Serum paraoxonase activity and its relationship to the atherogenic mechanism in chronic renal failure patients

Paraoxonase [PON] is an antioxidant high-density lipoprotein [HDL] linked enzyme; it is an esterase that hydrolyzes organophosphate compounds. HDL increases PON activity, while phospholipids and apo A-1 are necessary for its optimal activity and enzyme stability. This work is aimed to study the value of measurement of PON activity in chronic renal failure [CRF] patients hoping to find suitable therapeutic measures to prevent the occurrence of early atherosclerosis in these patients. This study included 50 subjects divided into 3 groups: Group A: 20 CRF patients received conservative treatment without dialysis. Group B: 20 CRF patients on regular haemodialysis for at least 3 months. Group C: 10 healthy volunteers served as controls. Serum total cholesterol, triglyceride, HDLc, apolipoprotein A-1, urea and creatinine were evaluated. The results of this study showed a highly significant decrease in the level of basal PON activity, salt- stimulated PON activity, arylesterase activity and Apo-A 1 in uremic patients [dialyzed and non-dialyzed] when compared with the control group [P0.05] . AA homozygous showed low activity phenotype, AB heterozygous intermediate activity phenotype, while BB homozygous showed high activity phenotype. In conclusion, the serum paraoxonase activity is decreased in CRF and in end stage renal diseases, with subsequent decrease of its antiatherogenic properties and this may provide a potential explanation for accelerated atherosclerosis in end stage renal disease