Paraoxonase enzyme activity is enhanced by zinc supplementation in hemodialysis patients

Patients on maintenance hemodialysis (HD) face an increased risk of atherosclerosis, a crucial problem and the leading cause of cardiovascular morbidity and mortality. This study was designed to evaluate the effects of zinc supplementation on paraoxonase (PON) enzyme activity in patients on HD.

This double-blind randomized controlled trial was conducted from June 2005 to June 2007. Sixty HD patients were enrolled and divided into two groups: treatment (case) and control. The treatment and control groups were treated with 100 mg/day zinc or placebo, respectively, for 2 months. Serum zinc concentration was measured by atomic absorption spectrophotometry. PON activity was evaluated by spectrophotometric method. Lipid profile was determined using commercial kits, and apolipoprotein AI (Apo-AI) and B (Apo-B) levels were measured by commercial immunoturbidimetric kits.

In the case group, there was no significant change in the serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), and Apo-B levels, while the serum levels of high-density lipoprotein (HDL), Apo-AI, and PON activity were significantly increased (p = 0.02). In the control group, although significant increases were observed in the serum levels of TC, TG, and Apo-B (p = 0.009, 0.019, and 0.001, respectively), the serum PON activity was significantly decreased (p = 0.025) and the serum levels of HDL, LDL, and Apo-AI were not changed. At the end of intervention period, the serum level of Apo-AI and PON activity were significantly higher in the case group.

Zinc supplementation increased both the activity of PON and the serum level of Apo-AI in the HD patients.