Abstract
Objective
To investigate the overall susceptibility of red blood cells (RBC) to lipid peroxidation from patients on continuous ambulatory peritoneal dialysis (CAPD).
Methods
The following parameters were measured: RBC malondialdehyde (MDA) production after oxidative stress with H2O2, RBC antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD), and RBC membrane lipid composition. The levels of plasma vitamin E and serum selenium were also as sayed.
Patients
Eleven patients on continuous ambulatory peritoneal dialysis. Twenty-one healthy blood donors of similar age were used as normal controls.
Results
The MDA formation after H2O2 stimulation was normal in CAPD patients (0.79±0.1 μmol/gHb versus 0.78±0.1 in the control group). RBC from CAPD patients also showed a normal SOD activity, a more than adequate vitamin E status, and a peculiar pattern of membrane lipids, with reduced polyunsaturated fatty acids (p<0.001) and increased monounsaturated fatty acids (p<0.001). Both RBC GSH-Px activity, a selenium-dependent enzyme, and serum selenium levels were significantly lower in CAPD patients, and a significant positive correlation (r=0.68; p<0.02) between the two parameters was found.
Conclusions
This study found a normal sensitivity to oxidant stress in RBC from a group of CAPD patients, despite an impaired GSH-Px activity. The peculiar lipid pattern of RBC membrane, characterized by reduced PUFA and increased MUFA content, may contribute, in addition to adequate SOD activity and vitamin E status, to normal RBC lipid peroxidation.
Keywords
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