mmol creatinine, P=0.01]. However, after adjustment for possible confounders of oxidative stress, the differences reduced slightly and became statistically nonsignificant (P = 0.07). There were no significant differences in the level of 8-oxoGuo between the three groups of patients (P = 0.53) and there were no significant associations between 8-oxoGuo and estimated glomerular filtration rate or albumin-creatinine ratio. In conclusion, urinary excretion of the RNA oxidation marker 8-oxoGuo does not differ between type 1 diabetes patients with different levels of albuminuria.