Serum paraoxonase enzyme activity and oxidative stress in obese subjects

Obesity is an important risk factor for atherosclerotic cardiovascular disease. Paraoxonase-1 (PON1) may play a significant role in the prevention of obesity-related accelerated atherosclerosis by hydrolyzing lipid peroxides in oxidized low-density lipoproteins.

The aim of this study was to evaluate PON1 and arylesterase enzyme activities and lipid hydroperoxide (LOOH) levels, and to investigate whether there is increased susceptibility to atherogenesis in obese subjects, which might be reflected by increased oxidative stress and decreased PON1 activity. We also aimed to investigate the association between PON1 activity and body mass index (BMI) in this patient group.

The study involved 25 obese subjects and 23 controls. Serum PON1 and arylesterase activity was measured spectrophotometrically. LOOH levels were measured by the FOX-2 assay.

Serum basal/salt-stimulated PON1 and arylesterase activities were significantly lower in obese subjects than in controls (P <0.001 for both enzymes), while LOOH levels were significantly higher (P <0.001). BMI was significantly correlated with PON1, arylesterase and LOOH levels (P <0.001, r = -0.720; P <0.001, r = -0.634; P <0.001, r = 0.491; respectively). Serum high-density lipoprotein (HDL) levels were positively correlated with PON1 activity (r = 0.347, P <0.05).

Our results indicate that obese subjects have increased oxidative stress and decreased PON1 activity, which might contribute to accelerated atherosclerosis. A decrease in PON1 activity seems positively correlated with BMI and inversely correlated with HDL levels.