title: Increased hydrogen peroxide in the exhaled breath of uraemic patients unaffected by haemodialysis.
abstract: BACKGROUND
  Uraemia is accompanied by conditions favouring the rise of H2O2 activity in body fluids. This results from the increased release of H2O2 by polymorphonuclear leukocytes and decreased plasma glutathione peroxidase activity. The purpose of this study was to determine if patients on chronic haemodialysis (HD) exhale more H2O2 than healthy individuals, and if dialysis affects breath H2O2 content.
  
  
  METHODS
  We studied 29 chronic HD patients (mean age 49 +/- 11 years) and 40 healthy persons (mean age 44 +/- 9 years). H2O2, which is volatile, was measured fluorimetrically with the homovanillic acid method in the exhaled breath condensate (EBC) of the study cohort. EBC was collected immediately before and after the HD session and also at 20 and 60 min of HD treatment (n = 14) and once in controls. Peak expiratory flow (PEF), white blood cell (WBC) count, PaO(2) and circulatory cyclic guanosine monophosphate (cGMP), Il-6 and Il-8 concentrations were measured concomitantly. Finally, H2O2 diffusion through the dialyser cuprophane membrane was determined in an in vitro experiment.
  
  
  RESULTS
  At baseline, EBC H2O2 concentration was 22 times higher in HD patients than in controls (2.92 +/- 4.64 vs 0.16 +/- 0.13 microM, P < 0.001). Although the maximum decrease in PEF (431 +/- 52 vs 398 +/- 56 l/min, P < 0.01) and WBC count (6.72 +/- 1.02 vs 3.82 +/- 1.51 x 10(3)/ microl, P < 0.01) occurred at 20 min after the start of HD, no significant changes in breath H2O2 levels were noted throughout the session. Plasma IL-6 and IL-8 levels remained unchanged whereas cGMP rose 1.3 times at 60 min (P < 0.01). In vitro, H2O2 rapidly diffused through the cuprophane membrane.
  
  
  CONCLUSIONS
  Chronic HD patients exhale more H2O2 than healthy subjects. Although no change of breath H2O2 concentration was observed during HD, as H2O2 easily diffuses through the dialyser membrane, it is not possible to rule out that HD stimulates H2O2 generation.
authors.affiliation: Department of Internal Medicine and Dialysotherapy Medical University of Lodz, Mazowiecka Str. 6/8, 92-215 Lodz, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Rysz
authors.forename: Marek
authors.initials: M
authors.lastname: Kasielski
authors.forename: Joanna
authors.initials: J
authors.lastname: Apanasiewicz
authors.forename: Maciej
authors.initials: M
authors.lastname: Król
authors.forename: Andrzej
authors.initials: A
authors.lastname: Woźnicki
authors.forename: Marek
authors.initials: M
authors.lastname: Luciak
authors.forename: Dariusz
authors.initials: D
authors.lastname: Nowak
mesh_terms: D000328:Adult; D001944:Breath Tests; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis*; D007676:Kidney Failure, Chronic / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D014511:Uremia / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy
chemical_list: D006861:Hydrogen Peroxide