Assessment of the relationship between serum paraoxonase activity and epicardial adipose tissue in hemodialysis patients

Paraoxonase-1 (PON-1) is a high-density lipoprotein-associated (HDL) enzyme, which has been shown to reduce susceptibility to low-density lipoprotein (LDL) peroxidation. Epicardial adipose tissue (EAT) is a marker of atherosclerosis. The aim of this study was to determine the relationship between PON-1 activity and EAT in hemodialysis (HD) patients. This is a cross-sectional study conducted on 72 (43 males) HD patients with end-stage renal disease. Serum levels for lipid profiles, C-reactive protein, calcium, phosphate, and parathyroid hormone were measured. PON-1 activity was also measured and compared to the rate of enzymatic hydrolysis of paraoxon to p-nitrophenol. Echocardiography was used to measure EAT thickness (EATT). The correlation between PON-1 and EATT was assessed, while independent predictors of EATT in HD patients were similarly assessed using multivariate regression analysis. There was a significant low mean value of PON-1 activity in HD patients compared with the control group (82.1 +/- 31.6 vs. 164.3 +/- 61.5 U/l, p = 0.0001) and significant high mean value of EATT in HD patients, compared with controls (6.2 +/- 1.7 vs. 3.9 +/- 1.1 mm, p = 0.0001). In addition, there was a significant negative correlation between PON-1 activity and EATT (r = -0.484, p = 0.0001) and a significant positive correlation between PON-1 activity and HDL-C (r = 0.417, p = 0.0003). PON-1, total cholesterol, triglycerides, LDL, HDL, age, and body mass index were found to be independent predictors of EATT. Our study demonstrated that PON-1 activity was significantly lower in HD patients compared with healthy controls and that PON-1 activity was inversely correlated with EATT in this population.