Oxidative stress markers in type 2 diabetes patients with diabetic nephropathy.

BACKGROUND: Epidemiological studies show that 5-40 % of type 2 diabetes (T2DM) patients have diabetic nephropathy, and oxidative stress is one of several underlying mechanisms. We investigated associations between oxidative stress markers and severity of diabetic nephropathy.

METHODS: Fifty-nine T2DM patients from the endocrinology outpatient department were included, and their levels of oxidative stress markers were measured. Three groups were determined by their urine albumin-to-creatinine ratio (UACR): group A (UACR < 30 mg/g, n = 22); group B (30 ≤ UACR < 300 mg/g, n = 22); and group C (UACR ≥ 300 mg/g, n = 15).

RESULTS: Vitamin C levels correlated negatively and moderately with serum creatinine (γ = -0.459, p < 0.001), urine albumin (γ s = -0.458, p = 0.001) and UACR (γ s = -0.408, p = 0.001), but only weakly with hydroxy-2-deoxyguanosine (8-OHdG) and estimated glomerular filtration rate (eGFR). Vitamin C levels decreased as 8-OHdG, serum creatinine, albumin and UACR increased. T2DM patients with more severe diabetic nephropathy had lower vitamin C levels.

CONCLUSION: Our results identified several oxidative stress markers that may be clinically important in diabetic nephropathy. Studies with larger sample sizes should be undertaken to confirm these findings.