Increased 8-hydroxy-2’-deoxyguanosine in leukocyte DNA from patients with type 2 diabetes and microangiopathy

OBJECTIVE To evaluate oxidative damage in leukocytes from patients with type 2 diabetes by examining 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. METHODS Patients with type 2 diabetes and healthy controls were assessed for demographic, clinical and biochemical characteristics. Levels of 8-OHdG in extracted leukocyte DNA were determined by enzyme linked immunosorbent assay. RESULTS Of 108 patients with type 2 diabetes (56 with microangiopathy, 52 without) and 65 healthy controls, leukocyte 8-OHdG levels were higher in patients with type 2 diabetes versus controls (median ± interquartile range [IQR], 3.19 ± 2.17 versus 0.38 ± 1.00 ng/ml), and higher in patients with type 2 diabetes and microangiopathy versus those without microangiopathy (median ± IQR, 3.34 ± 1.87 versus 2.71 ± 2.26 ng/ml). Patients with type 2 diabetes and microangiopathy had higher serum creatinine and urinary albumin levels versus those without microangiopathy. Leukocyte 8-OHdG levels, duration of type 2 diabetes, albuminuria, use of insulin and use of angiotensin-converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs) were independently associated with microangiopathy in patients with type 2 diabetes after adjustment for smoking. CONCLUSIONS Leukocyte oxidative DNA damage was high in patients with type 2 diabetes and microangiopathy. Presence of microangiopathy was associated with leukocyte 8-OHdG levels, duration of type 2 diabetes, albuminuria and use of ACE inhibitors/ARBs or insulin.