title: Biomarkers of oxidative damage and antioxidant enzyme activities in pre-dialysis Balkan endemic nephropathy patients.
abstract: OBJECTIVE
  To obtain more insight into molecular mechanisms underlying oxidative stress in Balkan endemic nephropathy (BEN), biomarkers of oxidative stress and antioxidant enzyme activities were studied in 38 pre-dialysis BEN patients, 21 healthy BEN family members and 36 healthy subjects from non-endemic areas.
  
  
  METHODS
  Protein thiol groups (P-SH), antioxidant enzyme activities [superoxide dismutase (SOD) and glutathione peroxidase (GPX)], were determined in plasma spectrophotometrically, while malondialdehyde adducts (MDA) by enzyme immunoassay.
  
  
  RESULTS
  BEN patients had significantly lower plasma GPX activity in comparison with values for both control groups (p = 0.016), gradually decreasing with kidney function impairment estimated by glomerular filtration rate (r = 0.53, p = 0.002). GPX activity was inversely correlated with serum urea (r = -0.627, p < 0.001), creatinine (r = -0.53, p < 0.05), urinary excretion of protein and α1-microglobulin (r = -0.44, p = 0.012; r = -0.50, p < 0.007). Significant upregulation of SOD activity was observed in healthy BEN family members (p < 0.05). While the concentration of MDA adducts was similar in all three groups, BEN patients and healthy BEN family members exhibited increased protein damage, based on fewer P-SH groups in comparison with subjects from non-BEN areas (p = 0.085; p = 0.014, respectively).
  
  
  CONCLUSIONS
  Based on our results on increased oxidative protein damage in both pre-dialysis BEN patients and healthy BEN family members, it can be speculated that individuals from BEN areas, in general, are chronically exposed to some prooxidant environmental compounds. Moreover, decrease in plasma GPX activity, as a consequence of impaired kidney function, could further affect oxidative status in BEN patients.
authors.affiliation: University Hospital Foča, Foča, Bosnia and Herzegovina.
authors.forename: Dragana
authors.initials: D
authors.lastname: Pavlović
authors.affiliation: Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia.
authors.forename: Ana
authors.initials: A
authors.lastname: Savić-Radojević
authors.affiliation: Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia.
authors.forename: Marija
authors.initials: M
authors.lastname: Plješa-Ercegovac
authors.affiliation: Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia.
authors.forename: Tanja
authors.initials: T
authors.lastname: Radić
authors.affiliation: University Hospital Foča, Foča, Bosnia and Herzegovina.
authors.forename: Slavica
authors.initials: S
authors.lastname: Ristić
authors.affiliation: Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Ćorić
authors.affiliation: Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia.
authors.forename: Marija
authors.initials: M
authors.lastname: Matić
authors.affiliation: Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Simić
authors.affiliation: Faculty of Medicine, University of Belgrade, Pere Velimirovića 54/15, Belgrade, 11 000, Serbia. ljubicadjukanovic@yahoo.com.
authors.forename: Ljubica
authors.initials: L
authors.lastname: Djukanović
mesh_terms: D000328:Adult; D001449:Balkan Nephropathy / Q000201:enzymology* / Q000503:physiopathology / Q000628:therapy; D015415:Biomarkers / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D005979:Glutathione Peroxidase / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D011379:Prognosis; D006435:Renal Dialysis; D013482:Superoxide Dismutase / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase
keywords: Antioxidant enzyme activities; Balkan endemic nephropathy; Oxidative stress