Serum levels of advanced glycation end products are increased in patients with type 2 diabetes and coronary heart disease

OBJECTIVE - To investigate whether serum levels of advanced glycation end products (AGEs) and the glycoxidation product N-epsilon-(carboxymethyl)lysine (CML) are increased in patients with type 2 diabetes compared with nondiabetic control subjects and whether levels of AGEs and/or CML differ in patients with type 2 diabetes with or without coronary heart disease (CHD). RESEARCH DESIGN AND METHODS - Serum levels of AGEs and CML were measured with an immunoassay in 32 men and 21 women aged 59.3 +/- 6.2 years (means +/- SD) with type 2 diabetes for 7.3 +/- 3.1 years and in 17 men and 17 women aged 56.2 +/- 4.2 years without diabetes. Of the patients with diabetes, 18 had CHD. RESULTS - The serum levels of AGEs and CML were significantly increased in patients with type 2 diabetes compared with nondiabetic control subjects (median [5th-95th percentile]: AGEs 7.4 [4.4-10.9] vs. 4.2 [1.6-6.4] U/ml, P < 0.0001; CML 15.6 [5.6-29.9] vs. 8.6 [4.4-25.9] U/ml, P < 0.0001). The median level of AGEs but not CML was significantly increased in patients with type 2 diabetes and CHD compared with patients without CHD (8.1 [6.4-10.9] vs. 7.1 [3.5-9.8] U/ml, P = 0.03). There were significant positive correlations between serum levels of AGEs and CML in both patients and control subjects. CONCLUSIONS - Levels of AGEs and CML were significantly increased in patients with type 2 diabetes compared with nondiabetic control subjects, and levels of AGEs but not CML were significantly higher in patients with type 2 diabetes and CHD than in patients without diabetes. These results may indicate a role for non-CML AGEs in the development of macrovascular disease in patients with type 2 diabetes.