Relationship of PON1 activity and hsCRP concentration with disease status in patients with type 2 diabetes mellitus with and without retinopathy

The purpose of this study was to determine paraoxonase-I activity (PON 1), lipid profile and hsCRP in type 2 diabetic patients with and without retinopathy who had the same duration of the disease (10 years), to determine the correlations among these parameters and to compare these values with those measured in normal control subjects. Fifty four subjects (mean age 58 +/- 7 years, men / women 25/29) with type 2 diabetes (T2DM) with proliferative diabetic retinopathy (PDR) (N = 25) and without retinopathy (nonDR) (N = 29) were included in the study. Twenty four healthy subjects were selected as control group (61 +/- 6 years, men / women 10/14). Paraoxonase and arylesterase activities were measured spectrophotometrically. The DM + PDR group had lower paraoxonase activity (199 +/- 39 vs. 258 +/- 60 U/L, P < 0.05) and higher hsCRP (5.8 +/- 4.9 vs. 3.2 +/- 1.1 mg/L, P < 0.05) than the healthy control group. In patients with DM, paraoxonase activity was positively associated with HDL cholesterol and negatively associated with serum glucose, total cholesterol, and LDL cholesterol. Although hsCRP was elevated and paraoxonase was decreased in type 2 diabetic patients, a link between oxidation and inflammation and the development of diabetic retinopathy remains unexplored.