Lipids, apolipoproteins, lipid oxidation and paraoxonase enzyme activity in diabetic and non-diabetic end stage renal disease patients

Paraoxonase (an HDL-associated enzyme) is believed to protect lipoproteins against peroxidation. Patients with end stage renal failure on hemodialysis are exposed to oxidative stress. In this study we investigated the status of paraoxonase activity, TAC and oxidized LDL in a population of diabetic and non-diabetic ESRD patients. The study population consisted of 46 patients with diabetes and 46 non diabetics and 46 control participants. Patients were selected from hemodialysis centers of Shaheed Beheshti University of Medical Sciences. Individuals with thyroid dysfunction, Cerebrovascular accident, recent coronary event, recent hospitalization or under treatment with lipid-lowering agents were excluded. A fasting predialysis sample was obtained. Paraoxonase activity was measured by spectrophotometer, measuring P-nitrophenol paraoxon after adding paraoxon to the sera and TAC by adding 20µL serum to PBS (80µmol/L, PH=7.4) and 6.1 µmol/L metmyoglobin and ABTS (as a chromogen and substrate) and hydrogen peroxide as a substrate. The decrease in blue-green color was measured by Elisa reader. 46 diabetic patients, 26 men and 20 women, aged 61.8±10 and 46 non diabetic ESRD patients, 25 men and 21 women, aged 61.5±9.9, and 46 healthy controls, 24 men and 22 women, aged 60.8±10.0 were studied. Significant reduction in serum paraoxonase activity in non diabetic ESRD and diabetic patients compared with control group was present (47.2±32.2 VS 9.5±48.6 VS 86.4±62.5 IU/mL, respectively). While these groups showed no significant change in oxidized LDL and TAC. Paraoxonase activity was significantly lower in non diabetic ESRD patients than diabetics. It has been shown that there is enhanced oxidative stress in patients with diabetes mellitus and chronic renal failure. Reduction in paraoxonase activity may have a role in this process.