Paraoxonase activity in healthy, diabetic, and hemodialysis patients.

Objectives: Paraoxonase 1 (PON1) is mainly complexed to HDL and is responsible, at least in part, for their antioxidant properties. The aims of our study were to determine the phenotype distribution and enzymatic activities of PON1 and the oxidative stress status of healthy subjects and diabetic and hemodialysis patients.

Design And Methods: PON1 paraoxonase and arylesterase activities and oxidative stress markers [malondialdehyde (MDA) and vitamin E levels] were measured in 300 individuals as a function of health status.

Results: The prevalence of the PON1 phenotypes in the study population was 74.51%, 18.15% and 7.34% for QQ, QR and RR, respectively. The phenotype distribution did not change significantly as a function of health status (healthy, diabetes, hemodialysis). However, the hemodialysis patients had lower PON1 paraoxonase and arylesterase activities than the diabetic patients and healthy subjects, while there were no significant differences between the diabetic patients and the healthy subjects. Oxidative stress markers (MDA levels and vitamin E/cholesterol ratio) were significantly higher in the diabetic and hemodialysis patients than in the healthy subjects.

Conclusions: The lower plasma PON1 enzymatic activities in the hemodialysis patients was not associated with a difference in the phenotype distribution of PON1. Oxidative stress conditions were significantly higher in these patients, which may increase the risk of atherosclerosis in this population.