Activity of paraoxonase 1 (PON1) on HDL2 and HDL3 subclasses in renal disease

Introduction: Cardiovascular complications, as the main cause of mortality in renal patients, are followed with altered lipoproteins composition. Considering that paraoxonase-1 (PON1) is an anti-oxidative enzyme located mainly on HDL particles, the current study has aim to investigate whether failure of kidney function leads to changes in the distribution of PON1 activity between different HDL subclasses. Materials and methods: In 77 renal patients (21 chronic kidney disease (CKD) and 56 end stage renal disease (ESRD) patients on dialysis) and 20 healthy subjects PON1 activity on HDL2 and HDL3 subclasses was determined by zymogram method that combines gradient gel electrophoresis separation of HDL subclasses and measurement of PON1 activity in the same gel. Results: Serum paraoxonase (p < 0.01) and arylesterase activity (p < 0.001) of PON1 as well as its concentration (p < 0.01) were significantly lower in CKD and ESRD patients compared to controls. Relative proportion of HDL3 subclasses was higher in ESRD patients than in healthy participants, while HDL2 subclasses was significantly decreased in CKD (p < 0.05) and ESRD (p < 0.001) patients, as compared to controls. Furthermore, control subjects had higher PON1 activity on HDL2 (CKD and ESRD patients p < 0.001) and HDL3 (CKD p < 0.05; ESRD patients p < 0.001) subclasses in comparison with the both patients groups. Also, significant negative correlation was found between paraoxonase activity of PON1 in serum and creatinine concentration (rho = -0.373, p < 0.01). Conclusions: This study showed that altered HDL subclasses distribution, changed PON1 activities on different HDL subclasses as well as diminished anti-oxidative protection could be important factors in atherosclerosis development in CKD and ESRD patients.