Evaluation of urinary 8-hydroxydeoxy-guanosine as a novel biomarker of macrovascular complications in type 2 diabetes

OBJECTIVE - To evaluate urinary 8-hydroxydeoxyguanosine (8-OHdG)as a market for the progression of diabetic macroangicipathic complications. RESEARCH DESIGN AND METHODS - The content of urinary 8-OHdG, common carotid intima-media thickness (IMT), the coronary heart disease (CHD) risk score, the severity of diabetic retinopathy, and urinary albumin excretion were examined in 96 patients with type 2 diabetes, including 32 patients who had been nominated for the Kumamoto Study [Shichiri M, et al. Diabete Care 23 (Suppl 2) B21-1329, 2000]. In addition, the patients from the Krumamoto Study were futher evaluated regarding the effect of intensive insulin therapy on urinary 8-OHdG, excretion. RESULTS - The urinary 8-OHdG:creatinine ratio (U8-OHdG) was 2.5-fold higher in patients with increased HbA(1c) than in those with normal HbA(1c) (P < 0.05). In addition, U8-OHdG was 2.3-fold higher in patients with increased IMT (P < 0.005). A simular result was observed between US-OHdG and CHD risk score (P < 0.01). U8-OHdG was significantly higher in patients With simple retinopathy (P < 0.05) and those With advanced retinopathy (P < 0.01) than in patients Without retinopathy. Similarly, U8-OHdG Was significantly higher in patients with albuminuria (P < 0.01). Furthermore, in the Kumamoto study, U8-OHdG was significantly lower in the Multiple insulin injection therapy group compared with the conventional insulin injection therapy group (P < 0 00). CONCLUSIONS - Hyperglycemia independently increases 8-OHdG in patients with type 2 diabetes. 8-OHdG is a useful biomarker of not only microvascular but also macrovascular complications in patients with type 2 diabetes.