Do trace elements modify the activity of erythrocyte sodium-proton exchanger in hemodialyzed patients?
The kinetics (Vmax and Km) of the erythrocyte Na+-H+ exchanger was studied in a group of 21 patients undergoing regular hemodialysis (HD) and in 21 control subjects. The activity of antioxidative enzymes--superoxide dismutase and glutathione peroxidase--as well as the concentrations of their cofactors--zinc, copper, and selenium--in plasma and in erythrocytes were determined. The thiobarbituric acid-reactive substances (TBARS) concentration served as an indicator of oxidative stress intensity in plasma and erythrocytes. It was found that in the control group the concentration of copper in erythrocytes was positively correlated with Km and Vmax. When the concentration of copper increased, the shape of the kinetic curve changed from sigmoidal to hyperbolic. In the control group, the concentration of zinc in erythrocytes also correlated with Km. However, the results obtained for the group of hemodialyzed patients were the opposite: when the erythrocyte concentration of copper increased, a Km decline was observed and the shape of the curve changed from hyperbolic to sigmoidal. In the group of hemodialyzed patients, we also found a positive correlation between Km and the concentration of selenium in erythrocytes, and a negative correlation between Km and erythrocyte TBARS.
Bober
Joanna
J
Department of Biochemistry and Chemistry, Transplantology and Internal Medicine, Pomeranian Medical University, Szczecin, Poland.
Kwiatkowska
Ewa
E
Ciechanowski
Kazimierz
K
Kedzierska
Karolina
K
Dołegowska
Barbara
B
Olszewska
Maria
M
Kucharska
Elzbieta
E
Gołembiewska
Edyta
E
Chlubek
Dariusz
D
D003300:Copper / Q000097:blood; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy*; D007700:Kinetics; D008315:Malondialdehyde / Q000097:blood; D018384:Oxidative Stress / Q000502:physiology*; D006435:Renal Dialysis / Q000009:adverse effects; D012643:Selenium / Q000097:blood; D017923:Sodium-Hydrogen Exchangers / Q000097:blood*; D013482:Superoxide Dismutase / Q000097:blood; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014131:Trace Elements / Q000097:blood*; D015032:Zinc / Q000097:blood
D017923:Sodium-Hydrogen Exchangers; D017392:Thiobarbituric Acid Reactive Substances; D014131:Trace Elements; D008315:Malondialdehyde; D003300:Copper; D013482:Superoxide Dismutase; D012643:Selenium; D015032:Zinc