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 (ρ=-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.

Dyslipidemia and oxidative stress in sarcoidosis patients.

OBJECTIVES: Sarcoidosis is an inflammatory disease characterised by enhanced production of reactive oxygen species and alterations in the circulating lipid profile. Both attributes are thought to play a role in its pathogenesis. However, current knowledge regarding the significance of blood oxidative stress/anti-oxidant defence as well as alterations in lipid status parameters in sarcoidosis is scarce. The aim of our study was to assess these parameters and their inter-relationships, as well as their potential for patient-control discrimination. DESIGN AND METHODS: Oxidative stress status and anti-oxidant defence parameters were determined in serum and erythrocytes and lipid status parameters were assessed in the serum of 213 treated sarcoidosis patients and 90 controls. RESULTS: Malondialdehyde, superoxide anion, total oxidant status, prooxidant-antioxidant balance and triglycerides were significantly higher whereas total anti-oxidant status, superoxide dismutase activity and HDL-cholesterol were significantly lower in sarcoidosis patients compared with controls. Total sulfhydryl group content was higher in patients compared with controls. Serum and erythrocyte malondialdehyde exhibited the strongest ability to predict disease presence. Elevated oxidative stress was characterised by higher clinical accuracy compared with lipid status abnormality. Some oxidative stress and lipid status markers were significantly associated in sarcoidosis. CONCLUSIONS: Sarcoidosis is characterised by increased oxidative stress, diminished overall anti-oxidative protection and alterations in the circulating lipid profile. Both oxidative stress and lipid status parameters demonstrated the potential to discriminate sarcoidosis from controls which was particularly evident from the point of view of oxidative stress status parameters. Association between these parameters may indicate an increased risk for atherosclerosis development.