title: How the duration period of erythropoietin treatment influences the oxidative status of hemodialysis patients.
abstract: BACKGROUND
  End-stage renal disease is a state of enhanced oxidative stress (OS) and hemodialysis (HD) and renal anemia further augment this disbalance. Anemia correction with erythropoietin (EPO) may improve oxidative status. However, there is no evidence of time dependent effects of EPO therapy on redox status of HD patients.
  
  
  OBJECTIVE
  The aim of this study was to evaluate whether the duration of EPO treatment may affect OS parameters in uremic patients.
  
  
  METHODS
  104 HD patients and 29 healthy volunteers were included. Patients were divided into 3 groups according to the duration of EPO treatment. Forth group consisted of HD patients without EPO treatment. Plasma and erythrocyte malondialdehyde (MDA, MDA(rbc)), reactive carbonyl groups (RCG), plasma sulfhydryl (-SH) groups and total antioxidative capacity (TAC) levels were evaluated.
  
  
  RESULTS
  HD patients both with and without EPO treatment, showed a significant increase in all oxidative parameters without significance between EPO treated and -untreated group. The decrease in MDA and MDA(rbc) levels coincided with the duration of EPO treatment. A negative correlation was observed between the duration of EPO treatment and serum MDA (r=-0.309, p=0.003). Increasing periods of EPO treatment were associated with decrease in RCG, without significance between EPO groups. Increase in TAC accompanied increasing durations of EPO treatment, with EPO treatment for more than 24 months causing the most striking changes (p<0.05). There were no significant differences in -SH levels between EPO subgroups.
  
  
  CONCLUSIONS
  Our results suggest that long term administration of EPO attenuated the lipid peroxidation process and restored the levels of antioxidants.
authors.affiliation: Clinic of Nephrology and Hemodialysis, Clinical Center, Nis, Serbia. d.iva@sezampro.rs
authors.forename: Zorica M
authors.initials: ZM
authors.lastname: Dimitrijevic
authors.forename: Tatjana P
authors.initials: TP
authors.lastname: Cvetkovic
authors.forename: Vidojko M
authors.initials: VM
authors.lastname: Djordjevic
authors.forename: Dusica D
authors.initials: DD
authors.lastname: Pavlovic
authors.forename: Nikola Z
authors.initials: NZ
authors.lastname: Stefanovic
authors.forename: Ivana R
authors.initials: IR
authors.lastname: Stojanovic
authors.forename: Goran J
authors.initials: GJ
authors.lastname: Paunovic
authors.forename: Radmila M
authors.initials: RM
authors.lastname: Velickovic-Radovanovic
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D000740:Anemia / Q000188:drug therapy*; D000975:Antioxidants / Q000378:metabolism*; D003430:Cross-Sectional Studies; D004334:Drug Administration Schedule; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D004921:Erythropoietin / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects*; D006435:Renal Dialysis / Q000009:adverse effects*; D013997:Time Factors; D014511:Uremia / Q000188:drug therapy
chemical_list: D000975:Antioxidants; D004921:Erythropoietin; D008315:Malondialdehyde
keywords: erythropoietin; hemodialysis; malondialdehyde; oxidative stress; total antioxidative capacity.