title: Oxidized low-density lipoprotein (oxLDL) plasma levels and oxLDL to LDL ratio - are they real oxidative stress markers in dialyzed patients?
abstract: OBJECTIVE
  Dyslipidemia and oxidative stress are commonly present in patients during maintenance dialysis treatment. However, the significance of oxidized LDL (oxLDL) as a marker of oxidative stress in uremia is still unresolved. The aim of this study was to establish the role of oxLDL and oxLDL/LDL ratio as markers of lipoprotein abnormalities and oxidative stress in the dialyzed patients.
  
  
  METHODS
  Plasma oxLDL level was measured by ELISA, and oxLDL/LDL ratio was calculated in 106 dialyzed patients and 20 controls. The linkages between oxLDL, oxLDL/LDL ratio and lipid profile and oxidative stress markers malondialdehyde (MDA) and Cu/Zn superoxide dismutase (Cu/Zn SOD) levels were also analyzed.
  
  
  RESULTS
  OxLDL levels and oxLDL/LDL ratio were similar in hemodialyzed patients and controls, whereas these parameters were lower in peritoneally dialyzed patients when compared to healthy individuals. In contrast, both MDA and Cu/Zn SOD levels were significantly higher in uremics than in controls. oxLDL and oxLDL/LDL ratio positively correlated with lipid profile (except of HDL), whereas there were no positive associations between these parameters and both MDA and Cu/Zn SOD. Multiple regression analysis confirmed that increased oxLDL/HDL and TC/HDL ratios and total cholesterol levels are the parameters which independently predicted oxLDL in dialyzed patients. In the case of oxLDL/LDL ratio, the independent variables were oxLDL/HDL ratio, total cholesterol and HDL levels.
  
  
  CONCLUSIONS
  oxLDL levels and oxLDL/LDL ratio seem to be the markers of lipoprotein abnormalities rather than the markers of oxidative stress in the population of dialyzed patients.
authors.affiliation: Department of Monitored Pharmacotherapy, Medical University, Bialystok, Poland.
authors.forename: Krystyna
authors.initials: K
authors.lastname: Pawlak
authors.forename: Michal
authors.initials: M
authors.lastname: Mysliwiec
authors.forename: Dariusz
authors.initials: D
authors.lastname: Pawlak
mesh_terms: D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D003430:Cross-Sectional Studies; D003627:Data Interpretation, Statistical; D050171:Dyslipidemias / Q000097:blood* / Q000209:etiology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D012044:Regression Analysis; D006435:Renal Dialysis / Q000009:adverse effects / Q000379:methods; D013482:Superoxide Dismutase / Q000097:blood; D014511:Uremia / Q000097:blood* / Q000209:etiology
chemical_list: D015415:Biomarkers; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D008315:Malondialdehyde; D002097:C-Reactive Protein; D013482:Superoxide Dismutase